Aneurysms of the portal venous system: Gray-scale and color doppler ultrasonographic findings with CT and mri correlation

Two cases of incidentally detected aneurysms involving the portal venous system are described with emphasis on gray-scale and color Doppler ultrasonographic (US) findings. Appearing on US as anechoic masses showing direct luminal continuity with the right portal vein and superior mesenteric vein, the lesions displayed spectral findings characteristic of portal venous system on color Doppler US. Dynamic helical computed tomography (CT) demonstrated simultaneous enhancement with the portal system, while the aneurysms were hypointense owing to flow void on T1-weighted spin-echo magnetic resonance (MR) images.     

Congenital and acquired abnormalities of the portal venous system: multidetector CT appearances

A knowledge of normal anatomy as well as the most frequent variants and abnormalities of the portal venous system are of great importance for liver surgery and interventional procedures. An understanding of the varied MDCT appearances of these abnormalities will allow more definitive diagnoses and help avoid false diagnoses.     

Traumatic trapped penis: ultrasonography and CT findings

We report the case of an 18-year-old man who presented with traumatic trapped penis after a motorcycle accident. Ultrasonography (US) and CT scan disclosed a trapped penis buried within the prepubic fat. Imaging findings of the traumatic trapped penis and the role of imaging study for this rare clinical condition are discussed.     

CT of portal venous occlusion.

Thrombosis of a portion of the portal venous system can be directly imaged by contrast-enhanced CT as a low-attenuation lesion within the involved portal venous segment with or without expansion of the vessel or enhancement at the margin of the thrombus. Collateral venous pathways are often evident, which provide supporting evidence of the occlusion. Alterations in portal venous blood flow lead to metabolic disturbances in the liver and to abnormalities in parenchymal enhancement during dynamic CT scanning, and these changes are manifested as abnormalities in hepatic parenchymal density. The detection of portal venous thrombosis or occlusion, collateral veins, or abnormal liver enhancement should initiate a search for the diseases that cause these abnormalities.     

Giant varices in portal hypertension: CT findings

Two cases of giant varices in portal hypertension are presented. Dynamic computed tomography (CT) was useful in establishing that the masses were in fact dilated veins.     

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.     

Calcifications in the portal venous system: comparison of plain films, sonography, and CT.

We describe 10 patients with long-standing portal hypertension and calcifications in the splenoportal and mesenteric venous systems or collateral vessels. The patients were examined with abdominal plain films (n = 10), sonography (n = 10), and CT (n = 9). Calcium was seen on CT scans in nine cases, on sonograms in seven, and on abdominal plain films in five. Calcifications appeared to be located in the wall of the vein in all cases. Sites of detection included the main portal, splenic, superior mesenteric, coronary, and peripancreatic veins. CT was more sensitive than sonography, and both were more sensitive than plain films, in showing portal venous calcification. Detection of such calcifications may influence surgical or percutaneous therapy of portal hypertension.     

Evaluation of hepatic venous pulsatility and portal venous velocity with Doppler ultrasonography during the puerperium.

OBJECTIVE: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. METHODS AND MATERIAL: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. RESULTS: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. CONCLUSION: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period.     

后肾腺瘤CT及超声表现三例

后肾腺瘤(metanephric adenoma,MA)是一种十分罕见的肾原发良性肿瘤,常被误诊为肾癌,熟悉该病的影像表现对于患者手术方案的制定有重要意义.笔者搜集3例MA并复习文献后报道如下.     

Imaging findings in incidental intrahepatic portal venous shunts

OBJECTIVE: The purpose of our study was to describe the imaging findings in incidentally discovered intrahepatic portal venous shunts. CONCLUSION: Intrahepatic portal venous shunts are uncommon hepatic vascular anomalies that are often not associated with manifestations of liver disease or symptoms. They are most often solitary and in the left hepatic lobe. Identification of 25 intrahepatic portal venous shunts at a single institution over 6 years suggests that they may be more common than previously known and that with an increasing use of imaging, they may be identified more often in the future.     

Duplex sonography of the portal venous system: pitfalls and limitations

Duplex pulsed-Doppler sonographic examinations of the portal venous systems of 14 patients were reviewed, and the results were compared with the findings of other examinations including endoscopy and angiography. The sonograms of virtually every patient in the sample showed at least one of four pitfalls. The "mirror-image" artifact, in which the Doppler signal contained simultaneous and symmetric elements on both sides of the zero baseline, was identified in 11 patients (79%). The "flip" artifact, in which the Doppler signal would either flip from one side of the zero baseline to the other or would indicate a direction of blood flow opposite to that normally expected, was seen in six patients (43%). In four patients (29%), a Doppler flow signal could not be obtained from small vessels that were identified on standard real-time images. In 10 patients (71%), important vascular channels including bleeding gastroesophageal varices were obscured by bowel gas, ascites, or the patient's body habitus. Duplex sonography may still provide useful information about portal venous hemodynamics. However, it remains a prodigious technical undertaking whose accuracy can be severely hampered by artifacts and inherent technical difficulties.     

MR imaging of portal venous thrombosis: correlation with CT and sonography

Fourteen patients with portal venous thrombosis (PVT) diagnosed by CT and/or sonography were studied with MR. Three of the 14 had portal hypertension. The MR findings were compared with those of eight patients with portal hypertension, but without CT or sonographic evidence of PVT. MR imaging showed portal venous thrombosis in all 14 PVT cases. Intraluminal thrombi of less than 5 weeks duration appeared markedly hyperintense relative to liver and muscle on both T1- and T2-weighted images. Older thrombi appeared hyperintense relative to liver and muscle in eight of 11 cases, but only on T2-weighted images. MR showed thrombi in 11% more portal vessels than did CT (MR = 30, CT = 27) and in 28% more vessels than did sonography (MR = 32, sonography = 25). MR also showed 24% more collateral vessels than did CT (MR = 31, CT = 25) and 50% more vessels than did sonography (MR = 33, sonography = 22). Third-echo images (echo time = 96 msec, repetition time = 1500-2150 msec) verified the presence of venous thrombi in 28 (93%) of 30 PVT vessels, and they differentiated flow-related intravascular signal from true thrombi in six (17%) of 36 portal hypertension vessels. We conclude that MR is a valuable tool for imaging portal vein thrombosis. MR is a good substitute for CT and can be more informative than sonography.     

Thoracic collateral venous channels: normal and pathologic CT findings

Opacification of thoracic collateral venous channels (CVC) on chest CT is considered a useful sign of superior vena cava (SVC) obstruction, although its lack of specificity has occasionally been emphasized. We compared the degree of opacification of six various thoracic CVC in a group of 36 patients with SVC syndrome and in a control group of 50 patients; a dynamic incremental CT technique with bolus injection was used. Opacification of at least one CVC is inaccurate for the diagnosis of SVC obstruction, with a false-positive and false-negative rate of 34 and 31%, respectively. Only the opacification of the subcutaneous anterior channel provides a good specificity (96%), significantly higher (p less than 0.05) than that observed for the posterior collateral channels. In patients in whom the clinical records and other direct CT signs of vena cava obstruction are doubtful or absent, opacification of a subcutaneous anterior channel on chest CT should lead to a suspicion of obstruction of the SVC and cavography should be performed.     

Anomalous venous connections involving the portal system

Five cases representing four different venous anomalies involving the portal system are described. The clinical importance of these anomalies, especially in patients with portal hypertension, is stressed.     

Dual phase helical CT versus portal venous phase CT for the detection of colorectal liver metastases: correlation with intra-operative sonography, surgical and pathological findings

AIM: To assess whether dual phase helical computed tomography (DPCT) of the liver improves the detection of colorectal liver metastases compared with portal venous phase (PVP) imaging alone. MATERIALS AND METHODS: DPCT was performed in 33 consecutive patients before laparotomy for resection of colorectal liver metastases. CT comprised 8-mm slice collimation with a pitch of 1 to 1.25; imaging was commenced 20-25 and 65-70 s after the start of injection of 150 ml of contrast medium at 5 ml/s to coincide with hepatic arterial phase (HAP) and PVP contrast enhancement, respectively. Four blinded observers independently reviewed the HAP, PVP and DPCT images recording the site and size of all lesions. Alternative-free response receiver operating characteristic (AFROC) methodology was used to analyse the results, which were correlated with surgery, intra-operative ultrasound and histology. RESULTS: The mean observer sensitivities for malignant lesion detection were 75.3% for DPCT, 69.7% for PVP imaging and 66.7% for HAP imaging alone. There was a statistically significant improvement in malignant lesion detection using DPCT when compared with PVP imaging alone (P < 0.05). The mean areas under the AFROC curves were 0.84 for DPCT and 0.82 for PVP (P < 0.03) imaging alone. CONCLUSION: The detection of colorectal liver metastases was marginally better with DPCT than with PVP imaging alone, but the discovery of additional lesions did not affect the management of any of the patients in this study.