Objectives <p>To characterize the distribution and structural patterns of costovertebral joint (CVJ) lesions on CT in SAPHO syndrome and to evaluate their clinical and laboratory associations.</p> Methods <p>This retrospective cross-sectional study included 61 patients with SAPHO syndrome who underwent CT (2018–2024); T1-T12 levels were analyzed. Twenty-three matched controls were included for nonspecific findings. Two blinded radiologists classified SAPHO-specific and nonspecific CVJ lesions. Thoracic involvement and costovertebral joint lesion burden were assessed using a unit-based framework. Associations were tested with Spearman correlation and negative binomial regression; disease duration across ordered lesion subtypes was assessed.</p> Results <p>SAPHO-specific CVJ lesions were present in 23/61 patients (37.7%), including seven with isolated CVJ involvement. Among affected patients, 268 of 966 CVJ units (27.7%) were abnormal, with vertebral-aspect predominance in unilateral lesions (69 vs 5, <i>p</i> &lt; .001) and a mid-thoracic peak (54.5%, <i>p</i> &lt; .001). Inferior half-unit involvement was more frequent than superior half-unit involvement (59.4% vs 40.6%, <i>p</i> = .005). Compared with controls, SAPHO patients had more nonspecific marginal osteophytes (<i>p</i> &lt; .001). Lesion burden correlated with BASFI and BASDAI (<i>p</i> &lt; .050). In multivariable regression, male sex and BASFI were independently associated with higher lesion burden; results were similar when BASDAI was substituted for BASFI (<i>p</i> &lt; .050). Disease duration did not differ across ordered structural subgroups (<i>p</i> &gt; .050).</p> Conclusions <p>CT demonstrates frequent, predominantly vertebral-sided mid-thoracic CVJ involvement in SAPHO syndrome, often affecting inferior half-units and occasionally occurring in isolation. Lesion burden is independently associated with male sex and functional impairment.</p>