Case discussions of missed traumatic fractures on computed tomography scans

Abstract

Radiological diagnostic errors are common and may have severe consequences. Understanding these errors and their possible causes is crucial for optimising patient care and improving radiological training. Recent postmortem studies using an animal model highlighted the difficulties associated with accurate fracture diagnosis using radiological imaging. The present study aimed to highlight the fact that certain fractures are easily missed on CT scans in a clinical setting and that caution is advised. A few such cases were discussed to raise the level of suspicion to prevent similar diagnostic errors in future cases. Records of adult patients from the radiological department at an academic hospital in South Africa were retrospectively reviewed. Case studies were selected by identifying records of patients between January and June 2021 where traumatic fractures were missed during initial imaging interpretation but later detected during secondary analysis or on follow-up scans. Seven cases were identified, and the possible causes of the diagnostic errors were evaluated by reviewing the history of each case, level of experience of each reporting radiologist, scan quality and time of day that initial imaging interpretation of each scan was performed. The causes were multifactorial, potentially including a lack of experience, fatigue, heavy workloads or inadequate training of the initial reporting radiologist. Identifying these causes, openly discussing them and providing additional training for radiologists may aid in reducing these errors.

Contribution: This article aimed to use case examples of missed injuries on CT scanning of patients in a South African emergency trauma setting in order to highlight and provide insight into common errors in scan interpretation, their causes and possible means of mitigating them.

Keywords: diagnostic errors; emergency department; fracture misdiagnoses; radiology; traumatic fractures.

FIGURE 1

Comparison of percentage of blunt (BFT) and sharp force (SFT) lesions detected by CT, X-ray and Lodox in various body regions in a postmortem context using a pig model. Piglets (black bars) were included to simulate cases of child abuse. (a) Skull, (b) ribs, (c) vertebrae, (d) forelimbs, (e) hindlimbs. Percentages taken from Spies et al.^,,,

FIGURE 2

Axial (a and b) and coronal (c) reconstructions of the cervical spine CT showing comminuted fractures of the left superior and inferior facets of C4 (black arrow) and left lamina of C4 (white arrow). Sagittal (d) reconstruction shows a small avulsion fracture of the anterosuperior margin of the C4 vertebral body (black arrow). These fractures represent an unstable cervical spine injury.

FIGURE 3

Sagittal reconstruction of the initial CT of the cervical spine (a) showing the C4 spinous process fracture (black arrow). The follow-up CT (b) shows worsened retrolisthesis of the C4 on C5 vertebra with an anterior teardrop fracture of the C4 vertebra (white arrow). This fracture is visible in (a) but was called a ‘fractured osteophyte’ (white arrowhead). The axial (c) and coronal (d) reconstructions of the scan show how the degenerative cervical spine changes may make diagnosing fractures challenging – the teardrop fracture is pointed out by the white arrow in (c) and may have been misinterpreted as an osteophyte (white arrowhead). The black arrowhead in (c) demonstrates a right lamina fracture, and the black arrow again points out the spinous process fracture.

FIGURE 4

Paramidline sagittal (a and b) reconstructions of a cervical spine CT showing a fracture of the right inferior facet of the C6 vertebra (black arrow), a fracture of the right superior facet of the C7 vertebra (white arrow) and a fracture of the anterosuperior margin of the body of C7 (black arrowhead). A midline sagittal reconstruction (c) demonstrates reversed cervical spine lordosis but no listhesis. Associated prevertebral soft tissue swelling is present (white asterisk). Note that the patient was ‘scanned skew’ (d).

FIGURE 5

Axial CT of the head (a) demonstrating the depressed right squamous temporal bone fracture (black arrow) detected on initial interpretation. An oblique reconstruction of the right temporal bone (b) shows that the fracture (white arrow) extends into the facial nerve canal (highlighted here by the white dots). Specifically, it involves the tympanic segment of the canal. The fracture line extending into the mastoid part of the temporal bone is pointed out by the black arrowhead in the axial image (c) – note the fluid in the mastoid air cells and compare it to the well-aerated left mastoid air cell; a secondary sign of temporal bone fracture. The fracture line (white arrowhead) is much more conspicuous on the axial cut of the bone reconstruction algorithm (d) than the soft tissue algorithm (e), despite both being set to a standard ‘bone window’.

FIGURE 6

A CT pan-scan showing extensive subcutaneous emphysema of both the head (a) and chest (b). When viewed without straightening the scan using multiplanar reconstruction (c), the right temporal bone otic capsule–sparing fracture is not easy to detect even utilising the bone reconstruction algorithm (black arrow) and nearly invisible (white arrow) on the soft tissue reconstruction algorithm (d). The bone window (e) demonstrates an initially overlooked nondisplaced right 9th rib fracture (black arrowhead). Note the right haemothorax (black star) and pneumothorax (white star) seen on the lung window of the chest CT (f). Also note that the patient was ‘scanned skew’.

FIGURE 7

Axial bone reconstruction of a CT (a and b) of the chest demonstrating subtle buckle-type fractures of the 10th and 11th ribs (black arrows) associated with a small lung contusion (white arrow).

FIGURE 8

Axial bone reconstruction CT of a the chest demonstrating a minimally displaced second rib fracture (black arrow) associated with a small lung laceration and contusion (white arrow). As with cases 5 and 6, lung injuries such as contusions or lacerations should prompt careful search for associated rib fractures in the trauma patient.