Enhanced reading time efficiency by use of automatically unfolded CT rib reformations in acute trauma

• The presented software unfolding the ribs along a virtual centre line delivers rotatable images of all ribs, which allow a significantly faster diagnosis of rib fractures after acute thoracic trauma with steady high sensitivity.
• Unfolded rib images may have diagnostic value as additional assessment and presentation tool for fast detection of rib fractures because of the display of the whole rib skeleton in one image selection.
• The presented method especially enhances the detection of non-dislocated fractures.

Rationale of this study was to evaluate whether unfolded rib images enhance time efficiency in detection of rib fractures and time efficiency in patients with acute thoracic trauma.51 subsequent patients with thoracic trauma underwent 64-slice computed tomography. 1 mm thick axial slices were reformatted using a commercially available post-processing software application generating rotatable unfolded rib images. Diagnostic accuracy was evaluated by 3 readers and compared to multiplanar reformations of the original CT images. Reformation and evaluation times were recorded.116 rib fractures were detected. The multiplanar reformation analysis yielded a sensitivity of 87.9%/93.9%/79.7% with a specificity of 97%/97%/82.2%, whilst the unfolded rib image analysis yielded a sensitivity of 94.8%/94.8%/92.2% and a specificity of 85.2/87.8%/82.4 (p = 0.06/0.8/0.04) with high inter-observer agreement (k = 0.79–0.85). The mean reading time for the multiplanar reformations was significantly longer (reader 1: 103.7 ± 27.1 s/reader 2: 81.8 ± 40.6 s/reader 3: 154.3 ± 39.2 s) than the evaluation of the unfolded rib images (19.4 ± 4.9 s/26.9 ± 15.0 s/49.9 ± 18.7 s; p < 0.01).Concluding, the unfolded rib display reduces reading time for detection of rib fractures in acute thoracic trauma patients significantly and does not compromise the diagnostic accuracy significantly in experienced radiologists. However, unexperienced readers may profit from use of this display.