Evaluation of pleural disease using MR and CT - With special reference to malignant pleural mesothelioma

Purpose: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease. Material and Methods: Thirty-four patients (18 pleural mesotheliomas, 9 oth er malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Com parisons were made between the diagnostic groups and the imaging methods. Results: The abnormalities commonly found in malignant disease, but signifi cantly less frequently in benign pleural disease, were focal thickening and enhancement of interlobar fissures. In mesothelioma, enhancement of interl obar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignanc ies and MR was the most sensitive method. In other malignancies, invasion o f bony structures was a more common finding and was also better shown by MR . The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences. Conclusion: MR, especially the CET1fs sequence in three planes, gave more i nformation than enhanced CT. Focal thickening and enhancement of interlobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other ple ural diseases.