Colonoscopy findings in end-stage liver disease patients with incidental CT colonic wall thickening

OBJECTIVE: Colonic wall thickening may occur in patients with end-stage liver disease. This study was conducted to correlate colonoscopy with CT-detected colonic wall thickening in this group of patients to assess their radiologic and clinical relevance. CONCLUSION: Our results suggest that CT findings of colonic wall thickening in end-stage liver disease should be considered benign, and colonoscopy is unnecessary for the evaluation of malignancy or colitis unless it is clinically indicated.     

Small-bowel wall thickening related to a long intestinal tube: incidental CT finding mimicking a pathologic condition

PURPOSE: The purpose of this work is to describe the CT findings of small-bowel wall thickening related to a long intestinal tube in patients with bowel obstruction and to discuss the mechanism of this incidental finding. METHOD: Ten consecutive patients with intubation of a long intestinal tube for bowel obstruction were studied retrospectively. Five cases were diagnosed as colon cancer, three as postoperative adhesion, one as Meckel diverticulitis, and one as internal hernia of the small bowel. The history and imaging studies of these patients were reviewed. RESULTS: Small-bowel wall thickening was demonstrated in 6 of the 10 patients on CT. All findings of small-bowel wall thickening were observed along the long intestinal tube. Multiple accordion-shaped pleats were seen in five patients on longitudinal sections of the small bowel. CONCLUSION: Although definitive pathologic proof is lacking, small-bowel wall thickening related to a long intestinal tube was thought to represent a multiply "pleated" normal small bowel along a long intestinal tube.     

Detection of colorectal lesions: lower-dose multi-detector row helical CT colonography compared with conventional colonoscopy

PURPOSE: To compare the performance of lower-dose multi-detector row helical computed tomographic (CT) colonography with that of conventional colonoscopy in the detection of colorectal lesions. MATERIALS AND METHODS: One hundred fifty-eight patients underwent multi-detector row helical CT colonography (beam collimation, 4 x 2.5 mm; table feed, 17.5 mm/sec; voltage, 140 kV; and effective dose, 10 mAs) followed by conventional colonoscopy. Conventional colonoscopy served as the reference standard. Two radiologists interpreted CT colonographic images to assess the presence of polyps or carcinomas. Sensitivity was calculated on both a per-polyp and a per-patient basis. In the latter, specificity and positive and negative predictive values were also calculated. Weighted CT dose index was calculated on the basis of measurements obtained in a standard body phantom. Effective dose was estimated by using commercially available software. RESULTS: CT colonography correctly depicted all 22 carcinomas (sensitivity, 100%) and 52 of 74 polyps (sensitivity, 70.3%). Sensitivity for detection was 100% in all 13 polyps 10 mm or larger in diameter, 83.3% in 20 of 24 polyps 6-9 mm, and 51.3% in 19 of 37 lesions 5 mm or smaller. With regard to the per-patient analysis, CT colonography had a sensitivity of 96.0%, a specificity of 96.6%, a positive predictive value of 94.1%, and a negative predictive value of 97.7%. The total weighted CT dose index for combined prone and supine acquisitions was 2.74 mGy. The simulated effective doses for complete CT colonography were 1.8 mSv in men and 2.4 mSv in women. CONCLUSION: Lower-dose multi-detector row helical CT colonography ensures substantial dose reduction while maintaining excellent sensitivity for detection of colorectal carcinomas and polyps larger than 6 mm in diameter.     

胃壁增厚的CT表现

目的：探讨胃良恶性病变胃壁增厚的CT表现特征,提高良恶性鉴别能力。方法：回顾性分析经病理或临床诊断明确的42例胃壁增厚的CT表现,并以胃壁增厚的程度、对称性、强化特点和分布等以鉴别良恶性病变的特征性CT表现。结果：肿块型增厚19例;条状或带状增厚5例;溃疡型增厚5例;蒂型增厚1例;结节型增厚6例;不规则型增厚6例。其中,恶性15例,良性26例,未定型1例。结论：胃壁增厚在CT上表现直观、清晰,结合胃壁增厚的程度、类型、强化等特点可以鉴别其良恶性。     

Extracolonic and incidental findings on CT colonography (virtual colonoscopy)

OBJECTIVE: The objective of our study was to prospectively determine the frequency and clinical importance of extracolonic findings on CT colonography in symptomatic patients. SUBJECTS AND METHODS. One hundred eleven symptomatic patients referred for colonoscopy underwent CT colonography before colonoscopy. Helical CT from the diaphragm to the symphysis was performed with the patient in the supine and prone positions after rectal air insufflation. Image interpretation was done on a digital workstation. Extracolonic findings were classified as minor, moderate, or major according to potential clinical importance. Patient records, with a follow-up time of about 3 years, were reviewed to determine final diagnoses. RESULTS: Twenty-six (23%) of the patients had CT findings of major importance such as lymphadenopathy (n = 7), aortic aneurysm (n = 6), suspected solid hepatic masses (n = 5), and suspected solid renal masses (n = 4). Fifty-eight patients (52%) had findings of moderate importance such as gallstones (n = 16), indeterminate renal masses (n = 9), adrenal masses with benign appearance (n = 8), and hiatal hernia (n = 7). Forty-six patients (41%) had no or only minor findings, such as renal cysts (n = 34), renal calcifications (n = 19), and hepatic cysts (n = 14). Review of patient records showed that CT colonography contributed to the detection of major, previously unknown extracolonic disorders in 14 (13%) of the 111 patients. CONCLUSION: Potentially important extracolonic findings were revealed in 23% of the patients, leading to additional diagnostic or therapeutic considerations. Some of these findings were clinically important, whereas others were previously known or led to unnecessary workup. This finding must be taken into account when CT colonography is considered for routine diagnostic workup or screening.     

False-positive CT diagnosis of gallstones due to thickening of the gallbladder wall

An erroneous CT diagnosis of cholelithiasis was made at our institution during the past year in seven patients who had thickening of the gallbladder wall. In all cases the mucosa, which had a high attenuation value, was misinterpreted as a calcified stone, and the low-attenuation thickened submucosa was misinterpreted as intraluminal bile surrounding the stone. Depending on the attenuation of the actual intraluminal bile, the pseudostone appeared peripherally calcified (five patients) or uniformly calcified (two patients). Careful analysis of the position and configuration of a suspected stone and of the outer margin of the gallbladder can help avoid an incorrect CT diagnosis of gallstones when high-attenuation thickened mucosa simulates a gallstone and low-attenuation submucosa looks like surrounding bile.     

CT evaluation of wall thickening in the alimentary tract

Computed tomography (CT) of the alimentary tract, when performed with adequate distention of the organ being examined and in the true axial plane, provides valuable information about the intramural or extramural extent of pathologic conditions. Neoplastic, vascular, and inflammatory diseases can all result in wall thickening of the alimentary tract. Wall thicknesses greater than 5 mm in the esophagus, stomach, and colon and 4 mm or greater in the small bowel are considered abnormal. If the thickened wall has a target or double-ringed appearance, it is most likely caused by benign disease. In general, the CT findings of asymmetric or focal wall thickening, nodularity, and thickening greater than 1.5 cm suggest a malignant process. Although it is commonly associated with benign disease, diffuse thickening can also result from some infiltrating malignant diseases. Careful review of CT scans for evidence of metastatic disease and adenopathy and correlation with clinical information aid in the differential diagnosis.     

Contrast-enhanced CT colonography with 64-slice MDCT compared to endoscopic colonoscopy in the follow-up of patients after colorectal cancer resection

BackgroundSeventy percent of newly diagnosed colorectal cancer cases are potential candidates for curative surgery, but after resection, in 30%, the tumor will recur.Postoperative follow-up includes endoscopic colonoscopy (EC) and computed tomography (CT). There have been only a few publications on the use of contrast-enhanced CT colonography (CECTC) in the follow-up of these patients.MethodsTwenty-nine consecutive patients after resection of colorectal cancer underwent CECTC and EC on the same day. CECTC studies were reviewed for identification of strictures, recurrence, polyps and metastases.ResultsThe anastomosis was identified in 96% of patients on CECTC and in 82% on endoscopic colonoscopy. One stricture was identified by both techniques. One extraluminal recurrence was depicted only on CECTC. Sensitivity in detecting polyps was per polyp 93% and per patient 100%.ConclusionCECTC performed on a 64-slice multidetector CT is reliable in imaging the postoperative colon for the follow-up of patients after resection of colorectal cancer.     

Gastrointestinal wall thickening in patients with cirrhosis: frequency and patterns at contrast-enhanced CT

PURPOSE: To determine the frequency and patterns of gastrointestinal wall thickening at contrast material-enhanced computed tomography (CT) in patients with cirrhosis. MATERIALS AND METHODS: Three radiologists retrospectively assessed the contrast-enhanced abdominal CT scans of 77 patients with cirrhosis and 100 patients without cirrhosis for gastrointestinal wall thickening from the stomach through the descending colon. The frequencies of wall thickening were determined in the cirrhosis and in the control groups and were compared by using the Fisher exact test. The segmental distribution, symmetry, and enhancement pattern were evaluated in all patients with cirrhosis and gastrointestinal wall thickening. RESULTS: Gastrointestinal wall thickening was seen in 49 (64%) patients with cirrhosis and in seven (7%) control subjects (P <.005). The jejunum and ascending colon were the most common sites of gastrointestinal wall thickening; each was involved in 32 (42%; 95% CI: 30%, 53%) patients. The scans of 30 (61%; 95% CI: 47%, 75%) patients with gastrointestinal wall thickening showed multisegmental distribution. Gastrointestinal wall thickening was concentric and homogeneous in all patients with cirrhosis. CONCLUSION: Gastrointestinal wall thickening is common on contrast-enhanced abdominal CT scans in patients with cirrhosis. It frequently involves multiple segments. The jejunum and ascending colon are the most common sites of involvement.     

Appendiceal wall thickening at CT in asymptomatic patients with extraintestinal malignancy may mimic appendicitis

The purpose of this study was to describe the CT appearance and determine the prevalence of thick-walled appendices in patients with an extraintestinal primary malignancy. This potential mimic of appendicitis may occur in up to 2% of cancer patients. Awareness of this pitfall is important to avoid unnecessary laparotomy in this patient population.     

Segmental wall thickening in the colonic loop distal to colonic carcinoma at CT: importance and histopathologic correlation

PURPOSE: To determine the importance of the finding of segmental wall thickening in the colonic loop distal to colonic carcinoma at computed tomography (CT) by means of histopathologic correlation. MATERIALS AND METHODS: Thirteen consecutive patients whose helical CT scans showed segmental wall thickening (>1 cm in maximal width, >5 cm in length) in the colonic loop distal to colonic carcinoma were included. The thickness and length of an involved segment, location, morphologic tumor type, CT patterns of wall thickening, and pericolic changes were evaluated. Surgical pathologic findings in all 13 patients were correlated with CT findings. RESULTS: The involved segment distal to the colonic carcinoma showed circumferential wall thickening with a preserved wall layer pattern at CT. Pericolic changes of varying degrees were seen in 10 patients. Histopathologic examination revealed submucosal and subserosal edema (n = 6), chronic inflammation and fibrosis (n = 5), or both (n = 1), and no histopathologic alteration (n = 1). The tumors were mostly fungating (n = 11), larger than 5 cm in the greatest dimension (n = 12), located in the ascending colon (n = 10), and extended to pericolic adipose tissue (n = 11). CONCLUSION: Colonic carcinoma, especially a large fungating type involving the ascending colon with pericolic infiltration, can produce segmental wall thickening in the distal segment at CT, which represents edema or colitis at histopathologic examination.     

Frequency and CT patterns of bowel wall thickening proximal to cancer of the colon

OBJECTIVE: This study was performed to determine the frequency and patterns of colon wall thickening seen on CT of patients with adenocarcinoma of the colon. MATERIALS AND METHODS: Preoperative abdominal and pelvic CT scans of 185 patients with surgically proven adenocarcinoma of the colon were retrospectively evaluated by three abdominal radiologists for the presence of colon obstruction and colon wall thickening proximal to the colon adenocarcinoma. The distributions and patterns of colon wall thickening were categorized by consensus. CT findings were compared with pathologic findings. Fisher's exact test was used to determine the statistical significance of any associations. RESULTS: Of 185 patients, CT findings of 20 (10.8%) showed colon wall thickening. Of these, the adenocarcinoma obstructed the colon in 19 patients (p < 0.01). Colon obstruction was partial in 10 patients (53%) and complete in nine (47%). Colon wall thickening was contiguous to the tumor in 14 (70%) patients and noncontiguous in six (30%). Segmental and pancolonic, patchy and diffuse, and dependent and nondependent colon wall thickening was observed in 10 patients (50%) in each category. Associated small-bowel wall thickening was shown in 10 (50%) of the 20 patients. Pathologic examination showed colon wall thickening to be due to edema in all cases. CONCLUSION: Colon wall edema can occur proximal to colon adenocarcinoma, is almost always associated with colon obstruction, and is predominantly contiguous with the obstructing adenocarcinoma.     

Concentric bladder wall thickening due to haemorrhage following suprapubic aspiration: ultrasound and CT features

A 5-week-old baby with coagulopathy due to hepatic mitochondrial disorder developed a bladder haematoma secondary to suprapubic urine aspiration. Unlike previously reported cases, the haematoma manifested itself only as concentric thickening of the bladder wall without an intraluminal component. The ultrasound and CT features are described. Recognition of these findings is important when discussing the differential diagnosis of bladder wall thickening.     

MR colonography with limited bowel preparation compared with optical colonoscopy in patients at increased risk for colorectal cancer

PURPOSE: To prospectively evaluate the diagnostic performance of magnetic resonance (MR) colonography by using limited bowel preparation in patients with polyps of 10 mm or larger in diameter in a population at increased risk for colorectal cancer, with optical colonoscopy as the reference standard. MATERIALS AND METHODS: The institutional review boards of all three hospitals approved the study. All patients provided written informed consent. In this multicenter study, patients undergoing colonoscopy because of a personal or family history of colorectal cancer or adenomatous polyps were included. Two blinded observers independently evaluated T1- and T2-weighted MR colonographic images obtained with limited bowel preparation (bright-lumen fecal tagging) for the presence of polyps. The limited bowel preparation consisted of a low-fiber diet, with ingestion of lactulose and an oral gadolinium-based contrast agent (with all three major meals) starting 48 hours prior to imaging. Results were verified with colonoscopic outcomes. Patient sensitivity, patient specificity, polyp sensitivity, and interobserver agreement for lesions of 10 mm or larger were calculated for both observers individually and combined. RESULTS: Two hundred patients (mean age, 58 years; 128 male patients) were included; 41 patients had coexistent symptoms. At colonoscopy, 12 patients had 22 polyps of 10 mm or larger. Per-patient sensitivity was 58% (seven of 12) for observer 1, 67% (eight of 12) for observer 2, and 75% (nine of 12) for both observers combined for polyps of 10 mm or larger. Per-patient specificity was 95% (178 of 188) for observer 1, 97% (183 of 188) for observer 2, and 93% (175 of 188) for both observers combined. Per-polyp sensitivity was 55% (12 of 22) for observer 1, 50% (11 of 22) for observer 2, and 77% (17 of 22) for both observers combined. Interobserver agreement was 93% for identification of patients with lesions of 10 mm or larger. CONCLUSION: In patients at increased risk for colorectal cancer, specificity of MR colonography by using limited bowel preparation was high, but sensitivity was modest.     

CT虚拟结肠镜对早期筛查结直肠癌的研究进展

CT虚拟结肠镜（CTVC）应用临床以来,在结直肠癌（CRC）的诊断方面越来越显示出其独特的优势,较短的检查时间、较低的辐射剂量和高质量的成像使其成为CRC的早期筛查手段。笔者主要对CTVC在CRC早期筛查方面的进展和临床价值进行综述。     

螺旋CT仿真内窥镜诊断大肠息肉初探

目的 探讨螺旋ＣＴ仿真内窥镜对大肠息肉的诊断价值和临床意义。方法 １８例有反复便血、慢性腹泻、腹痛的病人行１次屏气全结肠容积扫描,重叠重建图像并输至工作站进行四维容积重建（４Ｄ ａｎｇｉｏ）,选择导航者（Ｖｏｙａｇｅｒ）软件和合适阈值及透明度,航进观察大肠黏膜。全部资料经纤维结肠镜和（或）手术证实。结果 １８例中发现大肠息肉９例,均为多发,共检出息肉７１枚,直径２～２０ｍｍ,其中升结肠１枚,结肠肝     

Colonic wall thickening in patients with cirrhosis: CT findings and clinical implications

OBJECTIVE: The purpose of this study was to determine the prevalence and spectrum of colonic wall changes in patients with cirrhosis and to determine the association between these colonic wall changes and portal hypertension. MATERIALS AND METHODS: Abdominal CT examinations of 57 patients with cirrhosis were evaluated for colonic abnormalities including bowel wall thickening and pneumatosis. The degree and extent of colonic involvement, other CT features of cirrhosis including ascites and portal hypertension, and clinical symptoms were recorded. A correlation was made with available colonoscopy, exploratory laparotomy, and pathologic results. RESULTS: Colonic wall abnormalities were seen in 37% (21/57) of the patients with cirrhosis, 25% (14/57) of whom had isolated or predominantly right-sided colonic changes. Abnormal bowel wall thickening (ranging from 6 mm to 3 cm in thickness) was present in 35% of the patients. Pneumatosis was found in 4% of the patients. Of the 18 liver transplant recipients who had CT examinations before and after liver transplantation, colonic changes were seen in 44% preoperatively but in only 6% postoperatively. Isolated right-sided colonic changes and diffuse colonic changes were associated with varices in 93% and 100% of the patients, respectively; with ascites in 93% and 100%, respectively; and with splenomegaly in 83% and 86%, respectively. Specific or focal bowel symptoms were present in only 29% of the patients with colonic changes, whether the changes were diffuse or isolated to the right side. CONCLUSION: Thirty-five percent of the patients with severe cirrhosis who underwent CT were shown to have colonic wall thickening; two thirds of these patients had thickening limited predominantly to the right colon. We postulated that predominantly right-sided colonic wall thickening may be related to changes in blood flow and hydrostatic pressures caused by portal hypertension. Many patients with isolated or predominately right-sided colonic wall thickening did not have specific or focal bowel symptoms, and in most patients, the colonic wall thickening resolved after successful liver transplantation, requiring no further testing. On the other hand, we found that pneumatosis or severe diffuse colonic wall thickening may indicate a more serious colonic problem such as ischemia or infection with Clostridium difficile and should prompt further investigation.