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DCTをベースとする高能率符号化を用いるディジタルVTRにおいて, 変速再生時の画質に関してシミュレーションによる検討を行った.本稿では, 検討結果の概要と良好な変速再生画像の実現を可能としたデータ処理手法について述べる.

The test bolus tracking (TBT) method is a new injection method of contrast medium that we developed. The TBT method is an injection technique that continuously performs the test bolus injection and the main bolus injection, such that the best acquisition of scan timing and the improvement of examination efficiency can be expected. We compared the TBT method and the test injection method by coronary CT angiography. The results demonstrated that the contrast enhancement of the coronary arteries was high and the variation of the CT value was also small in the TBT method. When the scan timing expected by the TI method and the TBT method were compared, it was different of two seconds or more by the case with 43%. However, the variation of CT value was small for the TBT method in these cases. Therefore, the TBT method is a very useful method for CCTA.

Objective Prevalence of hypertension was examined in a widely dispersed (45 110 km 2 ) representative group of Ladakhi in Northern India. The influence of hypoxic environment of wide-ranged altitude (2600–4900 m) and lifestyle change on hypertension was studied. Methods 2800 participants (age 20–94 years) were enrolled. Systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure of ≥90 mm Hg and/or taking current anti-hypertensive medicine was defined as hypertension. Height and weight for body mass index and SpO 2 were examined. The rural population comprised six subdivisions with a distinct altitude, dietary and occupational pattern. Participants in the urban area of Leh consist of two groups, that is, migrants settled in Leh from the Changthang nomadic area, and dwellers born in Leh. The prevalence of hypertension in the two groups was compared with that in the farmers and nomads in rural areas. The effects of ageing, hypoxia, dwelling at high altitude, obesity, modernised occupation, dwelling in an urban area, and rural-to-urban migration to hypertension were analysed by multiple logistic regression. Results The prevalence of hypertension was 37.0% in all participants and highest in migrants settled in Leh (48.3%), followed by dwellers born in Leh town (41.1%) compared with those in rural areas (33.5). The prevalence of hypertension in nomads (all: 27.7%, Tibetan/Ladakhi: 19.7/31.9%)) living at higher altitude (4000–4900 m) was relatively low. The associated factors with hypertension were ageing, overweight, dwelling at higher altitude, engagement in modernised sedentary occupations, dwelling in urban areas, and rural-to-urban migration. The effects of lifestyle change and dwelling at high altitude were independently associated with hypertension by multivariate analysis adjusted with confounding factors. Conclusions Socioeconomic and cultural factors play a big role with the effect of high altitude itself on high prevalence of hypertension in highlanders in Ladakh.

This paper describes a structured lighting method for the measurement of surface profiles of mat objects. In this kind of profilometry, a grating with binary transmittance distribution has been utilized. In these cases such a problem is known that an error is caused due to the non- sinusoidal transmittance of the grating. Another practical difficulty is in mechanical shifting of the grating. Here we propose to use a hybrid grating which consists of a conventional binary grating and a liquid crystal (LC) binary grating. Moire pattern produced by superposing these two binary gratings is available to overcome these problems. When two binary gratings are overlapped, the resultant moire pattern becomes closely sinusoidal in intensity distribution. And, when the LC grating pattern is moved, the projected pattern can be shifted arbitrarily in phase. Surface profiles of some samples are measured to show validity of hybrid grating projection and utility of the prototype system.

This paper describes a grating projection method using phase shifting technique for the measurement of surface profiles of three dimensional objects. In this kind of profilometry a grating with binary intensity distribution has been utilized in most of cases. And in these cases such problems are known as an error is caused due to the non-sinusoidal intensity distribution of the grating and another difficulty is also indicated that the period of the grating is required to be adjusted in accordance with the size and profile of the specimen. Here we propose to use a moire pattern which is produced by superposing two binary gratings. When two gratings are overlapped with an appropriate gap, the resultant moire pattern becomes closely sinusoidal in intensity distribution. Then, in the optical arrangement for profile measurement using a grating projection method, if one grating is rotated, the period of the pattern is varied arbitrarily. And if one or two of the gratings are moved in one direction, the formed moire pattern can be moved in one way to give necessary shifting of the phase. Surface profiles of some samples are measured to show validity of the moire pattern projection and utility of the prototype system.

Non-coronary incidental findings are not rare. Kirsch et al found 67% non-coronary abnormalities with coronary computed tomography angiography (CCTA). Radiologists are expected to identify the extracoronary, intra- and para-cardiac anatomical structures and distinguish them from pathologic processes in CCTA. We have reviewed 2000 CCTA studies done at our institution with 64-MDCT. This pictorial essay presents case studies of non-atherosclerotic cardiovascular findings to recognize cardiac anatomic structures and how to distinguish them from pathologic processes. Correct interpretation of benign, clinically insignificant findings is crucial to avoid unnecessary additional imaging tests.