Table 4.
Selected studies evaluating diagnostic performance of magnetic resonance imaging, from 2009 to 2012
| Reference | Study design | N | Sensitivity | Specificity |
|---|---|---|---|---|
| Cobben et al [74], 2009 | Prospective. Patients, age 6–80 y, with clinically suspected appendicitis. Breath hold, unenhanced MRI with T1, T2, and T2 fat-suppressed sequences. Nonsurgical patients followed up in clinic at 1 wk and followed as outpatient for at least 2 y. | 138 | 100 | 98 |
| Barger and Nandalur [73], 2010 | Meta-analysis. 8 prospective and retrospective articles included; studies included if the absolute numbers of true-positive, true-negative, false-positive, and false-negative results were reported. | 363 | 97a | 95a |
| Chabanova et al [102], 2011 | Prospective. Adult patients with clinically diagnosed appendicitis. Unenhanced MRI with T1, T2, and fat-suppressed sequences. All patients underwent surgery. | 48 | 87b | 61 |
| Inci et al [72], 2011 | Prospective. Patients, age 14–72 y, with clinically suspected appendicitis. Unenhanced MRI with T1, T2, and fat-suppressed sequences. Clinical follow-up for 1–3 mo for nonsurgical patients. | 85 | 96.5 | 66.7c |
| Johnson et al [103], 2012 | Prospective. Pediatric patients, age 4–17 y, with acute abdominal pain suspicious for appendicitis. All subjects underwent MRI as well as CT or US. (MR sequences = single-shot turbo spin-echo T2 in 3 planes and T2 fat-suppressed axial sequence.) No specific mention of follow-up protocol for nonsurgical patients. | 42 | 100 | 99 |
| Moore et al [104], 2012 | Retrospective. Pediatric patients, age 3–17 y, with suspected appendicitis. Unenhanced MRI with single-shot turbo spin-echo coronal T2, axial T2, and axial fat saturation T2, as well as a coronal SPAIR. Follow-up for nonsurgical patients based on chart review and discharge diagnosis. | 208 | 97.6 | 97.0 |
Barger and colleagues calculated 95% CIs for their meta-analysis; for sensitivity,a 95% CI is 92%–99% and for specificity,a it is 94%–99%. In the study by Chabanova and colleagues, although MRI was 87% sensitive for appendicitis,b it was 100% sensitive in detecting pelvic abnormalities (ie, the radiologist called appendicitis but other disease found in the operating room). Of the 4 patients with no pathologic abnormalities, 3 were correctly identified by MRI, yielding a specificity of 75%. In the study by Inci and colleagues, by our calculation, specificityc is 89.3% (true negatives/[true negatives + false positives]); the investigators report 25 true-negative, 2 false-negative, 55 true-positive, and 3 false-positive cases (“probable appendicitis” was treated as a positive result in this study). Sensitivity of 96.5% is consistent with the raw numbers reported.
Abbreviation: SPAIR, spectral adiabatic inversion recovery.