measure of relative density (WATER IS ZERO) (Air<Fat< Water< Soft Tissue< Calcium< metal)
By adjusting the gray scale level one can...
differentiate between the ventricles of the heart
IN ANOTHER WINDOW
detail the air ways of the lungs
Anatomy: Brain, Neck, Chest, ABD, pelvis, bone
Contrast: Oral, IV, other (rectal, bladder)
Slice Thickness: (0.6-10mm)
Scan Timing: breath hold, arterial, venous, delayed phase
Be able to ID the type of contrast:
IV contast vs Oral contrast
IV contrast: the density within the aorta will be similar to that of the vertebrae
Oral contrast: you will see difference in the tissue within the observable intestine.
**** Enhancing (Solid) renal mass
an increase in H.U (density) from pre to post contrast
*** PRE contrast required
Is CT sensitive enough for gall stones?
NO!!!! (ok sometimes)
they are the same density as the fluid around them
***Ultrasound is much better for this DX
Inject intravenous contrast
obtain scan during the arterial phase
Helical CT (volumetric Data)
CT Angiograph can evaluate:
PULMONARY ARTERIES CAROTID ARTERIES PERIPHERAL VASCULAR SYSTEM CIRCLE OF WILLIS
CT- Guided interventional Radiology
use images to guide procedures that would normally require surgery
MULTIDETECTOR (64 SLICE) SCANNERS SUB-MM SLICE THICKNESS EKG GATING
CORONARY ARTERY CALCIUM SCORING CORONARY ARTERY CTA
Coronary artery Calcification Scoring
Amount of Calcium in the coronary arteries is proportional to the overalll amount of atherosclerotic plaque.
Quantitative measure of this
calcium gives an assessment of risk for significant stenosis
Does NOT directly measure the degree of stenosis. NO evaluation of cardiac function.