[PET-FDG in thyroid cancer with high thyroglobulin levels and negative 131-I scan. A case report]. / La PET-FDG en el cáncer de tiroides ante niveles altos de tiroglobulina y rastro 131-I negativo. A Propósito de un caso.

The value of whole body PET-FDG in the evaluation of metastases has been demonstrated in a wide variety of tumors. In this report, we present the case of a patient with antecedent of papillary thyroid carcinoma, who was operated twelve years ago, and submitted to an ablative dose of residual thyroid tissue through 131I, being the levels of thyroglobulin normals. After twelve years of evolution, the patient refers bag pain and respiratory trouble, appearing in the CT image suspicious of metastases in right pulmonary base. The levels of thyroglobulin were shown increased, being the 131I scan negative. A whole body PET-FDG study was performed in order to exclude metastases of his malignant process, showed multiple high FDG uptake focus in brain, cerebellum, neck, chest, lymphatic nodes and bone, suggestive of dedifferentiated disease These findings were confirmed subsequently in the clinic evolution. Therefore, whole-body PET-FDG is a complementary diagnostic technique for study patients with CDT (Thyroid Differentiated Carcinoma) with 131I scan negative and rising thyroglobulin levels.

SPECT study of regional cerebral perfusion in neuroleptic-resistant schizophrenic patients who responded or did not respond to clozapine.

OBJECTIVE: The purpose of this study was to find predictive criteria for response to clozapine. METHOD: Single photon emission computed tomography studies of cerebral perfusion were done in 24 treatment-resistant schizophrenic patients while they were taking typical neuroleptics and again after they had been treated with clozapine for 6 months. Perfusion ratios of the subjects categorized as responders or nonresponders to clozapine and of the subjects in the two treatment conditions were compared. The ratios with significant between-group differences were compared to those from a normal database. RESULTS: Before clozapine, while taking neuroleptics, subjects who became responders to clozapine showed higher thalamic, left basal ganglia, and right prefrontal perfusion. Nonresponders to clozapine had lower prefrontal perfusion and responders had higher subcortical perfusion than subjects in the normal database. The subcortical perfusion of the responders decreased when they received clozapine. CONCLUSIONS: The study of cerebral perfusion may contribute to the prediction of response to clozapine.