[Differential Diagnostic Value of ¹⁸F-FDG PET/CT Imaging in Multiple Myeloma and Bone Metastases]

To investigate the imaging characteristics of ¹⁸F-FDG positron emission computed tomography (¹⁸F-FDG PET/CT) in multiple myeloma (MM) patients and to analyze its application value in MM and bone metastases.

A retrospective analysis was made on MM patients (n=72) and bone metastases patients (n=50) admitted to Hainan Western Central Hospital from January 2017 to March 2019. All patients underwent ¹⁸F-FDG PET/CT examination. The distribution of lesions, bone destruction, maximum standardized uptake (SUV_max) and metabolic homogeneity were analyzed in both groups.

More than 80% of MM and bone metastases involved thoracic bone, spine and pelvis, followed by limbs. MM was more common in the lesions of thoracic bone and skull than those in bone metastases, the difference was statistically significant (P＜0.05). The majority of MM patients presented osteolytic bone destruction (97.2%), mostly showing "insect-like phagocytic pattern", so the bone showed dilated changes, and osteogenic changes were rarely seen (2.8%). Osteolytic bone destruction accounted for 74.0% in patients with bone metastatic tumor, presenting "focal" appearance more often, and osteogenic changes accounted for 26.0%. Osteolytic bone destruction in patients with MM was significantly higher than that in patients with bone metastases（χ²=14.757，P＜0.05）. The SUV_max of MM (4.25±2.16)was significantly lower than that of bone metastases (7.84±3.25) (t=6.830, P＜0.05). Diffuse mild uptake of ¹⁸F-FDG was more common in patients with MM, and heterogeneous high uptake of ¹⁸F-FDG was more common in patients with bone metastasis, the difference was statistically significant (P＜0.05).

¹⁸F-FDG PET/CT examination is helpful to acquire the imaging features of bone structure and metabolic changes, and shows an important clinical value in the differential diagnosis of MM and bone metastases.