Role of 2ND generation contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of biliary duct diseases

The differential diagnosis of biliary duct lesions is sometime difficult to establish with need to perform several non invasive or invasive (ERCP) procedures. We report our preliminary experience with the 2nd generation contrast-enhanced ultrasonography (CEUS) in the evaluation of biliary duct diseases.

In a three-month period, 15 patients (9 male, with age ranging from 65–87yrs) underwent ultrasonography (US) for abdominal pain and jaundice of unknown origin. All but two had also abnormal citolytic and cholestatic liver function tests. In all of them, conventional US showed dilation of secondary and/or main bile ducts (MBD). Five patients showed a hyper-isoechoic (group A) and one a hypoechoic (group B) mass in MBD without shadow cone. Seven patients had a hyperechoic mass with shadow cone (group C). In the remaining 2 patients (group D) US didn\'t find any mass inside the MBD. All patients underwent CEUS by injecting 2.4 mL of 2nd generation contrast agent (Sonovue – Bracco, Italy) followed by 10 mL of saline. CEUS examination lasted approximately 3 minutes; results were compared to that of ERCP performed after the US evaluation.

After contrast injection, different US patterns were documented. In patients of groups A and B, 5 out of 6 lesions showed an early hypervascular pattern after 13–20s, followed by a phase iso-hypovascular pattern, suggestive of neoplasia. In a single patient, the biliary mass did not show contrast enhancement thus suggesting dense bile or microstones. In patients of group C, the masses did not show contrast enhancement suggesting biliary stones. In both patients of group D, however, a mass was detected in the distal tract of MBD with an early hyperperfusion and a late isoperfusion pattern, similarly to that of patients of group A and B. The ERCP evaluation confirmed the diagnosis of neoplasia in the 5 patients of group A and B and in the 2 patients of group D (3 ampulloma and 4 cholangiocarcinoma). In the remaining patients (1 of group A and all patients of group C), the presence of stone or dense bile was confirmed by ERCP. Compared to ERCP, CEUS showed a sensitivity and specificity of 100%.

These results, although preliminary and in a small series, demonstrate that CEUS is a promising non-invasive technique in differentiating non-neoplastic from neoplastic biliary duct lesions