Ex vivo vessel wall thickness measurements of the human circle of Willis using 7T MRI.
BACKGROUND AND AIMS
MRI can detect intracranial vessel wall thickening before any luminal stenosis is present. Apart from representing a vessel wall lesion, wall thickening could also reflect normal (age-related) variations in vessel wall thickness present throughout the intracranial arterial vasculature. The aim of this study was to perform vessel wall thickness measurements of the major intracranial arteries in ex vivo circle of Willis (CoW) specimens using 7T MRI, to obtain more detailed information about wall thickness variations of the intracranial arteries.


METHODS
Fifteen human CoW specimens were scanned at 7T MRI with an ultrahigh-resolution T1-weighted sequence. Five specimens were used for validation of MRI measurements with histology and evaluation of inter-rater reliability and agreement. The other 10 specimens from patients with (n = 5) and without (n = 5) cerebrovascular disease were used for vessel wall thickness measurements over the entire length of the major arterial segments of the CoW using MRI only.


RESULTS
MRI measurements showed excellent agreement with histology. Mean wall thickness varied from 0.45 to 0.66 mm, minimum wall thickness from 0.31 to 0.42 mm, maximum wall thickness from 0.52 to 0.86 mm, and normalized wall index from 0.64 to 0.75. On average, vessel walls were thicker for symptomatic patients compared to asymptomatic patients.


CONCLUSIONS
High-resolution MRI enables accurate measurement of vessel wall thickness in ex vivo CoW specimens. Vessel wall thickness measurements over the entire length of segments showed considerable variation both within and between arterial segments of patients.
['Harteveld|Anita A|AA|', 'Denswil|Nerissa P|NP|', 'Van Hecke|Wim|W|', 'Kuijf|Hugo J|HJ|', 'Vink|Aryan|A|', 'Spliet|Wim G M|WGM|', 'Daemen|Mat J|MJ|', 'Luijten|Peter R|PR|', 'Zwanenburg|Jaco J M|JJM|', 'Hendrikse|Jeroen|J|', 'van der Kolk|Anja G|AG|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D002536:Cerebral Arteries D002941:Circle of Willis D005260:Female D006801:Humans D066298:In Vitro Techniques D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D009929:Organ Size D012189:Retrospective Studies
Vessel wall Wall thickness Atherosclerosis Brain Cerebral circulation Magnetic resonance imaging