[Ultrasound diagnosis of the vertebrobasilar circulation. I. Diagnosis of intracranial vertebrobasilar thromboses using conventional Doppler sonography].

To define the accuracy and the reliability of Doppler sonography carried out at the extracranial section of the vertebral artery for the detection of intracranially located significantly stenosing lesions of the vertebro-basilar trunk, 72 patients with brainstem disturbances combined with coma were examined prospectively. The Doppler findings were controlled by cerebral angiography. Doppler sonography turned out to be highly reliable for both the detection and the exclusion of high grade intracranial vertebrobasilar lesions. The parthognomonic finding was a pathologically altered time profile of extracranial flow with an abrupt deceleration during systole and discontinued flow or even reflux during diastole. This was called a "high resistance flow profile". However, if significant extracranial lesons are also present, the intracranial flow impedance may be masked. The limitations of Doppler sonography in this diagnostic field are discussed. Doppler sonography can provide the basis for a non-invasive differentiation of various types of cerebrovascular disease to define the optimal therapeutic strategy.