RÉSUMÉ
Purpose To evaluate the value of 18F-FDG PET/CT in the diagnosis of intradural metastasis.Materials and Methods The imaging data of patients with clinical suspicion of intraspinal metastasis who underwent 18F-FDG PET/CT and MRI of the whole spinal cord from October 2010 to April 2022 in Jiangxi Provincial People's Hospital were retrospectively analyzed.Visual evaluation was performed on the metabolic activity of the lesion and the maximum standard uptake value(SUVmax)was measured.The sensitivity,specificity and accuracy of 18F-FDG PET/CT in the diagnosis of intradural metastases were analyzed,and the efficacy of SUVmax in the diagnosis of intradural metastases was analyzed by receiver operating characteristic curve.Results Among 135 patients suspected of intraspinal metastasis,18 patients were diagnosed with intradural metastases,80 patients had other lesions and 37 patients had no metastasis.Among the 18 cases of intradural metastases,13 cases were leptomeningeal metastases,2 cases were intramedullary metastasis,3 patients had both leptomeningeal and intramedullary metastasis.Metastases appear as nodular(10 cases)or patchy(6 cases)increased fluorodeoxyglucose uptake,corresponding to paramedullary or intramedullary nodules or spinal cord swelling on CT.18F-FDG PET/CT showed more lesions than MRI,including subcentimeter foci.Based on patients,the sensitivity,specificity and accuracy of 18F-FDG PET/CT in diagnosing intradural metastasis were 88.9%,89.2%and 89.1%,respectively.The receiver operating characteristic curve analysis showed that when SUVmax was 2.45,Youden index was the largest,corresponding to 88.2%sensitivity and 75.7%specificity.Conclusion 18F-FDG PET/CT may be an optional imaging modality for diagnosis of intradural metastases.Most of the intradural metastases present with focal hypermetabolic lesions.SUVmax can be used as a valuable parameter in the diagnosis of intradural metastases.