Résumé
ObjectiveTo study the imaging characteristics of SPN of adenocarcinoma (ASPNs) on 18F-FDG PET/CT.MethodsThe morphological and metabolic features of 35 ASPNs on FDG PET/CT were retrospectively reviewed.SUVmax (SUV) was measured and ΔSUVmax was calculated according to ΔSUVmax =(SUVmax on delay imaging - SUVmax on early imaging)/SUVmax on early imaging × 100％.Statistical analysis was performed by software SPSS 11.5 using t-test,analysis of variance and Fisher exact test.Results( 1 ) Fifteen ASPNs (42.86％,15/35) presented as nodular pattern on FDG PET imaging,while 20 (57.14％,20/35) as lamellar,cloudy or ill-defined patterns.The SUVmax of these ASPNs followed a descending order of nodular,lamellar,cloudy and ill:defined on both early and delay imaging (F =30.696 and 24.758,both P＜0.001).(2)There were 54.29％ (19/35) ASPNs with SUVmax ≥2.5 and 45.71％ (16/35) ASPNs with SUVmax ＜2.5.(3) Of 35 ASPNs,24(68.57％ ) were solid nodules and 11(31.43％) were ground glass nodules with SUVmax =4.54 ±2.69 and 1.30±0.87,respectively (t =-5.234,P ＜O.001 ).(4) The SUVmax of ASPNs on delay FDG imaging (4.22 ±3.52) was significantly higher than that on early imaging (3.49 ±2.72) (t =-4.021,P ＜0.001 ).However,SUVmax was dependent on SUVmax on the early imaging:when SUVmax ≥2.5,ΔSUVmax was positive in 94.74％ (18/19) of ASPNs; while SUVmax ＜2.5,ΔSUVmax was positive in 56.25％ (9/16) of ASPNs (P =0.013).(5) Of 31 ASPNs with cell differentiation data,there were 10/17 well-differentiated ASPNs and 13/14 poorly-differentiated ASPNs with positive ΔSUVmax ( P =0.045 ).The average SUVmax of well-differentiated ASPNs was significantly lower than that of poorly-differentiated ASPNs ( 1.70 ± 1.51 vs 4.91 ± 2.69,t =- 3.951,P ＜ 0.001 ).Conclusions The morphological and metabolic features of ASPNs are diversified.It is common for ASPN to present with SUVmax ＜ 2.5.ΔSUVmax may be helpful for differentiating malignant from benign SPNs.