Double contrast-enhanced ultrasonography in the detection of periampullary cancer: Comparison with B-mode ultrasonography and MR imaging.

PURPOSE: To investigate the value of double contrast-enhanced ultrasonography (DCEUS) in the detection of periampullary cancer.

MATERIALS AND METHODS: Ninety-nine patients with surgery or biopsy-proven periampullary cancer who underwent both DCEUS and magnetic resonance imaging (MRI) examinations before operation were enrolled in our study. DCEUS in which intravenous microbubbles were used in combination with oral contrast agent and MRI were performed preoperatively to make a detection diagnosis of periampullary cancer. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of DCEUS, B-mode ultrasonography (BUS) and MRI were calculated and compared. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of BUS, DCEUS and MRI in the detection. Stratified analyses were performed for different pathological types and different sizes of periampullary lesions. The inter- and intra-observer reliability of DCEUS for cancer detection was also investigated.

RESULT: There were no significant differences in sensitivity, specificity, PPV, NPV or accuracy between DCEUS and MRI (all P>0.05). ROC analysis showed that the accuracy of DCEUS or MRI was higher than that of BUS (P<0.001), while no significant differences were noted in the accuracy between DCEUS and MR. In the 76 cases of periampullary cancer, DCEUS appeared to be superior to BUS for ampullary carcinoma, duodenum carcinoma and for lesions with an average diameter of less than 3cm. DCEUS appeared equal to BUS in other groups. No significant differences were noted between DCEUS and MRI in the stratified analysis. A considerably well agreement between DCEUS and MRI was obtained using Kappa analysis (k=0.649, P<0.001). The intra- and inter-observer reproducibility were both good for detection of periampullary cancer by DCEUS, with a Kappa values of 0.783 (P<0.01) and 0.732 (P<0.01), respectively.

CONCLUSION: DCEUS provides an available and useful imaging modality in the detection of periampullary cancer. This technique can aid in displaying the invisible periampullary region in BUS and may also become an effective supplemental method to MRI.