To investigate the diagnostic value of 2-[fluorine 18] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET-CT) imaging in the breast imaging reporting and data system (BI-RADS) ultrasound category 3-5 lesions.

According to the inclusion and exclusion criteria, this retrospective study involved 76 patients with BI-RADS category 3-5 lesions (77 lesions) in the First Medical Center of PLA General Hospital from January 2012 to October 2018. All patients underwent ¹⁸F-FDG PET/CT and ultrasound examination. The diagnostic efficiency of the two methods was compared. The max standard of uptake value (SUVmax) was compared between benign and malignant lesions in BI-RADS category 3-5 lesions by independent sample t test. SUVmax was compared among different subcategory by one-way ANOVA, and the Tamhane method was used for pairwise comparison. With pathological result as golden standard, the ROC curve was drawn and the area under the curve (AUC) was calculated in the Medcalc software. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of two methods were compared by paired χ² test and χ² test.

Among BI-RADS category 3-5 lesions, SUVmax of malignant lesions was significantly higher than that of benign lesions (7.6±4.5 vs 1.8±0.8, t=8.30, P<0.001). Among BI-RADS category 4 lesions, SUVmax of malignant lesions was significantly higher than that of benign lesions (6.9±4.5 vs 1.6±0.7, t=-5.552, P<0.001). SUVmax of BI-RADS category 3, 4 and 5 lesions was 2.2±1.3, 5.2+ 4.2 and 10.1+ 5.5, indicating a significant difference and an increasing trend (F=14.68, P<0.001). ROC curve analysis showed that SUVmax AUC was 0.931(95%CI: 0.877-0.984)for BI-RADS category 3-5 lesions and 0.789(95%CI: 0.684-0.894)for BI-RADS ultrasound, indicating a significant difference (Z=3.044, P=0.002). The cut off value of SUVmax determined by the maximum Yoden index is 3.3. The specificity and positive predictive value of SUVmax were 100%(23/23) and 100%(44/44), significantly higher than those of BI-RADS ultrasound [43.5%(10/23) and 79.7%(51/64); P<0.001; χ²=10.161, P=0.001]. The sensitivity of SUVmax showed no significant difference compared with BI-RADS ultrasound [81.5%(44/54) vs 94.4%(51/54), P=0.065].

The diagnostic efficiency of ¹⁸F-FDG PET / CT is higher than that of BI-RADS ultrasound in BI-RADS category 3-5 lesions, so ¹⁸F-FDG PET / CT is effective for differentiated diagnosis of breast benign and malignant lesions. In BI-RADS ultrasound category 4 lesions, SUVmax was helpful to judge the lesions of ultrasound subcategory.