Inverting Grayscale Improves Detection of Proximal Femur Fracture

Inverting Grayscale in Conventional Orthopedics X-rays Improves Detection of Proximal Femur Fracture Among Undergraduate Medical Students

Proximal femur fractures (PFF) are a worldwide public health concern. A delay in the diagnosis and treatment worsens the prognosis. Inversion of grayscale is a tool available on most X-rays visualization software, and its use has been suggested to improve radiological diagnosis. The study aims to determine if using inverted grayscale radiography results in better diagnoses of PFF among medical students. Material and Methods. The investigators evaluated the detection of PFF by fifth-year medical students on a series of 30 pelvis X-rays. The series was composed of 20 X-rays with PFF and 10 X-rays without fracture. A first reading session was set up where X-rays were presented separately in conventional and inverted grayscale. A second session one month later showed both grayscale visualizations together (BIcontrast X-rays Analysis Method - BIXAM). X-rays' order of appearance was randomized. The investigators performed the same evaluation on senior orthopedic surgeons as a control. Finally, sensitivity, specificity, and accuracy were assessed for each method (conventional, inverted, and BIXAM) with the McNemar test. Subgroup analyses were performed on the fracture localization (femoral neck, trochanteric).

We built two series of images. Series one was composed of separated conventional and inverted images. Series two consisted of inverted and conventional X-rays of the same subject (BIXAM) shown together (Figure). An independent assessor randomly duplicated four and two images for series one and two, respectively, to evaluate the intra-observer agreement. The same assessor randomized the images' order of appearance for the two series with a free online available list randomizer (www.randomizer.org). The principal investigator was blinded to the randomization during the sessions.

As controls, we asked 3 independent board-certified orthopedic surgeons to participate in the study following the same conditions as described previously.

accuracy was compared between conventional and inverted grayscales or both images shown together (BIXAM series) with non-parametric McNemar test

Sensibility, specificity were compared between conventional and inverted grayscales or both images shown together (BIXAM series) with non-parametric McNemar test