Mod5 (diagnostic imaging)

Question 1

cardiothoracic ratio

Answer 1

adult heart should occupy less than or equal to 50% of thorax width; used to account for variation in body habitus

Question 2

Hypertrophy

Answer 2

increase in bulk, results in overall muscle mass rather than chamber size; NOT detectable on x-ray

Question 3

Heart Failure

Answer 3

blood can’t pump out sufficient enough blood to meet bodies metabolic needs

Question 4

Cardiomegaly

Answer 4

enlargement of heart; usually above 50% cardiothoracic ratio

Question 5

Pulmonary Edema

Answer 5

fluid in the lungs

Question 6

Pleural Effusion

Answer 6

fluid in pleural cavity

Question 7

Pulmonary Embolism

Answer 7

blocking of pulmonary artery; will see changes in pulmonary blood flow patterns with use of x-ray

Question 8

Pulmonary Hypertension

Answer 8

increased resistance in artery; diagnosed by x-ray as changes in appearance of pulmonary artery

Question 9

2D imaging (B-mode)

Answer 9

ultrasound mode; to obtain a cross-sectional (Real time) image of the heart

Question 10

M-mode

Answer 10

ultrasound mode; 2D imaging used to find placement of M-mode; amplitude of signal is recorded along length of single beam; great at evaluating opening and closing of valves

Question 11

Doppler Technique

Answer 11

ultrasound mode; detects direction and average speed of blood flow (velocity); based on diffs btw freq of transducers and blood cell freq signal

Question 12

Doppler Shift

Answer 12

change in frequency of a wave for an observer moving relative to its source

Question 13

Tissue Doppler Imaging

Answer 13

tracks movement of cardiac tissue and is of low velocity; useful method of assessing regional differences in cardiac wall function

Question 14

3D imaging

Answer 14

ultrasound mode; obtains 3D volumes of systolic and diastole to determine QUANTITATIVE EJECTION FRACTION; especially ***useful for diagnosing myocardial ischemia

Question 15

frontal view of heart (x-ray)

Answer 15

gives assessment of overall size; produces posterior-anterior view

Question 16

Lateral view of heart (x-ray)

Answer 16

to view patients left side; x-ray passes from R-L

Question 17

Echocardiography

Answer 17

use of ultrasound waves to visualize structure and function of heart; relies on difference of tissue density to produce image constructed from reflected waves (TTE, contrast, stress, transesophageal)

Question 18

pulsed wave (pw) doppler

Answer 18

analyzes blood flow at specific sample points; only at low velocities; determines exact location of left ventricular outflow obstruction

Question 19

continuous wave (cw) doppler

Answer 19

records along entire length of cursor; records higher velocities; determines peak gradient across stenotic valve

Question 20

colour flow mapping doppler

Answer 20

same principle as pw doppler (sample at specific pt, low velocities); colour used to rep average velocity of blood flow; to observe regurgitation/shunts

Question 21

Transthoracic echo (TTE)

Answer 21

patient lies on side; Uses five windows to obtain views of the heart; views allow observation of heart w/o obstruction from ribs/lungs

Question 22

Contrast echo

Answer 22

enhance endocardial border definition; uses contrast agent to assess ejection fraction and visualize thrombus. used when TTE is not adequate

Question 23

stress echo

Answer 23

determines wall motion abnormalities from exercise/drug-induced stress; useful at diagnosing myocardial ischemia/CAD

Question 24

Transesophageal echo (TEE)

Answer 24

provides clearer image of TTE without interference from lungs/bones; assess endocarditis, preoperative assessment, exclusion of embolism and septal defects

Question 25

Clinical App of Echo

Answer 25

ventricular assessment and ejection fraction calculation, view valvular lesion, assess wall motion abnorm, diagnose cardiomyopathy/pericardial disease

Question 26

Myocardial perfusion imaging

Answer 26

type of nuclear cardiology; determines ischemia/infarction from CAD; acquire image using SPECT; areas of infarct show lack of thallium accumulation (COLD SPOTS)

Question 27

Hibernating Myocardium

Answer 27

when both sets of images (before/after exercise) show persistent cold spots in absence of scarring

Question 28

MIBI (99 Sestamibi)

Answer 28

nuclear cardiology; demo relationship btw amount absorbed by myocardium in relation to blood flow; distribution reflects delivery of blood (perfusion)

Question 29

MUGA (multi-gated acquisition nuclear scan/ radionuclide ventriculography)

Answer 29

evaluates ventricular systolic function; technetium 99m injected and binds to RBCs; determines ejection fraction

Question 30

First pass MUGA

Answer 30

obtains rapid sequential cardiac images during INITIAL passage of tracer through heart/vessels; assess extent of L-R cardiac shunts

Question 31

Gated Equlibrium MUGA

Answer 31

continous imaging of heart chambers at PREDETERMINED TIME(gate) after QRS

Question 32

Positron Emssion Tomography (PET)

Answer 32

positron emitting isotope (rubidium 82) attaches to metabolic tracer (FDG); areas of decrease blood flow show increased FDG uptake; to assess myocardial metabolism and perfusion

Question 33

CT (Computed tomography)

Answer 33

detailed anatomic cross-sections of thorax; to visualize size, shape, and wall thickness of chambers and great vessels

Question 34

Magnetic Resonance Imaging (MRI)

Answer 34

powerful magnetic fields and non ionized radio frequency radiation applied to body; image created when radio-freq is suddenly discontinued; differentiate small contrasts in tissue

Question 35

Coronary Magnetic Resonance Angiography

Answer 35

differentiates laminar blood flow from turbulent blood flow (turbulent from obstruction/narrowing from stenosis)

Question 36

contrast enhanced MRI

Answer 36

differentiate btw impaired but viable tissue from scarred unviable tissue