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Prospective comparison of MR imaging and US for the diagnosis of pediatric appendicitis
Robert C Orth1, R Paul Guillerman, Wei Zhang
1From the Edward B. Singleton Department of Pediatric Radiology (R.C.O., R.P.G., P.M., G.S.B.) and Surgical Outcomes Center (W.Z.), Texas Children's Hospital, Baylor College of Medicine, 6701 Fannin St, MC CC470.01, Houston, TX 77030.
Insights
Nonenhanced magnetic resonance (MR) imaging shows high accuracy for diagnosing pediatric appendicitis, performing similarly to ultrasonography (US). This study found MR imaging to be a reliable alternative for pediatric appendicitis diagnosis.
Area of Science:
- Radiology
- Pediatric Imaging
- Diagnostic Accuracy
Background:
- Appendicitis is a common surgical emergency in children.
- Accurate diagnosis is crucial to avoid complications and unnecessary surgery.
- Nonenhanced magnetic resonance (MR) imaging offers a radiation-free alternative for abdominal imaging.
Purpose of the Study:
- To prospectively compare the diagnostic performance of nonenhanced MR imaging versus ultrasonography (US) for pediatric appendicitis.
- To evaluate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of both imaging modalities.
Main Methods:
- Eighty-one pediatric patients with suspected appendicitis underwent both US and nonenhanced abdominopelvic MR imaging.
- Two blinded pediatric radiologists independently reviewed MR images.
- Diagnostic performance metrics and inter-reader/inter-technique agreement were calculated.
Main Results:
- Nonenhanced MR imaging demonstrated high sensitivity (93.3%) and specificity (98%) when equivocal results were considered positive.
- MR imaging showed comparable or superior performance to US across all metrics, including PPV (96.5% vs. 79.4%) and NPV (96.2% vs. 93.6%).
- Substantial intertechnique agreement (κ=0.77) and interobserver agreement (κ=0.76) were observed for MR imaging.
Conclusions:
- Nonenhanced MR imaging is a highly accurate tool for diagnosing pediatric appendicitis.
- Its diagnostic performance is comparable to that of US, offering a valuable alternative, especially in cases where US is inconclusive.
- The study supports the use of nonenhanced MR imaging in the pediatric appendicitis workup.
Purpose:
To prospectively compare nonenhanced magnetic resonance (MR) imaging and ultrasonography (US) for the diagnosis of pediatric appendicitis.
Materials And Methods:
This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained from the patient's parent or guardian. Eighty-one patients (34 male, 47 female; mean age, 12.3 years ± 3.5 [standard deviation]; range, 4-17 years) were enrolled in this prospective study. All patients underwent right lower quadrant US and nonenhanced, nonsedated abdominopelvic MR imaging examinations. Two pediatric radiologists blinded to US results independently reviewed the MR images. MR imaging and US findings were designated positive, negative, or equivocal for acute appendicitis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for MR imaging and US and compared by using two-sided McNemar test or the score statistics specified by Leisenring. Kappa statistics were generated to determine intertechnique agreement between MR imaging and US and interobserver agreement between the two primary MR imaging readers.
Results:
Thirty (37%) patients had pathologically proved acute appendicitis. When equivocal interpretations were designated positive, sensitivity was 93.3% for MR imaging (95% confidence interval [CI]: 77.9%, 99.2%) and 90.0% for US (95% CI: 73.5%, 97.9%), P > .99; specificity was 98% for MR imaging (95% CI: 89.6%, 100%) and 86.3% for US (95% CI:73.7%, 94.3%), P = .03; PPV was 96.5% for MR imaging (95% CI: 82.2%, 99.9%) and 79.4% for US (95% CI: 62.1%, 91.3%), P = .007; and NPV was 96.2% for MR imaging (95% CI: 86.8%, 99.5%) and 93.6% for US (95% CI: 82.4%, 98.7%), P = .45, with substantial intertechnique (κ = 0.77; 95% CI: 0.63, 0.90) and interobserver (κ = 0.76; 95% CI: 0.61, 0.91) agreement. When equivocal interpretations were designated negative, MR imaging sensitivity, specificity, PPV, and NPV were unchanged. For US, sensitivity was 86.7% (95% CI: 69.3%, 96.2%), P = .5; specificity was 100% (95% CI: 93.0%, 100%), P > .99; PPV was 100% (95% CI: 86.8%, 100%), P = .31; and NPV was 92.7% (95% CI: 82.4%, 98.0%), P = .16, with almost perfect intertechnique (κ = 0.92; 95% CI: 0.83, 1.00) and substantial interobserver (κ = 0.72; 95% CI: 0.58, 0.87) agreement.
Conclusion:
Nonenhanced MR imaging demonstrates high diagnostic performance similar to that of US for suspected pediatric appendicitis.
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