Feasibility of Opportunistic Peripheral Bone Mineral Density and Structural Quantification Using an Ultra-Low Dose Multi-Detector Ct Publisher Pubmed



Malekzadeh M ; Keyak J ; Mobini N ; Yazdani E ; Abbasi Rad S ; Tofighirad N ; Shamsi M ; Ardakani A A ; Shiran M B ; Rad H S
Source: Biomedical Physics and Engineering Express Published:2026

Abstract

Quantitative computed tomography (QCT) enables accurate assessment of volumetric bone mineral density (vBMD) and bone structure. Peripheral QCT (pQCT) and high-resolution pQCT (HR-pQCT) have been proposed as lower-dose alternatives to conventional QCT; however, their limited availability restricts widespread clinical and research use. To investigate the feasibility of using ultra–low-dose multi-detector computed tomography (MDCT) with a hybrid iterative reconstruction (HIR) algorithm for quantifying tibial vBMD, using synchronous liquid and solid calibration phantoms. Fifty volunteers (28 women and 22 men; age range: 30–60 yr; T-score ⩾ −1) without metabolic bone disorders, were scanned using a Philips-Brilliance MDCT scanner. To minimize radiation exposure, vBMD was quantified at the 38% distal tibial site using either a liquid calibration phantom (50, 100, and 200 mg cm−3 dipotassium hydrogen phosphate [K2HPO4]) or a solid calibration phantom (50, 100, and 250 mg cm−3 calcium hydroxyapatite [CHA]). A cross-calibration equation was applied to derive equivalent vBMD values between phantom types. Cortical bone structure was evaluated using a semi-automated segmentation approach. Following cross-calibration, BMDK2HPO4 = 1.34 BMDCHA + 13.43, mean cortical vBMD values were 1188.07 ± 29.38 mg cm−3 (CHA) and 1600.92 ± 39.51 mg cm−3 (K2HPO4). The CHA-based cortical vBMD values were consistent with solid-based pCT measurements reported in the literature. Mean cortical thickness was approximately 5 mm. The estimated effective radiation dose is approximately 10 µSv, corresponding to daily background radiation levels. This preliminary study demonstrates the feasibility of using HIR-based ultra–low-dose MDCT for peripheral tibial vBMD and structural assessment at the 38% distal site. This approach offers a promising opportunistic alternative in clinical and research settings where pQCT or HR-pQCT systems are unavailable. © 2026 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.