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3036:) can be used to provide the static magnetic field. A permanent magnet that is powerful enough to be used in an MRI will be extremely large and bulky; they can weigh over 100 tonnes. Permanent magnet MRIs are very inexpensive to maintain; this cannot be said of the other types of MRI magnets, but there are significant drawbacks to using permanent magnets. They are only capable of achieving weak field strengths compared to other MRI magnets (usually less than 0.4 T) and they are of limited precision and stability. Permanent magnets also present special safety issues; since their magnetic fields cannot be "turned off," ferromagnetic objects are virtually impossible to remove from them once they come into direct contact. Permanent magnets also require special care when they are being brought to their site of installation.
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2018:(typically corresponding to a patient's head-to-toe direction and colored blue in diagram). Where negative-going gradient pulses are shown, they represent reversal of the gradient direction, i.e., right-to-left, back-to-front or toe-to-head. For human scanning, gradient strengths of 1–100 mT/m are employed: Higher gradient strengths permit better resolution and faster imaging. The pulse sequence shown here would produce a transverse (axial) image.
2444:
1917:
3097:, permitting higher resolution or faster scanning. However, higher field strengths require more costly magnets with higher maintenance costs, and have increased safety concerns. A field strength of 1.0–1.5 T is a good compromise between cost and performance for general medical use. However, for certain specialist uses (e.g., brain imaging) higher field strengths are desirable, with some hospitals now using 3.0 T scanners.
3331:
some of the spatial coding originating from the magnetic gradients with the spatial sensitivity of the different coil elements. However, the increased acceleration also reduces the signal-to-noise ratio and can create residual artifacts in the image reconstruction. Two frequently used parallel acquisition and reconstruction schemes are known as SENSE and GRAPPA. A detailed review of parallel imaging techniques can be found here:
2257:
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33:
3082:, also known as a coldhead, is used to recondense some helium vapor back into the liquid helium bath. Several manufacturers now offer 'cryogenless' scanners, where instead of being immersed in liquid helium the magnet wire is cooled directly by a cryocooler. Alternatively, the magnet may be cooled by carefully placing liquid helium in strategic spots, dramatically reducing the amount of liquid helium used, or,
3066:, losing resistance to flow of electric current. An electromagnet constructed with superconductors can have extremely high field strengths, with very high stability. The construction of such magnets is extremely costly, and the cryogenic helium is expensive and difficult to handle. However, despite their cost, helium cooled superconducting magnets are the most common type found in MRI scanners today.
1989:, the horizontal axis represents time. The vertical axis represents: (top row) amplitude of radio frequency pulses; (middle rows) amplitudes of the three orthogonal magnetic field gradient pulses; and (bottom row) receiver analog-to-digital converter (ADC). Radio frequencies are transmitted at the Larmor frequency of the nuclide to be imaged. For example, for H in a magnetic field of 1
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ramped on or off. Typical higher performance gradients have a slew rate of up to 100–200 T·m·s. The slew rate depends both on the gradient coil (it takes more time to ramp up or down a large coil than a small coil) and on the performance of the gradient amplifier (it takes a lot of voltage to overcome the inductance of the coil) and has significant influence on image quality.
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1194:
850:-weighted images. This provides high sensitivity for detection of vascular tissues (e.g., tumors) and permits assessment of brain perfusion (e.g., in stroke). There have been concerns raised recently regarding the toxicity of gadolinium-based contrast agents and their impact on persons with impaired kidney function. (See
1584:
3212:
Some important characteristics of gradient amplifiers and gradient coils are slew rate and gradient strength. As mentioned earlier, a gradient coil will create an additional, linearly varying magnetic field that adds or subtracts from the main magnetic field. This additional magnetic field will have
736:. Contrast in most MR images is actually a mixture of all these effects, but careful design of the imaging pulse sequence allows one contrast mechanism to be emphasized while the others are minimized. The ability to choose different contrast mechanisms gives MRI tremendous flexibility. In the brain,
178:
resonates depends on the strength of the local magnetic field around the proton or group of protons, a stronger field corresponds to a larger energy difference and higher frequency photons. By applying additional magnetic fields (gradients) that vary linearly over space, specific slices to be imaged
3326:
While it is possible to scan using the integrated coil for RF transmission and MR signal reception, if a small region is being imaged, then better image quality (i.e., higher signal-to-noise ratio) is obtained by using a close-fitting smaller coil. A variety of coils are available which fit closely
3023:
Just as important as the strength of the main magnet is its precision. The straightness of the magnetic lines within the center (or, as it is technically known, the iso-center) of the magnet needs to be near-perfect. This is known as homogeneity. Fluctuations (inhomogeneities in the field strength)
2949:
are: the main magnet, which polarizes the sample, the shim coils for correcting inhomogeneities in the main magnetic field, the gradient system which is used to localize the MR signal and the RF system, which excites the sample and detects the resulting NMR signal. The whole system is controlled by
4885:
This unrealistically assumes that the gradient is linear out to the end of the magnet bore. While this assumption is fine for pedagogical purposes, in most commercial MRI systems the gradient droops significantly after a much smaller distance; indeed, the decrease in the gradient field is the main
3330:
A recent development in MRI technology has been the development of sophisticated multi-element phased array coils which are capable of acquiring multiple channels of data in parallel. This 'parallel imaging' technique uses unique acquisition schemes that allow for accelerated imaging, by replacing
546:
variety of RF and gradient pulse sequences that gives MRI its versatility. Change of field gradient spreads the responding FID signal in the frequency domain, but this can be recovered and measured by a refocusing gradient (to create a so-called "gradient echo"), or by a radio frequency pulse (to
3318:
produced by nuclear relaxation inside the subject is true EM radiation (radio waves), and these leave the subject as RF radiation, but they are of such low power as to also not cause appreciable RF interference that can be picked up by nearby radio tuners (in addition, MRI scanners are generally
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per centimeter or millitesla per meter (mT/m). High performance gradient coils used in MRI are typically capable of producing a gradient magnetic field of approximate 30 mT/m or higher for a 1.5 T MRI. The slew rate of a gradient system is a measure of how quickly the gradients can be
413:
is due to a tiny excess of protons in the lower energy state. This gives a net polarization that is parallel to the external field. Application of an RF pulse can tip this net polarization vector sideways (with, i.e., a so-called 90° pulse), or even reverse it (with a so-called 180° pulse). The
2029:
of longitudinal nuclear magnetization within a slab, or slice, creating transverse magnetization. The second part of the pulse sequence, PE, imparts a phase shift upon the slice-selected nuclear magnetization, varying with its location in the Y direction. The third part of the pulse sequence,
3208:
Scan speed is dependent on performance of the gradient system. Stronger gradients allow for faster imaging, or for higher resolution; similarly, gradient systems capable of faster switching can also permit faster scanning. However, gradient performance is limited by safety concerns over nerve
541:
coil to vary across the scanned region, so that different spatial locations become associated with different precession frequencies. Only those regions where the field is such that the precession frequencies match the RF frequency will experience excitation. Usually, these field gradients are
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oxygen in air) making, for example, the frontal lobes of the brain difficult to image. To restore field homogeneity a set of shim coils is included in the scanner. These are resistive coils, usually at room temperature, capable of producing field corrections distributed as several orders of
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wound from copper wire is an alternative to a permanent magnet. An advantage is low initial cost, but field strength and stability are limited. The electromagnet requires considerable electrical energy during operation which can make it expensive to operate. This design is essentially
3205:-axis gradient is applied, the field strength may be 1.45 T at one end of a 1 m long bore and 1.55 T at the other). It is the magnetic gradients that determine the plane of imaging—because the orthogonal gradients can be combined freely, any plane can be selected for imaging.
3020:. Clinical magnets generally have a field strength in the range 0.1–3.0 T, with research systems available up to 9.4 T for human use and 21 T for animal systems. In the United States, field strengths up to 7 T have been approved by the FDA for clinical use.
989:
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of the protons align to be either parallel or anti-parallel to the direction of the field. While each individual proton can only have one of two alignments, the collection of protons appear to behave as though they can have any alignment. Most protons align parallel to
2286:
Low signal for fat − Note that this only applies to standard Spin Echo (SE) sequences and not the more modern Fast Spin Echo (FSE) sequence (also referred to as Turbo Spin Echo, TSE), which is the most commonly used technique today. In FSE/TSE, fat will have a high
161:
pulse is then applied, which can excite protons from parallel to anti-parallel alignment, only the latter are relevant to the rest of the discussion. In response to the force bringing them back to their equilibrium orientation, the protons undergo a rotating motion
3121:
When the MR scanner is placed in the hospital or clinic, its main magnetic field is far from being homogeneous enough to be used for scanning. That is why before doing fine tuning of the field using a sample, the magnetic field of the magnet must be measured and
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decay, dephasing due to field inhomogeneity, flow, diffusion, etc. and any other phenomena that affect that amount of transverse magnetization available to induce signal in the RF probe or its phase with respect to the receiving coil' s electromagnetic field.
3267:. That coil is usually built into the body of the scanner. The power of the transmitter is variable, but high-end whole-body scanners may have a peak output power of up to 35 kW, and be capable of sustaining average power of 1 kW. Although these
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signal in the absence of field gradients. The FID from a poorly shimmed sample will show a complex decay envelope, often with many humps. Shim currents are then adjusted to produce a large amplitude exponentially decaying FID, indicating a homogeneous
1898:
677:
scanning or where images are needed very rapidly, is called echo-planar imaging (EPI): In this case, each RF excitation is followed by a train of gradient echoes with different spatial encoding. Multiplexed-EPI is even faster, e.g., for whole brain
3089:
Magnets are available in a variety of shapes. However, permanent magnets are most frequently C-shaped, and superconducting magnets most frequently cylindrical. C-shaped superconducting magnets and box-shaped permanent magnets have also been used.
1413:
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are most often used to generate a detectable radio-frequency signal that is received by antennas close to the anatomy being examined. Hydrogen atoms are naturally abundant in people and other biological organisms, particularly in
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are a few tens of milliseconds. However, these values can vary widely between different tissues, as well as between different external magnetic fields. This behavior is one factor giving MRI its tremendous soft tissue contrast.
95:, and cardiac pacemakers nowadays may also have an MRI in spite of effects of the strong magnetic fields. This does not apply on older devices, and details for medical professionals are provided by the device's manufacturer.
3133:
boundaries within that sample, causing signal dropout (regions showing no signal) and spatial distortions in acquired images. For humans or animals the effect is particularly pronounced at air-tissue boundaries such as the
3238:) is useful for imaging. Along any given axis, the gradient will add to the magnetic field on one side of the zero position and subtract from it on the other side. Since the additional field is a gradient, it has units of
2030:
another slice selection (of the same slice) uses another shaped pulse to cause a 180° rotation of transverse nuclear magnetization within the slice. This transverse magnetisation refocuses to form a spin echo at a time
662:(2DFT) technique with slice selection, or by the three-dimensional Fourier transform (3DFT) technique. Another name for 2DFT is spin-warp. What follows here is a description of the 2DFT technique with slice selection.
3200:
which permit rapid and precise adjustments to their field strength and direction. Typical gradient systems are capable of producing gradients from 20 to 100 mT/m (i.e., in a 1.5 T magnet, when a maximal
2123:-space data, a two-dimensional inverse Fourier transform is performed to provide the familiar MR image. Either the magnitude or phase of the Fourier transform can be taken, the former being far more common.
2037:. During the spin echo, a frequency-encoding (FE) or readout gradient is applied, making the resonant frequency of the nuclear magnetization vary with its location in the X direction. The signal is sampled
3180:
Gradient coils are used to spatially encode the positions of protons by varying the magnetic field linearly across the imaging volume. The Larmor frequency will then vary as a function of position in the
1189:{\displaystyle S(t)={\tilde {\rho }}_{\mathrm {eff} }\left({\vec {k}}(t)\right)\equiv \int _{-\infty }^{\infty }\mathrm {d} {\vec {x}}\ \rho ({\vec {x}})\cdot e^{2\pi i\ {\vec {k}}(t)\cdot {\vec {x}}}}
3631:
Weissleder R, Elizondo G, Wittenberg J, Rabito CA, Bengele HH, Josephson L (May 1990). "Ultrasmall superparamagnetic iron oxide: characterization of a new class of contrast agents for MR imaging".
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1597:, in particular) to understand the role of phase encoding (the so-called spin-warp method). In a standard spin echo or gradient echo scan, where the readout (or view) gradient is constant (e.g.,
474:
When the radio frequency pulse is turned off, the transverse vector component produces an oscillating magnetic field which induces a small current in the receiver coil. This signal is called the
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is created by differences in the strength of the NMR signal recovered from different locations within the sample. This depends upon the relative density of excited nuclei (usually
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Imaging
Systems for Medical Diagnostics: Fundamentals, Technical Solutions and Applications for Systems Applying Ionizing Radiation, Nuclear Magnetic Resonance and Ultrasound
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component (such as all conventional radio wave transmissions have). Thus, the high-powered electromagnetic field produced in the MRI transmitter coil does not produce much
1401:
2912:
1777:
1748:
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Griswold MA, Jakob PM, Heidemann RM, Nittka M, Jellus V, Wang J, Kiefer B, Haase A (June 2002). "Generalized autocalibrating partially parallel acquisitions (GRAPPA)".
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The magnet is the largest and most expensive component of the scanner, and the remainder of the scanner is built around it. The strength of the magnet is measured in
1579:{\displaystyle I\left({\vec {x}}\right)=\int _{-\infty }^{\infty }\mathrm {d} {\vec {k}}\ S\left({\vec {k}}(t)\right)\cdot e^{-2\pi i\ {\vec {k}}(t)\cdot {\vec {x}}}}
1642:-space are scanned in opposite directions, this must be taken into account in the reconstruction. Multi-shot EPI and fast spin echo techniques acquire only part of
1787:-space determines the field of view of the image (maximum frequency that is correctly sampled) and the maximum value of k sampled determines the resolution; i.e.,
370:
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201:
on the current flowing in the gradient coils, the gradient coils will try to move producing loud knocking sounds, for which patients require hearing protection.
3440:
Poustchi-Amin M, Mirowitz SA, Brown JJ, McKinstry RC, Li T (2000). "Principles and applications of echo-planar imaging: a review for the general radiologist".
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axis. When a non-zero phase-encoding pulse is added in between the RF excitation and the commencement of the readout gradient, this line moves up or down in
1205:
658:
Although each of these schemes is occasionally used in specialist applications, the majority of MR Images today are created either by the two-dimensional
4760:
4735:
Obasih KM, Mruzek (1996). "Thermal design and analysis of a cryogenless superconducting magnet for interventional MRI therapy". In
Timmerhaus KD (ed.).
4633:
3823:
3287:, there is very little RF interference produced by the MRI machine. The reason for this, is that the MRI is not a radio transmitter. The RF frequency
2749:
Magnetic labeling of arterial blood below the imaging slab, which subsequently enters the region of interest. It does not need gadolinium contrast.
2119:
After the two-dimensional matrix (typical dimension between 128 × 128 and 512 × 512) has been acquired, producing the so-called
91:
and is, therefore, a safe procedure suitable for diagnosis in children and repeated runs. Patients with specific non-ferromagnetic metal implants,
4331:
Chua TC, Wen W, Slavin MJ, Sachdev PS (February 2008). "Diffusion tensor imaging in mild cognitive impairment and
Alzheimer's disease: a review".
4253:"Signal evolution and infarction risk for apparent diffusion coefficient lesions in acute ischemic stroke are both time- and perfusion-dependent"
5133:
2819:
Localizing brain activity from performing an assigned task (e.g. talking, moving fingers) before surgery, also used in research of cognition.
3303:
at its RF frequency, and the power is confined to the coil space and not radiated as "radio waves." Thus, the transmitting coil is a good EM
929:-space formalism, a technique that proved invaluable in unifying different MR imaging techniques. They showed that the demodulated MR signal
4713:
3701:
Twieg DB (1983). "The k-trajectory formulation of the NMR imaging process with applications in analysis and synthesis of imaging methods".
778:
imaging, whereas proton-density-weighted imaging provides little contrast in healthy subjects. Additionally, functional parameters such as
937:) generated by the interaction between an ensemble of freely precessing nuclear spins in the presence of a linear magnetic field gradient
888:
tissue retains the agent, but abnormal areas (e.g., scars, tumors) do not. They can also be taken orally, to improve visualization of the
3078:, ambient heat causes the helium to slowly boil off. Such magnets, therefore, require regular topping-up with liquid helium. Generally a
665:
The 3DFT technique is rather similar except that there is no slice selection and phase-encoding is performed in two separate directions.
3534:
Weinmann HJ, Brasch RC, Press WR, Wesbey GE (March 1984). "Characteristics of gadolinium-DTPA complex: a potential NMR contrast agent".
733:
4776:"Japan makes progress toward realization of MRI magnets using high temperature superconducting wire materials | NextBigFuture.com"
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Two gradients with equal magnitude, but opposite direction, are used to encode a phase shift, which is proportional to the velocity of
2620:
Reduced T2 weighting by taking multiple conventional DWI images with different DWI weighting, and the change corresponds to diffusion.
4994:
2068:
times, but with the phase-encoding gradient incremented (indicated by the horizontal hatching in the green gradient block). Typically
1683:-space in determining image contrast can be exploited in more advanced imaging techniques. One such technique is spiral acquisition—a
4696:
2879:
3596:
Widder DJ, Greif WL, Widder KJ, Edelman RR, Brady TJ (February 1987). "Magnetite albumin microspheres: a new MR contrast material".
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174:, which yields a changing voltage in the receiver coils to give a signal. The frequency at which a proton or group of protons in a
2414:
3475:
Feinberg DA, Moeller S, Smith SM, Auerbach E, Ramanna S, Gunther M, Glasser MF, Miller KL, Ugurbil K, Yacoub E (December 2010).
123:. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the
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Most superconducting magnets have their coils of superconductive wire immersed in liquid helium, inside a vessel called a
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166:), much like a spun wheel under the effect of gravity. The protons will return to the low energy state by the process of
2432:
Spoiled gradient recalled echo (GRE), fully flow compensated, long echo time, combines phase image with magnitude image
2376:
855:
629:
A number of schemes have been devised for combining field gradients and radio frequency excitation to create an image:
4775:
1964:
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1946:
1638:-space is scanned in a single shot, following either a sinusoidal or zig-zag trajectory. Since alternating lines of
3024:
within the scan region should be less than three parts per million (3 ppm). Three types of magnets have been used:
1646:-space per excitation. In each shot, a different interleaved segment is acquired, and the shots are repeated until
5284:
Spatially
Resolved Magnetic Resonance: Methods, Materials, Medicine, Biology, Rheology, Geology, Ecology, Hardware
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Pruessmann KP, Weiger M, Scheidegger MB, Boesiger P (November 1999). "SENSE: sensitivity encoding for fast MRI".
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particles, whenever the spin of a single proton is measured it can only have one of two results commonly called
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1942:
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energy transition, and magnetic field gradients localize the signal in space. By varying the parameters of the
4536:
Turnbull LW (January 2009). "Dynamic contrast-enhanced MRI in the diagnosis and management of breast cancer".
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Magnetic field strength is an important factor in determining image quality. Higher magnetic fields increase
2958:
980:
1593:-space formalism, a number of seemingly complex ideas became simple. For example, it becomes very easy (for
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2809:
2797:
2561:
2677:
1893:{\displaystyle {\rm {FOV}}\propto {\frac {1}{\Delta k}}\qquad \mathrm {Resolution} \propto |k_{\max }|\ .}
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Magnetic
Resonance Microscopy: Methods and Applications in Materials Science, Agriculture and Biomedicine
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Permanent magnet: Conventional magnets made from ferromagnetic materials (e.g., steel alloys containing
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The first part of the pulse sequence, SS, achieves "slice selection". A shaped pulse (shown here with a
1718:(CNR) when compared to conventional zig-zag acquisitions, especially in the presence of rapid movement.
520:. At the same time, the longitudinal magnetization starts to recover exponentially with a time constant
4113:
3569:
Laniado M, Weinmann HJ, Schörner W, Felix R, Speck U (1984). "First use of GdDTPA/dimeglumine in man".
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1605:-space is scanned per RF excitation. When the phase encoding gradient is zero, the line scanned is the
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3900:"A Current Review of the Meniscus Imaging: Proposition of a Useful Tool for Its Radiologic Analysis"
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is 'shimmed' by adjusting currents in the shim coils. Field homogeneity is measured by examining an
1981:
Simplified timing diagram for two-dimensional-Fourier-transform (2DFT) Spin Echo (SE) pulse sequence
551:"), or in digital post-processing of the spread signal. The whole process can be repeated when some
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in order to investigate the anatomy and physiology of the body, and to detect pathologies including
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2011:(typically corresponding to a patient's front-to-back direction and colored green in diagram), and
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1630:-space formalism also makes it very easy to compare different scanning techniques. In single-shot
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appears dark. The contrast of white matter, gray matter and cerebrospinal fluid is reversed using
71:, disorders of muscles and joints, and abnormalities in the heart and blood vessels among others.
5325:
4761:"Philips Helium-Free MRI System Combines Productivity with High Quality Imaging | Medgadget"
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around parts of the body such as the head, knee, wrist, breast, or internally, e.g., the rectum.
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of the trajectory proportional to the vector of the applied magnetic field gradient. By the term
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3985:"Principles, techniques, and applications of T2*-based MR imaging and its special applications"
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1986:
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In some situations it is not possible to generate enough image contrast to adequately show the
344:
can be used to describe the behaviour of an ensemble of protons adequately. As with other spin
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3417:
How does MRI work?: An
Introduction to the Physics and Function of Magnetic Resonance Imaging
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2004:(typically corresponding to a patient's left-to-right direction and colored red in diagram),
633:
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Quantum mechanics is required to accurately model the behaviour of a single proton. However,
326:): one low-energy and one high-energy, which are separated by a very small splitting energy.
4304:
3477:"Multiplexed echo planar imaging for sub-second whole brain FMRI and fast diffusion imaging"
2775:
Faster Gd contrast uptake along with other features is suggestive of malignancy (pictured).
1710:
decay the signal is greatest at the start of the acquisition, hence acquiring the center of
892:, and to prevent water in the gastrointestinal tract from obscuring other organs (e.g., the
501:, which shortens the FID. The time constant for the observed decay of the FID is called the
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475:
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Ljunggren S (1983). "A simple graphical representation of
Fourier-based imaging methods".
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732:) of those nuclei after the pulse sequence, and often on other parameters discussed under
8:
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4928:, Edelstein WA, Hayes CE, Souza SP, Mueller OM (November 1990). "The NMR phased array".
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of that proton which is a linear combination of the parallel and anti-parallel states.
88:
5162:
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The receiver consists of the coil, pre-amplifier and signal processing system. The RF
843:
compound) is given. Gadolinium-enhanced tissues and fluids appear extremely bright on
398:. The static fields used most commonly in MRI cause precession which corresponds to a
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4404:"Magnetic resonance diffusion-perfusion mismatch in acute ischemic stroke: An update"
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times by the ADC during this period, as represented by the vertical lines. Typically
1283:{\displaystyle {\vec {k}}(t)\equiv \int _{0}^{t}{\vec {G}}(\tau )\ \mathrm {d} \tau }
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of the spin system, or the number of nuclei with parallel versus anti-parallel spin.
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The longitudinal magnetisation is then allowed to recover somewhat and after a time
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4838:"Automatic, localized in vivo adjustment of all first- and second-order shim coils"
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After a sample is placed into the scanner, the main magnetic field is distorted by
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2853:, giving it a much higher signal when using short echo time and flow compensation.
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Maintenance of a steady, residual transverse magnetisation over successive cycles.
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72:
48:
2997:
A short extract of a 20-minute scanning session, recorded outside the above unit
941:
and a receiver-coil equals the
Fourier transform of the effective spin density,
3386:
3296:
3074:. Despite thermal insulation, sometimes including a second cryostat containing
2507:
2463:
2403:
Spoiled gradient recalled echo (GRE) with a long echo time and small flip angle
1779:
are conjugate variables (with respect to the
Fourier transform) we can use the
901:
538:
490:
399:
373:
311:
280:
240:
214:
128:
124:
107:
99:
4794:"High-temperature superconducting coils tested for future NMR magnet - MagLab"
3819:
2311:
442:. The loss of phase coherence in the transverse plane is called transverse or
5406:
3284:
3196:
Gradient coils are usually resistive electromagnets powered by sophisticated
3059:
2685:
2356:
2291:
2241:
1715:
920:
683:
377:
323:
318:
around an axis along the direction of the field. Protons align in two energy
191:
184:
171:
111:
5077:
Blaimer M, Breuer F, Mueller M, Heidemann RM, Griswold MA, Jakob PM (2004).
1977:
482:
experiment, the FID decays approximately exponentially with a time constant
5186:
5105:
5055:
5002:
4941:
4856:
4557:
4439:
4352:
4286:
4018:
3935:
3916:
3520:
3461:
3320:
3239:
3225:; however, only the component along the magnetic field (usually called the
3139:
3017:
2648:
2547:
2478:
2220:
2159:
2132:
1990:
897:
869:
836:
744:
376:. When we discuss the state of a proton or protons we are referring to the
64:
37:
5170:
4949:
4864:
3730:
3652:
3617:
3609:
3582:
3555:
3547:
2526:
609:(III) work by altering (shortening) the relaxation parameters, especially
5305:
Principles of
Magnetic Resonance Imaging: A Signal Processing Perspective
4995:
10.1002/(SICI)1522-2594(199911)42:5<952::AID-MRM16>3.0.CO;2-S
4666:
4608:
4514:
4486:
4420:
4380:
4309:
4203:
4175:
4147:
4063:
4000:
3958:
3876:
3256:
3055:
2407:
2332:
1654:-space represent lower spatial frequencies than the data at the edges of
1293:
In other words, as time progresses the signal traces out a trajectory in
752:
570:
542:
modulated to sweep across the region to be scanned, and it is the almost
4886:
delimiter of the useful field of view of a modern commercial MRI system.
3112:
FID signal from a well shimmed sample, showing a pure exponential decay.
2705:
Measures changes over time in susceptibility-induced signal loss due to
2485:
5227:
NMR Imaging in Biomedicine: Supplement 2 Advances in Magnetic Resonance
3898:
Lefevre N, Naouri JF, Herman S, Gerometta A, Klouche S, Bohu Y (2016).
3197:
3108:
3079:
3006:
2813:
2519:
2228:
2216:
866:
840:
831:, taken orally, for imaging the stomach and small bowel. However, most
823:
of interest by adjusting the imaging parameters alone, in which case a
606:
566:(TR) is the time between two successive excitations of the same slice.
315:
260:
163:
5047:
4226:
3100:
835:
are selected for their specific magnetic properties. Most commonly, a
79:
or into a joint to enhance the image and facilitate diagnosis. Unlike
5282:
Blümer P (1998). Blümler P, Blümich B, Botto RE, Fukushima E (eds.).
4901:
4549:
3722:
3272:
3033:
2941:
Schematic of construction of a cylindrical superconducting MR scanner
2326:
2224:
2199:
2175:
1994:
1650:-space is sufficiently well-covered. Since the data at the center of
1594:
820:
548:
421:
The recovery of longitudinal magnetization is called longitudinal or
52:
1916:
1365:-space formula, it follows immediately that we reconstruct an image
131:, different contrasts may be generated between tissues based on the
5208:
Magnetic resonance imaging: Physical principles and sequence design
4970:
4716:(Press release). U.S. Food and Drug Administration. 12 October 2017
3439:
3071:
3040:
2901:
2897:
2861:
2857:
2668:
2026:
893:
543:
457:
268:
244:
60:
3630:
2256:
493:
at different spatial locations ("inhomogeneities") that cause the
5385:
Electromagnetic Analysis and Design in Magnetic Resonance Imaging
2779:
2725:
have decreased perfusion and delayed contrast arrival (pictured).
816:
468:
304:
300:
248:
80:
5347:
Magnetic Resonance Imaging: Physical Principles and Applications
2503:
Fluid suppression by setting an inversion time that nulls fluids
32:
5188:
Magnetic Resonance Imaging: Principles, Methods, and Techniques
2963:
748:
489:. However, in practical MRI there are small differences in the
403:
296:
256:
252:
68:
5079:"SMASH, SENSE, PILS, GRAPPA: How to Choose the Optimal Method"
3104:
FID signal from a badly shimmed sample has a complex envelope.
884:-weighted images and may be used for liver imaging, as normal
5205:
5076:
3983:
Chavhan GB, Babyn PS, Thomas B, Shroff MM, Haacke EM (2009).
2470:
2212:
2208:
885:
828:
699:
674:
175:
120:
84:
5023:
3897:
3568:
3474:
2823:
2137:
179:
can be selected, and an image is obtained by taking the 2-D
4659:
4111:
2022:
4251:
An H, Ford AL, Vo K, Powers WJ, Lee JM, Lin W (May 2011).
3846:
Principles and Applications of Radiological Physics E-Book
2871:
925:
In 1983, Ljunggren and Twieg independently introduced the
872:, have become available. These agents appear very dark on
689:
4924:
4688:
Schepkin, Victor D.; Grant, Samuel C.; Cross, Timothy A.
3533:
3347:
Independent (newspaper) obituary of R Edward 20 July 2001
3283:) at powers usually exceeding the highest powers used by
2235:
1997:
would be employed. The three field gradients are labeled
1691:-space to spiral out from the center to the edge. Due to
394:
determined by the particle's gyro-magnetic ratio and the
4737:
Proceedings of the 1995 cryogenic engineering conference
3982:
3790:"Basic proton MR imaging. Tissue Signal Characteristics"
3595:
3414:
1903:(These relationships apply to each axis independently.)
4714:"FDA clears first 7T magnetic resonance imaging device"
2298:
Standard foundation and comparison for other sequences
2251:
Standard foundation and comparison for other sequences
654:
Gradients in the RF field rather than the static field.
209:
The MRI scanner was developed from 1975 to 1977 at the
5327:
Echo-Planar Imaging: Theory, Technique and Application
5206:
Haacke EM, Brown RF, Thompson M, Venkatesan R (1999).
4084:
3062:
to 4 K (−269 °C, −452 °F) it becomes a
2962:
A mobile MRI unit visiting Glebefields Health Centre,
2655:
of water molecules in the directions of nerve fibers.
673:
Another scheme which is sometimes used, especially in
5323:
3848:(6 ed.). Elsevier Health Sciences. p. 292.
1796:
1756:
1727:
1416:
1371:
1311:
1208:
992:
947:
812:
and so can be encoded with suitable pulse sequences.
350:
4376:"Dynamic susceptibility contrast (DSC) MR perfusion"
4330:
2764:
Measures changes over time in the shortening of the
537:
In MRI, the static magnetic field is augmented by a
4105:
3978:
3976:
3571:
Physiological Chemistry and Physics and Medical NMR
3359:
Principles of Nuclear Magnetic Resonance Microscopy
5302:
4298:
4296:
3291:produced in the "transmitting coil" is a magnetic
1892:
1771:
1742:
1578:
1395:
1335:
1282:
1188:
971:
651:Building the image point-by-point or line-by-line.
364:
3891:
3843:
562:of the spins has been more or less restored. The
471:of the system, or the number of nuclei in phase.
310:When these spins are placed in a strong external
5404:
4056:
3973:
3746:
3744:
3742:
3740:
3319:situated in metal mesh lined rooms which act as
1874:
904:have also been studied for potential use in the
4293:
4190:
1687:gradient is applied, causing the trajectory in
5300:
4687:
4510:"Dynamic contrast enhanced (DCE) MR perfusion"
4250:
4196:
3307:transmitter at radio frequency, but a poor EM
1906:
827:may be administered. This can be as simple as
4140:
3737:
3150:After placing the sample in the scanner, the
2932:
2660:Evaluating white matter deformation by tumors
2126:
2075:of between 128 and 512 repetitions are made.
703:
221:. The full body scanner was created in 1978.
4739:. New York: Plenum Press. pp. 305–312.
4734:
4529:
4482:"Arterial spin labelling (ASL) MR perfusion"
4034:
3951:
3812:
3415:Weishaupt D, Koechli VD, Marincek B (2013).
2109:is between 5 ms and 100 ms, while
979:. Fundamentally, the signal is derived from
513:relaxation time, and is always shorter than
418:with the RF pulse and therefore each other.
390:, the protons will appear to precess at the
5262:
4324:
3869:
3844:Graham D, Cloke P, Vosper M (31 May 2011).
3468:
2207:Lower signal for more water content, as in
1945:. Unsourced material may be challenged and
743:-weighting causes the nerve connections of
329:
4628:
4626:
4601:
4572:
4244:
4085:Berger F, de Jonge M, Smithuis R, Maas M.
3837:
3783:
3781:
3779:
3777:
2849:Blood entering the imaged area is not yet
2051:of between 128 and 512 samples are taken.
747:to appear white, and the congregations of
303:or protons, and no net spin; however, the
217:FRS FRSE following from his research into
183:of the spatial frequencies of the signal (
135:properties of the hydrogen atoms therein.
5324:Schmitt F, Stehling MK, Turner R (1998).
5248:. Springer Science & Business Media.
5243:
5224:
5037:
4984:
4806:
4429:
4419:
4276:
4227:"MRI Physics: Diffusion-Weighted Imaging"
4008:
3947:
3945:
3925:
3915:
3665:
3510:
3500:
3419:. Springer Science & Business Media.
3356:
3246:
3172:field. The process is usually automated.
2880:Phase-contrast magnetic resonance imaging
2116:is between 100 ms and 2000 ms.
1965:Learn how and when to remove this message
467:on the other hand is associated with the
5344:
4835:
4809:Biomedical Magnetic Resonance Technology
4535:
4395:
4136:
4134:
4050:
3863:
3107:
3099:
2957:
2936:
1976:
31:
5363:
5184:
4623:
4302:
4114:"Fluid attenuation inversion recoveryg"
3774:
2435:Detecting small amounts of hemorrhage (
690:Image contrast and contrast enhancement
383:In the presence of the magnetic field,
263:, have a non–zero spin and therefore a
14:
5405:
5281:
5246:NMR in Biomedicine: The Physical Basis
5131:
4895:
4634:"Magnetic Resonance Angiography (MRA)"
4401:
4218:
4093:. Radiology Society of the Netherlands
4078:
4030:
4028:
3942:
3598:AJR. American Journal of Roentgenology
3536:AJR. American Journal of Roentgenology
3433:
3259:system consists of an RF synthesizer,
668:
497:to vary across the body. This creates
409:The net longitudinal magnetization in
4581:"Milestone 19: (1990) Functional MRI"
4168:
4131:
3700:
3454:10.1148/radiographics.21.3.g01ma23767
3295:with very little associated changing
3213:components in all 3 directions, viz.
5086:Topics in Magnetic Resonance Imaging
4773:
4660:Keshavamurthy J, Ballinger R et al.
4595:
4507:
4479:
4373:
4143:"Double inversion recovery sequence"
4112:Hacking C, Taghi Niknejad M, et al.
2410:deposits (pictured) and hemorrhages.
2283:Higher signal for more water content
2092:are imposed to ensure that, at time
1943:adding citations to reliable sources
1910:
224:
5382:
4690:"In vivo MR Imaging at 21.1 T"
4501:
4473:
4446:
4367:
4162:
4025:
3787:
2714:Provides measurements of blood flow
2494:Fluid-attenuated inversion recovery
2145:uncommon and experimental sequences
157:as this is a lower energy state. A
24:
5124:
5098:10.1097/01.rmr.0000136558.09801.dd
4224:
3954:"Steady-state free precession MRI"
2971:
1857:
1854:
1851:
1848:
1845:
1842:
1839:
1836:
1833:
1830:
1819:
1805:
1802:
1799:
1462:
1456:
1451:
1273:
1088:
1082:
1077:
1029:
1026:
1023:
624:
106:energy when placed in an external
67:, neurological conditions such as
25:
5424:
5210:. New York: J. Wiley & Sons.
5163:10.1038/scientificamerican0582-78
4037:"Susceptibility weighted imaging"
2651:(pictured) by an overall greater
2466:where the signal of fat is zero.
1336:{\displaystyle \rho ({\vec {x}})}
972:{\displaystyle \rho ({\vec {x}})}
782:, cerebral blood volume (CBV) or
558:-relaxation has occurred and the
4578:
3311:transmitter at radio frequency.
3084:high temperature superconductors
3005:Problems playing this file? See
2987:
2911:
2870:
2822:
2778:
2730:
2676:
2630:
2601:
2560:
2525:
2484:
2442:
2413:
2382:
2347:
2302:
2255:
1915:
1679:The importance of the center of
908:, but are less frequently used.
138:When inside the magnetic field (
110:. In clinical and research MRI,
5301:Liang ZP, Lauterbur PC (1999).
5070:
5017:
4964:
4918:
4889:
4879:
4829:
4800:
4786:
4767:
4753:
4728:
4706:
4681:
4653:
3904:Radiology Research and Practice
3820:"MRI Questions, Fast Spin Echo"
3694:
3659:
3645:10.1148/radiology.175.2.2326474
3624:
3271:are in the RF range of tens of
2696:Dynamic susceptibility contrast
2512:multiple sclerosis (MS) plaques
2061:the whole sequence is repeated
1828:
1616:-space, i.e., we scan the line
267:. In the case of the so-called
5330:. Springer Berlin Heidelberg.
5191:. Medical Physics Publishing.
5026:Magnetic Resonance in Medicine
4973:Magnetic Resonance in Medicine
4930:Magnetic Resonance in Medicine
4845:Magnetic Resonance in Medicine
4774:Wang, Brian (8 January 2017).
4059:"Short tau inversion recovery"
3589:
3562:
3527:
3404:
3379:
3350:
3341:
2927:
2832:Magnetic resonance angiography
2611:Apparent diffusion coefficient
2594:High signal within minutes of
2462:Fat suppression by setting an
2278:by using long TR and TE times
1993:, a frequency of 42.5781
1880:
1865:
1763:
1734:
1669:-space determines the image's
1568:
1556:
1550:
1544:
1507:
1501:
1495:
1472:
1430:
1390:
1384:
1375:
1330:
1324:
1315:
1305:we mean the true spin density
1266:
1260:
1254:
1227:
1221:
1215:
1178:
1166:
1160:
1154:
1125:
1119:
1110:
1098:
1058:
1052:
1046:
1015:
1002:
996:
966:
960:
951:
13:
1:
3668:Journal of Magnetic Resonance
3334:
3048:Superconducting electromagnet
2721:, the infarcted core and the
1396:{\displaystyle I({\vec {x}})}
1343:corrected for the effects of
235:Subatomic particles have the
4402:Chen F, Ni YC (March 2012).
4345:10.1097/WCO.0b013e3282f4594b
4333:Current Opinion in Neurology
4269:10.1161/STROKEAHA.110.610501
4171:"Diffusion weighted imaging"
4057:Sharma R, Taghi Niknejad M.
3752:"Magnetic Resonance Imaging"
3688:10.1016/0022-2364(83)90060-4
3502:10.1371/journal.pone.0015710
3391:Questions and Answers in MRI
3175:
2798:Blood-oxygen-level dependent
2542:Simultaneous suppression of
2454:Short tau inversion recovery
2363:Steady-state free precession
2143:This table does not include
2078:The negative-going lobes in
702:protons), on differences in
456:is thus associated with the
102:are able to absorb and emit
7:
3039:Resistive electromagnet: A
2945:The major components of an
1907:Example of a pulse sequence
833:contrast agents used in MRI
605:, such as those containing
579:is around one second while
287:, sometimes referred to as
283:, such as H, there are two
10:
5429:
5413:Magnetic resonance imaging
5263:Blümich B, Kuhn W (1992).
4807:Chen CN, Hoult DH (1989).
4408:World Journal of Radiology
4305:"Diffusion tensor imaging"
4197:Weerakkody Y, Gaillard F.
3872:"MRI sequences (overview)"
2933:Construction and operation
2816:reflects tissue activity.
2167:Main clinical distinctions
2130:
2127:Overview of main sequences
1772:{\displaystyle {\vec {k}}}
1743:{\displaystyle {\vec {x}}}
1407:of the sampled data, viz.
981:Faraday's law of induction
918:
911:
839:contrast agent (usually a
619:
527:which is much larger than
480:nuclear magnetic resonance
374:parallel and anti-parallel
333:
231:Nuclear magnetic resonance
228:
219:nuclear magnetic resonance
204:
45:Magnetic resonance imaging
5134:"NMR Imaging in Medicine"
4141:Di Muzio B, Abd Rabou A.
3316:electromagnetic radiation
3301:electromagnetic radiation
2953:
2830:
2777:
2774:
2755:Dynamic contrast enhanced
2729:
2711:
2684:
2623:Low signal minutes after
2568:
2534:Double inversion recovery
2473:, such as in more severe
2450:
2355:
2325:(to reduce T1) and short
2174:
2025:modulation) causes a 90°
1405:inverse Fourier transform
780:cerebral blood flow (CBF)
757:cerebrospinal fluid (CSF)
411:thermodynamic equilibrium
243:. Certain nuclei such as
51:technique mostly used in
5366:NMR Imaging of Materials
5132:Pykett IL (1 May 1982).
4836:Gruetter R (June 1993).
4662:"Phase contrast imaging"
4454:"Arterial spin labeling"
4035:Di Muzio B, Gaillard F.
3952:Luijkx T, Weerakkody Y.
3281:electromagnetic spectrum
3116:
2812:-dependent magnetism of
2550:by two inversion times.
2516:subarachnoid haemorrhage
2227:, hyperacute or chronic
1665:value for the center of
499:destructive interference
330:Resonance and relaxation
211:University of Nottingham
3870:du Plessis V, Jones J.
3756:University of Wisconsin
3363:Oxford University Press
2950:one or more computers.
2766:spin–lattice relaxation
2740:Arterial spin labelling
2423:Susceptibility-weighted
2312:Proton density weighted
2192:spin–lattice relaxation
1783:to show that a step in
1716:contrast to noise ratio
1685:rotating magnetic field
1623: = constant.
865:contrast agents, e.g.,
478:(FID). In an idealized
414:protons will come into
190:). Due to the magnetic
168:spin-lattice relaxation
4942:10.1002/mrm.1910160203
4857:10.1002/mrm.1910290613
4639:Johns Hopkins Hospital
4602:Luijkx T, Gaillard F.
4459:University of Michigan
3794:Harvard Medical School
3269:electromagnetic fields
3247:Radio frequency system
3113:
3105:
3013:
2976:
2942:
2851:magnetically saturated
2439:pictured) or calcium.
1982:
1894:
1773:
1744:
1714:-space first improves
1580:
1397:
1337:
1303:effective spin density
1284:
1190:
973:
906:gastrointestinal tract
890:gastrointestinal tract
755:to appear gray, while
366:
145:) of the scanner, the
41:
3610:10.2214/ajr.148.2.399
3548:10.2214/ajr.142.3.619
3289:electromagnetic field
3229:-axis, hence denoted
3111:
3103:
3095:signal-to-noise ratio
3086:may be used instead.
2975:
2961:
2940:
2665:fractional anisotropy
2437:diffuse axonal injury
1980:
1895:
1774:
1745:
1581:
1398:
1338:
1285:
1191:
974:
680:functional MRI (fMRI)
491:static magnetic field
435:with a time constant
396:strength of the field
367:
40:clinical MRI scanner.
35:
5244:Fukushima E (1989).
5225:Mansfield P (1982).
4813:Taylor & Francis
4811:. Medical Sciences.
4763:. 12 September 2018.
4421:10.4329/wjr.v4.i3.63
4001:10.1148/rg.295095034
3917:10.1155/2016/8329296
3387:"Quantum philosophy"
3357:Callaghan P (1994).
2591:of water molecules.
2557:plaques (pictured).
2276:spin–spin relaxation
2244:substances, such as
1939:improve this section
1794:
1754:
1725:
1601:), a single line of
1414:
1369:
1309:
1206:
990:
945:
734:specialized MR scans
640:reconstruction from
547:create a so-called "
476:free induction decay
348:
170:. This appears as a
5368:. Clarendon Press.
5345:Kuperman V (2000).
5155:1982SciAm.246e..78P
5142:Scientific American
4303:Smith D, Bashir U.
4091:Radiology Assistant
3715:1983MedPh..10..610T
3680:1983JMagR..54..338L
3493:2010PLoSO...515710F
3145:spherical harmonics
3058:alloy is cooled by
3030:rare-earth elements
2770:gadolinium contrast
2719:cerebral infarction
2707:gadolinium contrast
2625:cerebral infarction
2596:cerebral infarction
2544:cerebrospinal fluid
2451:Inversion recovery
2246:MRI contrast agents
1460:
1247:
1086:
669:Echo-planar imaging
646:computed tomography
603:MRI contrast agents
560:thermal equilibrium
365:{\displaystyle 1/2}
342:classical mechanics
5364:Blümich B (2000).
5349:. Academic Press.
5185:Sprawls P (2000).
4538:NMR in Biomedicine
4199:"Ischaemic stroke"
4087:"Stress fractures"
3114:
3106:
3014:
2977:
2943:
2768:(T1) induced by a
2686:Perfusion weighted
2570:Diffusion weighted
2555:multiple sclerosis
2508:lacunar infarction
2379:videos (pictured).
2329:(to minimize T2).
1983:
1890:
1769:
1740:
1576:
1443:
1393:
1333:
1280:
1233:
1186:
1069:
969:
362:
237:quantum mechanical
89:ionizing radiation
42:
5394:978-0-8493-9693-9
5375:978-0-19-850683-6
5356:978-0-08-053570-8
5337:978-3-540-63194-1
5316:978-0-7803-4723-6
5293:978-3-527-29637-8
5274:978-3-527-28403-0
5255:978-0-88318-609-1
5236:978-0-323-15406-2
5217:978-0-471-35128-3
5198:978-0-944838-97-6
5180:on 10 March 2016.
5048:10.1002/mrm.10171
4911:978-3-89578-226-8
4896:Oppelt A (2006).
4822:978-0-85274-118-4
4746:978-0-306-45300-7
4702:on 24 April 2008.
4169:Lee M, Bashir U.
3855:978-0-7020-4614-8
3426:978-3-662-07805-1
3372:978-0-19-853997-1
3265:transmitting coil
2992:
2925:
2924:
2810:oxygen saturation
2338:High signal from
2194:by using a short
1975:
1974:
1967:
1886:
1826:
1766:
1737:
1571:
1547:
1537:
1498:
1480:
1475:
1433:
1387:
1327:
1271:
1257:
1218:
1181:
1157:
1147:
1122:
1106:
1101:
1049:
1018:
963:
863:superparamagnetic
784:blood oxygenation
660:Fourier transform
299:have no unpaired
295:. Nuclei such as
225:Nuclear magnetism
181:Fourier transform
93:cochlear implants
16:(Redirected from
5420:
5398:
5379:
5360:
5341:
5320:
5308:
5297:
5278:
5259:
5240:
5221:
5202:
5181:
5179:
5173:. Archived from
5138:
5118:
5117:
5083:
5074:
5068:
5067:
5041:
5021:
5015:
5014:
4988:
4968:
4962:
4961:
4922:
4916:
4915:
4893:
4887:
4883:
4877:
4876:
4842:
4833:
4827:
4826:
4804:
4798:
4797:
4790:
4784:
4783:
4771:
4765:
4764:
4757:
4751:
4750:
4732:
4726:
4725:
4723:
4721:
4710:
4704:
4703:
4701:
4695:. Archived from
4694:
4685:
4679:
4678:
4676:
4674:
4657:
4651:
4650:
4648:
4646:
4630:
4621:
4620:
4618:
4616:
4604:"Functional MRI"
4599:
4593:
4592:
4590:
4588:
4576:
4570:
4569:
4550:10.1002/nbm.1273
4533:
4527:
4526:
4524:
4522:
4505:
4499:
4498:
4496:
4494:
4477:
4471:
4470:
4468:
4466:
4450:
4444:
4443:
4433:
4423:
4399:
4393:
4392:
4390:
4388:
4371:
4365:
4364:
4328:
4322:
4321:
4319:
4317:
4300:
4291:
4290:
4280:
4248:
4242:
4241:
4239:
4237:
4222:
4216:
4215:
4213:
4211:
4194:
4188:
4187:
4185:
4183:
4166:
4160:
4159:
4157:
4155:
4138:
4129:
4128:
4126:
4124:
4109:
4103:
4102:
4100:
4098:
4082:
4076:
4075:
4073:
4071:
4054:
4048:
4047:
4045:
4043:
4032:
4023:
4022:
4012:
3980:
3971:
3970:
3968:
3966:
3949:
3940:
3939:
3929:
3919:
3895:
3889:
3888:
3886:
3884:
3867:
3861:
3859:
3841:
3835:
3834:
3832:
3830:
3824:MRIQuestions.com
3816:
3810:
3809:
3807:
3805:
3796:. Archived from
3785:
3772:
3771:
3769:
3767:
3758:. Archived from
3748:
3735:
3734:
3723:10.1118/1.595331
3698:
3692:
3691:
3663:
3657:
3656:
3628:
3622:
3621:
3593:
3587:
3586:
3566:
3560:
3559:
3531:
3525:
3524:
3514:
3504:
3472:
3466:
3465:
3437:
3431:
3430:
3408:
3402:
3401:
3399:
3397:
3383:
3377:
3376:
3354:
3348:
3345:
3052:niobium-titanium
2994:
2993:
2974:
2915:
2874:
2838:) and venography
2826:
2782:
2734:
2680:
2639:Diffusion tensor
2634:
2605:
2564:
2529:
2488:
2446:
2417:
2406:Low signal from
2386:
2351:
2306:
2259:
2240:High signal for
2234:High signal for
2150:
2149:
2141:
1970:
1963:
1959:
1956:
1950:
1919:
1911:
1899:
1897:
1896:
1891:
1884:
1883:
1878:
1877:
1868:
1860:
1827:
1825:
1814:
1809:
1808:
1778:
1776:
1775:
1770:
1768:
1767:
1759:
1749:
1747:
1746:
1741:
1739:
1738:
1730:
1709:
1708:
1585:
1583:
1582:
1577:
1575:
1574:
1573:
1572:
1564:
1549:
1548:
1540:
1535:
1514:
1510:
1500:
1499:
1491:
1478:
1477:
1476:
1468:
1465:
1459:
1454:
1439:
1435:
1434:
1426:
1402:
1400:
1399:
1394:
1389:
1388:
1380:
1342:
1340:
1339:
1334:
1329:
1328:
1320:
1297:-space with the
1289:
1287:
1286:
1281:
1276:
1269:
1259:
1258:
1250:
1246:
1241:
1220:
1219:
1211:
1195:
1193:
1192:
1187:
1185:
1184:
1183:
1182:
1174:
1159:
1158:
1150:
1145:
1124:
1123:
1115:
1104:
1103:
1102:
1094:
1091:
1085:
1080:
1065:
1061:
1051:
1050:
1042:
1034:
1033:
1032:
1020:
1019:
1011:
978:
976:
975:
970:
965:
964:
956:
883:
882:
811:
810:
777:
776:
731:
730:
704:relaxation times
597:
596:
512:
511:
495:Larmor frequency
392:Larmor frequency
371:
369:
368:
363:
358:
336:Relaxation (NMR)
278:
277:
273:
147:magnetic moments
75:may be injected
57:nuclear medicine
27:Overview article
21:
5428:
5427:
5423:
5422:
5421:
5419:
5418:
5417:
5403:
5402:
5401:
5395:
5376:
5357:
5338:
5317:
5294:
5275:
5256:
5237:
5218:
5199:
5177:
5136:
5127:
5125:Further reading
5122:
5121:
5081:
5075:
5071:
5039:10.1.1.462.3159
5022:
5018:
4986:10.1.1.139.3032
4969:
4965:
4923:
4919:
4912:
4904:. p. 566.
4894:
4890:
4884:
4880:
4840:
4834:
4830:
4823:
4805:
4801:
4792:
4791:
4787:
4780:Next Big Future
4772:
4768:
4759:
4758:
4754:
4747:
4733:
4729:
4719:
4717:
4712:
4711:
4707:
4699:
4692:
4686:
4682:
4672:
4670:
4658:
4654:
4644:
4642:
4632:
4631:
4624:
4614:
4612:
4600:
4596:
4586:
4584:
4577:
4573:
4534:
4530:
4520:
4518:
4506:
4502:
4492:
4490:
4478:
4474:
4464:
4462:
4452:
4451:
4447:
4400:
4396:
4386:
4384:
4372:
4368:
4329:
4325:
4315:
4313:
4301:
4294:
4249:
4245:
4235:
4233:
4223:
4219:
4209:
4207:
4195:
4191:
4181:
4179:
4167:
4163:
4153:
4151:
4139:
4132:
4122:
4120:
4118:radiopaedia.org
4110:
4106:
4096:
4094:
4083:
4079:
4069:
4067:
4055:
4051:
4041:
4039:
4033:
4026:
3981:
3974:
3964:
3962:
3950:
3943:
3896:
3892:
3882:
3880:
3868:
3864:
3856:
3842:
3838:
3828:
3826:
3818:
3817:
3813:
3803:
3801:
3800:on 5 March 2016
3786:
3775:
3765:
3763:
3750:
3749:
3738:
3703:Medical Physics
3699:
3695:
3664:
3660:
3629:
3625:
3594:
3590:
3567:
3563:
3532:
3528:
3473:
3469:
3438:
3434:
3427:
3409:
3405:
3395:
3393:
3385:
3384:
3380:
3373:
3355:
3351:
3346:
3342:
3337:
3279:portion of the
3277:shortwave radio
3261:power amplifier
3253:radio frequency
3249:
3237:
3178:
3171:
3157:
3119:
3076:liquid nitrogen
3012:
3011:
3003:
3001:
3000:
2999:
2998:
2995:
2988:
2985:
2983:Audio recording
2978:
2972:
2967:
2956:
2935:
2930:
2916:
2653:Brownian motion
2589:Brownian motion
2553:High signal of
2506:High signal in
2475:stress fracture
2469:High signal in
2393:
2290:Low signal for
2196:repetition time
2142:
2135:
2129:
2115:
2108:
2098:
2091:
2084:
2074:
2067:
2060:
2050:
2043:
2036:
2017:
2010:
2003:
1971:
1960:
1954:
1951:
1936:
1920:
1909:
1879:
1873:
1869:
1864:
1829:
1818:
1813:
1798:
1797:
1795:
1792:
1791:
1781:Nyquist theorem
1758:
1757:
1755:
1752:
1751:
1729:
1728:
1726:
1723:
1722:
1707:
1704:
1703:
1702:
1697:
1675:
1664:
1622:
1611:
1563:
1562:
1539:
1538:
1522:
1518:
1490:
1489:
1488:
1484:
1467:
1466:
1461:
1455:
1447:
1425:
1424:
1420:
1415:
1412:
1411:
1379:
1378:
1370:
1367:
1366:
1361:From the basic
1356:
1349:
1319:
1318:
1310:
1307:
1306:
1299:velocity vector
1272:
1249:
1248:
1242:
1237:
1210:
1209:
1207:
1204:
1203:
1173:
1172:
1149:
1148:
1135:
1131:
1114:
1113:
1093:
1092:
1087:
1081:
1073:
1041:
1040:
1039:
1035:
1022:
1021:
1010:
1009:
1008:
991:
988:
987:
955:
954:
946:
943:
942:
923:
917:
900:agents such as
881:
878:
877:
876:
861:More recently,
856:Contrast agents
849:
809:
806:
805:
804:
799:
792:
775:
772:
771:
770:
765:
742:
729:
726:
725:
724:
719:
712:
692:
671:
627:
625:Imaging schemes
622:
615:
595:
592:
591:
590:
585:
578:
564:repetition time
557:
533:
526:
519:
510:
507:
506:
505:
488:
466:
455:
448:
441:
427:
389:
354:
349:
346:
345:
338:
332:
275:
271:
270:
265:magnetic moment
233:
227:
207:
200:
159:radio frequency
156:
144:
104:radio frequency
73:Contrast agents
49:medical imaging
28:
23:
22:
15:
12:
11:
5:
5426:
5416:
5415:
5400:
5399:
5393:
5383:Jin J (1998).
5380:
5374:
5361:
5355:
5342:
5336:
5321:
5315:
5298:
5292:
5279:
5273:
5260:
5254:
5241:
5235:
5222:
5216:
5203:
5197:
5182:
5128:
5126:
5123:
5120:
5119:
5092:(4): 223–236.
5069:
5032:(6): 1202–10.
5016:
4963:
4936:(2): 192–225.
4917:
4910:
4888:
4878:
4828:
4821:
4799:
4785:
4766:
4752:
4745:
4727:
4705:
4680:
4652:
4622:
4594:
4571:
4528:
4500:
4472:
4445:
4394:
4366:
4323:
4292:
4263:(5): 1276–81.
4243:
4217:
4189:
4161:
4130:
4104:
4077:
4049:
4024:
3995:(5): 1433–49.
3972:
3941:
3890:
3862:
3854:
3836:
3811:
3773:
3762:on 10 May 2017
3736:
3693:
3674:(2): 338–343.
3658:
3623:
3604:(2): 399–404.
3588:
3561:
3526:
3487:(12): e15710.
3467:
3432:
3425:
3403:
3378:
3371:
3349:
3339:
3338:
3336:
3333:
3297:electric field
3275:(often in the
3248:
3245:
3233:
3177:
3174:
3169:
3155:
3131:susceptibility
3118:
3115:
3068:
3067:
3064:superconductor
3045:
3037:
3002:
2996:
2986:
2981:
2980:
2979:
2970:
2969:
2968:
2955:
2952:
2934:
2931:
2929:
2926:
2923:
2922:
2909:
2894:
2887:
2882:
2876:
2875:
2868:
2854:
2847:
2842:
2841:Time-of-flight
2839:
2828:
2827:
2820:
2817:
2806:
2801:
2795:
2788:Functional MRI
2784:
2783:
2776:
2773:
2762:
2757:
2751:
2750:
2747:
2742:
2736:
2735:
2728:
2727:
2726:
2715:
2710:
2703:
2698:
2693:
2682:
2681:
2674:
2673:
2672:
2661:
2656:
2645:
2640:
2636:
2635:
2628:
2621:
2618:
2613:
2607:
2606:
2599:
2592:
2585:
2580:
2577:
2566:
2565:
2558:
2551:
2540:
2535:
2531:
2530:
2523:
2504:
2501:
2496:
2490:
2489:
2482:
2467:
2464:inversion time
2460:
2455:
2452:
2448:
2447:
2440:
2433:
2430:
2425:
2419:
2418:
2411:
2404:
2401:
2396:
2388:
2387:
2380:
2373:
2370:
2365:
2360:
2353:
2352:
2345:
2344:
2343:
2340:meniscus tears
2330:
2319:
2314:
2308:
2307:
2300:
2296:
2295:
2288:
2284:
2279:
2272:
2267:
2261:
2260:
2253:
2249:
2248:
2238:
2232:
2203:
2188:
2183:
2178:
2172:
2171:
2168:
2165:
2162:
2157:
2154:
2131:Main article:
2128:
2125:
2113:
2106:
2096:
2089:
2082:
2072:
2065:
2058:
2048:
2041:
2034:
2015:
2008:
2001:
1987:timing diagram
1973:
1972:
1955:September 2009
1923:
1921:
1914:
1908:
1905:
1901:
1900:
1889:
1882:
1876:
1872:
1867:
1863:
1859:
1856:
1853:
1850:
1847:
1844:
1841:
1838:
1835:
1832:
1824:
1821:
1817:
1812:
1807:
1804:
1801:
1765:
1762:
1736:
1733:
1705:
1695:
1673:
1662:
1620:
1609:
1587:
1586:
1570:
1567:
1561:
1558:
1555:
1552:
1546:
1543:
1534:
1531:
1528:
1525:
1521:
1517:
1513:
1509:
1506:
1503:
1497:
1494:
1487:
1483:
1474:
1471:
1464:
1458:
1453:
1450:
1446:
1442:
1438:
1432:
1429:
1423:
1419:
1403:by taking the
1392:
1386:
1383:
1377:
1374:
1354:
1347:
1332:
1326:
1323:
1317:
1314:
1291:
1290:
1279:
1275:
1268:
1265:
1262:
1256:
1253:
1245:
1240:
1236:
1232:
1229:
1226:
1223:
1217:
1214:
1197:
1196:
1180:
1177:
1171:
1168:
1165:
1162:
1156:
1153:
1144:
1141:
1138:
1134:
1130:
1127:
1121:
1118:
1112:
1109:
1100:
1097:
1090:
1084:
1079:
1076:
1072:
1068:
1064:
1060:
1057:
1054:
1048:
1045:
1038:
1031:
1028:
1025:
1017:
1014:
1007:
1004:
1001:
998:
995:
968:
962:
959:
953:
950:
919:Main article:
916:
910:
902:barium sulfate
879:
847:
825:contrast agent
807:
797:
790:
773:
763:
740:
727:
717:
710:
691:
688:
670:
667:
656:
655:
652:
649:
626:
623:
621:
618:
613:
593:
583:
576:
569:Typically, in
555:
539:field gradient
531:
524:
517:
508:
486:
464:
453:
446:
439:
425:
400:radiofrequency
387:
361:
357:
353:
334:Main article:
331:
328:
312:magnetic field
229:Main article:
226:
223:
215:Raymond Andrew
206:
203:
198:
154:
142:
129:pulse sequence
112:hydrogen atoms
108:magnetic field
87:, MRI uses no
26:
9:
6:
4:
3:
2:
5425:
5414:
5411:
5410:
5408:
5396:
5390:
5387:. CRC Press.
5386:
5381:
5377:
5371:
5367:
5362:
5358:
5352:
5348:
5343:
5339:
5333:
5329:
5328:
5322:
5318:
5312:
5307:
5306:
5299:
5295:
5289:
5286:. Wiley-VCH.
5285:
5280:
5276:
5270:
5266:
5261:
5257:
5251:
5247:
5242:
5238:
5232:
5228:
5223:
5219:
5213:
5209:
5204:
5200:
5194:
5190:
5189:
5183:
5176:
5172:
5168:
5164:
5160:
5156:
5152:
5148:
5144:
5143:
5135:
5130:
5129:
5115:
5111:
5107:
5103:
5099:
5095:
5091:
5087:
5080:
5073:
5065:
5061:
5057:
5053:
5049:
5045:
5040:
5035:
5031:
5027:
5020:
5012:
5008:
5004:
5000:
4996:
4992:
4987:
4982:
4979:(5): 952–62.
4978:
4974:
4967:
4959:
4955:
4951:
4947:
4943:
4939:
4935:
4931:
4927:
4921:
4913:
4907:
4903:
4899:
4892:
4882:
4874:
4870:
4866:
4862:
4858:
4854:
4851:(6): 804–11.
4850:
4846:
4839:
4832:
4824:
4818:
4814:
4810:
4803:
4795:
4789:
4781:
4777:
4770:
4762:
4756:
4748:
4742:
4738:
4731:
4715:
4709:
4698:
4691:
4684:
4669:
4668:
4663:
4656:
4641:
4640:
4635:
4629:
4627:
4611:
4610:
4605:
4598:
4582:
4575:
4567:
4563:
4559:
4555:
4551:
4547:
4543:
4539:
4532:
4517:
4516:
4511:
4504:
4489:
4488:
4483:
4476:
4461:
4460:
4455:
4449:
4441:
4437:
4432:
4427:
4422:
4417:
4413:
4409:
4405:
4398:
4383:
4382:
4377:
4370:
4362:
4358:
4354:
4350:
4346:
4342:
4338:
4334:
4327:
4312:
4311:
4306:
4299:
4297:
4288:
4284:
4279:
4274:
4270:
4266:
4262:
4258:
4254:
4247:
4232:
4228:
4221:
4206:
4205:
4200:
4193:
4178:
4177:
4172:
4165:
4150:
4149:
4144:
4137:
4135:
4119:
4115:
4108:
4092:
4088:
4081:
4066:
4065:
4060:
4053:
4038:
4031:
4029:
4020:
4016:
4011:
4006:
4002:
3998:
3994:
3990:
3989:Radiographics
3986:
3979:
3977:
3961:
3960:
3955:
3948:
3946:
3937:
3933:
3928:
3923:
3918:
3913:
3909:
3905:
3901:
3894:
3879:
3878:
3873:
3866:
3857:
3851:
3847:
3840:
3825:
3821:
3815:
3799:
3795:
3791:
3784:
3782:
3780:
3778:
3761:
3757:
3753:
3747:
3745:
3743:
3741:
3732:
3728:
3724:
3720:
3716:
3712:
3709:(5): 610–21.
3708:
3704:
3697:
3689:
3685:
3681:
3677:
3673:
3669:
3662:
3654:
3650:
3646:
3642:
3639:(2): 489–93.
3638:
3634:
3627:
3619:
3615:
3611:
3607:
3603:
3599:
3592:
3584:
3580:
3577:(2): 157–65.
3576:
3572:
3565:
3557:
3553:
3549:
3545:
3542:(3): 619–24.
3541:
3537:
3530:
3522:
3518:
3513:
3508:
3503:
3498:
3494:
3490:
3486:
3482:
3478:
3471:
3463:
3459:
3455:
3451:
3448:(3): 767–79.
3447:
3443:
3442:Radiographics
3436:
3428:
3422:
3418:
3412:
3407:
3392:
3388:
3382:
3374:
3368:
3364:
3360:
3353:
3344:
3340:
3332:
3328:
3324:
3322:
3321:Faraday cages
3317:
3312:
3310:
3306:
3302:
3298:
3294:
3290:
3286:
3285:amateur radio
3282:
3278:
3274:
3270:
3266:
3262:
3258:
3254:
3244:
3241:
3236:
3232:
3228:
3224:
3220:
3216:
3210:
3209:stimulation.
3206:
3204:
3199:
3194:
3192:
3188:
3184:
3173:
3168:
3163:
3159:
3154:
3148:
3146:
3141:
3137:
3132:
3127:
3125:
3110:
3102:
3098:
3096:
3091:
3087:
3085:
3081:
3077:
3073:
3065:
3061:
3060:liquid helium
3057:
3053:
3049:
3046:
3042:
3038:
3035:
3031:
3027:
3026:
3025:
3021:
3019:
3010:
3008:
2984:
2965:
2960:
2951:
2948:
2939:
2920:
2914:
2910:
2907:
2903:
2899:
2896:Detection of
2895:
2892:
2888:
2886:
2883:
2881:
2878:
2877:
2873:
2869:
2867:
2863:
2859:
2856:Detection of
2855:
2852:
2848:
2846:
2843:
2840:
2837:
2833:
2829:
2825:
2821:
2818:
2815:
2811:
2807:
2805:
2802:
2799:
2796:
2793:
2789:
2786:
2785:
2781:
2771:
2767:
2763:
2761:
2758:
2756:
2753:
2752:
2748:
2746:
2743:
2741:
2738:
2737:
2733:
2724:
2720:
2716:
2713:
2712:
2708:
2704:
2702:
2699:
2697:
2694:
2691:
2687:
2683:
2679:
2675:
2670:
2667:may indicate
2666:
2662:
2659:
2658:
2657:
2654:
2650:
2646:
2644:
2641:
2638:
2637:
2633:
2629:
2626:
2622:
2619:
2617:
2614:
2612:
2609:
2608:
2604:
2600:
2597:
2593:
2590:
2586:
2584:
2581:
2578:
2575:
2571:
2567:
2563:
2559:
2556:
2552:
2549:
2545:
2541:
2539:
2536:
2533:
2532:
2528:
2524:
2521:
2517:
2513:
2509:
2505:
2502:
2500:
2497:
2495:
2492:
2491:
2487:
2483:
2480:
2476:
2472:
2468:
2465:
2461:
2459:
2456:
2453:
2449:
2445:
2441:
2438:
2434:
2431:
2429:
2426:
2424:
2421:
2420:
2416:
2412:
2409:
2405:
2402:
2400:
2397:
2395:
2392:Effective T2
2390:
2389:
2385:
2381:
2378:
2374:
2371:
2369:
2366:
2364:
2361:
2358:
2357:Gradient echo
2354:
2350:
2346:
2341:
2337:
2336:
2334:
2333:Joint disease
2331:
2328:
2324:
2320:
2318:
2315:
2313:
2310:
2309:
2305:
2301:
2299:
2293:
2289:
2285:
2282:
2281:
2280:
2277:
2273:
2271:
2268:
2266:
2263:
2262:
2258:
2254:
2252:
2247:
2243:
2239:
2237:
2233:
2230:
2226:
2222:
2218:
2214:
2210:
2206:
2205:
2204:
2201:
2197:
2193:
2189:
2187:
2184:
2182:
2179:
2177:
2173:
2169:
2166:
2163:
2161:
2158:
2155:
2152:
2151:
2148:
2146:
2140:
2134:
2124:
2122:
2117:
2112:
2105:
2100:
2095:
2088:
2081:
2076:
2071:
2064:
2057:
2052:
2047:
2040:
2033:
2028:
2024:
2019:
2014:
2007:
2000:
1996:
1992:
1988:
1979:
1969:
1966:
1958:
1948:
1944:
1940:
1934:
1933:
1929:
1924:This section
1922:
1918:
1913:
1912:
1904:
1887:
1870:
1861:
1822:
1815:
1810:
1790:
1789:
1788:
1786:
1782:
1760:
1731:
1719:
1717:
1713:
1701:
1694:
1690:
1686:
1682:
1677:
1672:
1668:
1661:
1657:
1653:
1649:
1645:
1641:
1637:
1633:
1629:
1624:
1619:
1615:
1608:
1604:
1600:
1596:
1592:
1565:
1559:
1553:
1541:
1532:
1529:
1526:
1523:
1519:
1515:
1511:
1504:
1492:
1485:
1481:
1469:
1448:
1444:
1440:
1436:
1427:
1421:
1417:
1410:
1409:
1408:
1406:
1381:
1372:
1364:
1359:
1353:
1350:preparation,
1346:
1321:
1312:
1304:
1300:
1296:
1277:
1263:
1251:
1243:
1238:
1234:
1230:
1224:
1212:
1202:
1201:
1200:
1175:
1169:
1163:
1151:
1142:
1139:
1136:
1132:
1128:
1116:
1107:
1095:
1074:
1070:
1066:
1062:
1055:
1043:
1036:
1012:
1005:
999:
993:
986:
985:
984:
982:
957:
948:
940:
936:
932:
928:
922:
921:K-space (MRI)
914:
909:
907:
903:
899:
895:
891:
887:
875:
871:
870:nanoparticles
868:
864:
859:
857:
853:
846:
842:
838:
834:
830:
826:
822:
818:
813:
803:
796:
789:
785:
781:
769:
762:
758:
754:
750:
746:
739:
735:
723:
716:
709:
705:
701:
697:
687:
685:
684:diffusion MRI
681:
676:
666:
663:
661:
653:
650:
647:
644:, such as in
643:
639:
635:
632:
631:
630:
617:
612:
608:
604:
600:
589:
582:
575:
572:
567:
565:
561:
554:
550:
545:
540:
535:
534:(see below).
530:
523:
516:
504:
500:
496:
492:
485:
481:
477:
472:
470:
463:
459:
452:
445:
438:
434:
433:exponentially
430:
424:
419:
417:
412:
407:
405:
401:
397:
393:
386:
381:
379:
378:wave function
375:
359:
355:
351:
343:
337:
327:
325:
324:Zeeman effect
321:
317:
313:
308:
306:
302:
298:
294:
290:
286:
282:
279:
266:
262:
258:
254:
250:
246:
242:
238:
232:
222:
220:
216:
212:
202:
197:
193:
192:Lorentz force
189:
187:
182:
177:
173:
172:magnetic flux
169:
165:
160:
153:
148:
141:
136:
134:
130:
126:
122:
118:
113:
109:
105:
101:
100:atomic nuclei
96:
94:
90:
86:
82:
78:
77:intravenously
74:
70:
66:
62:
58:
54:
50:
46:
39:
34:
30:
19:
5384:
5365:
5346:
5326:
5304:
5283:
5264:
5245:
5229:. Elsevier.
5226:
5207:
5187:
5175:the original
5149:(5): 78–88.
5146:
5140:
5089:
5085:
5072:
5029:
5025:
5019:
4976:
4972:
4966:
4933:
4929:
4920:
4897:
4891:
4881:
4848:
4844:
4831:
4808:
4802:
4788:
4779:
4769:
4755:
4736:
4730:
4718:. Retrieved
4708:
4697:the original
4683:
4671:. Retrieved
4665:
4655:
4643:. Retrieved
4637:
4613:. Retrieved
4607:
4597:
4585:. Retrieved
4574:
4544:(1): 28–39.
4541:
4537:
4531:
4519:. Retrieved
4513:
4508:Gaillard F.
4503:
4491:. Retrieved
4485:
4480:Gaillard F.
4475:
4463:. Retrieved
4457:
4448:
4414:(3): 63–74.
4411:
4407:
4397:
4385:. Retrieved
4379:
4374:Gaillard F.
4369:
4339:(1): 83–92.
4336:
4332:
4326:
4314:. Retrieved
4308:
4260:
4256:
4246:
4234:. Retrieved
4230:
4220:
4208:. Retrieved
4202:
4192:
4180:. Retrieved
4174:
4164:
4152:. Retrieved
4146:
4121:. Retrieved
4117:
4107:
4095:. Retrieved
4090:
4080:
4068:. Retrieved
4062:
4052:
4040:. Retrieved
3992:
3988:
3963:. Retrieved
3957:
3907:
3903:
3893:
3881:. Retrieved
3875:
3865:
3845:
3839:
3827:. Retrieved
3814:
3802:. Retrieved
3798:the original
3788:Johnson KA.
3764:. Retrieved
3760:the original
3706:
3702:
3696:
3671:
3667:
3661:
3636:
3632:
3626:
3601:
3597:
3591:
3574:
3570:
3564:
3539:
3535:
3529:
3484:
3480:
3470:
3445:
3441:
3435:
3416:
3406:
3394:. Retrieved
3390:
3381:
3358:
3352:
3343:
3329:
3325:
3313:
3308:
3304:
3257:transmission
3250:
3234:
3230:
3226:
3222:
3218:
3214:
3211:
3207:
3202:
3195:
3190:
3186:
3182:
3179:
3166:
3152:
3149:
3140:paramagnetic
3128:
3120:
3092:
3088:
3069:
3022:
3015:
3004:
2946:
2944:
2908:(pictured).
2884:
2844:
2835:
2803:
2791:
2759:
2744:
2700:
2689:
2649:tractography
2642:
2627:(pictured).
2615:
2598:(pictured).
2582:
2579:Conventional
2573:
2548:white matter
2537:
2498:
2479:Shin splints
2457:
2427:
2398:
2394:or "T2-star"
2375:Creation of
2367:
2342:. (pictured)
2335:and injury.
2316:
2297:
2292:paramagnetic
2269:
2250:
2242:paramagnetic
2221:inflammation
2185:
2136:
2133:MRI sequence
2120:
2118:
2110:
2103:
2101:
2093:
2086:
2079:
2077:
2069:
2062:
2055:
2053:
2045:
2038:
2031:
2020:
2012:
2005:
1998:
1984:
1961:
1952:
1937:Please help
1925:
1902:
1784:
1720:
1711:
1699:
1692:
1688:
1680:
1678:
1670:
1666:
1659:
1658:-space, the
1655:
1651:
1647:
1643:
1639:
1635:
1627:
1625:
1617:
1613:
1606:
1602:
1598:
1590:
1588:
1362:
1360:
1351:
1344:
1302:
1294:
1292:
1198:
938:
934:
930:
926:
924:
912:
873:
860:
851:
844:
837:paramagnetic
814:
801:
794:
787:
767:
760:
745:white matter
737:
721:
714:
707:
693:
672:
664:
657:
628:
610:
601:
587:
580:
573:
571:soft tissues
568:
563:
552:
536:
528:
521:
514:
502:
483:
473:
461:
450:
449:relaxation.
443:
436:
422:
420:
408:
384:
382:
339:
309:
292:
288:
239:property of
234:
208:
195:
185:
151:
139:
137:
125:nuclear spin
97:
65:inflammation
43:
29:
4667:Radiopaedia
4609:Radiopaedia
4515:Radiopaedia
4487:Radiopaedia
4381:Radiopaedia
4310:Radiopaedia
4231:XRayPhysics
4204:Radiopaedia
4176:Radiopaedia
4148:Radiopaedia
4064:Radiopaedia
3959:Radiopaedia
3910:: 8329296.
3877:Radiopaedia
3056:niobium-tin
2947:MRI scanner
2928:MRI scanner
2808:Changes in
2709:injection.
2587:Measure of
2522:(pictured).
2408:hemosiderin
2377:cardiac MRI
2265:T2 weighted
2181:T1 weighted
898:Diamagnetic
786:can affect
753:gray matter
642:projections
431:and occurs
320:eigenstates
285:spin states
47:(MRI) is a
18:MRI scanner
4720:7 December
4673:15 October
4645:15 October
4615:16 October
4521:15 October
4493:15 October
4465:27 October
4387:14 October
4316:13 October
4236:15 October
4225:Hammer M.
4210:15 October
4182:13 October
4154:13 October
4123:3 December
4097:13 October
4070:13 October
4042:15 October
3965:13 October
3883:13 January
3335:References
3293:near-field
3198:amplifiers
3080:cryocooler
3018:teslas (T)
3007:media help
2906:dissection
2866:dissection
2814:hemoglobin
2520:meningitis
2294:substances
2274:Measuring
2229:hemorrhage
2217:infarction
2190:Measuring
2102:Typically
1676:contrast.
1595:physicists
1589:Using the
867:iron oxide
841:gadolinium
607:Gadolinium
429:relaxation
164:precession
133:relaxation
5309:. Wiley.
5267:. Wiley.
5034:CiteSeerX
4981:CiteSeerX
4926:Roemer PB
4902:Wiley-VCH
4579:Chou Ih.
3633:Radiology
3309:radiation
3273:megahertz
3176:Gradients
3050:: When a
3044:obsolete.
3034:neodymium
2966:, England
2481:pictured:
2225:infection
2200:echo time
2198:(TR) and
2176:Spin echo
1926:does not
1862:∝
1820:Δ
1811:∝
1764:→
1735:→
1634:, all of
1569:→
1560:⋅
1545:→
1530:π
1524:−
1516:⋅
1496:→
1473:→
1457:∞
1452:∞
1449:−
1445:∫
1431:→
1385:→
1325:→
1313:ρ
1278:τ
1264:τ
1255:→
1235:∫
1231:≡
1216:→
1179:→
1170:⋅
1155:→
1140:π
1129:⋅
1120:→
1108:ρ
1099:→
1083:∞
1078:∞
1075:−
1071:∫
1067:≡
1047:→
1016:~
1013:ρ
961:→
949:ρ
821:pathology
549:spin-echo
53:radiology
36:Modern 3
5407:Category
5106:15548953
5064:14724155
5056:12111967
5011:16046989
5003:10542355
4873:41112243
4587:9 August
4583:. Nature
4558:18654999
4440:22468186
4361:24731783
4353:18180656
4287:21454821
4019:19755604
3936:27057352
3804:14 March
3766:14 March
3521:21187930
3481:PLOS ONE
3462:11353123
3138:(due to
3072:cryostat
3041:solenoid
3032:such as
2902:stenosis
2898:aneurysm
2862:stenosis
2858:aneurysm
2723:penumbra
2669:dementia
2663:Reduced
2170:Example
2156:Sequence
2027:nutation
894:pancreas
858:below.)
696:contrast
544:infinite
458:enthalpy
307:C does.
301:neutrons
213:by Prof
98:Certain
5171:7079720
5151:Bibcode
4958:9482029
4950:2266841
4865:8350724
4566:5305422
4431:3314930
4278:3384724
4010:2799958
3927:4766355
3731:6646065
3711:Bibcode
3676:Bibcode
3653:2326474
3618:3492120
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