Overview: Radiography + Med. Imaging Flashcards
Radiology Principles (3)
- Based on ability of x-rays to penetrate tissues and organ
- Rate of penetration depends on organ/tissue density - Greater density = opaque image - Lesser density = transparant image
- All radiation studies involve some exposure to harmful radiation, choose scans wisely
Radiography presentations of body structures (5)
- Healthy bones = white
- Bone fx = radiolucent line
- Osteoporotic bone = gray/porus
- Healthy lung/bowel = black
- Other structures (musc/bld/organ/misc tissues) = black
Radiography views (3)
- AP = x-rays pass front → back
- PA = x-rays pass back → front
- Oblique = x-rays pass @ angle
Types of radiography studies (3)
- Plain films
- Fuoroscopy
- CT scan
Define Fluoroscopy
- Fluoroscope used to visually examine target
- Utilizes the following tools:
- X-ray source
- Fluorsecent screen
- More radiation exposure than plain film
- Allows for real time images
Define CT Scan
- Integrated view of multi-angled x-rays
- Each x-ray represents a “slice,” selection of tissue @ specific level
- Variation of density allows for variable penetration
- Permits exam. of tissue that would otherwise obscure due to surroundings
- Presents with various shades of black/gray on images
Plain x-ray indications (5)
Suspision of the following:
- Trauma/injury
- Infection
- Tumor
- Arthritis
- Bone spurs
Spinal x-ray indications (5)
Suspicion of the following
- Trauma
- Degenerative changes
- Tumor mets
- Spondylollithesis
- Scoliosis
Define Spondylolithesis
Slipage of 1 vertebral disc over another, causing vertebral column dysfunction
Chest x-ray Indications (5 structures, 8 general conditions)
Evaluate…
- Heart
- Lungs
- Bony thorax
- Mediastinum
- Great vessels
For these conditions
- Tumors
- Infections
- Pleural fluid
- Pulmonary edema
- COPD
- Pneumothorax
- Rib fx
- Thoracic vert. fx
General Kidney, Ureter, Bladder x-ray (KUB) Indications (3)
- Intestinal obstruction
- Soft tissue masses
- Ruptured viscus
Note: **Often the most cost effective measure for ruling in GI/GU pathology
Abdominal CT Indications (3 general, 1 c 8 common examples)
- CT-guided needle biopsy
- Diagnosing/staging neoplasms
- Monitor and diagnose abdo disease
- Abcess
- Inflammation
- Perforated bowel
- Intestional obstruction
- Calculi
- Tumors (adrenal, liver, pancras)
- Pseudocysts
- Trauma (esp. splenic hematoma)
Brain CT Indications (7)
Diagnosis of the following
- Brain tumor
- Cerebral infarction
- Ventricular displacement/enlargement
- Cortical atrophy
- Bleeding/AV malformation
- Hematoma
- MS
Chest CT Indications (6)
Aid in the diagnosis of the following pathologies, esp when CXR dues not suffice
- Tumor
- Nodule
- Abcess
- Pleural effusion
- Enlarged lymph nodes (often in the presence of lung and mediastinum dysfunction)
- Pulmonary embolism (via spiral CT)
Spiral CT (definition, 2 major uses)
Definition: CT scan technique involving continuous movement of pt through the CT scanner. Allows faster scanning c incrased definition of internal structures
Uses: Visualization of the following
- Blood vessels
- Internal tissues
Ulrasound Principles (3)
- High frequency sound waves directed @ internal body structures
- Recording of impulse intensity reflects back through tissues
- Differentiates b/w acoustic densities of solid and cystic structures, thus readily used for discerning cyst vs tumor
Ultrasound Advantages (3)
- Noninvasive
- No ionizing radiation
- Less expensive than CT or MRI
Ultrasound Procedure (5 steps)
- Skin overlaying indicated area coated c lubricating gel
- Sonographer specifically directs probe (as transducer) at angles corresonding with structure of interest
- Transducer emits directed sound waves at tissue
- Echos converted received by probe (as receiver) convert to electrical images that are displayed visually on a screen
Types of US orders (8)
- Abdominal
- Breast
- OB
- Pelvic
- Prostate
- Scrotal
- Transesophageal Ecocardiogram (TEE)
- Transthoracic Ecocardiogram (TTE)
Abdominal US Uses (5 organs, 6/1/4/2/4 pathologies)
- Kidney
- Cyst
- Tumor
- Calculi
- Hydronephrosis
- Abcess
- Ectopic kidney
- Abdominal Aorta
- Aneurysm (most cost effective for minor AAA)
- Liver
- Cyst
- Abscess
- Dilated hepatic duct
- Tumor
- Gallbladder
- Gallstones
- Polyps
- Pancreas
- Tumor
- Pseudocyst
- Inflammation
- Abscess
Breast US Uses (4)
- Differentiate b/w cystic and solid lesions
- Identify BC masses too dense for accurate mammography
- Monitor cyst progression/regressino
- Evaluation in conjunction c mammogram
OB US uses (2 categories, 8/3 specifics)
- Pregnancy
- Early confirmation/diagnosis of pregnancy
- ID multiples
- Differentiate normal pregnancy from hydatiform mole
- Determine fetal age (from head diameter)
- Measure fetal growth
- ID placental abnormalities
- Determine fetal position
- Diagnose ectopic pregnancy
- Pathology
- Neoplasm
- Cyst
- Abscess
Pelvic US Uses (7)
Aid in the diagnosis of the following:
- Ovarian cyst
- Ovarian tumor
- Tubo-ovarian abscess
- Uterine fibroid
- Uterine cancer
- Pelvic Inflammatory Disease (PID)
- Endometrial thickness
Prostate/Rectal US Uses (3)
- Evaluate pts with elevated prostatic surface antigen (PSA)
- Evaluate prostate size/contour/consistency
- Diagnose prostate cancer in the context of the following
- Positive digital rectal exam (DRE)
- Elevated PSA
Scrotal US Uses (7)
- Eval. scrotal mass
- Eval. scrotal trauma
- Eval. scrotal pn
- Measure testicular size
- Eval. testicular neoplasm
- Survey pt c previous primary or metastatic testicular tumor
- Localize undescended testicle
Transesophageal Echocardiograpm, TEE
(Procedure, General Use, Advantage)
Use: Provide info about heart muscle, valves, and general function
Procedure: Endoscopically place transducer in distal esophagus or proximal stomach to transmit sound waves closer to target heart tissue
Advantages: Proximity allows for better resolution than typical or TTE US techniques
TEE Uses (6)
- Mitral valve visualization
- Differentiate b/w intracardiac and extra cardiac masses
- Atrial septum visualization (for ASD)
- Diagnose thoracic aortic dissection
- Detect valvular vegetation indicative or endocarditis
- Determine cardiac sources of arterial emboli
Transthoracic Echocardioagram, TEE Uses (4)
- Evaluate heart wall motion
- Detect valvular disease (but not as well as TEE)
- Evaluate heart during stress testing
- Identify and quantify pericardial fluid
MRI Advantages (2)
- No exposure to ionizing radiation
- Comparatively high level of contrast b/w normal and pathologic tissue
MRI MOA
MRI sends radiofrequencies into tissues which changes the magnetic field. Machine measures distrubance/behavior of H+ atoms when exposed to this change in magnetic field
MRI Uses (5)
Evlauate the following tissues with higher specificity than other scans
- CNS
- Spinal cord
- Brain (for tumor)
- Bony spine
- Joints
- Extremities
- Breast (more sensitive than mammography or US)
MOA: Positron Emission Tomography, PET Scan
- Admin radioactive versions of endogenous chemicals
- Target organ emits positrons, which are detected by the machine
- CT images convert positrons into high resolution 3D image
Result: Highlight metabolically active tissues, thus viewing both anatomy **and **physiology (shows flow of positrons thru tissue)
PET Scan indications (3 general)
Visualize structures with rapid blood flow:
- Brain
- Heart
- Tumors
