Validation of carotid arterial wall volume measurement by cardiovascular magnetic resonance

Purpose: To validate cardiovascular magnetic resonance (CMR) arterial wall volume measurement using whole arterial specimens ex vivo.

Materials and methods: Twenty cadaveric carotid arteries (from 10 patients) were fixed in formaldehyde and imaged with a clinical T1-weighted 2D CMR sequence and, for imaging validation, with a high-resolution 3D sequence. Histological validation was performed by sectioning the arteries and microscopically determining area and volume.

Results: Comparison between the clinical 2D CMR sequence and the 3D high-resolution validation sequence showed equivalent luminal volumes (889 vs. 880 mm(3); P = 0.54; R(2) = 0.99), and slightly higher 2D CMR arterial wall volumes (982 vs. 916 mm(3); +7%; P < 0.01; R(2) = 0.96) and adventitial volumes (1901 vs. 1826 mm(3); +4%; P < 0.01; R(2) = 0.99). Comparison between 2D CMR and microscopy, performed over a similar longitudinal extent of vessel, showed slightly higher 2D CMR volumes for the lumen (354 vs. 308 mm(3); +14%; P < 0.01; R(2) = 0.97), arterial wall (388 vs. 351 mm(3); +10%; P < 0.01; R(2) = 0.97) and total volumes (750 vs. 665 mm(3); +12%; P < 0.01; R(2) = 0.95).

Conclusion: The accuracy of the clinical 2D CMR vessel wall sequence for measuring carotid lumen, adventitial, and wall volumes is good against ex vivo measurements, with minor overestimation. This study validates carotid arterial wall quantification by CMR for atherosclerosis research.