Whole-body MR angiography using a novel 32-receiving-channel MR system with surface coil technology: first clinical experience

PURPOSE: To demonstrate the feasibility of detecting atherosclerotic vascular disease using an innovative magnetic resonance angiography (MRA) protocol in combination with a dedicated whole-body MR scanner with new surface coil technology. MATERIALS AND METHODS: A total of 10 volunteers and eight patients with peripheral arterial occlusive disease (PAOD) were examined at 1.5 T. Conventional digital subtraction angiography (DSA) of the symptomatic region was available as a reference standard in all eight patients. Depending on subjects' size, four to five three-dimensional data sets were acquired using an adapted injection protocol. Images were assessed independently by two readers for vascular pathology. Additionally, signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were measured. RESULTS: Whole-body MRA yielded excellent sensitivity and specificity of more than 95% for both readers with high interobserver agreement (k = 0.93). Surface coil signal reception rendered a high SNR (mean 151.28 +/- 54.04) and CNR (mean 120.75 +/- 46.47). Despite lower SNR and CNR of the cranial and cervical vessels, a two-step injection protocol exhibited less venous superposition and therefore proved to be superior compared to single-bolus injection. CONCLUSION: Our approach provides accurate noninvasive high-resolution imaging of systemic atherosclerotic disease, covering the arterial vasculature from intracranial arteries to distal runoff vessels. The recently introduced MR scanner and coil technology is feasible to significantly increase the performance of whole-body MRA.     

3.0 Tesla magnetic resonance angiography of endovascular aortic stent grafts: phantom measurements in comparison with 1.5 Tesla

RATIONALE AND OBJECTIVES: This study evaluated different stent grafts by 3 T magnetic resonance angiography (MRA) with respect to lumen visibility, susceptibility-induced signal loss, and type of stent artifacts compared with 1.5 T MRA in a phantom model. METHODS: Six different stent-grafts (tube: n = 3, bifurcated: n = 3) were evaluated by 3 T and 1.5 T MRA using a tube phantom. MRA was performed using T1-weighted sequences at both systems with comparable parameters (3T: TR 5.4/TE 2.0/FA 30 degrees, 1.5 T: TR 6.2/TE 2.2/FA 30 degrees). A blind study of the image quality, including artifacts, was performed by 3 radiologists. Furthermore, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values were calculated. Statistical analysis was performed with Student's t test (P < 0.05). RESULTS: One Elgiloy stent graft showed almost a complete intraluminal signal loss at 1.5 and 3 T. All other models could be evaluated by both systems by MRA, resulting in a favorable lumen visibility (score: 1) for prostheses made of nitinol. Scores for overall image quality and artifacts were the same for both MR systems. SNR and CNR values of the stented part of the vessel phantom increased from 320 +/- 33 to 618 +/- 40 and from 306 +/- 34 to 596 +/- 40 at 3 T when compared with 1.5 T, resulting in a significant signal gain of 93% at the higher field strength. CONCLUSIONS: 3 Tesla MRA of aortic stent grafts in a phantom model demonstrates an increase in SNR and CNR when compared with 1.5 T. However, the magnitude of imaging artifacts as well as coherent intraluminal signal loss within the stent does not increase equally in both MR systems.     

Comparison of contrast‐enhanced multi‐station MR angiography and digital subtraction angiography of the lower extremity arterial disease

Purpose:

To compare diagnostic accuracy of multi‐station, high‐spatial resolution contrast‐enhanced MR angiography (CE‐MRA) of the lower extremities with digital subtraction angiography (DSA) as the reference standard in patients with symptomatic peripheral arterial occlusive disease.

Materials and Methods:

Of 485 consecutive patients undergoing a run‐off CE‐MRA, 152 patients (86 male, 66 female; mean age, 71.6 years) with suspected peripheral arterial occlusive disease were included into our Institutional Review Board approved study. All patients underwent MRA and DSA of the lower extremities within 30 days. MRA was performed at 1.5 Tesla with a single bolus of 0.1 mmol/kg body weight of gadobutrol administered at a rate of 2.0 mL/s at three stations. Two readers evaluated the MRA images independently for stenosis grade and image quality. Sensitivity and specificity were derived.

Results:

Sensitivity and specificity ranged from 73% to 93% and 64% to 89% and were highest in the thigh area. Both readers showed comparable results. Evaluation of good and better quality MRAs resulted in a considerable improvement in diagnostic accuracy.

Conclusion:

Contrast‐enhanced MRA demonstrates good sensitivity and specificity in the investigation of the vasculature of the lower extremities. While a minor investigator experience dependence remains, it is standardizable and shows good inter‐observer agreement. Our results confirm that the administration of Gadobutrol at a standard dose of 0.1 mmol/kg for contrast‐enhanced runoff MRA is able to detect hemodynamically relevant stenoses. Use of contrast‐enhanced MRA as an alternative to intra‐arterial DSA in the evaluation and therapeutic planning of patients with suspected peripheral arterial occlusive disease is well justified. J. Magn. Reson. Imaging 2013;37:1427–1435. © 2012 Wiley Periodicals, Inc.     

Noncontrast 3D steady-state free-precession magnetic resonance angiography of the whole chest using nonselective radiofrequency excitation over a large field of view: comparison with single-phase 3D contrast-enhanced magnetic resonance angiography

OBJECTIVES: To evaluate the feasibility of three-dimensional (3D) steady-state free-precession (SSFP) magnetic resonance angiography (MRA) using nonselective radiofrequency excitation in the assessment of cardiac morphology, thoracic aorta, main pulmonary, and proximal coronary arteries. MATERIAL AND METHODS: Thirty consecutive patients (19 males; 11 females; age range, 20-74) with various cardiac and thoracic vascular diseases underwent free-breathing respiratory navigator-gated electrocardiogram-triggered noncontrast SSFP MRA and conventional high-resolution 3D contrast-enhanced MRA (CE-MRA) of the thorax at 1.5 T. Two readers evaluated both datasets for findings, vascular delineation and sharpness (from 0, not visualized to 3, excellent definition), artifacts, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in 14 vascular segments including aorta, supra-aortic, pulmonary, and coronary arteries, and in cardiac chambers. Statistical analysis was performed using Wilcoxon test for vessel delineation, and [kappa] coefficient for interobserver variability. RESULTS: 3D SSFP and CE-MRA were successfully performed in all patients. Scan time for SSFP MRA ranged from 5 to 10 minutes (mean +/- standard deviation, 7 +/- 2 minutes). On SSFP MRA, readers 1 and 2 graded 233 (97.1%) and 234 (97.5%) coronary arterial segments and cardiac chambers, and 275 (91.7%) and 278 (92.7%) noncoronary arterial segments with diagnostic definition (grades 2 and 3) (k = 0.86). On conventional CE-MRA, readers 1 and 2 graded 10 (4.2%) and 12 (5%) coronary arterial segments and cardiac chambers, and 272 (90.7%) and 270 (90%) noncoronary arterial segments with diagnostic definition (grades 2 and 3) (k = 0.89). Segmental visibility was higher for aortic root, pulmonary trunk, proximal coronary arteries, and heart chambers (P < 0.001), and lower for supra-aortic arteries (P < 0.001) on SSFP MRA for each reader. SNR and CNR values were higher for aortic root and aorta on SSFP MRA (P < 0.001 for both). No significant difference existed between SNR and CNR values for the other vascular segments and cardiac chambers on SSFP and CE-MRA (P > 0.05 for all). The 2 readers demonstrated vascular stenosis and dilatation/aneurysm in 7 and 35 segments on both datasets, respectively. CONCLUSION: Noncontrast 3D SSFP MRA with nonselective radiofrequency excitation provides high image quality and sufficient SNR and CNR for confident assessment of cardiac and thoracic vascular diseases including congenital heart diseases. Our results suggest that noncontrast SSFP MRA outperforms CE-MRA in visualization of cardiac chambers, proximal coronary arteries, pulmonary trunk, and aortic root.     

Preoperative evaluation of living renal donors: value of contrast-enhanced 3D magnetic resonance angiography and comparison of three rendering algorithms

The aim of this study was to assess the value of contrast-enhanced three-dimensional MR angiography (CE 3D MRA) in the preoperative assessment of potential living renal donors, and to compare the accuracy for the depiction of the vascular anatomy using three different rendering algorithms. Twenty-three potential living renal donors were examined with CE 3D MRA (TE/TR=1.3 ms/3.7 ms, field of view 260–320×350 mm, 384–448×512 matrix, slab thickness 9.4 cm, 72 partitions, section thickness 1.3 mm, scan time 24 s, 0.1 mmol/kg body weight gadobenate dimeglumine). Magnetic resonance angiography data sets were processed with maximum intensity projection (MIP), volume rendering (VR), and shaded-surface display (SSD) algorithms. The image analysis was performed independently by three MR-experienced radiologists recording the number of renal arteries, the presence of early branching or vascular pathology. The combination of digital subtraction angiography (DSA) and intraoperative findings served as the gold standard for the image analysis. In total, 52 renal arteries were correspondingly observed in 23 patients at DSA and surgery. Other findings were 3 cases of early branching of the renal arteries, 4 cases of arterial stenosis and 1 case of bilateral fibromuscular dysplasia. With MRA source data all 52 renal arteries were correctly identified by all readers, compared with 51 (98.1%), 51–52 (98.1–100%) and 49–50 renal arteries (94.2–96.2%) with the MIP, VR and SSD projections, respectively. Similarly, the sensitivity, specificity and accuracy was highest with the MRA source data followed by MIP, VR and SSD. Time requirements were lowest for the MIP reconstructions and highest for the VR reconstructions. Contrast-enhanced 3D MRA is a reliable, non-invasive tool for the preoperative evaluation of potential living renal donors. Maximum intensity projection is favourable for the processing of 3D MRA data, as it has minimal time and computational requirements, while having similar or superior accuracy for the depiction of vessel anomalies or pathology compared with VR and SSD, respectively. Electronic Publication     

MR angiography of the pedal arteries with gadobenate dimeglumine, a contrast agent with increased relaxivity, and comparison with selective intraarterial DSA

PURPOSE: To compare gadobenate dimeglumine (Gd-BOPTA)-enhanced MR angiography (i.e., contrast-enhanced MRA [CE-MRA]) of the pedal vasculature with selective digital subtraction angiography (DSA) in patients with peripheral arterial occlusive disease (PAOD). MATERIALS AND METHODS: A total of 22 patients with PAOD were prospectively examined at 1.5T. For contrast enhancement, 0.1 mmol/kg body weight of Gd-BOPTA were applied. MRA consisted of dynamic imaging with acquisition of six consecutive data sets. Acquisition time for each data set was 24 seconds, voxel size was 1.0 x 1.0 x 1.3 mm(3). A total of 20 out of 22 patient underwent selective DSA, two patients fine-needle DSA. DSA and MRA were performed within seven days. Image analysis was independently done by two observers with assessment of overall image quality, motion artifacts, detection of patent vessel segments of the distal calf and pedal vessels, and the number of patent metatarsal arteries. After four weeks, a consensus reading of DSA images was done. A second consensus reading of CE-MRA was performed after a further six weeks. RESULTS: Consensus readings of MRA and DSA revealed higher image quality and fewer motion artifacts for MRA (P = 0.021 and P = 0.008, respectively, sign test); interobserver agreement was good (kappa = 0.78) for image quality, and moderate (kappa = 0.46) for motion artifacts. There were no differences between CE-MRA and DSA in detecting patent vessel segments with a high degree of agreement (kappa = 0.89), and interobserver agreement for MRA was substantial (kappa = 0.89). Significantly more vessels were assessed as partially occluded on DSA than on CE-MRA (P = 0.004). There was a good agreement between DSA and CE-MRA for assessment of relevant vessel stenosis (kappa = 0.61); interobserver agreement for MRA was good (kappa = 0.65). CE-MRA detected significantly more patent metatarsal arteries than did DSA (P < 0.001). CONCLUSION: Gd-BOPTA-enhanced MRA is comparable to DSA for assessment of the pedal vasculature, and is able to delineate significantly more patent vessels without segmental occlusions and more metatarsal arteries than selective DSA.     

Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis

Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiography (MRA) for the diagnosis of RAS. Sixty-two patients with secondary hypertension were enrolled in the study. All patients had conventional renal angiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 °, field of view 36 × 36 cm, matrix 246 × 256, 1 excitation). Gadolinium 0.3 mmol/kg was administered and 60 1.5-mm-thick partitions were obtained over a duration of 3.5 min. The MRA images were then compared with conventional digital subtraction angiography (DSA) images. Conventional DSA demonstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93 %). Twenty-one renal artery stenoses and four occluded arteries were seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98 %, accuracy of 96 %, positive predictive value of 92 % and negative predictive value of 97 % when compared with conventional DSA. Gadolinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries. Received: 17 March 1998; Revision received: 30 June 1998; Accepted: 28 August 1998     

症状性颅、颈部动脉狭窄在3.0T上的MRA与DSA比较研究

目的前瞻性分析3．0T应用SENSE技术的高分辨率对比增强容积扫描MRA（CEMRA）和3DTOFMRA在临床疑有颅、颈部动脉狭窄性病变患者中的应用价值。方法46例临床怀疑颅、颈部动脉狭窄的患者接受头颅MRI平扫、头颅3DTOFMRA和颈部CEMRA检查。动脉狭窄的程度与DSA检查结果进行相关性比较。结果MRA显示各段颅、颈部动脉狭窄的不同程度和DSA检查显著相关（Rs=0．97,P〈0．01）。以DSA结果为金标准,狭窄程度超过50％者MRA诊断灵敏度为100％,特异度为99．4％、准确率为99．4％。结论3．0T的3DTOFMRA和高分辨率CEMRA检查能可靠和有效地评价颅、颈部动脉狭窄性病变,可作为DSA术前必要的检查技术,或可替代传统DSA诊断性检查。     

Noncontrast‐enhanced four‐dimensional MR angiography for the evaluation of cerebral arteriovenous malformation: A preliminary trial

Purpose:

To prospectively evaluate noncontrast‐enhanced (NCE), time resolved, four‐dimensional (4D) magnetic resonance angiography (MRA) for assessment of cerebral arteriovenous malformation (AVM), with intraarterial digital subtraction angiography (DSA) performed as the reference standard.

Materials and Methods:

Fifteen patients (ten men, five women; age range 2–59 years, mean 29.4 years) with 15 untreated cerebral AVMs comprised the study population. NCE 4D MRA was performed on a 3.0 T MR scanner. MR images were reviewed by two independent readers and compared with DSA with respect to arterial feeders, nidus size, and venous drainage. Kappa coefficients of concordance were computed to determine the interobserver and intermodality agreements for the depiction of arterial feeders, nidus, and venous drainage between the two techniques.

Results:

Fifteen AVMs detected in DSA were visualized in NCE 4D MRA. Intermodality agreements were excellent for the arterial feeders (K = 0.918, P = 0.000), good for the nidus size (K = 0.692, P = 0.000), and moderate for the venous drainage (K = 0.495, P = 0.001).

Conclusion:

NCE 4D MRA is a promising and potentially valuable method for noninvasive assessment of angioarchitecture and hemodynamics of cerebral AVMs. Further improvement of labeling persistence is desirable in order to enhance the depiction of draining veins for AVMs. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.     

Whole-heart coronary magnetic resonance angiography at 3 Tesla in 5 minutes with slow infusion of Gd-BOPTA, a high-relaxivity clinical contrast agent.

T(1)-shortening contrast agents have been used to improve the depiction of coronary arteries with breath-hold magnetic resonance angiography (MRA). The spatial resolution and coverage are limited by the duration of the arterial phase of the contrast media passage. In this study we investigated the feasibility of acquiring free-breathing, whole-heart coronary MRA during slow infusion of the contrast media (0.3 ml/s) for prolonged blood signal enhancement time. Ultrashort TR (3 ms) and parallel data acquisition were used to allow the whole-heart MRA in approximately 5 min. A newly approved gadolinium (Gd)-based high T(1) relaxivity contrast agent, gadobenate dimeglumine ([Gd-BOPTA](2-)), was used and coronary MRA was performed on a whole-body 3 Tesla (T) system to improve the signal-to-noise ratio (SNR). Results from eight volunteers demonstrate that this coronary MRA method is capable of imaging the whole heart in 4.5 +/- 0.6 min. Major coronary arteries are well depicted with high SNR (42.4 +/- 12.5) and contrast-to-noise ratio (CNR; 27.1 +/- 7.6).     

肾动脉狭窄的三维增强磁共振血管成像诊断

目的:评价高分辨力三维增强磁共振血管成像术(3DCEMRA)对肾动脉狭窄的显示准确性。方法:对30例临床诊断或怀疑肾动脉狭窄患者进行高分辨力肾动脉3DCEMRA检查,分析所有患者的肾动脉和副肾动脉显示质量和病变显示情况,并与DSA做对照。结果:3DCEMRA显示了30例患者总共59支肾动脉主干(1例为单支移植肾动脉),显示率为100%。3DCEMRA显示4支副肾动脉,显示率100%。肾动脉段级分支的显示率为49%。所有病例在动脉显示区域内静脉均未显影或显影淡,对诊断不构成影响。DSA共显示59支肾动脉主干和4支副肾动脉(以63支计算),59支主干中2支闭塞,8支重度狭窄,11支中度狭窄,10支轻度狭窄,28支肾动脉主干和4支副肾动脉都正常。3DCEMRA除把2支轻度狭窄估为中度狭窄,1支中度狭窄估为重度狭窄外,其它结果都同DSA一致,故3DCEMRA显示肾动脉主干和副肾动脉狭窄程度超过50%的有血液动力学意义的明显狭窄的敏感性和特异性分别为100%和95%,阳性预测值为91%,阴性预测值为100%。结论:高分辨力肾动脉3DCEMRA能准确检出肾动脉主干和副肾动脉狭窄,并能较好判断其狭窄程度。     

Comparison of high-resolution contrast-enhanced 3D MRA with digital subtraction angiography in the evaluation of hepatic arterial anatomy

AIM: To evaluate the validity of high-resolution contrast-enhanced three-dimensional magnetic resonance angiography (MRA) in defining hepatic arterial anatomy and to compare this with digital subtraction angiography (DSA). MATERIALS AND METHODS: MRA and DSA were performed in 30 patients. MRA was performed with breath-hold, gadolinium-enhanced, three-dimensional, fast low-angle shot sequence with a 512 pixel matrix. MRA was compared with DSA in terms of image quality and depiction of hepatic arterial anatomy. The agreement in image quality between MRA and DSA was determined with the kappa statistic. RESULTS: With respect to image quality, there was excellent or good correlation between MRA and DSA for the common hepatic artery (kappa=0.85), proper hepatic artery (kappa=0.72), gastroduodenal artery (kappa=0.70), left hepatic artery (kappa=0.49), left gastric artery (kappa=0.50), splenic artery (kappa=0.84), and superior mesenteric artery (kappa=0.88). Poor correlation was found for the right hepatic artery (kappa=0.18) and right gastric artery (kappa=0.38). With regard to hepatic arterial anatomy, MRA correlated correctly with DSA in 28 of the 29 cases, i.e. 97% of patients. CONCLUSION: MRA is a useful technique for the evaluation of the hepatic artery, and for the vast majority of patients, MRA can replace intra-arterial DSA.     

Magnetic resonance angiography in suspected cerebral vasculitis

The purpose of this study was to determine the technical capacity and diagnostic accuracy of 3D time-of-flight magnetic resonance angiography (MRA) in suspected cerebral vasculitis in a retrospective analysis of MRA and digital subtraction angiography (DSA) in 14 young patients with clinical and/or radiological suspicion of cerebral vasculitis. A total of nine arteries were evaluated in each patient. Consensus review of DSA by three observers was the reference standard. The sensitivity for detecting a stenosis varied from 62 to 79% for MRA and from 76 to 94% for DSA, depending on the observer. The specificity for detecting a stenosis varied from 83 to 87% for MRA and from 83 to 97% for DSA. Using the criterion more than two stenoses in at least two separate vascular distributions to consider the examination as being true positive, the false-positive rates for MRA and DSA were comparable. MRA plays a role as the first angiographical examination in the diagnostic work-up of suspected cerebral vasculitis. When more than two stenoses in at least two separate vascular distributions are depicted on MRA, DSA is not expected to add a significant diagnostic contribution in a patient with suspected cerebral vasculitis. DSA remains necessary when MRA is normal or when less than three stenoses are seen.     

Gadobutrol-enhanced moving-table magnetic resonance angiography in patients with peripheral vascular disease: a prospective,multi-centre blinded comparison with digital subtraction angiography

The purpose of this study was to compare moving-table three-dimensional contrast-enhanced magnetic resonance angiography (CE MRA), using 1.0-mol gadobutrol, with intra-arterial digital subtraction angiography (i.a. DSA) for evaluation of pelvic and peripheral arteries in patients with peripheral arterial occlusive disease. A total of 203 patients were examined in a prospective, multi-centre study at 1.0/1.5 T. Ten vessel segments of one leg were evaluated on-site and by three independent blinded reviewers off-site. One hundred eighty-two patients were evaluable in blinded reading. For pelvis and thigh, there was statistically significant diagnostic agreement between CE MRA and i.a. DSA on-site (94%) and off-site (86-88%). Overall, for detection of clinically significant stenoses, 93% sensitivity and 90% specificity were achieved in on-site evaluation, with 71-76 and 87-93% off-site; for detection of occlusion, sensitivity and specificity on-site were 91 and 97%, with 75-82 and 94-98% off-site. Evaluation was more sensitive on-site than off-site for detection of stenoses and occlusion, whereas specificity was similar. The CE MRA with 1.0-mol gadobutrol gave results comparable to those of i.a. DSA for the larger arteries of pelvis and thigh. Results for calf arteries were compromised by spatial resolution and technical limitations.     

Conventional digital subtraction x-ray angiography versus magnetic resonance angiography in the evaluation of carotid disease: patient satisfaction and preferences

AIM: To compare conventional digital subtraction x-ray angiography (DSA) and contrast-enhanced magnetic resonance angiography (MRA) of the carotid arteries in terms of patient satisfaction and preferences. METHODS: One hundred and sixty-seven patients with symptomatic carotid artery disease, who underwent both DSA and MRA, were prospectively recruited in this study. Patients' perceptions of each method were assessed by the use of a questionnaire after each procedure. Main outcome measures were anxiety, pain, satisfaction rate and patient preferences. RESULTS: DSA generated more anxiety and pain during the procedure, but the severity of these ill-effects was mild. Satisfaction rates for each method were similar. More patients were, however, willing to have a repeat MRA compared with DSA (67 versus 41%). The majority of patients (62%) preferred MRA over DSA (31%). The shorter MRA imaging time was found to be a significant factor in patients' acceptance of the technique. The main reasons cited by patients for their dislike of a particular procedure was noise and claustrophobia for MRA and invasiveness, pain and post-procedural bed rest for DSA. CONCLUSIONS: MRA is the method that is preferred by the majority of patients, although the actual disutility of DSA may be small. Assuming equal diagnostic accuracy, our data supports replacement of DSA by MRA for routine carotid imaging.     

Contrast-enhanced three-dimensional MR angiography in the assessment of subclavian artery diseases

The purpose of this prospective study was to determine the potential diagnostic value of 3D breath-hold contrast-enhanced MRA (CEMRA) in the evaluation of subclavian artery pathology, and to compare CEMRA and digital subtraction angiography (DSA) findings. The study group included 50 patients with suspicion of subclavian artery pathology: 40 suspected steno-occlusive disease and 10 different vascular anomalies. The MRA examinations were performed on a 1.5-T system using fast 3D sequences. A fixed dose of 40 ml Gd-DTPA was administered at 2 ml/s after previous bolus tracking. Images were analyzed to assess: subclavian depiction; luminal changes; collateral branches; and feeders of arterial venous malformations (AVM). A multireader blinded fashion was used. The CEMRA revealed an optimal agreement with DSA findings in the different types of diseases. Sensitivity and specificity were 90 and 95 %, respectively, in detecting steno-occlusive disease (including functional and arteritic stenoses), and 100 and 100 %, respectively, in cases of vascular anomalies (dilation, kinking, anomalous origin and AVM). Contrast-enhanced MRA can be proposed as a non-invasive, robust technique for imaging subclavian pathologies with high diagnostic performance. Received: 18 May 1999; Revised: 5 January 2000; Accepted: 27 March 2000     

Assessment of the uterine artery before uterine arterial embolization: comparison of unenhanced 3D water-excitation sensitivity-encoding time-of-flight (WEST) and gadolinium-enhanced 3D sensitivity-encoding water-excitation multishot echo-planar (SWEEP) MR angiography

PURPOSE: To compare unenhanced 3D water-excitation sensitivity-encoding time-of-flight (WEST) and gadolinium-enhanced 3D sensitivity-encoding water-excitation multishot echo-planar (SWEEP) MR angiography (MRA) with regard to conspicuity of uterine arteries in correlation with digital subtraction angiography (DSA). MATERIALS AND METHODS: Eleven consecutive patients with symptomatic uterine fibroids underwent 2 types of MRA before uterine arterial embolization (UAE). From these MRA an interventional radiologist predicted the optimal degrees for oblique DSA projections to reveal uterine arterial origins. Qualitatively, three independent observers reviewed two types of MRA assessing the conspicuity of uterine arterial origins and descending portions using a 3-point scale. Quantitatively, the visualized uterine arteries were measured from their orifice to the end of their descending portions. RESULTS: At UAE, knowing the optimal degrees from MRA, the uterine arterial origins were clearly visualized on all first oblique DSA projections. Mean conspicuity levels of the uterine arterial origins and descending portions were significantly higher and mean length of the visualized uterine arteries was significantly longer for unenhanced WEST MRA than for gadolinium-enhanced SWEEP MRA. CONCLUSION: Unenhanced 3D-WEST MRA was superior to gadolinium-enhanced 3D-SWEEP MRA in demonstrating uterine arteries. The optimal degrees for DSA projections to reveal uterine arterial origins could be accurately predicted using this noninvasive technique.     

Peripheral arterial occlusive disease: role of MR angiography

PURPOSE: Magnetic resonance angiography (MRA) has recently become instrumental in the diagnosis of arterial disease in various body districts and is gaining an increasingly important role in the study of peripheral vascularisation. The aim of our study was to evaluate the reliability of MRA using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: Between November 2003 and August 2004, 30 patients with known peripheral arterial disease were studied by MRA and DSA. MRA was performed with a Philips Intera 1.5 T, with acquisitions from the coeliac trunk to the feet. For acquisitions of the feet and ankles we used unenhanced time-of-flight (TOF) sequences with a head coil. The angiographic sequence was acquired in three volumes of 40-45 cm after administration of paramagnetic contrast material. RESULTS: In the patients with peripheral arterial disease, the technique provided a precise evaluation of the stenosis (mild, moderate, severe) or obstruction of the peripheral district as well as the detection of other diseases, such as stenosis of the renal arteries or aneurysms. CONCLUSIONS: Total-body three-dimensional (3D) MRA allows a fast, safe, and accurate assessment of the arterial system in patients with arteriosclerosis and can be considered an alternative to DSA in the management of patients with steno-obstructive disease of the peripheral arteries.     

Comparison of magnetic resonance angiography and digital angiography of the epiaortic vessels

Atheromasic lesions and other pathologic conditions of the arterial vessels of the neck are the most frequent causes of cerebrovascular disease. Diagnostic imaging currently employs digital subtraction angiography (DSA), Doppler, and color-Doppler US to study these conditions. Digital subtraction intraarterial angiography (DSAA) can provide both an early diagnosis and an accurate preoperative depiction of neck vessels; however, in spite of its effective value, it still remains an invasive technique. Magnetic Resonance angiography (angio-MR) is the latest technique allowing the depiction of neck vessels morphology. It shares with digital angiography the capability of supplying spatial depiction of all the examined vascular structures, and with US its noninvasiveness. The authors investigated angio-MR capabilities in providing accurate and detailed images of neck arteries; the images were then compared with DSA ones. Thirty patients with cerebrovascular diseases were studied. MR imaging was performed with a 1.5 T unit with a dedicated coil, and gradient-echo sequences were employed. Refocused sequences for flow were acquired on both the coronal and the sagittal planes, with the following parameters: TR 40, TE 10, flip angle 25 degrees, acquisition volumes 80-35 mm, 64-15 frames. Digital angiography demonstrated 101 vascular lesions: 27 slight stenoses (less than 30%), 19 mild stenoses (31-70%), 12 severe stenoses (71-99%), 7 occlusions, 14 coilings, 7 kinkings, and 15 hypoplasias of vertebral artery. In slight stenoses, angio-MR underestimated the condition in 11/27 patients. In mild and severe stenoses, as well as in occlusive diseases, angio-MR tended to overestimate the condition. In coiling, kinking, and hypoplasia, angio-MR yielded the same results as DSA.     

三维动态增强MR血管造影对颅内动脉瘤的诊断价值

目的 评价三维动态增强磁共振血管造影(3D DCE-MRA)在颅内动脉瘤诊断中的价值。方法 对54例高度怀疑有颅内动脉瘤的病人行3D DCE-MRA检查，随后行DSA造影及可行的血管内栓塞治疗。3D DCE-MRA用超快速三维梯度回波序列(3D FISP)(钆喷替酸葡甲胺0．2mmol／kg,1次扫描时间10s)，工作站上三维重建，比较3D DCE-MRA及常规DSA在显示动脉瘤、瘤颈及与载瘤动脉关系上的优劣，及对血管内栓塞治疗的价值。结果 39例脑动脉瘤患者共45个动脉瘤，3D DCE-MRA对动脉瘤的敏感度为96％，特异度73％，准确度90％。3D DCE-MRA对动脉瘤细节及瘤颈的显示明显优于常规DSA，尤其是颈内动脉海绵窦部及椎动脉近小脑后下动脉的动脉瘤，可指导DSA显示动脉瘤方向及预先制定治疗方案。但对周边部及动脉分岔处小动脉瘤的诊断应谨慎。结论3D DCE-MRA能无创有效地诊断颅内动脉瘤，所提供的三维信息对治疗方案的制定具有极大帮助。当诊断有怀疑时，应结合DSA检查。