Alternative Imaging Flashcards
Echogenicity
Gray scale for ultrasounds
* hyperechoic = lighter than surrounding
* hypoechoic = darker than surrounding
* anechoic = black (fluid)
* isoechoic = uniform
Echogenicity of Tissue
Hypo to Hyper
- Blood vessels
- Bladder
- Kidney
- Liver
- Prostate
- Spleen
Near Field vs Far Field
Distance of image from probe
* near = closer, oriented at top of screen
* far = farther, oriented at bottom of screen
Sagittal Imaging Plane
Probe oriented cranial to caudal
* cranial on the left side of screen
* move left to right
Transverse Imaging Plane
Probe oriented right to left
* patient’s right side is on the left of the screen
* move cranial to caudal
Resolution
Ability to distinguish separate structures and provide image details
* image resolution depends on frequency
* higher frequency = shorter wavelength and better resolution
Frequency vs Penetration
Higher frequency gives better resolution, but less penetration power
Artifact
Acoustic Shadowing
* beam is reflected or absorbed at interface
* no sound wave penetration - black shadow appears
* see with bone, gas, feces, or FB
Artifact
Formed through transmission and far-field enhancement
* beam weakens when passing through fluid
* far side of fluid area is more intense than surrounding
Artifact
Reverberation
* beam bounces back and forth between gas and probe
* creates evenly spaced parallel white lines
Artifact
Mirror Image
* beam his large curvilinear structure
* see along diaphragm-liver border
Fluoroscopy
Gives real-time imaging of structures
* mainly used to view GI tract
* high kV and low mA
CT or CAT
Computed Tomography
* shows details in structures and tissues of certain planes while ignoring those of others
* one of the most expensive tests
* used to examine CNS and PNS
* gives anatomy information only
MRI
Magnetic Resonance Imaging
* similar to CT
* no harmful radiation emitted
* used for head and spinal exam
* gives anatomy and function information
