Aneurysms of the portal vein and superior mesenteric vein

Only scattered reports of portal vein and superior mesenteric vein aneurysms appear in the literature. Case reports of three patients with portal vein and superior mesenteric vein aneurysms diagnosed by computed tomography (CT) and gray-scale, color Doppler, and duplex Doppler sonography are presented. In one case, an isolated portal vein aneurysm was demonstrated. In the second case, an aneurysm of the portal vein and superior mesenteric vein resulting in biliary ductal dilatation was observed. In the third case, an isolated superior mesenteric vein aneurysm was found. None of the patients had a history or clinical evidence of underlying liver disease, pancreatitis, or other disease states that would predispose them to the development of aneurysms. The clinical presentations, possible etiologies, and imaging features of portal vein and superior mesenteric vein aneurysms are reviewed. The value of CT and sonography in the detection and characterization of these rare aneurysms is discussed. Received: 29 February 1996/Accepted: 10 April 1996     

CT of the mesenteric vascular anatomy

Background: To evaluate the appearance of the arrangement of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) on computed tomography (CT) in normal patients and in patients with abdominal masses. Methods: One hundred seventy-seven consecutive abdominal CT examinations of 143 adults and two children were reviewed. The relationship of the SMV to the SMA was recorded at four locations: the beginning of the mesenteric vessels and levels 3 cm, 6 cm, and 9 cm caudad to the beginning. The relationship of the SMV to the SMA was divided into four quadrants in relation to the SMA: I, ventral right or directly ventral; II, dorsal right or directly right; III, dorsal left or directly dorsal; and IV, ventral left or directly left. Results: In the beginning of the SMV–SMA complex and levels 3 cm, 6 cm, and 9 cm caudal to the beginning, the SMV was located in quadrant I in 146, 84, 69, and 43 examinations, in quadrant II in 31, 93, 71, and 27 examinations, in quadrant III in zero, zero, five, and three examinations, and in quadrant IV in zero, zero, nine, and 15 examinations, respectively. The cases with SMV inversion had neither malrotation nor adjacent tumor compression. All the cases with an adjacent tumor-induced compression of the SMV–SMA complex had a normal SMV–SMA relationship. Conclusion: In the first 3 cm, the SMV is always to the right of the SMA. Caudal to the level of 6 cm, the SMV may be located to the left of the SMA without evidence of malrotation. A midgut nonrotation is more likely to be present when a proximal SMV inversion is coexistent with a rightward direction of the proximal jejunal vessels. A hypothetical depiction of the step-by-step change of the SMV–SMA relationship during embryologic development may explain the arrangement patterns of the mesenteric vessels in normal rotation and midgut nonrotation. Received: 6 May 1996/Accepted: 22 May 1996     

Three-dimensional CT imaging of an isolated dissecting aneurysm of the superior mesenteric artery

A case of an isolated dissecting aneurysm of the superior mesenteric artey is presented with findings of three-dimensional CT imaging. False lumen, intimal flap, entry, and re-entry are clearly identified on threedimensional CT imaging. Received: 27 April 1995/Accepted: 3 June 1995     

Portal vein absence and nodular regenerative hyperplasiaof the liver with giant inferior mesenteric vein

We present a patient with nodular regenerative hyperplasia of the liver (NRH) and portal vein absence studied with CT, MR imaging, and MR angiography. The most striking feature was exuberant hemorrhoids due to a giant hepatofugal inferior mesenteric vein. A relationship between unbalanced portal blood flow and nodular regenerative transformation of the liver is suggested in this patient. Received: 28 May 1996/Accepted: 10 July 1996     

Computed tomography of superior mesenteric vein thrombosis following appendectomy

During a 5-year period, superior mesenteric vein (SMV) thrombosis was detected with computed tomography (CT) in six patients shortly after an appendectomy. No sign of SMV was present at appendectomy, and a period of more than 2 weeks free of clinical symptoms had elapsed between the appendectomy and the onset of the SMV thrombosis. In four cases, the appendicitis was complicated. These patients had nonspecific signs and symptoms, although two of them had elevation of blood hepatic enzyme levels. In all cases, postcontrast CT demonstrated enlargement of the SMV, with well-defined enhancement of the vascular wall and an intraluminal clot. In one case, CT showed extension of the thrombus to the portal vein with the presence of low-attenuation areas in the liver, consistent with hepatic infarcts. Two patients had predisposing diseases: idiopathic hypersplenism in one case and chronic hepatic disease in the other. SMV thrombosis is a possible complication of appendicitis, and early appendectomy in appendicitis can prevent this complication. Moreover, as in any abdominal surgery, early appendectomy may be complicated by thrombosis of the SMV, thus creating problems of postoperative diagnosis. The complication is more frequent when the initial operation is performed under difficult conditions (peritonitis), or when the patient presents with a coagulopathy. CT is useful in the diagnosis of SMV thrombosis, thus leading to early management with anticoagulant therapy, with a view to avoiding complications such as intestinal ischemia, portal vein thrombosis, and hepatic infarction. Received: 19 March 1997/Accepted after revision: 15 July 1997     

A new criterion in differentiation of pancreatitis and pancreatic carcinoma: artery-to-vein ratio using the superior mesenteric vessels

Evaluation of infiltration of the superior mesenteric vein (SMV) and artery (SMA) fat planes has been considered in differentiating pancreatic carcinoma from pancreatitis. Some pancreatitis cases, however, can cause perivascular fat plane obliteration due to extension of the inflammatory process, mimicking appearances of carcinoma. This study investigated the diameters of SMV and SMA on CT scans, just caudal to the origin of SMA and portal confluens, in 68 pancreatitis and in 48 pancreatic carcinoma patients. SMA-to-SMV diameters (A/V diameter) were compared and ratios were obtained. In conclusion, it appears that when the A/V ratio is over 1.0, a malignant condition can be suspected. This may be used as a secondary criterion in the differential diagnosis of pancreatitis and pancreatic carcinoma. Received: 11 January 1995/Accepted after revision: 31 March 1995     

Percutaneous transluminal angioplasty in the treatment of chronic mesenteric ischemia: results and 3 years of follow-up in 23 patients

Background: We evaluated the clinical efficacy of visceral angioplasty in the treatment of chronic mesenteric ischemia. Methods: Over a 14-year period, we performed percutaneous transluminal angioplasty of 41 occlusive diseases of visceral arteries founded by angiography in 23 patients with chronic mesenteric ischemia. All but one (fibrodysplasic) stenoses were atherosclerotic, and 13 were localized in the ostial tract. Clinical follow-up was evaluated at 2, 6, 12, 24, and 36 months (mean follow-up = 27 months). Results: Angioplasty demonstrated a residual stenosis of 30% or less in 37 procedures, for a technical success rate of 90%. Seventeen of 20 patients had symptom remission after the first treatment, for a short-term clinical success of 77%; two patients needed a reangioplasty after 2 months, and one was referred for aortomesenteric bypass. During a mean follow-up of 27 months (range = 2–36), the clinical success was 88%; 2/15 patients underwent successful repeat angioplasty at 24 and 36 months, for a 100% secondary long-term clinical success. Only two minor complications were encountered. Conclusion: Although surgical results are undoubtedly positive, visceral angioplasty is justified in relation to both the high surgical mortality and the low incidence of complications arising from visceral angioplasty. Received: 31 October 1996/Accepted after revision: 2 April 1997     

Intraoperative US diagnosis of pylephlebitis (portal vein thrombosis) as a complication of appendicitis: a case report

We report a case of infectious thrombosis of the superior mesenteric vein (pylephlebitis) that was suspected preoperatively with computed tomography and confirmed at intraoperative ultrasonography as confined to the extrahepatic portal vein and superior mesenteric vein. Intraoperative ultrasonography revealed intraluminal echogenic thrombus material in the dilated superior mesenteric and extrahepatic portal veins, slightly dilated open splenic vein, and numerous venous collaterals in the hepatoduodenal ligament. When preoperative imaging studies are inconclusive, intraoperative sonography can confirm the correct diagnosis of pylephlebitis and may give valuable information about the extent of the thrombosis. Received: 19 December 1995/Accepted: 31 January 1996     

CT differentiation between necrotic and nonnecrotic small bowel in closed loop and strangulating obstruction

Background: The purpose of this study was to evaluate computed tomographic (CT) findings for predicting the presence of intestinal necrosis in patients with closed loop and strangulating obstruction of the small bowel. Methods: Twenty-five patients with surgically confirmed closed loop and strangulating obstruction were divided into two groups with (n= 16) and without (n= 9) intestinal necrosis. By using univariate and multivariate statistical procedures, we evaluated the differences in CT findings between the two groups on the basis of the following six findings: bowel dilatation of strangulated loops (bowel dilatation), wall thickening of strangulated intestines (wall thickening), ascites, vascular dilatation of affected mesenteries (vascular dilatation), elevation of mesenteric attenuation (mesenteric attenuation), and radial distribution of the mesenteric vessels (radial distribution). Results: Of the six findings, ascites, vascular dilatation, mesenteric attenuation, and radial distribution provided significant discriminating findings between the two groups on univariate analysis. On multivariate analysis, mesenteric attenuation was the most important discriminative factor, followed by radial distribution and ascites. Using these three parameters, the CT was correlated with the surgical findings in 15 of the 16 patients in the necrosis group (sensitivity = 93.8%) and in eight of the nine patients in the nonnecrosis group (specificity = 88.9%). The overall accuracy was 92.0%. Conclusions: Mesenteric attenuation, radial distribution, and ascites, depicted on CT differentiate well between necrosis and nonnecrosis of the small bowelin patients with closed loop and strangulating obstruction. Received 5 December 1997/Accepted: 14 January 1998     

Embolization of visceral pseudoaneurysms with platinum coils and N -butyl cyanoacrylate

Background: We evaluated the efficacy of transcatheter embolization in visceral artery pseudoaneurysms with platinum coils and N-butyl-cyano-acrylate (NBCA). Methods: Over the past 7 years, 20 patients were treated by transcatheter embolization in the same sitting with diagnostic angiography. Four right hepatic, one cystic, two gastroduodenal, one cavernosal artery, three superior mesenteric artery branch, and 11 renal artery branch pseudoaneurysms were included in the study. Results: Surgery was completely avoided in 19 patients. In the remaining patient with a superior mesenteric artery branch pseudoaneurysm, endovascular embolization was unsuccessful. Eighteen pseudoaneurysms were thrombosed with coil embolization alone. The remaining three pseudoaneurysms needed NBCA embolization. Two patients died from sepsis within 5 weeks after embolization. Conclusion: Emergent diagnosis and treatment are essential in visceral artery pseudoaneurysms because of the high rate of death. Transcatheter embolization with platinum coils is an efficient, safe treatment of choice. NBCA may be used to avoid proximal embolization of the visceral arteries that could not be catheterized selectively because of tortuosity, vessel size, or anatomic location. Received: 27 September 2001/Revision accepted: 16 January 2002     

Intestinal malrotation as an incidental finding on CT in adults

Background:Intestinal malrotation in adults is usually an incidental finding on computed tomography (CT). We present the CT findings of 18 adult patients with malrotation and discuss the clinical implications. Methods: Abdominal scans of 18 patients (12 women, six men; age range = 15–79 years) with intestinal malrotation were reviewed. Special attention was directed to the location of the superior mesenteric vessels, the location of the small and large bowels, the size of the uncinate process, the situs definition, and additional anomalies. Results: The malrotation was an incidental finding in all but one patient. The malrotation was type Ia in 17 patients and IIc in the one symptomatic patient. The superior mesenteric vessels were vertically oriented in 10, inverted in two, normally positioned in four, and mirror imaged in two cases with situs ambiguus. All patients had aplasia of the pancreatic uncinate process, five had a short pancreas, and two had a preduodenal portal vein. Fourteen patients had a normal situs and four had heterotaxia. Seven patients had polysplenia, six of which with associated inferior vena cava anomalies. Conclusions: Intestinal malrotation can be diagnosed on CT by the anatomic location of a right-sided small bowel, left-sided colon, an abnormal relationship of the superior mesenteric vessels, and aplasia of the uncinate process. Awareness of these abnormalities is necessary to diagnose this anomaly. It should be sought in patients with a situs problem, inferior vena cava anomalies, polysplenia, or preduodenal portal vein. Although usually an incidental finding, it is important to diagnose such a malrotation because it may cause abdominal symptoms. Also, knowledge of associated vascular anomalies is important when abdominal surgery is planned. Received: 1 October 1998/Revision accepted: 27 January 1999     

Abdominal involvement in neurofibromatosis 1: sonographic findings

Background: Neurofibromatosis 1 (NF1) has been studied from many viewpoints, but its abdominal involvement has rarely been reported. Sonography (US) is now the initial diagnostic tool for abdominal exploration, which prompted us to determine the clinical manifestations and US findings of abdominal involvement in NF1. Methods: We analyzed the US findings and clinical data of eight NF1 cases with abdominal involvement. Results: Abdominal involvement included neurofibromatous tumor growth in the liver, mesentery, and retroperitoneum, in addition to mesenteric leiomyomatosis and gastric carcinoma. Color Doppler US was useful not only in detecting blood flows in the lesions but also in preventing hazardous vascular injury during tumor biopsy. Conclusion: A better understanding of the clinical manifestations and US findings of abdominal involvement in NF1 translates into improved NF1 patient care. Received: 6 October 1999/Revision accepted: 26 January 2000     

Torsion of a wandering accessory spleen: CT findings

Torsion of an accessory spleen is a rare entity that can have a variable clinical presentation. We report the computed tomographic (CT) findings of an acute torsion of an accessory spleen in a 13-year-old girl. CT disclosed a hypodense mesenteric mass with peripheral inflammatory changes. Received: 20 November 1996/Accepted: 24 December 1996     

Small bowel varices: report of two cases

Two cases of small bowel (S-B) varices associated with portal hypertension, one with liver cirrhosis and one with portal thrombus, are reported. Detection of S-B varices has been a challenging task and several invasive diagnostic techniques have been used for this purpose. However, in our cases, color Doppler sonography revealed the S-B varices supplied by the superior mesenteric vein and draining to the iliac (one case) or ovarian vein (other case), which helped to establish an early appropriate diagnostic and treatment plan. Received: 19 March 1997/Accepted: 14 May 1997     

Portal vein opacification during ERCP in patients with pancreatitis

We report two cases of portal vein visualization during ERCP in patients with pancreatitis, one from inadvertent cannulation of the superior mesenteric vein, and in the other, through a preexisting fistula. Prompt recognition of this potentially significant event will obviate confusion and unnecessary prolongation of the procedure. Received: 9/9/96/Accepted: 10/16/96     

Portal tumor thrombus due to gastrointestinal cancer

Methods: We studied the clinical data of seven patients with portal tumor thrombus (PTT) due to gastrointestinal (GI) cancer to determine the radiologic patterns and clinical implications of this rare complication. Results: (a) PTT was located along the entire splenic vein in three cases, at the splenomesenteric confluence in one case, and in the superior mesenteric vein in one case. Intrahepatic PTT occurred in two of four cases with liver metastasis. (b) One cirrhotic case was complicated by the occurrence of colon cancer associated with PTT in the splenic vein; the esophageal varices became rapidly enlarged and poorly controlled, and the patient died due to repeated variceal rupture. (c) In all patients, abdominal sonography (US) detected PTT and color Doppler sonography confirmed the US findings. Conclusions: The splenic vein should be meticulously observed by color Doppler sonography to check for PTT in patients with GI cancer to improve patient care. Received: 29 December 1998/Accepted: 24 February 1999     

Hydatid hepatic cysts rupture into the biliary tract, the peritoneal cavity, the thoracic cavity and the hepatic subcapsular space: specific computed tomography findings

Background: This study attempts to demonstrate the role of computed tomography in the diagnosis of hepatic hydatid cyst rupture based on specific imaging findings and to propose combinations of the imaging findings diagnostic for specific types of rupture. Methods: Eleven patients were studied with computed tomography of the abdomen, with 4–8 mm slice thickness, after the oral administration of contrast material and intravenous contrast material in 6 cases. Results: Based on a combination of imaging findings the types of hepatic hydatid cyst rupture were: intrabiliary rupture in 7 patients, intraperitoneal rupture in 1 patient, intrathoracic rupture in 1 patient, hepatic subcapsular rupture in 2 patients. Structural deformity of the cyst was present in all cases, combined with: dilatation of the intrahepatic bile ducts (intrabiliary rupture); intraperitoneal fluid collections with diffuse haziness and stranding of the mesenteric fat (intraperitoneal rupture); an inhomogeneous lesion in the thorax with ipsilateral pleural effusion (intrathoracic rupture); a hydatid cyst located peripherally, with discontinuity of its adjacent to the hepatic capsule wall and subcapsular fluid collection (subcapsular rupture). The imaging findings were surgically and pathologically confirmed. Conclusions: Using combinations of specific imaging findings we correctly diagnosed the type of hepatic hydatid cyst rupture in all cases.     

Mesenteric cyst: sonographic findings

Background: Mesenteric cyst (MC) is a relatively rare disease, and its sonographic characteristics have not been sufficiently analyzed. Methods: We studied the sonographic findings of eight patients with MC, with attention paid to its size, shape, internal echoes, and especially the presence or absence of lateral shadowing and the mode of back echoes. In four cases, the sound velocity and acoustic impedance of cystic fluid were also measured. The mode of blood flow was evaluated by color Doppler sonography. Results: Six cases showed an oval or comma-shaped mass. Internal echoes were present in six cases, and two of them showed a pseudosolid pattern. In these cases, M-mode sonography confirmed the movement of these internal echoes. Only one case showed a posterior echo enhancement, and no case showed lateral shadowing. Sound velocity measured in four cases was 1515–1537 m/s, with an acoustic impedance of 1.550–1.576 kg/m²/s. No blood flow signals were obtained from the lesion. Conclusion: MC exhibits so many patterns on ultrasound that we should consider the possibility of MC when encountering an avascular oval mesenteric mass. Received: 30 August 1999/Accepted: 6 October 1999     

Median arcuate ligament syndrome with multivessel involvement: diagnosis with spiral CT angiography

Intestinal angina may be caused by compression of the celiac artery by the median arcuate ligament of the diaphragm. Aortography can suggest the diagnosis, but the diaphragm cannot be visualized by this examination. We report a symptomatic woman in whom spiral computed tomography-guided angiography demonstrated stenosis of the celiac artery, superior mesenteric artery, and both renal arteries due to diaphragmatic compression. Surgery was beneficial. Received: 15 August 1995/Accepted: 26 September 1995     

Portal vein thrombosis: CT features

There are many causative diseases to produced portal vein thrombosis (PVT) with the most common being liver cirrhosis with hepatocellular carcinoma. Visualization of abnormalities associated with PVT is crucial to diagnosis and appropriate intervention. Dynamic contrast enhanced CT is the best means of diagnosis of PVT and evaluation of various causative diseases. The findings of PVT of the dynamic CT are filling defect partially or totally occluding the vessel lumen and rim enhancement of the vessel wall. Signs and symptoms of PVT may be subtle or nonspecific and overshadowed by the underlying illness. Radiologists should be aware of the clinical situations that predispose a patient to portal or mesenteric vein thrombosis.