MRI of Hip Arthroplasties: Comparison of Isotropic Multiacquisition Variable-Resonance Image Combination Selective (MAVRIC SL) Acquisitions With a Conventional MAVRIC SL Acquisition.
Academic Article
Overview
abstract
OBJECTIVE. The objective of our study was to compare the quality and diagnostic utility of the following three metal artifact reduction sequences in evaluating hip arthroplasties: conventional multiacquisition variable-resonance image combination selective (MAVRIC SL), isotropic MAVRIC SL, and reduced-TR isotropic MAVRIC SL. SUBJECTS AND METHODS. Ninety-three hip arthroplasties (85 total hip replacements and eight hip resurfacings [nine bilateral hips]) in 84 patients (38 men and 46 women; mean age ± SD, 69.1 ± 9.7 years old) were imaged and evaluated. A calibration scan determined the number of spectral bins needed for each implant, and isotropic and conventional MAVRIC SL images were acquired. Reduced-TR isotropic MAVRIC SL scans were acquired for 40 arthroplasties. Two board-certified radiologists blinded to MRI acquisition evaluated images for clinical and image quality features and compared images using a mixed-effects ordinal logistic regression model and odds ratios. Rater agreement was assessed with Gwet agreement coefficients. Scanning times were compared using mixed-effects linear regression. Significance was set at p < 0.05. RESULTS. Calibration scans decreased the number of bins needed (median, 12 bins; interquartile range, 10-16 bins). Isotropic MAVRIC SL (mean scanning time, 7 minutes 16 seconds; 95% CI, 7 minutes 7 seconds-7 minutes 25 seconds) acquisitions had the longest scanning time, and conventional (mean, 5 minutes 46 seconds; 95% CI, 5 minutes 37 seconds-5 minutes 55 seconds) and reduced-TR isotropic (5 minutes 28 seconds; 95% CI, 5 minutes 15 seconds-5 minutes 41 seconds) MAVRIC SL acquisitions had scanning times that were similar. Both isotropic and reduced-TR isotropic MAVRIC SL images showed decreased blurring and improved visualization of the synovium and periprosthetic bone compared with conventional MAVRIC SL images (p < 0.001). Isotropic MAVRIC SL acquisitions more effectively improved signal-to-noise ratio (SNR), visualization of the synovium and periprosthetic bone, and lesion conspicuity and decreased blurring compared with reduced-TR isotropic MAVRIC SL acquisitions (p < 0.032). CONCLUSION. Isotropic MAVRIC SL acquisitions improve SNR, conspicuity of lesions, and visualization of synovium and periprosthetic bone and decrease blurring compared with conventional MAVRIC SL acquisitions.
