Double contrast-enhanced ultrasonography evaluation of preoperative Lauren classification of advanced gastric carcinoma

Abstract

Introduction: The clinical value of double contrast-enhanced ultrasonography (DCUS) in determining the Lauren classification of advanced gastric carcinoma needed investigation.

Material and methods: Fifty-eight patients with gastric cancer proved by endoscopic biopsy underwent preoperative DCUS examination in which an oral contrast agent was combined with an intravenous agent, and the findings were compared with the postoperative pathological findings using haematoxylin-eosin and Alcian Blue-Periodic Acid Schiff (AB-PAS) staining.

Results: Of 58 patients, 34 (59%) were the intestinal type and 24 (41%) the diffuse type on pathological examination of resected specimens. Among intestinal type patients, 30 (88%) showed homogeneous vascular enhancement and 4 (12%) heterogeneous enhancement with the "sandwich" pattern in 2 patients (50%) and "barrier" pattern in 2 patients (50%). In the diffuse type, 22 of 24 patients (92%) enhanced heterogeneously, with stippled and peripheral enhancement in 9 (41%), the "sandwich" pattern in 8 (36%) and "barrier" pattern in 5 (23%). Two of 24 patients (8%) with the diffuse type enhanced homogeneously. The proportion of heterogeneous enhancement was significantly different between the 2 subtypes of tumour (p = 0.0001). The sensitivity and specificity of heterogeneous enhancement in diagnosing the diffuse type of advanced gastric cancer were 92% and 88%, respectively. Youden's index was 0.8.

Conclusions: Double contrast-enhanced ultrasonography is a new and useful method to determine Lauren classification in patients with gastric carcinoma.

Keywords: Lauren classification; contrast; gastric carcinoma; microbubbles; ultrasonography.

Figure 1

The effect of the oral contrast agent. A) Following swallowing of the Xinzhang^® oral contrast agent, the gastric lumen appears as a mid-grey, homogeneous region that acts as an acoustic window and improves visualization of the inner wall (arrows). This was a normal patient. B) In another patient, a gastric carcinoma is clearly displayed as a hypoechogenic region (between two cursors) after taking the Xinzhang^® oral contrast agent

Figure 2

Intestinal type of gastric carcinoma. A) The tumour is displayed as a hypoechoic mass (between two cursors) after taking the Xinzhang^® oral contrast agent. B) This tumour enhanced homogeneously with no signal defects during the early arterial phase (white arrow). C) The tumour proved to be a well differentiated intestinal type of carcinoma (×200 HE). D) On AB-PAS staining, the acid mucus took up the blue dye (×200) STO - stomach

Figure 3

Diffuse type of gastric carcinoma. A) In another patient, a gastric carcinoma was again clearly displayed (between two cursors) as an echo-poor region after taking the Xinzhang^® oral contrast agent. B) The tumour enhanced heterogeneously during the early arterial phase with stippled and peripheral enhancement (white arrows). C) This carcinoma was poorly differentiated; the blue arrows show the signet-ring cells (×200 HE). D) AB-PAS staining shows the neutral mucus (×200)

Figure 4

Diffuse type of gastric carcinoma showing the sandwich pattern. A) The oral contrast agent highlights the hypoechogenic tumour (between the cursors). B) During the early arterial phase of i.v. enhancement the tumour enhanced hetero geneously with the sandwich pattern (white arrows)

Figure 5

Diffuse type of gastric carcinoma showing the barrier pattern. A) The echopoor gastric carcinoma is clearly displayed (white arrows) using oral contrast ultrasonography. B) This lesion of the diffuse type enhanced heterogeneously during the early arterial phase with the barrier pattern (white arrows) STO - stomach