P-1 Synthesizing cationic microbubbles for improving ...jabts.umin.jp/jabts32/acuci2014/dl/Abstract_p.pdfwith the concentration of cationic MBs (1-50μL) and the exposure time of US

The 6th Asian Conference on Ultrasound Contrast Imaging (ACUCI 2014) 第6回アジア造影超音波会議（ACUCI 2014）

58

P-1 Synthesizing cationic microbubbles for improving ultrasound-triggered and targeted gene delivery

Chien-Yu Ting, Chung-Hsin Wang, En-Ling Chang, Chih-Kuang Yeh

Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University

Currently, both viral and non-viral vectors are widely used systems to achieve selectively and targeted gene therapy. The formers are recognized with high efficiency of gene delivery, however their immunogenicity and potential mutagenicity restricted further clinical applications. Although non-virus carriers perform significantly less efficiency in vivo, they are attractive alternatives to viral vectors for their multi-function capability and lack of specific immune response, providing better reliability in the clinical settings. Recently, ultrasound (US)-targeted microbubbles (MBs) destruction has been validated as a non-invasive, effective, and the most importantly, safe technique for gene transfection. MBs serve as not only the gene carriers which prevent gene structures from hydrolyzation in vivo, but also US contrast agents which assist the monitoring of gene delivery by US imaging. In this study, we synthesized a positively charged MB with a greater DNA binding capacity to enhance the targeted gene transfection efficiency and simultaneously minimize toxicity by the trigger of US.

Cationic MBs were composed of phospholipid and C3F8 gas core, and were obtained by cooperating with Trust Biosonics, Inc. (Hsinchu, Taiwan). The concentration, size distribution, and zeta potential of MBs were (2.5±0.2) ×1010/mL, 1.12±0.12μm, +55±5.1 mV measured by Multisizer® and Nanosizer-S, respectively. C-6 glioma cells were used as targeted cells. Calcein, a hydrophilic fluorescent molecule, was utilized as a model drug for quantifying the role of promoting transport of gene structures by flow cytometry. A 3-MHz ultrasound transducer with 1.1 MPa, 10-30 % duty cycle was applied for triggering Calcein delivery into the cells. The cytotoxicity of cells was also examined via Alarmar blue assay.

The surface charge of typical MBs was initially negative (-15mV). Following addition of cationic phospholipid materials, the zeta potential of the fabricated cationic MBs was shifted to positive values, and was significant for DNA binding through the electrostatic interactions. The Calcein transportation capacity increased in proportion with the concentration of cationic MBs (1-50μL) and the exposure time of US (30-120 sec). Fluorescent transfection of C-6 cells using 30μL of cationic MBs combined with 2 min ultrasound exposure yielded 46.2±5.7%, which was 6.5-fold higher than untreated cells. However, the cytotoxicity after treatment also increased with MB concentration. The cell viability after 24 hours were evaluated to be 97.2±5.7% and 76.9±4.3% for untreated cells and cells treated with cationic MBs, individually.

Our study demonstrated the feasibility of using novel cationic MBs with the US sonication to efficiently deliver the genes to target site. This cationic MB was able to increase DNA loading capacity that could promote the gene transfection efficiency. Future works include loading therapeutic gene fragments abundantly onto the surface of cationic MBs for US-mediated gene therapy on gene-defected models.

Keywords:Gene therapy, cationic microbubbles, ultrasound　


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P-2 An ultrasound contrast medium delivery system by carotid artery catheterization in a rat liver tumor model

Cheng-In Hoi1), Ran-Chou Chen1,4), Wei-Hsiu Chiu1,2,3), Yu-Syuan Liao1), Yu-Yo Hsiao4), Wei-Tsung Chen4)

1) Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan 2) 1st Clinical Medical College, Jinan University, Guangzhou, China 3) Department of Obstetrics and Gynecology, Chung Shan Hospital, Taiwan 4) Department of Radiology, Taipei City Hospital, Taiwan

PurposeThe aim of this study is to develop an optimal delivery system that can deliver contrast medium conveniently to liver by using carotid artery catheter.Materials and MethodsAn anesthetized rat which was inserted catheter through the carotid artery towards the heart about 15~20mm. The catheter was advanced approach to celiac trunk of proximal abdominal aorta. The rat was grafted GP7TB tumor cells (1x107) in the left liver lobe. The CO2 pure gas (2 c.c.) was injected from carotid artery. The transducer was placed on rat liver to observe xenograft tumor. Ultrasound was used to detect contrast medium flow into rat liver.

ResultsA stable drug delivery system was developed by using carotid artery catheter that can inject contrast medium to liver. A rat liver xenograft tumor model was also built. The CO2 gas injected from the catheter can successfully flush into the rat liver and detect the tumor vessels and delineate the tumor extension.

ConclusionOur study showed that an optimal drug delivery system was developed. It was feasible and steady for ultrasound contrast-enhanced imaging study in a rat liver xenograft tumor model.


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P-3 SPIO-DOX complex loaded microbubbles for concurrent MRI imaging and ultrasound-based drug delivery

Ching-Hsiang Fan1), Yu-Hang Cheng1), Hao-Li Liu2), Chih-Kuang Yeh1)

1) Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University 2) Department of Electrical Engineering, Chang-Gung University

Focused ultrasound (FUS) in the presence of microbubbles (MBs) has been approved to induce local and temporal blood-brain barrier disruption (BBBD), increasing therapeutic agents into brain. However, it is difficult to evaluate the amount and distribution of chemotherapeutic agents within brain after BBBD. Recently, the superparamagnetic iron oxide (SPIO) contrast-enhanced MR susceptibility-weighted imaging (SWI) performed the negative contrast enhancement at BBBD site. This study proposed a therapeutic complex which conjugated SPIO nanoparticle with doxorubicin (DOX), and was modulated on the lipid shell of MBs (SDMBs). During FUS sonication, DSMBs can simultaneously achieve BBBD and delivery the SPIO-DOX complexes into brain tissue. At the same time, the release and distribution of the DOX can be tracked via the contrast of SPIO in MR imaging.

The DOX molecular and 9 nm SPIO particles were conjugated via amino group and carbonyl group. These SPIO-DOX complexes were then loaded onto the lipid surface of MBs by hydrophobic interaction. The mean size and concentration of SDMBs were 1.4 µm and (1.5–2.0) ×109 bubble/mL, respectively. The payload of DOX and SPIO were 1.0 mg and 1.0 mg by spectrometer and ICP-AES, individually. Four Sprague-Dawley rats were used in this study. FUS (frequency=1 MHz, energy=0.7 MPa, duty cycle=10%, sonication=90 sec) was performed following SDMB injection. The BBBD region was confirmed by Evans blue staining. The deposition of SPIO and DOX were monitored by MR SWI images and fluorescent microscope, respectively.

In vitro studies exhibited that the SPIO accumulation area showed in MR-SWI images correlated considerably to the DOX deposition region in microscope image. By the trigger to FUS, successful BBBD was achieved using SDMBs. Besides, SDMBs were simultaneously released into the brain tissue and showed significant contrast on MR images and fluorescent microscope.

We confirmed that SDMBs with FUS can locally open the BBB and have the potential to deliver the SPIO-DOX complexes for MR SWI imaging, assessing drug delivery area. Future works include correlating the amount of SPIO on MR images with DOX deposition in brain to real-time estimate the drug delivery process.

Keyword: blood-brain barrier, focused ultrasound, doxorubicin, superparamagnetic iron oxide


61

P-4 Polymer-Phospholipid composite microbubbles for ultrasound drug delivery

Shih-Tsung Kang, Jian-Liang Lin, Chung-Hsin Wang, Chih-Kuang Yeh

Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University

Ultrasound contrast agents are highly echogenic microbubbles providing both diagnostic and therapeutic usefulness. Stable and inertial cavitation of microbubbles have been shown to aid blood brain barrier disruption and drug delivery, whereas inertial cavitation, involving the rapid fragmentation and collapse of microbubbles, has great potential to cause hemorrhage and damage to biological tissue. This study proposed a novel design of microbubbles providing maintained performance in non-linear oscillation but lower propensity to exhibit inertial cavitation under ultrasound exposure. A two-dimensional network structure was incorporated into the lipid monolayer of conventional microbubbles consisting DSPC and DSPE-PEG2000. This network served as a scaffold to stabilize these lipids, rendering the microbubbles more resistant to ultrasound-induced fragmentation and collapse. During the fabrication, the lipids and reactive monomers and crosslinkers were mixed in a vial filled with C3F8 gas. Microbubbles with a mean size of 1.8μm were formed after 45 s of agitation, followed by a polymerization process for 15 min initiated under increased temperature and UV light exposure. Transmission electron microscopy showed the presence of the network structure after removal of the lipids by adding Triton X-100 into the sample in sonication bath. No significant difference in ultrasound resonance frequencies of 10-15 MHz was observed for microbubbles before and after the polymerization. Nevertheless, the stable cavitation dose characterized at 5 MHz was increased by 200% and the inertial cavitation dose was reduced by 25% for the polymerized microbubbles at the same pressure levels. These results suggest that the new design is potential to lower the mechanical index required to achieve the same effectiveness for microbubbles in diagnostic and therapeutic applications, providing higher safety in clinical use.


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P-5 3D contrast-enhanced ultrasound imaging for evaluating the nanobubble-assisted drug delivery

Chung Hsin Wang1,2), Hong-Jen Chiou3), Chih-Kuang Yeh3)

1) Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University 2) Trust Bio-sonics, Inc. 3) Department of Radiology, Taipei-Veterans General Hospital

Background: During the past decade, microbubble-based ultrasound imaging technique has evolved from an investigational tool to a standard diagnostic procedure. Microbubbles show their capabilities in visualizing bloodstream which provides physicians to evaluate the blood perfusion of organs. However, there are seldom studies focusing on the evaluation of microcirculation of tumors because of the lack of a reliable bubble agent capable to defuse to higher interstitial fluid pressure areas. In this study, a nanobubble agent was compared with SonoVue to investigate the potential usefulness of contrast-enhanced ultrasound (CEUS) in osteosarcoma treatment.

Methods: The nanobubble agent was obtained by cooperating with Trust Biosonics, Inc. (Hsinchu, Taiwan). The fabricated nanobubbles have a mean size of 500 nm and the concentration of 3×1010 bubbles/mL. The drug-loaded nanobubble was further prepared by mixing doxorubicin (DOX) with a specific lipid formulation in a concentration of 2 mg/mL under 60°C for 30 min before being activated to bubble solution. Cultured MG 63 human osteosarcoma cells implanted into the tibia site of Nude mice. 3-MHz ultrasound insonations combined with DOX-loaded nanobubble (DOX-NB) administration was delivered to locally release the drugs and facilitate drug permeability. The tumor perfusion before and after the treatment was evaluated by three-dimensional power Doppler (Voluson E8, GE, USA) and contrast harmonic imaging techniques (CHI) (Aplio500, Toshiba, Japan) using a live 4D transducer (14-MHz). The color flow, contrast flow and volume of tumor were analyzed. Three experimental groups including control, DOX-MB without, and with ultrasound-triggered release were comprised for the comparisons (N=6, each).

Results: We have demonstrated that the nanobubble agent is capable to enhance the Doppler power of tumor vessels. Compared with traditional bubble agent, the nanobubble shows its superiority over perfusing into the tumor microcirculation. However, microcirculation or small vessels were hard to be evaluated under Doppler mode due to the effect of bubble destruction (MI=0.4). Through the use of ultra-low MI CHI mode (MI=0.07), the perfusion condition of tumor could be further evaluated. The administration of DOX-NB and ultrasound insonations enhanced the DOX molecules release. The tumor volume suppression was 2.82-fold increase compared with the group without ultrasound insonations. The introduction of DOX-NB and ultrasound insonations led to the substantial necrosis of osteosarcoma tumor in day 5 after treatment. The mean contrast flow dropped to 24.6% compared with the flow before the treatment.

Conclusion: The results revealed that the nanobubble agent is reliable for both cancer diagnosis and therapy, and the use of 3D/4D CHI technique provided a convenient tool to evaluate the tumor therapeutic outcome and might help for tumor treatment planning and new drug discovering.


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P-6 Basic analysis for time constant of blood perfusion with contrast arrival time histogram

Yik Ning Wong1), Masahiko Yano1), Nicolas Rognin2)

1) Toshiba Medical Systems Corporation, Ultrasound Systems Division 2) Toshiba Medical Research Institute USA, Inc

Objective: Parameters of dynamic blood perfusion provide information of changes in liver tumor vasculature and assist physicians in diagnosing and treating tumors. By using contrast enhanced ultrasound imaging (CEUS) and Parametric Micro-Flow Imaging (P-MFI)1), a new method is introduced for analyzing blood perfusion information qualitatively through visualization2). The contrast arrival time histogram acquired by P-MFI can provide the Time Constant (tau,τ) of contrast wash-in properties. Time Constant might be a useful tools for tumor vasculature investigation and differentiating liver tumors.

Methods: CEUS image clips with destruction-replenishment method are collected for the time constant study. P-MFI provides visualization of contrast arrival time information by representing arrival time of each pixel with different colors and allows a better understanding of blood flow pattern. Region of interests (ROIs) are selected and each ROI generates an arrival time histogram by plotting number of colored pixel through contrast arrival versus time. The cumulative density function of arrival time histogram allows the measurement of transient response function and time constant by fitting the exponential equation3) though least square method.

t-tsy(t)=1-e (- τ ) : t > ts, y(t)= 0: t < ts

The time constant is assumed to be related to the blood wash-in perfusion. A rabbit normal liver is used as an example for investigating time constant at different branches of vessel and the spreading speed of contrast agents. An arterial vessel can has more than 10 level of branches from its main stem to capillary vessels, which diameter ranges from 5-10 μm. As blood flow becomes steady and velocity decrease, perfusion rate gradually slows down as bubbles spread in peripheral vessels. The arrival time histogram indicates the distribution ratio of blood flow from main portal vessel to capillary thus we can understand the transient response of contrast wash-in. Time constant at different branches (peripheral vessels) are compared to the overall liver (reference) for demonstrating delayed arrival time at capillaries.

Results: The overall time constant in a Rabbit liver is 0.9 and the time constant for 2 level of braches at the peripheral vessels are 1.02 and 1.42 respectively (Figure 1). Compared to total liver ROI, peripheral vessels tend to have a slightly longer time constant. It showed that there is a rich perfusion and demonstrated the actual blood flow velocity.

Conclusion: We have proposed an innovative method for contrast quantification using histogram method for overall perfusion time. With this method, by investigating the spreading of contrast inside a tumor, we can determine the transient response model with proposed time constant (τ). As a result, we can investigate the stability of blood flow velocity from Main trunk to Periphery blood vessels. For future study, we will investigate the comparison of time constant from different liver tumors. We are looking forward to considering the velocity of contrast agent spreading as one of the parameter for clinical evaluation.

Reference: 1. H. Yoshihara et al. JSUM 82-C-010 2. Shiozawa et al. JMUS Jan 2013, Vol40,pp73-76 3. K. Wei et al. Quantification of myocardial blood flow with ultrasound-induced destruction of microbubble administered as a constant

venous infusion

Figure 1. Stored video clip is passed to P-MFI arrival time histogram program. The program generated histogram which shows the ratio of arrival bubble in an ROI. Time constants are calculated from arrival time histogram. Courtesy of Professor Moriyasu (Tokyo Medical University)


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P-7 Development of molecular targeted-bubbles based on Sonazoid

Kentaro Otani

National Cerebral and Cardiovascular Center Research Institute

Ultrasound molecular imaging with molecular-targeted bubbles enables the noninvasive visualization of molecular dynamics in situ. Although some ultrasound contrast agents have been clinically applied for the vascular/Kupffer imaging, however the clinically translatable molecular-targeted bubble has not been developed until now. The aim of this study was to examine the feasibility of molecular-targeted bubbles preparation based on Sonazoid, a clinically available ultrasound contrast agent in Japan. As Sonazoid is stabilized by a membrane of hydrogenated egg phosphatidylserine (PS), we planned to utilize the PS as a scaffold for attaching IgGs and proteins onto Sonazoid. For detecting PS in Sonazoid, annexin V and lactadherin were utilized. By using biotin-avidin complex formation and annexin X, the attachment of IgG onto the surface of Sonazoid was feasible. However, majority of bubbles were disappeared during the bubbles preparation due to the addition of Ca2+ for maintaining the binding between PS and annexin V. On the other hand, lactadherin was superior to annexin V, because Ca2+ is unnecessary for the binding between PS and lactadherin. Furthermore, the lactadherin-bearing Sonazoid bubbles have an ability to bind with integrin αvβ3-expressing endothelial cells (Figure). Because integrin αvβ3 is well-known to play a key role in angiogenesis, the lactadherin-bearing Sonazoid might have feasibility as a clinically translatable targeted ultrasound contrast agent for angiogenesis.


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P-8 Prognostic value of contrast-enhanced ultrasonography in patients with small hepatocellular carcinoma

Yosui Tamaki, Kazunobu Aso, Mitsuyoshi Okada, Ryuji Sudo, Yu Ota, Ai Takasoe, Yuko Suzuki, Keisuke Yamakita, Masako Imazawa, Yohei Kitano, Masakazu Haneda

Division of Metabolism and Biosynthetic Science, Department of Medicine, Asahikawa Medical University

Background: Gross tumor classification was reported as a prognostic factor after resection of hepatocellular carcinoma (HCC), but it was difficult to classify tumors by dynamic CT before operation. Recent study showed contrast-enhanced ultrasonography (CEUS) with perflubutane microbubble might be a useful tool in the evaluation of the gross type of HCC. The purpose of this study was to investigate the usefulness of CEUS for the prediction of recurrence after the curative therapy of small HCC.

Methods: 1) In order to confirm the accuracy of CEUS for gross findings, we examined 22 resected HCC nodules (9 single nodular types, 8 single nodular types with extranodular growth, and 5 contiguous multinodular types). Gross tumor classification was based on the general rules for the clinical and pathological study of primary liver cancer, 5th edition, established by the Liver Cancer Study Group of Japan. All tumors were divided into 3 types according to CEUS findings. Type 1a was characterized by round like obscure defect in the post-vascular phase. Type 1b was described irregular shaped obscure defect in the post-vascular phase. Type 2 formed aggregated nodules like enhancement in the vascular phases. 2) To investigate the prognostic value of CEUS, we retrospectively enrolled 32 patients (the mean observation period 31.8 months) received a curative therapy against HCC less than 3cm (11 patients underwent hepatectomy and 21 patients radiofrequency ablation since January 2007 to August 2011). Recurrence-free survival time calculated by the Kaplan-Meier method was compared using log-rank test. The predictive factors of recurrence were subjected to univariate and multivariate analysis using Cox's proportional hazards model.

Results: 1) The accuracy of type 1a for single nodular type, type 1b for single nodular type with extranodular growth and type 2 for contiguous multinodular type were 91%, 87% and 95%, respectively. 2) Patients were divided into two groups by CEUS findings before treatment; Type1a (19 cases) and Others (13 cases). Median disease-free survival time and the three year disease free survival rate were 41.4 months and 62.3% in Type1a and 16.8 months and 13.5% in Others. There was significant difference between the two groups (p=0.0048). CEUS classification (p=0.009) and Hyaluronic acid (p=0.037) were significantly associated with recurrence in univariate analysis. Multivariate analysis suggested that CEUS classification was a sole independent predictor (p=0.0301).

Conclusions: CEUS classification in this study was accurate at gross classification of HCC. CEUS may be useful for predicting the recurrence of HCC less than 3cm in diameter before curative therapy.


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P-9 Intraoperative contrast-enhanced ultrasound portography combined with indigo carmine dye injection for anatomical liver resection in hepatocellular carcinoma: A new technique

Yang Shin Park, Chang Hee Lee, Jongmee Lee, Jae Woong Choi, Kyeong Ah Kim, Cheol Min Park

Department of Radiology, Korea University Guro Hospital

We present a method of intraoperative contrast-enhanced ultrasound portography combined with indigo carmine dye injection for an anatomical liver resection in hepatocellular carcinoma. During surgery, prior to dye infusion into the feeding portal vein, the targeted portal vein branch was directly punctured and a microbubble contrast agent was administered under ultrasound guidance. Simultaneous enhancement of the resected hepatic parenchyma using a microbubble contrast agent and blue dye improved estimation of the segmental border in the cutting plane and the tumor resection margin during liver surgery.


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P-10 Comparision of lesion conspicuity between conventional ultrasonography and Sonazoid contrast enhanced ultrasonography (CEUS) as pretreatment evaluation for radiofrequency ablation (RFA) of small hepatocellular carcinomas (HCC) (<3cm and 1.5cm)

Jung Wook Seo, You Sung Kim

Department of Radiology, Inje University Ilsan Paik Hospital

Objective: To compare lesion conspicuity between conventional ultrasonography and Sonazoid contrast enhanced ultrasonography (CEUS) as pretreatment evaluation for radiofrequency ablation (RFA) of small hepatocellular carcinomas (HCC) (<3cm and 1.5cm)

Materials and Methods: From January 2013 to February 2014, 16 patients having 22 small HCC were evaluated with Sonazoid CEUS prior to RFA. We analyzed our clinical data, radiologic reports, and US images to determine whether the location of candidates on conventional US correspond to that on Sonazoid CEUS. To get complete ablation, RFA was performed only when nodules were identified on planning conventional US or Sonazoid CEUS. We graded the conspicuity of lesion on the following 3 point scale: 1, clearly defined; 2, defined to degree that RFA possible; 3, poorly defined to degree that RFA impossible. The improvement of lesion conspicuity in Sonazoid CEUS compare to conventional US was assessed.

Results: Among 22 small HCCs (<3cm), 20 (90.9%) nodules in Sonazoid CEUS were grade 1 or 2, whereas 15 (77.3%) nodules in conventional US were. 7 (31.8%) nodules showed the Improvement of lesion conspicuity in Sonazoid CEUS. Among 14 very small HCCs ( 1.5cm), 13 (92.8%) nodules in Sonazoid CEUS were grade 1 or 2, whereas 10 (71.4%) nodules in conventional US were. 6 (42.8%) nodules showed the improvement of lesion conspicuity in Sonazoid CEUS.

Conclusion: Sonazoid CEUS is effective to improve lesion conspicuity for RFA of small HCCs, especially more in size of 1.5cm than <3cm.


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P-11 What can CEUS do to breast lesions which are classified BI-RADS®-US 4?

Jun Luo, Chengqin, Chengjidong

Department of Ultrasound, Sichuan Academy of Medical Sciences, Sichuan Provincial People sʹ Hospital

[Background and Objective]Conventional ultrasound plays an important role in detecting breast lesions. But depending on typical BI-RADS®-US, there are so many benign lesions will be classified BI-RADS®-US 4, and all these patients may face to biopsy. Is typical BI-RADS®-US good enough? In our study, we focus exclusively on BI-RADS®-US 4 lesions ,hypothesize that advanced BI-RADS®-US combined with contrast-enhanced ultrasound (CEUS) can be established, and aim to investigate the diagnostic value of CEUS in breast lesions and reduce false-positive biopsies.

[Materials and Methods]The clinical data of 208 breast lesions (118 benigns, 90 malignants) which were classified BI-RADS®-US 4 were additionally examined with CEUS enrolled in this study. After intraveneous (i.v.) injection of a 4.8mL bolus of SonoVue®, lesions were scanned with real-time gray-scale pulse inversion harmonic imaging US for at least 2 minutes at low mechanical index (MI) (0.05 to 0.08). The enhancement appearences such as type, range and patterns of enhancement were observed. Pathological findings (core biopsy or surgical specimen) at the patient’s definitive intervention served as the reference standard. The results were analyzed comparatively between benign and malignant lesions. Biopsy rates, accuracy, sensitivity, specificity, positive and negative predictive values of advanced BI-RADS®-US combined with CEUS were calculated. Furthermore, we analyzed the false-negative and false-positive cases and performed a model calculation to determine how CEUS could affect the proceedings in population screening.

[Results]An advanced BI-RADS®-US gave highly accurate risk estimates for malignant breast lesions as the pretest biopsy rate was 100% compared with the posttest was only 49.52%, which means there were 50.48% of biopsies should be avoided. The accuracy, sensitivity, specificity, positive and negative predictive value of the advanced BI-RADS®-US was 90.38%, 92.78%, 85.96%, 84.91% and 93.33%. Malignant lesions (75/90, 83.33%) were more likely to be quick wash-in and slow wash-out vs. benign group (42/118, 35.59%) (P<0.05), and also with hyperenhancement (malignant 78/90, 86.67% vs. benign 46/118, 38.98%, P<0.05)(Figure 1,2). Amplification enhanced range were much more likely to be seen (64/90, 71.11%) than benign group (16/118, 13.56%) (P<0.05), and most of these benign lesions which showed amplification enhanced range were inflammatory or precancerous lesions. Moreover, there were no significant difference between malignant and benign lesions in direction and distribution of enhancement.

[Conclusions]CEUS yields additional diagnostic information in the evaluation of BI-RADS®-US 4 lesions of the breast. Depending on advanced BI-RADS®-US combined with CEUS, the examiner can identify a low-risk group that can be vigilantly observed with biopsy if any change and may safely reduce the number of false-positive biopsies.

Figure 1 Figure 2


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P-12 Length/Width ratio of ductus venosus in simple screening for fetal congenital heart diseases in the second trimester

Wei-Hsiu Chiu1,2,3), Xiao-Mei Tang4), Cheng-In Hoi1), Shuo-Hui Hung5,6), Ranchou Chen1,6)

1) Department of Biomedical Imaging and Radiological Sciences, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan

2) 1st Clinical Medical College, Jinan University, Guangzhou, China 3) Department of Obstetrics and Gynecology, Chung Shan Hospital, Taipei, Taiwan 4) Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, China 5) School of Medicine, National Yang-Ming University, Taipei, Taiwan 6) Department of Surgery, Taipei City Hospital, Taipei, Taiwan

Objective: Antenatal diagnosis of congenital heart disease (CHD) is still low even though screening was first introduced over 25 years ago. The purpose of our study was to determine the efficacy of a second-trimester prenatal ultrasonographic method of screening for CHD.

Methods: From August 2009 and May 2011, the length and width of the fetal ductus venosus were measured sonographically in 1006 singleton fetuses, and the ratio of length to width was calculated. The efficacies of each fetal measurement and Doppler ultrasonography were determined. The standard fetal echocardiographic evaluations including two dimensional gray-scale imaging, color, and Doppler color flow mapping were performed. The transducer was aligned to the long axis of the fetal trunk to view the ductus venosus in its full length, including the inlet (isthmus) and outlet portions of the vessel. The diameters of the vessel inner wall and mid-point of the ductus venosus were measured using calipers. All scans and fetal measurements were conducted by a registered sonographer with 15 years of perinatal ultrasound screening experience.

Results: Of the 1006 singleton fetuses between 19+0 and 28+6 weeks’ gestation, 36 had CHD. The ductus venosus length/width ratio for the first CHD screening was extremely sensitive 99.10%, with specificity of 88.90% for the cardiac abnormalities included in this study Chromosomal anomalies accompanied CHD in 0.4% (4/1006) of all cases and 11.11% (4/36) of the CHD cases.

Conclusions: The ductus venosus length/width ratio differed significantly between fetuses with CHD and normal fetuses during the second trimester. Careful assessment of the ratio should be a part of the sonographic examination of every fetus. In the case of a small ductus venosus length/width ratio, advanced echocardiography and a karyotype should be performed. The ratio is a helpful tool for detecting CHD abnormalities prenatally in the Chinese population.


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P-13 Feasibilities of drug-loaded microbubbles in intravesical chemotherapy of bladder cancer

Shuo-Hui Hung1,2), Ran-Chou Chen3,4), Tung-Hu Tsai1), Wei-Hsiu Chiu3), Cheng-In Hoi3), Li-Wen Chang1)

1) School of Medicine, National Yang-Ming University, Taipei, Taiwan 2) Department of Surgery, Taipei City Hospital, Taipei, Taiwan 3) Department of Biomedical Imaging and Radiological Sciences, NationalYang-MingUniversity, Taipei, Taiwan 4) Department of Radiology, Taipei City Hospital, Taipei, Taiwan

Conventional intravesical chemotherapy is commonly used in treatment of non-muscle invasive urinary bladdercancer. However, drug would beeliminated by voiding, and difficultly targeted to certain portion of bladder. Ultrasound-triggered drug loaded microbubble disruption is a promising strategy to increase local drug concentration at pathologic site while reducing systemic toxicity. Sufficient ultrasonic energy will disrupt the shells of these carriers and release the enclosed drugs. Simultaneously, sonoporation effect will improve drug diffusion into the interstitial space of therapeutic site. We developed a lipid-coated, drug loaded, nanobubble for diagnosis imaging and targeted drug delivery. The size of nanobubbles was around 270 nm with a polydispersity index (PDI) <0.35. Following insertion of nanobubbles into bladder of Sprague-Dawley rats, contrast enhanced ultrasound were used to monitor the stabilities of nanobubble and access the degree nonabubbles disruption with higher mechanical index ultrasound. A significantly longer half-life of nanobubble was obtained with the intravesical phase when compared with the intravascular circulation. Drug loaded microbubble with ultrasonic cavitation has promising applications in intravesical chemotherapy for bladder cancer.

Documents

P-1 Synthesizing cationic microbubbles for improving ...jabts.umin.jp/jabts32/acuci2014/dl/Abstract_p.pdfwith the concentration of cationic MBs (1-50μL) and the exposure time of US