Abstract
Introduction
MAVRIC-SL (MVSL), a multi-spectral magnetic resonance imaging (MRI) sequence [1] used for visualization of tissues near hip arthroplasty, can be accelerated by a short calibration scan [2], permitting an isotropic acquisition in a clinically feasible scan time. Decreasing the repetition time (TR) can further reduce scan time. This study evaluated the feasibility of acquiring isotropic MAVRIC-SL images (MVISO) and reduced TR isotropic MAVRIC-SL images (TRMVISO) of hip arthroplasties to elucidate the added clinical benefit of such acquisitions.
Methods
Following IRB approval, MVSL, MVISO and TRMVISO images were acquired for 93 hip arthroplasties (84 subjects). Images were reviewed by 2 radiologists to evaluate clinical and image quality features. Comparison of features between scanning sequences was assessed by mixed-effects ordinal logistic regression and odds ratios (OR). Inter/intra-rater agreement was determined using Gwet's agreement coefficient (AC).
Results
A calibration scan permitted acquisition of isotropic image sets in under 8 minutes. MVISO and TRMVISO had decreased blurring and improved visualization of the synovium and periprosthetic bone as compared to MVSL (p<0.001, Fig. 1). MVISO and TRMVISO improved image quality features over MVSL, OR range: 1 to 968. MVISO acquisitions also had better image quality, visualization of synovium and bone, lesion conspicuity, and decreased blurring than TRMVISO (p<0.032). Substantial to perfect (0.61 ≥ AC ≥ 1.0) agreement was found for 86% of factors evaluated by the 2 readers.
Conclusions
The isotropic acquisitions displayed clinically relevant features better than MVSL, with notable improvement of blurring and overall image quality. The TRMVISO altered the image contrast and contributed to poorer visualization of synovial reactions as compared to MVISO. The study demonstrated that isotropic MAVRIC scans are clinically feasible, and that MVISO scans added clinical value through improved visualization by reducing blurring.
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