Derek Gould

• Consultant at Royal Liverpool and Broadgreen University Hospitals NHS Trust

Segmentation is an important problem in various applications. There exist many effective models designed to locate all features and their boundaries in an image. However such global models are not suitable for automatically detecting a single object among many objects of an image, because nearby objects are often selected as well. Several recent wo...

Many effective models are available for segmentation of an image to extract all homogenous objects within it. For applications where segmentation of a single object identifiable by geometric constraints within an image is desired, much less work has been done for this purpose. This paper presents an improved selective segmentation model, without ‘b...

Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees' inexperience and the va...

Medical simulators provide a risk-free environment for trainee doctors to practice and improve their skills. UltraPulse is a new tactile system designed to utilise focussed airborne ultrasound to mimic a pulsation effect such as that of a human arterial pulse. In this paper, we focus on the construction of the haptics component, which can later be...

Medical simulators provide a risk-free environment for trainee doctors to practice and improve their skills. UltraPulse is a new tactile system designed to utilise focussed airborne ultrasound to mimic a pulsation effect such as that of a human arterial pulse. In this paper, we focus on the construction of the haptics component, which can later be...

Computer-based simulation for interventional radiology training has attracted increasing attention in recent years because of its potential to train remotely from patients and to provide objective assessment of proficiency. Yet developing a high fidelity simulator with realistic tactile feedback requires accurate knowledge of forces exerted on medi...

Interventional Radiology procedures (e.g., angioplasty, embolization, stent graft placement) provide minimally invasive therapy to treat a wide range of conditions. These procedures involve the use of flexible tipped guidewires to advance diagnostic or therapeutic catheters into a patient's vascular or visceral anatomy. This paper presents a real-t...

To establish how often off-label device and drug use occurs in interventional radiology (IR) in a UK tertiary referral hospital and consider the wider implications for the interventional radiologist. Prospective data were collected during interventional procedures for 1 working week in a university hospital. Out-of-hours procedures and procedures o...

The use of simulation to train skills has grown exponentially in the last few decades, especially in medicine, where simulator models can provide a platform where trainees can practice procedures without risk or harm to patients. Potential advantages of computer based simulator models over other forms of medical simulators include: (i) anatomical

This paper presents a virtual environment for training femoral palpation and needle insertion, the opening steps of many interventional radiology procedures. A novel augmented reality simulation called PalpSim has been developed that allows the trainees to feel a virtual patient using their own hands. The palpation step requires both force and tact...

Guidewire insertion is an imperative task of minimally invasive medical procedures. During the procedure, surgeons need to steer long flexible thin wires through patient's blood vessels to reach a clinical target. In this paper, we present a novel approach to model haptics of guidewire insertion process for training simulation. The algorithm also a...

Objectives: The aim of this article was to identify and prospectively investigate simulated ultrasound-guided targeted liver biopsy performance metrics as differentiators between levels of expertise in interventional radiology. Methods: Task analysis produced detailed procedural step documentation allowing identification of critical procedure st...

Guidewire manipulation is a core skill in endovascular interventional radiology procedures. Simulation-based training offers a valuable alternative for mastering these skills, but requires a faithful replication of complex guidewire behaviour inside the vasculature. This paper presents the integration of real flexural modulus (FM) measurements into...

Guidewire and catheter manipulation is a core skill in endovascular interventional radiology. It is usually acquired in an apprenticeship on patients, but this training is expensive and risky. Simulation offers an efficient alternative for core skills training, though the instrument complex behaviour requires accurate replication. This paper review...

Training in interventional radiology is slowly shifting towards simulation which allows the repetition of many interventions without putting the patient at risk. Accurate segmentation of anatomical structures is a prerequisite of realistic surgical simulation. Therefore, our aim is to develop a generic approach to provide fast and precise segmentat...

Simulating intrinsic deformation behaviors of guidewire and catheters for interventional radiology (IR) procedures, such as minimally invasive vascular interventions is a challenging task. Especially real-time simulations for interactive training systems require not only the accuracy of guidewire manipulations, but also the efficiency of computatio...

Debate on the existence of innate skills has all but evaporated in the light of evidence that it is only the hours spent in deliberate practice that correlate with even the most elite levels of expertise. A range of simple to advanced technologies stands to address some of the many challenges to effective training of 21st century, procedural medici...

Haptics technologies are frequently used in virtual environments to allow participants to touch virtual objects. Medical applications are no exception and a wide variety of commercial and bespoke haptics hardware solutions have been employed to aid in the simulation of medical procedures. Intuitively the use of haptics will improve the training of...

Endovascular clinicians use guidewires to navigate within vessels during angiography or angioplasty. In mastering this core skill, an alternative to the traditional apprenticeship in patients is provided by virtual training environments though these require a faithful replication of complex guidewire behaviours inside the vasculature. This paper pr...

An overview to medical simulation has been provided. In the context of procedural interventional radiology training, we start with the definition and history of simulation, address its increasing importance in medicine reflect on its theoretical basis and current evidence and finally review its advantages/ limitations and prospects for the future.

Commercial interventional radiology vascular simulators emulate instrument navigation and device deployment, though none supports the Seldinger technique, which provides initial access to the vascular tree. This paper presents a novel virtual environment for teaching this core skill. Our simulator combines two haptic devices: vessel puncture with a...

AIM: To determine face and content validity of a physics based virtual reality interventional radiology simulator, Imagine-S (Imaging guided interventional needle puncture simulation).

The base of all training in interventional radiology aims at the development of the core skills in manipulating the instruments. Computer simulators are emerging to help in this task. This paper extends our previous framework with more realistic instrument behaviour and more complex vascular models. The instrument is modelled as a hybrid mass–sprin...

KEY LEARNING OBJECTIVES: To determine face and content validity of a physics-based virtual reality (VR) training simulation of visceral interventional radiology needle puncture procedures. DESCRIPTION: Imaging-guided needle puncture procedures use hand-eye coordination to direct needles, wires and catheters to perform nephrostomy. The visuo-spatial...

This study evaluates AngioJet thrombectomy of occluded autogenous dialysis fistulae and polytetrafluoroethylene (PTFE) grafts in a UK hemodialysis population. Comparison is made with published data of alternative percutaneous thrombectomy methods. All patients with occluded dialysis fistulae who sought care at the Royal Liverpool University Hospita...

We present an integrated system for training visceral needle puncture procedures. Our aim is to provide a cost effective and validated training tool that uses actual patient data to enable interventional radiology trainees to learn how to carry out image-guided needle puncture. The input data required is a computed tomography scan of the patient th...

During a standard procedure of liver biopsy, the motion due to respiration may be difficult to handle. The patient is often requested to hold his breath or to breathe shallowly. Ideally, this physiological behaviour should be taken into account in a virtual reality biopsy simulator. This paper presents a framework that accurately simulates respirat...

Interventional Radiology is a rapidly expanding speciality using minimally invasive techniques to treat a multitude of clinical problems. Current work in progress aims to create an affordable virtual training tool to reduce training times and patient risk during a trainee practitioners learning cycle. The procedure of arterial catheterisation has b...

Erratum to: Cardiovasc Intervent Radiol (2007) 30:551–554.

Throughout the practice of procedural medicine, there is an unrelenting shift to management by less invasive techniques such as interventional radiology (IR). This subspecialty within radiology uses imaging to guide needles, wires and catheters using tiny access incisions. Like other minimally invasive techniques, risk, pain and recovery times are...

We present a prototype for a new virtual environment aiming at training interventional radiologists in the core skills involved in using catheters or guidewires. The instrument is modelled as a hybrid mass-spring particle system while the vasculature is a rigid triangulated surface mesh. A specially designed commercial haptic device allows the trai...

PURPOSE-MATERIALS: To use patient imaging as the basis for developing virtual environments (VE). BACKGROUND Interventional radiology basic skills are still taught in an apprenticeship in patients, though these could be learnt in high fidelity simulations using VE. Ideally, imaging data sets for simulation of image-guided procedures would alter dyna...

We present an integrated system for training ultrasound (US) guided needle puncture. Our aim is to provide a validated training tool for interventional radiology (IR) that uses actual patient data. IR procedures are highly reliant on the sense of touch and so haptic hardware is an important part of our solution. A hybrid surface/volume haptic rende...

Recent years have seen a significant increase in the use of Interventional Radiology (IR) as an alternative to open surgery. A large number of IR procedures commences with needle puncture of a vessel to insert guidewires and catheters: these clinical skills are acquired by all radiologists during training on patients, associated with some discomfor...

Change is often seen as threatening and is usually met with some resistance. Old methods are perceived to be 'safe' with change often disruptive in the short term. Patient choice, combined with appropriately trained and dedicated staff working as part of an integrated team, can vastly improve service provision for ultrasound patients. Simple change...

It is becoming increasingly difficult to learn interventional radiology (IR) skills because there are fewer "straightforward" invasive diagnostic imaging studies, a reduction in the time available for training, concerns about patient safety, and changing patient perceptions. Computer-based simulation has the potential to allow an operator to realis...

Training in interventional radiology (IR) relies on a traditional apprenticeship; to protect patients, expert supervision is mandatory until knowledge, attitudes and practical skills have been certified as satisfactory. However, the current quality of IR training is threatened by reduced time for trainees to learn, as well as a loss of basic diagno...

The medical domain provides excellent opportunities for the application of computer graphics, visualization and virtual environments, with the potential to help improve healthcare and bring benefits to patients. This survey paper provides a comprehensive overview of the state-of-the-art in this exciting field. It has been written from the perspecti...

To identify, describe and detail the cognitive thought processes, decision-making, and physical actions involved in the preparation and successful performance of core interventional radiology procedures. Five commonly performed core interventional radiology procedures were selected for cognitive task analysis. Several examples of each procedure bei...

Transjugular intrahepatic portosystemic stent shunt (TIPSS) is now widely used in the treatment of uncontrolled and recurrent variceal haemorrhage. This study reports the outcome and long-term follow-up of 125 patients who were referred to a single centre for TIPSS. One hundred and twenty-five patients were referred to undergo TIPSS. All but 10 had...

to examine the effect of stent-graft deployment on pressure within an aneurysm sac and to investigate the potential sources of intra-sac pressure. intra-sac pressure was monitored during and immediately after endovascular repair via an indwelling catheter. Intra-sac pressure was also monitored during conventional open repair and was compared with t...

To illustrate the possible peri- and postprocedural complications of stent treatment for Takayasu arteritis and suggest ways of reducing these risks. A 69-year-old woman with Takayasu arteritis had multiple stents implanted in the aortic arch (3 Memotherm) and main branches of the thoracic aorta (individual Corinthian stents in the subclavian and b...

Perianeurysmal fibrosis (PAF) with involvement of neighbouring viscera can render open repair of inflammatory aneurysms technically difficult and therefore hazardous. For this reason, endovascular repair (EVAR) has been advocated as the preferred approach for this condition. EVAR is known to induce a systemic inflammatory response in patients but t...

To assess the feasibility of embolization of aortic side branches and its impact on the incidence of type II endoleak after endovascular aneurysm repair. Endovascular aneurysm repair was performed in 74 patients. Aortic side branch vessels were evaluated on the preoperative angiogram and computed tomography (CT) and, where embolization of lumbar an...

Purpose: To investigate the incidence, significance, and mechanism of stent-graft distortion after endovascular repair (EVR) of abdominal aortic aneurysm. Methods: EVR of abdominal aortic aneurysm was performed in 51 cases (49 modular, bifurcated; 2 tube). Thirty-two patients were followed for 6 or more months and had equivalent baseline and follow...

To determine whether freedom from endoleak after endovascular repair of abdominal aortic aneurysm (EVAR) is a reliable guide to freedom from persistent or recurrent pressurisation of the aneurysm sac (endotension) and therefore freedom from risk of rupture. The records of 55 patients followed for more than 3 months after EVAR were reviewed to corre...

To document the expression of oncofetal antigens and steroid receptors in first trimester human fetal ovaries and to determine the effect of advancing gestation on expression patterns. Fetal gonads were collected from surgical terminations of pregnancy, and fetal sex was determined by fluorescence in situ hybridization. Immunocytochemical analysis...

In the ongoing evolution of a categorization system for endoleak, the authors propose the term endotension to define persistent or recurrent pressurization of the aortic aneurysm sac after endovascular repair. Endotension is evidence that the aneurysm remains at risk of rupture and should, therefore, be considered an indication for secondary interv...

Ten women underwent obstetric hysterectomy at St George's Hospital, London between 1992 and 1998, with an apparent seven-fold increase in incidence in recent years. All hysterectomies were performed as emergency procedures, with massive postpartum haemorrhage being the major indication for operation in nine cases. Abnormal placentation was the sing...

To report the incidence of delayed complications following endovascular abdominal aortic aneurysm (AAA) repair and the relationship of these sequelae to morphological changes in the sac and endograft. Twenty-six AAA patients treated with Vanguard endografts had completed > or = 1-year follow-up. Postoperative angiograms and spiral computed tomograp...

Amniotic band syndrome is a well described clinical entity presenting with deformities of the limbs, thorax, craniofacial skeleton, soft tissues and umbilical cord, but it still lacks a precise definition and a coherent hypothesis for its pathogenesis. We report on a case of first trimester diagnosis of amniotic band syndrome by sonography and feto...

Case report Five women, all of whom presented within a 12-month period, were referred to the division of gynaecological oncology following acute admission with iliofemoral vein thrombosis and the subsequent finding of a large pelvic mass due to a suspected gynaecological malig-nancy. Three of the five women also presented with tachypnoea, dyspnoea...

Primary pancreatic neoplasm typically presents at an advanced stage where surgical management may not be feasible. These patients are often symptomatic due to biliary obstruction but problems may also include gastrointestinal bleeding and endocrinological complications. We describe two cases illustrating the use of palliative embolization in the co...

Percutaneous transluminal angioplasty (PTA) of the superior mesenteric artery (SMA) and coeliac axis (CA) is a well recognized form of treatment for patients with chronic intestinal ischaemia and carries a low morbidity and mortality. We report a case where PTA of the inferior mesenteric artery in the presence of occluded SMA and CA proved both fea...

Heparin-induced thrombocytopenia is an infrequent complication of heparin which causes thrombocytopenia and thrombosis. The vascular radiologist can expect to come across several cases in his/her career. A high index of suspicion is required for early diagnosis. This may befall the radiologist who is asked to provide thrombolytic treatment in a hep...

Seventeen of 20 (85%) patients on RDT for six to 13 years were found to have acquired renal cysts. There was a significant positive association between Hb and duration of RDT. The extent of cyst was positively and significantly correlated with the latest Hb and years on dialysis. There was also a significant positive correlation between size and ye...

Bei mehrstündigem Erhitzen auf Temperaturen über 70°C, der Zerfallstemperat des Trioxids (I), reagiert dieses mit N2F4 oder S2O3F2 zu den Trifluormethylo Derivaten (II) bzw. (III) (87% Ausbeute).

Reactions of bis(trifluoromethyl) trioxide, CF3OOOCF3, with a variety of inorganic compounds are described. The trioxide is shown to be a convenient source of compounds containing CF3O- and CF3OO- groups. Improved syntheses of the previously reported CF3ONF2, CF3OOSO2F, and (CF3O)2SF4 are described, and the new compounds CF3OOSO2OCF3,cis-CF3OOSF 4O...

Aus den Polyfluoralkylhypochloriten (I) und den Olefinen (II) werden die Addukte (III), aus Pentafluorschwefelhypochlorid (IV) und (II) die analogen Addukte (V) erhalten.

Perfluor-tert.-butylalkohol (I) und Chlortrifluorid (II) reagieren bei 20°C zum Peroxid (III) (50 - 70% Ausbeute).

Complexes of F3NO with the Lewis acids BF3, AsF5, and SbF5 were found to exist in the ionic form F2NO+A-, where A- = BF4-, AsF6-, or SbF6-. Infrared spectra of the solid complexes as well as infrared, nmr, and conductivity studies of the complexes dissolved in polar fluorinated solvents confirm their ionic constitution and indicate that the F2NO+ c...