The diagnostic utility of CT attenuation values in detecting calcification within costal cartilage

To establish and verify diagnostic criteria for the identification of costal cartilage calcification based on computed tomography (CT) attenuation value.

360 chest CT slices of 120 patients were reviewed and annotated retrospectively and receiver operating characteristic curve was used to evaluate the diagnostic ability of CT attenuation value. Another 20 slices containing calcification were randomly selected and annotated by 4 doctors for further validation. hematoxylin and eosin and collagen type X (COLX) staining was performed on the residual costal cartilage.

In total 355,129 voxels were detected and 187.5 was confirmed as the optimal CT attenuation value threshold, with a sensitivity of 98.6% and a specificity of 99.7%, for costal cartilage calcification diagnosis. Threshold-based identification of calcification demonstrated a similarity of nearly 80% with specialists' assessments, and exhibited advantages in the identification of subtle calcifications in the further validation. We also observed that CT attenuation values among males demonstrated a centralized distribution, whereas those among females exhibited a bimodal distribution. Threshold-based identified calcification showed a positivity of COLX.

CT attenuation value could validly and reliably diagnose calcification within costal cartilage. Further investigations involving larger cohorts of patients are required to elucidate the risk factors and underlying mechanisms of costal cartilage calcification.