Zion Tsz Ho Tse

The case for MR-compatible robotics: a review of the state of the art

The numerous imaging capabilities of magnetic resonance imaging (MRI) coupled with its lack of ionizing radiation has made it a desirable modality for real‐time guidance of interventional procedures. The combination of these abilities with the advantages granted by robotic systems to perform accurate and precise positioning of tools has driven the recent development of MR‐compatible interventional and assistive devices.

Ebola and the social media

In October 2014, during heightened news coverage about cases of Ebola in the USA, anecdotal observations suggested that many Americans were anxious about Ebola. Given the negligible risk of infection, their anxiety was arguably driven by perceived rather than actual risk. Exaggeration or reassurance from the media can infl ame or subdue people’s perceived risk of Ebola infection. Fear can also be acquired by observation of other people’s experiences, as expressed on social media. Thus, social media amplifi ed fear about the imported Ebola case. As discussed in The Lancet Editorial (Nov 8, 2014), Twitter traffi c shows an imbalance across the digital divide; there were more tweets about Ebola in the USA, where transmission was contained, than in Guinea, Liberia, and Sierra Leone, where there was and remains a continuing epidemic. Despite the risk to most Americans being negligible, many people expressed anxiety. The figure shows how worldwide traffi c on Twitter and Google about Ebola increased as news spread about the fi rst US case and how they compare with influenza (flu)-related searches and tweets. Similar peaks were observed when other news about Ebola was released. In a random sample of tweets, we observed that the frequency of Ebola-related tweets associated with negative emotions, anxiety, anger, swearing, and death, as well as discrepant thinking (eg, shouldn’t), were higher than those associated with infl uenza (see fi gure in appendix). Twitter data can provide public health practitioners with a quantitative indicator of anxiety, anger, or negative emotions in the general public where Twitter penetration is high. This indicator could help to alleviate anxiety and correctly communicate the risk associated with Ebola.

Chinese social media reaction to the MERS-CoV and avian influenza A(H7N9) outbreaks

BackgroundAs internet and social media use have skyrocketed, epidemiologists have begun to use online data such as Google query data and Twitter trends to track the activity levels of influenza and other infectious diseases. In China, Weibo is an extremely popular microblogging site that is equivalent to Twitter. Capitalizing on the wealth of public opinion data contained in posts on Weibo, this study used Weibo as a measure of the Chinese people’s reactions to two different outbreaks: the 2012 Middle East Respiratory Syndrome Coronavirus (MERS-CoV) outbreak, and the 2013 outbreak of human infection of avian influenza A(H7N9) in China.MethodsKeyword searches were performed in Weibo data collected by The University of Hong Kong’s Weiboscope project. Baseline values were determined for each keyword and reaction values per million posts in the days after outbreak information was released to the public.ResultsThe results show that the Chinese people reacted significantly to both outbreaks online, where their social media reaction was two orders of magnitude stronger to the H7N9 influenza outbreak that happened in China than the MERS-CoV outbreak that was far away from China.ConclusionsThese results demonstrate that social media could be a useful measure of public awareness and reaction to disease outbreak information released by health authorities.

Advances in Haptics, Tactile Sensing, and Manipulation for Robot-Assisted Minimally Invasive Surgery, Noninvasive Surgery, and Diagnosis

The developments of medical practices and medical technologies have always progressed concurrently. The relatively recent developments in endoscopic technologies have allowed the realization of the “minimally invasive” form of surgeries. The advancements in robotics facilitate precise surgeries that are often integrated with medical image guidance capability. This in turn has driven the further development of technology to compensate for the unique complexities engendered by this new format and to improve the performance and broaden the scope of the procedures that can be performed. Medical robotics has been a central component of this development due to the highly suitable characteristics that a robotic system can purport, including highly optimizable mechanical conformation and the ability to program assistive functions in medical robots for surgeons to perform safe and accurate minimally invasive surgeries. In addition, combining the robot-assisted interventions with touch-sensing and medical imaging technologies can greatly improve the available information and thus help to ensure that minimally invasive surgeries continue to gain popularity and stay at the focus of modern medical technology development. This paper presents a state-of-the-art review of robotic systems for minimally invasive and noninvasive surgeries, precise surgeries, diagnoses, and their corresponding technologies.

Magnetic resonance elastography: a general overview of its current and future applications in brain imaging

Magnetic resonance elastography (MRE) has been developed over the last few years as a non-invasive means of evaluating the elasticity of biological tissues. The presence of the skull has always prevented semeiotic palpation of the brain, but MRE now offers the possibility of “palpating by imaging” in order to detect brain consistency under physiological and pathological conditions. The aim of this article is to review the current state-of-the-art of MRE imaging and discuss its possible future diagnostic applications in neuroscience.

Magnetic resonance elastography hardware design: A survey:

Abstract Magnetic resonance elastography (MRE) is an emerging technique capable of measuring the shear modulus of tissue. A suspected tumour can be identified by comparing its properties with those of tissues surrounding it; this can be achieved even in deep-lying areas as long as mechanical excitation is possible. This would allow non-invasive methods for cancer-related diagnosis in areas not accessible with conventional palpation. An actuating mechanism is required to generate the necessary tissue displacements directly on the patient in the scanner and three different approaches, in terms of actuator action and position, exist to derive stiffness measurements. However, the magnetic resonance (MR) environment places considerable constraints on the design of such devices, such as the possibility of mutual interference between electrical components, the scanner field, and radio frequency pulses, and the physical space restrictions of the scanner bore. This paper presents a review of the current solutions that have been developed for MRE devices giving particular consideration to the design criteria including the required vibration frequency and amplitude in different applications, the issue of MR compatibility, actuation principles, design complexity, and scanner synchronization issues. The future challenges in this field are also described.

System for 3-D Real-Time Tracking of MRI-Compatible Devices by Image Processing

Real-time processing of MRIs is reported as a method of 3D tracking of mechanical devices within the field of view using passive microcoil fiducials. The specific implementation described makes use of two scan planes for full 3D tracking of a 5-DOF manipulator arm used for prostate biopsy under image guidance. Real-time tracking was observed with a maximum update rate of 0.42 frames per second for a maximum probe velocity of 10 mm/s. The localization of fiducials had a mean error of 0.36 (plusmn0.17) mm (p < 0.02), leading to a mean error in the needle tip position of 2.6 (plusmn0.3) mm (p < 0.05).

How people react to Zika virus outbreaks on Twitter? A computational content analysis

Zika-related Twitter incidence peaked after the World Health Organization declared an emergency. Five themes were identified from Zika-related Twitter content: (1) societal impact of the outbreak; (2) government, public and private sector, and general public responses to the outbreak; (3) pregnancy and microcephaly: negative health consequences related to pregnant women and babies; (4) transmission routes; and (5) case reports. User-generated contents sites were preferred direct information channels rather than those of the government authorities.

Magic Angle–Enhanced MRI of Fibrous Microstructures in Sclera and Cornea With and Without Intraocular Pressure Loading

PURPOSE The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle-enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. METHODS Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. RESULTS At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. CONCLUSIONS Magic angle-enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell.

Prospective motion correction using tracking coils

Intracavity imaging coils provide higher signal‐to‐noise than surface coils and have the potential to provide higher spatial resolution in shorter acquisition times. However, images from these coils suffer from physiologically induced motion artifacts, as both the anatomy and the coils move during image acquisition. We developed prospective motion‐correction techniques for intracavity imaging using an array of tracking coils. The system had <50 ms latency between tracking and imaging, so that the images from the intracavity coil were acquired in a frame of reference defined by the tracking array rather than by the systems gradient coils. Two‐dimensional gradient‐recalled and three‐dimensional electrocardiogram‐gated inversion‐recovery‐fast‐gradient‐echo sequences were tested with prospective motion correction using ex vivo hearts placed on a moving platform simulating both respiratory and cardiac motion. Human abdominal tests were subsequently conducted. The tracking array provided a positional accuracy of 0.7 ± 0.5 mm, 0.6 ± 0.4 mm, and 0.1 ± 0.1 mm along the X, Y, and Z directions at a rate of 20 frames‐per‐second. The ex vivo and human experiments showed significant image quality improvements for both in‐plane and through‐plane motion correction, which although not performed in intracavity imaging, demonstrates the feasibility of implementing such a motion‐correction system in a future design of combined tracking and intracavity coil. Magn Reson Med, 2013.