ICUS Weekly News Monitor 1-29-2016

1.  Journal of Ultrasound in Medicine,  Feb 1, 2016,  Kupffer Imaging by Contrast-Enhanced Sonography With Perfluorobutane Microbubbles Is Associated With Outcomes After Radiofrequency Ablation of Hepatocellular Carcinoma      Authors: Junya Nuta, MD, et al
 
2.  Nanowerk News,  Jan 28,2016,  Trapping microbubbles with lasers and sound
 
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Journal of Ultrasound in Medicine
Published January 18, 2016, doi: 10.7863/ultra.15.04067
JUM February 1, 2016   vol. 35  no. 2  359-371
Feb 1, 2016
 
Kupffer Imaging by Contrast-Enhanced Sonography With Perfluorobutane Microbubbles Is Associated With Outcomes After Radiofrequency Ablation of Hepatocellular Carcinoma
 
Authors: Junya Nuta, MD, Hideyuki Tamai, MD, PhD⇑, Yoshiyuki Mori, MD, Naoki Shingaki, MD, Shuya Maeshima, MD,  Ryo Shimizu, MD, Yoshimasa Maeda, MD, Kosaku Moribata, MD, PhD,
Toru Niwa, MD, PhD, Hisanobu Deguchi, MD,  Izumi Inoue, MD, PhD, Takao Maekita, MD, PhD,
Mikitaka Iguchi, MD, PhD, Jun Kato, MD, PhD and Masao Ichinose, MD, PhD
 
+ Author Affiliations
 
Second Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan.
Address correspondence to Hideyuki Tamai, MD, PhD, Second Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-0012, Japan. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
 
Abstract
 
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.
 
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Nanowerk News
Jan 28,2016
 
Trapping microbubbles with lasers and sound
 
(Nanowerk News) The National Physical Laboratory (NPL) has worked with University College London (UCL) and the University of Oxford to develop an innovative system that can trap microbubbles. This enables scientists to study the bubbles' properties and develop safer, more effective medical products.
 
Microbubbles are gas bubbles that are smaller than 1 mm in size - their radius is typically between 1 and 10 microns for medical applications. In the past 10 years, the use of microbubbles to enhance contrast in ultrasound images has become an everyday practice in hospitals in UK and across the world. Microbubbles now sit at the forefront of techniques used for the diagnosis of heart diseases and certain types of cancer.
 
trapped bubbles
Video frames of acoustically trapped bubbles and one optically trapped bubble (centre in all images) which is manipulated away from the cloud
 
New technological advances, and recent successes in treatment have shown that the addition of certain molecules to the shell of these bubbles could make them ideal vehicles for targeted medicine delivery and microsurgery.
As the potential applications increase, it becomes more important to characterise how microbubbles interact with sound and how different manufacturing techniques impact on their performance. Information about the microbubble properties can be used to engineer bubbles for specific medical uses, and in a more cost-effective way.
 
Scientists from NPL have worked with UCL and the University of Oxford to develop a controlled setting in which to study microbubbles. The unique device, which was designed and constructed at NPL, traps the microbubbles using optical tweezers in combination with acoustic tweezers, which control the movement of objects using sound waves.
 
While these two techniques are commonly used for solid particles, they both present challenges when used with bubbles. Optical tweezers, for instance, are often used to trap and study biological samples using highly-focused laser beams to hold and move items. However, objects with a low refractive index, such as microbubbles, are difficult to optically trap due to strong repulsive forces experienced in proximity to high intensity light.
 
Bubbles also present a peculiar response to acoustical tweezing, behaving in different ways depending on the selected manipulation frequency. If the acoustic field is higher than the bubbles natural frequency they will move to where the field is strongest in pressure, but if the field is lower than the natural frequency the bubbles will collect at the weakest point.
 
This method will allow researchers to perform characterization at the single bubble level and support the development of medical microbubbles. Fully characterised bubbles may even act as stand-alone sensors, for stratified medicine purposes.
 
Source: National Physical Laboratory

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