RESUMEN
BACKGROUND AND PURPOSE: The signal intensity of the thyroid in neonates is high on T1WI. It is affected by gestational and postnatal ages. However, the extent of the influence of these ages is unknown. This study investigated the relationship of signal intensities of the infant thyroid with postnatal and gestational ages and anterior pituitary using 3D gradient-echo T1WI. MATERIALS AND METHODS: This retrospective study included 183 T1-weighted images from 181 infants. Using a multiple linear regression analysis, we evaluated the effects of postnatal and gestational ages on the thyroid-muscle signal intensity ratio. The relationship between the thyroid and anterior pituitary signal intensities on T1WI and the age of the infants was evaluated. RESULTS: Multiple linear regression analysis showed that the thyroid signal intensity was affected negatively by postnatal age at examination and positively by gestational age at birth (P < .01 and P = .04, respectively). According to the standardized partial regression coefficients, the influence of postnatal age at examination was stronger than that of gestational age at birth (-0.72 and 0.13, respectively). The thyroid and anterior pituitary signal intensities reached constant values at 12 weeks' postnatal age, and the mean thyroid-anterior pituitary signal intensity ratios were almost 1 throughout the entire period. CONCLUSIONS: The signal intensity of the infant thyroid on T1WI was more strongly influenced by the postnatal age at examination than the gestational age at birth, and it was almost equal to that of the anterior pituitary.
Asunto(s)
Edad Gestacional , Imagen por Resonancia Magnética/métodos , Glándula Tiroides/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Lactante , Recién Nacido , Masculino , Hipófisis/diagnóstico por imagen , Estudios RetrospectivosRESUMEN
We investigated 90 autopsied cases with hematologic malignancy, including malignant lymphoma (ML), acute leukemia (AL), and adult T-cell leukemia (ATL) peculiar to our district, during the 10-year period 1982-1991 to determine the change in incidence of infection as a cause of death. We divided the cases into two groups representing the first half decade (1982-1986) and the second half decade (1987-1991) and compared the findings made in the two groups. Although infection was the major cause of death in those autopsied cases, the incidence of fatal infections decreased during the latter period. The incidence of fatal bacterial infections decreased, while fungal infections showed a relative increase. Pneumocystis carinii pneumonia and cytomegalovirus (CMV) infection occurred more frequently in patients with ATL than in those with ML or AL. Combined infection by more than three pathogens was observed in 2 cases of ATL. Our study revealed the characteristics of ATL specific to our district, and indicated the need to apply new strategies to prevent and treat fungal and viral infections in patients with hematologic malignancies.