Value of sonography in monitoring the therapeutic response of mediastinal lymphoma: comparison with chest radiography and CT.

The aim of this retrospective study was to assess the diagnostic value of mediastinal sonography, compared with that of chest radiographs and CT, in the follow-up of patients with mediastinal lymphomas and in the prediction of clinical outcome. The sonograms, chest radiographs, and CT scans of 40 consecutive patients with Hodgkin (n = 29) and non-Hodgkin (n = 11) lymphoma obtained before and after completion of therapy were analyzed blindly and independently by three radiologists and compared with clinical outcome. Nine patients were treated with radiotherapy, 12 with chemotherapy, and 19 with combined therapy. Therapeutic response was assessed from all available clinical and biochemical findings as well as from the combined results of all imaging studies performed on further follow-up. The sonograms showed obvious changes in the size and echogenicity of the mediastinal lymphomas that corresponded closely with the response to therapy. Sonography showed complete regression of the lymphomas in 30 patients who had complete remission. In five patients with incomplete remission, sonographic diagnoses were correct. All lymph nodes, irrespective of size, detected with sonography after a phase of complete remission indicated recurrence (five patients). Sonographic findings corresponded with those of CT in 25 (81%) of 31 cases. Clinical outcome suggested that the sonographic findings were more reliable in the five cases in which CT and sonographic findings conflicted. Chest radiographs were inadequate for monitoring the response of mediastinal lymphomas to therapy; in 17 (43%) of 40 cases, a false impression was obtained of the extent and therapeutic response of mediastinal lymphomas. The results of this study indicate that sonography is clearly superior to chest radiographs and comparable to CT for monitoring patients with mediastinal lymphomas.