Investigating age and regional effects on the relation between the incidence of heat-related ambulance transport and daily maximum temperature or WBGT.

BACKGROUND: Although age and regional climate are considered to have effects on the incidence ratio of heat-related illness, quantitative estimation of age or region on the effect of occurring temperature for heat stroke is limited. METHODS: By utilizing data on the number of daily heat-related ambulance transport (HAT) in each of three age groups (7-17, 18-64, 65 years old, or older) and 47 prefectures in Japan, and daily maximum temperature (DMT) or Wet Bulb Globe Temperature (DMW) of each prefecture for the summer season, the effects of age and region on heat-related illness were studied. Two-way ANOVA was used to analyze the significance of the effect of age and 10 regions in Japan on HAT. The population-weighted average of DMT or DMW measured at weather stations in each prefecture was used as DMT or DMW for each prefecture. DMT or DMW when HAT is one in 100,000 people (T1 and W1, respectively) was calculated for each age category and prefecture as an indicator of heat acclimatization. The relation between T1 or W1 and average DMT or DMW of each age category and prefecture were also analyzed. RESULTS: HAT of each age category and prefecture was plotted nearly on the exponential function of corresponding DMT or DMW. Average R2 of the regression function in 47 prefectures in terms of DMW was 0.86, 0.93, and 0.94 for juveniles, adults, and elderly, respectively. The largest regional difference of W1 in 47 prefectures was 4.5 and 4.8 °C for juveniles and adults, respectively between Hokkaido and Tokyo, 3.9 °C for elderly between Hokkaido and Okinawa. Estimated W1 and average DMT or DMW during the summer season for 47 prefectures was linearly related. Regarding age difference, the regression line showed that W1 of the prefecture for DMW at 30 °C of WBGT was 31.1 °C, 32.4 °C, and 29.8 °C for juveniles, adults, and elderly, respectively. CONCLUSIONS: Age and regional differences affected the incidence of HAT. Thus, it is recommended that public prevention measures for heat-related disorders take into consideration age and regional variability.

Multi-volume fusion imaging of MR ductography and MR mammography for patients with nipple discharge.

Because nipple discharge is caused by carcinoma as well as benign disease, identification of intraductal abnormalities with ductography is important. Ductography is an invasive mammographic examination in which contrast material is injected directly into the duct. Failure to cannulate or extravasation may occur. Ductography shows evidence of lesions, such as filling defects, duct obstruction, or wall irregularity, but it does not reveal the lesion itself. Furthermore, ductography produces a two-dimensional image, so it does not show the shape of the dilated duct or the precise location of the intraductal lesion in the breast. We applied three-dimensional (3D) heavily T2-weighted imaging with fat suppression of the breast to produce MR ductography. The dilated ducts are seen in 3D as tubular structures with high signal, and intraductal abnormalities are seen as signal defects. Furthermore, MR ductography can show an obstructed duct that cannot be seen on ductography. We also performed 3D breast MRI with the intravenous infusion of contrast material to show the lesion itself. Finally, we fused these 2 volume images into a single 3D fused image that not only shows the existence of intraductal abnormality, but reveals the shape, size, and extent of lesion, allowing us to understand easily the relationship between the ducts with dilation and any intraductal lesions in the breast. We herein introduce and describe this noninvasive method and discuss various factors related to its diagnostic use.