Three-dimensional Contrast-enhanced Magnetic Resonance Angiography Research Articles

The diagnostic performance of three-dimensional contrast-enhanced magnetic resonance angiography in demonstrating renal vasculature in patients with suspected renovascular hypertension

Amac: Calismamizin amaci, digital subtraction angiography (DSA) teknigini referans metod alarak, uc boyutlu kontrastli manyetik rezonans anjiyografi (3D CE-MRA) tekniginin, renal arter stenozu (RAS) tanisindaki ve segmental ve aksesuar renal arter goruntulemesindeki degerini saptamak idi. Gerec ve Yontem: Yirmi bes hastaya 3D CE-MRA ve DSA tetkikleri uygulandi. CE-MRA tekniginin RAS tanisindaki sensitivite, spesifisite ve pozitif ve negatif kestirim degerleri ile teknigin segmental ve aksesuar renal arter goruntulemedeki sensitivite degerleri hesaplandi. Bulgular: RAS tanisinda CE-MRA tekniginin sensitivite, spesifisite, pozitif ve negatif kestirim degerleri, ayni sira ile; %100, %97,8, %87,5, ve %100 olarak hesaplandi. Teknigin segmental ve aksesuar renal arter goruntulemedeki sensitivite degerlerinin, ayni sira ile; %58 ve %91,7 oldugu saptandi. Sonuc: 3D CE-MRA tekniginin, sadece renal arter stenozu tanisinda degil, aksesuar arterlerin goruntulemesinde de guvenilir oldugu saptandi. Ancak calismamizin sonuclarina gore, teknigin segmental arter goruntulemesindeki degeri sinirlidir.

Comparison of Non-Contrast Magnetic Resonance Angiography Using Inflow Inversion Recovery (Inhance) Technique and Contrast-Enhanced Magnetic Resonance Angiography in the Assessment of Renal Arteries of Patients with Hypertension

Background: Renal artery stenosis can cause renovascular hypertension manifesting clinically as high blood pressure. Objectives: In this study, we determined the efficiency of non-contrast magnetic resonance angiography (NC-MRA) using the inflow inversion recovery (inhance) method in the evaluation of renal arteries of hypertensive patients. Patients and Methods: Three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CE-MRA) and NC-MRA were used to prospectively evaluate 66 patients diagnosed with hypertension. 3D CE-MRA and digital substractional angiography served as the gold standards. Image quality, number of main/accessory renal arteries, and main renal artery diameters were assessed. Statistical analyses were based on paired-t tests and intra-class correlation coefficients. Results: Of the 126 main renal and 12 accessory renal arteries reviewed in this study, NC-MRA overall image quality was good or excellent in more than 89.5%. An image quality of 94% was recorded for both left and right sides with CE-MRA. The differences between the 3D CE-MRA and NC-MRA readings for the renal artery ostium and proximal, medial, and distal segment diameters were not significant (P > 0.05). Inter-reader agreement regarding all segments was excellent. 3D CE-MRA was superior to NC-MRA in assessing accessory renal arteries (detection ratio using NC-MRA: 7/12, 58%). Conclusion: NC-MRA using the inhance method to image the anatomy of the renal artery provides an alternative to CE-MRA in patients with hypertension.

Aortic Volumetry at Contrast-Enhanced Magnetic Resonance Angiography: Feasibility as a Sensitive Method for Monitoring Bicuspid Aortic Valve Aortopathy.

Bicuspid aortic valve patients can develop thoracic aortic aneurysms and therefore require serial imaging to monitor aortic growth. This study investigates the reliability of contrast-enhanced magnetic resonance angiography (CEMRA) volumetry compared with 2-dimensional diameter measurements to identify thoracic aortic aneurysm growth. A retrospective, institutional review board-approved, and Health Insurance Portability and Accountability Act-compliant study was conducted on 20 bicuspid aortic valve patients (45 ± 8.9 years, 20% women) who underwent serial CEMRA with a minimum imaging follow-up of 11 months. Magnetic resonance imaging was performed at 1.5 T with electrocardiogram-gated, time-resolved CEMRA. Independent observers measured the diameter at the sinuses of Valsalva (SOVs) and mid ascending aorta (MAA) as well as ascending aorta volume between the aortic valve annulus and innominate branch. Intraobserver/interobserver coefficient of variation (COV) and intraclass correlation coefficient (ICC) were computed to assess reliability. Growth rates were calculated and assessed by Student t test (P < 0.05, significant). The diameter of maximal growth (DMG), defined as the diameter at SOV or MAA with the faster growth rate, was recorded. The mean time of follow-up was 2.6 ± 0.82 years. The intraobserver COV was 0.01 for SOV, 0.02 for MAA, and 0.02 for volume (interobserver COV: 0.02, 0.03, 0.04, respectively). The ICC was 0.83 for SOV, 0.86 for MAA, 0.90 for DMG, and 0.95 for volume. Average aortic measurements at baseline and (follow-up) were 42 ± 3 mm (42 ± 3 mm, P = 0.11) at SOV, 46 ± 4 mm (47 ± 4 mm, P < 0.05) at MAA, and 130 ± 23 mL (144 ± 24 mL, P < 0.05). Average size changes were 0.2 ± 0.6 mm/y (1% ± 2%) at SOV, 0.5 ± 0.8 mm/y (1% ± 2%) at MAA, 0.7 ± 0.7 mm/y (2% ± 2%) at DMG, and 6 ± 3 mL/y (4% ± 3%) with volumetry. Three-dimensional CEMRA volumetry exhibited a larger effect when examining percentage growth, a better ICC, and a marginally lower COV. Volumetry may be more sensitive to growth and possibly less affected by error than diameter measurements.

Three-dimensional contrast-enhanced magnetic resonance angiography for anterolateral thigh flap outlining: A retrospective case series of 68 patients.

Flap transfer is increasingly used for repairing limb defects secondary to trauma or tumor, and appropriate preoperative planning plays a critical role. The present study aimed to examine the use of three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CE-MRA) in evaluating the blood supply distribution and perforating branch pattern of anterolateral thigh (ALT) flaps. Bilateral donor lower limbs were scanned in 68 patients (136 limbs) using a Siemens Avanto 1.5 T magnetic resonance imaging scanner with a 3D fast low-angle shot sequence, following the thin-slab maximum intensity projection (TS-MIP) technique. The lateral femoral circumflex artery (LFCA) was visualized in all patients: 101 limbs (101/136, 74.3%) were type I; 20 limbs (20/136, 14.7%) were type II; 3 limbs (3/136, 2.2%) were type III; and 12 limbs (12/136, 8.8%) were type IV. Tertiary branches were identified in 94 limbs (94/136, 69.1%). Donor flaps were outlined according to MRA TS-MIP findings in 4 patients. All flaps survived uneventfully following the transfer. In donor flap outlining, 3D CE-MRA with the TS-MIP technique allowed an accurate, direct visualization of the branching pattern and distribution profile of the LFCA supplying the ALT flap.

Renal Arteriovenous Shunts: Clinical Features, Imaging Appearance, and Transcatheter Embolization Based on Angioarchitecture.

Renal arteriovenous (AV) shunt, a rare pathologic condition, is divided into two categories, traumatic and nontraumatic, and can cause massive hematuria, retroperitoneal hemorrhage, pain, and high-output heart failure. Although transcatheter embolization is a less-invasive and effective treatment option, it has a potential risk of complications, including renal infarction and pulmonary embolism, and a potential risk of recanalization. The successful embolization of renal AV shunt requires a complete occlusion of the shunted vessel while preventing the migration of embolic materials and preserving normal renal arterial branches, which depends on the selection of adequate techniques and embolic materials for individual cases, based on the etiology and imaging angioarchitecture of the renal AV shunts. A classification of AV malformations in the extremities and body trunk could precisely correspond with the angioarchitecture of the nontraumatic renal AV shunts. The selection of techniques and choice of adequate embolic materials such as coils, vascular plugs, and liquid materials are determined on the basis of cause (eg, traumatic vs nontraumatic), the classification, and some other aspects of the angioarchitecture of renal AV shunts, including the flow and size of the fistulas, multiplicity of the feeders, and endovascular accessibility to the target lesions. Computed tomographic angiography and selective digital subtraction angiography can provide precise information about the angioarchitecture of renal AV shunts before treatment. Color Doppler ultrasonography and time-resolved three-dimensional contrast-enhanced magnetic resonance angiography represent useful tools for screening and follow-up examinations of renal AV shunts after embolization. In this article, the classifications, imaging features, and an endovascular treatment strategy based on the angioarchitecture of renal AV shunts are described.

Follow-up of true visceral artery aneurysm after coil embolization by three-dimensional contrast-enhanced MR angiography

We aimed to evaluate the outcomes of coil embolization of true visceral artery aneurysms by three-dimensional contrast-enhanced magnetic resonance (MR) angiography. We used three-dimensional contrast-enhanced MR angiography, which included source images, to evaluate 23 patients (mean age, 60 years; range, 28-83 years) with true visceral artery aneurysms (splenic, n=15; hepatic, n=2; gastroduodenal, n=2; celiac, n=2; pancreaticoduodenal, n=1; gastroepiploic, n=1) who underwent coil embolization. Angiographic aneurysmal occlusion was revealed in all cases. Follow-up MR angiography was conducted with either a 1.5 or 3 Tesla system 3-25 months (mean, 18 months) after embolization. MR angiography was evaluated for aneurysmal occlusion, hemodynamic status, and complications. Complete aneurysmal occlusion was determined in 22 patients (96%) on follow-up MR angiography (mean follow-up period, 18 months). Neck recanalization, which was observed at nine and 20 months after embolization, was confirmed in one of eight patients (13%) using a neck preservation technique. In this patient, a small neck recanalization covered by a coil mass was demonstrated. The complete hemodynamic status after embolization was determined in 21 patients (91%); the visualization of several collateral vessels, such as short gastric arteries, after parent artery occlusion was poor compared with that seen on digital subtraction angiography in the remaining two patients (9%). An asymptomatic localized splenic infarction was confirmed in one patient (4%). Our study presents the follow-up results from three-dimensional contrast-enhanced MR angiography, which confirmed neck recanalization, the approximate hemodynamic status, and complications. This effective and less invasive method may be suitable for serial follow-up after coil embolization of true visceral aneurysms.

Thrombosed Large Distal Posterior Inferior Cerebellar Artery Aneurysm Mimicking an Infratentorial Ependymoma

Large or giant intracranial aneurysms can simulate brain tumors clinically and radiologically by virtue of their progressive mass effect. Unlike aneurysms from alternative locations, those arising from the distal posterior inferior cerebellar artery (PICA) are uncommon. We report a patient who experienced progressive hemiparesis with magnetic resonance imaging findings suggestive of an infratentorial ependymoma. Intraoperatively, a thrombosed large aneurysm of the distal PICA was unexpectedly encountered. The aneurysm was clipped and the patient did not develop any permanent neurological deficit. This case illustrates the radiological nuances of large aneurysms and infratentorial ependymomas. Three-dimensional contrast-enhanced magnetic resonance angiography can be falsely negative and the importance of the “target” sign is emphasized. One should be cognizant of this possible diagnosis for patients with midline fourth ventricular lesions in order to reduce surgical risk.

Contrast-Enhanced Magnetic Resonance Angiography in the Early Period After Kidney Transplantation

Our objective was to evaluate the usefulness of three-dimensional (3-D) contrast-enhanced (CE) magnetic resonance angiography (MRA) to assess renal parenchyma, arterial inflow stenosis, and peritransplant fluid collections in the early period after kidney transplantation (KT). Between January 2010 and April 2011, we examined a consecutive series of 144 renal transplants using 3-D CE MRA at 14 days after KT. MRA showed parenchyma infarctions (n = 17, 11.8%), arterial inflow stenoses (n = 23, 16%), lymphoceles (n = 14, 9.7%), and hematomas (n = 6, 4.2%). The degree of renal transplant artery inflow stenosis was graded qualitatively based on diameter criterion; <50% = mild, 50% to 70% = moderate, and >70% = severe in 10 (6.9%), 5 (3.5%), and 8 (5.6%) subjects, respectively. The study recipients were divided into 3 groups according to the degree of renal artery inflow stenosis (group I: normal; group II: mild and moderate, <70%; group III: severe, >70%). Among group III patients who underwent digital subtraction angiography, 5 had percutaneous transluminal angioplasty or stenting performed after 1 month. Their mean resume creatinine levels at 1, 6, and 12 months after transplantation were not significantly different from those in the other groups (P = .391, .447, .110). The prevalence of graft loss (n = 2) was high in group III (P = .012), although the frequency of acute rejection episodes was not different among the groups (P = .890). The incidences of renal parenchyma infarction, peritransplant fluid collection and arterial inflow stenosis were unexpectedly high in the early period after KT. Thus, 3-D CE MRA provided a rapid global assessment of the renal parenchyma, transplant arterial system, and peritransplant fluid collection that can be helpful to detect or exclude many causes of renal transplant dysfunction.

Hepatic artery aneurysm: incidental diagnosis with abdominal ultrasonography and treatment by coil embolization

Hepatic artery aneurysm (HAA) was first reported at autopsy in 1809, represents one fifth of visceral aneurysms and the mortality from spontaneous rupture is high in most of cases. We are reporting a case of an asymptomatic 48-year-old woman with an extrahepatic HAA, diagnosed initially and incidentally with abdominal ultrasonography, confirmed by a three-dimensional contrast-enhanced magnetic resonance imaging and angiography. Endovascular treatment was considered feasible and was successfully treated with coil embolization.

Use of Three-Dimensional MRI-Angiography in Preoperative Evaluation and Postoperative Management of Hemangiomas of Head and Neck Region

Hemangiomas (proliferating endothelial tumors) are the most common benign tumors of infancy. Most often hemangiomas are self-regressing lesions without any treatment. Approximately 10% of hemangiomas cause complications such as major ulceration/destruction, distortion of involved tissues, and obstruction of a vital structure. When the situation becomes complicated, there are different treatment alternatives, ranging from systemic or local corticosteroid use to surgery. Sclerotherapy using intralesional polidocanol (Aethoxysklerol) injection may be used before surgery to decrease blood loss or when a vital structure of the face is in danger because of sudden increase in size of a surrounding hemangioma. Before any kind of treatment for both hemangiomas and vascular malformations, preoperative diagnosis and anatomic position of the lesion must be documented thoroughly. With the help of magnetic resonance imaging, tridimensional vascular pattern of such lesions can be shown successfully. We used three-dimensional contrast-enhanced time-resolved magnetic resonance angiography to detect the changes of lesions for 2 children who have large hemangiomas on their faces, before and after sclerotherapy with polidocanol injection. The findings of three-dimensional magnetic resonance imaging studies help to better assess the success rate of treatment not only for us as the physicians but also for the parents of these children who cannot understand anything with standard two-dimensional radiologic imaging.

Diagnosis of Budd–Chiari syndrome: three-dimensional dynamic contrast enhanced magnetic resonance angiography

To investigate the characteristics and diagnostic value of three-dimensional contrast-enhanced magnetic resonance angiography (3D CE-MRA) in the diagnosis of Budd-Chiari syndrome (BCS). One hundred thirty-three BCS patients underwent 3D CE-MRA, 64 patients had primary BCS, and 69 had secondary BCS. Fifty five cases (41.4%) showed a segmental stenosis of the inferior vena cava, 9 cases (6.8%) a membranous obstruction of the inferior vena cava, 5 cases (3.8%) an unobstructed inferior vena cava and hepatic veno-occlusive condition, 16 cases (12.0%) an inferior vena cava stenosis and hepatic veno-occlusive disease, and 48 cases (36.1%) an intraluminal filling defect in the inferior vena cava. In 52 cases (39.1%), collateral blood vessels were formed, with deep, medium, and shallow portal veins and intrahepatic collateral veins in 88 groups. Among these, 41 (46.6%) had deep venous collateral channels, 24 (27.3%) had medium venous collateral channels, 9 (10.2%) had superficial venous collateral channels, 5 (5.7%) had portal vein collateral channels, and 9 (10.2%) had intrahepatic venous collateral channels. 3D CE-MRA is important in the clinical diagnosis and treatment planning of BCS and displays hepatic veins, the inferior vena cava system, and collateral vessels.

Three-dimensional MRA Study of the Normal Canine Thorax: MIP Sections and Volume Rendering

The purpose of this study was to investigate the feasibility of three-dimensional contrast-enhanced magnetic resonance angiography (3D-CE-MRA) for the non-invasive anatomical evaluation of the thoracic vasculature in five normal Beagles. After intravenous gadolinium administration and a cardio-respiratory gating protocol, fast 3D gradient echo pulse sequence MRA was performed employing a 1.5 Tesla magnet and a human thorax coil. Three-dimensional vascular software was applied. Sagittal, transverse and dorsal maximum intensity projection (MIP) sections and volume rendering (VR) images were obtained and labelled. Anatomical literature, dissections and gross sections were employed to assist the identification of the vascular structures. With improvements in scanner technology, MIP sections and VR images are a promising, non-invasive and accurate method of evaluating the canine thoracic vasculature. Images provide a reference material for clinical studies of the canine thorax for radiologist-surgeon teamwork assessment and also encourage the development of this technique in veterinary medicine.

Efficacy Of Three-dimensional Contrast-enhanced Magnetic Resonance Angiography (3d Ce-mra) In The Diagnosis Of Thoracic Outlet Syndrome

Objective: The purpose of this study is to evaluate the effect of various upper extremity positions (adduction-abduction) on vascular structures in contrast-enhanced three-dimensional MR angiographic studies performed in patients with thoracic outlet syndrome. Materials and Methods: Twenty-two consecutive patients with clinical symptoms of neurovascular thoracic outlet syndrome were examined by 1.0 T MR unit. Examinations were studied by three-dimensional contrast-enhanced MR angiography with the arms positioned in abduction and adduction in the same patients. Results: In twenty-one of 44 subclavian arteries, impingement or stenosis with different degrees were found. Majority of lesions were localized in the costoclavicular region. Venous phase sequences of contrast-enhanced MR angiography showed compression of the subclavian vein in the 17 areas. Conclusion: Thoracic outlet syndrome remains controversial in both diagnosis and treatment, particulary in patients with no muscle atrophy, hand ischemia findings or venous stasis symptoms. Three-dimensional contrast-enhanced MR angiography is noninvasive and requires neither ionizing radiation nor administration of iodinated contrast material- and may be used to diagnose early compression findings and stenosis of the subclavian vessels.

Measuring aortic diameter with different MR techniques: Comparison of three‐dimensional (3D) navigated steady‐state free‐precession (SSFP), 3D contrast‐enhanced magnetic resonance angiography (CE‐MRA), 2D T2 black blood, and 2D cine SSFP

To compare nongated three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CE-MRA) with 3D-navigated cardiac-gated steady-state free-precession bright blood (3D-nav SSFP) and noncontrast 2D techniques for ascending aorta dimension measurements. Twenty-five clinical exams were reviewed to evaluate the ascending aorta at 1.5T using: breathhold cine bright blood (SSFP), cardiac-triggered T2 black blood (T2 BB), axial 3D-nav SSFP, and nongated 3D CE-MRA. Three radiologists independently measured aortic size at three specified locations for each sequence. Means, SDs, interobserver correlation, and vessel edge sharpness were statistically evaluated. Measurements were greatest for 3D-nav SSFP and 3D CE-MRA and smallest for T2 BB. There was no significant difference between 3D-nav SSFP and 3D CE-MRA (P = 0.43-0.86), but significance was observed comparing T2 BB to all sequences. Interobserver agreement was uniformly >0.9, with T2 BB best, followed closely by 3D-nav SSFP and 2D cine SSFP, and 3D CE-MRA being the worst. Edge sharpness was significantly poorer for 3D CE-MRA compared to the other sequences (P < 0.001). If diameter measurements are the main clinical concern, 3D-nav SSFP appears to be the best choice, as it has a sharp edge profile, is easy to acquire and postprocess, and shows very good interobserver correlation.

Peripheral Vasculature: High-Temporal- and High-Spatial-Resolution Three-dimensional Contrast-enhanced MR Angiography

To prospectively evaluate the feasibility of performing high-spatial-resolution (1-mm isotropic) time-resolved three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiography of the peripheral vasculature with Cartesian acquisition with projection-reconstruction-like sampling (CAPR) and eightfold accelerated two-dimensional (2D) sensitivity encoding (SENSE). All studies were approved by the institutional review board and were HIPAA compliant; written informed consent was obtained from all participants. There were 13 volunteers (mean age, 41.9; range, 27-53 years). The CAPR sequence was adapted to provide 1-mm isotropic spatial resolution and a 5-second frame time. Use of different receiver coil element sizes for those placed on the anterior-to-posterior versus left-to-right sides of the field of view reduced signal-to-noise ratio loss due to acceleration. Results from eight volunteers were rated independently by two radiologists according to prominence of artifact, arterial to venous separation, vessel sharpness, continuity of arterial signal intensity in major arteries (anterior and posterior tibial, peroneal), demarcation of origin of major arteries, and overall diagnostic image quality. MR angiographic results in two patients with peripheral vascular disease were compared with their results at computed tomographic angiography. The sequence exhibited no image artifact adversely affecting diagnostic image quality. Temporal resolution was evaluated to be sufficient in all cases, even with known rapid arterial to venous transit. The vessels were graded to have excellent sharpness, continuity, and demarcation of the origins of the major arteries. Distal muscular branches and the communicating and perforating arteries were routinely seen. Excellent diagnostic quality rating was given for 15 (94%) of 16 evaluations. The feasibility of performing high-diagnostic-quality time-resolved 3D contrast-enhanced MR angiography of the peripheral vasculature by using CAPR and eightfold accelerated 2D SENSE has been demonstrated.

A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla.

The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla. The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects. Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of approximately 300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20 degrees-30 degrees. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel. The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.

Bolus shaping of contrast medium to adapt k-space sampling: adjusting injection protocol of magnetic resonance angiography for optimal images in a 3-T system

Purpose To explore the possibility of shaping bolus of contrast medium to adapt k-space sampling to improve image quality in a 3-T system. Materials and Methods Eighty patients suspected of having renal arterial disease or atherosclerosis were divided into four groups and underwent imaging with different high-spatial-resolution three-dimensional contrast-enhanced magnetic resonance angiography (MRA) scanning and injection protocol combinations. A group of 20 patients were injected single-dose contrast medium with a centric view ordering for k-space filling. Another group of 20 patients underwent MRA with double-dose and centric-view ordering. The bolus of contrast medium was shaped by adjusting injection protocol to adapt centric and sequential view ordering of sampling k-space, respectively, for other two groups. Then, the quality of image got with different protocols combination was compared, and the dose of contrast medium used in latter two groups was compared with single- and double-dose prescription basing on body weight. Result Bolus shaped adapting to centric view ordering and sequential view ordering brings more homogeneous vessel signal. Individualized dose is lower than the double dose but higher than the single dose. Dose does not necessarily correlate with body weight. Conclusion Under certain scanning protocol, appropriate shape of contrast medium passing through target vessel leads to higher-quality image and save contrast medium.

Clinical validation of an automated vessel-segmentation software of the extracranial-carotid arteries based on 3D-MRA: A prospective study

To determine the accuracy of automated vessel-segmentation software for vessel-diameter measurements based on three-dimensional contrast-enhanced magnetic resonance angiography (3D-MRA). In 10 patients with high-grade carotid stenosis, automated measurements of both carotid arteries were obtained with 3D-MRA by two independent investigators and compared with manual measurements obtained by digital subtraction angiography (DSA) and 2D maximum-intensity projection (2D-MIP) based on MRA and duplex ultrasonography (US). In 42 patients undergoing carotid endarterectomy (CEA), intraoperative measurements (IOP) were compared with postoperative 3D-MRA and US. Mean interoperator variability was 8% for measurements by DSA and 11% by 2D-MIP, but there was no interoperator variability with the automated 3D-MRA analysis. Good correlations were found between DSA (standard of reference), manual 2D-MIP (rP=0.6) and automated 3D-MRA (rP=0.8). Excellent correlations were found between IOP, 3D-MRA (rP=0.93) and US (rP=0.83). Automated 3D-MRA-based vessel segmentation and quantification result in accurate measurements of extracerebral-vessel dimensions.

Evaluation of Bicuspid Aortic Valve and Aortic Coarctation With 4D Flow Magnetic Resonance Imaging

Time-resolved, 3D, phase-contrast magnetic resonance imaging (4D flow) is an effective means of evaluating dynamic multidirectional blood flow in the thoracic aorta.1 We have used the technique for characterization of abnormal flow features in a 14-year-old boy with aortic coarctation and bicuspid aortic valve (BAV) but without evidence of aortic stenosis or regurgitation. In addition to the expected flow disturbance in the region of the juxtaductal coarctation (Figure 1), we show an unusual flow feature in the ascending aorta that has not been previously reported in this clinical setting and that may be unique to BAV: 2 discrete nested helices of midsystolic blood flow in a nonaneurysmal aorta (Figure 2). Figure 1. Fourteen-year-old boy with BAV and aortic coarctation. A, Three-dimensional contrast-enhanced magnetic resonance angiography that demonstrates a focal juxtaductal coarctation and prominent internal mammary and …

The value of high-resolution contrast-enhanced three-dimensional magnetic resonance angiography in the evaluation of hepatic arterial anatomy

目的 与DSA对照,评估高分辨对比增强三维MR血管成像(high-resolution 3D MRA)显示肝动脉解剖的价值.方法 回顾性分析26例肝肿瘤(24例为原发性肝癌,2例为转移性肝癌)患者腹部高分辨对比增强3D MRA和DSA检查的资料.对高分辨对比增强3D MRA和DSA的各段肝动脉显影质量行4级评分(1级记为1分,2级为2分,3级为3分,4级为4分),并对两者显影质量行weighted Kappa分析;分析评估肝动脉解剖或变异,以及病理情况,与DSA进行比较.结果 26例患者高分辨对比增强3D MRA和DSA对肝总动脉(显影评分平均为3.96、3.96)、胃十二指肠动脉(评分为3.85、3.88)的显示有很好的一致性(Kappa值分别为0.99、0.85),对肝右动脉(评分为3.92、3.96)、肝左动脉(评分为3.77、3.92)、胃左动脉(评分为3.73、3.85)、肝右前(评分为3.35、3.70)和右后动脉(评分为3.31、3.73)及第Ⅳ段动脉(评分为2.92、3.46)有较好的一致性(Kappa值分别为0.65、0.43、0.43、0.53、0.46、0.51),而对肝第Ⅱ(评分为2.15、3.35)、Ⅲ段动脉(评分为2.19、3.35)一致性差(Kappa值分别为0.18、0.21).以DSA为标准,高分辨对比增强3D MRA准确显示18例正常解剖和7例变异[显示的准确度为96.1%(25/26)],1例胃十二指肠动脉闭塞.结论 高分辨对比增强3D MRA是一项能准确评估肝动脉的检查技术,可以达到肝段动脉的显示水平。