Lumbar Spine Bone Mineral Density Measurement: Comparison of Dual-Energy X-Ray Absorptiometry and Fat Content Evaluation by Dixon Chemical Shift MRI

Fei-Xia Chang; Dun-Hui Fan; Gang Huang; Jian-Hong He

doi:10.2147/IJGM.S370814

Lumbar Spine Bone Mineral Density Measurement: Comparison of Dual-Energy X-Ray Absorptiometry and Fat Content Evaluation by Dixon Chemical Shift MRI

Int J Gen Med. 2022 Aug 4:15:6415-6424. doi: 10.2147/IJGM.S370814. eCollection 2022.

Authors

Fei-Xia Chang¹, Dun-Hui Fan², Gang Huang³, Jian-Hong He²

Affiliations

¹ Radiology Department, Dunhuang City Hospital, Dunhuang, 736200, People's Republic of China.
² Department of General Surgery, Dunhuang City Hospital, Dunhuang, 736200, People's Republic of China.
³ Radiology Department, Gansu Provincial People's Hospital, Lanzhou, 730000, People's Republic of China.

Abstract

Background: To assess whether the fat signal intensity and fat fraction (FF) of the lumbar vertebrae as measured on the Dixon chemical shift magnetic resonance imaging (MRI) technique can be correlated with the lumbar vertebra bone mineral density (BMD) measured using dual-energy X-ray absorptiometry (DXA).

Methods: Forty-five patients were retrospectively collected, and 180 lumbar vertebral bodies (L1-L4) were included. All patients underwent DXA and MRI examinations of the lumbar spine. Taking the T value of DXA as the gold standard and using the diagnostic criteria of the World Health Organization: T score ≥ -1.0SD as normal, -1.0 ~ -2.5SD as osteopenia, and ≤ -2.5SD as osteoporosis. Meanwhile, the signal intensity on T2WI was measured, and FF of L1-L4 vertebral bodies was calculated on MRI images. Bone marrow fat FF calculation formula: FF = [Mfat/(Mfat + Mwater)] × 100% (Mwater and Mfat refer to the total pixel signal intensity value of the region of interest in water image and lipid image, respectively). Finally, the association of signal intensity and FF with DXA was evaluated.

Results: Totally 180 vertebral bodies in 45 patients were enrolled. According to the T value, they were divided into the normal group (n = 70), osteopenia group (n = 40), and osteoporosis group (n = 70). The fat signal intensity of the normal group, osteopenia group, and osteoporosis group were 96.6 ± 21.8, 154.5 ± 48.7, 216.3 ± 92.6, and the FF were 30.1 ± 6.2%, 52.6 ± 7.6%, 77.5 ± 7.9%, respectively. Among the three groups, the lumbar T2 fat signal intensity and FF had statistical differences (P < 0.01). Besides, the lumbar fat signal intensity and FF were negatively related to DXA (r =-0.65 and -0.93, P < 0.01).

Conclusion: The fat content calculated using the Dixon chemical shift MRI had an inverse relation with BMD. Moreover, the Dixon chemical shift MRI might provide complementary information to osteoporosis-related research fields.

Keywords: fat fraction; magnetic resonance; osteoporosis; vertebral body signal intensity; water-lipid separation technology.

Grants and funding

This work was supported by the Science-Technology Foundation for Middle-aged and Young Scientist of Gansu Province, China. [Grant Number 17JR5RF350].