Nihon Igaku Hoshasen Gakkai zasshi. Nippon acta radiologica最新文献

Purpose: To verify the possible correlation between CT attenuation value and hemoglobin (Hb).

Materials and methods: CT attenuation was evaluated in 113 CT studies. Anemia was defined as an Hb level less than 14 g/dl in males and less than 12 g/dl in females. Hb was compared visually by grading (Grade 1: cardiac muscle density much higher than lumen, Grade 2: cardiac muscle density higher than lumen, Grade 3: cardiac muscle density equal to lumen), and with HU of CT attenuation on unpaired t-test (p<0.01). Correlations were calculated using the linear regression method.

Results: Hb of less than 6 g/dl was found to be Grade 1, while that over 12 g/dl was considered Grade 3 on visual grading. The attenuation numbers of subjects with anemia yielded low values, whereas those of normal subjects were higher. There were significant differences between subjects with anemia and normal subjects (p<0.01). HU versus hemoglobin showed a linear increase, with a correlation coefficient of 0.76.

Conclusions: This simple, readily available information may provide a valuable adjunct in the interpretation of CT examinations.

An investigation was conducted concerning long-term changes of patients' radiation exposure doses in medical procedures such as chest X-ray and CT scans. The result of the investigation compelled consideration of methods for reducing the exposure doses. While the exposure doses have decreased in chest X-ray compared with 30 years ago, they have remained unchanged in CT scan compared with 20 years ago. The following address possible causes of unchanged doses for CT scan: Measuring doses is difficult. Technology to reduce patients' doses has yet to be used effectively. It is important to take deterministic causes into consideration. More research and attention to the issue are needed.

The paper on the risk of radiation-related cancer following exposure to diagnostic X-ray, appeared in the issue of Jan 31, 2004 of the Lancet, and described an attributable risk estimate of 3.2% from the current medical exposure among the cancer incidences in Japan. While the fact that Japan is known as a country with the highest level of medical exposure, the quantification of radiation-related cancer risk have made quite an impact on medical society. The risk estimate based on the linear-non-threshold (LNT) dose response that remains unresolved scientifically need further research, but the radiation risk has been a useful tool not only for decision-making by risk-benefit analysis such as justification of medical use of radiation, but also for comparison with other risks. Recent radiation biology suggests that a bystander effect and adaptive response might modify the estimated cancer risk based on the LNT model at low doses. The risk from most diagnostic X-rays may be so small that excess cancer due to radiation can not be statistically detected. However, a diagnosis giving a relatively higher dose such as computer tomography in children should be carefully justified using a risk estimate. Raising awareness of low-dose cancer risk should involve not only understanding the process of risk estimation including data and assumption but also understanding there is indirect evidence for risk of lower level radiation exposure in medical procedures.

Purpose: According to recent studies, multidetector-row CT (MDCT) with a retrospective ECG-gating reconstruction algorithm shows a high correlation with coronary artery calcium score determined using electron-beam CT. Diabetes leads to many macrovascular complications, including coronary artery disease. The aim of this study was to evaluate risk factors for cardiac macroangiopathy in type 2 diabetes using MDCT.

Materials and methods: An observational cross-sectional study was performed in 90 patients with diabetes mellitus. Coronary calcium data was acquired by MDCT (SOMATOM Volume Zoom, Siemens AG, Medical Solutions, Germany). Physical examinations, laboratory data, glycemic control, and control of other risk factors were analyzed.

Results: The coronary artery calcium score increased with age. Multivariant analysis revealed that the coronary calcium score was closely correlated with electrocardiogram evaluation and control of hypertension.

Conclusions: Coronary artery calcium score as determined by MDCT can be used as a screening radiological examination for cardiac macroangiopathy in diabetes patients with electrocardiogram abnormality and hypertension.

As the incidence of breast cancer and deaths from breast cancer have been increasing, the Ministry of Public Welfare and Labor has been promoting breast cancer screening. Mammography screening began in fiscal year 2000 for those women 50 years of age or over, but attendance has not been increasing. This year (2004), the Ministry determined that mammography would be applicable to those 40 years of age or over and that screening with palpation alone would be abolished. To determine the effectiveness of the measures, mammography equipment, technologists, and readers were calculated. If the attendance were 50% of the 35,497 thousand women in this biennial screening, 40 persons would be examined by one apparatus per day, and, as there are 200 working days in a year, 1,109 apparatus would be needed. In the same way, if a technologist can examine 5,000 women, and a doctor can read 10,000 cases a year, both are apparently deficient in some prefectures. The standards of quality control for digital mammography have been determined by the Japan Radiological Society, and a "step phantom for mammography" has been developed. Qualitative evaluation of hard-copy clinical images has also started. All of the standards are presented in "Mammography Guidelines, Second Edition," published by Igakushoin, Tokyo, Japan, 2004.

We report a case of extrapontine myelinolysis (EPM) precipitated by correction of a hyper-osmolar state. A 7-year-old boy presented with disturbed consciousness. Serum BUN and Na level were 48 mg/dl and 196 mmol/L, respectively. T2-weighted images and FLAIR images of MRI visualized symmetrical bilateral high signal intensity areas in the external capsule and in the thalamus. In addition, the splenium of the corpus callosum showed high signal intensity. All these lesions showed high signal intensity on diffusion-weighted images. Extrapontine myelinolysis is precipitated not only by the rapid correction of a hypo-osmolar state but also by that of a hyper-osmolar state.

Objective: To compare the results of CT and barium enema examination in the diagnosis of peritoneal metastasis from gastric carcinoma.

Materials: Peritoneal metastases were pathologically confirmed in nine patients with gastric carcinoma who had had abdominal CT and barium enema examinations prior to surgery.

Methods and results: Five patients were reported to have colonic wall rigidity on preoperative barium enema examination. Review of the images indicated that six cases showed rigidity. On the other hand, no CT findings suggestive of peritoneal metastasis were reported in eight patients without ascites. No patients were indicated to have intraperitoneal nodules. For the retrospective evaluation, we changed the diagnostic procedure: the CT window setting was changed in wide window width (from 250 Hounsfield units (HU) to 400HU)and low window level (50-60HU to 0 HU), and reading mode was changed to a cine paging mode with a picture archiving and communication system (PACS) instead of hard-copy review. It followed that intraperitoneal nodules suggestive of peritoneal metastasis were detected in eight patients.

Conclusion: On conventional image reading, barium enema examination is of greater assistance than CT examination for detecting peritoneal metastasis from gastric carcinoma. However, the new CT reading method with PACS is more sensitive than barium enema examination for diagnosing peritoneal metastasis.