Kupffer Imaging by Contrast-Enhanced Sonography With Perfluorobutane Microbubbles Is Associated With Outcomes After Radiofrequency Ablation of Hepatocellular Carcinoma.

OBJECTIVES: An ultrasound contrast agent consisting of perfluorobutane microbubbles (Sonazoid; Daiichi Sankyo, Tokyo, Japan) accumulates in Kupffer cells, which thus enables Kupffer imaging. This study aimed to elucidate the association of defect patterns of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography with outcomes after radiofrequency ablation (RFA). METHODS: For this study, 226 patients with initial hypervascular hepatocellular carcinoma, who could be evaluated by contrast-enhanced sonography with Sonazoid before RFA, were analyzed. Patients were divided into 2 groups according to the tumor defect pattern during the Kupffer phase. The irregular-defect group was defined as patients with hepatocellular carcinoma that had a defect with an irregular margin, and the no-irregular-defect group was defined as patients with hepatocellular carcinoma that had either a defect with a smooth margin or no defect. Critical recurrence was defined as more than 3 intrahepatic recurrences, vascular invasion, dissemination, or metastasis. RESULTS: The irregular-defect and no-irregular-defect groups included 86 and 140 patients, respectively, and had cumulative 5-year critical recurrence rates of 49% and 17% (P < .01). Multivariate analysis indicated that the tumor diameter, lens culinaris agglutinin- reactive α-fetoprotein level, and defect pattern were independent factors related to critical recurrence. The cumulative 5-year overall survival rates for the irregular-defect and no-irregular-defect groups were 46% and 61% (P< .01). Multivariate analysis indicated that the Child-Pugh class, tumor diameter, lens culinaris agglutinin-reactive α-fetoprotein level, and defect pattern were independent factors related to survival. CONCLUSIONS: The defect pattern of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography is associated with critical recurrence and survival after RFA.

Kupffer phase image of Sonazoid-enhanced US is useful in predicting a hypervascularization of non-hypervascular hypointense hepatic lesions detected on Gd-EOB-DTPA-enhanced MRI: a multicenter retrospective study.

BACKGROUND: It remains unknown whether Kupffer-phase images in Sonazoid-enhanced ultrasonography (US) can be used to predict hypervascularization of borderline lesions. Therefore, we aimed to clarify whether Kupffer-phase images in Sonazoid-enhanced ultrasonography can predict subsequent hypervascularization in hypovascular borderline lesions detected on hepatobiliary-phase gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging. METHODS: From January 2008 to March 2012, 616 low-intensity hypovascular nodules were detected in hepatobiliary-phase images of Gd-EOB-DTPA-enhanced MRI at nine institutions. Among these, 167 nodules, which were confirmed as hypovascular by Gd-EOB-DTPA-enhanced MRI and Sonazoid-enhanced US, were evaluated in this study. Potential hypervascularization factors were selected based on their clinical significance and the results of previous reports. The Kaplan-Meier model and log-rank test were used for univariate analysis and the Cox regression model was used for multivariate analysis. RESULTS: The cumulative incidence of hypervascularization of borderline lesions was 18, 37, and 43 % at 1, 2, and 3 years, respectively. Univariate analyses showed that tumor size (p = 0.0012) and hypoperfusion on Kupffer-phase images in Sonazoid-enhanced US (p = 0.004) were associated with hypervascularization of the tumor. Multivariate analysis showed that tumor size [HR: 1.086, 95 % confidence interval = 1.027-1.148, p = 0.004] and hypo perfusion on Kupffer-phase images [HR: 3.684, 95 % confidence interval = 1.798-7.546, p = 0.0004] were significantly different. CONCLUSIONS: Kupffer-phase images in Sonazoid-enhanced US and tumor diameter can predict hypervascularization of hypointense borderline lesions detected on hepatobiliary-phase Gd-EOB-DTPA-enhanced MRI.

Hyperenhanced Rim Surrounding Liver Metastatic Tumors in the Postvascular Phase of Sonazoid-Enhanced Ultrasonography: A Histological Indication of the Presence of Kupffer Cells.

AIM: A hyperenhanced rim (termed 'HER') in the postvascular phase is detected in some cases of liver metastasis by Sonazoid-enhanced ultrasonography (US). Here, the association of the HER with histological features was investigated to clarify the cause of this characteristic imaging pattern. SUBJECTS AND METHODS: A total of 13 hepatic nodules obtained from 11 patients with metastatic liver cancer who underwent Sonazoid-enhanced US followed by surgical resection were analyzed. The distribution density of CD68-positive cells in the tumor rim and the nontumor area was calculated and compared between the HER-positive and HER-negative groups. The relation between the pathological features of the tumor rim and the rate of necrosis within the tumor was also investigated. RESULTS: In the HER-positive group (n = 8), the distribution density of CD68-positive cells was 2.9 ± 0.9, which was significantly higher than that (1.0 ± 0.3) in the HER-negative group (p < 0.05). Inflammatory cell infiltrates, including CD8-positive lymphocytes, were detected in all the HER-positive cases in the area surrounding the tumor, while fibrosis was observed in all the HER-negative cases. The necrotic area within the tumor was significantly larger in the HER-negative group. CONCLUSION: The HER-positive sign in liver metastases could reflect an increase in Kupffer cells in the tumor rim. The presence of the HER was associated with inflammatory cell infiltrates including CD8-positive lymphocytes surrounding the metastatic liver tumor.

Diagnosis of hepatocellular carcinoma nodules in patients with chronic liver disease using contrast-enhanced sonography: usefulness of the combination of arterial- and kupffer-phase enhancement patterns.

OBJECTIVES: To determine the usefulness of contrast-enhanced sonography using the perfluorobutane contrast agent Sonazoid (Daiichi-Sankyo, Tokyo, Japan) for establishing the diagnosis and cellular differentiation of hepatocellular carcinoma in patients with chronic liver disease. METHODS: Patients with chronic liver disease in whom hepatic nodules were detected during screening for hepatocellular carcinoma were examined by imaging modalities, including contrast-enhanced computed tomography (CT), contrast-enhanced sonography, and contrast-enhanced magnetic resonance imaging. Nodules with negative imaging findings were further investigated with core biopsy or followed at our hospital. Between April 2007 and March 2011, all patients with hepatic nodules who underwent core biopsy of the nodules or hepatic resection for hepatocellular carcinoma were reviewed. Fifty-nine nodules from 47 patients with 42 contrast-enhanced sonographic findings and 41 contrast-enhanced CT findings were examined. Arterial- and Kupffer-phase enhancement patterns of the nodules on contrast-enhanced sonography were compared with the diagnosis and cellular differentiation of hepatocellular carcinoma. Arterial- and late-phase enhancement patterns on contrast-enhanced CT were also compared with histologic findings. RESULTS: The combination of hyperenhancement in the arterial phase and hypoenhancement in the Kupffer phase on contrast-enhanced sonography (n = 11) correlated with moderately differentiated hepatocellular carcinoma (P = .0028, Fisher exact test). The combination of hypoenhancement in the arterial phase and isoenhancement in the Kupffer phase on contrast-enhanced sonography (n = 14) correlated with well-differentiated hepatocellular carcinoma (P = .0006, Fisher exact test). The combination of high density in the arterial phase and low density in the late phase on contrast-enhanced CT (n = 21) correlated with moderately differentiated hepatocellular carcinoma (P = .0059, Fisher exact test), but no enhancement pattern combination on contrast-enhanced CT correlated with well-differentiated hepatocellular carcinoma. CONCLUSIONS: Sonazoid contrast-enhanced sonography is useful for diagnosis of well-differentiated hepatocellular carcinoma.

Real-time contrast-enhanced sonographically guided biopsy or radiofrequency ablation of focal liver lesions using perflurobutane microbubbles (sonazoid): value of Kupffer-phase imaging.

OBJECTIVES: To evaluate the utility of Kupffer-phase imaging by real-time contrast-enhanced sonography using the perflurobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in guiding biopsy or radiofrequency (RF) ablation of focal liver lesions. METHODS: A total of 75 patients (mean age, 59.7 years) who were referred for percutaneous biopsy (n = 42) or RF ablation (n = 33) were included in the study. Grayscale sonography and contrast-enhanced sonography using Sonazoid were performed in all patients before the procedure. The conspicuity of each targeted liver lesion on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography was graded using a 5-point scale. Lesion detection rates were calculated, and the conspicuity of the lesions among the imaging modalities was compared. The technical success of the procedures was also assessed. RESULTS: The procedures were conducted in 66 patients (biopsy in 41 and RF ablation in 25) under real-time guidance by Kupffer-phase contrast-enhanced sonography. Lesion detection rates were 77.3% (58 of 75), 84.0% (63 of 75), and 92.0% (69 of 75) on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography, respectively, and were significantly different among the 3 modalities (P= .034). Overall, lesion conspicuity was significantly increased on vascular-phase and Kupffer-phase contrast-enhanced sonography compared to grayscale sonography (P < .001). Technical success rates for the procedures were 95.2% (40 of 42) for biopsy and 69.7% (23 of 33) for RF ablation. CONCLUSIONS: Kupffer-phase imaging by contrast-enhanced sonography using Sonazoid increases the conspicuity of the liver lesions compared to grayscale sonography, and it is useful for real-time guidance of percutaneous biopsy or RF ablation of focal liver lesions.

New malignant grading system for hepatocellular carcinoma using the Sonazoid contrast agent for ultrasonography.

BACKGROUND: The ultrasonography contrast agent Sonazoid provides parenchyma-specific contrast imaging (Kupffer imaging) based on its accumulation in Kupffer cells. This agent also facilitates imaging of the fine vascular architecture in tumors through maximum intensity projection (MIP). We examined the clinical utility of the malignancy grading system for hepatocellular carcinoma (HCC) using a combination of 2 different contrast-enhanced ultrasonography images. METHODS: We studied 121 histologically confirmed cases of HCC (well-differentiated, 45; moderately differentiated, 70; poorly differentiated, 6). The results of Kupffer imaging were classified as (1) iso-echoic pattern or (2) hypo-echoic pattern. The MIP patterns produced were classified into one of the following categories: fine, tumor vessels were not clearly visualized and only fine vessels were visualized; vascular, tumor vessels were visualized clearly; irregular, tumor vessels were thick and irregular. Based on the combined assessment of Kupffer imaging and the MIP pattern, the samples were classified into 4 grades: Grade 1 (iso-fine/vascular), Grade 2 (hypo-fine), Grade 3 (hypo-vascular), and Grade 4 (hypo-irregular). RESULTS: The distribution of moderately and poorly differentiated HCCs was as follows: Grade 1, 4 % (1/24); Grade 2, 52 % (15/29); Grade 3, 85 % (44/52); and Grade 4, 100 % (16/16). The grading system also predicted portal vein invasion in 72 resected HCCs: Grade 1, 0 % (0/4); Grade 2, 13 % (1/8); Grade 3, 23 % (11/48); and Grade 4, 67 % (8/12). CONCLUSIONS: This new malignant grading system is useful for estimation of histological differentiation and portal vein invasion of HCC.

Usefulness of contrast-enhanced intraoperative ultrasound using Sonazoid in patients with hepatocellular carcinoma.

OBJECTIVE: To assess the usefulness of contrast-enhanced intraoperative ultrasound (CE-IOUS) using Sonazoid (gaseous perflubutane) in patients with hepatocellular carcinoma (HCC). BACKGROUND: Contrast-enhanced intraoperative ultrasound using Sonazoid, a novel ultrasonic contrast agent enabling Kupffer imaging, may enable differentiation of HCC among new focal liver lesions found during fundamental intraoperative ultrasound (fundamental-NFLLs). METHODS: Between February 2007 and February 2009, a total of 192 consecutive patients were enrolled. Fundamental intraoperative ultrasound and CE-IOUS were performed successively after laparotomy. The vascularity of 1 representative lesion was examined in harmonic mode for approximately 1 minute after the intravenous injection of Sonazoid (vascular phase). Approximately 15 minutes after the vascular phase, total liver scanning in the harmonic mode was commenced (Kupffer phase). One additional injection of Sonazoid was allowed to examine the vascularity of another lesion, if necessary. A tentative diagnosis of HCC was made when a lesion was either hypervascular during the vascular phase or hypoechoic during the Kupffer phase. A final diagnosis of HCC was made on the basis of the results of a histological examination or dynamic computed tomography findings obtained during the 12-month postoperative period. RESULTS: Seventy-nine fundamental-NFLLs were found in 50 patients (26%), 17 (22%) of which were finally diagnosed as HCC. The sensitivity, specificity, and accuracy of CE-IOUS for differentiating HCC among fundamental-NFLLs were 65%, 94%, and 87%, respectively. Contrast-enhanced intraoperative ultrasound identified 21 additional new hypoechoic lesions in 16 patients, of which 14 lesions (67%) in 11 patients were finally diagnosed as HCC. This prospective study protocol was approved by the institutional review board of the Tokyo University Hospital. An English-language summary of the protocol was submitted (registration ID: UMIN000003046) to the Clinical Trials Registry managed by the University Hospital Medical Information Network in Japan (http://www.umin.ac.jp/ctr/index.htm). CONCLUSIONS: With help of CE-IOUS using Sonazoid, more accurate intraoperative staging for HCC can be performed.

Assessment of hepatocellular carcinoma by contrast-enhanced ultrasound with perfluorobutane microbubbles: comparison with dynamic CT.

OBJECTIVE: The aim of this study was to evaluate tumour vascularity and Kupffer cell imaging in hepatocellular carcinoma (HCC) using contrast-enhanced ultrasonography (CEUS) with Sonazoid (perfluorobutane) and to compare performance with dynamic CT. METHODS: We studied 118 nodules in 88 patients with HCC. HCC was diagnosed as a hyperenhancement lesion in the arterial phase with washout in the portal phase on dynamic CT or by percutaneous biopsy. We observed tumour vascularity at the early vascular phase (10-30 s after contrast injection) and Kupffer imaging at the post-vascular phase (after 10 min). RESULTS: Detection of vascularity at the early vascular phase was 88% in nodules that were found to be hypervascular on dynamic CT and 28% in hypo-/isovascular nodules; the detection of local recurrence nodules was 92%. The detection of vascularity was significantly lower in nodules >9 cm deep than in those ≤9 cm deep, but was not affected by tumour size. The detection of tumours at the post-vascular phase on CEUS was 83% in nodules with low density in the portal phase on dynamic CT and 82% in nodules with isodensity. The rate did not depend on the severity of underlying liver disease; rates decreased in nodules deeper than 9 cm, those smaller than 2 cm in diameter and in iso-enhancing nodules at the early vascular phase of CEUS. CONCLUSION: CEUS with Sonazoid is a useful tool for assessing the vascularity of HCC and is equal to that of dynamic CT; however, the detectability of HCC vascularity is affected by location.

Utility of contrast-enhanced ultrasonography with Sonazoid in radiofrequency ablation for hepatocellular carcinoma.

BACKGROUND AND AIMS: Kupffer imaging in contrast-enhanced ultrasonography (CEUS) with Sonazoid, which lasts for 60 min or longer, may be useful in ultrasound-guided percutaneous tumor ablation. The utility of Sonazoid in radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) was investigated in this study. METHODS: We analyzed a total of 716 HCC nodules that were detected on dynamic computed tomography in 316 patients. Detectability of these nodules was compared between CEUS and conventional ultrasonography. The effectiveness in the treatment was assessed by comparing the mean numbers of treatment sessions of RFA in patients treated with CEUS and that in historical controls matched for tumor and background conditions. RESULTS: Detectability of tumor nodule was 83.5% in conventional ultrasonography and 93.2% in CEUS (P=0.04). Sixty-nine nodules in 52 patients were additionally detected with CEUS. The number of additionally detected tumor nodules was positively correlated with serum albumin level (P=0.016). The number of RFA sessions was 1.33±0.45 with CEUS as compared to 1.49±0.76 in the historical controls (P=0.0019). CONCLUSIONS: CEUS with Sonazoid is useful for HCC detection in patients with a well-conserved liver function reservoir. The decrease in RFA session numbers indicated the utility of Sonazoid in RFA treatment of HCC.

Definition of contrast enhancement phases of the liver using a perfluoro-based microbubble agent, perflubutane microbubbles.

To define the contrast enhancement phases in the liver with perflubutane microbubbles, the liver enhancement time-intensity curves were investigated in 14 healthy volunteers. The agent was injected intravenously as a bolus and the liver was imaged with an ultrasound scanner as long as 4h after the injection. Time-intensity curves from the hepatic artery, the intrahepatic portal vein, the hepatic vein and the parenchyma of the liver were obtained from the liver ultrasound images. The arrival of the agent in the hepatic artery, the portal vein and the hepatic vein were visually distinguishable and the mean arrival times were 19.2, 24.3 and 32.2 s after the injection, respectively. The signal intensity in these vessels increased rapidly after the arrival of the contrast and gradually reverted to baseline after the peak. In contrast, within 5 min after the injection, the intensity in the parenchyma increased and reached a plateau, which persisted for at least 2h. The contrast enhancement phases in the liver with perflubutane microbubbles could be defined as two major phases-a vascular phase, in which the vessels are enhanced between 15 s and 10 min after injection, and a Kupffer phase, in which the parenchyma is enhanced 10 min after injection. The vascular phase is divided into three subphases: the arterial phase (15 to 45 s after injection); the portal phase (45 s to 1 min after injection); and the vasculo-Kupffer phase (1 to 10 min after injection).

A detailed examination of pulmonary uptake of (99m)Tc-Tin colloid in healthy mature miniature pigs.

(99m)Tc-Tin colloid is a commonly used colloidal radiopharmaceutical in human medicine for evaluating liver function and morphology. (99m)Tc-Tin colloid is taken up in the liver by the phagocytic activity of Kupffer cells, the reticuloendothelial cells of the liver. Unlike what occurs in human beings, we demonstrated (99m)Tc-Tin colloid uptake within the lungs and liver in healthy, mature, miniature pigs. Our observations may be explained by the presence of pulmonary intravascular macrophages (PIMs) closely apposed to the endothelium of the pulmonary capillaries in several animal species, such as the sheep, horse, goat, cat and pig. In the current study, we compared scintigraphic images using (99m)Tc-Tin colloid in rats with those in mature, miniature pigs, and identified the presence of PIMs, reticuloentothelial cells similar to Kupffer cells, by immunohistochemistry in pigs. Pulmonary uptake of (99m)Tc-Tin colloid occurred only in pigs, and PIMs in the pulmonary capillaries stained positively for mouse monoclonal MAC387 antibodies to macrophages in lung sections, as well as Kupffer cells in liver sections. Therefore, we conclude that the uptake of intravenously injected (99m)Tc-Tin colloid within both Kupffer cells and PIMs results in scintigraphic imaging of the lung and liver in miniature pigs.

Portal hyperfusion or hepatic venous congestion: which one affects Kupffer cell function more?

OBJECTIVES: Because of their effects on the liver parenchyma after surgery, portal hyperperfusion and hepatic venous congestion are challenging problems for hepatobiliary surgeons. However, the effects of those conditions on Kupffer cells have not been established. The aim of this study was to investigate the effects of vascular streams modified by portal hyperperfusion and hepatic venous congestion on Kupffer cell function. MATERIALS AND METHODS: Thirty rats were allocated into 3 groups of 10 rats each and were subjected to right portal vein ligation to induce hyperperfusion in the left lobe of the liver (group 1), occlusion of the right hepatic vein to produce venous congestion (group 2), or sham operation (controls; group 3). After 72 hours, the right and left liver lobes of the subjects were submitted separately for scintigraphic and histopathologic evaluation, and the radiocolloid uptake per gram of liver tissue and the number of Kupffer cells per square millimeter were calculated. RESULTS: The mean technetium-99m labeled sulfur colloid uptake values of the liver tissue per gram were 0.126 -/+ 0.038 for group 1, 0.106 -/+ 0.032 for group 2, and 0.110 -/+ 0.031 for group 3. Portal hyperperfusion significantly increased the technetium-99m labeled sulfur colloid uptake of the liver tissue per gram (P = .043). The mean number of Kupffer cells per square millimeter was calculated for each group as follows: 321 -/+ 094 x 10-6 for group 1, 369 -/+ 083 x 10-6 for group 2, and 355 -/+ 096 x 10-6 for group 3. Both vascular streams produced no significant effects on the number of Kupffer cells (P > .05). CONCLUSIONS: In this experimental model, portal hyperperfusion affected Kupffer cell function more than did hepatic venous congestion.

Optical microscopic findings of the behavior of perflubutane microbubbles outside and inside Kupffer cells during diagnostic ultrasound examination.

PURPOSE: To investigate the behavior of perflubutane microbubbles outside and inside Kupffer cells during diagnostic ultrasound (US) examination, and to determine the thresholds of the acoustic pressure of different kinds of behavior. METHODS: Acoustic behavior of perflubutane microbubbles inside and outside Kupffer cells in an acoustic field induced by a clinical US transducer and equipment was optically observed in vitro. The acoustic pressure was measured simultaneously by a calibrated hydrophone and an oscilloscope. RESULTS: The acoustic behavior of microbubbles was optically categorized as stabilization, oscillation, transposition, shrinkage, and destruction. The mechanical index (MI) displayed on the US equipment correlated well with the acoustic pressure at the level of microbubbles measured hydrophonically. At a frame rate of 15 Hz with a frequency of 3.5 MHz and pulse repetition frequency of 3 KHz, the thresholds in term of MI for free microbubbles to begin oscillation, reach best oscillation, transposition, shrinkage, and destruction were 0.21, 0.44, 0.53, 0.75, and 1.03, respectively. Although adherent and phagocytosed microbubbles showed more stability enduring insonation compared with free microbubbles, the thresholds of shrinkage and destruction were MI 1.03 and 1.18 for adherent microbubbles, and 1.18 and 1.37 for phagocytosed microbubbles, respectively. Neither oscillation nor transposition of microbubbles inside Kupffer cells was observed microscopically. No cell damage because of microbubbles destruction was found in the present study. CONCLUSION: Perflubutane microbubbles outside and inside Kupffer cells respond to external US insonation with same parameters of a clinical contrast-enhanced US study according to the acoustic pressure. Free microbubbles behave as stabilization, oscillation, transposition, shrinkage, and destruction under insonation. The adherent and phagocytosed microbubbles are more stable under insonation than free microbubbles, but still respond showing shrinkage and destruction when MI is over 1.03.

Differential diagnosis of hepatic tumors: value of contrast-enhanced harmonic sonography using the newly developed contrast agent, Sonazoid.

OBJECTIVE: To clarify the value of contrast-enhanced harmonic ultrasonography (US) with Sonazoid, a second-generation US contrast agent, in the differential diagnosis of liver tumors compared to dynamic CT. METHODS: A total of 249 hepatic nodules in 214 patients were studied; these included 177 hepatocellular carcinomas (HCCs), 42 liver metastases, 20 liver hemangiomas, 6 dysplastic nodules and 4 focal nodular hyperplasias (FNHs). After the injection of Sonazoid, nodules were scanned using real-time contrast-enhanced harmonic US in the vascular phases, i.e. the early and late vascular phases, and the Kupffer phase. RESULTS: Six enhancement patterns were identified to be significant for the differential diagnosis of hepatic tumors. In HCCs, the presence of intratumoral vessels supplied from the periphery and fast washout (sensitivity, 96.6%; specificity, 94.4%) were the most typical characteristics. In metastases, the presence of rim-like enhancement with peripheral tumor vessels (sensitivity, 88.1%; specificity, 100%) was the typical pattern. In hemangiomas, the presence of intratumoral hypoperfusion images with globular or cotton wool-like pooling, which continue to the late vascular phase (sensitivity, 90.0%; specificity, 99.6%), was typical. In dysplastic nodules, the presence of portal enhancement without arterial supply in the early vascular phase and the presence of intratumoral uptake in the Kupffer phase (sensitivity, 83.3%; specificity, 100%) were the most typical patterns. In FNHs, the presence of a spoke-wheel pattern in the early vascular phase with dense staining in the late vascular phase, and positive uptake within the nodule in the Kupffer phase (sensitivity, 100%; specificity, 100%) were the most typical patterns. CONCLUSION: Contrast-enhanced harmonic US with Sonazoid allowed intimate vascular and Kupffer imaging and, therefore, is useful for the differential diagnosis of hepatic tumors.

Differential receptor targeting of liver cells using 99mTc-neoglycosylated human serum albumins.

Neolactosyl human serum albumin (LSA) targets asialoglycoprotein receptor and shows high liver uptake due to accumulation in hepatocytes. Although neomannosyl human serum albumin (MSA) also shows high liver uptake, it has been reported to be taken up by Kupffer cells and endothelial cells. We compared the biological properties of LSA and MSA. 99mTc-LSA and 99mTc-MSA biodistribution in mice were investigated after intravenous injection. In vivo localization of rhodaminisothiocyanate (RITC)-LSA and fluoresceineisothiocyanate (FITC)-MSA were investigated in mouse liver. Excretion routes of 99mTc-LSA and 99mTc-MSA metabolites were examined. Both 99mTc-LSA and 99mTc-MSA showed high liver uptakes. RITC-LSA was taken up by hepatocytes whereas FITC-MSA was taken up by Kupffer cells and endothelial cells. 99mTc-MSA showed higher spleen and kidney uptakes than 99mTc-LSA. 99mTc-LSA metabolites excreted in urine and feces accounted for 44.4 and 50.0% of 99mTc-LSA injected, respectively, while 99mTc-MSA metabolites accounted for 51.5 and 10.3%, respectively. In conclusion, LSA is specifically taken up by hepatcytes while MSA by Kupffer cells and endothelial cells. After taken up by the liver, LSA is metabolized by the hepatocytes and then excreted through both the hepatobiliary tract and kidney, whereas MSA is metabolized by Kupffer cells and endoghelial cells and then excreted mainly through the kidney.

Mechanism of hepatic parenchyma-specific contrast of microbubble-based contrast agent for ultrasonography: microscopic studies in rat liver.

OBJECTIVE: The objective of this study was to elucidate the mechanism of hepatic parenchyma-specific contrast of Sonazoid (microbubble contrast agent) using microscopic techniques. MATERIALS AND METHODS: Sonazoid was intravenously injected into rats to investigate the microbubble dynamics and distribution within hepatic microcirculation in exteriorized liver using intravital microscopy and to observe dose dependency of ultrasound hepatic contrast effect. In vitro and in vivo uptake of microbubbles by Kupffer cells was examined using confocal laser scanning microscopy. RESULTS: Intravital observation demonstrated freely flowing microbubbles in the sinusoid and some microbubbles co-localized with Kupffer cells. The microbubbles internalized in Kupffer cells were identified with reflected light by confocal laser scanning microscopy. The percentage of Kupffer cells taking up microbubbles was about 1% at clinical dose at which the homogeneous hepatic contrast was observed. CONCLUSIONS: The hepatic parenchyma-specific contrast by Sonazoid is due to distribution of the microbubbles in Kupffer cells.

Phagocytosis of ultrasound contrast agent microbubbles by Kupffer cells.

Delayed parenchymal phase images of the liver more than 5 min after IV injection of ultrasound contrast agents are thought to be related to the phagocytosis of contrast agent microbubbles by macrophages. In this study, we examined whether liver-specific macrophages, Kupffer cells, phagocytosed the microbubbles and whether their elimination affected the delayed parenchymal images of the liver. Phase-contrast microscope observations showed that Kupffer cells phagocytosed various contrast agents in vitro. Among the contrast agents used, 99% of Sonazoid and Optison, and 47% of Levovist were phagocytosed, whereas only 7.3% of SonoVue and 0% of Imavist were phagocytosed. Elimination of Kupffer cells in vivo by gadolinium chloride (GdCl(3)) resulted in decreased intensity of the delayed parenchymal images with Sonazoid and Levovist, while SonoVue showed no changes compared with control. Our findings suggested that Kupffer cells phagocytosed contrast agents and they were responsible for the delayed images of contrast ultrasound in the liver.

Hepatic tumor detection: MR imaging and conventional US versus pulse-inversion harmonic US of NC100100 during its reticuloendothelial system-specific phase.

PURPOSE: To compare conventional ultrasonography (US) and magnetic resonance (MR) imaging with contrast agent-enhanced US for detection of VX-2 liver tumors in rabbits. MATERIALS AND METHODS: Conventional gray-scale liver US was performed in 65 rabbits, 38 of which had VX-2 hepatic tumor implants. Twenty minutes after contrast agent injection, gray-scale pulse-inversion harmonic US images of the liver-specific phase were obtained. Following sacrifice of the animals, T1- and T2-weighted MR imaging was performed at 4-mm intervals. Pathologic analysis was performed as the reference standard. The capability of each imaging modality to correctly depict tumor presence or absence and the number of tumors was compared. RESULTS: Conventional US correctly depicted the presence or absence of tumors in 54 rabbits, for an accuracy of 83%, sensitivity of 71%, and specificity of 100%. With contrast-enhanced US, accuracy increased to 92% (60 correct cases); sensitivity, to 87%; and specificity, to 100%. MR imaging facilitated 56 correct diagnoses, for an accuracy of 86%, sensitivity of 82%, and specificity of 93%. There was a marginally significant difference between US with and US without contrast agent (P =.07) but not between MR imaging and contrast-enhanced US (P > or = .34). When the numbers of correctly detected tumors were compared, contrast-enhanced US performed significantly better than MR imaging (P =.02) and conventional US (P =.04). CONCLUSION: There was no significant difference between contrast-enhanced US and MR imaging in the detection of hepatic tumors, whereas contrast-enhanced US had the highest accuracy (92%) of the three modalities studied.

Ultrastructure of Chronic Liver Diseases ; Kupffer Cells of the Hepatic Sinusoids / 대한간학회지

No abstract available.