CT findings of small bowel strangulation: the importance of contrast enhancement

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.     

Vascular complications in intestinal obstructions. The role of computed tomography

INTRODUCTION: We investigated CT capabilities in showing vascular complications (ischemia, infarction) secondary to intestinal obstruction. SUBJECTS AND METHODS: 32 patients with small bowel obstruction, subdivided in two groups, were examined with CT. The first group consisted of 12 patients with small bowel obstruction complicated by ischemic injury. It was due to loop strangulation in 10 cases and loop distension secondary to colon carcinoma in 2 cases. At surgery the loop strangulation was caused by adhesions in 9 cases and by jejunal hernia in 1 case. Vascular complications were segmentary small bowel infarction in 7 cases, colonic infarction in 2 cases and ischemia, which was resolved after loop debridement, in 3 cases. The second group consisted of 20 patients with intestinal occlusion due to adhesions complicated by a closed loop in 4 cases. All patients were examined with(out) i.v. contrast agent administration. Filling of the intestinal loops by oral contrast agent was never performed. RESULTS: CT identified the vascular injury secondary to intestinal obstruction in 11/12 patients (91%). In one case it was not possible to diagnose mild ischemia, which was found of surgery. CT findings were: loops distention in all the cases; wall thickening in 11 cases with intramural gas in 8 cases and slight contrast enhancement in 1 case; ascites in 2 cases; mesenteric edema in 9 cases; gas at the mesenteric root in 1 case. In the control group, small bowel obstruction was diagnosed with CT in all cases based on the presence of distended loops up to the occlusion site. Parietal alterations above the lesion were never found. CONCLUSION: CT is a sensitive tool for diagnosing small bowel obstruction and for assessing the site and cause of obstruction. CT plays a pivotal diagnostic role in vascular complications, giving very important indications for a correct treatment.     

腹茧症的临床特点及CT诊断(附6例分析)

目的探讨腹茧症的临床特点及CT表现,提高CT对腹茧症的诊断水平。方法回顾性分析6例经手术后病理证实的腹茧症的CT及临床表现。结果腹茧症多以不同形式的肠梗阻为主要症状。CT检查可显示特异性征象:肠管聚集盘曲成团,排列呈外缘光滑的手风琴样或扭麻花样;肠间可见膜状间隔,其周可见茧样纤维膜包裹以及肠梗阻。结论腹茧症的CT表现有一定的特征。结合临床,大多数病例可在术前得到正确的诊断。     

Congenital internal hernia as a cause of small bowel obstruction: CT findings in 11 adult patients

The aim of this study is to report the CT findings in patients proved to have congenital internal hernia (CIH) as a cause of small bowel obstruction (SBO). The CT scans of 11 patients (9 men and 2 women, with ages ranging from 20 years to 95 years (mean 60.7 years), presenting with clinical symptoms and signs of SBO without previous abdominal surgery or trauma, were retrospectively reviewed. In all patients features of SBO were seen. In addition, in nine of them a saclike mass, containing dilated small bowel loops with mesenteric vessels converging toward its orifice was demonstrated and a pre-operative diagnosis of an incarcerated internal hernia was suggested. In the other two, a closed loop obstruction was seen without an identifiable cause. Mural thickening of the entrapped loops within the hernial sac was seen in five patients, with hypoperfusion in four of them, blurring of the mesenteric vessels with localized mesenteric fluid was demonstrated in seven and free peritoneal fluid in 10. All patients were operated on following the CT and an incarcerated CIH was confirmed. Gangrenous bowel was present at exploration in seven cases. One patient died. In conclusion, in patients with intact abdomen and SBO, CT may be the first imaging modality to discover a clinically unsuspected CIH, which requires prompt surgical intervention. Radiologists should be aware of the CT features suggestive of a SBO caused by CIH, i.e. a saclike mass of dilated small bowel loops, as a correct diagnosis will influence patient management and prognosis.     

Active Crohn disease: CT findings and interobserver agreement for enteric phase CT enterography

PURPOSE: To retrospectively evaluate small-bowel enhancement characteristics and the sensitivity, specificity, and interobserver agreement of computed tomographic (CT) findings by using histologic and endoscopic results as a reference standard in patients undergoing enteric phase CT enterography. MATERIALS AND METhods: The institutional review board approved this retrospective HIPAA-compliant study, which included patients who consented to having their medical records used for research purposes. Enteric phase CT enterographic and ileoscopic findings with or without ileal histologic results were examined in 42 patients (24 women, 18 men). Enteric phase CT enterography was performed after 150 mL of intravenous contrast material was administered at 4 mL/sec, with a 45-second delay. Mural attenuation was measured in the distended and collapsed jejunal and ileal loops and in the terminal ileum. Two radiologists examined CT images for findings of Crohn disease. Mural attenuation for different bowel loops was compared by using a Student t test, with kappa statistics used to measure interobserver agreement and Pearson correleation coefficients used to compare visual and quantitative measures. RESULTS: Distended jejunal loops had significantly greater attenuation than distended ileal loops (113 HU vs 72 HU; P < .001). Attenuation of collapsed jejunal (134 HU) and ileal (108 HU) loops was greater than that of distended jejunal and ileal loops (P < .001). Terminal ileal enhancement was the most sensitive visual CT finding of Crohn disease for both radiologists. Mural thickening demonstrated the greatest interobserver agreement (kappa = 0.83). Visual enhancement and quantitative mural attenuation were significantly correlated (P < .003). CONCLUSION: At enteric phase CT enterography, jejunal attenuation is greater than ileal attenuation and collapsed bowel loops demonstrate greater attenuation than distended bowel loops. Mural hyperenhancement and increased mural thickness are the most sensitive CT findings of active Crohn disease.     

Internal hernia: clinical and imaging findings in 17 patients with emphasis on CT criteria

PURPOSE: To review the clinical and radiologic features of internal hernia and to derive useful radiographic and CT criteria to assist in diagnosis. MATERIALS AND METHODS: Retrospective review of medical records revealed 17 patients with surgically proved internal hernia (three paraduodenal, 14 transmesenteric) who had 15 computed tomographic (CT) scans and three small-bowel follow-through (SBFT) images. RESULTS: CT signs common to all types of internal hernia included evidence of small-bowel obstruction; clustering of small bowel; stretched, displaced, crowded, and engorged mesenteric vessels; and displacement of other bowel segments, especially the transverse colon and fourth portion of the duodenum. Left-sided paraduodenal hernias demonstrated a sac-like mass of small-bowel loops interposed between the stomach and pancreatic tail and a posterior mass effect on the stomach. All three paraduodenal hernias were diagnosed confidently at retrospective review of CT and SBFT findings. Transmesenteric hernias demonstrated clustered small-bowel loops adjacent to the abdominal wall without overlying omental fat and central displacement of colon and were frequently complicated by small-bowel volvulus (five of 14) and bowel ischemia (six of 14). CT demonstrated signs of volvulus in four of six patients with ischemia. CT findings considered definitive or suggestive of internal hernia were demonstrated in 15 patients. CONCLUSION: Internal hernia is an important and underdiagnosed condition. Transmesenteric hernia is most common in our experience and is usually related to prior abdominal surgery, especially with creation of a Roux-en-Y anastomosis. CT may allow confident diagnosis in most patients.     

Small bowel obstruction due to incarcerated sciatic hernia: ultrasound diagnosis

A 71-year-old woman presented with vomiting, abdominal pain and vague right gluteal discomfort. Abdominal ultrasound showed ascites and dilated small bowel loops with peristaltic movement, while transgluteal ultrasound revealed entrapped ascites beneath gluteal muscles and an oedematous, immobile bowel loop trapped between the sacrum and iliac bone with barely visible colour Doppler flow suggestive of an incarcerated sciatic hernia. CT demonstrated similar findings and subsequent surgery confirmed the diagnosis. To our knowledge, this is the first report of a pre-operative diagnosis of incarcerated sciatic hernia on ultrasound.     

腹股沟及其周围疝所致肠梗阻CT诊断

目的 探讨CT对腹股沟及其周围疝所致肠梗阻的诊断价值.资料与方法 回顾性分析17例经手术证实的腹股沟及其周围疝所致肠梗阻的CT表现,CT检查包括全腹部平扫、动脉期及门脉期增强.结果 17例患者均有不同程度的肠梗阻表现,腹股沟斜疝9例,CT表现为疝囊内肠管从腹壁下动脉外侧、腹股沟韧带前上方走行,行经腹股沟管内;直疝1例,CT表现为扩张的小肠肠管从腹壁下动脉内侧的直疝三角区(Hesselback三角)直接由后向前突出,疝囊不进入阴囊;股疝3例,CT表现为股疝疝囊位于股三角区、耻骨结节水平线以后、腹股沟韧带后下方;闭孔疝4例,CT表现为闭孔外肌与耻骨肌之间的肠管影和腹部肠管相连.结论 CT检查能明确诊断腹股沟及其周围疝所致肠梗阻.     

Primary ileal volvulus in neonates: radiologic findings in two cases

Two cases of primary small bowel volvulus in neonates are presented. On abdominal plain radiographs pseudotumor sign was seen in both cases. CT showed intensely distended fluid-filled small bowel loops on the right side of the abdomen and diffuse distention of the proximal small bowel loops with air-fluid levels. US also showed distended fluid-filled loops containing echogenic foci without peristalsis. We consider that CT and US can play important roles in the diagnosis of small bowel volvulus in neonates.     

肠旋转不良伴中肠扭转的CT诊断

目的：研究CT对肠旋转不良伴中肠扭转（volvuhus in intestinal malrotation,VIM)的诊断价值。方法：回顾性分析6例手术证实的VDIM的CT表现。男5例,女1例,年龄7～25岁,平均13岁。结果：6例均表现为肠系膜根部类团块影,其中4例见典型“漩涡征”,2例呈类“靶征”,但增强扫描亦出现“漩涡征”。毗邻部肠袢扩张,肠系膜静脉不同程度淤积扩张,2例伴受累系膜、肠壁重度水肿。6例均见系膜根部肠系膜上动脉（superior mesenteric artery,SMA）、肠系膜上静脉（superior mesenteric vein,SMV)血管正常排列迷失。结论：“漩涡征”伴系膜根部SMA、SMV正常排列迷失为本病的特征性CT表现。     

螺旋CT及重组技术对小肠Crohn病的诊断价值

目的：探讨小肠Crohn病的CT表现。方法：回顾性分析经病理证实的8例Crohn病的CT扫描及后处理图像,分析病变肠管的数量、部位、肠壁的厚度和增强后病变肠壁的强化及并发症（蜂窝组织炎、炎性肿块、脓肿和瘘管）。结果：CT及后处理图像均能显示小肠Crohn病的病变肠段,敏感度为100%,8例共显示27段炎症肠壁。小肠Crohn病的CT表现：增强后所有病变肠段肠壁均有强化,25个病变肠段（92%）肠壁增厚,病变累及第6组小肠（回肠远段）8例,累及第5组（回肠中段）、第4组（回肠近段）、第3组（空肠远段）和第2组小肠（空肠近段）者分别7例、3例、2例和2例,累及回盲部3例,广泛累及结肠2例,8例均同时累及2组及2组以上小肠并呈节段性分布。肠系膜血管改变5例（62%）,肠管周围蜂窝织炎3例,炎性肿块2例,腹腔脓肿形成1例,未见瘘管形成。结论：螺旋CT及后处理技术是诊断小肠Crohn病的一种敏感的检查方法,并可判断病变的活动性,对指导临床治疗具有重要意义。     

小肠梗阻CT表现对手术治疗的预测价值

目的：探讨小肠梗阻(SBO)CT 表现对手术治疗的预测价值。方法70例 SBO 患者按照治愈方式分为非手术治疗组与手术治疗组,回顾性比较2组间 CT 表现有无差异,分析有意义 CT 表现对于手术治疗的预测价值。结果70例 SBO 中,33例采用非手术治疗,37例采用手术治疗。移行带肠壁完全瘪陷、肠系膜水肿、腹水、肠系膜静脉淤血增粗、肠壁强化减低、肠系膜动脉和静脉强化减低出现的几率在手术治疗组显著高于非手术治疗组(P <0.05),预测手术的比数比分别为10.56、5.13、4.72、5.45、5.77、3.02、6.59。而扩张肠管内径、肠壁厚度、环靶征、肠壁积气、肠系膜血管移位、聚集和扭曲出现的几率在2组间无统计学差异。结论SBO 多种 CT 表现对其手术治疗具有预测价值,可为 SBO 的治疗提供重要信息。     

A spontaneous strangulated transomental hernia: Prospective and retrospec-tive multi-detector computed tomography findings Camera L,De Gennaro A,Longobardi M,Masone S,Calabrese E,Del Vecchio W,Persico G,Salvatore M简

Transomental hernias are among the rarest type of all internal hernias which overall account for less than 6% of small bowel obstructions. Most transomental hernias occurring in adults are either iatrogenic or post-traumatic. More rarely, a spontaneous herniation of small bowel loops may result from senile atrophy of the omentum. We report a case of an 86-year-old male who presented with signs and symptoms of small bowel obstruction but had no past surgical or traumatic abdominal history. At contrast-enhanced multi-detector row computed tomography (CT), a cluster of fluid-filled dilated small bowel loops could be appreciated in the left flank, with associated signs of bowel wall ischemia. Swirling of the mesenteric vessels could also be appreciated and CT findings were prospectively considered consistent with a strangulated small bowel volvulus. At laparotomy, no derotation had to be performed but up to 100 cm of gangrenous small bowel loops had to be resected because of a transomental hernia through a small defect in the left part of the greater omentum. Retrospective reading of CT images was performed and findings suggestive of transomental herniation could then be appreciated.     

粘连性腹内疝及其合并肠缺血坏死的MSCT诊断

目的 探讨粘连性腹内疝及合并绞窄性肠坏死的MSCT特征.方法 回顾性分析21例经手术证实的粘连性腹内疝的CT资料,CT原始数据经多平面重建(MPR)及CT血管造影(CTA),以显示疝环、疝入肠系膜、疝内肠管的特征.结果 19例粘连性腹内疝均显示疝环,小肠扩张积液、聚集并移位,其中17例显示疝环处肠管狭窄与扩张肠管移行;17例显示疝入肠系膜水肿、增厚,肠系膜血管纠集、充血,其中11例显示疝环处肠管及其系膜扭转;15例显示腹水.根据疝入肠管影像表现将粘连性腹内疝分型:Ⅰ型为肠管扩张伴肠壁增厚(7例);Ⅱ型为肠管扩张不伴肠壁增厚(9例);Ⅲ型为肠管不扩张但肠壁增厚(5例).3型腹内疝肠管壁平扫CT值、动脉及门脉期肠壁强化值差异有统计学意义(P<0.05),Ⅰ和Ⅲ型小于Ⅱ型,Ⅰ、Ⅲ型之间的差异无统计学意义(P>0.05).8例粘连性腹内疝合并绞窄性肠坏死(5例为Ⅰ型,3例为Ⅲ型),CT显示肠扭转伴疝入小肠壁显著水肿增厚,肠壁模糊呈持续性低强化,其中4例显示肠系膜上静脉血栓栓塞,3例显示肠系膜上动脉主干或分支闭塞,8例均显示大量腹水.结论 粘连带形成的疝环,狭窄与扩张肠管移行以及小肠扩张、聚集并移位提示粘连性腹内疝的存在;疝入肠系膜水肿,血管纠集,充血,肠系膜血管闭塞,肠管壁显著水肿增厚并持续低强化,则是绞窄性肠坏死的影像特征.     

隐匿性外伤性肠破裂的CT诊断

目的 探讨隐匿性外伤性肠破裂的CT表现,以提高对该病的诊断水平.方法 对11例手术证实的隐匿性外伤性肠破裂CT表现进行回顾性分析.结果 主要特异性CT征象有:(1)游离气体,共4例,位于外伤处小肠周围、膈下、腹膜后间隙,或位于包块内各l例;(2)肠间隙血肿或肌壁间高密度血肿(4例);(3)肠壁损伤征,受累肠肇局部低密度影,增强扫描强化局限性减弱,相邻肠管强化相对增强(3例);(4)外伤处小肠及周围包块(4例),增强扫描该包块有明显环形强化,延迟扫描有进一步强化.其他征象有:(1)腹腔及肠间隙积液(5例),周围脂肪间隙或肠间隙模糊改变(8例);(2)肠梗阻(11例).结论 CT对诊断隐匿性外伤性肠破裂钉重要诊断价值.     

CT findings in patients with small bowel obstruction due to phytobezoar

The role of CT in evaluating patients with small bowel obstruction (SBO) has been extensively described in the current literature. We present the CT findings of SBO due to a phytobezoar, afterwards surgically confirmed, in 5 men and 1 woman (aged 32–89 years) out of 95 patients diagnosed by CT as having SBO in a 44-month period. These six patients underwent abdominal CT prior to operation and the CT findings were retrospectively reviewed. All six patients presented with clinical symptoms and signs of SBO; three of them had undergone gastric surgery 13, 17, and 22 years earlier, respectively. In all six cases, CT showed an ovoid intraluminal mass, 3×5 cm in size and of a mottled appearance, at the transition zone between dilated and collapsed small bowel loops. This was in contrast to feces-like material (the small bowel feces sign), seen within dilated small bowel loops in nine patients with SBO, and was typically longer. As CT is frequently performed for suspected SBO, an ovoid, short intraluminal mottled mass seen at the site of an obstruction may be regarded as a pathognomonic preoperative sign of an obstructing phytobezoar.     

Small bowel obstruction from adhesions: which CT severity criteria to research?

PURPOSE: To determine the value of known computed tomographic (CT) criteria to differentiate non-complicated from complicated (strangulation, necrosis) small bowel obstruction. MATERIALS AND METHODS: 43 patients with a definitive diagnosis of small bowel obstruction based on clinical, sonographic, CT, surgical and pathological findings were included. All patients had small bowel obstruction caused by adhesions confirmed at surgery. The obstruction was non-complicated in 28 patients and complicated in 15 patients. The CT examinations from all patients were retrospectively reviewed by three experienced radiologists using a set of pre-defined criteria. Attention was focused on the following signs: reduced enhancement of the small bowel wall, mural thickening, congestion of small mesenteric veins, and ascites. Results were correlated with surgical and/or pathological data. RESULTS: For the diagnosis of complicated obstruction, reduced bowel wall enhancement had a sensitivity of 57% and a specificity of 100%, a bowel wall thickness greater than 3 mm had a sensitivity of 35% and a specificity of 100% and a bowel wall thickness less than 1 mm had a sensitivity of 35% and a specificity of 93%. Ascites and congestion of small mesenteric veins were not significant. The multivariate analysis showed that the association of bowel-wall thickening and reduced enhancement of the small bowel wall was significant (sensitivity of 71%, specificity 100%, and accuracy 90%). CONCLUSION: Among the CT criteria used to diagnose complications from small-bowel obstruction that were evaluated in this study, only three were significant with a high specificity but low sensitivity.     

Traumatic hypovolemic shock revisited: the spectrum of contrast-enhanced abdominal computed tomography findings and clinical implications for its management

Hypovolemic shock is often seen in patients with severe blunt trauma who have suffered from blood circulation inadequate to maintain oxygen delivery to multiple organs. The early recognition and prompt management of hypovolemic shock in patients with multiple injuries are mandatory to improving prognosis and patient conditions. The diagnostic accuracy of computed tomography (CT) as a primary diagnostic tool is well established. The abdominal organs show several common and classic appearances on contrast-enhanced CT in patients with trauma. The hypovolemic shock complex is reported in the previous literature as decreased enhancement of the viscera, increased mucosal enhancement and luminal dilation of the small bowel, mural thickening and fluid-filled loops of the small bowel, the halo sign and flattening of the inferior vena cava, reduced aortic diameter, and peripancreatic edema. However, there have been controversial CT reports with contradictory appearances. Physicians understanding these findings could prompt alternative approaches to the early assessment and management of hypovolemic shock. The aim of this article is to illustrate common and well-known abdominal CT features in patients with traumatic hypovolemic shock, to discuss controversial CT signs in the pancreas and adrenal gland, and to describe CT findings’ clinical implications when managing hypovolemic shock.     

CT scanning in patients with opsomyoclonus: importance of nonenhanced scan

Children with neuroblastoma presenting with opsomyoclonus are a diagnostic dilemma; they may not have a palpable mass or elevated urine catecholamines and the neurologic manifestation often precedes the discovery of a primary tumor by several months. The delay in diagnosis probably reflects the difficulty in detecting small lesions. Even with high-resolution computed tomography (CT), difficulty was recently experienced in identifying small retroperitoneal lesions in three patients who presented with opsomyoclonus. Calcifications in these small neoplasms resembled contrast material within adjacent small-bowel loops that were not discernible until additional, unenhanced scans were obtained. It is recommended that the initial CT evaluation in patients presenting with opsomyoclonus be performed without bowel or intravenous contrast enhancement.     

The relevance of free fluid between intestinal loops detected by sonography in the clinical assessment of small bowel obstruction in adults

INTRODUCTION: The main role of the radiologist in the management of patients with suspicion of small bowel obstruction is to help triage patients into those that need immediate surgical intervention from those that require medical therapy or delayed surgery. Ultrasound examination is usually considered not helpful in bowel obstruction because of air in the intestinal lumen that interferes the evaluation of the intestinal loops, however recently some Authors attested the increasing important role of sonography in the acute abdominal disease. Aim of our report is to demonstrate the value of free fluid detected by US in differentiating between low and high-grade small bowel obstruction. MATERIALS AND METHODS: The study is based on 742 consecutive patients who presented symptoms of the acute abdomen; all patients had undergone initial serial abdominal plain film and US examinations prior to any medical intervention. We reviewed the imaging findings of 150 cases in whom small bowel obstruction was clinically suspected and confirmed at surgery. We consider the following radiographic and US findings: dilatation of small bowel loops; bowel wall thickness; presence of air-fluid levels; thickness of valvulae conniventes; evidence of peristalsis; presence and echogenicity of extraluminal fluid. We looked at the value of extraluminal peritoneal fluid at US examination in differentiating low and high-grade small bowel obstruction based on the surgical outcome. RESULTS: In 46 patients altered peristaltic activity, thin bowel walls, fluid filled loops with hyperechoic spots in the bowel segment proximal to obstruction were noted at US, whereas radiographic features were: moderate dilatation of small bowel loops, with thin bowel wall and evidence of numerous and subtle valvulae conniventes; presence of air-fluid levels was also noted. In 70 other patients, US examination revealed all the findings described in the precedent cases and also the presence of free extraluminal fluid; abdominal plain film showed an increased dilatation of small bowel loops with moderate thickened wall and air-fluid levels. In 34 other patients US examination revealed the presence of thick-walled loops, hypoperistalsis and a larger amount of free extraluminal fluid. Radiographic findings in these patients were: horizontal featured and markedly dilated small bowel loops presenting parietal thickness, presence of intraluminal fluid stasis and evidence of thickened, sparse and incomplete valvulae conniventes. At surgery etiology of small bowel obstructions was various, but most of cases related to adhesions (70 cases). The presence of extraluminal fluid were confirmed at surgery in 104 patients. CONCLUSIONS: Our experience using sonography in suspicion of SBO (small bowel obstruction) suggests the usefulness of this imaging modality to differentiate a functional or obstructive ileus, demonstrating the evidence of intestinal peristalsis. Furthermore, the presence of a large amount of fluid between dilated small bowel loops suggests worsening mechanical small bowel obstruction, that requires not a medical therapy but immediate surgery.