著者

古幡 博

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.12, no.1, pp.31-35, 1999-02-28 (Released:2010-10-14)

参考文献数

5

被引用文献数

2 1

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From the viewpoint of safety, it is necessary for the diagnostic ultrasonic equipment used in clinical practice to satisfy the FDA 510 (k) requirement track III. The new requirement requires medical doctors and staff to have a greater understanding of ultrasonic bioeffects as indicated by the mechanical index (MI) and the thermal index (TI), on the real-time display of recently developed diagnostic ultrasonic devices.This article describes the significance of MI and TI and the variables in clinical use. Also it is noted that the ultrasonic examiner should uphold the principle of ALARA (as low as reasonably achievable) in clinical use.

著者

佐藤 隆一 藤本 司 向山 正孝 大滝 博和 佐藤 知樹

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.13, no.4, pp.175-178, 2000-11-30 (Released:2010-10-14)

参考文献数

16

被引用文献数

2 2

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Cerebral blood flow changes during and after indirect moxibustion stimulation at the acupuncture point HO-KU (L-14), which is located between the thumb and index finger, were measured by transcranial Doppler ultrasound (TCD) . The mean blood flow velocities (Vm) of the right middle cerebral artery (MCA) in 10 normal subjects were measured continuously during and until 15 minutes after the stimulation. The Vm showed 2 peaks, at 1 minute after and 7 minutes after the stimulation. The extent of change in flow velocity was 23% at the first elevation and 20 - 26% at the second elevation. The second elevation of the flow velocity continued until 15 minutes after the stimulation. The heart rate increased at the first elevation and then returned to its previous level, but did not change at the second elevation. To evaluate vascular reactivity, a hyperventilation test was done before and after the examination ; it showed normal vascular reactivity at both points. The second elevation seemed to be induced by the effect of moxibustion. Vascular reactivity remained normal and no significant vascular diameter changes seemed to occur. From our results, a significant increase of cerebral blood flow is induced by indirect moxibustion stimulation.

著者

飯沼 一浩

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.8, no.1, pp.7-10, 1995-02-28 (Released:2010-10-14)

被引用文献数

1

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Accuracy and limitations of medical ultrasound are described in terms of several kinds of resolution, such as temporal, spatial, contrast and velocity resolution.Ultrasound speed of about 1500 m/s in human soft tissue, limits the number of frames per second, the viewing area and the scanning line density. There are trade-offs among these parameters. In color Doppler flow imaging, frame rate limitation is much more severe.Three kinds of spatial resolutions are defined as the range resolution, the lateral resolution and the slice width. A simple and practical drawing method for ultrasound beam width representing the lateral resolution is shown for non-focusing and focusing transducers. Upper and lower limitations of Doppler blood velocity measurements are described.

著者

半田 伸夫 岡崎 裕 伊藤 泰司 湯浅 義人 杉谷 義憲

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.13, no.4, pp.170-174, 2000-11-30 (Released:2010-10-14)

参考文献数

21

被引用文献数

5 3

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The purpose of the study was to investigate the association between Ischemic stroke and the ultrasonographic (US) characterization of carotid plaque on the basis of our original work and of a review of the literature.Carotid plaque is known to be a reliable marker of Ischemic stroke and systemic atherosclerosis. There is much evidence from secondary prevention trials to indicate a direct relationship between the surface and internal US characterization of carotid plaque and stroke. Moreover, in the primary prevention of stroke, the Cardiovascular Health Study showed that the risk of incident stroke was associated with two US features, hypoechoic internal carotid arterial plaque and an estimated internal carotid arterial stenosis of 50%-100%, in asymptomatic adults aged 65 years. However, many studies that have compared the morphologic features of carotid plaque as revealed by both US studies and histology have shown a relatively low rate of detection of important features such as intraplaque hemorrhage. Furthermore, although severe carotid stenosis is associated with a higher risk of stroke events, the power of US to predict such events is limited by low incidence rates and low rate of progression.We conclude that US plaque characterization should be used together with other risk factors in prospective natural history studies that aim to identify a subgroup of patients at high risk of stroke.

著者

市橋 光

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.13, no.1, pp.20-26, 2000-02-29 (Released:2010-10-14)

参考文献数

11

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Echoencephalography is very useful for the examination of the fetus and newborns, because it is easy to perform repeatedly at the beside, it is noninvasive, and it represents a real-time examination. A fetus is usually observed through the mother's body. To evaluate the neonatal brain, the transducer is routinely placed over the fontanelle. In this review article, the anatomy of the brain as visualized using echoencephalography, and the standard echoencephalography planes used are explained, and then some abnormal cases are shown. Finally, the detection of the brain circulation is discussed.

著者

林 隆 市山 高志 武田 香苗

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.13, no.1, pp.27-35, 2000-02-29 (Released:2010-10-14)

参考文献数

20

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Doppler sonography is a convenient and useful procedure for evaluating intracranial lesions and hemodynamics, especially in the fetus and neonate. Initially B-mode ultrasonic images were used as the main procedure for investigating intracranial lesions. However, two-dimensional Doppler sonography, so-called color Doppler (CD) sonography, has superseded classical echosonography. It is possible with CD to visualize the intracranial arteries and veins in real time. In addition, the pulsed Doppler system (PD) in combination with CD, can be used to measure selectively the flow velocity at any point in the CD-visualized vessels. PD combined with CD could represent the selective flow condition at the intracranial main vessels, the anterior cerebral artery, basilar artery, middle cerebral artery and internal cerebral vein. But the flow conditions in these main arteries may not reflect the peripheral hemodynamics. Recently we used power flow Doppler imaging (PF) to show vessels that have low flow and small caliber. Now we are able to visualize the lenticulostriate artery (LSA), which perforates the branches of the middle cerebral artery, and have demonstrated the steady flow conditions of intracranial peripheral circulation. Three-dimensional reconstruction of PF images may provide a new quantitative and qualitative method of evaluating intracranial circulation. Selective echoangiography should clarify the mystery that surrounds brain circulation in perinatal period.

著者

明石 恵司 近藤 秀樹 槙永 剛一 森岡 千佳子 松村 喜志雄 越智 直哉 古河 辰之 鄭 庸勝 谷口 典男 田中 重実 金子 仁郎 西村 健

出版者

The Japan Academy of Neurosonology

雑誌

Neurosonology:神経超音波医学 (ISSN:0917074X)

巻号頁・発行日

vol.9, no.2, pp.33-37, 1996-05-31 (Released:2010-10-14)

参考文献数

4

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This study was performed to examine the effects of mental arithmetic (MA) on cerebral blood flow (CBF) . We recorded the blood flow velocity before, during and after mental arithmetic in the bilateral internal carotid arteries (ICA) and vertebral arteries (VA) simultaneously and continuously in nine healthy males (25.8±7.2 y.o.) . The subjects performed MA for 30-60 seconds. The mean values of blood flow velocity (BFV) were calculated for each pulse using an FFT-analyzer.We observed BFV in 24 ICAs and 9 VAs in all of the 9 subjects. During MA in comparison with the period before MA, BFV in the 10 of ICAs and the 3 of VAs increased significantly, however BFV in the other 3 of ICAs decreased significantly and the rest 11 of ICAs was unchanged. The number of increases was significantly higher than that of decreases and no changes. After MA compared with the period during MA, BFV in the 3 ICAs and the 3 VAs decreased significantly, however BFV in one ICA increased significantly and the rest of 20 ICAs was unchanged. Also the blood pressure and heart rate were unchanged during MA.In summary, our study identified and documented statistically significant changes in cerebral blood flow velocity during MA. And it was suggested that some other factors, such as mental state, have influence on cerebral blood flow velocity during MA.