Ultrasound examination of the extracranial carotid and vertebral arteries has been used for many years to diagnose and manage patients with cerebrovascular disease. However, evaluation of the intracranial circulation has until now required angiography. Extracranial ultrasound examinations utilize probe frequencies ranging from 3 to 10 MHz. These frequencies are unable to penetrate bone sufficie...

Cranioplasty can improve neurological status in patients with skull bone defects. The mechanism of postoperative improvement in neurologic status might be increased cerebral blood flow (CBF) velocity due to elimination of the effects of atmospheric pressure. Between May 2001 and June 2002, 13 patients (8 men and 5 women; average age, 46 years; range, 21-65 years) were studied. Postoperative cha...

Transcranial duplex Doppler ultrasound was performed in 32 conscious dogs presenting ventriculomegaly detected in B-mode, obtaining measures of lateral ventricles and resistance parameters of main cerebral arteries before and after 30 days of clinical treatment. The animals were distributed divided in two groups: group 1, dogs that presented remission or decrease of the neurological signs of th...

Of the many causes of vertebrobasilar insufficiency (VBI), extrinsic compression of the vertebral artery (VA) is relatively uncommon. A syndrome of VBI caused by extrinsic compression of the VA secondary to head rotation has been termed positional vertebrobasilar ischemia. The authors present a case of transient VBI caused by herniation of a cervical disc. Transcranial Doppler ultrasonography w...

We used a combination of transcranial Doppler ultrasonography and single-photon emission computed tomography to noninvasively assess changes in the diameter of the middle cerebral artery induced by sublingual nitroglycerin in 10 healthy subjects. Nitroglycerin reduced mean blood flow velocities without concurrently changing regional cerebral blood flow in the perfusion territory of this vessel....

Previous studies demonstrated that cerebral blood flow (CBF) changes during dynamic exercise and a physiological basis for this observation may be explained by the tight control of CBF by arterial carbon dioxide tension (PaCO2). This study examined whether the steady state of the middle cerebral artery blood flow velocity (MCAVmean) and PaCO2 could be observed during constant work rate cycling ...

The pathophysiological changes of progressive neonatal hydrocephalus include: increased intracranial volume of cerebrospinal fluid, progressive dilatation of cerebral ventricles, decreased intracranial compliance, raised intracranial pressure, alteration of cerebral circulation and subsequent secondary brain tissue damage (decreased cerebral blood flow, hypoperfusion, ischaemia), alteration of ...

Greater occipital nerve block (GONB) is a common procedure to diagnose and treat patients with occipital neuralgia and to differentiate headaches of cervical origin from other types of headaches (1,2). Although a relatively safe method and easy to perform, the classical method of blind injection just medial to the palpated occipital artery at the level of the superior nuchal line is not target ...

BACKGROUND Transient ischemic attack (TIA) patients are at high vascular risk. We assessed the value of extracranial (ECD) and transcranial (TCD) Doppler and duplex ultrasonography to predict clinical outcome after TIA. METHODS 176 consecutive TIA patients admitted to the Stroke Unit were recruited in the study. All patients received diffusion-weighted imaging, standardized ECD and TCD. At a ...

Blood velocity in the middle cerebral artery was measured by transcranial Doppler ultrasonography in 15 patients suffering complete hemiplegia of less than 12 hours' duration, presumed due to cerebral ischemia. Among seven patients in whom blood velocity was greater than 30 cm/sec, five made complete or partial useful recovery of the involved hand and arm. Among eight patients in whom blood vel...