Intrahepatic portal venous variations: prevalence with US.

A prospective ultrasound study was undertaken to determine the prevalence of variants of the intrahepatic branching of the portal venous system. Of the 507 patients examined, 55 (10.8%) had trifurcation, 24 (4.7%) had a right posterior segmental branch arising from the main portal vein, 22 (4.3%) had a right anterior segmental branch originating from the left portal vein, and one (0.2%) had absence of the horizontal segment of the left portal vein. Not one patient had complete absence of the right portal vein in this series. The remaining 405 (79.9%) patients had normal distribution of the portal venous system; some patients of the normal group had minor variations in distribution.     

Portal venous variations. Prevalence with contrast-enhanced helical CT

PURPOSE: To review the distribution of intrahepatic portal venous branching in order to determine the prevalence of variations. MATERIAL AND METHODS: We made a retrospective review of 655 contrast-enhanced helical CT (CECT) images of patients referred to our department for upper abdominal CT examination during an 8-month period. Of the 655 patients, 70 were eliminated from the study because of improper opacification of the portal venous system. Variations of portal venous branching in the remaining 585 patients were classified. RESULTS: Of 585 patients, 504 (86.2%) had classical bifurcation of the main portal vein (MPV); 72 (12.3%) had a trifurcation of the MPV, 5 (0.9%) had a right anterior segmental branch originating from the left portal vein (LPV), 2 (0.3%) had an LPV originating from the right anterior segmental branch and 2 (0.3%) had a right posterior segmental branch arising from the MPV. CONCLUSION: Variations of portal venous branching are common and helical CT is efficacious in identifying these variations.     

肝内门静脉和肝静脉的解剖与变异(三维动态增强磁共振血管成像分析)

目的用三维动态增强磁共振血管成像（３ｄｉｍｅｎｔｉｏｎａｌｄｙｎａｍｉｃｃｏｎｔｒａｓｔｅｎｈａｎｃｅｄＭＲＡ,３ＤＤＣＥＭＲＡ）前瞻性地观测肝内门静脉（简称门脉）和肝静脉的解剖和变异。方法共进行１４２例门脉和肝静脉３ＤＤＣＥＭＲＡ检查。对肝内门脉和肝静脉的解剖和变异做分型,计算每一型所占总调查人数的比例,并计算右后下肝静脉的显示率。结果１４２次成像中,８例（５．６％）显示门脉呈三分叉状,７例（４．９％）门脉先分出右后支,然后上行分为左支和右前支,４例（２．８％）门脉右前支源于左支,未发现有门脉左支水平段或右支缺如,余下１２３例（８６．６％）显示正常门脉分支。绝大多数情况下（９５．１％）肝中、肝左静脉合并,而三大支肝静脉单独汇入下腔静脉仅占４．９％。右后下肝静脉的显示率为７．７％。结论肝内门脉变异并不少见。肝中和肝左静脉多合并后汇入下腔静脉。部分病人有较为粗大的右后下肝静脉。３ＤＤＣＥＭＲＡ能方便而清楚地显示上述血管的解剖和变异     

Anatomy of the right anterosuperior area (segment 8) of the liver: evaluation with helical CT during arterial portography

PURPOSE: To evaluate the segmental anatomy of the right anterosuperior area (segment 8) of the liver by using helical computed tomography during arterial portography (CTAP). MATERIALS AND METHODS: Twenty-seven patients without lesions at segment 8 underwent helical CTAP. Three-dimensional portograms were reconstructed to verify the course of the portal veins. The number of subsegmental branches, in addition to the branching point and the distribution in segment 8, was assessed. RESULTS: In 25 (93%) patients, the dorsal branch of segment 8 gave rise to dorsally directed branches posterior to the right hepatic vein. In only four (25%) of 16 patients in whom the medial branch of segment 8 arose near the porta hepatis, the long paracaval portal branch of the caudate lobe extended upward above the interval between the middle and right hepatic veins. CONCLUSION: In most of the patients, the dorsal branches of segment 8 supplied the dorsocranial area of the right lobe posterior to the right hepatic vein. The paracaval portion of the caudate lobe was limited to below the interval between the middle and right hepatic veins in the majority of patients who showed medial branches of segment 8 arising near the porta hepatis. Recognition of this vascular anatomy is clinically important for preoperative evaluation of hepatic tumors in segment 8 because it may contribute to a safer surgical approach.     

Intrahepatic portal venous system: variations demonstrated with duplex and color Doppler US

Seventeen cases of variations of the intrahepatic portal venous system were investigated with use of duplex and color Doppler ultrasound (US). Seven cases involved absence of the horizontal segment of the left portal vein, with portal supply to the left lobe arising from the right lobe. The 10 remaining cases involved variations of intrahepatic portal branching resulting from absence of the right portal vein, taking four patterns. It is thought that these findings represent variants of normal. These variants are important in two settings: in planning hepatic surgery and in the differential diagnosis of chronic portal vein thrombosis.     

Anatomy of intrahepatic portal branches visualized by three-dimensional imaging analysis of CT arterial portography

The purpose of this study was to clarify variations in intrahepatic portal branches by means of CT imaging procedures. The subjects were 73 patients, 59 men and 14 women, who ranged in age from 41 to 76 years, with a mean of 63 years. The procedures were as follows. The entire liver was scanned using helical CT during the portal and hepatic venous phases, and 3D images of the portal vein were reconstructed with the volume-rendering technique and the region-growing method. The CT unit was a HITACHI W2000, and the imaging analyzer a Sun Ultra 1. We found that the branching patterns of both the anterior (P5 and P8) and posterior segmental branches (P6 and P7) of the right lobe of the liver could be classified into four types. The caudate branch (P1) and left lateral segmental branches (P2 and P3) were classified into three types, and the interior segmental branch of the left lobe (P4) was classified into two types. The frequency of each pattern was also revealed. These branching types and their frequencies were generally the same as those described in previous reports. Thus, the portal anatomy visualized by these methods indicates that they could be very useful for preoperative examinations or IVR.     

Multi-detector row CT of relevant vascular anatomy of the surgical plane in split-liver transplantation

PURPOSE: To evaluate relevant arterial and venous anatomy of the hepatectomy plane lateral to segment IV by using multi-detector row computed tomography (CT) with respect to adult living related transplantation of the right lobe of the liver. MATERIALS AND METHODS: In potential liver donors, 100 consecutive hepatic CT angiograms were obtained after intravenous bolus administration of 150-180 mL of nonionic contrast material. Arterial phase images (1.25-mm collimation, 7.5 mm/ 0.8-second table speed) were acquired after test dose injection. Portal phase images were acquired at 60 seconds (2.5-mm collimation, 15 mm/0.8-second table speed). Postprocessing depicted arterial, portal, and hepatic vein anatomy traversing the anticipated surgical hepatectomy plane to the right of the middle hepatic vein (MHV) and separating the right and left lobes of the liver. Two radiologists interpreted the images, and data were agreed on by consensus. Data collected included intrahepatic anatomy and origin of the artery and vein supplying segment IV; the venous drainage from segments V and VIII; and the presence, size, and distance from the right hepatic vein (RHV) confluence of accessory hepatic veins in the surgical plane. RESULTS: Thirty-one donors had conventional hepatic vascular anatomy. Vessels that traversed the hepatectomy plane included the artery supplying segment IV in seven (7%) patients, dominant portal vein supply to segment IV from the right portal vein in two (2%) patients or from both right and left portal vein branches in three (3%) patients, segment VIII draining into the MHV in 67 (67%) patients or both the MHV and RHV in 18 (18%) patients (the major draining vein was >7 mm in diameter in 23%), segment V draining into the MHV in 10 (10%) patients, or both the MHV and RHV in 19 (19%) patients (the major draining vein from segment V was 7-10 mm in diameter in 70 patients, and larger than 10 mm in five). Forty-four accessory hepatic veins were identified in 40 patients; seven drained segment V, while the majority drained segments VI and VII. The mean diameter was 5.3 mm and 45% were larger than 6 mm. The average distance to the RHV-inferior vena cava confluence was 28.7 mm. Of 70 patients with drainage from segment V into RHV, 22 (31%) had an accessory RHV. However, atypical drainage into the MHV was noted in seven (70%) of 10 patients and into the MHV and RHV in 11 (58%) of 19 patients. CONCLUSION: In the majority of potential donors, CT angiography depicted a wide range of vascular anatomic variations that traverse the hepatectomy plane.     

Patent paraumbilical vein: anatomic and hemodynamic variants and their clinical importance.

Fifty-five of 353 patients with suspected portal hypertension studied with Doppler sonography had a patent paraumbilical vein. Of these 55 patients, 39 had the classic intrahepatic venous circulation found in Cruveilhier-Baumgarten syndrome: hepatopetal flow in all segmental portal veins and hepatofugal flow leaving the liver in a paraumbilical vein in the falciform ligament to join veins of the anterior abdominal wall. Sixteen patients had variants of the classic pattern: Flow in one or more segmental portal veins of the left lobe or the entire liver was hepatofugal. In addition, new venous channels connecting the left portal vein with the extrahepatic paraumbilical vein were found. Assessment of liver function with the Pugh score showed severe impairment in the majority of patients with a patent paraumbilical vein. Patients with the classic intrahepatic circulation had smaller esophageal varices than those with hemodynamic or anatomic variants. The presence of a patent paraumbilical vein did not prevent formation of esophageal varices in the patients studied.     

Bile duct injuries leading to portal vein obliteration after transcatheter arterial chemoembolization in the liver: CT findings and initial observations.

PURPOSE: To document the computed tomographic (CT) findings of transcatheter arterial chemoembolization (TACE)-induced, localized bile duct injuries leading to portal vein branch obliteration in the liver and to elucidate the clinical implications with retrospective review of the authors' experiences. MATERIALS AND METHODS: Follow-up CT scans obtained in 11 patients with TACE-induced intrahepatic bile duct dilatation were reviewed retrospectively to evaluate serial changes in the adjacent portal vein branches and hepatic parenchyma. Clinical data, including time between TACE and CT and serum alkaline phosphatase levels, also were analyzed. RESULTS: Of 11 patients with marked (n = 8) or mild (n = 3), lobar (n = 4) or segmental (n = 7) bile duct dilatation with or without bile collection in the tissue sheaths of the Glisson capsule or hepatic parenchyma, nine (82%) had bile duct changes at the first CT follow-up, within 1 month after TACE. Marked narrowing or obliteration of the adjacent intrahepatic portal vein branches in 10 (91%) patients resulted in progressive atrophy of the corresponding hepatic parenchyma in nine (82%) at variable times after TACE. The serum alkaline phosphatase level increased to more than 200 U/L in eight (89%) of nine patients 1 month after TACE. CONCLUSION: TACE-induced intrahepatic bile duct injury resulting in obliteration of the adjacent portal vein branch seems to be one cause of hepatic parenchymal atrophic changes after TACE.     

Aneurysms of the portal venous system: ultrasonography and CT findings

Objective: The retrospective study of aneurysms of the portal venous system and their possible aetiology, using different imaging methods. Material and methods: Between 1992 and 1995 we collected 13 cases of portal vein aneurysm from 11 patients, eight of whom suffered portal hypertension (PH) secondary to hepatic cirrhosis. All were diagnosed by means of ultrasonography (155) and/or computed tomography (CT). The aneurysms were defined as fusiform expansions when in the main portal vein and its branches or as cystic lesions with internal flow when in the intrahepatic branches. Results: Ten of the aneurysms (76.9%) were in the extrahepatic portal venous system and three (23.1%) in intrahepatic branches. Of the extrahepatic aneurysms, the two most common locations were the main portal vein and the confluence of superior mesenteric and splenic veins (30.7% each site). The largest were generally those at the confluence (37.6±9.7 mm maximum diameter). Conclusion: Aneurysms in the portal system can be congenital or acquired. Although their aetiology is uncertain, we found a clear relation to PH syndrome; of 13 aneurysms in the study, eight were related to this disease. PH should be suspected in the evaluation of portal aneurysms.     

Haemodynamic changes in the liver under balloon occlusion of a portal vein branch: evaluation with single-level dynamic computed tomography during hepatic arteriography

AIM: To assess haemodynamic changes in the liver under temporary occlusion of an intrahepatic portal vein. MATERIALS AND METHODS: Between February 2000 and October 2004, 16 patients with hepatobiliary disease underwent single-level dynamic computed tomography during hepatic arteriography (SLD-CTHA) under temporary balloon occlusion of an intrahepatic portal vein. All patients needed percutaneous transhepatic portography for therapy of their disease. SLD-CTHA was undertaken to clarify the time-attenuation curve influenced by portal vein occlusion, and it was performed continuously over a period of 30s. The difference in absolute attenuation of the liver parenchyma in segments with occluded and non-occluded portal vein branches was determined by means of the CT number, and the difference in absolute attenuation of the occluded and non-occluded portal veins themselves was also evaluated. RESULTS: SLD-CTHA demonstrated a demarcated hyperattenuation area in the corresponding distribution of the occluded portal vein branch. The attenuation of the liver parenchyma supplied by the occluded portal vein was significantly higher than that in the non-occluded area (p<0.01). The balloon-occluded portal branch enhancement in 15 of 16 cases (94%) appears due to arterio-portal communications. Failure to evaluate a remaining case for portal branch enhancement was due to absence of a visualized portal branch in the section. CONCLUSION: Under temporary occlusion of an intrahepatic portal vein, hepatic angiography produced enhancement of the occluded portal branches and their corresponding parenchymal distribution; this finding is considered consistent with the presence of arterio-portal communications.     

Congenital and acquired anomalies of the portal venous system.

Knowledge of the normal anatomy, most frequent variants, and congenital and acquired anomalies of the portal venous system is of great importance for liver surgery and interventional procedures such as creation of transjugular intrahepatic portosystemic shunts. Radiologic studies of the portal venous system include color Doppler ultrasonography (US), computed tomography (CT), magnetic resonance imaging, and arterial or direct portography. Among the most common branching variants of the portal vein are trifurcation, right anterior portal branch arising from the left portal vein, and right posterior portal branch arising from the main portal vein. Agenesis of the right or left portal vein is the most frequently reported congenital anomaly. Venous collateral vessels due to portal hypertension and cavernous transformation of the portal vein are best evaluated with cross-sectional imaging. Intrahepatic portosystemic, arterioportal, and arteriosystemic fistulas and associated perfusion anomalies have characteristic features at dual-phase helical CT. Color Doppler US is the single most useful tool for demonstration of aneurysms of the portal venous system and bland or neoplastic portal vein thrombosis. CT is also the best means of evaluating gas in the portal venous system, which is no longer an ominous sign and must be differentiated from aerobilia.     

三维CTAP对右肝静脉与右门静脉关系的研究

目的观察右门静脉第3级分支与右肝静脉的前后关系,阐明右肝静脉是否与右纵裂相一致,能够作为右前段和右后段的分界标志。方法观察连续100例门静脉显示良好无严重肝硬化的螺旋CT动脉性门静脉造影(CTAP)影像并行三维重建,对清楚显示右门静脉与右肝静脉关系的69例,对照观察三维CTAP和轴位CTAP影像。结果右门静脉第3级分支与右肝静脉关系的分析表明,在S8与S7之间近右膈顶的部分,右纵裂多数(54/64,84%)位于右肝静脉之背侧;在S5与S6之间,右纵裂经常(46/69,67%,约2/3)位于右肝静脉的腹侧。结论右肝静脉不是可靠的分界右前段和右后段的标志。门静脉的第3级分支是确定肝段的关键标志,提示应以门静脉第3分支P5～P8确定相应的肝段S5～S8,避免以右肝静脉为标志对肝段或肝肿瘤的错误定位。     

Spontaneous intermittent reversal of blood flow in intrahepatic portal vein branches in cirrhosis of the liver

The intrahepatic portal venous flow in cirrhosis of the liver was evaluated by percutaneous transhepatic portography and hepatic arteriography. Spontaneous reversal of flow in segmental portal vein branches was documented. Changes in hepatic arterial inflow and portal venous pressure may result in intermittent changes in the direction of flow in segmental portal venous branches within the cirrhotic liver. Segmental reversal of blood flow seems to be the precursor of total hepatofugal portal flow.     

门静脉3D DCE MRA成像的价值与常规门静脉造影对照研究

与常规门静脉造影对照,评价门静脉三维动态态增磁共振血管成像（３－ｄｉｍｅｎｓｉｏｎａｌｄｙｎａｍｉｃｃｏｎｔｒａｓｔｅｎｈａｎｅｄＭＲＡ,３ＤＤＣＥＭＲＡ）显示门静脉开放性及侧支循环的能力。材料与方法：共有２０例患者做了门静脉ＤＤＣＥＭＲＡ成像,分析门静脉３ＤＤＣＥＭＲＡ上门脉主干,肝内门脉     

Correlation of a defect of portal perfusion in the dorsal part of segment IV of the liver on CT arterial portography with inflow of the aberrant pancreaticoduodenal vein

The correlation between an aberrant pancreaticoduodenal vein and a portal perfusion defect in the dorsal part of segment IV as demonstrated on CT arterial portography (CTAP) was investigated. 14 patients with non-tumorous defects of portal perfusion in the dorsal part of segment IV of the liver parenchyma, shown on CTAP underwent CT during pancreaticoduodenal arteriography. The defect on CTAP was shown as an enhanced area resulting from non-portal venous inflow in eight (57%) of 14 patients on CT during pancreaticoduodenal arteriography. In conclusion, the non-portal venous supply via an aberrant pancreaticoduodenal vein occasionally causes a defect of portal perfusion in the dorsal part of segment IV on CT arterial portography.     

Hepatic lobar atrophy following obstruction of the ipsilateral portal vein from hilar cholangiocarcinoma

Gross deformity of the liver associated with hilar carcinoma is rare. In 17 patients with hilar cholangiocarcinoma and intrahepatic bile duct dilatation, the relationships between lobar or segmental atrophy, compensatory hypertrophy, and patency of portal vein branches were evaluated with computed tomography (CT) and angiography. All six patients with obstructed or narrowed portal veins (group A) had lobar or segmental atrophy on CT scans and angiograms. Compensatory hypertrophy was observed in the unaffected lobe with a patent portal vein in five. In contrast, neither hepatic atrophy nor hypertrophy was demonstrated in the other 11 patients with patent portal veins. All group A patients had differences in hepatic attenuation on CT scans or dense opacification during the hepatogram phase of angiography. Biliary decompression was optimized when the bile duct selected for percutaneous drainage paralleled a patent portal vein. Knowledge of radiologic findings will assist in determining the primary site along the bile duct from which carcinoma has arisen.     

Refractory biliary leak from intrahepatic biliary-enteric anastomosis treated by selective portal vein embolization

A 66-year-old woman underwent partial hepatectomy and pylorus-preserving pancreaticoduodenectomy for advanced Klatskin-type cholangiocarcinoma, and five intrahepatic biliary-enteric anastomoses were created. One anastomosis between the anterior-superior segmental bile duct and the jejunum developed a refractory biliary leak. Selective portal venous embolization with use of ethanol was performed in the anterior-superior portal branch to eliminate the production of bile by the target segment. The patient's clinical course was uneventful and the leak resolved after portal vein embolization.     

Usefulness of a saline flush for intravenous 3-dimensional computed tomography portography using multidetector-row helical computed tomography

PURPOSE: To evaluate the clinical usefulness of a saline flush technique in improving the imaging quality of 3-dimensional computed tomography portography (3D-CTP). METHODS: To evaluate liver metastases, 58 patients were divided into 2 groups undergoing 3D-CTP with or without a saline flush. The computed tomography (CT) values of the right portal vein (RPV), left portal vein (LPV), main portal vein (MPV), and right hepatic parenchyma (RHP) were assessed. Maximum intensity projection (MIP) 3D-CTP images were evaluated by vessel visualization. RESULTS: Higher mean CT attenuation values in the RPV, LPV, MPV, and RPV-RHP were observed in the saline flush group and were statistically significant (P = 0.04, P = 0.03, P = 0.01, and P = 0.04, respectively). The difference in imaging quality between 2 groups was statistically significant (P = 0.04). In segment VIII, the ability to depict the segmental branches was significantly higher when the saline flush technique was used (P = 0.03). CONCLUSIONS: The saline flush technique increases the CT attenuation values of the portal vein and the difference in values between the portal vein and the tissue around it and improves the MIP imaging quality of 3D-CTP.     

Hepatic arterioportal shunts not directly related to hepatocellular carcinoma: findings on CT during hepatic arteriography, CT arterial portography and dual phase spiral CT

AIM: To evaluate findings of arterioportal shunts not directly related to hepatocellular carcinoma (HCC) which were seen within third-order portal branches on computed tomography (CT) during hepatic arteriography (CTHA), arterial portography (CTAP), and dual phase spiral CT.MATERIALS AND METHODS: At CTHA in 112 patients, we examined third-order portal vein branches to find arterioportal shunts not directly related to HCC. Six cases were found. We evaluated the findings of these shunts on CTHA and investigated whether CTAP (n = 6) and dual phase spiral CT (n = 5) showed perfusion defects in the corresponding areas on arterioportal shunts. RESULTS: Five of six cases showed abrupt visualization of portal branches without visualization of the proximal portion of CTHA. Five of six cases showed no perfusion defect on CTAP and no hyperattenuating area on CTHA. Four of five cases showed no hyperattenuating area on hepatic arterial phase spiral CT. CONCLUSION: Arterioportal shunts not directly related to HCC and occuring within third-order portal branches mainly showed abrupt visualization of portal branches on CTHA. These occurred frequently without perfusion defects on CTAP and without a hyperattenuating area on CTHA and hepatic arterial phase spiral CT.Park, C. M. (2000). Clinical Radiology55, 465-470.