Evaluation of hybrid PET/CT gastrography in gastric cancer

With the recent advances in multidetector-row CT, a fusion of functional PET with three dimensional (3D) CT gastrography may provide enhanced diagnostic capability and help surgeons during preoperative planning. The diagnostic value of hybrid PET/CT gastrography was compared with that of conventional PET/CT alone in gastric cancer staging.

Patients with gastric cancer (n = 101) confirmed by endoscopic biopsy specimens underwent conventional PET/CT and regional PET with contrast enhanced CT, followed by gastrectomy with lymphadenectomy at our institution from November 2007 to November 2008. These images were fused into a hybrid PET/CT gastrography using the cardiac IQ fusion software. Conventional PET/CT and hybrid PET/CT gastrography were evaluated for staging of gastric cancer. After gastrectomy, these were compared with pathologic reports respectively.

Gastric cancer was diagnosed as 50 early gastric cancer (EGC) and 51 advanced gastric cancer (AGC) on pathologic examination. In EGC, hybrid PET/CT gastrography and PET/CT identified 36 (72%) and 7 (14%) tumours, respectively. Hybrid PET/CT gastrography correctly delineated the subtype of 25 EGC. In AGC, all 51 (100%) tumours were identified on the hybrid PET/CT gastrography compared to 39 (76.5%) tumours on PET/CT. Hybrid PET/CT gastrography correctly classified the morphology of 42 AGC using the Bormann classification. Additionally, depth of invasion was correctly presented in 38 of 51 AGC. Hybrid PET/CT gastrography for regional lymph node (LN) metastasis in the EGC and AGC showed the sensitivity of 75% and 83.9%, and specificity 90.5% and 55%, respectively.

Hybrid PET/CT gastrography is the more intuitive and comprehensive method for the preoperative evaluation of gastric cancer than conventional PET/CT.