Acoustic radiation force impulse imaging of focal pancreatic lesions

Purpose: To evaluate the application of acoustic radiation force impulse (ARFI) elastosonography with virtual touch tissue quanti cation for the characterization of focal pancreatic lesions. Material and Methods: 120 patients with pancreatic lesion (64/120 solid; 36/120 cystic) were prospectively enrolled. 5 measurements were performed on each lesion with virtual touch tissue quanti cation. Different shear wave speed cut-off were chosen to identify ductal adenocarcinomas. Lesions with >1 measurement (analysis method 1) or >2 measurements (analysis method 2) above each cut-off were calculated. Sensitivity, speci city, positive and negative predictive values and accuracy of both methods were calculated. The evaluation of cystic lesions aimed to differentiate serous (benign) from mucinous (potentially malignant) lesions. The non-numerical value “XXXX/0” identi es serum. To identify mucinous content, two analysis methods were chosen: >2 measurements with numerical result (analysis method 3) or prevalence of numerical values upon all measurements (analysis method 4). Results: Analysis method 1 with a 2.00 m/s cut-off has the highest accuracy for adenocarcinoma identi cation (78%); 100% speci city and positive predictive value are obtained with a 4.00 m/s cut-off. Sensitivity, speci city, positive and negative predictive values, and accuracy for cystic lesions are respectively: 69%, 54.2%, 64.5%, 59.1%, 62.3% for analysis method 3 and 48.3%, 83.3%, 77.8%, 57.1%, 64.1% for analysis method 4. Conclusion: ARFI imaging with virtual touch tissue quanti cation can have a role in the non-invasive characterization of pancreatic lesions.