MAVRIC selective (MAVRIC SL) uses frequency-selective excitation with multiple ranges of different frequency bands. Multiacquisition with variable resonance image combination (MAVRIC) and slice-encoding metal artifact correction (SEMAC) are two recently developed metal artifact reduction techniques that significantly reduce susceptibility artifacts near metallic hardware. Many imaging centers have only 3-T MR systems, creating increased demand for new metal artifact reduction techniques for 3-T MR scanners.
MRI has also been recognized as an appropriate assessment tool for patients with adverse local tissue reaction, otherwise known as aseptic lymphocytic vasculitis–associated lesions (ALVAL) or adverse reactions to metal debris in the setting of metal-on-metal (MOM) total hip arthroplasty (THA) however, these studies were conducted with only 1.5-T MR systems because the degree of susceptibility artifact increases at higher magnetic field strengths. Thanks to its superior soft-tissue contrast and metal artifact reduction, MRI has been found to be the most accurate imaging tool in the assessment of periprosthetic osteolysis, wear-induced synovitis, and periarticular neurovascular abnormalities in patients with symptomatic HA. Therefore, there has been a demand for imaging modalities that can provide an accurate postoperative assessment after HA. Over time, HAs can be affected by periprosthetic osteolysis and loosening as a result of wear-induced synovitis. In recent years there have been marked improvements in component design and the surgical technique of HA, but patients continue to have postoperative complications after hip replacement, which can require revision or implant removal. Approximately 1–3% of the older adult population (≥ 65 years) in the United States will undergo total HA at some point. Hip arthroplasty (HA) is one of the most commonly performed procedures in the aging population. Keywords: arthroplasty, hip, MR artifact, MRI
The MAVRIC SL sequence can significantly reduce metal artifact on 3-T MRI compared with the 2D FSE sequence and can increase diagnostic confidence of 3-T MRI in patients with total HA. Abnormal findings were significantly better shown on MAVRIC SL imaging compared with 2D FSE imaging ( p < 0.0001).ĬONCLUSION. The hip joint capsule and the muscle and tendon attachment sites of the obturator externus and iliopsoas muscles were better depicted with MAVRIC SL than 2D FSE ( p < 0.0125). The artifact score was also significantly decreased ( p < 0.0001) with MAVRIC SL compared with 2D FSE for both reviewers. The measured artifact area was significantly smaller ( p < 0.05) on MAVRIC SL than 2D FSE at both the level of hip (59.9% reduction with MAVRIC SL) and femur (31.3% reduction with MAVRIC SL). For qualitative analysis, two musculoskeletal radiologists independently compared paired 2D FSE and MAVRIC SL sets in terms of artifacts, depiction of anatomic detail, level of diagnostic confidence, and detection of abnormal findings. For quantitative analysis, the artifact area was measured at the level of the hip and femur. Paired image sets, composed of 13 coronal and 12 axial slices (total, 25 image sets), of the 21 hips were evaluated. Matched 2D FSE and MAVRIC SL images of 21 hips (19 patients with HA) were included in the study group. The objective of our study was to compare the multiacquisition variable-resonance image combination selective (MAVRIC SL) sequence with the 2D fast spin-echo (FSE) sequence for metal artifact reduction on 3-T MRI in patients with hip arthroplasty (HA).
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