Abstract:
Objective To analyze the features and application value of 18F-FDG PET/CT in detecting intraocular metastases.
Methods A total of 53 patients with intraocular metastasis (54 eyes, including 1 case of binocular metastasis) diagnosed by pathology or clinical assessment at the Beijing Hospital and Beijing Tongren Hospital, Capital Medical University from March 2011 to February 2019 were enrolled in this retrospective study. The patients included 23 males and 30 females aged 22–73(52.7±11.6) years. All patients underwent 18F-FDG PET/CT, and the features and parameters of the resulting images, including maximum (SUVmax) and average (SUVmean) standardized uptakes, were analyzed. The value of PET/CT for the detection of primary tumors and metastases was then assessed. Analysis of variance was used to compare the data of multiple groups, and Pearson's correlation analysis was used to determine correlations.
Results Intraocular metastases showed a variety of unique CT features, the most common of which was spindle-like soft tissue shadows. No significant linear relationship between the CT value and SUVmax or SUVmean (both r=−0.252; both P=0.088) among 47 cases of measurable intraocular metastasis was detected. SUVmax and SUVmean were positively correlated with their long, short, upper, and lower diameters (r=0.631–0.791; all P=0.000). The detection rate of the primary focus by PET/CT among 43 patients with no prior history of cancer was 97.7% (42/43). Among the cases of intraocular metastasis, 36 originated from lung cancer, 2 were from breast cancer, 1 was from esophageal cancer, 1 was from gastric cancer, 1 was from nasopharyngeal cancer, and 1 was from prostate cancer. PET/CT revealed 51 patients (51/53, 96.2%) with more than two metastatic lesions, 81.1% (43/53) with lymph node metastasis, and 79.2% (42/53) with bone metastasis. However, PET/CT may result in false negative findings for small intraocular and brain metastases.
Conclusions Intraocular metastases exhibit a variety of distinct CT features, and only the SUV is related to the tumor size. 18F-FDG PET/CT is useful for the diagnosis of intraocular metastases, exploration of primary tumors, and discovery of metastases in other sites.