The impact of iodinated contrast medium on bone mineral density (BMD) quantification in computed tomography: a monocentric retrospective study evaluating phases, sex and age differences.

Purpose: The primary purpose of this study was to assess the impact of iodinated contrast medium on bone mineral density (BMD) measurement in CT scans. The secondary purpose was to evaluate the impact of contrast medium on different acquisition phases, stratified by sex and age.

Material And Methods: CT examinations acquired in the emergency room between January 2019 and September 2021, before and after contrast medium administration, were included. On axial images, a round region of interest was traced on the first lumbar vertebra and the Hounsfield units (HU) values were recorded. Statistical analysis compared BMD differences across different acquisition phases. Stratified analyses by sex and age were also performed. Significance was set at p < 0.05.

Results: A total of 295 CT acquisitions from 100 patients (52 males; 48 females) were included. There was a significant difference in BMD among native, arterial and portal venous phases (p < 0.001). Specifically, BMD in arterial and venous phases differed significantly from the native phase (p = 0.007 and p < 0.001, respectively). Males showed a BMD higher of 19.1 points compared to females (p = 0.0007); younger people showed a higher BMD compared to older people (p < 0.001). Overall, significant differences in density emerged between phases in all stratified analyses.

Conclusion: Unenhanced and enhanced CT shows significant differences in BMD quantification, particularly when comparing the venous and native phases. These differences were consistent across analyses performed according to sex and age.