MR angiography of peripheral, carotid, and coronary arteries

Alfidi, Ralph J.; Masaryk, Thomas J.; Haacke, E. Mark; Lenz, G.; Ross, J. S.; Modic, Michael T.; Nelson, A.D.; LiPuma, J. P.; Cohen, Alan M.

doi:10.2214/ajr.149.6.1097

Cited by 86 publications

(14 citation statements)

References 44 publications

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“…The maximum signal value is normalized to 1 .O for blood assuming the same TE in each experimcnt. As an example, for N = 0, the entry I .0/90 implies that the peak signal occurs at 90" and is 1 .0 unit. The N = ;x) results are the same as those for stationary blood.…”

Section: Theory (I) Signal Enhancementmentioning

confidence: 99%

“…The development of angiographic imaging (1)(2)(3)(4)(5)(6) has progressed from projective/ subtraction angiography using gradient velocity-compensated/ uncompensated sequences to single acquisition thin slice, high contrast, 3D images of the carotid, intracranial, and peripheral vessels (2)(3)(4)(5). The possibility of acquiring magnetic resonance angiograms quickly and easily has been demonstrated using three-dimensional, short repeat time, gradient echo images (2).…”

Section: Introductionmentioning

confidence: 99%

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Optimizing blood vessel contrast in fast three‐dimensional MRI

Haacke

Masaryk

Wielopolski

et al. 1990

Magnetic Resonance in Med

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Magnetic resonance angiography has matured to the point where clinically useful images can be acquired in half an hour or less. In this paper, the role of 3D imaging techniques is primarily considered. Specifically, the optimal imaging parameters, sequences, and reconstruction techniques are evaluated for moving spins. A variant of FISP known as ROAST with low flip angles, short repeat times, and a thick slab has been found to yield the best 3D survey scan of the cranial vessels with roughly 1 X 1 X 1-mm3 resolution in each of the processed images (slices). For the faster flowing carotids, a sagittal scout with as short a TE as possible is required to avoid spin dephasing. Localization is accomplished in both cases by acquiring thin slab 3D, thin partition, larger flip angle, longer repeat time FLASH sequences. Different choices of dephase/rephase sequences and directions are also reviewed. These choices are discussed from a practical and theoretical perspective. In particular, improvements in contrast and resolution are evaluated using half-Fourier, 512 acquisition, small fields of view and constrained reconstruction for both rephased gradient echo sequences and dephased thin slice long TR spin-echo sequences. A resolution of 0.5-0.75 mm is recommended to obtain sufficient image quality for consistent clinical interpretation of stenoses and vessel abnormalities.

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Section: Theory (I) Signal Enhancementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimizing blood vessel contrast in fast three‐dimensional MRI

Haacke

Masaryk

Wielopolski

et al. 1990

Magnetic Resonance in Med

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show abstract

“…However, in the present study, the faster fluid velocity, the lower fluids signal intensity. Choi et al [25] reported it should be considered as phase effect in addition to the TOF effect., The phase change of spin by motion is represented by φ in the gradient echo technique, so the speed increases in proportion to velocity if the other variables are constant [25,26]. In this study, the flow rate was increased, a laminar flow was formed and the speed difference between the center and periphery in the laminar flow led to an increase in the phase differences because we used saline with a lower viscosity than blood.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Images According to the Fluid Velocity in Time-of-Flight Magnetic Resonance Angiography, and Contrast Enhancement Angiography

Kim¹,

Heo²,

Cho³

et al. 2014

Journal of Magnetics

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In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrastto-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was 2.51 ± 0.12 mm with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

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“…This technique has been firmly established for the imaging of carotid vessels and peripheral arteries [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Resonance Angiography as a Technique for the Visualization of Hemodialysis Shunts

1996

Nephron

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In order to test the suitability of magnetic resonance angiography for the visualization of Brescia-Cimino hemodialysis shunts, 20 patients (8 women, 12 men, aged 24-69 years) were examined with this technique. The shunt arm was placed in an extremity coil. The time-of-flight method was applied. Examination time was less than 15 min. Arterial digital subtraction angiography (DSA) of the shunt arm was carried out additionally in 8 patients in whom pathological results had been obtained. Surgery was performed on 2 patients. In all cases, the feeding artery, anastomosis, and shunt were clearly visible. The results corresponded exactly to those of DSA and, in the patients who had undergone surgery, also to the situs. The patients stated that the examination technique was not very disturbing. Magnetic resonance angiography in the time-of-flight technique seems to be recommendable for the examination of Brescia-Cimino dialysis shunts. Compared to DSA, it has major advantages: it is noninvasive, and no ionizing radiation or contrast medium are associated with the procedure.

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MR angiography of peripheral, carotid, and coronary arteries

Cited by 86 publications

References 44 publications

Optimizing blood vessel contrast in fast three‐dimensional MRI

Optimizing blood vessel contrast in fast three‐dimensional MRI

Analysis of Images According to the Fluid Velocity in Time-of-Flight Magnetic Resonance Angiography, and Contrast Enhancement Angiography

Magnetic Resonance Angiography as a Technique for the Visualization of Hemodialysis Shunts

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