CT AND MR-IMAGING EVALUATION OF CHEST-WALL DISORDERS

Computed tomography (CT) and magnetic resonance (MR) imaging have comp lementary roles in the evaluation of chest wall disorders, which inclu de mesenchymal tumors, primary and secondary malignancies, and inflamm atory and infectious diseases. Important anatomic regions of the chest wall to evaluate on axial images include the supraclavicular fossa, a xilla, and parasternal-internal mammary zone. For diagnosis of a suspe cted lipoma, CT is faster and less expensive; however, MR imaging may better delineate the extent of more invasive tumors if surgery is plan ned. MR imaging best depicts intramuscular neurofibromas and soft-tiss ue, intraspinal, and marrow involvement of neurogenic tumors, although CT more readily shows small calcifications and bone destruction. For diagnosis of lymphangioma, particularly when intravenous contrast mate rial cannot be given for CT, MR imaging is preferred. CT more accurate ly demonstrates cortical bone destruction from masses arising in the r ibs, but MR imaging is better for depicting infiltration of bone marro w and the extent of soft-tissue involvement. MR imaging displays Panco ast tumors and chest wall invasion from lung cancer better than CT bec ause of its multiplanar capability and depiction of subtle differences in soft-tissue contrast. Both CT and MR imaging are helpful in evalua ting infections, with CT being used to reveal bone destruction and to guide aspiration and drainage and MR imaging demonstrating soft-tissue involvement. The choice of technique, CT versus MR imaging, often dep ends on the specific clinical question to be addressed.