Diagnostic Value of Advanced Metal Artifact Reduction Magnetic Resonance Imaging for Periprosthetic Joint Infection
Tsutomu Inaoka1, Noriko Kitamura1, Masayuki Sugeta1
1From the Department of Radiology.
Materials And Methods:
Magnetic resonance imaging around metal joint prostheses including multiacquisition variable-resonance image combination selective at 1.5 T (from April 2014 to August 2020) was retrospectively evaluated by 2 radiologists for detection of abnormal findings (joint effusion, capsular thickening, pericapsular edema, soft-tissue fluid collection, soft-tissue edema, bone marrow edema pattern around the implant [BME pattern], lymphadenopathy, and others) and overall image impression for PJI. Regarding the soft-tissue fluid collection, presence of communication to the joint or capsular-like structure was evaluated. Clinical assessments were recorded. Positive predictive values (PPVs), negative predictive values (NPVs), and odds ratios (ORs) for PJI were calculated for the abnormal findings. Overall image impression for PJI was evaluated. χ2, Fisher exact, t, and Mann-Whitney U tests and receiver operating characteristic analysis were used. Interobserver agreement was assessed with κ statistics.
Results:
Forty-three joints in 36 patients (mean ± SD age, 75.4 ± 8.8 years; 30 women; hip [n = 29], knee [n = 12], and elbow [n = 2]) were evaluated. Eighteen joints (42%) were clinically diagnosed as PJI. The findings suggesting PJI were capsular thickening (PPV, 70%; NPV, 90%; OR, 20.6), soft-tissue fluid collection (PPV, 81%; NPV, 81%; OR, 19.1), soft-tissue edema (PPV, 67%; NPV, 89%; OR, 17), pericapsular edema (PPV, 76%; NPV, 81%; OR, 13.7), and joint effusion (PPV, 55%; NPV, 100%; OR, 12). Soft-tissue fluid collection without capsular-like structure (PPV, 83%; NPV, 74%; OR, 14.4) or with communication to the joint (PPV, 75%; NPV, 71%; OR, 7.3) suggested PJI. The combinations of joint effusion, capsular thickening, pericapsular edema, soft-tissue fluid collection, and soft-tissue edema highly suggested PJI. Regarding the BME pattern, the combination with soft-tissue edema raised the possibility of PJI (PPV, 73%; NPV, 69%; OR, 5.9). Regarding the interobserver agreements for each abnormal finding, κ values were 0.60 to 0.77. Regarding the overall image impression, weighted κ value was 0.97 and areas under the receiver operating characteristic curve were 0.949 (95% confidence interval, 0.893-1.005) and 0.926 (95% confidence interval, 0.860-0.991) with no significant difference (P = 0.534).
Conclusions:
The findings suggesting PJI were capsular thickening, soft-tissue fluid collection, soft-tissue edema, pericapsular edema, and joint effusion. The combinations of them highly suggested PJI. Regarding the BME pattern, the combination with soft-tissue edema raised the possibility of PJI.
Insights
Magnetic resonance imaging effectively detects periprosthetic joint infection (PJI) by identifying specific findings like capsular thickening and fluid collections. Combinations of these imaging findings strongly suggest PJI, aiding in diagnosis.
Area of Science:
- Orthopedic imaging
- Radiology
- Infectious disease diagnostics
Background:
- Periprosthetic joint infection (PJI) is a serious complication following joint replacement surgery.
- Accurate diagnosis of PJI is crucial for timely and effective treatment.
- Magnetic resonance imaging (MRI) is a valuable tool for evaluating complications around metal joint prostheses.
Purpose of the Study:
- To evaluate the diagnostic performance of various MRI findings for detecting PJI.
- To assess the utility of combining multiple MRI findings for improved PJI detection.
- To determine the accuracy of MRI in identifying abnormal findings suggestive of PJI.
Main Methods:
- Retrospective evaluation of MRI scans (1.5 T) in patients with metal joint prostheses.
- Two radiologists assessed findings including joint effusion, capsular thickening, edema, and fluid collections.
- Calculation of positive and negative predictive values (PPVs and NPVs) and odds ratios (ORs) for PJI.
Main Results:
- Capsular thickening, soft-tissue fluid collection, soft-tissue edema, pericapsular edema, and joint effusion were significant indicators of PJI.
- Combinations of these findings showed high diagnostic value for PJI.
- Bone marrow edema pattern (BME pattern) in combination with soft-tissue edema also suggested PJI.
Conclusions:
- Specific MRI findings such as capsular thickening and soft-tissue fluid collections are highly suggestive of PJI.
- The combination of multiple MRI abnormalities significantly increases the likelihood of PJI.
- MRI is a reliable imaging modality for the diagnosis of PJI in patients with joint prostheses.
