A comparative study of CT and barium enema examination in diagnosis of peritoneal metastasis from gastric carcinoma

OBJECTIVE: To compare the results of CT and barium enema examination in the diagnosis of peritoneal metastasis from gastric carcinoma. MATERIALS: Peritoneal metastases were pathologically confirmed in nine patients with gastric carcinoma who had had abdominal CT and barium enema examinations prior to surgery. METHODS AND RESULTS: Five patients were reported to have colonic wall rigidity on preoperative barium enema examination. Review of the images indicated that six cases showed rigidity. On the other hand, no CT findings suggestive of peritoneal metastasis were reported in eight patients without ascites. No patients were indicated to have intraperitoneal nodules. For the retrospective evaluation, we changed the diagnostic procedure: the CT window setting was changed in wide window width (from 250 Hounsfield units (HU) to 400HU)and low window level (50-60HU to 0 HU), and reading mode was changed to a cine paging mode with a picture archiving and communication system (PACS) instead of hard-copy review. It followed that intraperitoneal nodules suggestive of peritoneal metastasis were detected in eight patients. CONCLUSION: On conventional image reading, barium enema examination is of greater assistance than CT examination for detecting peritoneal metastasis from gastric carcinoma. However, the new CT reading method with PACS is more sensitive than barium enema examination for diagnosing peritoneal metastasis.     

Tumor recurrence after radiofrequency thermal ablation of hepatic tumors: spectrum of findings on dual-phase contrast-enhanced CT.

OBJECTIVE: We conducted this study to determine the spectrum of CT findings of tumor recurrence after radiofrequency ablation of primary and secondary malignant hepatic tumors. MATERIALS AND METHODS: Twenty-five patients, 10 with hepatocellular carcinoma (HCC) and 15 patients with metastases who developed tumor recurrence after radiofrequency ablation of hepatic neoplasms, formed the study population. Three observers reviewed the CT scans of these patients and evaluated the location (local intrahepatic, remote intrahepatic, or extrahepatic) of all recurrent lesions and the morphology and enhancement characteristics of local intrahepatic recurrences. RESULTS: Local intrahepatic recurrences were seen in nine patients (90%) and 11 patients (73%); remote intrahepatic recurrences, in five patients (50%) and seven patients (45%); and extrahepatic recurrences, in zero and six patients (40%) with recurrent HCC and recurrent metastases, respectively. Of the 12 nodules of local intrahepatic recurrences in HCC and the 24 in metastases, the patterns of local intrahepatic recurrences were of nodular, halo, and gross enlargement types in eight (67%) and nine (38%), four (33%) and six (38%), and zero and nine (37%) nodules in HCC and hepatic metastases, respectively. The number of local intrahepatic recurrent lesions enhancing in the arterial phase was significantly greater in HCC. CONCLUSION: Tumor recurrences occurred at intra- and extrahepatic sites after radiofrequency ablation of hepatic neoplasms. The local intrahepatic recurrences appeared in three patterns: nodular, halo, or gross enlargement. The sites of recurrence and the morphologic patterns of local intrahepatic tumor recurrence differed between primary and secondary hepatic neoplasms.     

胃肠系统淋巴瘤的X线与CT诊断(附20例分析)

目的分析胃肠系统淋巴瘤的CT、胃肠造影表现。材料与方法回顾性分析了20例胃肠系统淋巴瘤的胃肠道造影及CT影像资料，其中男16例，女4例，年龄25～71岁。20例均行胃肠道造影检查，15例行腹部CT检查。所有病例均经病理证实。结果1．胃肠道气钡造影检查①浸润型胃8例，小肠1例；②肿块型胃5例；③溃疡型胃2例；④息肉型近端空肠1例，末端回肠及盲肠3例。2．CT表现向心性壁厚20～25mm局限性肿块，脾大，脾内低密度灶2例；淋巴结增大。结论1．气钡双重造影是诊断胃肠系统淋巴瘤的首选方法，CT检查可以补充其他器官及淋巴结情况。2．胃肠系统淋巴瘤应与其他疾病相鉴别。     

Small cell carcinoma of the colon: barium study and CT findings

Extrapulmonary small cell carcinoma is a rare neoplasm. It is an aggressive malignant tumour characterized by rapid local progression and early metastasis. We report a case of small cell carcinoma arising in the transverse colon in a 34-year-old man who presented with epigastric pain. On CT, a poorly enhancing bulky mass encircling the transverse colon with extensive regional lymph node metastases was observed. A segmental annular narrowing with thick interhaustral folds of the transverse colon was found by barium enema examination. This is the first report of barium study and CT findings of extrapulmonary small cell carcinoma of the colon.     

Colorectal carcinoma: a radiologic and clinical review

A profusion of imaging techniques is currently used for evaluating patients with suspected or known colorectal carcinoma. In most institutions, the combination of flexible sigmoidoscopy and a well-performed barium enema study should be retained as a more cost-effective, safe, and complete method of examination than colonoscopy. Endosonography appears to be promising for evaluating preoperatively the local extent of rectal carcinoma. CT is being challenged by MR imaging as the most sensitive modality for detecting liver metastases, but CT currently remains the technique of choice for evaluating recurrent disease and its extent. The diversity of available modalities will ensure that the radiologist remains at the forefront in the clinical investigation of colorectal carcinoma.     

大肠癌的螺旋CT三维重建研究及外科应用评价

目的 :探讨螺旋CT三维重建技术在大肠癌外科术前诊断中的价值。材料和方法 :选 2 0例有低张气钡灌肠造影及病理证实的大肠癌 ,行低张充气螺旋CT扫描 ,表面覆盖显示 (SSD)、容积漫游技术 (VRT)、多平面重组 (MPR)等三维重建 ;另 10例行常规及低张注生理盐水CT检查。本法与造影、常规CT、低张注水CT及手术、病理对照观察。结果 :常规CT检出率为 4/ 10 ;低张注水CT检出率为 7/ 10 ;低张气钡灌肠造影检出率为 2 0 / 2 0 ;螺旋CT三维重建检出率为 2 0 / 2 0。前三者在检出率或观察内容上均有各自限度 ,后者可弥补。结论 :SSD、VRT可显示 6mm隆起病变和 3mm管腔狭窄 ,VRT可显示 1mm细沟凹陷 ;MPR对轻微的肠壁增厚、僵硬很敏感 ,能准确判断病灶外侵程度 ;SSD酷似内窥镜 ,VRT可比低张气钡灌肠造影 ,SCT三维重建可一法多用。     

螺旋CT对射频消融治疗肝脏恶性肿瘤的疗效评价

目的　探讨螺旋CT在肝脏恶性肿瘤射频消融治疗后随访过程中的价值。方法　对 3 6例超声引导下经皮穿刺射频消融治疗的肝脏恶性肿瘤患者 (2 9例原发性肝癌和 7例转移性肝癌 )定期进行螺旋CT双期增强扫描检查 ,观察射频消融的效果及肿瘤复发的情况。结果　肿瘤残留或原位复发的主要征象是消融区的边缘呈带状或结节样强化 ,或在随访CT复查中 ,肿瘤的体积不断增大。在射频消融治疗后的首次CT复查中 ,2 8例 (77.8% )肿瘤出现完全坏死。在随后的CT随访复查中 ,2例 (5.6% )出现肝内原位复发 ,4例 (11.1% )出现肝内异位复发。结论　对于合适的肝脏恶性肿瘤 ,射频消融是一种疗效确切的肿瘤局部治疗方法 ,在其疗效评价和长期随访过程中 ,螺旋CT双期增强扫描是有效的影像检查手段     

Intra-individual comparison of patient acceptability of multidetector-row CT colonography and double-contrast barium enema

AIMS: To compare the subjective acceptability of CT colonography in comparison with barium enema in older symptomatic patients, and to ascertain preferences for future colonic investigation. MATERIALS AND METHODS: The study population comprised 78 persons aged 60 years or over with symptoms suggestive of colorectal neoplasia, who underwent CT colonography followed the same day by barium enema. A 25-point questionnaire was administered after each procedure and an additional follow-up questionnaire a week later. Responses were compared using Wilcoxon matched pairs testing, Mann-Whitney test statistics and binomial exact testing. RESULTS: Participants suffered less physical discomfort during CT colonography (p = 0.03) and overall satisfaction was greater compared with barium enema (p = 0.03). On follow-up, respondents reported significantly better tolerance of CT colonography (p = 0.002), and were less prepared to undergo barium enema again (p < 0.001). Of 52 subjects expressing an opinion, all preferred CT to barium enema. CONCLUSION: Patient satisfaction was higher with CT colonography than barium enema. CT colonography caused significantly less physical discomfort and was overwhelmingly preferred by patients.     

Comparison of radiologists' confidence in excluding significant colorectal neoplasia with multidetector-row CT colonography compared with double contrast barium enema

The aim of this study was to compare the confidence of experienced radiologists in excluding colonic neoplasia with CT colonography (CTC) compared with barium enema. 78 patients (median age 70 years, range 61-87 years, 44 women) underwent same day CTC and barium enema. Two radiologists experienced in reporting barium enema assessed whether the examination had excluded a polyp 6 mm or greater as "yes", "probably" or "no" for each of 6 colonic segments. Two different radiologists experienced in CTC independently performed the same assessment on the CT datasets. Responses were compared using a paired exact test. Formal barium enema and CT reports were compared with any endoscopic examination performed within 1 year. Studies reporting polyps 6 mm+ in patients not subsequently undergoing endoscopy were reviewed by two independent observers. Radiologists stated they had confidently excluded a significant lesion in 314 (71%) and 382 (86%) of 444 segments with barium enema and CTC, respectively (p<0.001). Confidence was significantly higher with CTC in the in the descending and ascending colon (p = 0.02 and p<0.001, respectively), and caecum (p<0.001). 22 patients underwent some form of endoscopy. Of five patients with proven colorectal neoplasia (including two with cancer), CTC and barium enema correctly identified five and three, respectively. In 56 patients not undergoing endoscopy, CTC reported 17 polyps 6 mm+, of which 16 were retrospectively classified as definite or probable. 11 could not be identified on the barium enema, even in retrospect. Confidence in excluding polyps 6 mm or larger is significantly greater with CT colonography particularly in the proximal colon.     

Rectal and sigmoid involvement secondary to carcinoma of the prostate.

Three types of involvement of the rectum and recto-sigmoid by carcinoma of the prostate are reviewed through an analysis of eight cases. A fourth type with subserosal metastatic implant of the proximal sigmoid may occasionally be encountered. The roentgenographic findings are not pathognomonic, but are characteristic of extrinsic involvement of the bowel wall. When clinical symptoms are predominantly related to the bowel, carcinoma of the prostate is usually advanced. All patients presented with bone metastases, uretero-hydronephorsis, lack of function of one kidney, or both bone metastases and urinary tract obstruction. Rectoscopy and biopsy are helpful. However, biopsy specimens often show non-diagnostic features in secondary malignancy. Correct diagnosis is important, since there is a difference in treatment of primary carcinoma and of secondary involvement of the rectum by prostatic carcinoma. A diagnostic challenge exists if the patient is evaluated by barium enema examination for primary bowel symptoms, in particular, large bowel obstruction. At this time intravenous pyelography and bone survey for metastases may not be available to suggest the correct diagnosis. More widespread use of barium enema examinations in the evaluation of advanced carcinoma of the prostate is suggested, since the type of rectal disease shown on barium enema study was not clinically suspected in five of eight patients. The prognosis is usually unfavorable because of advanced carcinoma. Survival often does not exceed several months to one year. However, one of our patients is still well after three years of hormonal therapy.     

Transitional cell carcinoma of the bladder: patterns of recurrence after cystectomy as determined by CT

CT scans have been recommended for examination of patients at risk for recurrent transitional cell carcinoma after cystectomy. For CT to be useful in this regard, the location and type of recurrences must be known, so that appropriate scans can be made. Therefore, we retrospectively studied CT scans in 27 postcystectomy patients with recurrent transitional cell carcinoma of the bladder to identify the type and location of the recurrent disease. Recurrence was documented by biopsy in 18 patients and by progression of disease shown on serial CT scans in nine patients. All 27 patients had pelvic CT, and 23 had concomitant abdominal CT. Tumor recurred at the cystectomy site in 10 (37%) of 27 patients, pelvic adenopathy was present in 18 (67%) of 27 patients, and retroperitoneal adenopathy was present in 13 (57%) of 23 patients. Tumor recurrence at the cystectomy site was associated with pelvic adenopathy in seven of 10 patients, and the cystectomy site was the solitary site of disease in the remaining three patients. Conversely, in 11 of 18 patients with pelvic adenopathy no recurrence was seen at the cystectomy site. Combined retroperitoneal and pelvic adenopathy was identified in 11 of 23 patients, but two patients had retroperitoneal lymphadenopathy as their only site of recurrence. Hepatic metastases were seen in seven (30%) of 23 patients; six of these seven patients had metastases elsewhere. In four of five patients in whom underestimation of recurrent disease occurred, the deep pelvis and/or deep perineal space were involved. Our results show that the pelvis is the most common site for recurrence. Cystectomy site or retroperitoneal nodal recurrences are usually accompanied by pelvic adenopathy, but the converse is not as common. Our findings of deep perineal and isolated abdominal recurrences indicate that proper protocol for CT follow-up of the postcystectomy patient should include abdominal scans and scans through the perineum.     

Recurrent gallbladder carcinoma along laparoscopic cholecystectomy port tracks: CT demonstration.

PURPOSE: To describe the computed tomographic (CT) appearance of recurrent gallbladder carcinoma along port tracks after laparoscopic cholecystectomy and to assess the effect of recurrence on patient care. MATERIALS AND METHODS: Seventeen abdominal CT scans in 16 of 19 consecutive patients who underwent hepatic resection for gallbladder carcinoma diagnosed at laparoscopic cholecystectomy were reviewed retrospectively. Medical records were reviewed to determine the clinical effect of tumor recurrence along a port track. RESULTS: CT revealed 12 tumor recurrences along laparoscopic port tracks in six (32%) patients (mean, two recurrences per patient; range, one to four per patient). Eight (67%) CT-depicted recurrences appeared homogeneous, and nine (75%) directly involved subjacent omental fat. The mass was the only site of recurrence at CT in two (33%) patients. The presence of an abdominal wall tumor recurrence affected patient care in four (67%) of six patients. Histopathologic examination results confirmed recurrent tumor in all five (100%) patients who underwent biopsy. CONCLUSION: Tumor recurrence along port tracks is a potential complication of laparoscopic cholecystectomy when gallbladder carcinoma is present, even after subsequent hepatic resection is performed for attempted cure. Recurrences appear as a new or enlarging abdominal wall mass, often involving subjacent omental fat, and may be the only site of recurrent disease at CT. Demonstration of abdominal wall tumor recurrence affects patient care.     

Ileocecal valve: spectrum of normal findings at double-contrast barium enema examination

PURPOSE: To characterize the spectrum of normal findings of the ileocecal valve at double-contrast barium enema examination to allow differentiation between a normal valve and one infiltrated by tumor. MATERIALS AND METHODS: A search of radiology and endoscopy files showed 106 patients who underwent double-contrast barium enema examination and colonoscopy. The radiographic images were reviewed by two authors to determine the morphology of the ileocecal valve and to evaluate whether it appeared normal or abnormal. The radiographic data were then correlated with endoscopic and pathologic findings. RESULTS: The ileocecal valve was visible in 91 (86%) of 106 patients. It was round or ovoid in 71 patients (78%) and triangular in 20 (22%). In the 88 patients with a normal valve at colonoscopy, mean valve height was 1.7 cm, and mean width was 2.8 cm. The valve was smooth in 75 patients (85%) and smoothly lobulated in 13 (15%). The lips of the valve were symmetric in 77 patients (88%) and asymmetric in 11 (12%). All 87 patients with a normal valve at double-contrast barium enema examination had a normal valve at colonoscopy, whereas the two patients with a valve suspicious for tumor at barium enema examination had neoplasms (one carcinoma and one villous adenoma) at colonoscopy. CONCLUSION: The ileocecal valve may show a spectrum of normal findings at double-contrast barium enema examination and may appear as a round, ovoid, or triangular structure with a maximal height of nearly 4 cm. The valve may be large, asymmetric, or smoothly lobulated, even in the absence of tumor.     

Metastases of colorectal carcinoma: comparison of soft- and hard-copy helical CT interpretation

PURPOSE: To compare soft- and hard-copy computed tomographic (CT) image interpretation with regard to evaluation time and detection rates for hepatic and extrahepatic colorectal metastases in candidates for liver surgery. MATERIALS AND METHODS: In 20 patients with a history of colorectal carcinoma, two radiologists independently evaluated CT data sets. Focal hepatic lesions were characterized as benign or malignant by using a five-point scale. In each patient, soft-copy readouts and hard-copy printouts were compared for nonenhanced hepatic, contrast material-enhanced hepatic, and contrast-enhanced extrahepatic data sets. A stopwatch was used to document evaluation time. Ninety-two hepatic metastases and six extrahepatic metastatic recurrences were detected with the standard of reference--surgical, intraoperative ultrasonographic, and histologic findings. RESULTS: Both observers evaluated the contrast-enhanced hepatic data set significantly faster (P =.026 and.009) by using soft-copy readouts. The contrast-enhanced extrahepatic data set was also evaluated significantly faster (P =.010 and.006) with soft-copy readouts. Detection of hepatic and extrahepatic tumor with soft-copy readouts is not significantly superior to that with hard copies. Detection rates of hepatic metastases for nonenhanced and contrast-enhanced CT for both observers ranged from 50%-80% (46-74 of 92) for soft-copy readouts and 46%-75% (42-69 of 92) for hard copies. Interobserver agreement was highest for contrast-enhanced soft-copy readouts for hepatic metastases. CONCLUSION: Soft-copy readouts of contrast-enhanced CT data sets for the detection of hepatic metastases and extrahepatic metastatic recurrences were evaluated significantly faster than were hard copies, with at least equal sensitivity and with excellent interobserver agreement.     

Computed tomography of the ileocecal region

The CT scans in 25 patients without ileocecal pathology and 52 patients with ileocecal abnormalities were retrospectively reviewed. The ileocecal region was identified in 18/25 (72%) of patients without pathology. Thirty of 52 patients with ileocecal pathology had inflammatory disease: Crohn's (13), appendicitis (9), abscess (6), and typhlitis (2). CT was complementary to barium studies, demonstrating wall thickening, pericolonic inflammatory change, masses, fascial thickening, and fistulae. Twenty patients had malignancy: primary carcinoma (9), metastases (7), and lymphoma (4). In all patients with carcinoma a mass was identified. Pericolonic stranding represented tumor extension in 5/6 patients. Metastases were identified as extrinsic ileocecal masses in all 7 patients. Liver, mesenteric and omental metastases were present in 8/20 patients. In patients with lymphoma there was wall thickening and two had additional pericecal lymphadenopathy. In 2 patients with hypoalbuminemia, findings included: wall thickening, mesenteric, and subcutaneous edema.     

Contrast-enhanced CT colonography in recurrent colorectal carcinoma: feasibility of simultaneous evaluation for metastatic disease, local recurrence, and metachronous neoplasia in colorectal carcinoma.

OBJECTIVE: Contrast-enhanced CT colonography has the potential to detect local recurrence, metachronous disease, and distant metastases in patients with a history of invasive colorectal cancer. The purpose of our study was to determine whether colonic anastomoses prohibit adequate colonic distention on contrast-enhanced CT colonography and to estimate the performance of contrast-enhanced CT colonography in detecting recurrent colorectal carcinoma. MATERIALS AND METHODS: Fifty patients with a history of resected invasive colorectal carcinoma underwent contrast-enhanced CT colonography and colonoscopy. Colonic distention was graded for different colonic segments. Two radiologists evaluated for the presence of local recurrence, metachronous disease, and metastatic disease. Results were compared with colonoscopy, histology, and clinical follow-up. RESULTS: Most patients had adequate colonic inflation (37/50, 74%). Eleven of 13 patients with inadequate distention had collapse in the sigmoid colon, usually associated with ileocolic anastomoses. Contrast-enhanced CT colonography detected local recurrences with an accuracy of 94% (95% confidence interval, 83-99%). The accuracy of contrast-enhanced CT colonography for metachronous lesions greater than or equal to 1 cm was 92% (95% confidence interval, 80-98%), but there was only one such lesion, which was missed on initial colonoscopy. Stool, granulation tissue, and inflammation can mimic the CT appearance of local recurrence or metachronous disease and account for false-positive examinations. Contrast-enhanced CT colonography identified five patients with metastatic disease. CONCLUSION: Suboptimal sigmoid distention can be seen on contrast-enhanced CT colonography, predominantly in patients with right hemicolectomies. Contrast-enhanced CT colonography is a promising method for detecting local recurrence, metachronous disease, and distant metastases in patients with prior invasive colorectal carcinoma. The technique can also serve as a useful adjunct to colonoscopy by detecting local recurrences or metachronous disease that are endoscopically obscure or by serving as a full structural colonic examination when endoscopy is incomplete.     

Neck evaluation with barium-enhanced radiographs and CT scans after supraglottic subtotal laryngectomy

Supraglottic subtotal laryngectomy (SSL) is a radical, yet voice-conserving, surgical procedure commonly performed for carcinoma of the supraglottic larynx. The pharyngograms and computed tomographic (CT) scans of 35 patients obtained after SSL were evaluated retrospectively. These examinations reliably demonstrated the changes in anatomy caused by removal of the epiglottis, aryepiglottic folds, and false vocal cords. Fourteen patients had documented recurrence of cancer; five mucosal, nine extramucosal. Three of five macroscopic mucosal recurrences in the larynx/pharynx were detected on the barium pharyngograms; the two mucosal lesions not seen were in the base of the tongue and tonsillar fossa. CT enabled detection of five of five recurrences and was superior to pharyngography in demonstrating the soft-tissue extent of disease. CT findings mimicking recurrence were seen in two patients: one with diffuse histiocytic lymphoma; the second, with benign hyperkeratosis. Barium and CT examinations are useful adjuncts to the clinical examination in detecting recurrent squamous cell carcinoma in patients following SSL.     

Small bowel: preliminary comparison of capsule endoscopy with barium study and CT

PURPOSE: To retrospectively compare capsule endoscopic (CE) findings with findings at barium studies or computed tomography (CT) in patients without evidence of small-bowel stricture at barium examination. MATERIALS AND METHODS: Fifty-two patients underwent CE, and the majority (43 of 52) did so for obscure gastrointestinal bleeding. Forty-two (81%) of 52 patients underwent 36 small-bowel follow-through examinations; four, enteroclysis; and 19, contrast material-enhanced CT of the abdomen and pelvis within 6 months of CE (either before or after CE). Imaging results were retrospectively reviewed and compared with CE, standard endoscopic, and surgical results. Findings of any examinations between CE and imaging that were discrepant were retrospectively reviewed by a radiologist not blinded to CE results. Proportion of positive findings at CE was compared with proportion of positive findings at barium studies and CT in the same patients. Statistical significance was calculated with McNemar chi2 statistic. RESULTS: Barium examination findings were positive in one (3%) of 40 patients; CE findings were positive in 22 (55%) (P <.001). CT demonstrated small-bowel findings in four (21%) of 19 patients, but CE demonstrated findings in 12 (63%) of 19 patients (P =.02). The most common CE finding, angioectasia (n = 11), was not detected at any imaging study. More ulcers (n = 8) were detected with CE than with barium study (one of eight) and CT (three of six). At CE, three of five surgically confirmed masses (carcinoid, intussusception, lymphangioma) were identified, but two jejunal tumors were not detected in a patient with poor bowel preparation. At barium study, no masses (zero of five) were detected; at CT, one of four masses was detected. CONCLUSION: In patients without a small-bowel stricture at barium study, more small-bowel disease was found at CE when findings were retrospectively compared with barium examination and CT findings.     

CT evaluation of extrahepatic disease in patients with metastatic colorectal carcinoma receiving hepatic arterial chemotherapy

Computed tomography (CT) of the abdomen and pelvis in 88 patients with hepatic metastases from colorectal carcinoma undergoing hepatic arterial chemotherapy has been reviewed. Extrahepatic disease was present as determined by CT examination in 83 (94%). Tissue proof was available for 23 sites in 19 patients, with the most common sites being retroperitoneal lymph nodes (5), lung (3), abdominal wall (3), and peritoneum or mesentery (3). Clinical proof was obtained for 78 sites in 51 patients, the most common being lung (20), retroperitoneal lymph nodes (19), and porta hepatis lymph nodes (12). CT detection of extrahepatic disease is useful, since its presence has prognostic and therapeutic implications.     

Usefulness of CT colonography in the preoperative evaluation of patients with distal occlusive colorectal carcinoma

PURPOSE: To evaluate the role of preoperative virtual colonoscopy to study the proximal colon in patients with distal occlusive carcinomas, diagnosed by conventional colonoscopy. MATERIAL AND METHODS: We examined 19 patients aged 46 to 83 years (13 men and 6 women) with distal occlusive colorectal carcinomas diagnosed by conventional colonoscopy, who were preoperatively studied with virtual colonoscopy. Patients with acute bowel obstruction were excluded. Results were compared with the findings of preoperative conventional colonoscopy and barium enema examination, intraoperative colon palpation, histopathologic outcome, postoperative conventional colonoscopy and barium enema examination. RESULTS: Virtual colonoscopy identified all 19 distal occlusive colon carcinomas and 22 synchronous lesions, 2 cancers (prevalence 10,6%) and 20 polyps (prevalence 68,4%). Both synchronous cancers were confirmed intraoperatively by direct palpation. Postoperative conventional colonoscopy, which was performed in 18 patients, confirmed the presence of 15 polyps in 12 patients. Three subcentimeter polyps were removed during conventional colonoscopy and were missed at virtual colonoscopy. Two polyps shown by virtual colonoscopy were not found at conventional colonoscopy. Postoperative barium enema was performed in three patients and confirmed three polyps identified at virtual colonoscopy. Preoperative barium enema was performed in five patients and failed to adequately demonstrate the proximal colon. Virtual colonoscopy showed a sensitivity of 87% and a specificity of 75%. CONCLUSIONS: Virtual CT colonoscopy can be considered an important diagnostic technique to evaluate preoperatively the proximal colon in patients with distal occlusive carcinomas,as it gives better results than barium enema or conventional colonoscopy, as well as being well tolerated and less invasive.