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.     

Portal venous system after portosystemic shunts or endoscopic sclerotherapy: evaluation with Doppler sonography

We sought to determine the usefulness of duplex Doppler sonography in the assessment of blood flow and clot formation in the portal vein in 44 patients with portal hypertension and bleeding esophageal varices who had undergone either endoscopic sclerotherapy (28 cases) or portosystemic shunt procedures (16 cases). The main, left, and right portal veins (collectively referred to as intrahepatic portal veins), superior mesenteric vein, splenic vein, and shunt were assessed for flow direction, presence of thrombi, and collaterals. Patent shunts were visualized in 12 (75%) of the 16 cases. Clot was detected in 27 (69%) of 39 intrahepatic portal veins in patients with end-to-side shunts, in six (67%) of nine intrahepatic portal veins in patients with distal splenorenal shunts, and in five (5%) of 92 intrahepatic portal veins in patients who had had endoscopic sclerotherapy. Flow in the main portal vein was hepatopetal in two (15%) of 13 patients with patent shunts (one end-to-side portacaval shunt and one distal splenorenal shunt). Flow in the main portal vein was hepatopetal in 26 (93%) of 28 patients who had had endoscopic sclerotherapy. Our data suggest endoscopic sclerotherapy preserves antegrade portal flow and results in fewer portal vein clots than surgical portosystemic shunts do. Patterns of thrombosis and flow direction vary unpredictably from patient to patient. Shunt patency should not be inferred without direct visualization of the shunt.     

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.     

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.     

Investigation of vesicoureteral reflux with colour Doppler sonography in adult patients with spinal cord injury

The aim of the study was to evaluate prospectively the performances of colour Doppler sonography for detection of vesicoureteral reflux in adult patients with neurogenic bladder due to spinal cord injury. One hundred eighty-seven adult patients who had developed neurogenic bladder due to spinal cord injury underwent retrograde cystography and sonographic evaluation by B-mode and colour flow Doppler sonography (CFDS). Results of both examinations were analyzed independently by two radiologists. Representative images of the sonographic evaluations were recorded on videotape and CD-Rom. CFDS detected reflux in 20 ureters while retrograde cystography revealed vesicoureteral reflux (VUR) in 25 ureters of a total of 374 ureters, which were examined by both methods. Sonography detected all cases of grades IV and V of reflux, 7 of 8 (87.5%) of grade III, 5 of 6 (83.3%) of grade II, and 4 of 7 (57.14%) of grade I. There were 6 false-positive and 5 false-negative findings with Doppler examination compared with retrograde cystography. Therefore, sensitivity and specificity of sonographic examination were 80 and 98.28%, respectively, with a positive predictive value of 76.92%. Colour flow Doppler sonography can play an important role in detection of VUR in spinally injured adult patients with neurogenic bladder and can be an effective imaging tool for follow-up.     

Value of Doppler sonography in revealing transjugular intrahepatic portosystemic shunt malfunction: a 5-year experience in 216 patients

OBJECTIVE: The purpose of the study was to evaluate the long-term clinical efficacy of Doppler sonography in revealing failure of transjugular intrahepatic portosystemic shunts (TIPS). SUBJECTS AND METHODS: During a 5-year period, 1192 Doppler examinations were performed in 216 patients with TIPS. No regular follow-up shunt venography was performed. Doppler examinations were retrospectively compared with the results of shunt revisions. Sonograms with negative findings were compared with the patients' clinical status so that the number of false-negative sonographic findings leading to an episode of shunt failure (recurrence of gastrointestinal bleeding or ascites) could be ascertained. Sonographic parameters assessed included diameter, velocity, flow volume, and congestion index of the portal vein; and shunt velocities. RESULTS: Doppler sonography revealed shunt occlusion in 25 of 26 angiographically proven cases (sensitivity, 96%). The combination of velocity criteria (peak intrashunt velocity > or =250 cm/sec, maximum velocity in the portal third of the shunt < or =50 cm/sec, or maximum portal vein velocity less than or equal to two thirds of the baseline value) revealed shunt stenosis in 103 of 110 cases (sensitivity, 94%). Doppler sonography missed a significant shunt stenosis that led to an episode of gastrointestinal bleeding or ascites recurrence in only seven cases. The congestion index of the portal vein showed significant differences between patent and malfunctioning shunts (p < 0.001). CONCLUSION: Doppler sonography is an effective primary imaging method for long-term follow-up of patients with TIPS.     

Hemodynamics of varicoceles: venous shunting in grade II and III varicoceles

In 42 consecutive patients with moderate (grade II) or large (grade III) left-sided idiopathic varicoceles, which were referred for percutaneous sclerotherapy, not only the reflux in the testicular vein but the venous drainage as well was studied by venography. As suggested by bidirectional Doppler sonography the reflux in the testicular vein is always associated with an upward (in physiologic direction) flow in these varicoceles. The draining veins are shown to be the deferential, cremasteric, external pudendal, or any combination of these. Thus, the grade II and III varicoceles are termed shunt-type varicoceles.     

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.     

Usefulness of echo-color Doppler in differentiating parathyroid lesions from other cervical masses

. The aim of our study was to clarify possible differential color Doppler US features between parathyroid lesions and other cervical masses. A total of 56 parathyroid lesions in 54 patients with primary hyperparathyroidism were preoperatively examined with color Doppler sonography. Color Doppler flow patterns were compared with those of 72 thyroid nodules and 20 cervical lymph nodes. In 38 parathyroid lesions a correlation between color Doppler patterns and size, location, and pathological findings was performed. Color Doppler sonography showed five vascular distribution patterns: pattern I, absence of flow; pattern II, focal peripheral flow (“vascular pole”) with arterial Doppler spectrum; pattern III, peripheral flow; pattern IV, internal flow (“parenchymal pattern”); pattern V, peripheral and intranodular flow. Pattern I was not specific for any cervical lesion considered. Conversely, pattern IV was observed solely in parathyroid lesions, and pattern II was observed in only one nonparathyroid lesion (thyroid nodule). Mixed pattern (pattern V) was observed solely in thyroid nodules. In addition, pattern III was a characteristic finding of thyroid nodules and was observed in only one parathyroid lesion. Color Doppler patterns of the parathyroid masses did not correlate with the size of the lesion or pathological findings, but only with the location of the gland. Our study showed that color Doppler assessment of parathyroid lesions is a useful integration of gray-scale US and may be helpful in distinguishing parathyroid lesions from other cervical masses. Received 6 November 1995; Revision received 9 January 1996; Accepted 19 February 1996     

Color Doppler sonography of the hepatic artery and portal venous system

Color Doppler sonography is an important noninvasive diagnostic tool for detecting abnormalities of the hepatic vasculature in patients with diffuse liver disease. To study its usefulness in these cases, we retrospectively reviewed the findings in 147 patients with abnormal portal venous color Doppler sonograms. This group comprised all patients with abnormal portal venous color Doppler sonograms studied from February 1987 to July 1989. Correlative imaging was not available in all cases. The sonographic diagnoses included (1) portal venous thrombosis (50 patients, 93 vessels); (2) portal-systemic or portal-portal collaterals (80 patients, 95 collaterals); (3) reversed, bidirectional, or other abnormal portal venous flow patterns (36 patients); and (4) abnormal hepatic arterial flow (20 patients). Since the results reported derive from a retrospective review without consistent correlation with other imaging studies, no appraisal of the sensitivity or accuracy of portal color Doppler sonography could be made from our data. The ability of color Doppler sonography to visualize flow without altering hemodynamics has led to several novel observations in these patients. These include increased arterial flow in states of low portal blood flow, reversal of portal flow direction postprandially, coincident reversed and hepatopetal flow in different branches of a single portal vein, and normal helical portal venous flow. These and other findings show that color Doppler sonography has enhanced our ability to detect abnormalities of the hepatic and portal venous system.     

Sonographic features of portal vein thrombosis

The ability of real-time sonography to demonstrate the liver venous network is well documented. Sonographic features of 21 cases of unsuspected portal vein thrombosis, detected by a screening sonography of the upper abdomen and subsequently confirmed by computed tomography, angiography, or surgery, are discussed. Sonographic features of portal vein thrombosis were an echogenic thrombus within the lumen of the vein (67%), demonstration of portal vein collateral circulation (48%), enlargement of the thrombosed segment of the vein (38%), and the so-called cavernomatous transformation of the portal vein (19%). Echogenic endoluminal thrombi were observed with the same incidences in malignant and benign disease. Sonography, unlike angiography, was unable to characterize neoplastic thrombi; only the combination of an echogenic thrombus and an adjacent hepatic mass was strongly suggestive of malignancy, especially hepatoma. The extensive use of sonography as a screening test in upper abdomen pathology will probably improve the detection of portal vein thrombosis, a diagnosis until now considered rare.     

Gradient echo MRI of portal vein thrombosis.

The MR appearance of thrombosis of the portal vein and its branches using gradient echo (GRE) sequences is described. The study consists of two separate parts. In the first part, five normal volunteers were examined to select the optimal section plane for each portal vessel to be studied. Given the "time of flight" effect of GRE sequences, a scan plane perpendicular to the direction of flow was used to obtain maximal signal enhancement of flowing blood. In the second part of the study, 13 patients with thrombosis of the portal system diagnosed by Doppler sonography, CT, and digital subtraction angiography were examined with the GRE technique. Gradient echo MR confirmed the presence and defined the extent of vessel thrombosis with high diagnostic accuracy. In addition, it proved accurate in detecting portosystemic collaterals. We concluded that the GRE technique can be effectively used as a complement to conventional SE MR to further delineate portal vessels.     

Congenital intrahepatic porto-systemic shunt.

An asymptomatic case of intrahepatic shunt between a portal and hepatic vein is presented. Ultrasound examination combined with Doppler sonography showed a communication between a dilated portal vein and a hepatic vein. Computed tomography and angiography confirmed the findings. Porto-hepatic venous shunting is very rare and has previously been reported in association with cirrhosis. The vascular malformation we present is believed to be a congenital anomaly, as no signs of cirrhosis or trauma were found.     

Duplex sonography of the splenoportal axis

48 patients with partial or complete portal vein thrombosis or tumor stenosis were examined by pulsed Doppler duplex scanning. In addition to the analysis of morphological changes, the pulsed Doppler duplex system yields functional data on the acceleration of blood flow in stenosis, flow in partial thrombosis and in differentiation between tubular cystic structures like arterial vessels, venous collaterals and dilated bile ducts. Qualitative and quantitative measurements of portal blood flow were performed in 55 cirrhotics and 15 healthy volunteers. Portal venous velocity and portal venous blood flow were significantly reduced in patients with cirrhosis. In 46 cases a hepatopetal blood flow was shown. In five cases a hepatofugal flow and in four cases a stagnant flow was found in the portal vein. Spontaneous portal systemic collaterals with hepatofugal flow were shown in 41% of cases. 11 patients with surgical portacaval shunts were examined. Patency was demonstrated in five patients where the anastomotic site was visible. Pulsed Doppler duplex sonography proved a valuable tool in the assessment of morphologic changes and revealed qualitative and quantitative data of portal venous hemodynamics.     

Pseudothrombosis with T2-weighted fast spin-echo MR images caused by static portal venous flow in severe cirrhosis

Unenhanced T2-weighted fast spin-echo images obtained in a 65-year-old woman with severe cirrhosis showed an area of high signal intensity occupying the left second-order portal vein branch, suggesting portal vein thrombosis in cirrhosis. Doppler sonography, which revealed virtually no blood flow in the vessel, also supported the diagnosis. Gadolinium-enhanced MRI subsequently revealed the patency of the vessel. The extremely slow portal venous flow was considered to be the cause of false-positive findings with unenhanced MRI and sonography.     

Contrast-enhanced color Doppler US in malignant portal vein thrombosis

Purpose: To assess the role of contrast-enhanced color Doppler US in the differential diagnosis of benign and malignant portal vein thrombosis.Material and Methods: Fifty-six patients with portal vein thrombosis underwent color and power Doppler US examination before and after i.v. injection of galactose-palmitic acid suspension. The criterion for diagnosing the presence and extension of thrombosis was the lack of visualization of portal vein flow in a segment of the portal vein. The criterion for diagnosing malignant portal vein thrombosis was the detection of pulsatile arterial flow, either hepatopetal or hepatofugal, in the thrombus. The US data were correlated with the types of portal vein thrombosis.Results: Among the 56 patients, there were 40 benign and 16 malignant portal thromboses. Unenhanced Doppler US detected continuous blood flow in 24 benign thromboses and pulsatile in 3 malignant thromboses. No flow, either continuous or pulsatile, was detected in 16 cases with benign thrombosis and in 13 cases with malignant thrombosis. Contrast-enhanced Doppler US allowed to assess pulsatile flow in 15 cases with malignant thrombosis (94%). The use of pulsatile flow as diagnostic criterion of malignant thrombosis yielded a sensitivity of 57% and a specificity of 95% with conventional Doppler US, whereas contrast-enhanced US achieved a sensitivity of 94% and a specificity of 100%.Conclusion: Contrast-enhanced Doppler US is a reliable diagnostic tool for assessing malignant portal vein thrombosis.     

Mesoatrial shunt for the treatment of Budd-Chiari syndrome: radiologic evaluation in eight patients

The construction of a mesoatrial shunt for portal decompression is one of the surgical procedures used for the treatment of Budd-Chiari syndrome. The results of the imaging procedures performed in eight patients treated in this fashion were retrospectively analyzed. All of the patients had angiography; seven had MR imaging and two had Doppler sonography. The demonstration of shunt patency, stenosis, or occlusion by MR and Doppler sonography was confirmed by angiography in all cases. We conclude that MR imaging may serve as an accurate screening method to assess shunt patency and to determine which patients require angiography to obtain hemodynamic data. Doppler sonography may also be a useful screening method, but additional data must be obtained to assess its role in evaluation of shunt patency.     

Portal hypertension: angiographic and hemodynamic evaluation

There has been a correlation of three hemodynamic parameters with the etiology of portal hypertension and one of the major determinants of therapeutic success, namely, the direction of portal flow. The presence of a 4 mm Hg or greater gradient between the right atrium and the intrahepatic inferior vena cava associated with a "lumpy" pull-back tracing between the wedged and free positions has been associated with alcoholic liver disease. Such patients have antegrade portal flow when their AoD/HWP ratio is in the range of 2.6 to 2.0, and flow becomes stagnant or reversed below this range. Nonalcoholic liver disease is characterized by the absence of a gradient between the right atrium and the inferior vena cava and by a pull-back tracing that falls smoothly and rapidly to the free hepatic vein value. These patients have antegrade portal flow with an AoD/HWP ratio in the range of 1.7 to 1.5. The correct characterization of the cause for diffuse liver disease and direction of portal flow applies to the selection process for patients being considered for the selective distal splenorenal shunt as well as for the newer procedure of orthotopic liver transplantation. It is hoped that the wider application of these physiologic parameters, in the context of an increasing array of imaging tools for the portal system, including high-resolution ultrasound, computed tomography, and magnetic resonance imaging (MRI), will continue to offer all clinicians interested in the problem of portal hypertension a reliable guide to prognosis and the success of the particular treatment provided.     

Early TIPS failure in association with left mesenterico-gonadal spontaneous portosystemic venous shunt; a case report

Transjugular intrahepatic portosystemic shunt (TIPS) periprocedural thrombosis rates have fallen significantly since the introduction of polytetrafluoroethylene-covered stent grafts. We present a case of a cirrhotic patient with portal hypertension presenting with early TIPS thrombosis in association with an underlying competing spontaneous left mesenterico-gonadal venous shunt, an uncommon variant of spontaneous portal systemic shunt (SPSS). The patient presented with bleeding distal duodenal varices refractory to endovascular therapy, and although a successful TIPS procedure was performed for this indication, early thrombosis was determined by follow-up abdominopelvic computed tomographic angiography (CTA) scan. Despite undergoing a standard TIPS revision procedure, blood flow through the TIPS remained hepatofugal. During a TIPS revision, portal vein angiography revealed competing large inferior mesenteric vein (IMV) varices shunting into the left renal vein via the left gonadal vein. The initial abdominal CTA was later reviewed by a non-invasive cardiovascular radiologist, and the presence of the competing left mesenterico-gonadal shunt was retrospectively identified. Radiologists interpreting CTA exams should be aware of SPSS generally and mesenterico-gonadal shunts specifically. Pre-procedural knowledge of underlying SPSS can affect post procedural outcomes and should be emphasized in the final CTA report.     

Color Doppler imaging of portosystemic shunts

This study was designed to investigate the utility of color Doppler sonography in the evaluation of portosystemic shunts. Thirty-one patients with a total of 32 shunts were imaged. The types of shunts examined included portacaval, five; mesocaval, eight; distal splenorenal (Warren), 14; and mesoatrial, five. Sonography was performed without knowledge of the status of the shunt, although the type of shunt was known before beginning the study. The sonographic studies were evaluated to determine their sensitivity and specificity on the basis of a prospective comparison with angiography or MR imaging (22 cases). The possible advantages of color Doppler over duplex Doppler sonography in evaluating portosystemic shunts were also investigated, as was the ability of color Doppler sonography to image specifically the shunt anastomoses. Color Doppler sonography successfully inferred shunt patency (17 cases) or thrombosis (five cases) in all 22 shunts for which correlative imaging was available (sensitivity = 100%, specificity = 100%). In comparing duplex with color Doppler sonography in all 32 shunts, the two techniques were almost equally effective in establishing patency in portacaval, mesocaval, and mesoatrial shunts. Duplex Doppler sonography, however, provided useful diagnostic information in only four of 14 splenorenal shunts. Color Doppler correctly inferred patency or thrombosis in all 14. Among all 32 shunts, the anastomosis was shown clearly by color Doppler in 23, probably in four, and not all in five. Our results suggest that color Doppler sonography is an excellent method for the evaluation of all varieties of surgically created portosystemic shunts. In particular, color Doppler sonography appears to be superior to duplex Doppler sonography in imaging splenorenal communications.