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Chủ Nhật, 7 tháng 12, 2014

O-mode ULTRASOUND in DEVELOPMENT



CHICAGO — The new O-mode form of ultrasound, which improves visualization behind structures and eliminates the need for beam formation, also weighs and costs less than conventional ultrasound, according to researchers presenting here at the Radiological Society of North America 100th Annual Meeting.
"We were quite impressed that, for the little bit of work that we did, we got such images," said Richard Barr, MD, from the Northeast Ohio Medical University in Youngstown. "The technology is actually not extremely complex," he explained, and said he expects that the small hand-held O-mode device will be available next year.
Dr. Barr presented a proof-of-concept study that confirmed that O-mode imaging is possible in a clinical setting.
The beam focuser required for traditional B-mode ultrasound imaging is considered to be important, but can lead to many of the limitations and artifacts seen in conventional scans. In contrast, the O-mode technique does not require a beam focuser.
The novel technique mimics a "single transducer lateral motion" along a known trajectory. This allows the Doppler effect to be evoked artificially from the "moving" transducer.
The result is an echo in different radiofrequency shifts that comes from the different scatterers located at the same depth but at different lateral positions, Dr. Barr explained. The technique makes it possible to visualize a Doppler shift between the Z particles.
O-mode provides constant lateral resolution that is independent of depth of penetration. It therefore significantly decreases the shadowing from small pockets of gas, allowing for the use of new imaging windows.
It also allows for exact lateral localization by exchanging the traditional ultrasound focusing procedure along the line of sight with signal processing of frequency-modulated signals that come from each depth.
Proof of Concept
To test the effectiveness of the O-mode method, Dr. Barr and his team used the technique to scan various organs of 10 patients.
When the images, which received very little post-processing, were reviewed by a board-certified radiologist, all were deemed to visualize deep structures at least as well as conventional B-mode ultrasound.
In addition, O-mode imaging can be performed in real time at 30 to 40 frames per minute, a rate typical of that seen with other systems, Dr. Barr pointed out.
"That's interesting," said session moderator Jason Stafford, PhD, from the University of Texas MD Anderson Cancer Center in Houston. He told Medscape Medical News that he is eager to read more about the technique.
The next step will be to "implement a small device that will be for the market," said Mati Shirizly, PhD, chief executive officer of Orcasonix, the company that will be manufacturing the O-mode ultrasound. The small device will likely retail for approximately $5000.
"Eventually, we will want to put this technology into a high-end system," Dr. Shirizly told Medscape Medical News. He said he thinks the technique will be particularly useful for imaging the hearts of obese patients.
However, during his presentation, Dr. Barr acknowledged that the O-mode technique still requires improved contrast resolution and improved image processing. Because the O-mode does not yet include image processing, it is difficult to truly compare it to conventional ultrasounds. "At this point, it really is hard to do a comparison of apples to apples. It really is apples to oranges," he said.
This study received funding by Orcasonix, the company that will manufacture the O-mode ultrasound. Dr. Barr is a consultant at Siemens AG. Dr. Stafford has disclosed no relevant financial relationships. Dr. Shirizly is a shareholder at Orcasonix.
Radiological Society of North America (RSNA) 100th Annual Meeting: Abstract SSA21-09. Presented November 30, 2014.

Orcasonix Unveils Innovative Ultrasound Technology Built on Cephasonics cQuest Family of Ultrasound Systems

Visit Cephasonics at RSNA 2013 in Hall B, Booth 8522
Monday, December 2, 2013 - 06:00
Chicago, December 2, 2013—Cephasonics, a technology-innovation leader with a game-changing embedded-ultrasound platform, and Orcasonix, an innovative ultrasound company specializing in imaging systems with depth-independent resolution, today disclosed details of the Cephasonics design-in. Orcasonix used the Cephasonics cQuest Cicada™ platform to develop its first prototype imaging system, the Orca™-1, and plans to commercialize the system in 2014 and go to volume production with the just announced cQuest Dragonfly™ system. Orcasonix will be showcasing its new technology in Cephasonics’ booth at RSNA 2013 held here in Chicago from December 1-6.  Visitors can also see Cephasonics’ latest technology, including Dragonfly.
According to Mati Shirizly, CEO of Orcasonix, “Cephasonics’ unique business model and flexible cQuest Ultrasound™ hardware/software architecture provided us with a fast way to prove our technology, develop a prototype, and conduct initial clinical trials.” He said that his company’s innovative imaging techniques will dramatically improve the scanning of challenging patients, including general abdominal imaging of obese, overweight patients.
“The Orcasonix team achieved a major breakthrough in ultrasound imaging and we are pleased to partner with them both in demonstrating the unique capabilities of their depth-independent resolution imaging system and supporting their production ramp with our solutions,” said Richard Tobias, CEO of Cephasonics.
Orcasonix developed a new ultrasound imaging system with depth-independent resolution that uses a novel patented approach of generating CT-like images from sound echoes. The technology enables an extremely low cost hardware implementation with a virtually unlimited number of channels at a fraction of the cost of current systems. Signal and image processing is extremely efficient, thus significantly reducing the cost of the ultrasound system’s computer sub-system. The Orca-1 will be the first in a planned family of high-quality, cost-efficient imaging systems.
About Cephasonics
A technology-innovation leader with a game-changing embedded-ultrasound platform, Cephasonics provides a complete range of cQuest™-based technology, systems and components that increase the performance, lower the power and accelerate time-to- market of ultrasound devices. The company’s cQuest Ultrasound API™ software is the catalyst for customer innovations that are spurring a revolution in ultrasound from image-guided procedures to ultrasound as an appliance. Launched with a management buyout in March 2012 and headquartered in Santa Clara, Calif., Cephasonics’ technology, including its AutoFocus™ beamforming technology, has won multiple industry awards for innovation. Additional information about Cephasonics can be found at www.cephasonics.com.
About Orcasonix
An innovative ultrasound imaging company that has developed a new ultrasound-imaging platform with depth-independent resolution, Orcasonix was established in 2011 and is based in Netanya, Israel. Its first product has started clinical trials and others are in early stages of development. Additional information about Orcasonix can be found at www.orcasonix.com
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cQuest, cQuest Ultrasound, cQuest Ultrasound API, cQuest Cicada, cQuest Dragonfly, and AutoFocus are trademarks of Cephasonics.
Orca-1 is a trademark of Orcasonix.

Thứ Bảy, 6 tháng 12, 2014

ARFI DỰ ĐOÁN GIAI ĐOẠN XƠ HÓA GAN Ở GAN NHIỄM MỠ KHÔNG DO RƯỢU [NAFLD]

ĐÁNH GIÁ VAI TRÒ CỦA KỸ THUẬT GHI HÌNH XUNG LỰC BỨC XẠ ÂM (ARFI)
TRONG DỰ ĐOÁN GIAI ĐOẠN XƠ HÓA GAN TRÊN BỆNH NHÂN
BỊ VIÊM GAN NHIỄM MỠ KHÔNG DO RƯỢU

              Trần Thị Khánh Tường 1, Hoàng Trọng Thảng 2, Võ Thị Xuân Hạnh3
                              1, 3 Trường Đại học Y khoa Phạm Ngọc Thạch
 2 Trường Đại học Y Dược Huế

TÓM TẮT

Tổng quan và mục tiêu :  Xung lực bức xạ âm (ARFI) một kỹ thuật mới không xâm lấn, đơn giản dùng để đánh giá các giai đoạn xơ hóa gan trong bệnh gan mạn. Một số nghiên cứu trước đây cho thấy rằng ARFI là phương tiện đầy hứa hẹn trong đánh giá xơ hóa gan ở bệnh nhân bị bệnh gan nhiễm mỡ không do rượu (NAFLD). Nghiên cứu này nhằm mục đích xác định giá trị chẩn đoán của ARFI trong dự đoán giai đoạn xơ hóa ở những bệnh nhân bị viêm gan nhiễm mỡ không do rượu (NASH).
Đối tượng và phương pháp nghiên cứu : Nghiên cứu được thực hiện trên 51 bệnh nhân bị NASH. Tất cả bệnh nhân đều được sinh thiết gan để đánh giá xơ hóa ganthực hiện kỹ thuật ARFI. Các giá trị ngưỡng được xác định bằng cách phân tích đường cong ROC.
Kết quả : Xơ hóa gan xác định bằng giải phẫu bệnh được đánh giá bằng thang điểm Metavir, F0: 8 trường hợp, F1: 29 trường hợp, F2: 10 trường hợp, F3: 4 trường hợp. ARFItương quan khá chặt với mức độ xơ hóa (Spearman rho: 0.44, p <0.05). Diện tích dưới đường cong ROC (AUROC) 0.75 (khoảng tin cậy 95%: 0.60-0.90) đối với F20.78 (0.53-0.99) đối với F3. Giá trị ngưỡng của vận tốc sóng biến dạng (SWV) như sau: 1,29 m/s cho ≥ F2 (độ nhạy 64.3%, độ đặc hiệu 83.8%, PPV 60% và NPV 86.1%); 1,38 m/s cho F3 (độ nhạy 75.00%, độ đặc hiệu 89.4%, PPV 57.5% và NPV 97.7%).

Kết luận: SWV của ARFI tương quan với mức độ của xơ hóa gan. Kỹ thuật ARFI có độ chính xác khá tốt, độ chuyên và NPV cao trong đánh giá xơ hóa gan đáng kể và xơ hóa nặng  ở những bệnh nhân bị NASH. Kỹ thuật này nên thực hiện thường qui cho các bệnh nhân bị NASH để loại trừ xơ hóa gan đáng kể và xơ hóa gan nặng.

Từ khóa: xơ hóa gan, độ cứng của gan, bệnh gan nhiễm mỡ không do rượu (NAFLD), viêm gan nhiễm mỡ không do rượu (NASH), kỹ thuật xung lực bức xạ âm (ARFI)


ABSTRACT

ASSESSING THE ROLE OF ACOUSTIC RADIATION FORCE IMPULSE IMAGING FOR PREDICTION OF STAGING OF LIVER FIBROSIS
IN PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS


Background / Objectives: Acoustic radiation force impulse (ARFI) is a novel non-invasive technology for the assessment of stages of liver fibrosis in chronic hepatic disease. Some studies previously reported that ARFI is a promising method for assessing liver fibrosis in patients with NAFLD/NASH. This study aimed to validate the diagnostic usefulness of ARFI for prediction of staging of liver fibrosis in patients with NASH.
Patients and Methods: The study was carried out on 51 patients with NASH. All of patients underwent a liver biopsy for histological assessment of liver fibrosis and ARFI elastography. Cut-off values were determined using receiver-operating characteristic (ROC) curves.
Results: Histological liver fibrosis was evaluated by Metavir scoring; F0: 8 cases, F1: 29 cases, F2: 10 cases and F3: 4 cases. ARFI quantification correlated significantly with the fibrosis stage (Spearman rho: 0.44, p <0.05). The areas under the ROC curves (AUROC) were  0.75 (95% confidence intervals: 0.60-0.90) for F2 and 0.78 (0.53-0.99) for F3. The cut-off values of the shear wave velocity (SWV) were as follows: ≥1.29 m/s for F2 (sensitivity 64.3%, specificity 83.8%, PPV 60% and NPV 86.1%), 1.38 m/s for F3 (sensitivity 75%, specificity 89.4%, PPV 57.5%, NPV 97.7%).
Conclusions: Increasing ARFI velocities correlate with high degree of liver fibrosis. ARFI has quite good accuracy and high specificity, NPV for prediction of significant and advanced fibrosis in patients with NASH. The method should be employed routinely in the workup of patients with NASH to exclude the presence of significant and advanced liver fibrosis.

Key words: liver fibrosis, liver stiffness, non-alcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), acoustic radiation force impulse imaging (ARFI).