Post-mortem skeletal survey (PMSS) versus post-mortem computed tomography (PMCT) for the detection of corner metaphyseal lesions (CML) in children.

OBJECTIVES: Corner metaphyseal lesions (CMLs) are specific for child abuse but challenging to detect on radiographs. The accuracy of CT for CML detection is unknown. Our aim was to compare diagnostic accuracy for CML detection on post-mortem skeletal surveys (PMSS, plain radiography) versus post-mortem CT (PMCT).

METHODS: A 10-year retrospective review was performed at a children's hospital for patients having PMSS, PMCT and histopathological correlation (reference standard) for suspected CMLs. Twenty-four radiologists independently reported the presence or absence of CMLs in all cases in a blinded randomised cross-over design across two rounds. Logistic regression models were used to compare accuracy between modalities.

RESULTS: Twenty CMLs were reviewed for each of the 10 subjects (200 metaphyses in all). Among them, 20 CMLs were confirmed by bone histopathology. Sensitivity for these CMLs was significantly higher for PMSS (69.6%, 95% CI 61.7 to 76.7) than PMCT (60.5%, 95% CI 51.9 to 68.6). Using PMSS for detection of CMLs would yield one extra correct diagnosis for every 11.1 (95% CI 6.6 to 37.0) fractured bones. In contrast, specificity was higher on PMCT (92.7%, 95% CI 90.3 to 94.5) than PMSS (90.5%, 95% CI 87.6 to 92.8) with an absolute difference of 2.2% (95% CI 1.0 to 3.4, p < 0.001). More fractures were reported collectively by readers on PMSS (785) than on PMCT (640).

CONCLUSION: PMSS remains preferable to PMCT for CML evaluation. Any investigation of suspected abuse or unexplained deaths should include radiographs of the limbs to exclude CMLs.

CLINICAL RELEVANCE STATEMENT: In order to avoid missing evidence that could indicate child abuse as a contributory cause for death in children, radiographs of the limbs should be performed to exclude CMLs, even if a PMCT is being acquired.

KEY POINTS: • Corner metaphyseal lesions (CMLs) are indicative for abuse, but challenging to detect. Skeletal surveys (i.e. radiographs) are standard practice; however, accuracy of CT is unknown. • Sensitivity for CML detection on radiographs is significantly higher than CT. • Investigation of unexplained paediatric deaths should include radiographs to exclude CMLs even if CT is also being performed.