PT - JOURNAL ARTICLE AU - Pavel Gelezhe TI - Сomparison of the accuracy of 18F-FDG PET/CT and PET/MRI in attenuation correction and tumor size assessment in breast cancer DP - 2020 May 01 TA - Journal of Nuclear Medicine PG - 3124--3124 VI - 61 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/61/supplement_1/3124.short 4100 - http://jnm.snmjournals.org/content/61/supplement_1/3124.full SO - J Nucl Med2020 May 01; 61 AB - 3124Objectives: Breast cancer imaging is the most promising area for PET/MRI using. Optimized study protocols offer the advantage of both modalities, reducing examination time for patients and reducing radiation exposure compared to PET/CT. The purposes of our study were:- to evaluate the accuracy of attenuation correction of breast 18F-FDG PET/MRI in comparison with 18F-FDG PET/CT;- to compare the size of the primary tumor with sequential performance of breast 18F-FDG PET/CT and 18F-FDG PET/MRI. Methods and Materials: The study group included 21 patients with breast cancer who underwent breast 18F-FDG PET/MRI and 18F-FDG PET/CT with an average interval 43 minutes. The average age of the third group was 56.4±11.1 years. The average interval between studies was 43 minutes.SUVmax, SUVmin and SUVmean values were determined on CT and MR attenuation correction maps by manually selecting the region of interest (ROI). According to MRI with dynamic contrast enhancement and native CT the largest tumor size in the axial plane was determined; in the case of multifocal lesion, the largest tumor node was measured. Results: - no statistically significant (P<0.05) differences between the level of metabolism according to various attenuation correction methods;- in three patients (14.3%) MRI-detected tumors were not detected by CT without intravenous contrast enhancement;- a statistically significant (P<0.001) difference in the mean values ​​of the largest tumor size was revealed (pic. 1: statistically significant (P<0,001) difference between measurements of tumor sizes using PET/CT and PET/MRI; and 2: Bland-Altman plot demonstrates no systematic difference between measurements of tumor size using PET/CT and PET/MRI). Conclusions: Breast 18F-FDG PET/MRI is not inferior to 18F-FDG PET/CT in assessing the level of tumor metabolism and has the advantage of determining the size of the tumor.