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Focal hepatic lesions: evaluation with contrast-enhanced dynamic gray-scale harmonic US imaging
Abstracts excellent method in evaluating typical vascular and enhancement pattern of hepatic focal nodular hyperplasia. 31980 Early assessment of therapeutic response to radiofrequency ablation in hepatocellular carcinoma: Utility of gray scale harmonic ultrasound with a microbubble contrast agent Lim HK, Jang KM,* Kim M, Choi D, Lee WJ, Kim SH, Lim JH, Department of Radiology, Samsung Medical Center, Syunkyunkwan University School of Medicine, Seoul, South Korea Objective: The aim of this study was to evaluate the utility of gray scale harmonic ultrasound with a microbubble contrast agent in the early assessment of therapeutic response to radiofrequency (RF) ablation in hepatocellular carcinoma (HCC). Methods: Forty-one patients with 45 nodular HCCs (1.4 – 4.8 cm; mean⫽2.8 cm) treated with percutaneous RF ablation were evaluated with contrast-enhanced gray scale harmonic US imaging (Coded Harmonic Angio, GE Medical Systems, Milwaukee, WI, U.S.A.) following intravenous volus injection of a microbubble contrast agent. The vascularity within the ablated lesions was evaluated with a continuous scan between 15–30 seconds after initiation of contrast injection. To evaluate the perfusion of the ablated lesions, intermittent acoustic emission imaging was performed with a rapid sweeping technique from the end of the continuous scan to 90 seconds after initiation of contrast injection. The results were compared with follow-up three-phase helical CT in terms of the presence or absence of residual viable tumor. Results: In seven (15.6%) of the 45 treated HCCs, contrast-enhanced US examinations showed nodular or crescentic enhancing foci (0.8 –1.7 cm in greatest dimension) at the margin of the treated lesions, representing the residual viable tumor. In the remaining 38 HCCs (84.4%), contrast-enhanced US examinations showed no evidence of enhancing foci, suggesting successful treatment. Contrast-enhanced CT obtained 1 month after RF ablation confirmed the residual viable tumor in the same seven lesions. The diagnostic agreement between 1-month follow-up CT and contrast-enhanced US examinations was achieved in 100%. The remaining 38 ablated lesions with the absence of residual viable tumor at CT and contrast-enhanced US were followed up for at least 12 months (range 12–27 months, mean 18 months). Subsequent follow-up CT showed local recurrence at the margins of 2 lesions (5.3%). Conclusions: Contrast-enhanced gray scale harmonic ultrasound imaging can be a reliable alternative to contrast-enhanced CT in the early assessment of therapeutic response to RF ablation in HCC, as it showed comparable high diagnostic accuracy compared with CT.
31982 Focal hepatic lesions: Evaluation with contrast-enhanced dynamic gray-scale harmonic US imaging Lim HK,* Jang H, Kim M, Lee WJ, Jang KM, Lim JH, Choi D, Department of Radiology, Samsung Medical Center, Syunkyunkwan University School of Medicine, Seoul, South Korea Objective: The aim of this study was to describe the findings of various focal hepatic lesions on contrast-enhanced gray-scale harmonic ultrasound (US) imaging with an emphasis on lesion characterization. Methods: The study included 101 patients with 111 focal hepatic lesions consisting of 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, 10 focal nodular hyperplasias (FNHs), and six
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nontumorous nodules. After injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed, combined with continuous scan during arterial phase to assess intratumoral vasculature (vascular imaging) and intermittent acoustic emission imaging during arterial, portal, and equilibrium phases for sequential enhancement pattern. Each imaging pattern was categorized and analyzed. Results: On vascular imaging, 69% of HCCs showed irregular branching vessels (35/51), and 91% of metastasis (20/22) showed peripherally stippled pattern. All of the hemangiomas showed peripheral fine vascularities. 90% of FNHs (9/10) showed a central artery of spoke-wheel pattern. On emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement, and 86% (19/22) of metastasis showed rim- or flame-like peripheral enhancement during early phase. With all HCCs and metastasis (100%, 73/73) being washed out during late phase, hemangiomas showed either peripheral nodular (19/22, 86%) or persistent homogeneous enhancement (3/22, 14%), and 75% of FNHs (3/4) became either hyprechoic or isoechoic during portal and equilibrium phases. Conclusions: Contrast-enhanced gray-scale harmonic US imaging using a CHA technique enabled some period of continuous scan to depict intratumoral vasculature as well as intermittent acoustic emission imaging and thus provided characteristic findings of various focal hepatic lesions.
31983 Rabbit eye perfusion analysis with ultrasound agent infusion at low mechanical index Hirokawa T,* Kajima M, Naito T, Shiota H, Department of Ophthalmology and Visual Neurosciences, The University of Tokushima, Tokushima, Japan Objective: Nowadays a link between eye disease and eye perfusion receives much attention. However, orbital ultrasound examinations are not in general use because ultrasound output is especially strictly stipulated at orbital ultrasound examinations. The purpose of this experiment is to verify whether difference of perfusion between orbital tissues can be examined quantitatively at low MI with ultrasound contrast agent. Methods: Five rabbits were employed. The contrast agent perflutren was administrated constantly via rabbits’ ear vein at a 10 microL/min. Ultrasonography was performed by phase inversion imaging. After the tissues’ video intensity had leveled off, pulsing interval was suddenly altered from 1 Hz to 12 Hz, and the change of orbital tissues’ video intensity was observed. Mechanical index was always under 0.2. If every pulse destroys the same number of agents in the tissues within a frame, their video intensity should be gradually decreased frame by frame because the agent destroyed rate exceeds the agent supply rate by perfusion. We know that the video intensity versus pulsing interval plots were fitted to a function: y ⫽ Ae*⫺t ⫹C, where A is the plateau video intensity, beta reflects the rate of rise of video intensity, and C is constant (Takagi et al). Results: Known high-perfusion tissue, uvea, shows high value of beta and A, and to the contrary, known low-perfusion tissue shows optic nerve low value. Conclusions: Our findings suggested that the difference between orbital tissues’ perfusion can be detected quantitatively within regulation.
31982 Focal hepatic lesions: Evaluation with contrast-enhanced dynamic gray-scale harmonic US imaging Lim HK,* Jang H, Kim M, Lee WJ, Jang KM, Lim JH, Choi D, Department of Radiology, Samsung Medical Center, Syunkyunkwan University School of Medicine, Seoul, South Korea Objective: The aim of this study was to describe the findings of various focal hepatic lesions on contrast-enhanced gray-scale harmonic ultrasound (US) imaging with an emphasis on lesion characterization. Methods: The study included 101 patients with 111 focal hepatic lesions consisting of 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, 10 focal nodular hyperplasias (FNHs), and six
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nontumorous nodules. After injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed, combined with continuous scan during arterial phase to assess intratumoral vasculature (vascular imaging) and intermittent acoustic emission imaging during arterial, portal, and equilibrium phases for sequential enhancement pattern. Each imaging pattern was categorized and analyzed. Results: On vascular imaging, 69% of HCCs showed irregular branching vessels (35/51), and 91% of metastasis (20/22) showed peripherally stippled pattern. All of the hemangiomas showed peripheral fine vascularities. 90% of FNHs (9/10) showed a central artery of spoke-wheel pattern. On emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement, and 86% (19/22) of metastasis showed rim- or flame-like peripheral enhancement during early phase. With all HCCs and metastasis (100%, 73/73) being washed out during late phase, hemangiomas showed either peripheral nodular (19/22, 86%) or persistent homogeneous enhancement (3/22, 14%), and 75% of FNHs (3/4) became either hyprechoic or isoechoic during portal and equilibrium phases. Conclusions: Contrast-enhanced gray-scale harmonic US imaging using a CHA technique enabled some period of continuous scan to depict intratumoral vasculature as well as intermittent acoustic emission imaging and thus provided characteristic findings of various focal hepatic lesions.
31983 Rabbit eye perfusion analysis with ultrasound agent infusion at low mechanical index Hirokawa T,* Kajima M, Naito T, Shiota H, Department of Ophthalmology and Visual Neurosciences, The University of Tokushima, Tokushima, Japan Objective: Nowadays a link between eye disease and eye perfusion receives much attention. However, orbital ultrasound examinations are not in general use because ultrasound output is especially strictly stipulated at orbital ultrasound examinations. The purpose of this experiment is to verify whether difference of perfusion between orbital tissues can be examined quantitatively at low MI with ultrasound contrast agent. Methods: Five rabbits were employed. The contrast agent perflutren was administrated constantly via rabbits’ ear vein at a 10 microL/min. Ultrasonography was performed by phase inversion imaging. After the tissues’ video intensity had leveled off, pulsing interval was suddenly altered from 1 Hz to 12 Hz, and the change of orbital tissues’ video intensity was observed. Mechanical index was always under 0.2. If every pulse destroys the same number of agents in the tissues within a frame, their video intensity should be gradually decreased frame by frame because the agent destroyed rate exceeds the agent supply rate by perfusion. We know that the video intensity versus pulsing interval plots were fitted to a function: y ⫽ Ae*⫺t ⫹C, where A is the plateau video intensity, beta reflects the rate of rise of video intensity, and C is constant (Takagi et al). Results: Known high-perfusion tissue, uvea, shows high value of beta and A, and to the contrary, known low-perfusion tissue shows optic nerve low value. Conclusions: Our findings suggested that the difference between orbital tissues’ perfusion can be detected quantitatively within regulation.