Fourier analysis of the cerebrovascular system

• Published in: Stroke (1970) Vol. 22; no. 6; pp. 721 - 726
• Main Authors: NJEMANZE, P. C, BECK, O. J, GOMEZ, C. R, HORENSTEIN, S
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.06.1991
• Subjects: Adult; Arteriovenous Malformations - physiopathology; Biological and medical sciences; Blood Flow Velocity; Cerebrovascular Circulation; Fourier Analysis; Humans; Hypertension - physiopathology; Ischemic Attack, Transient - physiopathology; Medical sciences; Neurology; Pulse; Reference Values; Vascular diseases and vascular malformations of the nervous system; Human; Hypertension; Regional blood flow; Intracranial; Nervous system diseases; Middle cerebral artery; Harmonic analysis; Cardiovascular disease; Mathematical analysis; Spasm; Hemodynamics; Arteriovenous malformation; Cerebrovascular disease
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/01.str.22.6.721

We performed Fourier analysis of the middle cerebral artery blood flow velocity waveform envelope in 14 normal subjects (group A) and 15 patients, of whom five had arteriovenous malformations (group B), five had cerebral vasospasm (group C), and five had arterial hypertension (group D). Measurements were obtained under conditions of normocapnia, hypercapnia, and hypocapnia. The Fourier coefficients measured in the first five harmonics of the Doppler waveforms of group A were used as the reference baseline and were compared with the coefficients found in the other three groups. Group B showed significantly lower Fourier coefficients, while groups C and D showed higher coefficients (p less than 0.05). The elevation of the Fourier coefficients occurred in an alternating pattern in group C and a decremental pattern in group D. This distinction was attributed to possible differences in the underlying pathophysiological processes. The degree of vascular distensibility of the cerebral arterioles, inferred from the shape of the Fourier analysis curves, was compared in all four groups. Vascular distensibility was characterized as abnormal in arteriovenous malformations, vasospasm, and arterial hypertension. Fourier coefficients may be better indicators of cerebrovascular abnormalities than mean blood flow velocity in hypertension and pulsatility index in arteriovenous malformations, vasospasm, and hypertension.