胎児, 新生児中枢神経疾患の超音波診断

―新生児脳における選択的血統速度測定を中心に―

抄録

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 However, two-dimensional Doppler sonography, so-called color Doppler (CD) sonography, has superseded classical echosonography.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.