Atherosclerotic disease of the middle cerebral artery

Longitudinal monitoring of intracranial arterial stenoses with transcranial Doppler ultrasonography

The natural history of intracranial arterial stenoses remains relatively unknown. To monitor the progression of these lesions over time, the authors reviewed transcranial Doppler (TCD) laboratory reports at five hospitals for patients with angiographically documented intracranial arterial stenoses along the internal carotid artery distribution, and at least two TCD studies conducted more than 2 months apart. Twenty-two patients (19 men and 3 women; mean age, 64 years) with 29 stenoses were identified. The findings were compared to reproducibility data obtained from 11 age-matched control subjects with repeat TCD studies. During a mean follow-up period of 21 months, peak systolic flow velocities corresponding to the areas of stenosis increased in 9 arteries with lesions, and new collateral flow patterns, indicating further hemodynamic compromise distal to the lesions, developed in 2; one of the latter also had increased corresponding velocities. Thus, 10 (35%) arteries with lesions had TCD evidence of progression. Flow velocities remained the same in 13 (45%) stenotic vessels and dropped in 2 (7%). Findings were considered inconclusive for 4 lesions (14%). These findings suggest that intracranial arterial stenoses are dynamic lesions, and that they can evolve and cause further reductions of the arterial diameters after relatively short periods of time. TCD can noninvasively detect their hemodynamic effects.

Noninvasive detection of occlusive disease of the carotid siphon and middle cerebral artery

Recently, transcranial Doppler sonography has been introduced into clinical practice for noninvasive investigation of the large intracranial arteries. To determine its accuracy for detection of stenosing or occluding lesions, 133 consecutive patients were studied by both transcranial Doppler sonography and selective cerebral arteriography. Statistical analysis of findings was done separately for various arterial segments. High values for sensitivity and specificity were found for detecting obstruction of the carotid siphon and main stem of the middle cerebral artery. Diagnostic reliability of transcranial Doppler sonography was also confirmed by the calculation of a chance-corrected measure of agreement (kappa), which was close to + 1 in all subanalyses. Transcranial Doppler sonography seems to be a valuable tool for noninvasive detection of intracranial lesions of the middle cerebral artery and carotid siphon.

Middle cerebral artery pial territory infarcts: a study of the Lausanne Stroke Registry

Using a standard protocol (Doppler ultrasonography, electrocardiography, brain computed tomography, and in selected cases angiography, echocardiography, and Holter monitoring) we studied the clinical characteristics and etiological factors in 380 patients with first stroke who had a corresponding infarct limited to the territory of the pial branches of the middle cerebral artery (MCA) on computed tomography. The presumed cause of infarction was large-artery disease (greater than or equal to 50% carotid artery or MCA stenosis or occlusion) in one-third of the patients and cardioembolism in one-fourth of the patients. Half of 230 patients undergoing angiography showed evidence for distal occlusions suggesting artery-to-artery or cardiac emboli. Severe heart disease and potential cardiac sources of embolism were more common in patients with infarcts in the territory of the posterior (inferior) division of MCA than in patients with infarcts in the territory of the anterior (superior) division of MCA. Persisting functional disability on discharge was also more severe in patients with the former than in patients with the latter. The neurological picture was polymorphous and it could sometimes even be misleading, as in some patients with a classical lacunar syndrome or with aphasia and unexpected sparing of speech areas. However, a few clinical syndromes apparently specific for involvement of a single MCA branch could be delineated, and in some instances they were highly predictive of embolism from heart or proximal artery.