Ch 14 IMT Flashcards
When does atherosclerosis develop?
Slowly starting from childhood + proceeds into adulthood (pt’s are susceptible to complications)
What is the first structure detected by u/s indicating atherosclerosis?
Increased IMT (intimal media thickness)
Increased IMT is the result of what nonatherosclerotic processes?
-Smooth muscle cell hyperplasia
-Fibrocellular hypertrophy
List 3 reasons as to why there may be an increased IMT?
-Atherosclerosis
-Nonatherosclerotic processes
-Response to changes in flow, wall tension or lumen diameter
Who would get an IMT test?
Pt’s at moderate risk for having cardiovascular disease
IMT results are used in conjunction with what other 2 tests?
Calcium score test or framingham risk score
What is a calcium score test?
-CT scan that shows how much calcium is in coronary arteries
-Tells us if there is plaque in the arteries that can narrow/block them
What can atherosclerosis lead to?
Heart attack
What is the framingham risk score?
Tool for assessing the risk level of CAD over 10 years
What are the 6 coronary risk factors that the framingham risk score considers?
-Age
-Gender
-Total cholesterol
-High density lipoprotein cholesterol
-Smoking habits
-Systolic BP
When would an IMT measurement not be recommended?
-Not a routine measurement done in clinical for a risk assessment for a first time atherosclerotic cardiovascular disease event
-Serial IMT studies are not recommended
Which probe should we use for an IMT exam?
High frequency 12-15Mhz
Define IMT?
Double line pattern on both walls of the CCA in SAG
(the lumen-intima + media-adventitia interfaces form the 2 parallel lines)
What is the main challenge with IMT measurements?
Significant differences in how the measurement is performed
Should we use zoom when performing an IMT measurement?
No!
What are the standard IMT settings on the machine?
-B mode >7Mhz with minimal compression
-Footprint at least 3cm
-Focus depth (30-40mm)
-FR (>15-25 Hz)
What landmark should be included in our IMT image to provide accurate serial measurements?
Carotid bif
Where should we obtain our IMT measurement?
Segment free of atherosclerotic plaque with clearly defined lumenn-intima + media-adventitia interfaces
How long is our IMT measurement?
10mm
Is the far or near wall of the CCA better to measure?
Far wall
What window is preferred for best resolution?
Lateral/coronal window
Is insonation from multiple angles recommended?
No! Assess in SAG + perpendicular to beam
The IMT measurement must be how many mm below the distal CCA?
5mm
Is point-to-point measurement of IMT recommended?
No!
