The utility of computed tomography in evaluating rib fractures in live children investigated for suspected physical abuse

Abstract

Rib fractures are strongly associated with physical abuse in infants and young children. Computed tomography (CT) may be an accurate diagnostic tool when compared to chest radiography, the current imaging standard, for detecting rib fractures in children with suspected physical abuse (SPA). A systematic review showed that CT has better diagnostic accuracy than initial chest radiographs (CXR) for detecting rib fractures in children with SPA.

A multicentre retrospective observational study was conducted to assess the diagnostic accuracy of chest CT for detecting rib fractures in children under 2 years investigated for SPA, using initial and follow-up CXRs as the reference standard. An analysis of 64 of these cases showed overall accuracy of CT as 83.72%, 93.46% and 96.47%, per-patient, rib and location, respectively. A sub-study of the multicentre study, conducted to assess the feasibility of dating rib fractures using CT, showed substantial agreement between chest radiography and CT in estimating broad timeframes for rib fracture dating (acute vs. healing) (kappa (k)=0.76). Callus formation features on CT scans showed a discriminative pattern for estimating the specific age range of rib fractures.

Concerns regarding higher radiation exposure of CT compared to chest radiography have made CT less desirable in routine clinical practice when evaluating children with SPA. A study using post-mortem animal models at two paediatric centres to optimise chest CT scanning parameters gave these sets with the lowest radiation dose and acceptable diagnostic image quality (≥3 out of 5): Centre 1: 80 kV/30 mA, effective dose 0.32 millisieverts (mSv), 93.5% sensitivity; Centre 2: 80 kV/40 mA, effective dose 0.2 mSv, 84.3% sensitivity.

Compared to the current clinical standard (initial and follow-up CXRs), chest CT shows high diagnostic accuracy. Furthermore, dating rib fractures from chest CT and optimising its radiation dose seems to be possible.