Effect of pulsatile flow during cardiopulmonary bypass on thyroid hormone metabolism.

Changes in thyroid hormone levels during and after cardiopulmonary bypass (CPB) are well documented. However, little is known about the effects of pulsatile flow during CPB on thyroid hormone metabolism. To examine the effect of flow pattern, a prospective study was carried out using 30 patients undergoing coronary artery bypass grafting. Fifteen patients had pulsatile flow during CPB and 15, nonpulsatile flow. Serum samples were obtained preoperatively, during bypass, and at 2 and 24 hours postoperatively. Thyroid-stimulating hormone, thyroxine (T4), triiodothyronine (T3), free T4, and free T3 levels were measured by radioimmunoassay. All measured hormone levels except free T4 and thyroid-stimulating hormone decreased after the initiation of CPB. There were no differences in preoperative values between the two groups. However, levels of T3 and free T3 during and after CPB showed a significant difference between the two groups, with a smaller decrease in patients in whom pulsatile flow was used during bypass (p < 0.05). Thyroxine, and thyroid-stimulating hormone free T4 values showed no difference between the two groups at any sampling time. These data provide support for the use of pulsatile flow during CPB to establish a more physiologic state and maintain better thyroid hormone metabolism.

Evaluation of palpable breast masses with 99Tcm-MIBI: a comparative study with mammography and ultrasonography.

We evaluated the feasibility of 99Tcm-methoxyisobutylisonitrile (MIBI) as a tumour localizing agent in patients with palpable breast masses in comparison with mammography and ultrasonography (US). Forty-one patients with palpable masses were studied. An additional 12 women with no palpable breast anomaly also underwent 99Tcm-MIBI breast study. Multiple views were obtained and semiquantitative evaluation was applied. Mammography and US revealed all of the malignant breast masses but differential diagnosis of fibroadenomas could not be achieved. Twenty-five of 27 breast carcinomas were detected using 99Tcm-MIBI scintigraphy. Two patients with invasive lobular carcinoma showed absent MIBI accumulation. Eight of 14 axillary lymph-node metastases showed positive uptake (57%). Twelve of 14 patients with pathologically proven benign breast lesions did not demonstrate any MIBI accumulation. Focal MIBI uptake could be observed in two fibroadenomas. The sensitivity and the specificity of semiquantitative MIBI analysis were 93 and 86%, respectively. Subjective grading offered no additional help in the further differentiation of malignant breast masses. There was no significant difference between histopathological types of breast carcinomas and uptake grades. Our results indicate that 99Tcm-MIBI scintigraphy may provide additional information in the differentiation of malignant pathologies from benign lesions in patients with palpable breast anomalies.