Tissue harmonic imaging sonography: evaluation of image quality compared with conventional sonography

The purpose of this study was to determine if tissue harmonic imaging (THI) sonography produced higher quality images than did conventional sonography. A prospective study was performed on 89 patients to compare the image quality of THI sonography with that of conventional sonography. Each examination was performed using THI sonography (transmitted frequency, 2.0 MHz; received frequency, 4.0 MHz) and conventional sonography at 2.5 and 4.0 MHz. The pancreatic area was studied in 60 patients, and other anatomic areas were studied in 68 patients. The images were then graded for penetration, detail, and total image quality. Graders were unaware of the sonographic technique. Of the 60 pancreatic examinations, THI sonography was the best technique for penetration in 45, detail in 54, and total image quality in 50. For the pancreas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .0002), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001). Of the 68 examinations of other anatomic areas, THI sonography was the best technique for penetration in 42, detail in 57, and total image quality in 58. For other anatomic areas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .05), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001). The THI technique improved sonographic image quality.