Proximal Superior Mesenteric Vein Research Articles

Prevalence and Risk Factors for Portal Cavernoma in Adult Patients with Portal Vein Thrombosis.

Portal vein thrombosis (PVT) represents a restriction or occlusion of the portal vein by a blood clot, which can appear in liver cirrhosis, inherited or acquired thrombophilia, malignancies, abdominal infection, abdominal inflammation, and injury to the portal vein; it can evolve to local venous extension, recanalization, or portal cavernoma (PC). This research represents an observational study of patients admitted with a diagnosis of PVT between January 2018 and December 2022. We assessed the rate of and risk factors for PC. In total, 189 patients with PVT were included; the rate of PC was 14.8%. In univariate and multivariate analysis, the main risk factors for the presence of PC were etiology (thrombophilia, myeloproliferative disorders, local inflammatory diseases, and idiopathic causes), prior PVT, and complete versus incomplete or single-branch portal obstruction. In patients with superior mesenteric vein (SMV) thrombosis, distal obstruction was more prone to PC than proximal obstruction. The main predictive factors were etiology, prior PVT, complete PVT obstruction, and no prior non-selective beta-blocker (NSBB) use; in patients with SMV thrombosis, the distal extension was more significantly associated with the risk of PC. We propose a composite score for the prediction of PC which includes etiology, prior diagnosis of PVT, prior NSBB use, complete versus incomplete PVT, and distal versus proximal SMV thrombosis, with good accuracy (AUC 0.822) and an estimated sensitivity of 76.92% and specificity of 82.39% at a cut-off value of 4.

S2694 An Uncommon Cause of Upper Gastrointestinal Bleeding

Introduction: We present a case of GI bleeding due to a direct communication between a pancreatic fistula and the splenic vein. Case Description/Methods: A 55 year-old female with a history of endometrial cancer, superficial lower extremity thrombus, and alcohol use presented with abdominal pain and dark red blood in her stools requiring blood transfusion. She reported recent ibuprofen use. An upper endoscopy showed small esophageal varices without red wales or stigmata of recent hemorrhage. A CT demonstrated extensive subacute thrombosis of the right and left portal veins, main portal vein (PV), proximal superior mesenteric vein (SMV) and splenic vein (SV). The pancreas appeared atrophic and contained small cysts. There was small ascites. Liver biopsy demonstrated mild steatohepatitis without fibrosis. She underwent placement of a transjugular intrahepatic portosystemic shunt (TIPS) with thrombectomy from the PV, SMV, and SV and was started on anticoagulation. Due to bleeding recurrence, she underwent TIPS revision with tPA injection and additional mechanical thrombectomy. Subsequently on an ultrasound, TIPS thrombosis was again noted and during TIPS revision, a communication was noted between the pancreatic duct and splenic vein, finally identifying the likely source of bleeding. A splenic vein stent was placed. Discussion: This case highlights an uncommon cause of upper GI bleeding and reinforces the importance of keeping a broad differential diagnosis for a patient with portal hypertension. Our patient had a complicated course with 2 TIPS revisions and esophageal varices, but the source of her bleeding was neither variceal nor mucosal. (Figure) Splenic vein thrombus can result as a complication of pancreatitis and subsequently lead to “sinestrial” (left-sided) portal hypertension and the formation of gastric varices which can also present with gastrointestinal bleed (GIB). Our patient did not have the classic finding of sinestral portal hypertension associated with SV thrombosis: gastric varices. Furthermore, during her initial TIPS placement and even her initial thrombectomy, no pancreatic fistula was observed. Although not always visualized due to the intermittent nature of bleeding, hemosuccus pancreaticus in the setting of chronic alcoholic pancreatitis most commonly involves the splenic artery (60-65%) and less commonly involves the gastroduodenal artery. Our patient’s case is unusual because angiogram demonstrated direct communication between a pancreatic fistula and the splenic vein, not the splenic artery.Figure 1.: Large clot burden at superior mesenteric vein.

S1420 A Rare Case of Superior Mesenteric Vein Thrombosis as a Complication of Pancreatic Pseudocyst Fistulization

INTRODUCTION: Superior Mesenteric (SMV) Thrombus is a rare complication of acute pancreatitis, and multiple factors contribute to its formation, including underlying inflammatory along with venous compression leading to venous stasis. Here, we present a unique case of an SMV thrombus as a result of a pancreatic pseudocyst to SMV fistula in the setting of chronic pancreatitis. CASE DESCRIPTION/METHODS: Patient is a 61-year-old male with a past medical history significant for chronic pancreatitis secondary to chronic alcohol abuse who presented with multiple episodes of nausea and non-bloody, non-bilious vomiting. Labs were notable for a lipase of 161 U/L and an alcohol level >300 mg/dL. Interestingly, the patient denied any abdominal pain, and the physical exam was unremarkable, with a soft, non-tender, non-distended abdomen noted with active bowel sounds. Computed Tomography (CT) Abdomen showed chronic calcific pancreatitis with a 2.5 cm hypodense pancreatic head mass with a proximal SMV thrombosis. Magnetic Resonance Imaging (MRI) Abdomen noted the mass to be a pseudocyst rather than a primary pancreatic malignancy with visualization of a wide connection between the cyst and the adjacent SMV with resultant thrombosis of the SMV, compatible with fistulization. Furthermore, imaging did not reveal acute pancreatitis, attributing visualized fat stranding to the thrombus. Surgery recommended initiation of anti-coagulation, therefore the patient was started on a heparin drip and discharged on apixaban with close surgical follow-up. DISCUSSION: Splanchnic vein thromboses are seen in less than 2% of patients with acute pancreatitis, the majority of these involving the splenic vein, and rarely, the SMV. The pathogenesis for these thrombi is thought to be from the combination of direct damage to the venous wall by freed pancreatic enzymes and compression of the vein by the inflamed pancreas. SMV thrombosis is often diagnosed incidentally on imaging, however, it has a high mortality rate of up to 20–50% due to the risk of small bowel ischemia, therefore anti-coagulation should be considered in these cases. Uniquely in our case, the pathogenesis of the SMV thrombus included a fistula between the pancreatic pseudocyst and the SMV, which has been scarcely reported, in the setting of chronic pancreatitis rather than an acute flare. Our case also warrants the question regarding the utility of longitudinal follow-up with serial imaging in those with chronic pancreatitis to prevent fatal outcomes, including bowel ischemia.Figure 1.: CT Abdomen W Contrast 3 cm round mass is seen in the pancreatic head [red arrow], with peripheral calcifications indicating chronic pancreatitis [green arrow]. The Superior Mesenteric Vein (SMV) is in close proximity with the pancreatic mass [yellow arrow].Figure 2.: MRI Abdomen W WO Contrast (T2WI AXIAL) Revisualization of the mass in the pancreatic head with dependent debris [red arrow]. There is also fistulization from the pseudocyst into the superior mesenteric vein (SMV) [green arrow].Figure 3.: MRI Abdomen W WO Contrast (T2WI CORONAL) Mass in the pancreatic head is T2 hyperintense without wall nodularities, clearly constituting a cyst [red arrow]. There is fistulization into the Superior Mesenteric Vein (SMV) [green arrow] followed by thrombosis [blue arrow].

Outcomes and complications for portal vein or superior mesenteric vein injury: No improvement in the era of damage control resuscitation

IntroductionPortal vein (PV) and superior mesenteric vein (SMV) injuries are lethal. We hypothesised outcomes have improved with modern trauma care. MethodsWe reviewed patients presenting to our Level 1 trauma centre over ten-years with PV/SMV injuries, analysing physiology, operative management, associated injuries, and outcomes. ResultsTwenty-four patients had 7 PV and 15 SMV injuries, 2 had both; all had operative exploration. Sixty-seven percent had penetrating trauma. While many had normal vitals, profound acidosis was common. All patients had ≥2 additional abdominal injuries, liver most common (50%). Additional abdominal vascular injuries were more common in non-survivors than survivors: IVC 46% vs 22%, common hepatic artery 20% vs 0%, SMA 26% vs 11%. The mean injury severity score (ISS) was 32.4, and the mean new injury severity score (NISS) was 44.5. Mortality was 63%. Eleven patients died from exsanguination, two from SMV thrombosis, and two from sequelae of other injuries. All survivors had venorrhaphy, as did 8 non-survivors. Non-survivors were also shunted; had ligation; or bypass, shunting, and ligation. Three exsanguinated prior to repair. Two survivors had SMV related complications. One with proximal SMV injury developed severe venous congestion and multiple enterocutaneous fistulae. Another developed an arterioportal fistula, managed with embolisation and percutaneous portal vein stenting. ConclusionDespite advances (REBOA, damage control surgery and resuscitation, liberal use of ED thoracotomy), PV and SMV injuries remain lethal. Injuries to other structures are ubiquitous. Early exsanguination is the major cause of death. All survivors had successful venorrhaphy; those who required more complex repairs died. Compromised mesenteric venous flow causes morbidity and mortality.

Evaluation and management of acute and chronic portal vein thrombosis in patients with cirrhosis.

Evaluation and management of acute and chronic portal vein thrombosis in patients with cirrhosis.

Extensive Thrombosis in a Patient with Familial Mediterranean Fever, Despite Hyperimmunoglobulin D State in Serum - First Adult Case in Korea

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent episodes of fever accompanied by peritonitis, pleuritis, arthritis, or erysipelas-like erythema. It is known to occur mainly among Mediterranean and Middle Eastern populations such as non-Ashkenazi Jews, Arabs, Turks, and Armenians. FMF is not familiar to clinicians beyond this area and diagnosing FMF can be challenging. We report a 22-yr old boy who presented with fever, arthalgia and abdominal pain. He had a history of recurrent episodes of fever associated with arthalgia which would subside spontaneously or by antipyretics. Autosomal recessive periodic fever syndromes were suspected. Immunoglobulin D (IgD) level in the serum was elevated and DNA analysis showed complex mutations (p.Glu148Gln, p.Pro369Ser, p.Arg408Gln) in the MEFV gene. 3D angio computed tomography showed total thrombosis of splenic vein with partial thrombosis of proximal superior mesenteric vein, main portal vein and intrahepatic both portal vein. This is a case of FMF associated with multiple venous thrombosis and elevated IgD level. When thrombosis is associated with elevated IgD, FMF should be suspected. This is the first adult case reported in Korea.

Superior Mesenteric Vein Occlusion Causing Severe Gastrointestinal Haemorrhage in Two Paediatric Cases

Reports about superior mesenteric vein thrombosis in childhood are very rare and have not been associated with gastrointestinal bleeding. We describe two cases of severe bleeding from the upper and lower gastrointestinal tract in children who had undergone complex abdominal surgery at considerable time before. The first child had a tracheoesophageal fistula, corrected by division, gastrostomy insertion, and repair of duodenal rupture. The child presented with severe bleeding from the gastrostomy site and was diagnosed with a thrombosis of the proximal superior mesenteric vein. The second child had a gastroschisis and duodenal atresia, and required duodenoplasty, gastrostomy insertion, hemicolectomy, and adhesiolysis. The child presented with intermittent severe lower gastrointestinal bleeding, resulting from collateral vessels at location of the surgical connections. He was diagnosed with a thrombosis of the superior mesenteric vein. In both children, the extensive previous surgery and anastomosis were considered the cause of the mesenteric thrombosis. CT angiography confirmed the diagnosis in both cases, in addition to characteristic findings on endoscopy. Paediatricians should suspect this condition in children with severe gastrointestinal bleeding, particularly in children with previous, complex abdominal surgery.

Postoperative Course after Simple Ligation for Superior Mesenteric Vein Injury Caused by Blunt Abdominal Trauma: Report of a Case

Traumatic injury of the superior mesenteric vein (SMV) by blunt trauma is a rare but frequently fatal injury. Although simple ligation should be considered for a patient in unstable condition, its complications have not been reported in detail. A 47-year-old man was struck on the abdomen during a fight. When he was transferred to a local hospital, he complained of severe abdominal pain. Computed tomography (CT) of the abdomen showed fluid accumulation in the peritoneal cavity and a hematoma around the root of the mesentery, with leakage of contrast material. When the patient was transferred to our emergency department, the hemodynamic status did not improve after rapid fluid resuscitation with 1,500 mL of crystalloid. Emergency laparotomy was performed 4 hours after the injury. Two lacerations of the proximal SMV were observed. The SMV was ligated owing to the unstable hemodynamic status. On postoperative day (POD) 5, abdominal radiography showed dilated loops of bowel, suggesting ileus of the small bowel. A CT scan with contrast enhancement showed that the wall of the small bowel was thickened. On POD 11, a CT scan showed that the collateral vessels that drain the mesenteric circulation had not developed. However, collateral vessels were revealed on a 3-dimensional CT scan, and, on POD 23, a CT scan showed that the collateral vessels had developed. The patient was discharged on POD 37. This case demonstrates that simple ligation of the proximal SMV leads to the development of collateral vessels and is useful for preventing side effects and improving outcomes.

Modified technique of meso-Rex shunt in case of insufficient length of the jugular vein graft

Meso-Rex shunt (MRS) can relieve portal hypertension and restore a physiological portal flow in patients with portal vein thrombosis. We describe a technical variant where the autologous internal jugular vein (IJV) was too short to bridge the superior mesenteric vein (SMV) and the Rex recessus. Patient A 15-year-old boy with portal cavernoma had several episodes of gastrointestinal bleeding despite repeated sclerotherapy. Preoperative assessment, including retrograde transjugular portography, showed persistent esophageal and gastric varices, severe hypertensive gastropathy, obstructed portal vein, patent SMV and splenomesenteric confluence, patent intrahepatic portal branches, and normal transhepatic pressure gradient. An MRS was planned. The left IJV was retrieved from its infracranial part to its confluence with subclavian vein. After performing the Rex recessus to IJV graft anastomosis, the IJV graft proved to be too short for classical end-to-side anastomosis onto the SMV. After clamp testing showing good tolerance of the small bowel, the proximal jejunal branches of the SMV were tied, the proximal SMV was mobilized and transsected 4 cm below the pancreas, and an end-to-end anastomosis between SMV and IJV was performed. Portal pressure decreased from 23 to 13 mm Hg, and intraoperative Ultra Sound Doppler (US Doppler) showed good flows in the shunt. Postoperative course was uneventful, and 1 year after surgery, the child is clinically well, off medication, with a patent shunt, and no portal hypertension. Conclusion This modified MRS technique may be useful when the autologous IJV graft is too short, avoiding the need for prosthetic conduits and prolonged postoperative anticoagulation.

A case of acinar cell carcinoma of the pancreas that formed extensive tumor thrombus of the portal vein.

A 58-year-old man was admitted to our hospital because of anorexia and back pain. He had been previously diagnosed with chronic pancreatitis with blood thrombus of the splenic vein at another hospital. Abdominal ultrasonography and computed tomography revealed a large mass in the body and tail of the pancreas, which directly invaded the stomach and the spleen. Small nodular metastases in both lungs were also detected. Furthermore, tumor thrombus continuously involved the splenic and proximal superior mesenteric vein, main portal vein, and its right intrahepatic branch. A metastatic mass was disclosed in the adjacent liver. The specimens obtained from portal tumor thrombus were histologically compatible with acinar cell carcinoma. Portal tumor thrombus is a rare condition in pancreatic tumors; however, it seems to be important to differentiate tumor thrombus from blood thrombus of the portal vein in order to know the true clinical stage and provide a suitable treatment.

Anatomy of the superior mesenteric vein with special reference to the surgical management of first-order branch involvement at pancreaticoduodenectomy.

To describe our approach to resection of pancreatic head cancers, which involve 1 or both of the first-order branches of the superior mesenteric vein (SMV). In contrast to tumors which involve the proximal SMV, cancers in the inferior aspect of the pancreatic head or root of mesentery (mid gut carcinoid) may involve one of the 2 primary branches of the SMV (the ileal and jejunal branches), with or without involvement of the main trunk of the SMV. Such cases are associated with significant technical challenges. Our surgical approach is described and illustrated. Isolated involvement of the jejunal branch of the SMV may be managed by division of this branch without reconstruction as long as the ileal branch is intact and of good caliber. Tumors which involve the ileal branch of the SMV, in the rare setting in which the jejunal branch is preserved, may also be managed by ligation and resection without reconstruction. Involvement of one of these first-order branches in association with more proximal involvement of the main trunk of the SMV may be successfully managed by ligation of one first-order branch and concurrent segmental resection and reconstruction of the other branch, and the main SMV trunk, with or without an interposition graft. Segmental resection of one of the 2 first-order branches of the SMV may be performed without venous reconstruction if mesenteric venous flow is preserved through the remaining first-order branch. Detailed knowledge of the vascular anatomy of the root of the mesentery is necessary for the performance of complex surgical procedures involving the pancreatic head and root of mesentery.

Effective Hemostasis in Severe Mesenteric Vein Laceration with Tachosil(®), using a Low- or Non-thrombogenic Patch to Prevent Tachosil(®)-induced Thrombosis.

Fibrinogen- and thrombin-coated collagen fleece (FTCC) facilitates surgical hemostasis, and is of particular value during resection of parenchymatous organs. Since thrombosis may ensue if the preparation is unintentionally applied intravascularly, it has not been recommended for treating lacerations of large veins, and no previous reports describe its use in vein repair. Our observations in two patients suggest, however, that FTCC might be indicated for hemostasis in vein injury where vascular suture is difficult or not possible, provided a low- or non-thrombogenic patch is interposed to prevent FTCC-induced vein thrombosis. Our two patients had severe lacerations of the proximal superior mesenteric vein (SMV) not amenable to conventional vein repair. Rapid hemostasis was obtained without suturing using Tachosil(®), an FTCC preparation, covered with omentum. In the first patient hemostasis was obtained at the expense of vein thrombosis, apparently due to contact between the coagulant-containing side of Tachosil(®) and the inside of the vein wall. In our second patient we therefore put a small patch of parietal peritoneum on the section of the Tachosil(®) targeted to cover the vein tear to avoid direct contact between Tachosil(®) and the vein lumen. Ultrasound examination 3 days postoperatively, and autopsy 11.5 months later showed that the vein was widely patent with no stenosis or thrombus. Our observations in these two patients were that an FTCC-omentum pack alone secured rapid hemostasis in severe SMV laceration, and when a peritoneal patch was interposed between FTCC and a lacerated SMV, FTCC-induced vein thrombosis did not occur.

Management of portal vein thrombosis in liver transplantation: influence on morbidity and mortality

Splanchnic thrombosis is a surgical challenge in liver transplantation (LT). The aim of this study was to analyze our experience in the management of portal vein thrombosis, and its influence on evolution. The aim of this study was to analyze our experience in the management of portal vein thrombosis, and its influence on evolution. Between 1999 and 2004, 366 liver transplants were performed in 335 patients. Forty-two patients [12.5%: portal vein thrombosis (PVT) group] had portal thrombosis at the time of LT. We analyzed the technical aspects and compared their evolution with a group of patients without portal thrombosis (n = 293; no-PVT group). Retransplantations were excluded. Of the 42 patients with thrombosis, 18 had partial thrombosis and 16 complete thrombosis [six included the proximal superior mesenteric vein (SMV) and in two the whole splanchnic system]. In 12 cases, usual T-T anastomosis was performed and in 16 cases a thrombectomy was carried out; there were five cases of anastomosis at confluence of the SMV, five cases of anastomosis to a collateral vein, three cases of venous graft, and one case of cavoportal hemitransposition. The operative time was higher in PVT group (417 +/- 103 min vs. 363 +/- 83; p = 0.0005), as RBC transfusion (2.4 +/- 3.1 vs. 1.9 +/- 2.3; p = 0.04), and hospital stay (20.9 +/- 14.9 d vs. 15.1 +/- 10.6; p = 0.002). However, there were no differences in hospital mortality (4% vs. 7.8%; p = 0.98), primary dysfunction (4.8% vs. 7.8%; p = 0.44), or three-yr-actuarial survival (75% vs. 77%; p = 0.95). The incidence of post-transplant thrombosis was higher in the PVT group (15% vs. 2.4%; p = 0.0005). Portal thrombosis is associated with greater operative complexity and rethrombosis, but has no influence on overall morbidity and mortality.

Surgical Management of Chronic Mesenteric Venous Thrombosis

Although mesenteric venous thrombosis is an uncommon disease, it is a diagnostic dilemma and if left untreated results in significant morbidity and mortality. The clinical presentation of mesenteric venous thrombosis (MVT) is varied and depends on the etiology. Prompt recognition and treatment is important as this may limit the progression of thrombosis. Even though medical management is the current mainstay of therapy, there have been reported cases of clinical improvement with operative management. The authors describe an improved outcome following mesenteric-systemic shunting in a symptomatic patient with acute-on-chronic MVT affecting the proximal superior mesenteric vein.

CT of the mesenteric vascular anatomy.

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. 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. 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. 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.

Thrombosis of the portal venous system after splenectomy for pediatric hematologic disease

Splenic, portal, or mesenteric venous thrombosis after splenectomy for hematologic disease has not been reported in the pediatric literature. It is a rare complication associated with significant morbidity and mortality in adult reports. Between 1981 and 1991, 3 patients (13-year-old boy with hereditary elliptocytosis [HE], 13-year-old boy with thalassemia intermedia [TI], and 18-year-old girl with idiopathic thrombocytopenic purpura [ITP]) presented with abdominal pain, nausea, with or without fever, at 4, 11, and 13 days postsplenectomy, respectively. Abdominal Doppler ultrasound (US) and/or computed tomography (CT) showed: (1) an intraluminal filling defect with partial obstruction to flow in the right branch of the portal vein with the remaining vessels patent (HE); (2) splenic vein thrombosis with complete occlusion of the main portal vein and proximal superior mesenteric vein (TI); and (3) complete thrombosis of the splenic vein, proximal superior mesenteric vein and portal vein (including central radicles), with retrogastric collateralization (ITP). Subsequent imaging showed either complete resolution of vascular obstruction on no treatment (patient 1), or portal venous cavernomatous transformation with hepatofugal flow after 6 months of systemic anticoagulation (patients 2 and 3), and all 3 patients are currently asymptomatic. Postoperative sonographic evaluation of a consecutive series of pediatric splenectomies for hematologic disease (n = 16), was performed at a median of 51 days (range, 3 to 124). This demonstrated one case of asymptomatic left portal venous thrombosis with subsequent recanalization in the absence of treatment. Statistical comparison of patients with thrombosis to those without, with respect to age, sex, diagnosis, previous thrombotic episodes, preoperative steroids, preoperative/postoperative platelet count and hemoglobin, operative duration and resuscitation, and splenic mass identified only advanced age and splenic mass as significant predictors of thrombosis ( P < .05). This condition should be realized in the evaluation of every postsplenectomy child with abdominal pain, and consideration should be given to routine postoperative surveillance by Doppler US of patients who have undergone splenectomy for hematologic disease. Patients identified as high risk on the basis of a massively enlarged spleen and advanced age (and perhaps high postoperative platelet count) should be considered for aspirin prophylaxis against thrombosis.

Intestinal infarction secondary to mesenteric venous thrombosis: CT-pathologic correlation.

We reviewed CT of four patients with surgically proved bowel infarction secondary to superior mesenteric vein (SMV) thrombosis. Pathologic correlation was available in all patients. Three patients had thrombus in both portal vein and proximal SMV and the remaining patient had thrombus that was seen only in the peripheral branches of the SMV. Contrast-enhanced CT showed a segmental distribution of marked concentric bowel wall thickening in all four patients. Two patients also showed zones of different attenuation in the bowel wall, which were caused by varying degrees of edema and hemorrhage in the submucosa. Dense peripheral enhancement of the bowel wall was present in one patient. Other CT findings included ascites and mesenteric changes such as edema and vascular engorgement. The combination of thrombus in the SMV with bowel wall thickening strongly suggests bowel infarction and, therefore, warrants initiation of appropriate therapy.

Superior mesenteric vein rotation: a CT sign of midgut malrotation.

Computed tomography (CT) of the pancreas, with its excellent display of peripancreatic anatomy, allows visualization of the major vessels entering the mesenteric root. In scans of the normal upper abdomen obtained at or just below the level of the uncinate process of the pancreas, the proximal superior mesenteric vein (SMV) easily can be identified lying on the right ventral aspect of the superior mesenteric artery (SMA). The authors have observed a characteristic abnormality in this normal vascular arrangement on CT scans of the pancreas in three adult patients with suspected chronic pancreatitis who were subsequently proved to have midgut malrotation. They called this the SMV rotation sign and believe that its detection even on CT scans limited to the level of the pancreas should alert the radiologist to the presence of a midgut malrotation that may have been unsuspected.