PURPOSE: To prospectively investigate the diagnostic accuracy of and appearances at magnetic resonance (MR) imaging of patients clinically suspected to have intraperitoneal abscesses. MATERIALS AND METHODS: Sixty-seven consecutive patients underwent MR imaging for suspected intraperitoneal abscesses. MR images were prospectively interpreted for intraperitoneal abscesses; the results were correlated with surgical, histopathologic, and laboratory findings. RESULTS: MR imaging revealed 25 fluid collections consistent with intraperitoneal abscesses in 22 of 67 patients (33%). Of these collections, 22 were intraperitoneal abscesses; one, a giant sigmoid diverticulum; and two, sterile fluid collections. The latter two patients had been receiving antibiotic therapy. MR imaging allowed exclusion of intraperitoneal abscesses in 45 patients (67%). All collections demonstrated decreased signal intensity on T1-weighted images; on T2-weighted images, 13 collections demonstrated homogeneously increased signal intensity and 12 demonstrated heterogeneously increased signal intensity. The abscesses were best demonstrated on gadolinium-enhanced T1-weighted fat-suppressed images as well-defined fluid collections with peripheral rim enhancement. Sensitivity was 100%; specificity, 94% (95% confidence interval = 83%, 99%); positive predictive value, 88% (95% confidence interval = 69%, 97%); negative predictive value, 100%; and accuracy, 96% (95% confidence interval = 88%, 99%). CONCLUSION: MR imaging has high diagnostic accuracy in evaluation of acute intraperitoneal abscesses.
PURPOSE: To prospectively investigate the diagnostic accuracy of and appearances at magnetic resonance (MR) imaging of patients clinically suspected to have intraperitoneal abscesses. MATERIALS AND METHODS: Sixty-seven consecutive patients underwent MR imaging for suspected intraperitoneal abscesses. MR images were prospectively interpreted for intraperitoneal abscesses; the results were correlated with surgical, histopathologic, and laboratory findings. RESULTS: MR imaging revealed 25 fluid collections consistent with intraperitoneal abscesses in 22 of 67 patients (33%). Of these collections, 22 were intraperitoneal abscesses; one, a giant sigmoid diverticulum; and two, sterile fluid collections. The latter two patients had been receiving antibiotic therapy. MR imaging allowed exclusion of intraperitoneal abscesses in 45 patients (67%). All collections demonstrated decreased signal intensity on T1-weighted images; on T2-weighted images, 13 collections demonstrated homogeneously increased signal intensity and 12 demonstrated heterogeneously increased signal intensity. The abscesses were best demonstrated on gadolinium-enhanced T1-weighted fat-suppressed images as well-defined fluid collections with peripheral rim enhancement. Sensitivity was 100%; specificity, 94% (95% confidence interval = 83%, 99%); positive predictive value, 88% (95% confidence interval = 69%, 97%); negative predictive value, 100%; and accuracy, 96% (95% confidence interval = 88%, 99%). CONCLUSION: MR imaging has high diagnostic accuracy in evaluation of acute intraperitoneal abscesses.