Dynamic Contrast-enhanced MR Angiography Research Articles

Overview of multimodal MRI of intracranial Dural arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) include a wide range of pathological conditions that are associated with intracranial vessel abnormalities. While some types of DAVFs present with typical neuroimaging characteristics, others share overlapping pathological and neuroimaging features that can hinder accurate differentiation. Hence, misclassification of the various types of DAVFs is common. Thorough knowledge of DAVF imaging findings is essential to avoid such misinterpretations. Traditional digital subtraction angiography (DSA) is considered the gold standard for diagnosing and evaluating DAVFs. However, angiography cannot detect changes in a patient's brain structure. Conventional magnetic resonance imaging (MRI) sequences, including MR angiography (MRA), allow the evaluation of DAVFs without ionizing radiation or invasiveness. Advanced MRI techniques, such as susceptibility-weighted imaging (SWI) and dynamic contrast-enhanced MRA, provide added value to real-time physio-pathological data regarding the hemodynamics of DAVFs. Beyond these techniques, new insights using high-resolution vascular wall MRI are incorporated for the noninvasive evaluation of DAVFs. This article reviews the pathophysiology of DAVFs, focusing on the specifics of MRI findings that facilitate their classification. The role of conventional and advanced MRI sequences for DAVFs was assessed using insights derived from the data provided by structured reports of multimodal MRIs to evaluate DAVFs.

Red Blood Cell Membrane-Coated Ultrasmall NaGdF4 Nanoprobes for High-Resolution 3D Magnetic Resonance Angiography.

Enhanced angiography based on magnetic resonance imaging (MRI) has emerged as a noninvasive, robust, and high-resolution imaging technique for the clinical evaluation of vascular diseases. However, the effects of clinical Gd-chelating contrast agents are unsatisfactory for MRI contrast enhancement owing to their short blood half-life caused by rapid vascular extravasation, especially in microvessels. To address these issues, nanoprobes based on red blood cell membrane-coated ultrasmall NaGdF4 nanoparticles that exhibit much higher longitudinal molar relaxivity (r1) than the clinically used contrast agent gadolinium diethylenetriaminepentaacetic acid have been developed. Furthermore, the appropriate hydrodynamic diameter and stealth nature aid the nanoprobes to reside longer within the blood vessels without extravasation, thereby increasing the contrast between the blood vessels and surrounding tissues. Through probe-enhanced three-dimensional (3D) dynamic contrast-enhanced MR angiography, the main arteries and veins of the mouse were readily discernible, and even tiny vessels with sub-millimeter diameters could be clearly depicted. With this level of outstanding MR angiography performance, the embolization and recanalization processes of the carotid artery can be serially monitored with high imaging resolution using only a single injection. Additionally, the results of clearance studies and the toxicity tests further highlight the safety features of the nanoprobe. To summarize, the nanoprobes used in this study exhibit less extravascular leakage and a longer blood half-life, thus successfully overcoming the defects of the conventional low-molecular-weight Gd-based contrast agents and demonstrating their potential usefulness in enhanced MR angiography.

Bow Hunter’s syndrome: an unusual case of bilateral dynamic occlusion of vertebral arteries

A 54-year-old man came to our attention complaining of occasional tinnitus and blurred vision for 2 years, particularly when driving, the symptoms were linked to rightward head rotation. Neurological examination...

A Novel Collateral Imaging Method Derived from Time-Resolved Dynamic Contrast-Enhanced MR Angiography in Acute Ischemic Stroke: A Pilot Study.

Assessment of the collateral status has been emphasized for appropriate treatment decisions in patients with acute ischemic stroke. The purpose of this study was to introduce a multiphase MRA collateral imaging method (collateral map) derived from time-resolved dynamic contrast-enhanced MRA and to verify the value of the multiphase MRA collateral map in acute ischemic stroke by comparing it with the multiphase collateral imaging method (MRP collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion. From a prospectively maintained registry of acute ischemic stroke, MR imaging data of patients with acute ischemic stroke caused by steno-occlusive lesions of the unilateral ICA and/or the M1 segment of the MCA were analyzed. We generated collateral maps using dynamic signals from dynamic contrast-enhanced MRA and DSC-MRP using a Matlab-based in-house program and graded the collateral scores of the multiphase MRA collateral map and the MRP collateral map independently. Interobserver reliabilities and intermethod agreement between both collateral maps for collateral grading were tested. Seventy-one paired multiphase MRA and MRP collateral maps from 67 patients were analyzed. The interobserver reliabilities for collateral grading using multiphase MRA or MRP collateral maps were excellent (weighted κ = 0.964 and 0.956, respectively). The agreement between both collateral maps was also excellent (weighted κ = 0.884; 95% confidence interval, 0.819-0.949). We demonstrated that the dynamic signals of dynamic contrast-enhanced MRA could be used to generate multiphase collateral images and showed the possibility of the multiphase MRA collateral map as a useful collateral imaging method in acute ischemic stroke.

Evaluation of fistulas locations of spinal dural arteriovenous fistula by three-dimensional dynamic contrast-enhanced MR angiography

Evaluation of fistulas locations of spinal dural arteriovenous fistula by three-dimensional dynamic contrast-enhanced MR angiography

High-resolution dynamic CE-MRA of the thorax enabled by iterative TWIST reconstruction.

To evaluate the clinical benefit of using a new iterative reconstruction technique fully integrated on a standard clinical scanner and reconstruction system using a TWIST acquisition for high-resolution dynamic three-dimensional contrast-enhanced MR angiography (CE-MRA). Low-dose, high-resolution TWIST datasets of 11 patients were reconstructed using both standard GRAPPA-based reconstruction for reference and iterative reconstruction, which reduces the temporal footprint of reconstructed images. Image quality of both techniques was assessed by two experienced readers, as well as quantitatively evaluated using a time-signal curve analysis. Image quality scores consistently and significantly improved by using iterative reconstruction compared with the standard approach. Most notably, the delineation of small to mid-size vasculature improved from a mean Likert score between "nondiagnostic" and "poor" for standard to between "good" and "excellent" for iterative reconstruction. The full width at half maximum of the contrast agent bolus computed from the time-signal curve was also reduced by iterative reconstruction, allowing for more precise bolus timing. Iterative reconstruction can substantially improve high-resolution dynamic CE-MRA image quality, most notably in small to mid-size vasculature. Dynamic CE-MRA with iterative reconstruction could become an alternative to conventional static 3D CE-MRA, thus simplifying the clinical workflow. Magn Reson Med 77:833-840, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Combined dynamic contrast-enhanced liver MRI and MRA using interleaved variable density sampling

To develop and evaluate a method for volumetric contrast-enhanced MRI of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography (MRA) using a single injection of contrast agent. An interleaved variable density (IVD) undersampling pattern was implemented in combination with a real-time-triggered, time-resolved, dual-echo 3D spoiled gradient echo sequence. Parallel imaging autocalibration lines were acquired only once during the first time frame. Imaging was performed in 10 subjects with focal nodular hyperplasia (FNH) and compared with their clinical MRI. The angiographic phase of the proposed method was compared with a dedicated MR angiogram acquired during a second injection of contrast. A total of 21 FNH, three cavernous hemangiomas, and 109 arterial segments were visualized in 10 subjects. The temporally resolved images depicted the characteristic arterial enhancement pattern of the lesions with a 4-s update rate. Images were graded as having significantly higher quality compared with the clinical MRI. Angiograms produced from the IVD method provided noninferior diagnostic assessment compared with the dedicated MR angiogram. Using an undersampled IVD imaging method, we have demonstrated the feasibility of obtaining high spatial and temporal resolution dynamic contrast-enhanced imaging and simultaneous MRA of the liver.

Comparison of Dynamic Contrast-Enhanced 3T MR and 64-Row Multidetector CT Angiography for the Localization of Spinal Dural Arteriovenous Fistulas

For the localization of spinal dural arteriovenous fistulas, it is not determined whether dynamic contrast-enhanced MRA is more reliable than multidetector CTA. The aim of this study was to compare the agreement between intra-arterial DSA, dynamic contrast-enhanced MRA at 3T, and 64-row multidetector CTA for the localization of spinal dural arteriovenous fistulas. We enrolled 12 consecutive patients (11 men, 1 woman; age range, 46-83 years; mean, 65 years) who underwent preoperative dynamic contrast-enhanced MRA at 3T and 64-row multidetector CTA. The spinal dural arteriovenous fistula location was confirmed by intra-arterial DSA as the reference standard. Two reviewers independently evaluated the level of the artery feeding the spinal dural arteriovenous fistula on the basis of continuity between the feeder and abnormal spinal vessels on 3T dynamic contrast-enhanced MRA and 64-row multidetector CTA images. Interobserver and intermodality agreement was determined by calculation of the κ coefficient. On DSA, the vessel feeding the spinal dural arteriovenous fistula was the intercostal artery (7 cases), the lumbar artery (3 cases), and the internal iliac artery or the ascending pharyngeal artery (1 case each). For the fistula level, interobserver agreement was excellent for 3T dynamic contrast-enhanced MRA (κ = 0.97; 95% CI, 0.92-1.00) and very good for 64-row multidetector CTA (κ = 0.84; 95% CI, 0.72-0.96). Intermodality agreement with DSA was good for 3T dynamic contrast-enhanced MRA (κ = 0.78; 95% CI, 0.49-1.00) and moderate for 64-row multidetector CTA (κ = 0.41; 95% CI, 0.020-0.84). For the localization of spinal dural arteriovenous fistulas, 3T dynamic contrast-enhanced MRA may be more reliable than 64-row multidetector CTA.

High spatial and temporal resolution dynamic contrast-enhanced magnetic resonance angiography using compressed sensing with magnitude image subtraction

We propose a compressed-sensing (CS) technique based on magnitude image subtraction for high spatial and temporal resolution dynamic contrast-enhanced MR angiography (CE-MRA). Our technique integrates the magnitude difference image into the CS reconstruction to promote subtraction sparsity. Fully sampled Cartesian 3D CE-MRA datasets from 6 volunteers were retrospectively under-sampled and three reconstruction strategies were evaluated: k-space subtraction CS, independent CS, and magnitude subtraction CS. The techniques were compared in image quality (vessel delineation, image artifacts, and noise) and image reconstruction error. Our CS technique was further tested on seven volunteers using a prospectively under-sampled CE-MRA sequence. Compared with k-space subtraction and independent CS, our magnitude subtraction CS provides significantly better vessel delineation and less noise at 4× acceleration, and significantly less reconstruction error at 4× and 8× (P < 0.05 for all). On a 1-4 point image quality scale in vessel delineation, our technique scored 3.8 ± 0.4 at 4×, 2.8 ± 0.4 at 8×, and 2.3 ± 0.6 at 12× acceleration. Using our CS sequence at 12× acceleration, we were able to acquire dynamic CE-MRA with higher spatial and temporal resolution than current clinical TWIST protocol while maintaining comparable image quality (2.8 ± 0.5 vs. 3.0 ± 0.4, P = NS). Our technique is promising for dynamic CE-MRA.

MR angiography of carotid artery aneurysms in a porcine model at 3 tesla: Comparison of two different macrocyclic gadolinium chelates and of dynamic and conventional techniques

To evaluate the differences in image quality of two macrocyclic gadolinium-based contrast agents, gadobutrol and gadoterate meglumine, using time-resolved, contrast-enhanced MR angiography (CE-MRA) in a porcine carotid artery aneurysm model and to compare image quality between dynamic and conventional, single acquisition CE-MRA. Bilateral carotid aneurysms were created surgically in this Institutional Animal Care and Use Committee approved study. Dynamic CE-MRA studies optimized for high temporal resolution were performed at 3 Tesla. Scans using equivalently dosed (on a per mmol basis) gadobutrol and gadoterate meglumine were compared qualitatively and quantitatively in terms of contrast-to-noise ratio (CNR). Higher spatial resolution dynamic and conventional CE-MRA were also compared. N = 16 aneurysms were assessed. Qualitative evaluation of dynamic CE-MRA scans demonstrated a preference for gadobutrol over gadoterate meglumine. Significantly higher aneurysm CNR was found with gadobutrol (133 ± 44) versus gadoterate meglumine, the latter at both equivalent and double injection rates (94 ± 35 and 102 ± 38). In a blinded assessment, conventional CE-MRA was preferred qualitatively when compared with dynamic CE-MRA. However, dynamic CE-MRA was generally capable of providing diagnostic image quality. Gadobutrol is preferred to gadoterate meglumine for high temporal resolution dynamic CE-MRA, a fact with important clinical implications for low dose CE-MRA protocols in patients at risk for nephrogenic systemic fibrosis. Conventional high resolution CE-MRA provides superior image quality when compared with dynamic CE-MRA.

Clinical application and diagnostic value of non-invasive spinal angiography in spinal vascular malformations

Objective To explore the value of CT spinal angiography with 256 MSCT and fast dynamic contrast-enhanced 3D MR angiography (CE-MRA) at 3.0 T in the diagnosis of spinal vascular malformations by comparing with results of DSA and operation.Methods Seventeen patients suspected of spinal vascular diseases by initial MR and clinical manifestations all underwent CT spinal angiography.Of them,10 patients underwent MRA,15 patients underwent DSA within 3-5 days,and 8 patients finally underwent surgical treatment.Results CTA examination clearly showed the abnormal vascular lesions in 16 of 17 cases,including 7 cases with the diagnosis of spinal dural arteriovenous fistula,7 cases of perimedullary arteriovenous fistula,and 2 cases of spinal arteriovenous malformations. The results were consistent with the diagnosis of DSA or surgery.One case was poorly diagnosed.The feeding vessels were correctly determined in 12 cases,and the level of fistulas were correctly displayed in 12 cases.The level of fistulas and feeding vessels were accurately showed in 7 of 10 cases with MRA,while the other 3 cases exhibited normal with DSA.Conclusions Spinal angiography with 256 MSCT and CE-MRA at 3.0 T can clearly show the extent of spinal vascular malformations,feeding arteries and fistula location.They are safe,noninvasive,convinient and can shorten the time of DSA diagnosis and treatment.They play an important role in diagnosis and treatment of spinal vascular malformations and postoperative follow-up. Key words: Spinal cord vascular diseases; Magnetic resonance imagiag; Tomography, X-ray computed; Angiography,digital subtraction

Posterior fossa dural arteriovenous fistulas: diagnosis and follow-up with time-resolved imaging of contrast kinetics (TRICKS) at 1.5T

Time-of-flight MR angiography (TOF MRA) is currently the most widely used non-invasive imaging tool to diagnose dural arteriovenous fistula (DAVF). It is, however, not as sensitive as invasive digital subtraction angiography (DSA) for detecting the arteriovenous shunting inherent in DAVF. Dynamic contrast-enhanced MR angiography allows separation of arterial and venous phases of contrast passage though the brain and can thus demonstrate early venous filling through the arteriovenous shunt. To compare the diagnostic value of TOF MRA and a commercially available dynamic contrast-enhanced MR angiography sequence (TRICKS) at 1.5T in detecting posterior fossa DAVF. We retrospectively collected image data for 19 patients who underwent TOF MRA, TRICKS, and DSA either for primary diagnosis or for follow-up of posterior fossa DAVF and assessed the performance of TOF MRA and TRICKS in demonstrating the arteriovenous shunt, with DSA as the reference standard. TRICKS detected early arterial filling at 94.4% sensitivity and 83.3% specificity. TOF MRA detected high flow-related signal within venous structures at 64.7% sensitivity and 80% specificity. The commercially available dynamic MR angiography sequence TRICKS with fully automatic vendor postprocessing at 1.5T is more sensitive than TOF MRA in detecting the arteriovenous shunt in posterior fossa DAVF.

Interleaved variable density sampling with a constrained parallel imaging reconstruction for dynamic contrast-enhanced MR angiography

For MR applications such as contrast-enhanced MR angiography, it is desirable to achieve simultaneously high spatial and temporal resolution. The current clinical standard uses view-sharing methods combined with parallel imaging; however, this approach still provides limited spatial and temporal resolution. To improve on the clinical standard, we present an interleaved variable density (IVD) sampling method that pseudorandomly undersamples each individual frame of a 3D Cartesian ky-kz plane combined with parallel imaging acceleration. From this dataset, time-resolved images are reconstructed with a method that combines parallel imaging with a multiplicative constraint. Total acceleration factors on the order of 20 are achieved for contrast-enhanced MR angiography of the lower extremities, and improvements in temporal fidelity of the depiction of the contrast bolus passage are demonstrated relative to the clinical standard.

Evaluation of renal vascular in living donors before transplantation using dynamic contrast enhanced MR angiography

Objective To explore whether dynamic contrast-enhanced MRA (DCE MRA) can provide an effective assessment of renal vascular in living donors before transplantation.Methods Thirty five healthy living renal donor candidates were scanned on MR system before transplantation.After injection of Gd-DTPA 1 ml in vein, a test-bolus scan was used to get the time delay of Gd-DTPA reaching renal artery.Then, a 3D T1-weighted fast low-angle shot sequence (3D FLASH) was performed in the coronal plane.The 3D FLASH scan would repeat four times with an inter-phase of 10 seconds.Thus, the imaging of the renal arterial, venous and collecting systems were got.Two radiologists observed renal arteries and veins on original imaging and MIP reconstructed imaging.The quality of MR angiography was evaluated on a fivepoint scale and the vascular anatomy or variations of the arterial and venous systems were recorded, using intraoperative findings as a standard of reference.Results The quality for all MRA was good or very good for the most of living renal donors.Among 70 renals, several variations of vascular were found, including 5 left accessory artery, 9 right accessory artery, 3 left proximal arterial branch and 6 right proximal arterial branch.Among 70 renal veins, 1 right accessory veins and 2 left varieocele were observed.One small accessory artery of right kidney was missed with DCE MRA, but identified by operation.Conclusion DCE MRA was noninvasive tool for evaluation of the renal vasculature and variations with high accuracy.It would be a good modality in preoperative evaluation of living renal donors. Key words: Kidney transplantation; Magnetic resonance angiography

3D undersampled golden‐radial phase encoding for DCE‐MRA using inherently regularized iterative SENSE

One of the current limitations of dynamic contrast-enhanced MR angiography is the requirement of both high spatial and high temporal resolution. Several undersampling techniques have been proposed to overcome this problem. However, in most of these methods the tradeoff between spatial and temporal resolution is constant for all the time frames and needs to be specified prior to data collection. This is not optimal for dynamic contrast-enhanced MR angiography where the dynamics of the process are difficult to predict and the image quality requirements are changing during the bolus passage. Here, we propose a new highly undersampled approach that allows the retrospective adaptation of the spatial and temporal resolution. The method combines a three-dimensional radial phase encoding trajectory with the golden angle profile order and non-Cartesian Sensitivity Encoding (SENSE) reconstruction. Different regularization images, obtained from the same acquired data, are used to stabilize the non-Cartesian SENSE reconstruction for the different phases of the bolus passage. The feasibility of the proposed method was demonstrated on a numerical phantom and in three-dimensional intracranial dynamic contrast-enhanced MR angiography of healthy volunteers. The acquired data were reconstructed retrospectively with temporal resolutions from 1.2 sec to 8.1 sec, providing a good depiction of small vessels, as well as distinction of different temporal phases.

Contrast Material for Abdominal Dynamic Contrast-Enhanced 3D MR Angiography With Parallel Imaging: Intraindividual Equimolar Comparison of a Macrocyclic 1.0 M Gadolinium Chelate and a Linear Ionic 0.5 M Gadolinium Chelate

The purpose of this study was to compare a macrocyclic 1.0 M contrast agent with a linear ionic 0.5 M contrast agent at equimolar dosage in regard to image quality and number of vessel segments visualized at abdominal dynamic contrast-enhanced 3D MR angiography. In an intraindividual comparative study, 15 patients (six women, nine men; mean age, 53 +/- 12.1 years; range, 25-72 years) underwent 32 1.5-T whole-body contrast-enhanced 3D MR angiographic examinations performed with parallel imaging technique. At random and in separate sessions, each patient was examined after IV injection of 0.1 mmol/kg body weight 1.0 M macrocyclic gadobutrol and 0.5 M linear ionic gadopentetate dimeglumine. Three-dimensional data sets were acquired in the arterial, portal venous, and venous phases with identical imaging protocols. Quantitative analysis included contrast measurements of vessels compared with adjacent background tissue (Student's t test). Qualitative analysis was performed independently by two radiologists with regard to visualization of arterial and venous vessel segments and overall image quality (Wilcoxon's test). Visualization of individual vessel segments was rated significantly better after administration of 1.0 M macrocyclic gadobutrol compared with 0.5 M linear ionic gadopentetate dimeglumine (p < 0.001). Overall image quality was superior with 1.0 M macrocyclic gadobutrol, but the difference was not significant. Vessel-to-background contrast after injection of 1.0 M macrocyclic gadobutrol was significantly higher (arterial phase, 0.90, p = 0.02; portal venous phase, 0.78, p = 0.0002; venous phase, 0.74, p = 0.0002) compared with 0.5 M linear ionic gadopentetate dimeglumine (arterial phase, 0.89; portal venous phase, 0.73; venous phase, 0.67). At abdominal contrast-enhanced 3D MR angiography, depiction of small abdominal vessels was significantly better and vessel-to-tissue contrast significantly higher with 1.0 M macrocyclic gadobutrol than with an equimolar dose of 0.5 M linear ionic gadopentetate dimeglumine.

Optimal k‐space sampling for dynamic contrast‐enhanced MRI with an application to MR renography

For time-resolved acquisitions with k-space undersampling, a simulation method was developed for selecting imaging parameters based on minimization of errors in signal intensity versus time and physiologic parameters derived from tracer kinetic analysis. Optimization was performed for time-resolved angiography with stochastic trajectories (TWIST) algorithm applied to contrast-enhanced MR renography. A realistic 4D phantom comprised of aorta and two kidneys, one healthy and one diseased, was created with ideal tissue time-enhancement pattern generated using a three-compartment model with fixed parameters, including glomerular filtration rate (GFR) and renal plasma flow (RPF). TWIST acquisitions with different combinations of sampled central and peripheral k-space portions were applied to this phantom. Acquisition performance was assessed by the difference between simulated signal intensity (SI) and calculated GFR and RPF and their ideal values. Sampling of the 20% of the center and 1/5 of the periphery of k-space in phase-encoding plane and data-sharing of the remaining 4/5 minimized the errors in SI (<5%), RPF, and GFR (both <10% for both healthy and diseased kidneys). High-quality dynamic human images were acquired with optimal TWIST parameters and 2.4 sec temporal resolution. The proposed method can be generalized to other dynamic contrast-enhanced MRI applications, e.g., MR angiography or cancer imaging.

The clinical application studies of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations

Background and purpose To explore the value of CT spinal angiography with 64-detector row spiral CT in diagnosing spinal vascular malformations. Methods Seventeen patients with initial MR and clinical findings suggestive of spinal vascular diseases underwent CT spinal angiography. Among these, 14 patients took DSA examination within 1 week after CT scan, 7 patients underwent surgical treatment, and 6 patients underwent vascular intervention embolotheraphy. CT protocol: TOSHIBA Aquilion 64 Slice CT scanner, 0.5 mm thickness, 0.5 s/r, 120 kV and 350 mA, positioned at the aortic arch level, and applied with “sure start” technique with CT threshold of 180 Hu. Contrast agent Iohexol (370 mg I/ml) was injected at 6 ml/s velocity with total volume of 80 ml. The post-processing procedures included MPR, CPR, MIP, VR, etc. Among the 17 patients, four patients underwent fast dynamic contrast-enhanced 3D MR angiography imaging. CT spinal angiography and three-dimensional contrast-enhanced MR angiography (3D CE-MRA) images were compared and evaluated with DSA and operation results based on disease type, lesion range, feeding arteries, fistulas, draining veins of vascular malformation by three experienced neuroradiologists independently, using double blind method. The data were analyzed using SPSS analytic software with χ 2-test. We compared the results with DSA and operation results. Results The statistical analysis of the diagnostic results by the three experienced neuroradiologists had no statistical difference ( P > 0.05). All of the 17 patients showed clearly the abnormality of spinal cord vessels and the range of lesions by CT spinal angiography. Among them, one patient was diagnosed as arteriovenous fistulas (AVF) by MRI and CT spinal angiography, which was verified by surgical operation. DSA of the same patient, however, did not visualize the lesion. One case was diagnosed as AVM complicated with AVF by DSA, but CT spinal angiography could only show AVM not AVF. The type differentiations of all the other 16 patients were consistent with DSA results. For 13 cases with positive CT spinal angiography results, DSA displayed 20 feeding vessels, among which 16 vessels were displayed correctly by CT spinal angiography, four could not be visualized, and two turned out to be false-positive. Fistulas were not displayed in six cases by CT spinal angiography. Draining veins were displayed clearly in all cases, which agreed with DSA results. Four cases who took CE-MRA obtained the same type diagnosis as that from CT spinal angiography. Feeding arteries were not displayed in CE-MRA of one case, but could be clearly visualized in other three cases, and the results agreed with CTA and DSA results. Fistulas could be seen in two cases. Draining veins and the disease range could be displayed distinctly by 3D CE-MRA. Conclusion CT spinal angiography is quite valuable for diagnosing vascular malformation of spinal cord. It can be a screening exam before DSA, and has a guiding effect on DSA, reducing the amount of time required for DSA.

Cavernous transformation of the portal vein: three-dimensional dynamic contrast-enhanced MR angiography

Cavernous transformation of the portal vein: three-dimensional dynamic contrast-enhanced MR angiography

Cavernous transformation of the portal vein: three-dimensional dynamic contrast-enhanced MR angiography

Cavernous transformation of the portal vein: three-dimensional dynamic contrast-enhanced MR angiography