Malignant liver lesions: comparison of spiral CT arterial portography and MR imaging for diagnostic accuracy, cost, and effect on patient management.

We compared two imaging techniques, spiral CT arterial portography (CTAP) and MR imaging, for diagnostic accuracy, procedural cost, and effect on management of 26 patients referred for hepatic surgery for suspected limited malignant liver disease. CTAP and MR imaging were done within a 1-week period (19 within 24 hours); the results of the studies were interpreted prospectively by separate reviewers. Surgical data were evaluated in conjunction with imaging data in 10 patients. Lesion detection and segmental involvement were determined and sensitivity and specificity were calculated. Procedural cost was determined from hospital billing codes. Effect on patient management was determined by the referring oncologic surgeon. CTAP and MR imaging showed 185 and 176 true-positive malignant lesions, 15 and zero false-positive malignant lesions, zero and 18 true-negative malignant lesions, and 13 and 22 false-negative malignant lesions, respectively. CTAP and MR imaging showed 107 and 105 true-positive segments, 11 and zero false-positive segments, 80 and 91 true-negative segments, and four and six false-negative segments, respectively. There was a significant difference in specificity of segmental involvement between MR imaging (1.0 +/- 0) compared with CTAP (0.88 +/- 0.05), P = .03. Total procedural cost was $3,499 for CTAP and $1,224 for MR imaging. CTAP findings did not change patient management over MR imaging findings in any patient, whereas MR imaging findings resulted in a change in patient management over CTAP findings in seven patients (P = .015). The results of our study suggest that MR imaging has higher diagnostic accuracy and greater effect on patient management than CTAP does and is 64% less expensive.