Cardiovascular Imaging Flashcards

Question

M (Motion) -Mode Trace Curves

Answer 1

The "M" mode using a stationary transducer but a moving recording scanning the ultrasound pattern across the screen so it is possible to study the dynamics of moving structures such as the ventricular wall or the valve leaflets

Answer 2

The combination of Doppler and "M" mode demonstrates the Haemodynamics of Blood flowing within the Heart

Answer 3

* MRI uses a large magnet that surrounds the patient by a magnetic field up to 8,000 times stronger than that of the earth. Like CT, MRI produces images, which are the visual equivalent of a slice of anatomy. MRI, however, is also capable of producing those images in an infinite number of projections through the body

Answer 4

people dependent upon cardiac pacemakers those with metallic foreign bodies in the brain or around the eye.

Answer 5

Both Anatomical and Functional

Answer 6

MRI produces images by decoding radiofrequency signals emitted from the body’s hydrogen atoms The scanner subjects nuclei of the body's atoms to a radio signal, temporarily knocking select ones out of alignment. When the signal stops, the nuclei return to the aligned position, releasing their own faint radio frequencies from which the scanner and computer produce detailed images of the human anatomy

Answer 7

Functional studies are obtained by stacking images acquired from separate time points of the cardiac cycle in a cine-loop

Answer 8

Gamma Camera detects the source of the radiation to build a picture: - Multihole collimator for direction of flux - Lead shield to minimize background radiation - Scintillation crystal - Photo-multiplier tubes - Detector

Answer 9

The test is done 12 hours after a suspected heart attack. The scanning is performed 3 hours after the isotope is injected and the image acquisition takes about 1hr The technetium accumulates in heart tissue that has been damaged, leaving "hot spots" that can be detected by the scintillation camera.

Answer 10

* The Nuclear heart scan uses technetium Tc-99m as it has a short physical half life = 6 hours= the amount of radioactive exposure is limited + provides better image quality than previously used radioactive agents such as thallium because it has a shorter half life and can thus be given in larger doses. * The study is repeated after several weeks to determine if any further damage has occurred * Clinical studies demonstrate that technetium heart scans are just as or more accurate in detecting heart attacks as electrocardiogram findings

Answer 11

Multiple images taken at different rotation angles to obtain 2-D matrix 3-D picture can be reconstructed using the source information

Answer 12

* These scans are used to study blood flow to the heart and can indicate conditions that could lead to a heart attack. * MPS is a non-invasive nuclear imaging technique that uses radioactive imaging agents to assess the coronary blood flow to the LV myocardium. * Radioactive tracer injected into vein travels through coronary arteries and settles into LV myocardium. * A narrowed/diseased coronary artery will not allow as much tracer through it as a normal one resulting in reduced amount of tracer to settle in the effected area of myocardium

Answer 13

A narrowed vessel results in less tracer reaching the effected myocardium

Answer 14

* Exercise causes coronary dilation * In patients that have CAD exercise exaggerates the narrowing of coronary arteries. * Comparison of rest and stress images differentiates between reversible ischemia and established myocardial infarct * Treadmill exercise * Pharmacologic stress agents: Adenosine + Dobutamine

Answer 15

* Summed images are used to assess cardiac perfusion. Rest and Stress images are compared to determine if a region of the heart is “ischemic” – starved of oxygen * In the study below, the rest image indicates normal blood flow, but the stress image indicates abnormal blood flow in the Inferior-lateral region. This indicates a stenosis in the left coronary artery

Answer 16

Good perfusion seen on both Stress (top line) and Rest (lower line)

Answer 17

Poor perfusion on stress (top) but better perfusion on rest to indicate reversible ischemia (lower)

Answer 18

Poor perfusion on both Stress (top) and Rest (lower) imaging to indicate established MI

Answer 19

* MP scans provide excellent negative predictive value. Patients from the general population with normal scans have <1% annual risk of cardiac events. * MPS is a non-invasive test and therfore cannot intervene directly

Cardiovascular Imaging Flashcards

(46 cards)