Objective To investigate the clinical value of 99Tcm-methoxyisobutylisonitrile (MIBI) double-phase imaging in differential diagnosis of bone lesions in tumor patients,which was indefinite in 99Tcm-methylene diphosphonate (MDP) bone imaging,and evaluate the correlation between 99Tcm-MIBI imaging and chemotherapy efficacy.Methods Fifty-two tumor patients (23 males,29 females,mean age 58 years) with bone isolated lesions(≤3) found by 99Tcm-MDP bone scintigraphy was enrolled from June 2014 to November 2015.Since the results of 99Tcm-MDP imaging were indefinite,99Tcm-MIBI double-phase (10 min and 30 min after injection of 99Tcm-MIBI) SPECT/CT imaging was then performed within 1 week.The final diagnosis was made according to results of more than two imaging modalities (CT,MRI,PET/CT) and/or follow-up (≥6 months).The diagnostic efficacy of 99Tcm-MIBI SPECT/CT imaging was calculated.The clinical dataof chemotherapy were also collected.Patients with bone metastasis were grouped as the treatment response.Retention index (RI) of metastatic lesions was calculated and compared between different groups using two-sample t test.The relationship between RI and chemotherapy efficacy was investigated by Spearman correlation analysis.Results A total of 12 benign lesions and 84 malignant lesions were eventually diagnosed.The sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV) and Youden index of 99Tcm-MIBI imaging were 96.43％(81/84),83.33％(10/12),97.59％(81/83),76.92％(10/13),and 0.80,respectively.The RI was statistically different between complete remission (CR)+partial remission (PR) group and stable disease (SD) + progressive disease (PD) group:-0.142± 0.036 vs-0.384± 0.067 (t =2.367,P＜0.05).The RI of 99Tcm-MIBI in bone metastases was positively correlated with the chemotherapy efficacy (rs =0.78,P＜0.01).Conclusions 99Tcm-MIBI imaging is helpful in differential diagnosis of bone lesions with indefinite diagnosis by 99Tcm-MDP bone imaging in tumor patients.99Tcm-MIBI RI of bone metastasis may predict the therapeutic response of chemotherapy efficacy.

The immune-stromal cell interactions play a key role in health and diseases.In periodontitis,the most prevalent infectious disease in humans,immune cells accumulate in the oral mucosa and promote bone destruction by inducing receptor activator of nuclear factor-κB ligand(RANKL)expression in osteogenic cells such as osteoblasts and periodontal ligament cells.However,the detailed mechanism underlying immune-bone cell interactions in periodontitis is not fully understood.Here,we performed single-cell RNA-sequencing analysis on mouse periodontal lesions and showed that neutrophil-osteogenic cell crosstalk is involved in periodontitis-induced bone loss.The periodontal lesions displayed marked infiltration of neutrophils,and in silico analyses suggested that the neutrophils interacted with osteogenic cells through cytokine production.Among the cytokines expressed in the periodontal neutrophils,oncostatin M(OSM)potently induced RANKL expression in the primary osteoblasts,and deletion of the OSM receptor in osteogenic cells significantly ameliorated periodontitis-induced bone loss.Epigenomic data analyses identified the OSM-regulated RANKL enhancer region in osteogenic cells,and mice lacking this enhancer showed decreased periodontal bone loss while maintaining physiological bone metabolism.These findings shed light on the role of neutrophils in bone regulation during bacterial infection,highlighting the novel mechanism underlying osteoimmune crosstalk.