Ch5 Iv And Contrast Flashcards
Contrast agent p 4
Compound usually pharmaceutical in nature, which when administered to a patient , may improve the sensitivity and specify clinical diagnoses
Most contrast agents used do what? P 4
Caused perfumed tissues to enhance
Appear brighter on images because attenuated xray beam
Negative contrast agents p 4
Air
Water
Two things negative contrast agents do? P 4
Distend structure
Improve visualization of internal structures
Five contrast media categories p 4
Intravenous Oral Rectal Intrathecal Intraarticulate
Increases the attenuation of X-ray beam and causes enhancement? P 6
Iodine
Intravenous contrast p 6
Injected into bloodstream
Iodine causes what on ct film? P 6
Brighter image
Enhancement p 6
Increased brightness by contrast on ct image
Ionic agents p 6
Break into charged particles in the bloodstream
Non-ionic contrast p 7
Do not divide into charged particles rather entire until excreted by kidneys
Effects how well contrast tolerated p 7
Less an agent breaks down into greater number charged particles , the better tolerated
Osmolality p 7
Concentration of molecular particles in contrast agent
Two iv contrast osmality groups
Low osmolar
High osmolar
Non ionic contrast and osmaliity p 7
Low osmolar category due to lower concentration of particles
Lower the osmolity effects on the patient p 7
Better tolerated by patient
Why need drink lots water both before and after contrast exam? P 7
Hypertonic solutions compared to blood plasma cause movement of water within tissues into vascular space, causing dehydration
Viscosity p 8
Measure of thickness of liquid related to frictional force of molecules of substance as they pass one another
______the contrast the more force required to administer the solution . Therefore , _____ viscosity is better
Thicker
Lower
Kidneys have hard time clearing ____ molecules out blood p8
Large
Minor reactions
Nausea Chills Vomiting Feeling warm Minor hives Metallic taste Itching Shaking Headache Dizziness Sweating
Moderate reactions
Moderate hives Change pulse rate Hypotension/ hypertension Wheezing Bronchospasm/ larygynospasm Facial edema
Two mechanisms of reactions p 8
Chemotoxic reaction
Idiosyncratic
Chemotoxic reaction p 9
Effected by total volume of the agent and rate of injection
Idiosyncratic reaction p9
Reactions not caused by injection rate and type
Ionic, high osmolar contrast has more molecular particles than low osmolar contrast resulting in ? P 10
Osmotic process- draw water from body tissues and cells
____ reduces viscosity of contrast prior to injection
Warming
_____ the viscosity the more force to inject causing injection site pain
Thicker
______injection rates and _____ concentration of contrast have increased reactions
Higher
Higher
Pre medicating patient with before injection? P 12
Antihistamine
Steroid
Minimizing adverse reactions p 13
Read al labels
Know non ionic contrast for diabetics and diseases of liver or kidneys
Low osmolity and low viscosity the better
Warm contrast to body temperature to reduce viscosity
Pre medicate with antihistamine and steroid to recuse idiosyncratic reactions
Precaution p 13
Condition that would warrant medical decision as to whether the benefits of the exam outweigh the risks posed to the patient
Contraindication p 13
Condition that would preclude a patient from having a study performed in a given manner
Extra action contrast agents with these diseases : p 14
Liver Kidney Thyrotoxicosis Myelomatosis Diabetes Multiple myeloma Sickle cell Pheochrmocytoma Hyperthyroidism History of reaction Asthma Hay fever Food allergies Congestive heart disease
Iv contrast to pregnant lady when ? P 14
No other modality can obtain diagnostic info
If the ct would affect the fetus
If ct. can’t wait until after pr egnancy
When to breast feed after ct injection p 14
Safe right after or if mom wants wait 24 hrs
Bun
5-25 mg/dl
Creatinine
0.6-1.7 mg/dl
Gfr
95-120 ml/min/1.73 m2
eGFR
> 60
In healthy adult, How long for 50% of all contrast out blood stream? P 15
2hrs
Normal pt
10-14 sec
Normal ptt
20-40 sec
Normal inr
- 9-1.3
- 0-3.9 for patient on anticoagulant
- 5-3.5 patients with high risk clot formation
Platelet count
150,000/mm3- 400,000/mm3
Why fasting important for injection ? P 16
Perstslsis creates motion
Vomiting
Diabetic or renal insufficiency patients and injection p 17
Low,osmolar
Non ionic
Metformin ( glucophage, glucovance ) acr 3 caogries
No metformin 48hrs after exam
Metformin resumed after Blooodwork is done to confirm kidney function
Patients with renal insufficiency should stop metformin before injection and should be monitored after
Technique used prior intravenous injection p 18
Aseptic technique
Optimum injection enhancement is achieved at higher injection rates of ___-____
5-6 ml/sec
Power piccs are used at injection rates of ________
Up to 5ml/sec
Regular picc lines and injection p 18
Can’t be used for injection
Type gauge needle p19
18-22 gauge
22 gauge needle allows rates up to ?
3 ml /sec
Required for 5/ml
18 gauge needle injection rate
If site hand
Slow injection rates
Most common site for injection p20
Basilic vein in cubital fossa
How distend vein for injection p 20
Apply tourniquet
Have patient pump hand
Slap vein
Apply heat
Signs of extravastion what must be done? P 22
Stop injection
Venous air emboli p 22
Air introduced into vein during injection
Three tissue enhancement phases p 23
Bolus phase
Non equilibrium phase
Equilibrium phase
Bolus phase p 23
Enhanced begins when contrast injected
Significant density difference between abdominal aorta and inferior vena cava
Bolus moves away from heart
Optimal quality cta imaging
Non equilibrium phase p 23
10-30 HU density difference between abdominal aorta and inferior vena cava
Bolus disperses into capillaries then into the veins
Best differentiation in soft structures
Since _______has dual supply , timing of scan is crucial p 24
Liver
Equilibrium phase p 24
Density difference of less than 10 hu between abdominal aorta and inferior vena cava
Concentration in veins becomes similar to concentration in arteries
Hepatic arterial phase p 24
20-40 sec into injection
Portal venous phase p 24
60-90 s into injection
Liver injection phases p 24
Hepatic arterial phase
Portal venous phase
Opacification by oral contrast agents used? P 27
Reduce risk of misdiagnosing fluid filled bowel as abscess or tumor and helps visualize lesion is exterior to the bowel or if it infiltrates the bowel
Oral contrast media p 27
Barium sulfate
Iodinated
Barium used in ct vs conventional radiography ? P 29
Conventional barium too high density causing sever streak artifacts
Barium passes through gi tract without _____? P 29
Being absorbed or metabolized
Adverse reactions barium p 29
Diarrhea Abdominal cramping Barium granuloma Barium appendicitis Intestinal perforation Peritonitis
Contraindications of barium p 30
Colon obstruction
Tracheosopageal fistula
Obstructing lesions of small intestine
Pyloric stenosis
Hypersensitivity to barium sulfate
Barium passes gi tract? P 30
Less than 2 hours
Iodinated oral contrast are more ____ than iv agent
Diluted
When to use iodinated oral agents vs barium? P 30
When contraindicated
How long Iodinated oral contrast passes through gi ? P 31
2 hrs
Post myelographic ct p 34
Elevate head
Confirm density of contrast media
Ensure contrast media does not separate from csf
Intraarticuar exam p 35
Injected into patient joint under fluro
Contrast for head exams p 36
Amount?
Delay?
No?
Dose 100 ml
Scan delay up to 5 mins after injection
No oral contrast
Normally enhanced during contrast ct of the head ? P 36
Blood vessels
Choroid plexus
Dura
Non contrast studies of head show ? P 37
Sininutis, trauma bleed, Graves’ disease, early cerebrovascular events, early subdural hematoma, hydrocephalus, dementia, mastoiditis, labyrinthisis, facial or seventh nerve palsy, hearing loss, perteous and temporal bone
Contrast for neck ct pg 37
Amount
Injection rate
Delay
No?
Dose 100 ml
Injection rate 3 ml / sec
Scan delay 35 sec
No oral contrast
Ct neck with contrast allows differentiation of ? P 37
Blood vessels from lymph nodes and outline epidural venous plexus
Studies used for ct neck with contrast p 38
Neck mass Lymph nodes Parathyroid adenoma Paratoid gland mass Oral pharynx Larynx Brachial plexus
Contrast for chest exam p 38
Dose
Rate
Delay
Dose 100 ml
Injection rate 3 ml/sec
Scan delay 30 sec
No oral contrast
Studies of abdomen require both ____ ? P 39
Oral and iv contrast
Oral contrast abdomen ct helps ? P 39
Opacity gi tract helps decrease risk of mistaking fluid filled bowel for tumor or abscess
Ct abdomen with contrastrSt shows? P 39
Mass
Lesions
Vascular abnormalities
Trauma
Contrast for abdominal exams p 40
Dose 75-150 ml
Injection rate 2-4 ml/s
Scan delay
Liver: 70-80 sec
Pancreas: 50-60 sec
Kidneys: 80-90 sec
Oral contrast used
Biphasic liver study p 41
Used to perform differentiate liver lesions with arterial blood supply And those with venous blood supply
Cta study used for ? P 43
Evaluation of arteries and vessels
Why a cta exam? P 43
Narrowing by atherosclerosis
Anuerysms
Dissections
Traumatic injury
Congenital vascular anomolies
Effects of vascular treatment
Cta injection rate ? P 44
3-5 ml/sec
For cta exam, thin slices collected _______ direction of blood flow ? P 44
Same direction
Cta exams increasing the _____ scans vessels faster p 45
Pitch
Reconstruction of slices in cta p 45
With overlap which increases resolution
