We measured simultaneously the flow velocity curves of the common carotid artery and the middle cerebral artery to evaluate the relationship between the systemic and cerebral circulations in the early neonatal period. Eligible for inclusion in this study were 20 healthy full-term neonates. Doppler ultrasound examinations were performed at 1, 2, 3, and 4 days after birth. The flow velocity curves of both arteries were recorded using a multi-channel Doppler system. Systolic maximal velocities and end-diastolic velocities were measured, and resistance indices (RIs) were calculated. The flow velocity of the middle cerebral artery increased during the first three days after birth, but that of the common carotid artery did not change. The RI of the middle cerebral artery remained constant, but that of the common carotid artery decreased on the third day after birth. These data suggest that the cerebral arteries might work as resistance vessels.
Transcranial Doppler sonography (TCD) is a useful method for investigating the hemodynamics of cerebral arteries. Phase-contrast (PC) MRA measures a vector quantity that contains information about blood flow direction and velocity. The purpose of this study was to evaluate the clinical usefulness of these modalities for investigating the hemodynamics of the ophthalmic artery (OA) and superior ophthalmic vein (Soy) . Between 1991 and 1996, ten patients with moyamoya disease and 6 patients with carotid-cavernous fistula (CCF) were evaluated using both methods. TCD was carried out through the orbital window. On the other hand, three-dimensional PC MRA and two-dimensional PC cine MRI were used with various velocity encoding gradient, and the flow direction in the OA and SOV was evaluated from the phase image. The results were as follows: (1) In moyamoya disease, the mean flow velocity (MFV) in the ophthalmic artery was relatively high, and reverse flow was seen in 3 of the 20 affected sides in both the TCD and PC MRA. (2) In CCF, the MFV in the SOV by TCD was elevated, although the level of the optimal velocity by PC MRA was relatively low. In conclusion, both TCD and PC MRA are clinically useful for evaluating the hemodynamics of the OA and SOV in moyamoya disease and CCF. Comprehensive evaluation using these two modalities should be done to understand the hemodynamics of these diseases.
We studied the relationship between carotid plaques and plasma endothelin-1 concentration (ET-1) in patients with essential hypertension. A total of 212 patients (83 males, 129 females, 36-84 yr, mean age 63 yr) with essential hypertension (WHO stage I-II), and 109 age-matched control subjects (35-79 yr, mean 61 yr) were enrolled in this study. Plaque (defined as intima-media thickness 50% thicker than neibour intima-media thickness) in the both side of common carotid artery and the both side of internal carotid artery were measured by B-mode ultrasonography. Plaques were classified into soft plaque (without calcification) and hard plaque (with calcification) . ET-1 was measured by enzyme immunoassay. ET-1 levels were significantly higher in hypertensive patients than in control subjects. The frequency of plaque in patients with high ET-1 levels (ET-1≥1.71 pg/ml) was signficantly higher than those with normal ET-1 levels (ET-1<1.71 pg/ml) . The frequency of soft plaque in patients with high ET-1 levels was signficantly higher than those with normal ET-1 levels. But there was no difference between the frequency of hard plaque in patients with high ET-1 levels and that with normal ET-1 levels. These results indicate that high ET-1 levels with essential hypertension may play a role in the progression of carotid plaque without calcification.
A rare case of duplicated spinal dural arteriovenous fistulae is reported. A 31-year-old woman suffering from congestive myelopathy was admitted. Spinal angiography demonstrated dural arteriovenous fistulae at the T10/11 intervertebral foramen. Surgical interruption of the fistulae was performed using micro-Doppler monitoring. Intraoperative micro-Doppler monitoring was performed on the dorsal redundant perimedullary vein, which showed an arterial spectrum. After ligation of the retrogradely irrigating radiculomedullary vein along the right T10 dorsal root, the arterial spectrum diminished, but was restored with time. Repeated temporary clipping under micro-Doppler monitoring disclosed a second dural arteriovenous fistula fed by the anterior spinal canal artery. The arterialized vein proximal to the coronal plexus was coagulated. After this procedure, the arterial spectrum disappeared on the dorsal perimedullary vein. Postoperatively, the patient's neurological deficits improved gradually. In this case, a second arteriovenous fistula located ventrally was found in addition to the usual radiculomeningeal arteriovenous fistula around the dorsal root. Intraoperative micro-Doppler monitoring was effective for detecting the residual arteriovenous shunting through the second arteriodural venous fistula. Microdoppler monitoring is an easily available and noninvasive monitoring technique. Use of this monitoring method will yield excellent results in surgery for spinal dural arteriovenous fistulae, and it is especially useful in rare cases such as duplicated arteriovenous fistulae.
The goal of acoustic neuroma surgery is to accomplish total removal of the tumor with functional preservation of the facial and cochlear nerves. A conventional ultrasonic aspirator is too large and heavy for performance of fine and delicate surgical maneuvers. We developed a compact and light-weight handpiece suitable for acoustic neuroma surgery. The handgrip is designed to fit the surgeon's hand, and is well balanced. Suction pressure can be controlled with a finger by closing or opening a hole set in the handpiece. The horn portion is exchangeable for one with a different tip diameter; the smallest diameter is 1.5 mm. This ultrasonic aspirator has been used in 48 acoustic neuroma operations. The aspirator enabled removal of a relatively hard tumor including one in the internal auditory canal quickly, without damage to the surrounding tissue. The maneuverability of the aspirator is similar to the conventional suction tube, in view of the suction-pressure control system and handgrip. Holding a regular suction tube in one hand and the ultrasonic aspirator in the other is the most convenient method for removing a tumor safely because the surgeon can always confirm the amount and nature of the residual tumor by touching the tumor with the regular suction tip.
Three-dimensional echo (3D-Echo) technology has been under development in the world for 10 years, and great progress has been made in both echographic equipment and personal computers. The principles of 3D-Echo have not changed, but now three-dimensional calculation has become practical. Current 3D-Echo systems have the following merits, and also demerits which must be improved. Merits 1. Wide area of view 2. Solid form 3. Feasibility of volume and weight measurements Demerits 1. No real-time display 2. No 2D image information 3D-Echo diagnostic ability and technology will be available in the near future. We need to develop performance, including highspecd (realtime), ease of operation, and various forms of measurement such as dynamic imaging, and also reduce the cost.