CT findings for postsurgical blind pouch of small bowel.

OBJECTIVE: Our objective was to define the CT criteria for blind pouches formed after enteric anastomosis. CONCLUSION: Familiarity with the CT appearance of blind pouches avoids the mistaking of these entities for bowel obstruction or abscesses.

Suspected acute pulmonary embolism: evaluation with multi-detector row CT versus digital subtraction pulmonary arteriography.

PURPOSE: To determine diagnostic accuracy of four-channel multi-detector row computed tomography (CT) in emergency room and inpatient populations suspected of having acute pulmonary embolism (PE) who prospectively underwent both CT and pulmonary arteriography (PA). MATERIALS AND METHODS: Patients referred for PA to assess suspected PE were eligible. Institutional review board approval and written informed consent were obtained. All patients underwent CT and PA within a 48-hour period. For CT, 4 x 2.5-mm collimation was used. Three readers independently evaluated each study for PE presence. PE status, vessel level, and lobar location were determined by means of majority rule, and interobserver agreement (kappa) was calculated for PE status, as assessed with each modality. Sensitivity and specificity of CT were calculated by using PA as the reference standard. Two radiologists later reviewed false-positive CT studies. RESULTS: The study group comprised 93 patients (median age, 56 years; range, 19-88 years). Sensitivity, specificity, and accuracy of CT were 100%, 89%, and 91%, respectively. kappa values were 0.71 and 0.83 for CT and PA, respectively, and were not significantly different between modalities. At PA, 18 patients (19%) had PE at 50 vessel levels (five main and/or interlobar, 24 segmental, and 21 subsegmental), 17 (94%) of which had PE at multiple sites. At CT, 26 patients (28%) had PE at 71 vessel levels (24 main and/or interlobar, 33 segmental, and 14 subsegmental). Twenty patients (77%) had PE at multiple sites. Review of eight false-positive CT studies showed an appearance highly suggestive of acute PE in three patients, chronic PE in one, and no PE in three; one study was inconclusive. CT better demonstrated large-level vessel involvement (P < .01), while PA better demonstrated small-level vessel involvement (P < .01). CONCLUSION: Multi-detector row CT has an accuracy of 91% in the depiction of suspected acute PE when conventional PA is used as the reference standard.

Computed tomographic colonography (virtual colonoscopy): a multicenter comparison with standard colonoscopy for detection of colorectal neoplasia.

CONTEXT: Conventional colonoscopy is the best available method for detection of colorectal cancer; however, it is invasive and not without risk. Computed tomographic colonography (CTC), also known as virtual colonoscopy, has been reported to be reasonably accurate in the diagnosis of colorectal neoplasia in studies performed at expert centers. OBJECTIVE: To assess the accuracy of CTC in a large number of participants across multiple centers. DESIGN, SETTING, AND PARTICIPANTS: A nonrandomized, evaluator-blinded, noninferiority study design of 615 participants aged 50 years or older who were referred for routine, clinically indicated colonoscopy in 9 major hospital centers between April 17, 2000, and October 3, 2001. The CTC was performed by using multislice scanners immediately before standard colonoscopy; findings at colonoscopy were reported before and after segmental unblinding to the CTC results. MAIN OUTCOME MEASURES: The sensitivity and specificity of CTC and conventional colonoscopy in detecting participants with lesions sized at least 6 mm. Secondary outcomes included detection of all lesions, detection of advanced lesions, possible technical confounders, participant preferences, and evidence for increasing accuracy with experience. RESULTS: A total of 827 lesions were detected in 308 of 600 participants who underwent both procedures; 104 participants had lesions sized at least 6 mm. The sensitivity of CTC for detecting participants with 1 or more lesions sized at least 6 mm was 39.0% (95% confidence interval [CI], 29.6%-48.4%) and for lesions sized at least 10 mm, it was 55.0% (95% CI, 39.9%-70.0%). These results were significantly lower than those for conventional colonoscopy, with sensitivities of 99.0% (95% CI, 97.1%->99.9%) and 100%, respectively. A total of 496 participants were without any lesion sized at least 6 mm. The specificity of CTC and conventional colonoscopy for detecting participants without any lesion sized at least 6 mm was 90.5% (95% CI, 87.9%-93.1%) and 100%, respectively, and without lesions sized at least 10 mm, 96.0% (95% CI, 94.3%-97.6%) and 100%, respectively. Computed tomographic colonography missed 2 of 8 cancers. The accuracy of CTC varied considerably between centers and did not improve as the study progressed. Participants expressed no clear preference for either technique. CONCLUSIONS: Computed tomographic colonography by these methods is not yet ready for widespread clinical application. Techniques and training need to be improved.

Image-guided coaxial fine needle aspiration biopsy with a side-exiting guide.

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy and complication rates of a side-exiting coaxial needle system for fine needle aspiration (FNA) biopsies. METHOD: Between 1995 and 1998, 127 nonconsecutive biopsies were performed on 122 patients (74 males, 48 females). CT guidance was used in 111, ultrasound guidance was used in 14, and both were used in 2 biopsies. Patient history, biopsy site, needle performance, complications, and cytology results were recorded. RESULTS: Diagnostic rate and accuracy were 92.9 and 99.2%, respectively. There were minor complications from 14 biopsies, and all of them arose from chest biopsies: pneumothorax in 13 of 47 and hemoptysis in 1 of 47. There were no major complications. CONCLUSION: The side-exiting coaxial needle system is a safe and effective alternative to the conventional end-exiting coaxial needle system for performance of image-guided FNA biopsies.

High resolution detection of internal structure of renal calculi by helical computerized tomography.

PURPOSE: There is considerable interest in using radiological imaging to predict kidney stone fragility before patient treatment. Case series of shock wave lithotripsy show that shock wave lithotripsy is repeated and/or ancillary procedures are done to remove shock wave resistant stones in a significant number of cases. If the fragility of stones were predicted at diagnosis, unnecessary shock wave treatment would be avoided. However, plain radiography allows little discrimination of stone type and simple numerical analysis of computerized tomography (CT) images by measuring Hounsfield units has been shown to be limited in its ability to predict stone fragility. MATERIALS AND METHODS: Urinary stones of known composition were imaged by helical CT in vitro at various slice widths and the images were assessed using a range of window settings. RESULTS: Visualization of stone structure was greatly enhanced using bone windows and a narrow slice width. Surface structure, such as crystalline leaves of calcium oxalate dihydrate, and internal structure showing the heterogeneity of composition or cracks were detected. Stones of similar mineral composition differed dramatically in terms of CT visible structure. CONCLUSIONS: Using a narrow slice width and bone windows greatly improves the visualization of kidney stone structure on helical CT. These results open up new possibilities for determining the relationship of stone structure and fragility for shock wave lithotripsy.