Diagnostic performance of spectral CT in detecting bone marrow edema for vertebral fracture: A multi-reader study

To evaluate the spectral scanner (Aquilion One PRISM Edition, Canon Medical Systems Corporation, Otawara, Japan) diagnostic performance to identify bone marrow edema (BME) in vertebrae of patients managed for suspected vertebral compression fracture in the emergency department of Dijon University Hospital.

14 consecutive patients underwent spectral imaging and MRI spinal imaging, from January 2023 to March 2024 were retrospectively analyzed. 85 vertebrae were assessed for the detection of fracture on conventional CT images and the presence of bone marrow edema (BME) in all vertebral bodies on VNCa mapping for both Bone and Research preset, who was judged to indicate a fresh fracture. The mean attenuation coefficients and standard deviations were measured for both Bone and Research preset and each mapping (VNCa 1 mm and 3 mm, water and electron density mapping) using the t-test. Sensitivity, specificity, PPV and NPV analyses for diagnostic performance were performed.

The proportion of true positive cases among the positive cases detected by both Bone and Research preset was respectively 95 % and 100 %, and the proportion of true negative cases among the negative cases was respectively 94 % and 95 %. Positive and negative likelihood ratios were excellent, particularly for the Research preset. The attenuation values of vertebral bodies with BME on spectral CT, measured using ROI on virtual non-calcium maps, were statistically higher than those in vertebral bodies without edema.

Spectral CT showed good diagnostic accuracy, but also good discrimination capability in identifying the presence of BME in a vertebral body. Its diagnostic performance was very close to that of MRI. Thus, the detection of BME in a vertebral body by spectral CT greatly increased the probability of a recent or unhealed fracture in this vertebra. The present results suggest that the use of the spectral scanner to discriminate a recent or unhealed vertebral fracture from a union fracture could be considered.