Table 2.
Summary of the results for each imaging modality compared to compensated polarised light microscopy
| Imaging modality\pathology and statistical results | Dual energy computed tomography n = 36 |
Musculoskeletal ultrasound n = 36 |
Conventional radiographs n = 32 |
Suspected clinical diagnosis n = 36 |
|---|---|---|---|---|
| Acute gout flares | ||||
|
Sensitivity (95% CI) |
63% (0.41–0.81) | 92% (0.73–0.99) | 65% (0.41–0.85) | 88% (0.68–0.97) |
|
Specificity (95% CI) |
92% (0.62–1.00) | 83% (0.52–0.98) | 100% (0.74–1.00) | 75% (0.43–0.95) |
| PPV | 94% | 92% | 100% | 88% |
| NPV | 55% | 83% | 63% | 75% |
| Positive likelihood ratio | 7.5 | 5.5 | Inf | 3.5 |
| Negative likelihood ratio | 0.4 | 0.1 | 0.35 | 0.167 |
| Acute CPP crystal arthritis | ||||
|
Sensitivity (95% CI) |
55% (0.23–0.83) | 91% (0.59–1.00) | 36% (0.11–0.69) | 82% (0.48–0.98) |
|
Specificity (95% CI) |
92% (0.74–0.99) | 92% (0.74–0.99) | 90% (0.70–0.99) | 88% (0.69–0.97) |
| PPV | 75% | 83% | 67% | 75% |
| NPV | 82% | 96% | 73% | 92% |
| Positive likelihood ratio | 6.818 | 11.364 | 3.818 | 6.818 |
| Negative likelihood ratio | 0.494 | 0.099 | 0.703 | 0.207 |
Sensitivities and specificities of examinations for acute gout flares and acute calcium pyrophosphate crystal arthritis (95% confidence intervals in brackets). n denotes the number of data sets for each modality. PPV, positive predictive value; NPV, negative predictive value