Cardiopulmonary diagnostic testing and interventions Flashcards
why would a chest x-ray be ordered?
1) cardiomegaly
2) congestive heart failure
3) valve dysfunction
4) differential diagnosis pulmonary conditions
cardiomegaly
cardiothoracic ratio (maximum width of the heart/maximum internal diameter of the thoracic cage > 50% considered positive; some limitations
common types of chest radiography
- posterior.anterior view, anterior-posterior view, lateral view
- assess density of various structures, are findings normal?, and is there any consistency (right vs. left)
echocardiography
1) cardiac echo: non-invasive procedure using high frequency ultrasound waves to create images to assess the function of the heart
2) size of the ventricle, integrity and thickness of the ventricular walls and septum, valve integrity and health, volumes of ventricle, ejection fraction can be estimated
2D echocardiography
depicts anatomic relationships and movement of cardiac structures relative to one another; wall and valve motions; intracardiac masses; measures ventricular thickness, contractile function and ejection fraction
Doppler imaging
depicts blood flow direction and velocity; identifies regions of vascular turbulence (usually seen distal to a stenosis); color flow mapping show the location of stenotic and regurgitant valves and other blood flow issues in the heart and vena cavae and aorta
echocardiography
- uses pulse of reflected ultrasound to evaluate the functioning of the heart
- provides real-time images of beating heart
- information derived - size of ventricular cavity, thickness, and integrity of interatrial and intraventricular septa, functioning of valves, motion of individual segments of ventricular wall
- quantify volumes of left ventricle, estimate SV and ejection fraction
CT-Computed tomography
- CT uses a series of thin x-rays to generate cross sectional images of the heart, vasculature and pulmonary vasculature
- x-ray device rotates around patient and the generated beams are partially absorbed by body tissues. the remaining beams emerge and are captured as images
- often requires administration of an intravenous contrast agent to distinguish between blood and tissue
- CT used for great vessels, pericardium, myocardium, and coronary arteries
- CT used to diagnose aortic dissections and aneurysms myocardial abnormalities; intracadiac thrombus formation
- limitation: artifact from patient moving and breathing; radiation
spiral CT
- helps guard against this as it is quick enough to get images while the patient is holding breath; lower radiation; very useful for the detection of PE
EBCT
electron beam CT uses a direct electron beam to acquire images in milliseconds (during a single cardiac second)
CT uplmonary angiography (CT-PA)
- direct visualization of the pulmonary arteries and can detect a thrombus
- becoming more preferred diagnosis of pulmonary embolism (PE)
- benefits: rapid reporting, high sensitivity and specificity, widely available
0 3rd most common acute CVD is PE … estimated 200,000-300,000 annually in US
cardiac MRI (CMR)
- uses a powerful magnetic field to obtain images of internal structures; requires no ionizing radiation
- best at differentiating tissue types (especially soft tissue); often without the use of contrast dyes
- used to diagnose congenital anomalies, diseases of the aorta including dissection and aneurysm
- used to assess ventricular mass and volume, intravascular thrombus, cardiomyopathies, pericardial disease, and cardiac cancers
- captures images at discrete times in the cardiac cycle used for evaluating valvular and ventricular function
- better for patients with kidney dysfunction or allergy to contrast dye
coronary magnetic resonance angiography (coronary MRA)
non-invasive, contrast-free way to image the coronary arteries
contrast-enhanced MRI
contrast agent used post MI to differentiate between damaged but salvageable and infarcted (non-reversible) cardiac tissue
positron emission tomography
- nuclear technique that provides visualization and direct measurement of metabolic functioning
- gold standard for blood flow measurement
- costly
- advantage - can detect jeopardized by viable myocardium without exercise