MR evaluation of the portal vein in pediatric liver transplant candidates

Nine pediatric liver transplant candidates underwent preoperative MR evaluation of the portal vein and the inferior vena cava. Sonographic correlation was available in all patients and angiographic correlation was available in five. Pathologic correlation was obtained in seven cases either at liver transplantation or autopsy. MR demonstrated portal vein patency in three cases when it was not seen by angiography and confirmed portal vein patency in one patient when it was questionably identified on sonography. The portal vein was not seen on MR imaging in two cases when it was seen on sonography and angiography: in one case, it was small and to-and-fro flow was demonstrated angiographically; in the second case, the portal vein was occluded by tumor thrombus. Two vessels in two patients were misidentified by sonography and identified correctly by MR. These were an azygous continuation of the inferior vena cava and a large collateral vein in the portal region. Knowledge of the anatomy and documentation of vascular patency are essential in evaluation of patients before liver transplantation. In patients with complex anatomy or hemodynamics, it may be necessary to obtain this information from several imaging techniques (sonography, angiography, and MR).     

MR angiography and dynamic flow evaluation of the portal venous system

We studied the value of MR angiographic techniques in imaging the portal venous system. Projection angiograms were created by postprocessing a series of two-dimensional, flow-compensated gradient-echo images. Flow velocity was determined by a bolus-tracking method with radiofrequency tagging and multiple data readout periods. Each image was acquired during a breath-hold. MR angiography was applied to six normal subjects and four patients with abnormal hemodynamics in the portal venous system. Flow velocity determined by MR was correlated with the results of duplex sonography. The main portal vein and intrahepatic branches were shown in all cases. Portosystemic collaterals were identified in all patients with portal hypertension. In normal subjects, peak flow velocities (17.9 +/- 2.8 cm/sec) on MR correlated well with values determined by duplex sonography (17.5 +/- 2.2 cm/sec) (r = .846, p less than .04). Reversed portal blood flow was shown in two patients. One patient with portal vein thrombosis had no evidence of flow by MR angiography. Our results indicate that MR angiography can provide a three-dimensional display of normal and abnormal vascular anatomy as well as functional information in the portal venous system.     

The correlation between MR and angiography in portal hypertension

Forty-two MR examinations and hepatic panangiograms in 38 patients with portal hypertension were correlated with MR images to determine the ability of MR to detect portal vein hemodynamics. These studies were prospectively analyzed for degree of portal perfusion and direction of flow, portal vein thrombosis, and presence and type of shunt surgery. Thirty-three MR examinations were determined to have grade I (good) or II (fair) portal blood flow. Twenty-nine of these were grade I or II by angiography; the other four were grade IV. Of the eight cases documented as grade IV (hepatofugal portal blood flow) by angiography, none were considered grade IV by MR, suggesting that MR was unable to detect retrograde flow. The other case was not graded because of cavernous transformation of the portal vein. MR correlated well with angiography for the detection or absence of portal vein thrombus, agreeing with angiography in 41 of 42 cases. Two angiographically proven cases of portal vein thrombosis were correctly identified on MR. MR correctly identified the absence of portal vein clot in 39 of 40 angiographically negative cases. MR and angiography also agreed in 41 of 42 cases that a shunt was either present/absent or patent/occluded. The single error was due to inadequate MR scanning in the region of interest. The results show that MR cannot be used to grade blood flow in the portal vein. However, MR accurately detects portal vein thrombosis and the patency of surgical shunts.     

Angiography of liver transplantation patients

Over 45 months, 119 angiographic examinations were performed in 95 patients prior to liver transplantation, and 53 examinations in 44 patients after transplantation. Transplantation feasibility was influenced by patency of the portal vein and inferior vena cava. Selective arterial portography, wedged hepatic venography, and transhepatic portography were used to assess the portal vein if sonography or computed tomography was inconclusive. Major indications for angiography after transplantation included early liver failure, sepsis, unexplained elevation of liver enzyme levels, and delayed bile leakage, all of which may be due to hepatic artery thrombosis. Other indications included gastrointestinal tract bleeding, hemobilia, and evaluation of portal vein patency in patients with chronic rejection who were being considered for retransplantation. Normal radiographic features of hepatic artery and portal vein reconstruction are demonstrated. Complications diagnosed using results of angiography included hepatic artery or portal vein stenoses and thromboses and pancreaticoduodenal aneurysms. Intrahepatic arterial narrowing, attenuation, slow flow, and poor filling were seen in five patients with rejection.     

Vascular complications after living related liver transplantation: evaluation with gadolinium-enhanced three-dimensional MR angiography

OBJECTIVE: The purpose of this study was to evaluate the efficacy of gadolinium-enhanced three-dimensional (3D) MR angiography for detection of vascular complications in patients who have undergone living related liver transplantation. MATERIALS AND METHODS: Seventy-six patients who underwent living related liver transplantation were evaluated with gadolinium-enhanced 3D MR angiography. All MR angiograms were assessed for patency of the hepatic artery and the portal vein using a four-point scale (grades I-IV). The results were correlated with conventional angiography (n = 23) and clinical follow-up with Doppler sonography (n = 53) for more than 6 months. RESULTS: Seventy-three of 76 MR angiography procedures were technically adequate. When grades III (focal narrowing [> 50%] at the anastomotic site) and IV (abrupt cutoff at the anastomotic site with nonvisualization of the right [or left] hepatic artery distal to the anastomosis) were regarded as the diagnostic criteria for hepatic artery stenosis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MR angiography were 100%, 74%, 29%, 100%, and 77%, respectively. In the portal vein, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MR angiography were 100%, 84%, 35%, 100%, and 85%, respectively, when grades III (narrowing [> 50%] without poststenotic dilatation) and IV (narrowing [> 50%] with poststenotic dilatation) were defined as criteria for portal vein stenosis. CONCLUSION: MR angiography was sensitive but not specific in the detection of significant vascular stenosis after living related liver transplantation. However, normal MR angiography findings reliably exclude the possibility of significant stenosis.     

Magnetic resonance portal venography: use of fast-acquisition true FISP imaging in the detection of portal vein thrombosis

AIM: To determine the accuracy of true fast imaging with steady-state precession (true FISP) in the diagnosis of portal vein thrombosis in patients with cirrhosis and compare it to contrast-enhanced three-dimensional (3D) magnetic resonance (MR) angiography, the reference standard. MATERIALS AND METHODS: Twenty-four consecutive patients with suspected portal venous thrombosis underwent contrast-enhanced 3D MR angiography and true FISP imaging of the portal vein. All patients had undergone at least one other imaging study, either computed tomography, (CT) or ultrasound. Both sets of MR images were evaluated for patency of the portal venous system and for image quality. RESULTS: Portal vein thrombosis was diagnosed in six of the 24 patients. Four patients with portal vein thrombosis were accurately diagnosed on the true FISP sequence. This sequence also accurately diagnosed the patency of the portal vein in 17 patients. However, the results were inconclusive in three patients. The image quality of the true FISP sequence of the three inconclusive patients was graded as either poor or fair. Of these three patients, contrast-enhanced 3D MR angiography confirmed portal vein thrombosis in two patients and portal vein stenosis in one patient. True FISP imaging had a sensitivity of 67% and a specificity of 100% for the diagnosis of portal vein thrombosis. CONCLUSION: The results of the present study show that the true FISP sequence is useful in diagnosing portal vein thrombosis. It could be employed as an adjunct to contrast-enhanced MR angiography in the severely debilitated patient where respiratory motion may degrade the images or in patients where the use of intravenous contrast medium is not possible due to poor venous access.     

Liver transplant recipients: portable duplex US with correlative angiography

Twenty patients, aged 4 months to 58 years, were evaluated for liver transplantation by duplex sonography, and 15 transplantations were completed; 42 postoperative examinations were performed. Sonographic findings were correlated with seven preoperative and five postoperative angiographic evaluations. Preoperative duplex US findings included tumors, portal vein occlusion, varices, biliary obstruction, and variant vascular anatomy. Postoperative findings included hepatic artery occlusion, portal vein occlusions (one with cavernous transformation), portal vein stenosis, biliary obstruction, intrahepatic and extrahepatic fluid collections, and air in the portal vein due to ischemic bowel. Use of angiography allowed confirmation of the vascular abnormalities and demonstrated evidence of rejection in patients with normal Doppler waveforms. Duplex sonography is a valuable portable technique for evaluating these patients and can be used in triage of patients requiring angiography.     

Hemodynamic changes in portal circulation after portosystemic shunts: use of duplex sonography in 43 patients

Forty-five patients with 46 surgical portosystemic shunts were examined by duplex Doppler sonography, and the results were compared with those of esophageal endoscopy, angiography, surgery, and clinical follow-up. Thirty-eight shunts were patent, and in 33 of these, the shunt was directly visualized and flow was observed with Doppler sonography. Eight shunts were obstructed. After a successful portosystemic shunt procedure, flow in the shunted splanchnic vein was directed toward the shunt and the systemic vein. We studied the intrahepatic portal venous circulation in all of the patients; we found that in the presence of patent portosystemic shunt, portal flow is hepatofugal. This reversal of blood flow occurred in all but four patients. In the end-to-side portacaval shunt, where the portal vein is ligated, blood in intrahepatic portal branches presumably reaches the shunt through perihepatic collaterals. In the presence of a thrombosed shunt, intrahepatic portal venous flow was hepatopetal. To our knowledge, this is the first noninvasive in vivo study of intrahepatic portal circulation after portosystemic shunt surgery. The duplex Doppler evaluation of portosystemic shunts appears to be reliable and should be the method of choice for shunt patency assessment in patients with recurrent signs of portal hypertension. In addition to demonstrating flow at the site of the anastomosis, the Doppler study may yield an easy and reliable sign of shunt patency: reversed flow (hepatofugal flow) in the intrahepatic portal veins probably signals a patent shunt, even if the site of the anastomosis cannot be visualized directly by sonography.     

Hemodynamic significance of the paraumbilical vein in portal hypertension: assessment with duplex US

Hemodynamic evaluation of portal and umbilical venous flow with duplex ultrasound (US) was performed in 11 patients with cirrhosis of the liver and a large umbilical vein. Two of these patients had hepatofugal flow in the umbilical vein exceeding hepatopetal flow in the portal vein. These two patients had no evidence of esophageal varices and bleeding. The remaining nine patients had esophageal varices. In these patients, the hepatopetal flow in the portal vein exceeded the hepatofugal flow through the umbilical vein. The authors conclude that duplex US may help identify the massive hepatofugal flow through a large umbilical vein that may reduce the likelihood of esophageal varices and variceal bleeding.     

Three-dimensional gadolinium-enhanced MR angiography of vascular complications after liver transplantation

OBJECTIVE: The goal of this study was to evaluate three-dimensional gadolinium-enhanced MR angiography as a tool for examination of liver transplant patients with potential vascular complications. MATERIALS AND METHODS: Thirty-eight consecutive three-dimensional gadolinium-enhanced MR angiograms were obtained in 34 patients. Results were retrospectively reviewed and correlated with conventional angiography in 20 of the 38 cases and sonography in 37 of the 38 cases. MR angiograms were evaluated for technical adequacy, vascular patency, and parenchymal abnormalities, and results were compared with angiography and sonography. Conventional angiography and surgery were used as gold standards when available. RESULTS: Thirty-four (90%) of 38 MR angiograms were technically adequate. Vascular abnormalities were identified in 20 patients, and 19 of these patients subsequently underwent angiography, surgery, or both. There were seven cases of hepatic artery thrombosis; all were detected with MR angiography with no false-positive or false-negative interpretations. Seven patients had moderate to severe hepatic artery stenosis (>50% narrowing as determined by conventional angiography). MR angiography revealed this stenosis in six of the seven patients, with one false-negative and three false-positive interpretations. Portal vein thrombosis was detected in three patients, and portal vein stenosis was detected in two patients. CONCLUSION: Three-dimensional gadolinium-enhanced MR angiography is useful in the examination of liver transplant patients and offers a noninvasive adjunct in patients with difficult or indeterminate sonographic examinations.     

Diagnosis of portal vein thrombosis: value of color Doppler imaging.

This study was undertaken to determine the accuracy of color Doppler imaging in the diagnosis of portal vein thrombosis. Two hundred fifteen patients were studied with color Doppler imaging to determine patency of the main portal vein. Sonographic findings were confirmed in 75 patients, aged 19 to 66 years. Correlation with angiography was obtained in 13 patients, and surgical correlation was obtained in the remaining 62. Nine patients had portal vein thrombosis on the basis of these gold standards. Sonograms were classified as showing either patency or thrombosis, depending on the ability to show color flow within the main portal vein. Agreement between sonography and angiography or surgery was found in 69 patients (61 patent, eight thrombosed). One patient with a patent portal vein at sonography was found to have a thrombosed vessel at surgery, whereas five patients without portal venous flow at sonography had patent vessels at angiography (one patient) or surgery (four patients). Overall sensitivity and specificity for detection of portal vein thrombosis were 89% and 92%, with an accuracy of 92%, a false-negative rate of 0.11, a negative predictive value of 0.98, and a positive predictive value of 0.62. We postulate that the majority of errors in our study occurred in vessels that, although patent, had only sluggish flow, which could not be resolved because of technical limitations. We conclude that color Doppler imaging is a valuable screening procedure for the assessment of portal vein patency. If the sonogram shows a patent portal vein, no further studies are required. However, a lack of demonstrable flow does not always indicate thrombosis, and other imaging studies should be performed for confirmation.     

Portal hypertension evaluated by MR imaging

Thirteen patients with portal hypertension were examined by magnetic resonance (MR) imaging, using spin-echo sequences, and by visceral angiography. Data from this group were compared with the MR images and angiograms of 20 patients without portal hypertension. MR imaging demonstrated two of three cases of portal vein occlusion and four of five cases of occlusion of the retropancreatic portion of the superior mesenteric vein. Two thirds of the patients with portal hypertension and patent portal veins had marked MR signal within the main portal vein on MR images. Little or no signal was present in the portal veins of the 20 patients without portal hypertension. Our experience indicates that marked intraportal MR signal can be seen in patients with portal hypertension with or without venous occlusion. In some cases the size and distribution of venous collaterals allow one to distinguish between venous occlusion and other causes of portal hypertension. MR images confirmed the patency of distal splenorenal shunts in two patients studied.     

Hepatofugal flow in the portal venous system: pathophysiology, imaging findings, and diagnostic pitfalls.

Hepatofugal flow (ie, flow directed away from the liver) is abnormal in any segment of the portal venous system and is more common than previously believed. Hepatofugal flow can be demonstrated at angiography, Doppler ultrasonography (US), magnetic resonance imaging, and computed tomography (CT). The current understanding of hepatofugal flow recognizes the role of the hepatic artery and the complementary phenomena of arterioportal and portosystemic venovenous shunting. Detection of hepatofugal flow is clinically important for diagnosis of portal hypertension, for determination of portosystemic shunt patency and overall prognosis in patients with cirrhosis, as a potential pitfall at invasive arteriography performed to evaluate the patency of the portal vein, and as a contraindication to specialized imaging procedures (ie, transarterial hepatic chemoembolization and CT during arterial portography). Hepatofugal flow is generally diagnosed at Doppler US without much difficulty, but radiologists should beware of pitfalls that can impede correct determination of flow direction in the portal venous system.     

Detection of thrombosis in the portal venous system: comparison of contrast-enhanced MR angiography with intraarterial digital subtraction angiography

PURPOSE: To determine whether intraarterial digital subtraction angiography (DSA) can be replaced by contrast material-enhanced magnetic resonance (MR) angiography in the assessment of patency or thrombosis of the portal venous system in patients with portal hypertension. MATERIALS AND METHODS: Thirty-six patients with portal hypertension underwent contrast-enhanced MR angiography and intraarterial DSA for assessment of the portal venous system. The images were evaluated for vessel patency or thrombosis of the portal, splenic, or superior mesenteric vein. RESULTS: Of the 101 vessels evaluated, 42 were thrombosed. Overall sensitivity, specificity, and accuracy for the detection of thrombosis were 100%, 98%, and 99%, respectively, for MR angiography and 91%, 100%, and 96%, respectively, for DSA; differences between the imaging methods were not statistically significant. Only in four patients with six vessels (6%) were there discordant findings between MR angiography and DSA. CONCLUSION: Noninvasive contrast-enhanced MR angiography has the potential to replace intraarterial DSA as the standard method to assess the whole portal venous system.     

Budd-Chiari syndrome: the results of duplex and color Doppler imaging

This study was designed to evaluate duplex and color-flow Doppler imaging as potential noninvasive methods of diagnosing patients with Budd-Chiari syndrome and following them after surgery. Five patients with confirmed hepatic venoocclusive disease were imaged. All five underwent duplex Doppler examinations; three were also evaluated with color-flow Doppler. The hepatic vasculature was examined in all five patients; decompressive mesoatrial shunts were present and were evaluated in four of the five patients. Color-flow Doppler precisely defined intrahepatic, portal, and inferior vena caval circulatory dynamics. Correlation with angiography was excellent. In the two patients in whom hepatic vasculature was evaluated with duplex Doppler alone, the results were less impressive. Intrahepatic flow abnormalities were identified, but the sites of occlusion were not determined convincingly. Signals transmitted from the heart and the inability to visualize the hepatic veins made duplex Doppler evaluation problematic. Duplex Doppler was able to define patency and the direction of flow in the portal vein and inferior vena cava. Our results suggest that color-flow Doppler is an excellent technique for the initial evaluation of patients suspected of having Budd-Chiari syndrome. In the evaluation of decompressive mesoatrial shunts, color-flow Doppler produced dramatic images. However, both duplex and color-flow Doppler were highly accurate in determining the patency of decompressive shunts. Either duplex or color-flow Doppler may be used as the primary imaging procedure to determine shunt patency.     

Clinical use of Levovist, an ultrasound contrast agent, in the imaging of liver transplantation: assessment of the pre- and post-transplant patient

Colour Doppler US is well established for imaging of hepatic vessels in the assessment of pre- and post-liver transplant patients. Unfortunately, a full colour Doppler US examination of the portal or hepatic venous and hepatic arterial systems is frequently precluded by technical factors. Ultrasound contrast agents are useful in enhancing vascular Doppler signal and play an important role in liver transplantation assessment. A series of patients with vascular problems illustrates the role of US contrast in the pre-transplant candidate, where portal vein patency and direction of flow is assessed, presence of portal vein thrombus is confirmed and cavernous transformation demonstrated. Occlusion of hepatic veins in Budd-Chiari syndrome is confidently confirmed. Following liver transplantation, US contrast allows a comprehensive assessment of hepatic artery thrombosis, hepatic artery stenosis and pseudoaneurysm formation. The need for further imaging is reduced or confidently deferred in many instances. Ultrasound contrast agents play an important role in the liver transplant candidate. Received: 15 April 1999; Revised: 21 June 1999; Accepted: 22 June 1999     

Preoperative evaluation of the entire hepatic vasculature in living liver donors with use of contrast-enhanced MR angiography and true fast imaging with steady-state precession

PURPOSE: To preoperatively assess the entire hepatic vasculature in living related liver donors with use of a combination of contrast material-enhanced magnetic resonance (MR) angiography and true fast imaging with steady-state precession (FISP). MATERIALS AND METHODS: Twenty-five living potential liver donors were examined preoperatively on a 1.5T Siemens Sonata system. Twenty-four underwent surgery and two had catheter angiography performed to delineate complex anatomy. Contiguous 5-mm-thick, sub-second true FISP images of the liver were initially obtained during breath-holding in axial and coronal planes (repetition time [TR]/echo time [TE], 3.2/1.6; flip angle, 70 degrees ). MR angiography was performed with use of a three-dimensional (3D) gradient-echo fast low-angle shot (FLASH) pulse sequence (TR/TE, 3.0/1.2; flip angle, 25 degrees ), with 40 mL of Gadolinium DTPA injected at a rate of 2 mL/sec. One precontrast and two postcontrast coronal 3D volumes were acquired, each in a 20-second breath-hold, and two subtracted 3D sets were calculated. Arterial anatomy was assessed with use of maximum-intensity projection, volume rendering, and multiplanar reformatting algorithms. Hepatic and portal venous anatomy was evaluated with use of the true FISP images and the venous phase of the MR angiogram. Visualization of hepatic arterial branches was noted. Visualization of portal vein branches was scored on a scale of 0-5. The presence of anatomic variants was noted. Vascular anatomy was confirmed at the time of surgery and at catheter angiography. RESULTS: Segmental branch vessels were visualized on MR angiography in the majority of cases. The segment four branch was identified in 96% patients. Variant arterial anatomy was seen in 50% of patients. MR angiography detected 10 of 11 arterial variants found at surgery and angiography. Visualization of portal vein branches was generally higher with true FISP compared to MR angiography. Twenty-four percent of patients had variant portal venous anatomy. Caudal hepatic veins were identified in 60% of patients, of which eight were significant (>5 mm). Hepatic and portal venous anatomy was accurately predicted by true FISP and MR angiography in all patients who went on to undergo surgery. CONCLUSION: Preoperative imaging with use of a combination of contrast-enhanced MR angiography and true FISP provides a comprehensive assessment of the entire hepatic vasculature in living liver donors.     

Doppler sonography: a noninvasive method for evaluation of hepatic venocclusive disease

Hepatic venocclusive disease is a serious complication associated with chemotherapy and radiation used in bone marrow transplantation patients. In the past, liver biopsy has been the only reliable means of diagnosing venocclusive disease. Biopsy in such patients may be dangerous or impossible because of severe coagulopathies. The purpose of our study was to evaluate duplex Doppler sonography in diagnosing hepatic venocclusive disease. We measured the blood velocity and flow in the portal vein, hepatic vein, and inferior vena cava of six patients who were histologically proved to have developed hepatic venocclusive disease after bone marrow transplantation. There were three men and three women with a mean age of 32 years (range, 21-44 years). Examination with Doppler sonography suggested the diagnosis a mean of 41 days (range, 11-62 days) after transplantation. In three patients, the diagnosis was suggested by reversed or "to and fro" flow in the portal vein. In the other three patients, the diagnosis was suggested by a decreased flow in the portal vein. One of these patients with decreased flow had subclinical hepatic venocclusive disease. In this patient, it was not the absolute level of flow but the decrease from a baseline established before ablative therapy that suggested the diagnosis. The amplitude of pulsatility in the hepatic veins appeared to decrease with the onset of venocclusive disease. In the hepatic veins and inferior vena cava, flow toward the heart was maintained. Our findings suggest that duplex Doppler sonography may be useful in detection of hepatic venocclusive disease. We speculate that, with wider experience, Doppler sonographic detection of decreased or reversed flow in the portal vein, in the proper clinical setting, may provide a noninvasive means of reliably diagnosing hepatic venocclusive disease in patients too ill to undergo liver biopsy.     

Peripheral arterial occlusive disease: prospective comparison of MR angiography and color duplex US with conventional angiography

Conventional angiography, two-dimensional inflow magnetic resonance (MR) angiography, and color duplex ultrasound (US) were performed on 12 patients in a blinded, prospective study. The ability to grade arterial lesions and plan revascularization interventions were compared. Arterial lesions were categorized as nonsignificant (0%-49% diameter reduction) or significant (50%-100% diameter reduction). Determination of nonsignificant and significant lesions with MR angiography was in agreement with that at conventional angiography in 100 of 140 lesions (71%). Agreement between results of conventional angiography and color duplex US occurred with 114 of 123 infrainguinal lesions (93%). Twenty-one vascular interventions were planned by using conventional angiography; there was agreement with color duplex US in 11 cases and MR angiography in five. Color duplex US performed well in the assessment of infrainguinal disease but was limited in the evaluation of iliac segments because of nonvisualization. The iliac region was visualized in more patients with MR angiography than with color duplex US, but image quality with MR angiography was inconsistent. Strategies to improve MR angiography of the peripheral vasculature merit further study.     

Hepatic blood supply: comparison of optimized dual phase contrast-enhanced three-dimensional MR angiography and digital subtraction angiography

PURPOSE: To optimize and determine the value of dual-phase contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography for preoperative evaluation of the blood supply to the liver. MATERIALS AND METHODS: Dual phase 3D MR angiography of the hepatic arteries and portal vein was performed in 140 patients. In 80 patients, the value of fat saturation, digital image subtraction, an anticholinergic agent, and a high-caloric meal were evaluated. In the next 60 patients, MR angiographic and digital subtraction angiographic (DSA) image quality and diagnostic value were compared. RESULTS: Fat-saturated images were of significantly better quality (P < .01) than non-fat-saturated images. Digital image subtraction was useful in only 23 of 40 patients. The injection of an anticholinergic agent was superfluous, whereas administration of a high-caloric meal helped in demonstration of the superior mesenteric artery and portal vein. Classification on MR angiograms of the arterial blood supply was correct in 57 of 60 patients. All arterial and portal venous lesions were seen on MR angiograms, and MR angiograms had a significantly higher subjective image-quality ranking than did DSA images in the evaluation of the portal vein (P < .05). CONCLUSION: Fat saturation and use of a high-caloric meal improve the results of MR angiography of hepatic vessels. MR angiography was comparable to DSA for evaluation of the arterial system and was superior for demonstration of the portal vein; therefore, MR angiography could replace intraarterial DSA.