Four-dimensional volume contrast ultrasound imaging of the gallbladder compared with tissue harmonic imaging: preliminary experience.

Comparison of volume contrast US imaging with tissue harmonic imaging for the evaluation of gallbladder lesions and determination of the adequate slice thickness in volume contrast US imaging were performed. Forty-one patients who had gallbladder lesions (polyps in 26, stones in 12, and sludge in 3) were enrolled in our study. A Voluson 730 Expert US scanner was used throughout. Volume contrast US imaging with slice thicknesses of 3, 5, 10 and 15 mm and tissue harmonic imaging of the gallbladder were obtained. Two abdominal radiologists reviewed the masked images and graded by consensus these images using a five-point scale [from grade 1, (best), to grade 5, (worst)], based on the sharpness of the anterior gallbladder wall, internal artifact, lesion conspicuity and acoustic shadowing from stone. Volume contrast US imaging with thin slice thicknesses (3 or 5 mm) was judged superior to both tissue harmonic imaging and with thick slice thicknesses (10 or 15 mm), with respect to the sharpness of the anterior wall and lesion conspicuity ( P<0.001). In terms of internal artifact, volume contrast imaging with thin slice thicknesses was significantly superior to both tissue harmonic imaging and volume contrast imaging with a 15 mm thickness ( P<0.001) and was judged to be marginally better than with a 10 mm thickness ( p>0.01). With regard to acoustic shadowing, volume contrast imaging with thin slice thicknesses was also significantly better than with thick slice thicknesses ( P<0.01), and it was also marginally better than tissue harmonic imaging ( P>0.01). Volume contrast US imaging with thin slice thicknesses provides a better image quality with fewer artifacts than three other types of images for the evaluation of gallbladder diseases.