Publications (18)29.96 Total impact
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Article: Real-Time Ultrasound Attenuation Imaging of Diffuse Fatty Liver Disease.
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ABSTRACT: A method for real-time ultrasound attenuation imaging and quantification is proposed in this paper. We employed a simple algorithm for comparing two signal intensities of different frequencies to extract attenuation quantitatively. The usefulness of this method was verified by numerical simulation of the acoustic field and validated by phantom experiments. The accuracy of the results was reduced by noise in areas with a low signal-to-noise ratio, but we found that the effects of noise could be reduced by applying our noise cancellation technique or simply setting a sufficiently high gain. The estimated attenuation coefficients for clinical liver images showed acceptable correlation with the liver-to-spleen ratio of computed tomography numbers. These findings suggest that real-time attenuation parametric imaging may be able to replace CT for quantifying the degree of fatty infiltration of the liver. However, further development is needed to obtain the local attenuation distribution in cross sections with sufficient reliability.Ultrasound in medicine & biology 02/2013; · 2.02 Impact Factor -
Article: Hepatocellular carcinoma treated with sorafenib: early detection of treatment response and major adverse events by contrast-enhanced US.
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ABSTRACT: BACKGROUND/AIMS: Early prediction of tumour response and major adverse events (AEs), especially liver failure, in patients with hepatocellular carcinoma (HCC) is essential for maximizing the clinical benefits of sorafenib. To evaluate the usefulness of dynamic contrast-enhanced ultrasound (DCE-US) for the early prediction of tumour response and major AEs in HCC patients. METHODS: Thirty-seven HCC patients were started on a reduced dosage of sorafenib, subsequently increased to the standard dosage. Tumour response at 1 month was assessed by CT using the Response Evaluation Criteria in Solid Tumors (RECIST). Major AEs were defined as grade 3 or higher. DCE-US was performed before treatment (day 0) and on days 7, 14 and 28. Changes in perfusion parameters in the tumour and liver parenchyma between day 0 and later time points were compared between treatment responders and nonresponders based on RECIST and between patients who experienced major AEs and those who did not. Tumour results were also compared with progression-free survival (PFS) and overall survival (OS). RESULTS: Tumour perfusion parameters based on the area under the time-intensity curve (AUC) were statistically significant, with AUC during washin on day 14, the most relevant for tumour response (P = 0.0016) and AUC during washin on day 7, the most relevant for both PFS (P = 0.009) and OS (P = 0.037). A decrease in total AUC between days 0 and 7 in the liver parenchyma was strongly correlated with major AEs (P = 0.0002). CONCLUSION: DCE-US may be useful for the early prediction of tumour response and major AEs in patients with HCC.Liver international: official journal of the International Association for the Study of the Liver 01/2013; · 3.82 Impact Factor -
Article: Quantification in molecular ultrasound imaging: a comparative study in mice between healthy liver and a human hepatocellular carcinoma xenograft.
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ABSTRACT: Objectives The purpose of this study was to quantitatively assess the contrast kinetics of vascular endothelial growth factor receptor 2 (VEGFR2)-targeted microbubbles (BR55; Bracco Suisse, Geneva, Switzerland) compared to clinically used microbubbles (SonoVue; Bracco SpA, Milan, Italy) in both normal liver and human hepatocellular carcinoma xenograft tumors in mice. Methods Microbubbles were injected intravenously into healthy mice (n = 5) and mice bearing hepatocellular carcinoma xenograft tumors (n = 10). Cine loops of contrast enhancement in normal liver and the tumors were acquired for 10 minutes. Quantitative perfusion parameters were derived by fitting time-intensity curves using a dedicated mathematical model combining a bolus function and a ramp function. Immunohistochemical examinations were also performed for normal liver and tumor specimens to determine the level of VEGFR2 expression. Results The peak contrast enhancement observed in normal liver with BR55 was comparable to that with SonoVue, whereas a significant difference was observed in latephase enhancement at 10 minutes (ramp slope: P < .01). In the tumor model, SonoVue was rapidly cleared from the circulation, without any noticeable binding in the tumor, whereas BR55 showed a gradual decline, resulting in a longer wash-out period (mean transit time: P < .01). Immunohistochemical examinations showed that intratumoral vascular endothelial cells had sparse and weak VEGFR2 expression, whereas the sinusoidal capillaries in normal liver had much more diffuse and much stronger expression. Conclusions Our results suggest that BR55 accurately reflects the VEGFR2 status in human hepatocellular carcinoma xenograft tumors. We showed that quantification applied to molecular ultrasound imaging may provide an objective method for measuring the degree of microbubble binding.Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 12/2012; 31(12):1909-16. · 1.25 Impact Factor -
Article: Parametric imaging using contrast-enhanced ultrasound with Sonazoid for hepatocellular carcinoma
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ABSTRACT: PurposeTo clarify the usefulness of parametric imaging using contrast-enhanced ultrasound (CE-US) with Sonazoid by comparing parametric images of hepatocellular carcinoma (HCC) with histopathological findings. MethodsTwo patients with HCCs underwent CE-US with Sonazoid before surgical resection. A single focus point was set at the lower margin of the tumor, and a bolus intravenous injection of Sonazoid (0.5ml) was administered. Images of the ideal scanning plane were displayed in real-time mode for the early vascular phase. We analyzed these images using prototype PC software. The software watches, pixel by pixel, the increase in the intensity due to the inflow of the microbubbles, and displays colors if the intensity becomes larger than a certain threshold. Parametric images were compared with histopathological findings. ResultsThe level of blood flow in the tumor could be visually evaluated using a single image by expressing the detailed hemodynamics of the tumor in terms of differences in color using a time axis appropriate for each case. ConclusionsParametric imaging is a very useful way of facilitating straightforward visualization of the level of blood flow within HCC and the distribution of histopathological findings in single static images. KeywordsContrast-enhanced ultrasound-Sonazoid-Parametric image-Time-intensity curve-Hepatocellular carcinomaJournal of Medical Ultrasonics 04/2012; 37(2):81-86. · 0.33 Impact Factor -
Article: A case of high-flow hepatic hemangioma: analysis by parametoric imaging using sonazoid-enhanced ultrasonography
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ABSTRACT: KeywordsHepatic hemangioma-Contrast-enhanced ultrasonography-Sonazoid-Parametoric imagingJournal of Medical Ultrasonics 04/2012; 37(2):87-90. · 0.33 Impact Factor -
Article: Comparison of ultrasound colored image views produced by application of statistical analysis of radio-frequency signals and histological findings in patients with chronic hepatitis C
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ABSTRACT: PurposeTo assess the tissue characteristics of chronic liver disease, we statistically analyzed the speckle signal from liver parenchyma. Subjects and methodsAnalysis was performed for 65 patients with biopsy-proven chronic hepatitis C; individuals with fatty liver, heavy drinkers, and those with a thick abdominal wall were excluded. The probability density function of radio-frequency signal amplitude was statistically analyzed using a new analytical method. We focused on strong signals which deviated remarkably from the Rayleigh distribution. By applying the analytical results, lesions that caused the strong signals were displayed as red scatter overlaid on B-mode images (we called the red scatter “US-Red” in this study). US-Red% occupancy on the color image was statistically compared with pathological findings. ResultsUS-Red suggests the existence of an acoustic reflectional plane mainly formed of fibrous bridge and septa. US-Red% increased significantly with progression of liver fibrosis stage. US-Red% varied widely in cirrhosis, and US-Red% in the large nodule group was significantly higher than that in the small nodule group. ConclusionThe results suggest that US-Red% is useful for evaluating liver fibrosis stage (F1–3) and the size of nodules in cirrhosis. In addition, visually detecting the acoustic reflectional plane, which increases with progression of disease, as color images will be clinically beneficial. KeywordsTissue characterization-Speckle-Acoustic reflectional plane-Probability density function-Rayleigh distributionJournal of Medical Ultrasonics 04/2012; 37(2):51-58. · 0.33 Impact Factor -
Article: Usefulness of arrival time parametric imaging in evaluating the degree of liver disease progression in chronic hepatitis C infection.
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ABSTRACT: To determine whether the degree of liver disease progression in chronic hepatitis C infection can be evaluated by arrival time parametric imaging using contrast-enhanced sonography with Sonazoid (perfluorobutane; GE Healthcare, Oslo, Norway). In this study, 60 patients with liver disease in chronic hepatitis C infection were examined and compared with 10 healthy volunteers who served as controls. A recommended dose of the sonographic contrast agent Sonazoid was intravenously infused, and the S5 or S6 region of the liver and right kidney were observed concurrently while movies of the procedure were saved. Arrival time parametric images of liver parenchymal blood flow were created, with red pixels to indicate an arrival time of 0 to 5 seconds and yellow pixels to indicate an arrival time of 5 to 10 seconds. From the obtained images, the ratio of the red area to the entire enhanced area of the liver was calculated using image-processing software. Each participant was subsequently subjected to liver biopsy for liver fibrosis staging according to Metavir scores, and the determined fibrosis stage was compared with the ratio of red. The serum albumin level, platelet count, and prothrombin time were also compared with the ratio of red for each participant. The ratio of red increased significantly as liver fibrosis stage advanced (P < .01 for F1 versus F2; P < .01 for F1 versus F3; P < .01 for F1 versus F4; and P < .01 for F2 versus F4). As the ratio of red increased, significant decreases were observed in the serum albumin level (r = -0.29; P = .027), platelet count (r = -0.46; P = .0003), and prothrombin time (r = -0.46; P = .0002). Arrival time parametric imaging using Sonazoid-enhanced sonography enables noninvasive evaluation of the degree of progression of liver disease in chronic hepatitis C infection and is thus considered clinically useful.Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 03/2012; 31(3):373-82. · 1.25 Impact Factor -
Article: Diagnosis of hepatic hemangioma by parametric imaging using sonazoid-enhanced US.
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ABSTRACT: Comparison of Parametric Imaging (PI) using Sonazoid-enhanced ultrasonography (US) and microflow imaging (MFI) to determine the possibility of hepatic hemangioma diagnosis using PI. Twenty-two hepatic hemangioma nodules (mean±SD diameter: 31.6±19.1mm) undergoing Sonazoid-enhanced US between February 2008 and March 2009. After Sonazoid-enhanced US, COMMUNE ultrasonographic image analysis software was used for analysis of tumor imaging dynamics in the vascular phase using PI and MFI. In PI, 0s was set as the time contrast agent reached the tumor. Imaging within the tumor after 0s was color-coded according to time, and the images were displayed in color. In MFI, 0s was set as the time contrast agent reached the tumor. The path of microbubbles as it flowed through blood vessels was superimposed on the original B-mode images. Three trained physicians used these methods to analyze tumor imaging dynamics. All physicians concluded all cases were hepatic hemangioma regardless of method used. However, compared to MFI, PI allowed determination of more detailed blood flow dynamics in high-flow hepatic hemangioma, where blood flow speed was faster than in normal hepatic hemangioma. It is possible to diagnose hepatic hemangioma using PI using sonazoid-enhanced US.Hepato-gastroenterology 07/2011; 58(110-111):1431-5. · 0.66 Impact Factor -
Article: Drinking status of heavy drinkers detected by arrival time parametric imaging using sonazoid-enhanced ultrasonography: study of two cases.
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ABSTRACT: Chronic heavy consumption of alcohol is associated with increased risks of developing liver cirrhosis, hepatocellular carcinoma, and esophageal varices. Cessation of alcohol consumption is the most important requirement in treating these diseases. However, judging whether patients have actually maintained abstinence from alcohol requires reliance on their reports, which vary substantially across individuals using the test methods currently available. Arrival time parametric imaging (At-PI) using Sonazoid-enhanced ultrasonography is regarded as a useful approach for assessing the progression of lesions that have developed in liver parenchyma. In this study, we report two cases for whom this approach was successfully applied to indicate the drinking status of a heavy drinker. At-PI enables approximate and objective assessment of the drinking status of patients, independent of their reports; therefore, it is a promising method for providing information about drinking status.Case Reports in Gastroenterology 01/2011; 5(1):100-9. -
Article: Computer-aided diagnosis for the classification of focal liver lesions by use of contrast-enhanced ultrasonography.
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ABSTRACT: The authors developed a computer-aided diagnostic (CAD) scheme for classifying focal liver lesions (FLLs) as liver metastasis, hemangioma, and three histologic differentiation types of hepatocellular carcinoma (HCC), by use of microflow imaging (MFI) of contrast-enhanced ultrasonography. One hundred and three FLLs obtained from 97 cases used in this study consisted of 26 metastases (15 hyper- and 11 hypovascularity types), 16 hemangiomas (five hyper- and 11 hypovascularity types) and 61 HCCs: 24 well differentiated (w-HCC), 28 moderately differentiated (m-HCC), and nine poorly differentiated (p-HCC). Pathologies of all cases were determined based on biopsy or surgical specimens. Locations and contours of FLLs on contrast-enhanced images were determined manually by an experienced physician. MFI was obtained with contrast-enhanced low-mechanical-index (MI) pulse subtraction imaging at a fixed plane which included a distinctive cross section of the FLL. In MFI, the inflow high signals in the plane, which were due to the vascular patterns and the contrast agent, were accumulated following flash scanning with a high-MI ultrasound exposure. In the initial step of our computerized scheme, a series of the MFI images was extracted from the original cine clip (AVI format). We applied a smoothing filter and time-sequential running average techniques in order to reduce signal noise on the single MFI image and cyclic noise on the sequential MFI images, respectively. A kidney, vessels, and a liver parenchyma region were segmented automatically by use of the last image of a series of MFI images. The authors estimated time-intensity curves for an FLL by use of a series of the temporally averaged MFI images in order to determine temporal features such as estimated replenishment times at early and delayed phases, flow rates, and peak times. In addition, they extracted morphologic and gray-level image features which were determined based on the physicians' knowledge of the diagnosis of the FLL, such as the size of lesion, vascular patterns, and the presence of hypoechoic regions. They employed a cascade of six independent artificial neural networks (ANNs) by use of extracted temporal and image features for classifying five types of liver diseases. A total of 16 temporal and image features, which were selected from 43 initially extracted features, were used for six different ANNs for making decisions at each decision in the cascade. The ANNs were trained and tested with a leave-one-lesion-out test method. The classification accuracies for the 103 FLLs were 88.5% for metastasis, 93.8% for hemangioma, and 86.9% for all HCCs. In addition, the classification accuracies for histologic differentiation types of HCCs were 79.2% for w-HCC, 50.0% for m-HCC, and 77.8% for p-HCC. The CAD scheme for classifying FLLs by use of the MFI on contrast-enhanced ultrasonography has the potential to improve the diagnostic accuracy in the histologic diagnosis of HCCs and the other liver diseases.Medical Physics 06/2008; 35(5):1734-46. · 2.83 Impact Factor -
Article: Analysis of morphological vascular changes of hepatocellular carcinoma by microflow imaging using contrast-enhanced sonography.
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ABSTRACT: Aim: To determine whether the findings of microflow imaging (MFI), composed of a flash replenishment and a maximum intensity holding sequence, using contrast-enhanced sonography, correlate with the degree of histological differentiation of hepatocellular carcinoma (HCC). Methods: This study was approved by the institutional review board; patients gave informed consent. The samples comprised of 61 nodules histologically diagnosed as HCC: 20 well-differentiated, 26 moderately-differentiated, and 15 poorly-differentiated HCC. SonoVue was used as the ultrasound (US) contrast agent. The US equipment used was a SSA-770 A with the imaging mode set at MFI. MFI is an imaging method combining flash replenishment imaging and maximum intensity holding. Two independent readers (readers 1 and 2) classified the microflow images into four patterns: (i) normal pattern; (ii) cotton pattern; (iii) vascular pattern; and (iv) dead wood pattern. The results were compared with the degree of histopathological differentiation of the HCC. Results: In each of the 61 HCC, blood vessels in the tumor were clearly resolved down to their fine branches. With regard to the relationship between imaging patterns and thehistological findings, it was found (with high percentages) that the normal and cotton patterns were associated with well-differentiated HCC, that the vascular pattern was associated with moderately-differentiated HCC, and that the dead wood pattern was associated with poorly-differentiated HCC. If HCC with the normal and cotton patterns were assessed as well differentiated and those with the vascular or dead wood pattern were assessed as moderately or poorly differentiated, the sensitivity, specificity, and accuracy of these assessments were found to be 85%, 92.7%, and 90%, respectively, for reader 1, and 85%, 82.9%, and 83.6%, respectively, for reader 2. Conclusion: The angioarchitecture and hemodynamics of HCC could be evaluated in detail using MFI. The results of this study demonstrate the feasibility of a non-invasive preoperative diagnosis of the histological differentiation of HCC using MFI.Hepatology Research 06/2008; 38(8):790-9. · 2.20 Impact Factor -
Article: Real-time temporal maximum-intensity-projection imaging of hepatic lesions with contrast-enhanced sonography.
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ABSTRACT: OBJECTIVE: We sought to perform a preliminary evaluation of temporal maximum intensity projection (MIP) of focal hepatic masses in selected patients. The technique processes real-time contrast-enhanced sonography images by integrating the path of moving bubbles to depict vascular morphology. Following a high-intensity ultrasound pulse that disrupts bubbles within the scan plane, MIP images the trajectories of fresh bubbles replenishing the plane and revealing their course. CONCLUSION: Vascular morphology is depicted at a level or detail not seen before with sonography. High-frame-rate sequences of less than one second uniquely show arterial structure in liver lesions.American Journal of Roentgenology 04/2008; 190(3):691-5. · 2.78 Impact Factor -
Article: Medical Imaging
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ABSTRACT: We have developed a computer-aided diagnostic (CAD) scheme for classifying focal liver lesions (FLLs) into hepatocellular carcinoma (HCC), liver metastasis, and hemangioma, by use of B-mode and micro flow imaging (MFI) of contrast-enhanced ultrasonography. We used 98 cases in this study, in which 104 FLLs consisted of 68 HCCs, 21 metastases, and 15 hemangiomas. MFI was obtained with contrast-enhanced low-mechanical-index (MI) pulse subtraction imaging at a fixed plane which included a distinctive cross section of the FLL. In the MFI, the inflow high signals in the plane, which were due to the vascular patterns and the contrast agent, were accumulated following flash scanning with a high-MI ultrasound exposure. In this study, in addition to the existing 29 image features extracted from MFI images, such as replenishment time, the average and the standard deviation of pixel values in a FLL, and the average thickness of vessel-like patterns, four types of image features were extracted from MFI, temporal subtraction and B-mode images based on small square regions of interest (ROIs: 4x4 matrix size) placed to cover a whole region of the FLL. The four features were 1) uniformity of average pixel values for all ROIs, 2) peak pixel values in a histogram of average pixel values of ROIs, 3) fraction of hypoechoic regions within an FLL, and 4) cross-correlation of pixel values within an FLL between B-mode and MFI images. Overall classification accuracies performed by this CAD scheme were 87.5% for all 104 liver lesions.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.03/2008; -
Article: Correlation between parametric imaging using contrast ultrasound and the histological differentiation of hepatocellular carcinoma.
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ABSTRACT: Aim: To determine whether parametric imaging correlates with the degree of histological differentiation of hepatocellular carcinoma (HCC). Methods: The samples comprised 49 nodules diagnosed histologically as HCC: 19 well differentiated (w-HCC), 22 moderately differentiated (m-HCC), and eight poorly differentiated (p-HCC). The ultrasound (US) equipment used was SSA-770 A (Toshiba Medical Systems, Otawara, Japan) and the contrast agent was SonoVue (Bracco, Milan, Italy). After 1.5 mL of SonoVue was injected intravenously and staining of the tumors and parenchyma was confirmed, microbubbles in the scanned volume were eliminated using high mechanical index (MI) scanning frames. The "arrival time (T(A)) images," reflecting beta-values, were displayed with color codes at the phase after reperfusion. Images at the phase when the staining reached a plateau (90-180 s) were used as "A images," reflecting A values. These images were compared between each histological grade of differentiation. Results: Analysis of T(A) images indicated that beta-values in m-HCC were higher than those in the adjacent non-tumor parenchyma in all 22 samples and also were significantly higher than in the other HCCs (P < 0.001 for w-HCC; P < 0.05 for p-HCC). Furthermore, beta-values in p-HCC samples had significantly larger variations in terms of time and space than in the other HCCs (P < 0.001 for w-HCC; P < 0.01 for m-HCC). Analysis of A images indicated that the A value for w-HCC was significantly higher than those for either m-HCC or p-HCC (P < 0.001). Conclusion: Both T(A) and A images were useful for diagnosing the histological differentiation of HCC.Hepatology Research 03/2008; 38(3):273-80. · 2.20 Impact Factor -
Article: How to characterize non-hypervascular hepatic nodules on contrast-enhanced computed tomography in chronic liver disease: feasibility of contrast-enhanced ultrasound with a microbubble contrast agent.
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ABSTRACT: Although hypervascular appearance is characteristic in hepatocellular carcinoma (HCC), hepatic nodules without hypervascular appearance are sometimes found in patients with chronic liver disease (CLD). The aim of the present study was to clarify the efficacy of contrast-enhanced ultrasound (CEUS) with Levovist to characterize small, non-hypervascular hepatic nodules on contrast-enhanced computed tomography (CECT) in patients with CLD. The subject was 41 hepatic nodules (<30 mm, 18.5 +/- 5.6 mm) which showed non-hypervascular appearance on CECT in 35 patients with CLD; their histological results were 31 HCC (15 well, 14 moderate, and two poor) and 10 regenerative nodules (RN). CEUS with Levovist was performed under intermittent scanning (1-s interval) using APLIO at the early phase and the liver-specific phase, and the contrast enhancement of the nodule was assessed in comparison to that of the surrounding liver parenchyma. The contrast-enhanced findings with the time-intensity analysis were compared with the histological results. Twelve nodules with weak enhancement in the liver-specific phase were HCC, regardless of their early-phase appearances. The other 29 nodules with equivalent or weak enhancement in the early phase and equivalent enhancement in the liver-specific phase were 19 HCC and 10 RN. Among them, the maximum-intensity ratio of tumor to non-tumor in the early phase was significantly higher in HCC than in RN (P < 0.01, n = 16), and the receiver-operating characteristic analysis showed a sensitivity of 1.0 and a specificity of 0.83 for their characterization. CEUS with Levovist may be an alternative to biopsy to characterize small, non-hypervascular hepatic nodules on CECT in patients with CLD.Journal of Gastroenterology and Hepatology 10/2007; 23(10):1528-34. · 2.87 Impact Factor -
Article: Parametric imaging of contrast ultrasound for the evaluation of neovascularization in liver tumors.
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ABSTRACT: Aim: To assess the efficacy of parametric imaging for the diagnosis of neovascularization in liver tumors. Methods: The subjects were 17 rabbits (five with normal liver and 12 with VX2 tumor implanted in the liver). The contrast agents used were SonoVue (Bracco, Milan, Italy). A diagnostic ultrasound system was used with a programmable replenishment sequence. The images obtained between the initial frame after the high mechanical index (MI) scan, which diminishes microbubbles in the scan volume, and the current frame were coded in color according to the arrival and peak times. After the experiment, the tumors were excised and sectioned. Sections were prepared for light microscopy with hematoxylin-eosin (HE) staining and CD31 staining to evaluate vascular density. Results: Arrival time imaging (ATI) delineated the fine blood vessels (100-200 mum in diameter) in all of the rabbits. Tortuous and meandering tumor vessels were visualized in the VX2 tumors. Differences of perfusion velocity between tumor tissue and tumor-free areas were shown in peak time imaging (PTI). Vascularity evaluated on the ATI and perfusion speed recognized on the ATI and PTI were related to the vascular density measured by pathological investigation. Conclusion: Parametric imaging is a promising new method for the visualization of perfusion and the estimation of tumor blood vessels.Hepatology Research 07/2007; 37(6):464-72. · 2.20 Impact Factor -
Article: Quantification of hepatic parenchymal blood flow by contrast ultrasonography with flash-replenishment imaging.
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ABSTRACT: Flash-replenishment (FR) utilizes destruction of microbubbles in the scan volume by high-power ultrasound and enables to observe reperfusion at a low acoustic power. In this paper, we introduced theoretic equation between probability density function (PDF) of the transit time in the scan volume and time intensity curve (TIC) measured by FR method. From the equations, it was explained that the mean transit time (MTT) through the scan volume was calculated from the plateau level and tangent of the initial slope. Animal experiments were also performed to measure TIC in the parenchymal region of the liver using FR method. From the result of the TIC, the variant of the PDF for the transit time was found to be small and the average MTT was 11.1 s. Hepatic blood flow by an ultrasonic transit time flowmeter was also measured in the same experiment, and adequate correlation was obtained from between the two methods. The results suggested that the FR method, which is a noninvasive measurement, can predict the blood flow of the liver.Ultrasound in Medicine & Biology 11/2006; 32(10):1459-66. · 2.29 Impact Factor -
Article: Sonographic shift of hypervascular liver tumor on blood pool harmonic images with definity: time-related changes of contrast-enhanced appearance in rabbit VX2 tumor under extra-low acoustic power.
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ABSTRACT: We elucidated the features of the time-related contrast-enhanced ultrasound appearance of hypervascular liver tumor using Definity, which has no accumulation activity in the liver. Ten rabbits with VX2 tumors broadcast into the liver were used. Changes in contrast-enhanced sonograms were evaluated by real-time observation (FR 15 Hz) of harmonic imaging under extra-low MI (MI 0.065) with Definity, and their intensity changes were analyzed. Hepatic angiography (4/10) and histopathological examination (10/10) were performed to investigate the tumor vascularity. VX2 tumors were hypervascular on angiogram (4/10) and histology (10/10). They showed time-related sonographic appearance changes from hyperechoic to hypoechoic, which were confirmed by quantitative intensity analysis. Hypervascular VX2 tumors showed characteristic time-related shift on contrast-enhanced sonograms in real-time and extra-low MI harmonic images with Definity. These findings may be useful for the ultrasound diagnosis of human hypervascular liver tumor like hepatocellular carcinoma with blood-pool contrast agent.European Journal of Radiology 11/2005; 56(1):60-5. · 2.61 Impact Factor
Top co-authors
Top Journals
Institutions
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2013
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Toshiba Corporation
Tokyo, Tokyo-to, Japan
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2008–2012
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Toshiba Medical Systems Corporation
Tokyo, Tokyo-to, Japan
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2011
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Toho University
- Division of Gastroenterology and Hepatology
Funabashi, Chiba-ken, Japan
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2007–2008
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Tokyo Medical University
- Department of Gastroenterology and Hepatology
Tokyo, Tokyo-to, Japan
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