Feasibility of using double-echo chemical shift imaging to monitor bone mass change in aged patients with lumbago: a pilot study

Background: For aged patients with lumbago, monitoring bone mass change is of great importance for the early diagnosis of osteoporosis.The present study aimed to evaluate the feasibility of using the double-echo chemical shift imaging (CSI) to detect bone mass change in aged population with lumbago. We calculated chemical shift rate (CSR) from double-echo CSI data, and investigated whether CSR correlate to bone mass change. Methods: Two-hundred patients (aged from 60 to 70) with lumbago were included in the study. Each subject accepted a lumbar MR examination, for which the ordinary spin echo T1-Weigthed sequence was modified to the double-echo imaging. By doing so, in-phase and out-phase images could be obtained simultaneously with one acquisition. The bone mineral density (BMD) was measured with digital X-ray radiogrammetry (DXR) at the non-dominant hand. Then all subjects were grouped according to their T-value (normal bone mass group, T-value > -1.0; abnormal bone mass group T-value ≤ -1.0). The CSR were calculated based on the signal intensity (SI) measured respectively at the 3 rd – 5 th lumbar vertebrae. The association of CSR with BMD was investigated, as well as the impact of other factors on BMD. Results: Patients with normal and abnormal bone mass showed significant difference in CSR (P = 0.008), that positively correlated with T-value (r = 0.281, P ＜ 0.001) and negatively correlated with the diagnosis of abnormal bone mass (B = - 3.02, P = 0.010). Furthermore, the risk of abnormal bone mass increased by 4.9% for each unit decrease in CSR. Additionally, females were more likely to have abnormal bone mass than males (P = 0.017), while the patients who had type 2 diabetes was determined to undergo 3.25-time risk to have abnormal bone mass, compared to those who did not have. Conclusions: CSR could be used to predict the bone mass loss in elderly patients with lumbago. Our study provides a more economical solution to monitor bone mass lose in elderly patients who complained lumbago and required lumbar MR imaging. And among such patients, the double-echo CSI is highly recommended to those who have type 2 diabetes.