COMPARISON OF CT AND MRI IN THE EVALUATION OF THERAPEUTIC RESPONSE INTHORACIC HODGKIN DISEASE

Current imaging modalities are accurate in establishing the diagnosis and extent of thoracic Hodgkin disease. After treatment, however, it i s extremely difficult to differentiate potential residual active neopl astic disease from scar tissue, or identify early recurrence. We evalu ated the contribution of MRI in the assessment of the response to trea tment of thoracic Hodgkin disease in the assumption that scar formatio n would be characterized by low signal intensity in all pulse sequence s, whereas active tumor should maintain a degree of high signal intens ity on T2-weighted images. In 47 occasions (23 patients) both CT and M RI were able to identify correctly active disease, but had low specifi city in confirming remission because of residual tissues masses. High signal intensity on T2-weighted MR images often persisted despite remi ssion, probably because of edema, necrosis, granulation or other facto rs. MRI was somewhat more specific than CT and may be quite valuable t o confirm remission in patients with residual masses that no longer ap pear hyperintense on T2 after treatment.