Tissue harmonic imaging: Is it a benefit for bile duct sonography?

OBJECTIVE. Our purpose was to compare tissue harmonic imaging with conventi onal sonography of the biliary tract. SUBJECTS AND METHODS. Eighty patients with suspect biliary disease had conv entional sonography and tissue harmonic imaging with an ATL 3000 or 5000 sc anner in a 6-month interval. Final diagnoses included malignant biliary obs truction (n = 30), choledocholithiasis (n = 16), sclerosing cholangitis (n = 4), normal or nonobstructed ducts (n = 16), and miscellaneous conditions (n = 14). Similar images were taken with each technique in terms of project ion, field of view, focal zone selection, and evidence of disease. Two sepa rate observers blinded to patient data and technique reviewed and graded im ages individually for the appearance of the lumen of the bile ducts. the le ngth of the visible duct, the appearance of the duct wall, the presence of any intraluminal masses, and the appearance of associated acoustic shadows. Images were graded from zero to 3, with 3 being the best. RESULTS. The median of the 546 tissue harmonic images was one grade higher than the median for the corresponding conventional images (p < 0.0001). Imp rovements with tissue harmonic imaging included better sharpness of the duc t walls (p < 0.01). a clearer lumen (p < 0.0001), identification of a longe r length of the common bile duct (p < 0.0001), and improved detection of in traluminal masses (p < 0.006). Acoustic shadows were better defined and bla cker with tissue harmonic imaging (p < 0.007). CONCLUSION. Improvement in contrast and reduction of side lobe artifacts wi th tissue harmonic imaging enhance visualization of the biliary ducts. Tiss ue harmonic imaging is now our routine technique for bile duct examination.