Application of bone scintigraphy T/NT ratio and diffusion-weighted imaging ADC value in the diagnosis of solitary spinal bone metastases

QIN Zhengyan; WEI Haofeng

doi:10.3969/j.issn.1674-666X.2025.05.003

Abstract：Objective To investigate the application value of bone scintigraphy target/nontarget ratio(T/NT ratio,the radioactive uptake ratio of metastatic lesions to normal bone tissue)and diffusion-weighted imaging(DWI)apparent diffusion coefficients(ADC)in the diagnosis of solitary spinal bone metastases.Methods A total of 123 patients diagnosed with malignant tumors and solitary bone lesions between January 2021 and December 2024 at Zhengzhou Orthopedic Hospital were selected,and their clinica data were analyzed retrospectively.Based on the pathological examination results and comprehensive imaging findings,46 patients with confirmed spinal bone metastasis were included in the bone metastasis group,while the remaining 77 cases diagnosed by benign lesions were included in the benign lesion group.All patients underwent MRI and bone scintigraphy,signal characteristics of patients in two groups were recorded,and changes in ADC values and T/NT ratios were analyzed to assess their diagnostic performance for spinal bone metastases.Results There were no significant differences between the two groups in clinical symptoms(low back pain,skeletal pain,neurological symptoms,pathological fractures,spinal deformities)and lesion locations(cervical,thoracic,lumbar-sacral spine)(P>0.05).In T1WI sequence,the proportion of equal or low signal and high signal in both groups did not differ significantly(P>0.05).In T2WI sequence,the high-signal proportion in the bone metastasis group was significantly higher than that in the benign lesion group(P<0.05).In DWI sequence,the high-signal proportion in the bone metastasis group was also higher than that in the benign lesion group(P<0.05).ADC value and T/NT ratio of the affected vertebrae in the bone metastasis group were significantly higher than those in the benign lesion group(P<0.05),while there was no significant difference in the ADC value of the adjacent normal vertebrae between the two groups(P>0.05).According to receiver operating characteristic curve analysis,ADC value and T/NT ratio of the affected vertebrae were demonstrated high diagnostic efficiency for bone metastasis,with area under curve of 0.847 and 0.834,respectively.The combined diagnostic AUC values of both parameters was 0.900,which was higher than the AUC avalue of separate detection.Conclusion The high-signal proportion in T2WI and DWI sequence of the bone metastasis group are higher than those of the benign lesion group.Additionally,ADC value and T/NT ratio of the affected vertebrae in the bone metastasis group are higher than those of the benign lesion group,and the combination of ADC value and T/NT ratio provides higher diagnostic value.