Tadaatsu Nukada

A validation study on the reproducibility of transcranial doppler velocimetry

The transcranial Doppler method for the measurement of intracranial arterial blood flow velocity is a useful noninvasive technique with a number of applications. The present study validated the reproducibility of this method for repeated measurements of flow velocity in the middle cerebral and basilar arteries. Fifteen healthy volunteers were studied. Measurements were made twice by one examiner and once by another in a single day and again by the first examiner on another day. The reproducibility was evaluated by calculating the correlation coefficient (r) and the coefficient of variation (CV) of the difference between the values obtained from each pair of measurements. Although depending on the examiner, the time interval between the examinations and the vessels studied some differences were noted in the reproducibility, both the r (0.69-0.95) and CV (6.7%-19.5%) values in the whole study were good enough to warrant the applicability of this method for the repeated measurements of the intracranial arterial blood flow velocity in future studies.

To-and-Fro Movement and External Escape of Carotid Arterial Blood in Brain Death Cases. A Doppler Ultrasonic Study

In brain death cases who showed nonfilling phenomena in the internal carotid angiograms, the blood flow velocity patterns of the common carotid arteries were characterized by involvement of a single systolic peak and a marked reverse flow component which had never been observed in healthy subjects. The individuality of each blood flow velocity pattern in the common, internal and external carotid arteries was made clear by placing the transducer in contact with the respective artery in a certain case. The Doppler signal from the internal carotid artery involving a signal from a reverse flow was slightly detectable, even if the blood pressure was elevated by norepinephrine infusion and the external carotid artery was temporarily compressed. The blood flow velocity pattern of the external carotid artery was similar to the pattern of the common carotid artery. The peculiar flow pattern indicates that a brain death case has a to-and-fro movement in the internal carotid blood flow and an external carotid escape of common carotid arterial blood.

Diminished Reserve for Cerebral Vasomotor Response to L-Arginine in the Elderly: Evaluation by Transcranial Doppler Sonography

Background: Nitric oxide is pivotal in endothelially dependent vasodilatory regulation. An association of endothelial dysfunction with aging has been documented in the forearm and coronary vascular beds. However, the influence of aging in the human cerebral circulation, where regulation is particularly complex, is incompletely understood. Objective: We systematically administered L-arginine, a precursor of nitric oxide, to evaluate the influence of aging on nitric oxide-mediated cerebral vasomotor regulation. Methods: Among healthy volunteers, 20 older subjects (10 men, 10 women; age: 70.2 ± 2.8 years) and 22 younger subjects (10 men, 12 women; age: 28.8 ± 1.9 years) received intravenous infusions of L-arginine monochloride (500 mg/kg) over 30 min. Hemodynamic parameters were monitored continuously during and after infusion. The cerebral vasomotor response was estimated by transcranial Doppler sonography of the right middle cerebral artery. Results: Infusion of saline as a control brought little change in the mean blood pressure, heart rate or cerebral blood flow velocity in either group. On administration of L-arginine, cerebral blood flow velocity increased and mean blood pressure decreased. After completion of infusion, both parameters rapidly normalized. While reduction of mean blood pressure did not differ between older and younger groups, the cerebral circulation in the older group showed a blunted, smaller, and more easily saturated vasomotor response compared to the younger group, though both groups had similar baseline values. Conclusion: Our results indicate a diminished nitric oxide-mediated cerebral vasomotor response in aging subjects. Additionally, transcranial Doppler sonography can be used to reliably evaluate age-related changes in the physiologic responses of the human cerebral circulation.

Effect of transcranial Doppler intensity on successful recording in Japanese patients

The major limitation of transcranial Doppler sonography (TCD) is the failure to obtain data for all patients. The purpose of this study was to determine in detail the effect of increasing ultrasonic acoustic intensity on the rate of successful recording of intracranial blood velocity signals. The study was performed in 239 Japanese patients using a 2-MHz range-gated, pulsed-wave TCD. The middle cerebral artery flow signals were recorded at 76, 152, 228, 304, 380, 456 and 532 mW/cm2 and the results analyzed by age, gender and intensity. The rate of successful recording showed significant increase with the ultrasonic intensity in both genders (45.7% at 76 mW/cm2 vs. 81.1% at 532 mW/cm2 in males and 29.5% vs. 60.7% in females). However, recording was only successful in 54% of aged (50-89 gamma) female patients at the highest ultrasonic intensity used. It should be possible to significantly increase TCD usefulness in an aging Japanese population by further increasing TCD acoustic intensity within safety limitation.

Subclavian steal in Takayasu's arteritis. A hemodynamic study by means of ultrasonic Doppler flowmetry.

Blood flow in the vertebral artery and the upper extremity was studied in five cases of Takayasus arteritis with subclavian steal by use of ultrasonic Doppler flowmetry and finger plethysmography. The diagnosis of subclavian steal was made by observation of flow reversal in the vertebral artery on the subclavian steal side during grip exercise and, in addition, the vertebral flow change with brachial artery occlusion. The blood flow increase of both internal carotid and non-affected (non-subclavian steal side) vertebral arteries during a common carotid compression was almost normal in patients with Takayasus arteritis in this study. During carotid compression on the side of the subclavian steal, ipsilateral vertebral blood flow greatly decreased, and the amplitude of the ipsilateral finger plethysmogram decreased slightly or moderately. It is suggested that there are significantly important factors in suppressing symptoms of vertebrobasilar ischemia in these patients with Takayasus arteritis with subclavian steal. These factors are believed to be (1) good function of the circle of Willis, (2) good blood supply to the brain stem, and (3) collateral circulation to the distal subclavian artery not via the vertebral artery.

The hypotensive effect of prostaglandin E1 on hypertensive cases of various types.

Abstract Intravenous administration of 50 μg of prostaglandin E 1 (PGE 1 ) induced a fall of the blood pressure in the patients with hypertension. It included essential, renal, renovascular hypertension and hypertensions associated with Takayasus arteritis, primary aldosteronism, pheochromocytoma and anephric Kimmelstiel-Wilson syndrome. PGE 1 at dose of 50 μg had little effect on the blood pressure in normotensives. The pattern and the degree of lowering blood pressure were not specific for each type of hypertension. The antihypertensive effect of PGE 1 on essential hypertension was conspicuous in advanced cases. A clinical application of PGE 1 to manage severe hypertension was discussed.

Behcet's disease with sinus thrombosis and arteriovenous malformation in brain

SummaryA 55-year-old man suffered from Behcets disease with bilateral sigmoid sinus thrombosis and dural arteriovenous malformation has been studied clinically and pathologically. A possible causal relationship between Behcets disease and sigmoid sinus thrombosis is discussed.ZusammenfassungBei einem 55jährigen Patienten mit Behcetscher Krankheit fand sich sowohl eine Thrombose des Sinussigmoides wie auch eine arteriovenöse Mißbildung der Dura und des Gehirnes. Es wird über das Ergebnis der klinischen und pathologisch-anatomischen Untersuchung dieses Falles berichtet und die möglichen Beziehungen zwischen den obengenannten Besonderheiten des Falles untereinander kommentiert.

Interrelationships Among Regional Cerebral Blood Flow, Mean Transit Time, Vascular Volume and Cerebral Vascular Resistance

The simultaneous measurement of regional cerebral blood flow (rCBF), mean transit time (MTT), vascular volume (CVV) and cerebral vascular resistance (CVR) was performed in patients with cerebrovascular diseases. The measurement was made by a gamma-ray scintillation camera assisted by a minicomputer. A diffusible indicator of133Xe for CBF determination and a nondiffusible indicator of 99m Tc for MIT determination were used. The relation between rCBF and MTT showed a negative correlation in the nonfocal areas. The rCBF value in patients with normal brain was constant at high and low blood pressures. In patients with cerebral infarction there was a positive correlation between rCBF and mean arterial blood pressure. MTT had a negative correlation with mean arterial blood pressure in both patients with normal brain and those with cerebral infarction. In patients with normal brain a good negative correlation between CVV and CVR was found. In the nonfocal areas of cerebral infarction a high level of CVR was maintained regardless of the level of CVV.

The reproducibility of color Doppler duplex sonography in the measurement of renal arterial blood velocity.

In this study, the reproducibility of color Doppler duplex sonography for repeated measurements of renal blood flow was evaluated in 14 healthy subjects. We examined the reproducibility for different examiners and different time intervals between the examinations. Doppler frequency sonograms were analyzed with several parameters, and statistical evaluation was performed by calculating both the correlation coefficient (r) and coefficient of variation (CV). Peak systolic velocity (S), early diastolic velocity (D1) and mean velocity (MV) showed good reproducibility (r = 0.902-0.992, CV = 2.15-8.16%). On the other hand, end-diastolic velocity (D2), acceleration time (AT) and acceleration index (AI) showed poor reproducibility. We conclude that the reproducibility of this method is acceptable for repeated measurements of renal blood velocity, using suitable parameters S, D1 and MV.

Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part I. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and angiogram.

In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased Telocity of blood flow in both the internal carotid and rertebral arteries daring a contralateral carotid compression was compared with the angiographlc appearance of the drde of Willis. The flow vdodty was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the relationship between the increase of velocity of blood flow in the internal carotid artery and the anatomical variations of the circle of Willis, specifically the anterior cerebral and communicating arteries. The velocity of flow in the patients with an aplastic proximal portion of the anterior cerebral artery showed no increase. There were no differences in the increase of velocity of flow in the vertebral artery in patients with hypoplastk, normal and fetal posterior communicating arteries. It is considered that although anatomical variations of the drde vessels influence the cross-drculation via the drde of Willis, peripheral vascular factors distal to the drde also play an Important role in the quantity of cross-circulation through the drde. Stroke, Voll2, No4, 1981