Comparison of Magnetic Resonance Angiography Scans on 1.5, 3, and 7 Tesla Units: A Quantitative Study of 3‐Dimensional Cerebrovasculature

Abstract

Although multiple studies demonstrate benefits of high field imaging of cerebrovasculature, a detailed quantitative analysis of complete cerebrovascular system is unavailable. To compare quality of MR angiography (MRA) acquisitions at various field strengths, we used 3-dimensional (3D) geometric cerebrovascular models extracted from 1.5 T/3 T/7 T scans. The 3D cerebrovascular models were compared in volume, length, and number of branches. A relationship between the vascular length and volume was statistically derived. Acquisition performance was benchmarked against the maximum volume at infinitive length. The numbers of vessels discernible on 1.5 T/3 T/7 T are 138/363/907. 3T shows 3.3(1.9) and 7 T 1.2(9.1) times more arteries (veins) than 1.5 T. The vascular lengths and volumes at 1.5 T/3 T/7 T are 3.7/12.5/22.7 m and 15.8/26.6/28.0 cm(3). For arteries: 3T-1.5 T gain is very high in length, high in volume; 7 T-3T gain is medium in length, small in volume. For veins: 3 T-1.5 T gain is moderate in length, high in volume; 7 T-3T gain is very high in length, moderate in volume. 1.5 T shows merely half of vascular volume. At 3 T 6%, while at 7 T only 1% of vascular volume is missing. Our approach differs from standard approaches based on visual assessment and signal (contrast)-to-noise ratio. It also measures absolute acquisition performance, provides a unique length-volume relationship, and predicts length/volume for intermediate teslages.