Staging of malignant pleural mesothelioma: Comparison of CT and MR imaging

OBJECTIVE. This article compares the accuracy of CT with that of MR imaging in staging of malignant pleural mesothelioma, SUBJECTS AND METHODS. Ninety-five patients were enrolled in a prospective s taging protocol based on the International Mesothelioma Interest Group stag ing system. Sixty-five patients underwent CT and MR imaging and a surgical procedure (excluding percutaneous needle biopsy) to stage and resect the tu mor. Receiver operating characteristic analyses were performed. CT and MR s cans were interpreted independently by observers who were unaware of the re sults of the other imaging study; these imaging findings were compared with the results of surgery and pathologic examination, RESULTS. The areas under the receiver operating characteristic curves for e ight of 10 features revealed by imaging showed no statistically significant differences between CT and MR imaging. However, MR imaging was superior to CT in revealing invasion of the diaphragm (A(z) = .55 for CT versus .82 fo r MR imaging) and in revealing invasion of endothoracic fascia or solitary resectable foci of chest wall invasion (A(z) = .46 for CT; A(z) = .69 for M R imaging). Several anatomic regions could not be evaluated because positiv e findings at surgery were rare. CONCLUSION. CT and MR imaging are of nearly equivalent diagnostic accuracy in staging malignant pleural mesothelioma. MR imaging is superior to CT in revealing solitary foci of chest wall invasion and endothoracic fascia invo lvement and in showing diaphragmatic muscle invasion; however, this advanta ge does not affect surgical treatment. For cost reasons, CT should be consi dered the standard diagnostic study before therapy.