CT of the chest in suspected child abuse using submillisievert radiation dose

Abstract

The cornerstone of child abuse imaging is the skeletal survey, but initial imaging with radiographs may not demonstrate acute and non-displaced fractures, especially those involving the ribs. Given the high mortality of undiagnosed non-accidental trauma, timely diagnosis is crucial. CT is more sensitive in assessing rib fractures; however the effective radiation dose of a standard chest CT is high. We retrospectively identified four children (three boys, one girl; age range 1-4 months) admitted between January 2013 and February 2014 with high suspicion for non-accidental trauma from unexplained fractures of the long bones; these children all had CT of the chest when no rib fractures were evident on the skeletal survey. The absorbed radiation dose estimates for organs and tissue from the four-view chest radiographs and subsequent CT were determined using Monte Carlo photon transport software, and the effective dose was calculated using published tissue-weighting factors. In two children, CT showed multiple fractures of the ribs, scapula and vertebral body that were not evident on the initial skeletal survey. The average effective dose for a four-view chest radiograph across the four children was 0.29 mSv and the average effective dose for the chest CT was 0.56 mSv. Therefore the effective dose of a chest CT is on average less than twice that of a four-view chest radiograph. Our protocol thus shows that a reduced-dose chest CT may be useful in the evaluation of high specificity fractures of non-accidental trauma when the four-view chest radiographs are negative.

Imaging of non‐accidental injury; what is clinical best practice?

“…The authors found no significant difference between the sensitivity of skull radiographs and head CT with 3D reconstructions in identifying skull fractures. Sanchez et al reviewed the examinations of four children requiring CT of the chest in addition to the skeletal survey, and found that the average effective dose for reduced‐dose chest CT was 0.56 mSv.…”

Modern post-mortem imaging: an update on recent developments

“…In cases of infant death, if magnetic resonance imaging (MRI) is not possible for technical, or practical reasons (no MR unit accessible, personnel for MRI not available), PMCT is mandatory if available, as skeletal injuries or malformations are often difficult to see in a conventional autopsy [ 21 , 22 ]. Also, it must be noted that radiological examination of infant bodies can be used in non-forensic cases as the parents frequently will not agree to an autopsy.…”

Chest radiographs versus CT for the detection of rib fractures in children (DRIFT): a diagnostic accuracy observational study

“…The limitations of chest radiography for the investigation of rib fractures are recognised by experienced reporters, 18 and CT has been proposed as an improved method of rib fracture detection 19 . Three previous studies comparing CT with radiography for rib fracture detection have either been case series 20 in live children without autopsy correlation, 7 or underpowered with single-reporter bias 13 . Wootton-Gorges and colleagues 7 suggested that CT was superior for all rib fracture locations (anterior, lateral, and posterior), because only 79 (60%) of 131 fractures identified by use of CT were found by use of radiography in 12 live children, although only four children had complete CT scans of the chest and none had autopsy correlation.…”