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Flashcards in Imaging of Cardiac Pathology Deck (10)
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1

what are the types of imaging available?

•echo •nuclear •CT scans

2

most common use of testing

•determination of function/valve anatomy •diagnosis of myocardial ischemia •determine the severity of CAD •non-invasive hemodynamics •prognosis

3

critical features of imaging

•risk/benefit ratio •comprehensive capabilities -muscle, flow and/or artery •accuracy •reproducibility •overall cost to society (misdiagnosis) •length of examination and interpretation •accessibility •portability

4

muscle

•echocardiography •cardiac MRI

5

flow

•nuclear SPECT •cardiac MRI

6

artery

•computed tomography •cardiac MRI •angiography

7

transthoracic echo

Inexpensive (relatively)

No risks / discomfort

Non-radiating

Non-nephrotoxic contrast agents

Comprehensive morphology / physiology

Ideal for serial exams

 

Sound above human hearing (20,000Hz) Piezo-electric crystals are struck by alternating electric currents and create these high frequency vibrations Transducers send and receive signals Pulsed-reflected US through the heart provides the position and motion of cardiac structures

can convert velocity to pressure using Bernoulli Equation

pressure = 4 * Vsquared

 

•tricuspid regurgitation to dteremine peak pulmonic arterial pressure 

-pulmonary hypertension

•velocity across aortic valve to measure peak aortic pressure

-aortic stenosis

8

nuclear SPECT

Single

Photon

Emission

Computed

Tomography

Dominant non-invasive diagnostic test

 6 million / yr in US.

 Sensitivity 80-90%; specificity, 75-85%

Drawbacks

 Attenuation of signal = false positives

 Increased signal (hepatobiliary uptake)

 Ionizing-radiation exposure

 Long duration of test

9

CT angiography

•excellent method of assessing patients

•vein grafts

*arterial grafts

 

10

cardiac MR

Magnetic resonance occurs only in atomic nuclei with unpaired spin

MR does not interfere w/ electrons in the outer shell

 Fundamentally safe

 Unlike ionizing radiation (x-rays) which bind to electrons and potentially alter DNA

Advantages:

Function (+ stress)

Perfusion

Delayed enhancement VIABILITY

Coronary wall

No radiation

No renal toxicity

Disadvantages

Availability

Off-line interpretation

Gating / motion artifact

Pacemakers / ICD

High tech / MD skills

Distorted ECG