Table 4.
Statistical analysis of diagnostic efficiency of each characteristic of MARS MRI in PJI.
| Variable | PJI | Non-PJI |
p- Value a |
Sensitivity | Specificity | Youden’s Index | PPV | NPV | LR+ | LR− |
|---|---|---|---|---|---|---|---|---|---|---|
| Sinus | 4/31 | 0/20 | 0.145 | 12.90% | 100% | 0.129 | 100% | 42.55% | N/A | 0.871 |
| Bone destruction | 17/31 | 5/20 | 0.046 | 54.84% | 75% | 0.298 | 77.27% | 51.72% | 2.194 | 0.602 |
| Bone edema | 23/31 | 10/20 | 0.132 | 74.19% | 50% | 0.242 | 69.70% | 55.56% | 1.484 | 0.516 |
| Lamellated synovitis | 20/31 | 5/20 | 0.009 | 64.52% | 75% | 0.395 | 80.00% | 57.69% | 2.581 | 0.473 |
| Extracapsular edema | 28/31 | 7/20 | <0.001 | 90.32% | 65% | 0.7 | 80.00% | 81.25% | 2.581 | 0.149 |
| Intracapsular collections | 24/31 | 14/20 | 0.743 | 77.42% | 30% | 0.074 | 63.16% | 46.15% | 1.106 | 0.753 |
| Extracapsular collections | 11/31 | 5/20 | 0.543 | 35.48% | 75% | 0.105 | 68.75% | 42.86% | 1.419 | 0.860 |
a Fisher’s exact test; Youden’ s index = sensitivity + specificity − 1; PJI: Prosthetic joint infection, LR+: Positive likelihood ratio, LR−: Negative likelihood ratio, NPV: Negative predictive value, PPV: Positive predictive value, N/A: Not applicable.