Valores normales de captación de 131Yodo de 2 y 24 horas / Normal 131Iodine uptake values at 2 ano 24 hours

Background: Radiolabeled iodine uptake is a useful tool in the study of thyroid diseases. Aim: To obtain normal values for 131 Iodine thyroid uptake in healthy volunteers. Material and methods: A total of 105 subjects were included (52 males and 53 females), with a mean age of 45 years (range: 20 to 68, evenly distributed in decades). A questionnaire was applied and a clinical examination was performed to rule out endocrine diseases. Serum TSH and anti-thyroperoxidase antibodies were also measured. The oral 131I dose was 5-10 fiCi, and a Thyrad equipment was used for measurements at 2 and 24 h. Results: Mean global iodine uptake was 5.5 percent±1.8 percent (range: 2.3-12.0) at 2 h and 16.2±4.8 percent (range: 6.5-30.1) at 24 h. The values at 2 h among women and men were 6.0±1.8 and 4.9±1.6 percent, respectively, (p <0.02). At 24 h, the figures were 17.3±4.5 and 15.0±4.9 percent, respectively (p =0.01). Compared to their younger counterparts, radioactive iodine uptake was lower among volunteers older than 40 years, at 2 h (5.0±1.7 and 6.0±1.8, respectively, p <0.02) and at 24 h (14.9±4.4 and 17.6±4.9 percent, respectively, p <0.01). Conclusions: Normal thyroid uptake values in adults are influenced bygender and age. Normal thyroid iodine uptake values are slightly higher in females. Iodine thyroid uptake values decrease slightly in subjects aged more than 40years.

Utilidad clínica de la fusión SPECT/CT con marcadores externos en patología oncológica / Fusion of SPECT with computed tomography or magnetic resonance for the interpretation of abnormal tracer uptake

Background: Interpretation of abnormal foci with high tracer uptake may require morphological correlation. Fusion of functional images obtained by single photon emission computed tomography (SPECT) and anatomical images obtained by computed tomography (CT) or magnetic resonance (RM) allows an integrated comprehension of complementary information. Aim To demonstrate that SPECT/CT fusion with external markers is useful in clinical practice to clarify the location and pathological meaning of questionable foci. Material and methods: Thirty four pairs of images from separate equipments (31 SPECT/CT and 3 SPECT/RM) pertaining to 29 patients, were fused. Fifty one foci of abnormal tracer uptake of uncertain pathological meaning were analyzed. These were classified before and after the fusion as probably malignant or probably benign. Results: Seventy percent of patients had a differentiated thyroid carcinoma. The fusion localized 100 percent of foci. Nine percent had a normal and 26 percent an abnormal anatomy. Before fusion 82 percent of foci were classified as potentially malignant. This figure changed to 59 percent after the fusion (p <0.01). Therefore the suspicion of malignancy was presumptively confirmed in 72 percent of foci and fusion results would have reached a 27 percent of incremental diagnostic value in 14 cases that changed of category (11 with differentiated thyroid carcinoma, one with colorectal cancer, one with a nasalEwingsarcoma and one with a brain tumor). Conclusions: The fusion of SPECT and CT is useful in selected patients, specially those with differentiated thyroid carcinoma. The fusion of SPECT and RM is also feasible.

Tiroides y depresión: enfoque terapéutico actual y bases moleculares / Thyroid and depression: actually and therapeutic approach and molecular basis

Depression is a serious and high-priority public health problem. In Chilean population, prevalence ranges from 5 to 27,3 percent. Therapy is based mainly in the use of selective serotonin reuptake inhibitors (SSRIs). Combination of thyroid hormone, sodium liothyronine, associated to traditional antidepressants to improve or accelerate therapeutic response is currently accepted. The use of this combination is based on hypothalamus-hypophysis-thyroid axis (HHT) alterations and on the peripheral conversion to active hormone, the triiodothyronine (T3), by type 2 and 3deiodinases (D2 and D3). Subtle changes in enzyme activity could have a strong impact in T3 brain availability. In major depression as high as a 25 percent of altered responses of HHT axis to the TRH stimulus may be observed. Certain polymorphisms of the D2 gene could be associated to enzyme activity changes. Isotopic studies are able to assess brain flow in diverse conditions, like global or specific regional perfusion variations in patients with mild hypothyroidism, pre and post T4 or SSRIs therapy in depressive patients.

Tromboembolismo pulmonar en lactante menor, portadora de enfermedad de Hirschsprung: caso clínico / Pulmonary thromboembolism in children with Hirschsprung disease: clinical case

Se presenta el caso de una lactante con enfermedad de Hirschsprung que requirió alimentación parenteral permanente y que presentó complicaciones de las vías venosas centrales incluyendo trombosis, septicemia y tromboembolismo pulmonar. El diagnóstico de las complicaciones trombóticas mediante Doppler y cintigrafía de ventilación perfusión permitió un tratamiento oportuno y seguimiento adecuado.