CT of small bowel obstruction in adults

The increasing use of computed tomography in evaluating patients with acute abdominal pain has revolutionized the diagnosis of small bowel obstruction in adults. Computed tomography is incontestably the most useful and powerful tool to make positive, topographic, and etiologic diagnoses of small bowel obstruction. Good knowledge of some key signs and rigorous analysis of computed tomographic images by radiologists should lead to improved diagnosis and appropriate treatment.     

CT findings of isolated small bowel angioedema due to iodinated radiographic contrast medium reaction

We report three cases of small bowel angioedema that showed circumferential wall thickening of the small bowel loops during infusion of iodinated contrast media. Follow-up small bowel series or computed tomography confirmed the normalized small bowel loops. When significant wall thickening of the long segment of the small bowel during infusion of contrast media is seen, radiologists should consider the possibility of isolated small bowel angioedema in spite of its rarity. Received: 4 February 1998/Accepted: 11 March 1998     

Helical CT of the small bowel with an alternative oral contrast material in patients with Crohn disease

Background: We assessed the usefulness of helical computed tomography (CT) with a negative oral contrast material for detecting Crohn disease. Methods: Thirty-eight patients with proven Crohn disease were examined. We administered a large volume of a new negative oral contrast material (Mucofalk suspended in water) and then proceeded with helical CT scanning. This technique is an alternative to CT and conventional enteroclyses that use a nasojejunal tube. Two radiologists interpreted the scans, and patients were interviewed about their tolerance of the procedure. We created multiplanar reformatted images in all cases. Potential of small bowel distention by Mucofalk was evaluated by two observers on a three-point scale, and interobserver agreement was calculated with κ statistics. Results: All patients who underwent enteroclysis stated that CT was the more comfortable method, the taste of the peroral contrast medium was considered good by 52.6% and acceptable by 47.4%. Small bowel distention was excellent in 55% of cases, moderate in 26%, and poor in 19%, with an interoberserver agreement of 78%. CT findings correlated with enteroclysis in 27 patients who underwent both methods. Analysis of CT versus enteroclysis showed a sensitivity of 89% for CT versus 78% for small bowel enteroclysis. Conclusion: Mucofalk CT is a simple, rapid, noninvasive, and accurate method of evaluating extramucosal manifestations of Crohn disease. The tubeless procedure improved patients' comfort and decreased time, cost, and radiation exposure.     

Acute diverticulitis of the small bowel: CT findings

We present the computed tomographic (CT) findings in two cases of small bowel diverticulitis, one affecting the jejunum and the other a Meckel's diverticulum. The main CT finding was that of a mass with an air–fluid collection in contiguity with small bowel loops. Received: 18 September 1998/Accepted: 2 December 1998     

Hyperattenuating insulinoma at unenhanced CT

We report a case with insulinoma that showed higher attenuation than normal pancreatic parenchyma on precontrast CT. Pathology of the surgical specimen revealed the presence of psammoma bodies, which were responsible for hyperattenuation. It is worthwhile to obtain precontrast CT in patients suspected of having insulinoma. Received: 22 December 1994/Accepted: 4 February 1995     

Complications after laparoscopic gynecologic procedures: CT findings

Laparoscopic gynecologic surgery has gained worldwide popularity in the past few years, but complications of this new technique do occur. We encountered three patients who developed major complications after laparoscopic gynecologic procedures including perforation of the sigmoid colon, urinary bladder, and ureter. We report the computed tomographic findings of these cases and the diagnostic dilemmas they posed. Received: 9 November 1999/Accepted: 15 December 1999     

CT evaluation of the resectability of gastric cancer postchemotherapy

Background: To determine the accuracy of CT in the postchemotherapy assessment of resectability of gastric cancer. Methods: Thirty patients deemed to have unresectable gastric cancer on CT were studied. This was verified at laparotomy in 10 of these patients. Following initial assessment, all received three to eight cycles of chemotherapy aiming for disease control and potential resection. Serial CT examinations, endoscopy, and biopsy were performed after the fourth, sixth, and eighth cycle of treatment. The primary tumor and lymph nodes seen on CT were compared with operative findings. Results: After completion of chemotherapy, CT findings were correct in 23 patients. Fourteen of them had operable tumors and nine were inoperable. However, the CT findings were either equivocal or incorrect in the remaining seven patients. Conclusion: Chemotherapy is now able to downstage a previously inoperable gastric cancer, and CT is an accurate method in identifying those patients who can proceed to resection. Received: 24 October 1994/Accepted after revision: 6 April 1995     

Lymphoepithelial cysts of the pancreas: CT and sonographic findings

Two cases of rare lymphoepithelial cyst (LEC) of the pancreas are presented. Although the histogenesis of this lesion is not known, it can be histologically differentiated from other pancreatic and retropancreatic cysts. The importance of its recognition is in the distinction from cystic neoplasm of the pancreas. Received: 24 October 1996/Accepted: 27 November 1996     

Proximal small bowel intussusceptions in adults: CT appearance and clinical significance

Background: According to the clinical literature, intestinal intussusception in adults is rare, is associated with a pathologic lead point, and is usually treated surgically. Nonobstructing small bowel intussusception has been reported as a transient finding on computed tomographic (CT) studies.Methods: We evaluated the radiographic and clinical findings in 24 patients who were found to have 26 proximal small bowel intussusceptions on abdominal CT scans performed for a variety of indications.Results: Twenty patients with intussusceptions had no evidence of small bowel obstruction. The transient and clinically insignificant nature of 22 intussusceptions in these 20 patients was proven radiologically (n = 14), surgically (n = 1), or by clinical follow-up (n = 7). These patients demonstrated a bowel-within-bowel pattern on multiple contiguous images and absence of strangulation or intestinal dilatation. No lead points were demonstrated in these patients. Three other patients had symptoms of low-grade small bowel obstruction and were treated conservatively. Extensive follow-up investigations showed no recurrence of intussusception or a lead point. One patient had high-grade obstructive intussusception with intestinal ischemia and required surgical resection of necrotic bowel.Conclusions: Proximal small bowel intussusceptions are likely to be transient and nonobstructive and unlikely to have a significant lead point.     

CT appearance of direct leukemic invasion of bowel

Although leukemic invasion of bowel is frequently seen on pathologic examination, it has rarely been described in the imaging literature. Previous radiographic reports have relied mostly on non-cross-sectional imaging techniques such as barium enema and have detected abnormalities only in the most advanced stages of disease when prognosis is uniformly poor. We describe a case of direct leukemic invasion seen on computed tomography which may offer the advantage of earlier detection and more favorable prognosis. Received: 25 March 1996/Accepted: 24 April 1996     

Renal and perirenal space involvement in acute pancreatitis: spiral CT findings

Background: This study was conducted to estimate the prevalence and morphologic computed tomographic (CT) features of renal and perirenal space abnormalities in acute pancreatitis in correlation with the severity of pancreatitis. Methods: One hundred fifty-nine contrast-enhanced CT scans of 100 consecutive patients with acute pancreatitis were retrospectively and independently reviewed by three observers. All CT images were obtained using contrast-enhanced helical CT (collimation width = 5 mm, table increment = 7 mm/s, reconstruction interval = 5 mm, scan delay time = 30–50 s). Additional maximized images (field of view = 260 mm) of the perirenal space were available for review. All CT scans were scored with the CT Severity Score Index: pancreatitis was graded as mild (0–2 points), moderate (3–6 points), and severe (7–10 points). Interobserver agreement for both the severity score and the presence of renal and perirenal involvement was calculated. Correlation between the prevalence of complications and the degree of pancreatitis was estimated. Results: CT scans were graded as mild (n= 59), moderate (n= 82), and severe (n= 18). Abnormalities detected included perirenal stranding (n= 37 patients, 26 bilateral), perirenal fluid collections (n= 10 patients, one bilateral), ureteral encasement (n= 2 patients), renal vein thrombosis (n= 1 patient), and renal parenchymal abnormalities (n= 1 patient). The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of abnormalities was 75.5–79.2% and 59.8–100%, respectively. Except for stranding of the perirenal fat, no statistically significant differences between the presence of abnormalities and the severity of pancreatitis (moderate or severe) was observed with Fisher's exact test. Also, no preferential left-sided localization of complications was observed. Conclusions: The incidence of renal and perirenal complications from acute pancreatitis is higher than previously estimated (7%). We found no significant correlation between the prevalence of major complications and the severity of pancreatitis. These findings are important because these complications may have an impact on therapeutic strategy and can affect prognosis. Received: 31 March 1999/Revision accepted: 25 August 1999     

Abdominal visceral calcification in primary amyloidosis: CT findings

The computed tomographic (CT) findings of extensive visceral calcification involving both the liver and spleen in a patient with primary amyloidosis are presented. Although the CT imaging appearances of amyloidosis are often nonspecific, visceral calcification represents an important diagnostic clue for differentiating this entity from other infiltrative parenchymal diseases. Received: 19 March 1996/Accepted: 10 April 1996     

MRI of the abdomen with positive oral contrast agents for the diagnosis of inflammatory small bowel disease

Magnetic resonance imaging (MRI) is being used more often in the evaluation of inflammatory bowel diseases. A prerequisite for adequate image quality is the oral application of contrast medium, which can be administered with different modalities. Positive and negative oral contrast media can be used; in terms of diagnostic efficacy, there appears to be no relevant differences between them. Sequences usually are acquired using breath-hold or respiration-triggered protocols. The underlying principle is visualization of circumscribed thickening of the intestinal wall, which shows a pathologic pattern of contrast medium uptake. The available data suggest that MRI is equally as effective as enteroclysis in the primary diagnosis of Crohn's disease and actually more sensitive in the detection of extraintestinal manifestations such as fistulae or abscesses. Supporters of the method predict that MRI will replace enteroclysis in the long term.     

Perforations of the rectosigmoid colon induced by cleansing enema: CT findings in 14 patients

Background: We report the computed tomographic (CT) features of colorectal perforations caused by cleansing enema. Methods: We reviewed the medical records and CT studies of all patients with colorectal perforations caused by a cleansing enema. Results: Fourteen patients (10 men, four women; average age = 80 years) were included in the study. The most common presenting symptoms were severe abdominal pain and fever. CT was performed within 48 h after the event in most patients. Extraluminal air in the perirectal fat was the most frequent finding on CT and was present in all patients. Additional findings were extraperitoneal (n = 9), intraperitoneal (n = 3) and /or subcutaneous (n = 3) air, free fluid (n = 9), extraluminal feces (n = 8), and focal bowel wall thickening (n = 4). No leak of contrast from the rectum was observed in any patient including the one patient in whom contrast was administered rectally. Ten patients were treated by surgery; five recovered and the other five died. The other four patients were treated conservatively and all four died. Conclusion: The diagnosis of colorectal perforation can be made on CT. Because the diagnosis is not always suspected by the clinician, the radiologist may be the first to suggest it. Therefore, the radiologist should be familiar with the CT features of a potentially lethal, rectally induced perforation. Received: 19 April 2001/Revision accepted: 4 July 2001     

CT诊断实验性小肠闭袢性肠梗阻肠壁缺血程度的准确性

目的 探讨CT诊断兔小肠闭袢性肠梗阻肠壁缺血程度的价值.方法 新西兰大白兔54只,随机分为A、B、C三组, A组9只,结扎长约10～15 cm的小肠两端,形成单纯性闭袢;B组30只,同时结扎闭袢肠段的引流静脉;C组15只,在B组操作基础上同时结扎闭袢肠段的供血动脉.按预设的不同时间段行CT扫描,扫描结束后取材闭袢肠段3～5 cm进行组织学观察.将不同时间段小肠肠壁缺血程度的CT表现与相对应的病理诊断结果 进行比较.结果 A组9只,病理均表现为轻度肠缺血,CT正确诊断7只;B组30只,病理表现为轻度、中度和重度肠缺血,其中轻度9只,CT正确诊断6只;中度13只,CT正确诊断10只;重度8只,CT正确诊断7只.C组15只, 病理表现为中度和重度肠缺血,其中中度6只,CT正确诊断5只, 重度9只,CT正确诊断7只.结论 CT对小肠肠壁缺血程度判断的准确性高,对临床有参考价值.     

Primary small bowel tumors: a radiologic-pathologic correlation

Background: Primary small bowel tumors are rare and their preoperative diagnosis is unsatisfactory. The cornerstone of diagnosis remains contrast radiography. The present study was done to evaluate the radiologic findings of primary small bowel tumors as shown on enteroclysis and to correlate these observations with surgical and histopathologic findings. Methods: Seventy two patients with primary small bowel tumors identified by enteroclysis were evaluated. All the patients were subjected to jejunal biopsy or surgery. The diagnosis was established by histopathologic examination in all cases. Results: Radiologic findings were suggestive of benign tumors in 19 patients and malignant tumors in 31 patients. Nonspecific findings in the form of diffuse involvement of the small bowel were noted in 22 patients. There was 100% radiologic–surgical correlation. Leiomyomas and lymphomas were the most common benign and malignant tumors, respectively. Tumor specificities were 89.5% for benign tumors and 41.5% for malignant tumors. Conclusion: Distinctive morphologic patterns as shown on enteroclysis are highly suggestive of specific tumor types in the majority of cases. Received: 25 April 2000/Revision accepted: 20 September 2000     

CT and anal endosonography in the evaluation of electrically stimulated neoanal sphincter: a preliminary report

We report a preliminary experience concerning the postoperative assessment of three patients who underwent gracilis neosphincter operation for severe fecal incontinence and were studied by computed tomography and anal endosonography soon after gracilis transposition and later after 6–8 weeks of neuromuscular training. Morphologic assessment was correlated with physiologic testing (manometry). Continence was satisfactorily improved in all patients. Both imaging techniques demonstrated the anatomy of the transposed muscle. Computed tomography also assessed lead placement onto the gracilis nerve root and the completeness of muscle transposition around the anal canal. Anal endosonography provided a more accurate assessment of the relation between the neosphincter and residual external sphincter. Received: 3 April 1995/Accepted: 10 May 1995     

First experiences in CT-guided percutaneous transhepatic biliary decompression by means of real-time CT fluoroscopy

Background: Computed tomographic fluoroscopy (CTF), also called real-time CT, is increasingly used in interventional radiology but has not yet been recommended to guide percutaneous transhepatic biliary decompression (PTBD). We report our early clinical experiences with CTF-guided PTBD. Methods: Sixteen consecutive patients underwent PTBD under CTF guidance because of obstructive jaundice caused by malignant tumor (11 cases of carcinoma of the bile duct, four cases of pancreatic cancer, and one case of metastasis). CTF-guided PTBD was performed on a helical CT scanner and a surgical C arm. Main target parameters were the success and complication rates, the number of necessary punctures, the time needed for successful puncture of a suitable bile duct, and the patients' radiation exposure. Results: CTF-guided punctures of the bile duct for PTBD were successful on the first trial in 10 cases; in six patients, two hits were necessary. The time needed to hit a suitable bile duct was 6–21 s (median = 13 s). Therefore, the radiation exposure (skin) was 27–94.5 mSv. The additional implantation and stenting of the bile duct by means of the surgical C arm was uneventful in 15 cases. In one case, only external drainage could be achieved. Complications did not occur. Conclusion: CTF enables good visualization of the most suitable duct for puncture. Therefore, subsequent recanalization seems to be easier than other methods. Received: 19 June 2000/Accepted: 26 July 2000     

CT portography by direct intrasplenic contrast injection: a new technique

Background: The evaluation of percutaneous contrast injection into splenic parenchyma as an alternative technique for computed tomographic (CT) portography in the preoperative assessment of primary hepatobiliary tumors. Methods: Thirty-two patients underwent a nonenhanced CT scan of the liver, after which a 19-gauge, 10-cm-long needle was introduced into the splenic parenchyma under CT guidance. One hundred forty milliliters of contrast medium (200 mgI/mL; 28 g/I) were injected through this needle: first, a 20-mL bolus (in 5 s) and then 2 mL/s for 60 s. At the end of the bolus injection (5 s), 8-mm-thick contiguous axial scans of the liver were obtained. Results: The success rate of the procedure was 93.7% (30/32; two technical failures). The average time required for the entire study was 13 min and 50 s (range = 7 min 53 s to 25 min 17 s). Hepatic parenchymal enhancement was good in 24/30 (80%), moderate in 3/30 (10%), and unsatisfactory in caudal sections of the liver in 3/30 (10%). Artifactual perfusion defects were seen in 4/30 (13%) due to inadvertant injection of small quantities of air. Intrasplenic subcapsular contrast accumulation occurred in 56.2% (18/32; minimal 15, moderate 3), extrasplenic contrast leakage in 12.5% (4/32), and left shoulder pain in 18.7% (6/32). No major complications were observed. Conclusions: Direct intrasplenic contrast injection for CT portography is a simple, effective, and safe technique with a high success rate and requires significantly less time and lower doses of contrast medium; it also eliminates angiography, indwelling arterial catheters, and patient transfers from angiography to the CT area. Received: 5 November 1997/Accepted after revision: 11 February 1998     

Logistic advantages of four-section helical CT in the abdomen and pelvis

Background: Multisection helical computed tomography (CT) has the potential for providing data sets with better section profiles, more anatomic coverage, and shorter breath-holding periods. Our purpose was to quantitate these advantages in a clinical setting when imaging the abdomen and pelvis. Methods: CT parameters including collimation, timing, z-axis coverage, and milliamperes were gathered retrospectively for the image set of both single-section (GE CT/i with 0.8-s rotation) and four-section (GE QX/i Lightspeed with 0.8-s rotation) helical CT scanners. Data were recorded for the abdomen and pelvis CT (n= 30 each), dual-phase liver CT including the pelvis (n= 15 each), and dual-phase pancreas CT (n= 15 each). Results: The abdominal and pelvic CT averaged 128.4 ± 5.4 s for single-section scanners (70-s delay, two breath-holds of 21.1 and 17.7 s with a 19.5-s interscan delay) and 92.2 ± 2.2 s for the four-section scanner (70-s delay and a 22.2-s breath-hold; p < 0.0001). For the dual liver and pelvis CT, single-section scanners averaged 119.9 ± 7.5 s (30-s delay, 15.8-s arterial phase, 20.0-s interscan delay, 21.2-s venous phase, 19.5-s interscan delay, and 14.2 s for the remaining abdomen and pelvis), whereas the four-section scanner averaged 86.8 ± 2.5 s (30-s delay, 6.7-s arterial phase, 27.9-s interscan delay, and 21.8-s venous phase including the pelvis; p < 0.0001). For the dual pancreas CT, single-section scanners averaged 86.7 ± 2.5 s (20-s delay, 28.3-s arterial phase, 17.8-s interscan delay, 21.7-s venous phase), whereas the four-section scanner averaged 78.0 ± 2.9 s (20-s delay, 9.7-s arterial phase, 30.7-s interscan delay, 13.0-s venous phase; p < 0.0001). Conclusion: CT scanners having four-section technology can reduce overall data acquisition times by 10–30% and total milliamperes by 50–60% depending on the protocol with thinner slice profiles. RID=" ID=" <E5>Correspondence to:</E5> R. C. Nelson Received: 8 December 1999/Revision accepted: 22 March 2000