Ultrashort echo time MRI detects significantly lower collagen but higher pore water in the tibial cortex of female patients with osteopenia and osteoporosis

Saeed Jerban; Yajun Ma; Zhao Wei; Meghan Shen; Zubaid Ibrahim; Hyungseok Jang; Pengzhe Lu; Douglas G Chang; Gina Woods; Christine B Chung; Eric Y Chang; Jiang Du

doi:10.1093/jbmr/zjae053

Ultrashort echo time MRI detects significantly lower collagen but higher pore water in the tibial cortex of female patients with osteopenia and osteoporosis

J Bone Miner Res. 2024 Apr 9:zjae053. doi: 10.1093/jbmr/zjae053. Online ahead of print.

Authors

Saeed Jerban¹, Yajun Ma¹, Zhao Wei¹, Meghan Shen¹, Zubaid Ibrahim¹, Hyungseok Jang¹, Pengzhe Lu^{2

3}, Douglas G Chang⁴, Gina Woods⁵, Christine B Chung^{1

2}, Eric Y Chang^{1

2}, Jiang Du^{1

2}

Affiliations

¹ Department of Radiology, University of California, San Diego, CA, United States.
² Research Service, VA San Diego Healthcare System, San Diego, CA, United States.
³ Department of Neurosciences, University of California, San Diego, CA, United States.
⁴ Department of Orthopaedic Surgery, University of California, San Diego, CA, United States.
⁵ Department of Medicine, University of California, San Diego, San Diego, CA, United States.

PMID: 38591788
DOI: 10.1093/jbmr/zjae053

Abstract

Ultrashort echo time (UTE) MRI can quantify the major proton pool densities in cortical bone, including total (TWPD), bound (BWPD), and pore water (PWPD) proton densities, as well as the macromolecular proton density (MMPD), associated with the collagen content, which is calculated using macromolecular fraction (MMF) from UTE magnetization transfer (UTE-MT) modeling. This study aimed to investigate the differences in water and collagen contents in tibial cortical bone, between female osteopenia (OPe) patients, osteoporosis (OPo) patients, and young participants (Young). Being postmenopausal and above 55 years old were the inclusion criteria for OPe and OPo groups. The tibial shaft of fourteen OPe (72.5 ± 6.8 years old), thirty-one OPo (72.0 ± 6.4 years old), and thirty-one young subjects (28.0 ± 6.1 years old) were scanned using a knee coil on a clinical 3 T scanner. Basic UTE, inversion recovery UTE, and UTE-MT sequences were performed. Investigated biomarkers were compared between groups using Kruskal-Wallis test. Spearman's correlation coefficients were calculated between the total hip dual-energy x-ray absorptiometry (DXA) T-score and UTE-MRI results. MMF, BWPD, and MMPD were significantly lower in OPo patients than in the young group. Whereas T1, TWPD, and PWPD were significantly higher in OPo patients. The largest OPo/Young average percentage differences were found in MMF (41.9%), PWPD (103.5%), and MMPD (64.0%). PWPD was significantly higher (50.7%), while BWPD was significantly lower (16.4%) in OPe than the Young group on average. MMF was found to be significantly lower (27%) in OPo patients compared with OPe group. T1, MMF, TWPD, PWPD, and MMPD values significantly correlated with the total hip DXA T-scores (provided by the patients and only available for OPe and OPo patients). DXA T-score showed the highest correlations with PWPD (R = 0.55) and MMF (R = 0.56) values. TWPD, PWPD, and MMF estimated using the UTE-MRI sequences were recommended to evaluate individuals with OPe and OPo.

Keywords: Magnetic resonance imaging; collagen proton density; cortical bone; magnetization transfer; pore water; ultrashort echo time.

Plain language summary

Ultrashort echo time (UTE) is an MRI technique that can quantify the water and collagen content of cortical bone. Water in the bone can be found residing in pores (pore water) or bound to the bone matrix (bound water). We investigated the differences in water and collagen contents of tibial cortical bone, between female osteopenia patients, osteoporosis patients, and young participants. Bound water and collagen contents were significantly lower in osteoporosis patients than in the young group. Whereas total water and pore water contents were significantly higher in osteoporosis patients. Pore water was significantly higher, while bound water was significantly lower in osteopenia than in the Young group. Collagen content was found to be significantly lower in osteoporosis patients compared with the osteopenia group. The estimated water and collagen contents were significantly correlated with the total hip bone densitometry measures in the patients.

© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research. All rights reserved. For permissions, please email:journals.permissions@oup.com.