Congenital mesenteric aneurysm and mesenteric arterioportal fistula

A unique case with superior mesenteric artery aneurysm and arterioportal fistula resulting from mesenteric arteriovenous malformation is presented, and the relevant literature is reviewed. Received: 16 December 1994/Accepted after revision: 31 March 1995     

Chronic mesenteric ischemia: stenting of mesenteric arteries

This article focuses on stent placement in mesenteric arteries in patients with the rare diagnosis of chronic mesenteric ischemia. We present a survey from the initial stage of recognition of this gastrointestinal disorder and its manifestations to treatment by stenting to avoid further ischemic episodes and bowel infarction and necrosis. The advantages of stent placement in splanchnic arteries are discussed in comparison to open surgical revascularization.     

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     

Isolated dissection of the superior mesenteric artery

Dissection of the superior mesenteric artery (SMA) not associated with aortic dissection is rare. The purpose of this study is to describe the computed tomographic (CT) findings of this condition. We studied the CT findings of six patients with isolated dissection of the SMA. CT demonstrated thrombosis of the false lumen or intramural hematoma (n = 4) and/or intimal flap (n = 4) in all six patients. Other CT findings were enlarged diameter of the SMA (n = 5), increased attenuation of the fat around the SMA (n = 5), and hematoma in the mesentery with hemorrhagic ascites (n = 1). CT is useful for the diagnosis of isolated dissection of the SMA, and increased attenuation of the fat around the artery is considered the key to the diagnosis when no definite findings are evident.     

Familial fibromuscular dysplasia of the mesenteric arteries

We have reported the case of a critically ill 17-year-old girl who had an evolving gastrointestinal infarction when she came to our institution 11 months before she died. After surgical revascularization, biopsy of the superior mesenteric artery showed FMD. We interviewed and examined all close consanguineous relatives and found abdominal bruits in the patient's younger sister and mother. Arteriograms showed total occlusion of the celiac and superior mesenteric arteries in the sister, and a subtotal celiac occlusion in the mother. Postprandial abdominal pain and constipation in the sister prompted elective mesenteric revascularization, and biopsy of the superior mesenteric artery confirmed FMD identical to that of her older sister. The mother, who is asymptomatic, has single vessel disease and has not required operative intervention. Our report strongly supports the hypothesis of a genetic basis for this arteriopathy.     

Color Duplex evaluation of the mesenteric artery

Ischemic colitis is the most common form of intestinal ischemia. Diagnosis is made at clinical examination and endoscopy and completed by vascular imaging, but color Doppler US may become a first-line imaging technique for the evaluation of the mesenteric circulation.We present the case of an 80-year-old woman hospitalized for recurrent ischemic colitis of the sigmoid. At a previous hospitalization, color Doppler US examination showed medium to severe stenosis at the origin of the inferior mesenteric artery. However, CT angiography was negative and the condition was therefore misdiagnosed. Eight months later the patient was admitted again with abdominal pain and rectal hemorrhage. Rectosigmoidoscopy documented the presence of ischemia of the sigmoid mucosa. Angiography showed the presence of severe stenosis at the origin of the inferior mesenteric artery so revascularization was carried out by percutaneous transluminal angioplasty (PTA) during the same session. Follow-up showed normal patency of the inferior mesenteric artery after revascularization, and subsequent endoscopic evaluation documented gradual colonic mucosal ischemia resolution. Blood flow at the level of the inferior mesenteric artery was assessed using color Doppler US. The presented case confirms that color Doppler US is a valid first-line imaging technique in the assessment of ischemic intestinal lesions. It is reliable in the evaluation of the mesenteric arterial circulation, and it also allows assessment of blood flow alterations caused by stenosis and identification of localized hemodynamic stenosis which may be missed at CT-angiography or MR-angiography. Arteriography remains the examination of choice in case of discrepancy between first-and second-line imaging techniques and in all cases which offer the possibility of endovascular revascularization.     

Recurrent retroperitoneal mesenteric cyst

A mesenteric cyst is an uncommon cause of a palpable abdominal mass. A correct preoperative diagnosis can be made by the combined use of radiographic and sonographic examinations in conjunction with the clinical features. A patient with a retroperitoneal cyst extending into the leaves of the mesentery is presented. The cyst recurred 4 years after surgery.     

Intravenous iloprost increases mesenteric blood flow in experimental acute nonocclusive mesenteric ischemia

OBJECTIVE: To evaluate the effect of an intravenously administered synthetic epoprostenol analog, iloprost, in nonocclusive acute mesenteric ischemia induced by cardiac tamponade. DESIGN: Prospective, randomized, controlled experimental study. SETTING: Animal research laboratory at a university medical center. SUBJECTS: Ten Yorkshire pigs (weight range, 20-25 kg). INTERVENTIONS: Nonocclusive acute mesenteric ischemia was induced by pericardial tamponade. Pigs were randomized to receive either a low-dose, continuous intravenous infusion of iloprost (0.075 microg/kg/min) or an equivalent volume of normal saline to serve as the control. Infusion of iloprost or saline was continued after pericardial tamponade was reversed. METHODS: Ten anesthetized and ventilated pigs underwent laparotomy and thoracotomy. A pulmonary artery catheter was inserted, a magnetic flow probe was positioned around the superior mesenteric artery (SMA), and cannulation of the pericardial space was performed. Pericardial tamponade was induced by injecting 5% dextrose in water into the pericardial space until blood flow in the superior mesenteric artery decreased to half of baseline. After 60 mins, animals received either a continuous intravenous infusion of iloprost at 0.075 microg/kg/min (n = 6) or an equal volume of normal saline (n = 4) for 60 mins. Pericardial fluid was then removed, and iloprost or normal saline infusion was continued for another 60 mins. MEASUREMENTS: Heart rate, blood pressure, cardiac output, oxygen delivery, oxygen consumption, SMA blood flow, ileal Pco2, ileal intramucosal pH, and serum lactate levels of mixed venous blood and mesenteric venous blood were recorded at baseline, after pericardial tamponade was induced, during the iloprost or normal saline infusion with pericardial tamponade, and after removal of pericardial fluid (reperfusion period). RESULTS: Iloprost infusion increased SMA blood flow by 60% in this model of nonocclusive mesenteric ischemia (from 168 +/- 41 to 269 +/- 76 mL/min; p <.05). The effect of iloprost infusion was more prominent after the tamponade (422 +/- 87 mL/min in the iloprost group vs. 232 +/- 111 mL/min in the control group; p <.05). Increased mesenteric perfusion decreased intestinal mucosal hypercarbia, leading to improvement of intramucosal pH.     

Intra-abdominal mesenteric desmoid tumor

We have presented a case of mesenteric desmoid tumor, with analysis of 21 such cases previously reported in Japan.     

Sympathetic discharge to mesenteric organs and the liver. Evidence for substantial mesenteric organ norepinephrine spillover.

This study using sampling of blood from the portal vein, in addition to arterial and hepatic sites, to estimate separately spillovers of norepinephrine from mesenteric organs and the liver in seven patients undergoing upper abdominal surgery. Conventional measurements in arterial and hepatic venous plasma provided a measure of net hepatomesenteric NE spillover (403 pmol/ml) that indicated a 13% contribution of these organs to total body spillover of NE into systemic plasma (3,071+/-518 pmol/min). The net hepatomesenteric spillover of NE into systemic plasma was much lower than the spillover of NE from mesenteric organs into portal venous plasma (1,684+/-418 pmol/min). This and the hepatic spillover of NE into systemic plasma (212+/-72 pmol/min) indicated a considerable combined spillover of NE from hepatomesenteric organs (1,896+/-455 pmol/min). The sum of the latter estimate with the difference between total body and net hepatomesenteric NE spillovers provided an adjusted total body spillover of NE into both systemic and portal venous plasma (4,564+/-902 pmol/min). Mesenteric organs made a 37% contribution, and the liver made a 5% contribution to the adjusted total body spillover of NE. Thus, a substantial proportion of total body sympathetic outflow is directed towards mesenteric organs; this is obscured by efficient hepatic extraction of NE (86+/-6%) when measurements are restricted to arterial and hepatic venous plasma.     

Evaluation of acute mesenteric ischemia: accuracy of biphasic mesenteric multi-detector CT angiography

The purpose of this study was to explore the accuracy of multi-detector row helical CT (MDCT), using a biphasic mesenteric angiography protocol for evaluation of acute mesenteric ischemia (AMI). In total, 79 consecutive patients with clinical signs of AMI underwent contrast enhanced 16- or 40-channel MDCT. MDCT findings were correlated with surgery, endoscopy and clinical outcome. Sensitivity, specificity, and positive and negative predictive values were calculated using the patients in which AMI had been excluded as a control group. In 28 patients the final diagnosis was AMI. In 27 patients (96.4%) MDCT correctly diagnosed AMI (specificity of 97.9%). A sensitivity of 93%, specificity of 100%, and positive and negative predictive values of 100% and 94%, respectively were achieved for the CT findings of visceral artery occlusion, intestinal pneumatosis, portomesenteric venous gas or bowel wall thickening in combination with either portomesenteric thrombosis or solid organ infarction. Our findings suggest that mesenteric MDCT angiography is an accurate tool for fast diagnostic work-up of patients with suspected AMI.     

肠系膜间质瘤的CT诊断价值

目的：探讨肠系膜间质瘤的CT表现。方法：回顾性分析经手术病理证实的13例来源于肠系膜的间质瘤的CT表现特点。结果：肿块位于小肠系膜7例,结肠系膜6例。分叶状6例,不规则形3例,圆形或类圆形4例。瘤体最大直径为2．5-18．4cm,平均约为（10．5±4．9）cm。肿块密度均匀5例;肿块内坏死8例,肿块内液气平面2例。增强后肿瘤均呈不均匀轻度一明显强化,肿瘤坏死、囊变、含气无明显强化。按照肿瘤实性部分强化方式分为：Ⅰ型：静脉期下降型（8例）,动脉期轻度一明显均匀或不均匀强化,动脉期病灶内可见增粗、增多的肿瘤血管强化,而静脉期强度程度下降,低于动脉期。Ⅱ型：静脉期升高型（5例）,动脉期轻度一明显均匀或不均匀强化,静脉期强化程度持续增加,高于动脉期,呈渐进性强化特点。3例出现瘤体邻近肠系膜淋巴结肿大。结论：肠系膜间质瘤CT表现具有一定特征性,CT检查对该疾病的诊断及鉴别诊断有重要价值。     

Ultrasonic evaluation of the superior mesenteric artery.

With the use of gray scale B scan ultrasound, it is now feasible in many cases to detect portions of the superior mesenteric artery (SMA) arising from the aorta. Thus, it is possible to measure the aortomesenteric angle and distance. We evaluated a series of patients by ultrasound to determine the normal values for the SMA angle, distance, and lumen diameter. Patients were also examined who had pathological conditions that might produce an alteration in the angle and distance. Abnormal widening was observed in patients with aortic aneurysms and para-aortic lymphosarcomatous nodes. In patients suspected of having duodenal ileus, there was evidence of narrowing of the superior mesenteric artery angle and distance. However, a comparable group of asymptomatic patients of the same age showed a similarly narrowed angle and distance. It was thus concluded that the narrowing of the aortomesenteric angle and distance is not a cause of duodenal ileus. Knowledge of the SMA and aortic lumen diameter has been helpful in selecting the proper catheter and approach for selective arteriography.