Focal Hepatic Lesions: Evaluation with Contrast-Enhanced Gray-Scale Harmonic US

Abstract

ObjectiveTo determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization.Materials and MethodsThe study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed.ResultsAt vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase.ConclusionAt contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.

Detection of hepatocellular carcinoma capsule by contrast-enhanced ultrasound using Levovist: correlations with pathological findings

“…2 The CEUS appearance of HCC in the vascular or late phase has also been described for ADI 3,4 and other methods. [5][6][7] However, no report to date has described the differences between encapsulated and nonencapsulated HCC. Tanaka et al 8 reported that most HCC nodules in which a reticular enhancement pattern was observed in the parenchymal phase had a fibrous capsule or septa in a configuration similar to that of reticular enhancement.…”

Evaluation of Hepatic Focal Nodular Hyperplasia With Contrast-Enhanced Gray Scale Harmonic Sonography

“…Among various gray scale harmonic imaging techniques recently developed to overcome the shortcomings of conventional harmonic imaging, CHA is the one that separates harmonic signals from tissue and those from contrast agents and boosts harmonic return from the latter, which suppresses not only fundamental but also harmonic signals from the background tissue. [14][15][16] Thus, CHA is specifically sensitive to signals from a contrast agent but without contrast-related artifacts. The resultant high sensitivity to a contrast agent provides a sufficient stimulated acoustic emission effect at a medium MI, whereas other gray scale harmonic techniques usually require a maximal MI to achieve that.…”

“…The resultant high sensitivity to a contrast agent provides a sufficient stimulated acoustic emission effect at a medium MI, whereas other gray scale harmonic techniques usually require a maximal MI to achieve that. 12,16,27 Furthermore, because there is less destruction of microbubbles, a period of continuous scanning is possible. We performed all contrast-enhanced sonographic examinations with a combination of a short period of continuous scanning and intermittent acoustic emission imaging at the same medium MI (0.6-0.8).…”

“…In addition to this, most HCCs showed a hypoechoic feature compared with the surrounding liver during the delay phase of acoustic emission imaging because most HCCs usually do not have normal hepatic sinusoids and Kupffer cells. 16,27 These 2 points appear helpful for differentiating FNH from adenomas or HCCs.…”

“…It has been recently reported that CHA in conjunction with a scan technique exploiting both vascular and acoustic emission imaging accurately represented the vascular and dynamic enhancement patterns of various focal liver lesions. 16 The purpose of this study was to assess the potential of contrast-enhanced gray scale harmonic sonography using a CHA technique in the evaluation of typical vascular and enhancement patterns of hepatic FNH.…”