Magnetization-prepared IDEAL bSSFP: a flow-independent technique for noncontrast-enhanced peripheral angiography

Purpose:

To propose a new noncontrast‐enhanced flow‐independent angiography sequence based on balanced steady‐state free precession (bSSFP) that produces reliable vessel contrast despite the reduced blood flow in the extremities.

Materials and Methods:

The proposed technique addresses a variety of factors that can compromise the exam success including insufficient background suppression, field inhomogeneity, and large volumetric coverage requirements. A bSSFP sequence yields reduced signal from venous blood when long repetition times are used. Complex‐sum bSSFP acquisitions decrease the sensitivity to field inhomogeneity but retain phase information, so that data can be processed with the Iterative Decomposition of Water and Fat with Echo Asymmetry and Least‐Squares Estimation (IDEAL) method for robust fat suppression. Meanwhile, frequent magnetization preparation coupled with parallel imaging reduces the muscle and long‐T₁ fluid signals without compromising scan efficiency.

Results:

In vivo flow‐independent peripheral angiograms with reliable background suppression and high spatial resolution are produced. Comparisons with phase‐sensitive bSSFP angiograms (that yield out‐of‐phase fat and water signals, and exploit this phase difference to suppress fat) demonstrate enhanced vessel depiction with the proposed technique due to reduced partial‐volume effects and improved venous suppression.

Conclusion:

Magnetization‐prepared complex‐sum bSSFP with IDEAL fat/water separation can create reliable flow‐independent angiographic contrast in the lower extremities. J. Magn. Reson. Imaging 2011;33:931–939. © 2011 Wiley‐Liss, Inc.     

Scoutless stepping-table peripheral contrast-enhanced MR angiography

PURPOSE: To evaluate the feasibility of a scoutless method, termed EZ-STEP, for stepping-table peripheral contrast-enhanced magnetic resonance angiography (CE-MRA). MATERIALS AND METHODS: This scoutless method involves the use of a stepping-table, fast 3D MRA acquisition that incorporates spatially nonselective radiofrequency (RF) pulses for excitation to reduce the repetition time (TR). The sequence was tested in a phantom. The EZ-STEP protocol was optimized in four healthy volunteers and used in 15 subjects. The image quality was scored in a blinded fashion and compared with conventional MRA in eight patients. RESULTS: The acquisition speed of the EZ-STEP sequence was approximately 30% faster in the phantom study compared to the conventional MRA sequence. The total examination time for EZ-STEP was 6 minutes, compared to an average of 23 minutes for conventional MRA. The average image quality scores for EZ-STEP and conventional MRA for stations 1-3 were 3.50 vs. 3.06 (P = 0.087), 3.53 vs. 3.00 (P = 0.033), and 2.97 vs. 2.50 (P = 0.090), respectively. CONCLUSION: EZ-STEP is a more efficient method than the conventional approach for stepping-table peripheral CE-MRA, and provides comparable or better image quality. This method shortens the examination time substantially and eliminates the risk of failing to image a vessel because of improper positioning of the scan volume.     

Three-dimensional respiratory-gated coronary MR angiography with reference to X-ray coronary angiography

Purpose: To assess the clinical value of three-dimensional coronary MR angiography (CMRA) in the detection of significant coronary artery stenosis using conventional X-ray angiography as the standard reference.

Material and Methods: Sixty-nine patients underwent X-ray coronary angiography and CMRA because of suspected or previously diagnosed coronary artery disease. MRI was performed with a 1.5-T whole body imaging system using ECG-triggered 3D gradient echo sequence with retrospective navigator echo respiratory gating and fat suppression.

Results: A total of 276 coronary artery segments were analyzed. The X-ray coronary angiography was normal in 22 patients. Significant proximal stenoses (exceeding 50%) or occlusions were present in 102 coronary artery segments. In all, 120 stenoses or occlusions were identified in CMRA. Sixteen percent of the coronary artery segments had to be excluded because of poor image quality. The overall sensitivity and specificity for MRA for identification of significant stenosis were 75% and 62%, respectively. CMRA correctly detected 89% of patients with at least one vessel disease, but 6 patients with coronary artery disease would have been missed.

Conclusions: Because of the high data exclusion and false- negative case rate, CMRA with retrospective navigator echo triggering is at present not suitable as a clinical screening method in coronary artery disease.     

Contrast-enhanced magnetic resonance angiography in peripheral arterial disease: improving image quality by automated image registration

In peripheral arterial disease, contrast-enhanced MR angiography (MRA) is a noninvasive imaging alternative for catheter-based digital subtraction angiography (DSA). In DSA, final images are generated by subtracting a native mask image from subsequent contrast-enhanced images. Image quality is routinely improved by digitally shifting the mask image prior to subtraction if the patient has moved during angiography. This study investigated whether such image registration may also help to improve the image quality of MRA. In all, 545 MRA examinations of pelvic and leg arteries in patients with symptoms of peripheral arterial disease were studied retrospectively. Standard nonregistered MRA was compared to automatically linear, affine, and warp registered MRA by visual analysis and by three image quality parameters, including vessel detection probability (VDP) of angiographic maximum intensity projections. Most MRA of pelvic and upper leg arteries showed good nonregistered image quality. However, the 15% of lower legs with a body shift of 1 mm or more had relatively low nonregistered image quality, which improved significantly with image registration (VDP gain more than 18%, P < 0.05). The visual analysis gave similar results. In conclusion, image registration can improve image quality of MRA in peripheral arterial disease, especially in the lower legs.     

Two-dimensional multishot echo-planar coronary MR angiography

This work presents a two-dimensional (2D) multishot echo-planar imaging (EPI) technique for magnetic resonance angiography (MRA) of individual coronary arteries in a 17-heart-beat breath-hold. Conventional 2D and 3D segmented gradient-echo (GRE) coronary MRA requires repetitive excitation of the same slice or slab within each cardiac cycle, which can result in reduced blood signal and in motion artifacts. Two-dimensional multishot EPI can address these limitations by eliminating multiple excitations per cardiac cycle, using large flip-angle excitations, markedly reducing the data acquisition window, and performing oblique multislice 2D imaging. The goal of this study was to assess the feasibility of breath-hold 20 multishot EPI for multislice coronary MRA and to demonstrate its reliability by consistently acquiring high-quality images of the coronary arteries in a series of 16 volunteers.     

Need for background suppression in contrast-enhanced peripheral magnetic resonance angiography.

To determine if background suppression is beneficial for peripheral magnetic resonance angiography (pMRA), nonsubtracted, subtracted, and fat-saturated contrast-enhanced (CE) pMRA were compared in 10 patients with peripheral arterial disease. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs), as well as venous enhancement and subjective interpretability, were determined in a station-by-station fashion for each technique. In three patients X-ray angiography was available as a standard of reference. SNRs and CNRs were significantly higher for fat-saturated vs. the other two techniques (P = 0.005). Subjective interpretability was best for subtracted data sets in the lower-leg station. In the iliac station, fat-saturated data sets were considered to have significantly lower interpretability than subtracted data sets. Venous enhancement occurred significantly more often in the lower-leg station with the fat-saturated technique. The value of subtraction depends on the hardware one has available and is a useful tool if dedicated surface coils are used. Background suppression by means of magnitude subtraction leads to the best lower-leg image interpretability. Care must be taken to avoid venous enhancement in the lower-leg station when using fat saturation.     

Soft tissue enhancement on time-resolved peripheral magnetic resonance angiography

PURPOSE: To evaluate the incidence and locations of soft tissue enhancement on time-resolved two-dimensional projection magnetic resonance angiography (MRA) of the calf and foot. MATERIALS AND METHODS: Time-resolved two-dimensional projection MRA of the knee, calf, and foot, performed at 1.5 Tesla using the head coil, was retrospectively reviewed in 326 patients. Soft tissue enhancement of the foot was identified and graded by blinded review. Subsequently, patient medical records were reviewed to determine the presence or absence of diabetes, cellulitis, gangrene, and ulceration of the foot and presence of neuropathic joints. RESULTS: Enhancing spots were identified in 228 patients. For those feet without clinical abnormalities, diabetic patients had an average of 1.2 enhancing spots per foot, while nondiabetics had only 0.6 (P < 0.001). Higher-grade lesions were more prevalent in diabetics and in heavier patients. Of 64 patients with follow-up, 8 (13%) developed cellulitis (N = 4) or ulceration (N = 4) at the location of an enhancing spot, including 5 diabetic and 3 nondiabetic patients. CONCLUSION: Pedal soft tissue enhancement frequently occurs on time-resolved gadolinium (Gd):MRA of the feet. The etiology is uncertain, but the high frequency in diabetic patients and observation of progression to cellulitis/ulceration suggest this soft tissue enhancement may identify sites of subclinical pedal soft tissue injury.     

Optimization of spatial resolution for peripheral magnetic resonance angiography

RATIONALE AND OBJECTIVES: To determine optimum spatial resolution when imaging peripheral arteries with magnetic resonance angiography (MRA). MATERIALS AND METHODS: Eight vessel diameters ranging from 1.0 to 8.0 mm were simulated in a vascular phantom. A total of 40 three-dimensional flash MRA sequences were acquired with incremental variations of fields of view, matrix size, and slice thickness. The accurately known eight diameters were combined pairwise to generate 22 "exact" degrees of stenosis ranging from 42% to 87%. Then, the diameters were measured in the MRA images by three independent observers and with quantitative angiography (QA) software and used to compute the degrees of stenosis corresponding to the 22 "exact" ones. The accuracy and reproducibility of vessel diameter measurements and stenosis calculations were assessed for vessel size ranging from 6 to 8 mm (iliac artery), 4 to 5 mm (femoro-popliteal arteries), and 1 to 3 mm (infrapopliteal arteries). Maximum pixel dimension and slice thickness to obtain a mean error in stenosis evaluation of less than 10% were determined by linear regression analysis. RESULTS: Mean errors on stenosis quantification were 8.8% +/- 6.3% for 6- to 8-mm vessels, 15.5% +/- 8.2% for 4- to 5-mm vessels, and 18.9% +/- 7.5% for 1- to 3-mm vessels. Mean errors on stenosis calculation were 12.3% +/- 8.2% for observers and 11.4% +/- 15.1% for QA software (P = .0342). To evaluate stenosis with a mean error of less than 10%, maximum pixel surface, the pixel size in the phase direction, and the slice thickness should be less than 1.56 mm2, 1.34 mm, 1.70 mm, respectively (voxel size 2.65 mm3) for 6- to 8-mm vessels; 1.31 mm2, 1.10 mm, 1.34 mm (voxel size 1.76 mm3), for 4- to 5-mm vessels; and 1.17 mm2, 0.90 mm, 0.9 mm (voxel size 1.05 mm3) for 1- to 3-mm vessels. CONCLUSION: Higher spatial resolution than currently used should be selected for imaging peripheral vessels.     

Three-dimensional MR angiography in imaging platinum alloy stents

PURPOSE: To evaluate visualization inside platinum stents with three-dimensional contrast-enhanced magnetic resonance angiography (CE-MRA). MATERIALS AND METHODS: Breath-hold three-dimensional gadolinium (Gd) MRA was performed on 18 patients with 22 platinum stents in the renal (n = 18), celiac (n = 1), superior mesenteric (n = 1), and iliac (n = 2) arteries. Electronic calibers were used to measure the lumen diameter within the stent and just distal to the stent to calculate percent stenosis. MRA accuracy was determined from the difference between percent stenosis measured on MRA and digital subtracted angiography (DSA). The patients were imaged at flip angles of 45 degrees , 60 degrees , 75 degrees , 90 degrees , and 150 degrees . RESULTS: MRA demonstrated the stent lumen in all of the patients, with a mean difference between MRA and DSA of 21%. For stents oriented parallel to B0 (iliac arteries) the difference was only 10%, as compared to 22% for stents perpendicular to B0. The flip angle with the best agreement between MRA and DSA was 75 degrees (16%). CONCLUSION: The lumen of a platinum stent can be imaged with three-dimensional CE-MRA, although grading of restenosis has limited accuracy. The best results were obtained with a flip angle of 75 degrees and for stents in the iliac arteries parallel to B0.     

Contrast-enhanced peripheral MR angiography using SENSE in multiple stations: feasibility study

PURPOSE: To investigate if the use of parallel imaging is feasible and beneficial for peripheral contrast-enhanced magnetic resonance angiography (CE-MRA). MATERIALS AND METHODS: A total of 19 consecutive patients underwent peripheral CE-MRA using SENSE with two-fold reduction in the upper and lower leg stations. Conventional nonaccelerated imaging using constant level appearance (CLEAR) was used in the aortoiliac station. The findings were compared with those in a similar patient group that underwent peripheral CE-MR angiography using our standard imaging protocol without SENSE. Intraarterial digital subtraction angiography (IA-DSA) was used as the standard of reference. Lower extremity vessels were divided into anatomic segments (aortoiliac, upper legs, lower legs) for review. In each anatomic segment signal- and contrast-to-noise ratios (SNR, CNR), venous contamination, subjective image quality, as well as sensitivity and specificity, were determined for both patient groups. RESULTS: SNR and CNR improved significantly for the aortoiliac and upper leg segments (all P-values < or = 0.001). Small reductions were seen in the frequency of disturbing venous enhancement (P = not significant). There were no significant differences with regards to subjective image quality or diagnostic accuracy (all P > 0.3). Overall sensitivity and specificity in the SENSE group were 81% and 95%, respectively. For the non-SENSE group, these values were 79% and 96%, respectively. CONCLUSION: Preliminary results show that three-station peripheral CE-MRA using a full length peripheral arterial coil in combination with SENSE in the upper and lower leg stations is feasible and useful for further optimization of peripheral MRA. Using SENSE allows for routine, high-quality depiction of the entire peripheral vascular tree including the pedal arch. Higher SENSE factors are needed for further optimization.     

Non‐contrast‐enhanced flow‐independent peripheral MR angiography with balanced SSFP

Flow‐independent angiography is a non‐contrast‐enhanced technique that can generate vessel contrast even with reduced blood flow in the lower extremities. A method is presented for producing these angiograms with magnetization‐prepared balanced steady‐state free precession (bSSFP). Because bSSFP yields bright fat signal, robust fat suppression is essential for detailed depiction of the vasculature. Therefore, several strategies have been investigated to improve the reliability of fat suppression within short scan times. Phase‐sensitive SSFP can efficiently suppress fat; however, partial volume effects due to fat and water occupying the same voxel can lead to the loss of blood signal. In contrast, alternating repetition time (ATR) SSFP minimizes this loss; however, the level of suppression is compromised by field inhomogeneity. Finally, a new double‐acquisition ATR‐SSFP technique reduces this sensitivity to off‐resonance. In vivo results indicate that the two ATR‐based techniques provide more reliable contrast when partial volume effects are significant. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.     

Improved multi-station peripheral MR angiography with a dedicated vascular coil

Delineation of small branch vessels can be crucial for assessing the peripheral arterial system of patients requiring surgical grafting. Thus signal-to-noise needs to be maximized. We evaluated the performance of a dedicated peripheral vascular coil in four subjects by comparing it to the body coil using DSA as the standard of reference. SNR and CNR values of the dedicated peripheral coil exceeded those obtained with the body coil by a mean of 398%, thus permitting improved delineation of the infrapopliteal arterial morphology.     

Utilizing SENSE to achieve lower station sub-millimeter isotropic resolution and minimal venous enhancement in peripheral MR angiography

PURPOSE: To use the parallel imaging technique, sensitivity encoding (SENSE), to increase spatial resolution and decrease venous contamination in peripheral magnetic resonance angiography (MRA). MATERIALS AND METHODS: Moving table, single-bolus peripheral contrast-enhanced (CE) -MRA was performed on nine patients. Manual table movement combined with SENSE in the upper station allowed for more rapid overall scan coverage such that acquisition of the lower station began 34 seconds after aortic contrast arrival. True sub- millimeter isotropic resolution was achieved in the lower station. RESULTS: Diagnostic MR angiograms of all three stations were obtained in all nine patients. Venous enhancement did not confound interpretation in any case. Sub-millimeter lower station resolution provided excellent vascular detail. CONCLUSION: Decreased delay time between upper and lower station acquisition in single bolus peripheral MR angiograms, now possible using parallel imaging techniques, combined with lower station sub-millimeter resolution may decrease venous contamination and increase overall interpretability, thus increasing clinical acceptance of peripheral MRA.     

Comparison of contrast‐enhanced MR angiography to intraarterial digital subtraction angiography for evaluation of peripheral arterial occlusive disease: Results of a phase III multicenter trial

Purpose

To evaluate the efficacy and safety of 0.1 mmol/kg gadodiamide administration for contrast‐enhanced magnetic resonance angiography (CE‐MRA) in detecting hemodynamically relevant main stenosis (ie, ≥50% or occlusion) of aortoiliac arteries.

Materials and Methods

In a multicenter, phase 3, controlled study, patients with suspected or proven peripheral arterial occlusive disease (PAOD) underwent CE‐MRA with administration of gadodiamide. Intraarterial digital subtraction angiography (IA‐DSA) was used as the reference. The study was approved by all Institutional Review Boards or Institutional Ethic Committees prior to commencement of patient recruitment and written informed consent was obtained from all patients.

Results

Independent readers rated 25%–45% of CE‐MRA images as excellent compared with 0.3%–6% of noncontrast MRA images. Mean imaging acquisition time for CE‐MRA was <1 minute (0.7 ± 1.9 minutes) versus 10 minutes (10.8 ± 3.0) for noncontrast MRA. Sensitivity, specificity, and accuracy of CE‐MRA were superior compared with those of noncontrast MRA in detecting significant arterial stenoses. Compared with IA‐DSA, the sensitivity of CE‐MRA ranged from 80%–88% and the specificity from 73% to 92% for the three blinded readers, at the patient level.

Conclusion

Diagnostic results with CE‐MRA were superior and more consistent compared with noncontrast MRA for detecting hemodynamically relevant main stenoses in patients with suspected or proven PAOD and compared favorably with IA‐DSA as a reference standard. J. Magn. Reson. Imaging 2010;31:1402–1410. © 2010 Wiley‐Liss, Inc.     

三维增强MR血管成像对冠状动脉桥血管的评价

目的：探讨三维增强MR血管成像（3D CEMRA）评价冠状动脉搭桥术（CABG）桥血管开通状况的临床价值。方法：20例CABG患者共47支桥血管，用3D CEMRA方法进行了研究。MR检查距手术15d至16年。20例患者中14例CABG术后5个月至16年有胸痛症状再发，2例术后临床疑桥血管急性闭塞。对3D CEMRA资料进行评价，确认桥血管开通状况。对7例15支桥血管同时有3D CEMRA和X线血管造影者进行了双盲分析。结果：47支桥血管，3D CEMRA显示通畅25支，闭塞22支，闭塞率为46.8％。7例同时有3D CEMRA和X线血管造影者共15支桥血管，通畅8支，闭塞7支，二者显示完全一致。结论：3D CEMRA对桥血管的评价是可靠和准确的，可作为CABG术后患者一种无创性影像检查方法。     

三维增强MR血管成像在周围型动脉闭塞症分级中的应用价值

目的探讨三维增强MR血管成像（3DCE-MRA）在周围型动脉闭塞症（PAOD）分级中的应用价值。方法选择25例临床诊断为PAOD的患者进行3D CE-MRA扫描，采用连续动床三段采集法，高压注射36ml钆喷替酸葡甲胺（GD-DTPA），将采集到的图像进行最大信号投影（MIP）、多平面重组（MPR）或者容积重组（VRT）。结果25例患者成功行3DCE-MRA检查，腹主动脉下段至小腿动脉显示对比度均可达到诊断要求，与DSA和（或）手术结果相比较，3DCE-MRA诊断PAOD总符合率达96．95％（509／525），诊断轻度狭窄、中度狭窄、重度狭窄和闭塞的符合率分别为84．62％（44／52）、84．85％（28／33）、95．45％（21／22）、98．67％（74／75），对轻度、中度、重度狭窄的高估率分别为11．54％（6／52）、12．12％（4／33）、4．55％（1／22），对轻度、中度、重度狭窄和闭塞的低估率分别为3．85％（2／52）、3．03％（1／33）、0（0／22）、1．33％（1／75）。结论3DCE-MRA可以对下肢动脉的狭窄和闭塞进行准确定位和分级，在临床应用中具有重要价值。     

1.0-M gadobutrol versus 0.5-M gadoterate for peripheral magnetic resonance angiography: a prospective randomized controlled clinical trial

PURPOSE: To perform a quantitative and qualitative comparison of gadobutrol and gadoterate in three-station contrast enhanced magnetic resonance angiography (CE-MRA) of the lower limbs. MATERIALS AND METHODS: In this prospective randomized controlled trial, 52 patients with leg ischemia were randomly assigned to one of two groups receiving either gadobutrol (1.0 mmol Gd/mL, 15 mL) or gadoterate (0.5 mmol Gd/mL, 30 mL). Three-station 3D CE-MRAs from the pelvis to the ankles were performed with moving-table technique on a 1.5T MR scanner. Injection time was identical in both groups. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated for 816 arteries. Contrast quality in 1196 vessel segments was evaluated separately by two blinded readers on a three-point scale. RESULTS: Mean SNR (61.8 +/- 7.8 for gadobutrol vs. 61.9 +/- 9.1 for gadoterate, P = 0.257), CNR (52.8 +/- 9.1 vs. 52.8 +/- 10.7, P = 0.154), and qualitative ranking (1.41 vs. 1.44, P = 0.21) for all vessels did not differ significantly between the two patient groups. The overall quality was good in 90.4% with gadoterate and 94.2% with gadobutrol (P = 0.462). CONCLUSION: High-concentration gadobutrol allows neither a higher CNR nor any qualitative advantage over the ordinary unspecific Gd agent gadoterate when the same Gd load and injection times are used in multistation CE-MRA of the peripheral arteries.     

High-resolution continuously acquired peripheral MR angiography featuring partial parallel imaging GRAPPA.

Continuously-moving-table MRI, in contrast to traditional multistation techniques, potentially can improve the scan time efficiency of whole-body applications and provide seamless images of an extended field of view (FOV). Contrast-enhanced MR angiography (CE-MRA) in particular requires high spatial resolution and at the same time has rigid scan time constraints due to the limited arterial contrast window. In this study a reconstruction method for continuously acquired 3D data sets during table movement was combined with a self-calibrated partial parallel imaging algorithm (generalized autocalibrating partially parallel acquisitions (GRAPPA)). The method was applied to peripheral CE-MRA and compared with a standard continuously-moving-table MRA protocol. The gain in scan time was used to increase the data acquisition matrix and decrease the slice thickness. The method was evaluated in five healthy volunteers and applied to one patient with peripheral arterial occlusive disease (PAOD). The protocols were intraindividually compared with respect to the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in selected vessel segments, as well as overall vessel depiction. The combination of the continuously-moving-table technique with parallel imaging enabled the acquisition of seamless peripheral 3D MRA with increased resolution and an overall crisper appearance.     

MRI对四肢神经鞘瘤的诊断价值

目的:探讨四肢神经鞘瘤的MRI表现,提高MRI对四肢神经鞘瘤的诊断率.方法:回顾性分析23例经手术病理证实的四肢神经鞘瘤的MRI资料,其中上肢8例,下肢15例.23例均行常规MRI扫描,包括自旋回波(SE)T1WI,快速自旋回波(FSE)T2WI和SE T1WI增强扫描.结果:23例肿瘤有20例呈椭圆形或梭形,边界清楚光滑,14例位于神经血管束走行区,沿神经走行方向生长,并与神经偏心性相连,9例未追踪到起源神经.21例有完整包膜.绝大多数神经鞘瘤T1WI呈中等至低信号,所有肿瘤T2WI呈不均匀高信号或高低混合信号,增强扫描有不均匀强化.其中显示靶征6例,神经出入征14例,脂肪包绕征10例,脂肪尾征12例.结论:MRI有利于明确肿瘤的位置和范围,靶征、神经出入征、脂肪包绕征和脂肪尾征对诊断有重要价值.     

Signal targeting with alternating radiofrequency (STAR) sequences: Application to MR angiography

We describe a time of flight subtraction method for cine MR angiography that provides nearly perfect suppression of background signal intensity with excellent flow contrast. The method consists of a preparation phase, during which the longitudinal magnetization of the target tissue is inverted on alternate acquisitions and the background tissue is presaturated, followed by a readout phase using a cine segmented turboFLASH sequence with a shared echo modification to improve temporal resolution. With appropriate alternation of the phases of the radiofrequency excitation pulses, there is cancellation of the background signal intensity but flow signal is optimized. By using a thick section (up to 25 mm), substantial portions of the vascular territory are encompassed in a single plane. This permits rapid, dynamic assessment of flow patterns in areas such as the circle of Willis, carotid bifurcation, or renal arteries. Applications of the method for bright and dark blood cine MR angiography are demonstrated.