Cerebral circulation in pregnant women was assessed by internal carotid (ICA) and middle cerebral artery (MCA) velocimetry with transcranial Doppler (TCD) . In normal pregnant women, mean velocity of MCA at 12-15 weeks gestation became faster by 12.3% than that in nonpregnant women. After that, the velocity decreased gradually to the term. At 36-40 weeks gestation, it was 16.4% slower than that in nonpregnant women. The results from serial study were concomitant with cross-sectional study. The MCA velocity was proved to be better correlated to regional cerebral blood flow in single photon emission CT and 133Xe inhalation study than ICA velocity. Although the causes of the change in pregnancy are far from clear, hypocapnea, metabolic acidosis, increment in cardiac output and sex steroids effects appear to affect cerebral hemodynamics. Postural change from left lateral position to supine one in late pregnant women affected cerebral circulation. We confirmed this using ICA velocimetry, that was, ICA velocity in the patients with supine hypotensive syndrome became slower than the control group. Increased incidence of cerebrovascular injuries has been noted in pregnancy. Hemorrhagic diseases such as subarachnoid hemorrhage from arteriovenous malformation are more often seen in 15-20 weeks gestation while ischemic and occlusive complications such as cerebral infarction tend to occur in the third trimester. Interestingly enough, our results were coincident with these facts, and may provide pathophysiological basis of management of pregnant patients with cerebrovascular complications.
Fetal intracranial arterial velocimetries were serially performed on 40 pregnant women with regular menstrual cycle, at 28-40 weeks of gestation, using color and pulsed Doppler ultrasound. The change in fetal intracranial arterial hemodynamics was based on the calculation of resistance index (RI) . RI in the anterior cerebral artery (ACA), middle cerebral artery (MCA) and posterior cerebral artery (PCA) showed significant changes with advancing gestational age, respectively. There was no signficant difference between the RI values in the ACA and MCA from 28 weeks to term. The RI in the PCA was significantly lower than that in the ACA and MCA, respectively, from 28 weeks to term (p<0.001) . This color and pulsed Doppler ultrasound assessment of fetal intracranial arterial blood flow provides a useful foundation for elucidating normal intracranial hemodynamics and wiil aid in avoiding misinterpretations of the different intracranial arteries.
Using Doppler color flow mapping (DCFM), neonatal cerebral hemodynamics were evaluated by comparing Doppler blood flow patterns between the right internal carotid (ICA) and middle cerebral arteries (MCA) . Transfontanellar right ICA as well as transcranial MCA blood flow patterns were obtained for 30 fullterm neonates in the first or second day after birth. The peak flow velocity (PFV), end-diastolic flow velocity (EDFV), mean flow velocity (MFV), the ratio of acceleration time to ejection time (AT/ET) as well as the time difference between the pre-ejection period (PEP) of the ascending aorta and that of the cerebral artery (ΔPEP) were measured. The PFV, EDFV as well as the MFV of MCA were relatively higher than those of ICA (p<0.01) . Also the ΔPEP of MCA was longer than that of ICA. However there was no difference in the AT/ET between ICA and MCA. We therefore consider that by using DCFM, it is possible to evaluate and compare the regional cerebral hemodynamics in neonates in assosiation with their systemic hemodynamics.
With the improvement of ultrasonography, we can easily detect congenital anomalies of the fetuses, particularlly the central nervous system disorder. Identification of such cases can be extremely helpful in clinical management. We have managed 20 cases of fetal central nervous system disorder in the last 8 years. There were 6 cases of holoprosencephaly, 2 cases of meningocele, 2 cases of meningomyelocele, 1 case of meningoencephalocele, 2 cases of Dandy-Walker cyst, 1 casee of agenesis of corpus callosum, 1 case of arachnoid cyst, 1 case of microcephaly, and 4 cases of anencephaly. In all these cases, the abnormalities were detected prenatally and 90 percent of cases were correctly diagnosed in primary diagnosis by ultrasonography. With the additional assestance of color flow mapping and MRI, we prenatally diagnosed and treated these cases. In our institute the cases of anen cephaly and holoprosencephaly with cyclopia were absolutely hopeless cases, and were terminated. We watched the other cases carefully. The one month survival rate of these cases, (excluding the 7 terminated cases) was 9/13. And their outcomes were as following: no handicap: 2; mild handicap: 2; moderate handicap: 2; severe handicap: 3. In addition, we present a pilot study of transabdominal head-compression test (changing MCA flow wave form analysis) in order to detect the fetal CNS disorders.
Fourteen cases of fetal dysraphism were analyzed in lights of neuroimagings and diagnostic problems. In cases of cranial dysraphic states, early diagnosis during the period oflegal termination was possibly made with clearly delineated morphology in ultrasonography (US) . Cephaloschisis, in one craniorachischisis and four anencephaly, was satisfactorily diagnosed in ultrasonographic configuration of the absent calvaria and high intensity shadow of exposed placode of MR TI weighted images. Intra and extra-cranial structures were properly evaluated in fetuses with cranium bifidum cysticum by ultrasonography. In spinal dysraphism, however, the primary spinal lesion was hardly evaluated ultrasonographically, unless the lesion is associated with a significant cystic mass. Prenatal neuroimagings of fetal dysraphism should be established along with US morphology evalution and other specific tools including plain X-rays, fetography. CT and MR may play significant roles depending upon the type of malformation.
A consecutive series of 24 patients with central nervous system anomalies were detected antenatally between December, 1987 and December 1989. The fourteen patients had undergone operative treatment immediately after birth. Ultrasound, computed tomography (CT) and magnetic resonance (MR) imaging was performed in order to evaluate the fetal central nervous system anomalies. The fetal ventricular system may be identifiable through use of these techniques. These rapidly deneloping imaging techni ques are particularly well-suited for fetal ventricular system identification. And MR imaging may also be a useful technique for examinatin of the fetal brain as well as prenatal ultrasound assessment and it may offer the potential for more detailed prenatal diagnosis.