ABSTRACT
<p><b>OBJECTIVE</b>To investigate the diagnostic value of contrast-enhanced ultrasonography (CEUS) in preoperative T-staging of gastric cancer.</p><p><b>METHODS</b>A sulfur hexafluoride-filled microbubble ultrasound contrast agent and a continuous real-time imaging technique of contrast pulse sequencing were used. Normal gastric wall was examined by CEUS in 8 healthy volunteers and the results were compared with the findings on multislice computed tomography. Sixty-two patients with gastric cancer proved by biopsies who received preoperative CEUS examination were involved in this study, and the CEUS result was compared with postoperative pathological findings.</p><p><b>RESULTS</b>The normal gastric wall presented a one-layer structure in the portal venous phase and a three-layer structure in the arterial and equilibrium phase including a slightly hyper-enhanced inner layer, a hypo-enhanced intermediate layer, and a markedly hyper-enhanced outer layer, which corresponded histologically to the mucosal, submucosal, and muscular-serosal layer, respectively. The accuracy of transabdominal ultrasonography and CEUS in determining the T stage of gastric cancer was 72.9% and 88.1% respectively, and the difference was statistically significant (chi(2)=4.37, P=0.036).</p><p><b>CONCLUSIONS</b>CEUS shows the normal gastric wall as a one- or a three-layer structure, which provides a theory base for CEUS in preoperative T-staging of gastric cancer. CEUS is a useful diagnostic method for preoperative T-staging of gastric cancer.</p>