Use of accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography to evaluate tumor vessels in focal nodular hyperplasia and other hepatic tumors

Purpose To evaluate the usefulness of accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography for examining tumor vessels in focal nodular hyperplasia and other hepatic lesions. Methods After injecting a galactose-palmitic acid contrast agent, we used conventional contrast-enhanced harmonic grayscale ultrasonography to scan 8 focal nodular hyperplasia lesions, 21 hepatocellular carcinomas, 2 cholangiocellular carcinomas, 12 hepatic metastases, 17 hemangiomas, and 2 angiomyolipomas. We then accumulated and superimposed consecutive conventional images (accumulation images) and compared them with corresponding conventional images to evaluate serial images of hepatic tumor vessels. Results Serial tumor vessel findings obtained from accumulation images were superior to those obtained from conventional images in 51 (77%) of the 66 various hepatic lesions examined. Evidence of the spoke-wheel artery pattern in 2 of the 8 focal nodular hyperplasia lesions was equivocal in the conventional images, but accumulation images clearly depicted serial images of spoke-wheel arteries, clearly indicating a diagnosis of focal nodular hyperplasia. Accumulation images allowed the diagnosis of two additional focal nodular hyperplasia lesions that had not been correctly diagnosed as focal nodular hyperplasia from conventional images. Conclusion Accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography are useful in evaluating hepatic tumor vessels, especially spoke-wheel arteries, which specifically indicate focal nodular hyperplasia.