Biochemical MRI With dGEMRIC Corresponds to 3D-CT Based Impingement Location for Detection of Acetabular Cartilage Damage in FAI Patients

Abstract

Background: Anterior femoroacetabular impingement (FAI) is associated with labral tears and acetabular cartilage damage in athletic and young patients. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is an imaging method for detecting early damage to cartilage. Purpose: We evaluated the following questions: (1) What is the sensitivity and specificity of morphological magnetic resonance imaging (MRI) and dGEMRIC for detecting cartilage damage? Do the mean acetabular and femoral dGEMRIC indices differ between (2) superior acetabular clock positions with and without impingement and (3) between cam- and pincer-type FAI? Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: This was a retrospective comparative study of 21 hips (20 patients with symptomatic anterior FAI) without osteoarthritis on anteroposterior radiographs. Morphological MRI and dGEMRIC (3.0-T, 3-dimensional [3D] T1 maps, dual–flip angle technique) of the same hip joint were compared. Intraoperative acetabular cartilage damage was assessed in patients who underwent surgical treatment. Computed tomography (CT)–based 3D bone models of the same hip joint were used as the gold standard for the detection of impingement, and dGEMRIC indices and zones of morphologic damage were compared with the CT-based impingement zones. Results: Of the 21 hips, 10 had cam-type FAI and 8 had pincer-type FAI according to radiographs. The mean age was 30 ± 9 years (range, 17-48 years), 71% were female, and surgical treatment was performed in 52%. We found a significantly higher sensitivity (69%) for dGEMRIC compared with morphological MRI (42%) in the detection of cartilage damage ( P < .001). The specificity of dGEMRIC was 83% and accuracy was 78%. The mean peripheral acetabular and femoral dGEMRIC indices for clock positions with impingement (485 ± 141 and 440 ± 121 ms) were significantly lower compared with clock positions without impingement (596 ± 183 and 534 ± 129 ms) ( P < .001). Hips with cam-type FAI had significantly lower acetabular dGEMRIC indices compared with hips with pincer-type FAI on the anterosuperior clock positions (1 to 3 o’clock) ( P = .018). Conclusion: MRI with dGEMRIC was more sensitive than morphological MRI, and lower dGEMRIC values were found for clock positions with impingement as detected on 3D-CT. This could aid in patient-specific diagnosis of FAI, preoperative patient selection, and surgical decision making to identify patients with cartilage damage who are at risk for inferior outcomes after hip arthroscopy.

Correlation of Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) Value With Hip Arthroscopy Intraoperative Findings and Midterm Periacetabular Osteotomy Outcomes

“…While there may be a small role for dGEMRIC in localizing isolated acetabular chondral lesions in preoperative patients, 24,31 arthroscopic surgical intervention in and of itself for appropriate pathologies necessitating hip-preservation procedures seems to be a better predictor, albeit an uncontrolled one, of prognosis than dGEMRIC score, as demonstrated by our study and others. 31,35 Schmaranzer et al 35 found significant decreases in preoperative vs minimum 1-year postoperative dGEMRIC scores in operative and nonoperative groups.…”

“…Even so, this study differentiates itself by utilizing coronal and sagittal views. By contrast, Palmer et al 31 utilized only sagittal imaging, while Lerch et al 24 utilized radial imaging volumetrically reconstituted for their studies.…”

Does the dGEMRIC Index Recover 3 Years After Surgical FAI Correction and an Initial dGEMRIC Decrease at 1-Year Follow-up? A Controlled Prospective Study

“…4,6,17,30 While morphologic magnetic resonance imaging (MRI) is limited to a macroscopic and qualitative evaluation of cartilage damage, compositional imaging techniques such as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) allow for quantitative cartilage mapping and therefore enable a more objective assessment of cartilage damage in a noninvasive fashion. 14…”

“…4,6,17,30 While morphologic magnetic resonance imaging (MRI) is limited to a macroscopic and qualitative evaluation of cartilage damage, compositional imaging techniques such as delayed gadolinium-enhanced MRI of cartilage (dGEM-RIC) allow for quantitative cartilage mapping and therefore enable a more objective assessment of cartilage damage in a noninvasive fashion. 14 dGEMRIC is a histologically validated imaging biomarker for cartilage quality that has the potential to improve the understanding of degenerative hip disease and the effect of different treatment protocols on cartilage composition based on the indirect assessment of cartilage glycosaminoglycan content. 23,25 The effect of joint-preserving surgery on cartilage quality in patients with FAI is unclear and has been controversially discussed in the literature.…”