The Normal Canine Heart: Anatomical Criteria for the Study of Real-Time Ultrasonography and Doppler Echocardiography

Veterinary science, Morphology

Paterson, Calum

University:University of Glasgow

关键词: Veterinary science, Morphology;   

Others  :  http://theses.gla.ac.uk/78136/1/11007440.pdf

来源: University of Glasgow

【 摘 要 】

The present work has two main objectives, firstly, to establish acriterion that enables the successful, real - time imaging of the canine heart, and secondly, to carry out a Doppler ultrasound study of the bloodflow signatures that occurr across the various heart valves. The historical development of ultrasound, (Chapter 1) describes the early applications of the technique in relation to shipping as a navigational aid, and also to industry where it is employed to detect flaws in metals. The scientific review in the same chapter, establishes the uptake of ultrasound as a tool for echocardiography in the early 1950's, but only in the M-mode format. It is not until the 1980's that the real-time echocardiography of the dog heart is studied in any detail. To date, the only reports of Doppler echocardiography in the dog are those describing cardiac abnormalities. The normal ultrasonic anatomy of the heart combined with the Doppler bloodflow patterns through the heart valves has not been fully explained. The practical physics of ultrasound is described in Chapter 2, and provides information on the acoustic physics and principles of the ultrasonic images. The common artifacts encountered in an ultrasonic examination, such as reverberation and absorption, are discussed along with basic information about various types of transducers and ultrasound scanners employed in all aspects of ultrasonic investigations. In Chapter 3, a detailed description of Doppler ultrasound is explained. This includes the description of the principles of Doppler ultrasound, the Doppler spectrum, and the differing types of bloodflow encountered during a Doppler echocardiographic examination. The various modes of Doppler ultrasound (pulse-wave and continuous wave) are also described to allow a comprehensive understanding of the subject. The procedures and disciplines, along with the equipment employed in the study are outlined in Chapter 4. The importance of the scanner adjustment via the depth, gain and power controls are identified along with the selection of the proper transducer frequencies required for the different scanning planes. Images of the dog heart are recorded in four positional planes; the right and left parasternal, subcostal and suprasternal. The positioning of the transducer and the anatomical structures to be found in these imaging planes are identified. In Chapter 5, the images of the heart recorded are displayed in both colour and black and white prints, with the anatomical structures annotated. The echocardiographs are displayed in all the imaging planes using a combination of real-time and M-mode ultrasound, along with pulsed wave and continuous wave Doppler. The results of the present work are explained in Chapter 6. They include a detailed description of the anatomical structures that are found during the various scans. The bloodflow velocities of the various heart valves (mitral, tricuspid, aortic and pulmonary) are measured as well as the left ventricular function of the heart.