Imperial College London

Prof Guang-Zhong Yang

Faculty of EngineeringDepartment of Computing

Director, The Hamlyn Centre
 
 
 
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Contact

 

+44 (0)20 7594 1499g.z.yang Website

 
 
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Assistant

 

Miss Raphaele Raupp +44 (0)20 7594 1499

 
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Location

 

B411-412Bessemer BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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1009 results found

Anastasova S, Kassanos P, Yang G-Z, 2018, Multi-parametric rigid and flexible, low-cost, disposable sensing platforms for biomedical applications, BIOSENSORS & BIOELECTRONICS, Vol: 102, Pages: 668-675, ISSN: 0956-5663

JOURNAL ARTICLE

Anastasova S, Kassanos P, Yang GZ, 2018, Electrochemical sensor designs for biomedical implants, Implantable Sensors and Systems: From Theory to Practice, Pages: 19-98, ISBN: 9783319697482

© Springer International Publishing AG 2018. The need to record directly the sensing target of interest in the vicinity of where a physiological and clinically relevant event takes place, rather than indirectly or through surrogate measures, has led to the need for implantable monitoring devices. In addition to ensuring the sensitivity and specificity of sensor responses, issues related to sensor fouling, drift, biocompatibility, and hermeticity of the packaging are important considerations. This chapter examines the current state of the art of sensing techniques, focusing on electrochemical methods (potentiometry, amperometry, and voltammetry), due to their simplicity in design and fabrication [1], as well as low-power operation.

BOOK CHAPTER

Berthelot M, Yang G-Z, Lo B, 2018, A Self-Calibrated Tissue Viability Sensor for Free Flap Monitoring, IEEE JOURNAL OF BIOMEDICAL AND HEALTH INFORMATICS, Vol: 22, Pages: 5-14, ISSN: 2168-2194

JOURNAL ARTICLE

Berthet-Rayne P, Gras G, Leibrandt K, Wisanuvej P, Schmitz A, Seneci CA, Yang G-Zet al., 2018, The i2Snake Robotic Platform for Endoscopic Surgery., Ann Biomed Eng

Endoscopic procedures have transformed minimally invasive surgery as they allow the examination and intervention on a patient's anatomy through natural orifices, without the need for external incisions. However, the complexity of anatomical pathways and the limited dexterity of existing instruments, limit such procedures mainly to diagnosis and biopsies. This paper proposes a new robotic platform: the Intuitive imaging sensing navigated and kinematically enhanced ([Formula: see text]) robot that aims to improve the field of endoscopic surgery. The proposed robotic platform includes a snake-like robotic endoscope equipped with a camera, a light-source and two robotic instruments, supported with a robotic arm for global positioning and for insertion of the [Formula: see text] and a master interface for master-slave teleoperation. The proposed robotic platform design focuses on ergonomics and intuitive control. The control workflow was first validated in simulation and then implemented on the robotic platform. The results are consistent with the simulation and show the clear clinical potential of the system. Limitations such as tendon backlash and elongation over time will be further investigated by means of combined hardware and software solutions. In conclusion, the proposed system contributes to the field of endoscopic surgical robots and could allow to perform more complex endoscopic surgical procedures while reducing patient trauma and recovery time.

JOURNAL ARTICLE

Chi W, Liu J, Rafii-Tari H, Riga C, Bicknell C, Yang G-Zet al., 2018, Learning-based endovascular navigation through the use of non-rigid registration for collaborative robotic catheterization, INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY, Vol: 13, Pages: 855-864, ISSN: 1861-6410

JOURNAL ARTICLE

Constantinescu MA, Lee S-L, Ernst S, Hemakom A, Mandic D, Yang G-Zet al., 2018, Probabilistic guidance for catheter tip motion in cardiac ablation procedures., Med Image Anal, Vol: 47, Pages: 1-14

Radiofrequency catheter ablation is one of the commonly available therapeutic methods for patients suffering from cardiac arrhythmias. The prerequisite of successful ablation is sufficient energy delivery at the target site. However, cardiac and respiratory motion, coupled with endocardial irregularities, can cause catheter drift and dispersion of the radiofrequency energy, thus prolonging procedure time, damaging adjacent tissue, and leading to electrical reconnection of temporarily ablated regions. Therefore, positional accuracy and stability of the catheter tip during energy delivery is of great importance for the outcome of the procedure. This paper presents an analytical scheme for assessing catheter tip stability, whereby a sequence of catheter tip motion recorded at sparse locations on the endocardium is decomposed. The spatial sliding component along the endocardial wall is extracted from the recording and maximal slippage and its associated probability are computed at each mapping point. Finally, a global map is generated, allowing the assessment of potential areas that are compromised by tip slippage. The proposed framework was applied to 40 retrospective studies of congenital heart disease patients and further validated on phantom data and simulations. The results show a good correlation with other intraoperative factors, such as catheter tip contact force amplitude and orientation, and with clinically documented anatomical areas of high catheter tip instability.

JOURNAL ARTICLE

Deligianni F, Wong C, Lo B, Yang G-Zet al., 2018, A fusion framework to estimate plantar ground force distributions and ankle dynamics, INFORMATION FUSION, Vol: 41, Pages: 255-263, ISSN: 1566-2535

JOURNAL ARTICLE

Fabelo H, Ortega S, Lazcano R, Madronal D, Callico GM, Juarez E, Salvador R, Bulters D, Bulstrode H, Szolna A, Pineiro JF, Sosa C, O'Shanahan AJ, Bisshopp S, Hernandez M, Morera J, Ravi D, Kiran BR, Vega A, Baez-Quevedo A, Yang G-Z, Stanciulescu B, Sarmiento Ret al., 2018, An Intraoperative Visualization System Using Hyperspectral Imaging to Aid in Brain Tumor Delineation, SENSORS, Vol: 18, ISSN: 1424-8220

JOURNAL ARTICLE

Fabelo H, Ortega S, Ravi D, Kiran BR, Sosa C, Bulters D, Callico GM, Bulstrode H, Szolna A, Pineiro JF, Kabwama S, Madronal D, Lazcano R, J-O'Shanahan A, Bisshopp S, Hernandez M, Baez A, Yang G-Z, Stanciulescu B, Salvador R, Juarez E, Sarmiento Ret al., 2018, Spatio-spectral classification of hyperspectral images for brain cancer detection during surgical operations, PLOS ONE, Vol: 13, ISSN: 1932-6203

JOURNAL ARTICLE

Fujii K, Gras G, Salerno A, Yang G-Zet al., 2018, Gaze gesture based human robot interaction for laparoscopic surgery, MEDICAL IMAGE ANALYSIS, Vol: 44, Pages: 196-214, ISSN: 1361-8415

JOURNAL ARTICLE

Giataganas P, Hughes M, Payne C, Wisanuvej P, Temelkuran B, Yang GZet al., 2018, Intraoperative robotic-assisted large-area high-speed microscopic imaging and intervention, IEEE Transactions on Biomedical Engineering, ISSN: 0018-9294

IEEE Objective: Probe-based confocal endomicroscopy is an emerging high-magnification optical imaging technique that provides in-vivo and in-situ cellular-level imaging for real-time assessment of tissue pathology. Endomicroscopy could potentially be used for intraoperative surgical guidance, but it is challenging to assess a surgical site using individual microscopic images due to the limited field-of-view and difficulties associated with manually manipulating the probe. Methods: In this paper, a novel robotic device for large-area endomicroscopy imaging is proposed, demonstrating a rapid, but highly accurate, scanning mechanism with image-based motion control which is able to generate histology-like endomicroscopy mosaics. The device also includes, for the first time in robotic-assisted endomicroscopy, the capability to ablate tissue without the need for an additional tool. Results: The device achieves pre-programmed trajectories with positioning accuracy of less than 30um, the image-based approach demonstrated that it can suppress random motion disturbances up to 1.25mm/s. Mosaics are presented from a range of ex-vivo human and animal tissues, over areas of more than 3mm<formula><tex>$^2$</tex></formula>, scanned in approximate 10s. Conclusion: This work demonstrates the potential of the proposed instrument to generate large-area, high-resolution microscopic images for intraoperative tissue identification and margin assessment. Significance: This approach presents an important alternative to current histology techniques, significantly reducing the tissue assessment time, while simultaneously providing the capability to mark and ablate suspicious areas intraoperatively.

JOURNAL ARTICLE

Gil B, Ip H, Yang GZ, 2018, Power harvesting and data exchange links, Implantable Sensors and Systems: From Theory to Practice, Pages: 507-593, ISBN: 9783319697482

© Springer International Publishing AG 2018. For data exchange of implantable devices, wireless links are unavoidable except for the case when an indwelling catheter or probe is allowed to establish either a direct or close contact with the implantable sensor. Light transmission via optical fibers can offer a solution to accomplish data exchange. However, without a conductive path to the outside world, the environment found inside the human body for the propagation of electromagnetic radiation poses new challenges. The problem of data exchange in implantable sensors only encounters a contender of the same level when sensor powering comes to play, at least for active sensing systems. It is therefore possible to retrieve data from passive sensors with no need for DC powering, as will be discussed later in this chapter. Nevertheless, the vast majority of implantable sensors are still actively powered and the subject of power consumption cannot be overlooked. Low power consumption is of paramount importance in implantables to ensure long-term function of the sensor and patient safety.

BOOK CHAPTER

Gil B, Ip H, Yang GZ, 2018, Wireless datapaths and security, Implantable Sensors and Systems: From Theory to Practice, Pages: 595-635, ISBN: 9783319697482

© Springer International Publishing AG 2018. For Implantable Medical Devices (IMD), we have discussed in the previous chapters the technical challenges related to biocompatible materials, flexible fabrication processes, system-on-chip design, low-power operation, and packaging. Increasingly advanced computing capabilities found in IMDs and networking technologies can further broaden the applications and enhance the functions of these devices. However, they can only make a real impact on healthcare when a high level of security is incorporated in these devices. This chapter discusses the relationship between different components of an IMD security system under intrinsic resource constraints. A qualitative overview of the strategies commonly used to provide a secure implant system is provided and the chapter covers the design considerations of lightweight and no-hardware-intensive algorithms for implants.

BOOK CHAPTER

Gowers SAN, Hamaoui K, Cunnea P, Anastasova S, Curto VF, Vadgama P, Yang G-Z, Papalois V, Drakakis EM, Fotopoulou C, Weber SG, Boutelle MGet al., 2018, High temporal resolution delayed analysis of clinical microdialysate streams, ANALYST, Vol: 143, Pages: 715-724, ISSN: 0003-2654

JOURNAL ARTICLE

Huang B, Ye M, Hu Y, Vandini A, Lee S-L, Yang G-Zet al., 2018, A Multirobot Cooperation Framework for Sewing Personalized Stent Grafts, IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS, Vol: 14, Pages: 1776-1785, ISSN: 1551-3203

JOURNAL ARTICLE

Kassanos P, Anastasova S, Chen CM, Yang GZet al., 2018, Sensor embodiment and flexible electronics, Implantable Sensors and Systems: From Theory to Practice, Pages: 197-279, ISBN: 9783319697482

© Springer International Publishing AG 2018. Sensor embodiment and packaging are particularly important for implantable systems. One key element is the development of flexible electronics. Traditional electronics, based on rigid silicon technologies, is associated with a number of intrinsic disadvantages. The inherent brittleness of inorganic semiconductors and stiffness of Si wafer-based devices represent a major issue when interfaced with tissues. This is because our internal organs are complex and they have innate responses to reject foreign bodies. Furthermore, tissues are soft, and they undergo constant motion and deformation. In this chapter, we will discuss current progress in flexible printed circuit board (FPC/FPCB) technologies and provide a review of new fabrication techniques and materials for making soft devices and interconnects suitable for implantable applications. Issues related to geometrical designs for mechanically resilient flexible devices, hermetic packaging, biocompatibility and encapsulation are addressed.

BOOK CHAPTER

Kassanos P, Anastasova S, Yang GZ, 2018, Electrical and physical sensors for biomedical implants, Implantable Sensors and Systems: From Theory to Practice, Pages: 99-195, ISBN: 9783319697482

© Springer International Publishing AG 2018. In addition to the electrochemical sensors discussed in Chap. 2, a range of other sensing modalities are also important for biomedical and implantable applications. The frequency-dependent electrical properties of tissues are essential for assessing various physiological parameters. This, for example, can be quantified via electrical bioimpedance measurements, which can be combined and corroborated with electrochemical sensors. The human body is a dynamic system in constant motion; therefore, sensors for the measurement of physical properties such as strain and pressure are also important. Sensors for these applications rely on the measurement of resistance, capacitance, and sometimes inductance, and these will also be discussed in this chapter for completeness. Temperature is an important health marker for various applications, and consequently the current state of the art in temperature sensors is also discussed, in terms of both monolithic integration and discrete sensor solutions. Monitoring of the electrical response of the nervous system and the delivery of stimuli represent an important family of applications for neuroscience research and neuroprosthetic devices. These will be addressed in this chapter, along with various application scenarios. Other aspects to be discussed include sensor metrics, such as sensitivity, limit of detection, stability, linear range, selectivity, and specificity.

BOOK CHAPTER

Kassanos P, Ip H, Yang GZ, 2018, Ultra-low power application-specific integrated circuits for sensing, Implantable Sensors and Systems: From Theory to Practice, Pages: 281-437, ISBN: 9783319697482

© Springer International Publishing AG 2018. In the quest for ever-reducing system size and increased integration and functionality, application-specific integrated circuit (ASIC) technology plays a pivotal role in modern implants, where custom circuits designed at transistor and device levels are replacing off-the-shelf commercial chips and bulky benchtop systems. Recently, commercial system-on-chip (SoC) devices encompassing digital microcontrollers, radio, and analog-digital converters, as well as reconfigurable amplifier circuits, are widely available. Despite this, further development of ASIC-specific implantable systems is required, particularly in the area of multi-channel array sensor interfaces, ultra-low power data acquisition, and circuits that work with specialized micro-sensors for implants. ASICs designed to focus on a particular application have given designers the freedom to optimize power consumption for a set task, unlike general-purpose SoCs that have to cater for a wide range of applications and hence typically consume more power. In this chapter, we begin with a survey on the latest development of ASICs and related integrated systems from literature. This is followed by an overview of technological trends in integrated circuit/sensor fabrication and fusion. The rest of the chapter focuses on a number of engineering aspects related to ultra-low power ASIC circuits appropriate for implantable sensors and sensor front-ends, covering bioimpedance, neural and electrochemical sensor measurement circuits, as well as low-power analog-to-digital converter design and architectures.

BOOK CHAPTER

Kwasnicki RM, Cross GW, Geoghegan L, Zhang Z, Reilly P, Darzi A, Yang GZ, Emery Ret al., 2018, A lightweight sensing platform for monitoring sleep quality and posture: a simulated validation study, EUROPEAN JOURNAL OF MEDICAL RESEARCH, Vol: 23, ISSN: 0949-2321

JOURNAL ARTICLE

Li Y, Charalampaki P, Liu Y, Yang G-Z, Giannarou Set al., 2018, Context aware decision support in neurosurgical oncology based on an efficient classification of endomicroscopic data., Int J Comput Assist Radiol Surg

PURPOSE: Probe-based confocal laser endomicroscopy (pCLE) enables in vivo, in situ tissue characterisation without changes in the surgical setting and simplifies the oncological surgical workflow. The potential of this technique in identifying residual cancer tissue and improving resection rates of brain tumours has been recently verified in pilot studies. The interpretation of endomicroscopic information is challenging, particularly for surgeons who do not themselves routinely review histopathology. Also, the diagnosis can be examiner-dependent, leading to considerable inter-observer variability. Therefore, automatic tissue characterisation with pCLE would support the surgeon in establishing diagnosis as well as guide robot-assisted intervention procedures. METHODS: The aim of this work is to propose a deep learning-based framework for brain tissue characterisation for context aware diagnosis support in neurosurgical oncology. An efficient representation of the context information of pCLE data is presented by exploring state-of-the-art CNN models with different tuning configurations. A novel video classification framework based on the combination of convolutional layers with long-range temporal recursion has been proposed to estimate the probability of each tumour class. The video classification accuracy is compared for different network architectures and data representation and video segmentation methods. RESULTS: We demonstrate the application of the proposed deep learning framework to classify Glioblastoma and Meningioma brain tumours based on endomicroscopic data. Results show significant improvement of our proposed image classification framework over state-of-the-art feature-based methods. The use of video data further improves the classification performance, achieving accuracy equal to 99.49%. CONCLUSIONS: This work demonstrates that deep learning can provide an efficient representation of pCLE data and accurately classify Glioblastoma and Meningioma tumours.

JOURNAL ARTICLE

Modi HN, Singh H, Orihuela-Espina F, Athanasiou T, Fiorentino F, Yang G-Z, Darzi A, Leff DRet al., 2018, Temporal Stress in the Operating Room: Brain Engagement Promotes "Coping" and Disengagement Prompts "Choking", ANNALS OF SURGERY, Vol: 267, Pages: 683-691, ISSN: 0003-4932

JOURNAL ARTICLE

Orihuela-Espina F, Leff DR, James DRC, Darzi AW, Yang G-Zet al., 2018, Imperial College near infrared spectroscopy neuroimaging analysis framework, NEUROPHOTONICS, Vol: 5, ISSN: 2329-423X

JOURNAL ARTICLE

Power M, Thompson AJ, Anastasova S, Yang G-Zet al., 2018, A Monolithic Force-Sensitive 3D Microgripper Fabricated on the Tip of an Optical Fiber Using 2-Photon Polymerization, SMALL, Vol: 14, ISSN: 1613-6810

JOURNAL ARTICLE

Singh H, Modi HN, Ranjan S, Dilley JWR, Airantzis D, Yang G-Z, Darzi A, Leff DRet al., 2018, Robotic Surgery Improves Technical Performance and Enhances Prefrontal Activation During High Temporal Demand., Ann Biomed Eng

Robotic surgery may improve technical performance and reduce mental demands compared to laparoscopic surgery. However, no studies have directly compared the impact of robotic and laparoscopic techniques on surgeons' brain function. This study aimed to assess the effect of the operative platform (robotic surgery or conventional laparoscopy) on prefrontal cortical activation during a suturing task performed under temporal demand. Eight surgeons (mean age ± SD = 34.5 ± 2.9 years, male:female ratio = 7:1) performed an intracorporeal suturing task in a self-paced manner and under a 2 min time restriction using conventional laparoscopic and robotic techniques. Prefrontal activation was assessed using near-infrared spectroscopy, subjective workload was captured using SURG-TLX questionnaires, and a continuous heart rate monitor measured systemic stress responses. Task progression scores (au), error scores (au), leak volumes (mL) and knot tensile strengths (N) provided objective assessment of technical performance. Under time pressure, robotic suturing led to improved technical performance (median task progression score: laparoscopic suturing = 4.5 vs. robotic suturing = 5.0; z = - 2.107, p = 0.035; median error score: laparoscopic suturing = 3.0 mm vs. robotic suturing = 2.1 mm; z = - 2.488, p = 0.013). Compared to laparoscopic suturing, greater prefrontal activation was identified in seven channels located primarily in lateral prefrontal regions. These results suggest that robotic surgery improves performance during high workload conditions and is associated with enhanced activation in regions of attention, concentration and task engagement.

JOURNAL ARTICLE

Thompson AJ, Power M, Yang G-Z, 2018, Micro-scale fiber-optic force sensor fabricated using direct laser writing and calibrated using machine learning, OPTICS EXPRESS, Vol: 26, Pages: 14186-14200, ISSN: 1094-4087

JOURNAL ARTICLE

Thompson AJ, Yang GZ, 2018, Tethered and implantable optical sensors, Implantable Sensors and Systems: From Theory to Practice, Pages: 439-505, ISBN: 9783319697482

© Springer International Publishing AG 2018. Optical imaging and sensing modalities have been used in medical diagnosis for many years. An obvious example is endoscopy, which allows remote wide-field imaging of internal tissues using optical fibers and/or miniature charge-coupled device (CCD) cameras. While techniques such as endoscopy provide useful tools for clinicians, they do not typically allow a complete diagnosis to be made. Instead, physical biopsies may be required to confirm or refute the presence of disease. Furthermore, endoscopic procedures are both invasive and time-consuming. As such, much research is currently directed toward the development of devices that can provide a complete in vivo diagnosis without the requirement for a physical biopsy. Ideally, such devices should also be minimally or non-invasive, and they should provide immediate identification of disease at the point of care. Additionally, there is significant interest in the development of implantable diagnostic devices that can be left within patients’ bodies for extended periods of time (for several days or longer). Such systems could be used for automated disease diagnosis, and example applications include the detection of post-surgical infections as well as monitoring of the health status of patients undergoing chemotherapy. This chapter focuses on the development of optical instruments that can provide in situ diagnosis at the point of care, with an emphasis on progress towards miniature devices that may function as implants in the future.

BOOK CHAPTER

Zhou X-Y, Lin J, Riga C, Yang G-Z, Lee S-Let al., 2018, Real-Time 3-D Shape Instantiation From Single Fluoroscopy Projection for Fenestrated Stent Graft Deployment, IEEE ROBOTICS AND AUTOMATION LETTERS, Vol: 3, Pages: 1314-1321, ISSN: 2377-3766

JOURNAL ARTICLE

Zhou X-Y, Yang G-Z, Lee S-L, 2018, A real-time and registration-free framework for dynamic shape instantiation, MEDICAL IMAGE ANALYSIS, Vol: 44, Pages: 86-97, ISSN: 1361-8415

JOURNAL ARTICLE

Anastasova S, Crewther B, Bembnowicz P, Curto V, Ip HM, Rosa B, Yang G-Zet al., 2017, A wearable multisensing patch for continuous sweat monitoring (vol 93, pg 139, 2017), BIOSENSORS & BIOELECTRONICS, Vol: 94, Pages: 730-730, ISSN: 0956-5663

JOURNAL ARTICLE

Anastasova S, Crewther B, Bembnowicz P, Curto V, Ip HMD, Rosa B, Yang G-Zet al., 2017, A wearable multisensing patch for continuous sweat monitoring, BIOSENSORS & BIOELECTRONICS, Vol: 93, Pages: 139-145, ISSN: 0956-5663

JOURNAL ARTICLE

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