Computed tomography-based opportunistic osteoporosis assessment: a comparison of two software applications for lumbar vertebral volumetric bone mineral density measurements

Background: We aimed to compare two volumetric bone mineral density (vBMD) analysis programs, regarding (I) agreement of vBMD values based on monoand dual-energy computed tomography (MECT and DECT) scans and (II) suitability for analyzing DECT data obtained at different energies. Methods: We retrospectively analyzed two abdominal CT datasets: one performed in a MECT scan (vertebrae L1-L3) and one in a DECT scan (vertebrae L1-L4). Each dataset included different individuals [MECT 15 patients (45 vertebrae) and DECT 12 patients (48 vertebrae), respectively]. vBMD analysis was conducted using Philips IntelliSpace (IP) and Mindways qCT Pro (MW). Regarding the DECT scans, vBMD analysis was done at three different energies: 80, 150 and synthetic 120 kVp and for MECT scan at 120 kVp. For comparison of vBMD results between different software (aim 1) MECT 120 kVp and DECT synthetic 120 kVp data was used. For analyzing suitability of using different DECT energies for vBMD assessment (aim 2) all three DECT energies were used and results from each software was analyzed separately. Results: vBMD assessed with MW and IP, respectively correlated significantly for both the MECT (r=0.876; P<0.001) and DECT (r=0.837; P<0.001) scans, but the vBMD values were lower in using IP for vBMD assessment (8% and 14% lower for MECT and DECT, respectively; P=0.001). Regarding the different DECT energies, using MW for vBMD assessment showed significant correlations in vBMD results between 120 kVp and the two other energies (r=0.988 and r=0.939) and no significant differences in absolute vBMD values (P 0.05). The IP analysis as well showed significant correlation between 120 kVp and the other energies (r=0.769 and r=0.713, respectively), but differences in absolute vBMD values between the energies (P <= 0.001). Conclusions: We show that the correlations between the vBMD derived from the two investigated software solutions were generally good but that absolute vBMD value did differ and might impact the clinical diagnosis of osteoporosis. Though small, our study data indicate that vBMD might be assessed in energies other than 120 kVp when using MW but not when using IP.