Comparación entre la ventriculografía radioisotópica en equilibrio con Tc99-albúmina-DTPA y SPECT gatillado cuantitativo (QGS) con Tc-99m-MIBI, para determinar la fracción de eyección del ventrículo izquierdo / Comparisson between radioisotopic ventriculography in balance with Tc99-albumine-DTPA and quantitative gated SPECT with Tc-99m-MIBI for determining the eject fraction of left ventricle

Se estudiaron 18 pacientes consecutivos (14 hombres y 4 mujeres, edad media 65 años) referidos para estudio GSPECT con Tc-99m MIBI después de esfuerzo ergométrico / reposo siguiendo protocolo de 1 dia. Las imágenes fueron sumadas y procesadas para la evaluación SPECT de perfusión miocardio (PM). GSPECT fue además procesado para calcular la FEVI(por ciento) usando el programa sincronizado cuantitativo (QGS). La VGRI en reposo se realizo 48-72 hrs. después de administrar con 925 MBq (25 mCi) de Tc-99m-ASH usando DTPA como agente quelante bifuncional. La ASH-DTPA fue preparada a temperatura ambiente, agregando a 2 ml de ASH al 2por ciento, 20 mg de DTPA y 1 mg de una solución estándar de cloruro estanoso y después el Tc-99m recién eluido del generador. La VGRI fue adquirida en posición anterior y en la mejor vista septal oblicua izquierda (OAI) durante 10 min. La FEVI (por ciento) en OAI fue computada manualmente dibujando regiones de interes (ROI) en la imagen de fin de diástole y sístole. En la VGRI también evaluamos visualmente la calidad de las imágenes cardiovasculares, y en la imagen de fin de diástole del ventriculograma en posición anterior, mediante ROI colocadas en el Ventrículo izquierdo (VI), hígado, pulmón y en el tercio superior del abdomen ( irradiación de fondo), se calculó la relación de actividad entre ellos. Resultados: A todos los pacientes se les realizó GSPECT después del ejercicio ergométrico máximo. Se utilizó QGS para calcular la FEVI(por ciento) tanto posejercicio en los pacientes con estudio SPECT de PM normal (n = 10) como en los con PM. anormal (n = 8) en quienes la FEVI(por ciento) fue estimada en reposo. No hubo diferencias significativas entre la FEVI (por ciento) con QGS y VGRI ( 55.5 ñ 13.4 vs 56.5 ñ 14.2 respectivamente). Ambos métodos se correlacionaron significativamente ( r = 0.78, p = 0.0001) y concordaron para identificar los pacientes con FEVI (por ciento) superior o inferior al 50 por ciento (índice kappa = 0.76). No se observaron diferencias estadísticamente significativas entre la FEVI(por ciento) calculada en la VGRI en reposo y QGS post ejercicio (n = 10) (62,5 ñ 8.3 vs 63 ñ 11.3), o la estimada reposo con ambos métodos. (n = 8) (VGRI 48.6 ñ 16.7, QGS 46.2 ñ 9.7 ), observándose correlación significativa entre la VGRI y QGS independientemente de que la FEVI(por ciento) fuera estimada después del ejercicio(r = 0.74, p =0.013) o en reposo(r = 0.75, p = 0.03)...

[Multiple endocrine neoplasia: a clinical model for applying molecular genetic techniques]. / Neoplasias endocrinas múltiples: un modelo clínico para aplicar técnicas de genética molecular.

Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The application of the techniques of molecular biology has made possible the identification of the genes causing MEN 1 and 2. The gene responsible for MEN 1 belongs to the family of tumor suppressor genes and encodes for a protein named MENIN whose function remains to be elucidated. The identification of mutant MEN 1 gene carriers who are at risk of developing this syndrome requires frequent biochemical screening for the development of endocrine tumors. MEN 2 is a consequence of mutations in the Ret proto-oncogene (c-Ret). This gene encodes for a tyrosine kinase receptor thought to play a role in the development of neural crest-derived tissue. Members of kindred with either MEN 2A or MEN 2B should be screened by direct DNA testing early in life for mutations in c-Ret. Those with the mutation should be advised to have thyroidectomy at five years of age in children with MEN 2A and earlier in children with MEN 2B. Some cases of sporadic MTC are actually MEN 2A or Familial MTC after c-Ret testing is done, therefore routine application of this test is recommended in all cases of apparent sporadic MTC.

[Treatment of diffuse hyperthyroid goiter with radioiodine: influence of propylthiouracil pretreatment]. / Tratamiento con radioyodo del bocio difuso hipertiroideo: influencia del pretratamiento con propiltiuracilo.

BACKGROUND: To stabilize Graves disease and deplete the preformed hormone, the use of antithyroid drugs prior 131I therapy has been suggested, specially in those patients with severe thyrotoxicosis and in the elderly. However, PTU may reduce the effectiveness of 131I. AIM: To study the effects of PTU pretreatment before 131I administration. SUBJETS AND METHODS: A retrospective analysis of the medical records of patients with Graves disease treated with 131I from 1989 to 1997 was made. Of 244 patients with adequate follow-up for at least 12 months after 131I treatment, 142 had not been pretreated and 102 had received PTU prior to 131I therapy. Pretreated patients were distributed according to the number of days that PTU was discontinued before receiving 131I, forming four groups (a = 5 d, b = 6-14 d, c = 15-30 d and d = 31-60 d). Radioiodine was delivered according to our protocol of 120 microCi per gram of thyroid tissue, as estimated by clinical examination. Therapy was considered successful when laboratory evidence of euthyroidism or hypothyroidism after one year of treatment was obtained and as a failure when undetectable TSH values persisted after 12 months of treatment with 131I. RESULTS: All groups were comparable as to age, gender, goiter size, and 24 h radioiodine uptake. Control of hyperthyroidism was achieved in 76% of the non pretreated group. A similar percentage was observed in groups (b), (c) and (d). However, the disease was controlled in only 50% of group (a) patients (p < 0.003). CONCLUSIONS: The therapeutic efficacy of 131I is significantly reduced when the PTU is stopped for only a few days prior to the use of radioiodine. We postulate that PTU has to be discontinued for at least 10 days before radioiodine administration.

Lingual thyroid: report of three cases.

Lingual thyroid is a rare developmental disorder and is more frequent in women. The pathogenesis is unclear but may be related to the presence of maternal blocking autoantibodies against the thyroid. Treatment of this disorder includes the use of levothyroxine in order to correct the hypothyroidism, which is very frequent and to induce the shrinkage of the gland. When symptoms of obstruction or bleeding appear, ablative therapy by means of surgery or radioiodine is warranted. We report three cases and discuss the approach to diagnosis and a strategy for management.