Biomedical subjects

D M Cavaye

Publications and source records attributed to D M Cavaye.

25 records · Page 2Linked to original sources

PubMed1991

Intraluminal ultrasound assessment of vascular stent deployment.

This study assessed the utility of intraluminal ultrasound imaging during deployment of a self-expanding vascular stent and quantitated changes in arterial morphology produced by the stent. Cross-sectional images of arterial lumens (n = 50) were obtained before stenting, in-vitro (n = 35) from formalin-preserved human superficial femoral arteries and in-vivo (n = 15) from canine iliac arteries containing laser-induced eccentric stenoses. Comparison of ultrasound-derived vessel dimensions (minimum and maximum diameter and cross-sectional area) with histological morphometric analysis of corresponding vessel sites showed good correlation by linear regression analysis (r = 0.930-0.987, p = 0.001-0.005). Following stent placement, 23 intraluminal ultrasound images were obtained from the stented vessel sites (in-vitro n = 15, in-vivo n = 8) and were compared to prestented cross-sectional areas. In the in-vitro vessels there was a small increase (p = 0.023) in area, but there was no change in the in-vivo arteries (p = 0.6). To assess the effect of stenting on luminal shape (ellipticity), minimum/maximum diameter ratios were compared before and after stent deployment. There was an increase in this ratio in the in-vitro vessels (p = 0.001) but no change in the in-vivo arteries (p = 0.2). We conclude that intraluminal ultrasound produces clear and accurate images of the location, shape and degree of arterial pathology, ensuring good stent: vessel size matching and immediate quantitative assessment of the effects of arterial stent placement.

Animals↗

PubMed1991

Intravascular ultrasound imaging of an acute dissecting aortic aneurysm: a case report.

A case of acute dissecting aortic aneurysm is described in which intravascular ultrasonography was used at the time of aortography to produce real-time, 360 degree cross-sectional images of the aorta. The transmural vessel morphology visualized by this new catheter-based technology allowed confirmation of the diagnosis and identification of distal extension to the aortic bifurcation. The case demonstrates the unique potential of this modality in diagnosis and possible therapy in vascular diseases.

Acute Disease↗

PubMed1991

A new technique for intraluminal hollow organ imaging: three-dimensional ultrasound.

Intraluminal ultrasound (ILUS) is a new catheter-based system which produces two-dimensional (2D), cross-sectional images of tubular structures. The principle of image acquisition using 5.0 Fr (30 MHz) and 8.0 Fr (20 MHz) ILUS catheters containing ultrasound transducers at the tip, is equally applicable to all tubular or hollow organs. This article illustrates the feasibility of intraluminal imaging of hollow organ structures, and describes computerized three-dimensional (3D) reconstruction of the 2D images, using a PC-based image analysis system. A set (n = 90) of longitudinally aligned, consecutive 2D images was sampled from various organs (canine bladder, urethra, jejunum, esophagus, and trachea) and computer processed to produce 3D images. By adjusting image density threshold and viewing angle, the lumen and wall morphology can be examined in any projection. Possible applications include diagnosis of lumen encroaching pathology, guidance of intraluminal instruments, and assessment of the effects of endoluminal interventions.

Animals↗

PubMed1991

Three dimensional vascular ultrasound imaging.

Intravascular ultrasound (IVUS) is a new catheter-based system that produces two-dimensional (2D) images of vascular structures. Existing systems produce real-time, cross-sectional "slices" of vessels using 5.0 French (Fr) (30 MHz) and 8.0 Fr (20 MHz) IVUS catheters containing ultrasound transducers at the tip. Computerized, three-dimensional (3D) reconstruction of these 2D images using a personal computer- (PC) based image analysis system is described. A set (n = 90) of longitudinally aligned, consecutive images is sampled from a 5.0 cm vessel segment, and computerized processing creates rendered 3D images. By adjusting image density threshold and viewing angle, the morphology, location, and spatial distribution of arterial pathology can be seen. Refinements in computer hardware and software have reduced processing time and improved image resolution to the point where 3D IVUS imaging is a clinically applicable tool. Possible applications include diagnosis of complex arterial pathology, guidance of intraluminal instruments, and assessment of the effects of endovascular interventions.

Blood Vessels↗

PubMedDate not supplied

The practice of carotid endarterectomy in Australasia.

BACKGROUND: Carotid endarterectomy (CEA) is a frequently performed surgical procedure and there are variations in the preoperative, operative and postoperative management related to this operation. METHODS: Questionnaires were sent to all 191 members of the Division of Vascular Surgery, Royal Australasian College of Surgeons, and the Australasian Chapter of the International Society of Cardiovascular Surgery. RESULTS: The questionnaire was returned by 179 surgeons (94%). One hundred and fifty-nine were vascular surgeons, of whom 139 perform CEA. Most surgeons reported performing more CEA than 5 years previously. Surgery for asymptomatic carotid stenosis was performed by 78% of surgeons at the time of the survey. Routine carotid angiography is performed pre-operatively for symptomatic patients by 61% of surgeons and for asymptomatic patients by 56%. Intra-operative shunting is used routinely by 37% of surgeons, selectively by 58% and never by 5%. Arteriotomy patch closure is performed routinely by 16%, usually by 30%, rarely by 52% and never by 3%. The favoured patch material is Dacron 39%, PTFE 19%, ankle long saphenous vein (LSV) 22%, thigh LSV 18% or other materials 2%. Compared to their practice 5 years previously, arterial patch closure is used more often by 42% of surgeons, the same by 51% and less by 7%. Postoperatively, patients are nursed mainly in intensive care (34%) or a high-dependency unit (33%). CONCLUSIONS: The practice of CEA by Australasian vascular surgeons reflects the recent trends reported in the world literature. Most Australasian surgeons perform CEA for asymptomatic disease. Forty per cent are performing CEA on the basis of duplex scanning alone. There is a trend towards increased use of patch closure. Most patients are managed in intensive care or high-dependency units.

Aged↗

PubMedDate not supplied

Computerized surgical databases: introduction to design and function.

There has been an enormous increase in the variety and volume of information encountered in surgical practice, either as measurable clinical variables or laboratory research data over the last three decades. Despite its form and origin, this information remains the basis of both daily clinical decision making and analytical research. Inferences drawn from past experience will modify an individual's approach to disease and treatment. However, when the demands of information processing cannot be met, mischief begins and quality of care declines. Modern computers offer an extraordinarily powerful method of processing the large volumes of medical data that are acquired, and provide techniques for analysis that would have been impossible, and often inconceivable, without computers. The applications of computer technology to surgical data management range from such simple and repetitive tasks as practice administration and accounting to elegant statistical and image analysis. This paper outlines the utility of computerized data management in clinical surgery and surgical research, and describes techniques for designing and implementing a customized surgical database system.

Computers↗

PubMedDate not supplied

Endoscopic surgery training: application of an in vitro trainer and in vivo swine model.

The development of endoscopic surgical procedures is changing general surgery, with many operations such as cholecystectomy, appendectomy, and hernia repair being performed using laparoscopic surgical techniques. Training and credentialing of surgeons are key issues for the safe and ethical introduction of these new procedures. This article reviews techniques employed at our institution for laparoscopic surgical training and certification including didactic instruction, an in-vitro model for learning instrumentation and hand-eye coordination, and in-vivo training using the porcine animal model.

Animals↗