Definition of RADIOPAQUE
-not allowing the passage of x-rays (more white, metal)
Definition of RADIOLUCENT
-allow passage of x-rays (more black, air)
X-RAY (plain films)
- how it works
- advantages/disadvantages
- indications
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
how work:
- photons, shorter the wavelength=greater energy
- source, detector, camera
Advantages: see bones
Disadvantages: exposure to radiation
CI:??
Contrast: generally no, but special circumstance
Radiation: chest: 10mRem Abd: 70mRem
-Used to diagnose CXR, KUB, skeletal films, dental films, plain abd films
Attenuation Def
x-ray radiation is absorbed and attenuated (weakened) as it passes through diff tissues.
- greater the density of tissue= greater absorption of xray»>less clear image (less energy gets to film to produce picture)
Factors affecting image quality of XRAY
motion, thickness of body part, scatter, magnification, distortion ( image not lined up with film)
Heart Looks larger on PA or AP?
AP
Which produces better films, AP or PA?
PA!!!!!!
FLOUROSCOPY
- how it works
- advantages/disadvantages
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
- examples of use
Works: real time/moving XRAY, image recorded and played back
Advantage: live images, can be played back, allows you to see its functionality
Disadvantage: need for barium in body
CI- barium may be aspirated into lungs causing pneuomonitis,
Contrast: yes; barium
radiation: yes
Used to diagnose: cancers of head, tumors, hiatal hernia, structural problems, muscle disorders, strictures, GERD
Used for: GI barium swallow studies, draning abcesses, angiography
UPPER GI SERIES & UGI w/ BOWEL FOLLOW THROUGH
- how it works
- advantages/disadvantages
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
Works: x-ray examination of esophogus, stomach, and duodenum
-multiple xrays taken to see how well contrast moves throughout the upper GI.
Advantage: follow contrast w/ limited radiation exposure
Disadvantage: some radiation exposure, requires contrast
Contrast: yes
Radiation: 600mREM
Used to diagnose:
-ulcers, GERD, inflamm, tumor, polyp, diverticula, dysphagia, motility disorders, strictures
CT/CAT SCAN
- how it works
- advantages/disadvantages
- indications
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
work: computer assisted tomography, uses xrays to create cross-sectional pictures of the body
* Smaller distance between slices= better detail though significant amount of more radiation
Advantage:
- useful for eval of soft tissue and bone
- xray generates 3D image
- cheaper than MRI
- can image any body part
- can perform CT angiography
Disadvantages: more radiation than one x-ray
CI: iodinated (IV)(renal failure) and barium contrast (oral)(allergy)
Contrast: yes (2 types)
Degree of radiation: Chest: 700mRem
Used to diagnose: soft tissue/bone/organs
MRI
- how it works
- advantages/disadvantages
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
Magnetic Resonance Imaging
Works; magnetic field using pulses of radio-wave energy to make pictures of organs and structures
advantage: no radiation, BEST for soft tissue, contrast is not iodine based- well tolerated
Disadvantage: -contrast may cause worsening renal failure, cannot have recent metal in body
-side effects of contrast (warm and pee pants)
CI: renal issues; wouldnt be able to take contrast
Contrast: yes, may be used.
Radiation: none
Used to diagnose: soft tissue; brain, spinal cord, muscles, tendons, ligaments
ULTRASOUND
- how it works
- advantages/disadvantages
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
Works: transducer converts electrical energy into a brief pulse of high frequency sound energy that is transmitted into patient tissues. Transducer then becomes receiver that detects sound echos reflected from tissues.
Advantages:
- Image virtually any part of the body.
- no radiation
- noninvasive
- contrast can be used in special circumstances (cardiac)
Disadvantages:
-technology limited by fat and air
Radiation exposure: none
Used to diagnose: cancer, cyst, gall stone, babies, cardiac, etc.
Hyperechoic
White spots (bone and dense tissue). Increased amplitude of ultrasound waves returned.
Hypoechoic
Dark spots (air, fluid, less dense tissue). Decreased amplitude of ultrasound waves returned.
DOPPLAR ULTRASOUND
- how it works
- examples of use
works: uses reflected sound waves to evaluate blood as it flows through blood vessel
Helpful for determining clots, plaque, stenosis
NUCLEAR IMAGING
- how it works
- used for
- radiation
Work: uses isotope in body, isotope emits gamma rays to camera and produces image
Radiation: study dependent
Cardiac: 4070mRem
Bone Scan: 630mRem
Used for: bone scan,PET scan, MUGA, myocardial perfusion scan,
PET SCAN
- how it works
- advantages/disadvantage
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
Positron Emission Tomography
Work: isotope goes to areas that are metabolically active,
produces 3d image of functional processes.
Advantages: able to evaluate cancer or remission of cancer
Disadvantages:$$$
Contrast: no
Radiation: variable
Used to diagnose:
-cancer
ANGIOGRAPHY
- how it works
- advantages/disadvantages
- CI
- Contrast yes/no?
- degree of radiation exposure
- Used to diagnose______.
Works: obtained using flouroscopy
Advantages: can be obtained via CT, MRI, and flouroscopy
Disadvantage:Invasive
CI:risk of thrombosis, dissection, bleeding, sedated, contrast allergy/ life threatening rxn, renal failure
Contrast: IV contrast
Radiation: involved in all except MRI angio
Used to diagnose: imaging blood vessels
Tissue Densities XRAY
White–>Black
metal, bone, blood, liver(middle of spectrum), lung, fat, air
T1/T2 Weighted image Color Scales
T1
CSF calcium grey matter, white matter, fat;bone marrow; melanin
——————————————–
bone;fat, white matter, grey matter, csf, brain edema;water
T2
Black—> White
* Grey matter is same for both
view slide 51
- CSF darker on T1
- White matter darker on T2
- Fat is darker on T2
What does the white tissue look like in a Scan of skull/brain
MRI
CT
MRI- thin fat
CT- thick bone
