Abstract: Objective: To compare the CT findings and iodine concentration between primary gastric lymphoma (PGL) and advanced gastric cancer (AGC), and to evaluate the diagnostic efficacy of dual-source CT in differentiating PGL from AGC. Methods: A total of 50 PGL patients and 50 AGC patients were enrolled. Characteristics of the lesions on CT imaging were recorded, including gastric wall thickness, 'white line' sign of mucosa, sites involved, enhancement degree, and iodine concentration. Results: No significant difference in gastric wall thickness(P=0.874) or sites of stomach involved (P=0.718) were found between PGL and AGC groups. The AGC group had higher positive rate of 'white line' sign of mucosa (64% vs 24%, χ²=16.234, P<0.0001), higher enhancement degree [(45.52±18.0) HU vs (30.72±10.6) HU, P<0.001] and higher iodine concentration [(2.31±0.50) g/mL vs (2.00±0.23) g/mL, P<0.001] than those of PGL group. For diagnosis of AGC, the sensitivity of positive 'white line' sign of mucosa, enhancement ≥34.5 HU and iodine concentration ≥2.25 g/mL were 64%, 76% and 56%, respectively, and the specificity were 76%, 80% and 88%, respectively. Conclusions: The 'white line' sign of mucosa, the enhancement degree, the iodine concentration acquired by dual-source CT are capable of differentiating PGL from AGC. A criterion of iodine concentration ≥2.25 g/mL is recommended for diagnosing AGC. A combined criteria of positive 'white line' sign of mucosa and enhancement ≥34.5 HU in parallel is recommended for the sensitive diagnosis of AGC, with a sensitivity of 90%.

Key words: Primary gastric lymphoma, Advanced gastric Cancer, Differential diagnosis