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Contrast Media Ch 19
Contrast Media and Special Radiographic Techniques
| Question | Answer |
|---|---|
| Negative Contrasts | appear black absorbs less radiation than surrounding tissues air & gases |
| Where air and gas contrast media used | GI tract arthrography, myelography, female reproductive system, biliary system. |
| Iodinated Media | heavy element, positive contrast, appears white, absorbs more radiation than surrounding tissues. |
| Water Soluble Iodinated Compounds | carbon based organic chemicals composed of molecules containing iodine atoms and combos of other atoms. |
| How water soluble iodinated compounds can be administered | orally, vaginally, itravenously, intrarterially |
| How water soluble iodinated compounds are characterized | concentration, osmolality, viscosity, toxicity |
| Iodine concentration | determines the degree of xray attenuation |
| high concentrations of iodine = | greater viscosity, osmolality and greater toxicity |
| iodine osmolality | the number of particles in solution per kg of water |
| osmolality of human blood | 300 milliosmoles per kg |
| osmolality of water soluble iodinated contrast | 300-1000 milliosmoles/kg |
| ionic media | the molecules within the contrast media dissociate into two charged particles when placed in solution |
| non ionic media | molecules remain whole in the solution |
| 1.5 - 3.2 | 3 iodine- dissociate 2 particles. Ionic. Creates other reactions within patient |
| 3- 3.1 | 3 iodine. Does not dissociate. Nonionic. Safer for patients. |
| HOCA | high osmolality contrast agents |
| LOCA | low osmolality contrast agents |
| viscosity | a measure of resistance of a fluid to flow |
| determines viscosity | the # of particles in the solution size of particles in solution attractions among the particles specific nature of the particles in the solution |
| toxicity | how harmful it is to the body |
| toxicity determined by | chemical configuration iodine concentration osmolality ionization characteristics rate of injection dosage |
| lowest toxicity factors | nonionic, low osmolality, low iodine concentration, slow injection rate. |
| Reactions due to osmolality | dehydration of surrounding blood cells & tissues increase in pulmonary artery pressure increase in blood volume increase in cardiac output |
| reactions due to ionization | seizure of cardiac dysfunction sense of warmth in pelvis lightheadedness N/V anaphylactic responses |
| reactions due to molecular toxicity | excessive dose, renal insufficiency, medication incompatibility, |
| BUN ranges | 6 - 20 mg/dL |
| Creatinine Ranges | .6 - 1.5 mg/dL |
| History to get for iodinated contrast media | age, allergies, history of asthma, routine meds, vital signs, BUN/creatinine levels. Diabetes, heart disease. |
| Allergic reactions to contrast media | restlessness and sense of apprehension increased HR weakness/pallor cool, clammy skin itching/rash throat constriction dyspnea drop in BP greater than 30 mm/Hg below baseline systolic pressure |
| Expected side effects from contrast media | metallic taste warmth in the body |
| Excretory urography IVP/IVU | functional exam of the urinary system through IV injection of contrast |
| Nephrogram | blush film when kidneys are beginning to fill with contrast. |
| Cystography | exam of the internal contours of the bladder and the urethra through retrograde injection of contrast. |
| Retrograde urography | exam of the ureters and kidneys through retrograde injection of contrast. |
| myelographyam | exam to visualize internal structures of the spinal canal, through intrathecal injection. |
| contrast arthrography | exam to visualize joints to detect disease or injury through the direct injection of contrast. |