Standardized Uptake Values of 99mTc-MDP in Normal Vertebrae Assessed Using Quantitative SPECT/CT for Differentiation Diagnosis of Benign and Malignant Bone Lesions

Background: Quantitative bone SPECT/CT is useful for disease follow up and inter-patient comparison. For bone metastatic malignant lesions, spine is the most commonly invaded site. However, Quantitative studies with large samples size investigating all the segments of normal cervical, thoracic and lumbar vertebrae are seldom reported. This study was to evaluate the quantitative tomography of normal vertebrae using 99m Tc-MDP with SPECT/CT to investigate the feasibility of standardized uptake value (SUV) for differential diagnosis of benign and malignant bone lesions. Methods: : A retrospective study was carried out involving 221 patients (116 males and 105 female) who underwent SPECT/CT scan using 99m Tc-MDP. The maximum SUV (SUV max ), mean SUV (SUV mean ) and CT values (Hounsfield Unit, HU) of 2416 normal vertebrae bodies, 157 benign bone lesions and 118 malignant bone metastasis foci were obtained. The correlations between SUV max and CT values, age, height, weight of normal vertebrae were analyzed. Statistical analysis was performed with data of normal, benign and malignant groups corresponding to same sites and gender. Results: : The SUV max and SUV mean of vertebrae in males were markedly higher than those in females (P<0.0009). The SUV max of each vertebral segment showed a strong negative correlation with CT values in both males and females (r=-0.89 and -0.92, respectively; P<0.0009). The SUV max of vertebrae also showed significant correlation with weight and height in males (r=0.4, P<0.0009; r=0.28, P=0.005), and significant correlation with weight in females (r=0.32, P=0.009). The SUV max of normal group, benign bone lesion group and malignant bone metastasis foci group showed statistical differences in both males and females. Conclusion: Our study evaluated SUV max and SUV mean of normal vertebrae, benign bone lesion and malignant bone metastasis foci with a large sample population. Preliminary results proved the potential value of SUV max in differentiation benign and malignant bone lesions. The results may provide a quantitative reference for clinical diagnosis and the evaluation of therapeutic response in vertebral lesions.