Transcript File

CONTRAST MEDIUM-1
contrast
The word contrast media means chemical substance sthat due to its high
attenuation of X-ray or differential absorption of X-rays from the
surrounding tissues permit clear demonstration of an organs or
tubular structure .
Types of contrast media :
1. Intravascular :
A. High osmolar-cm or ionic.
B. Low osmolar or nonionic.
2. Oral.
HOCM or ionic:
Sodium iodide and sodium acetrizoate (UROKON) were the first ionic
contrast media. Later various benzoic acid derivatives were introduced
which were combine with Na+ and Meg+
Various HOCM are:
Diatrazoate (urografin)
Iothalmate (Hypaoue)
Metrizoate (Conry)
Iodamide
RCoo
+
Na
I
I
R
R
I
These are monomeric ionic contrast
HOCM or ionic:
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Ionic contrast media are hypertonic with osmolality of 1200-2000 per lit
wich is 4-7 time more than osmolality of plasma.
Almost all the adverse effect of these contrast media are due to hyper
tonicity.
An ideal contrast agent should be :
1.
Non toxic.
2.
Painless to patient.
3.
Low osmolar.
4.
It should not be expensive
The ratio of iodine atoms to ions in HOCM is 3:2
Low Osmolar Nonionic Contrast
• In order to reduce the osmolarity and increase the ratio of iodin atom to
particle in solution dimericionic contrast agent were produced such as
Coo
+ molecules
having 6 iodine atom for two
+ ioxgalate.These compound wereCoo
Na
I
I
+
I
I
Na I
R
MEG
I
I
Dimeric Compound
I
R
(Ioversol)
R
I
Monomeric
nonionic
This Agent is low osmolar but ionic
Iodine 3:1
ROH
I
ROH
I
ROH
I
I
R
I
DIMERIC
NONIONIC
ROH
I
IODINE RITIO
6:1
These Compound are :
1.Iopamidol (Niopam)
2.Iohexol (omnipaque)
3.Iopromide (Ultravist)
4.Ioversol
5 Iotrolon(isovist) 6 .Iodoxinal
These agent have low osmolality as compared to HOMC and fewer side effect.
The only disadvantage is there cost these agent are very expensive.
Clinical Applcation
Urinary system:
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IVU \ EU.
Ascending Uretnrography.
Cystography.
Micturating cystouretnorography.
Antegraded Retbograde Pyeldgraph.
Biliary system:
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Intravenous cholangiography.
T .Tube cholangiography.
P.T.C
E.R.C.P
Clinical Applcation
Cardiovascular system :
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Arteriography.
Venography.
Angiocardiography.
Contrast enhanced CT .
Contrast enhanced M.R.I .
Minor Reaction / Effect
Moderate adverse effects :
 Maintain I / v line
 Antihistamine 10-20 mg paeds 2 mg / kg body wite
Wheeze :
Hydrocortisone 100 I / V , O2 therapy.
Hypotension with bradycardia O2 , I / V Flaid
Atropine 0.6 mg repeat sm total 3 mg.
Contrast Media Used In M.R.I
It enhanced the inherent tissue contrast causes T1 and T2 shortening .
Type :
A. Paramagnetic
EX : Gadolinium D.TPA. Causes T1 shortening signal appear bright.
B. Super paramagnetic
EX : Iron oxide manganese for causes T2 shortening signal appear
dark .
Adverse Reactions
1. Minor :
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Nausea
Vomiting
Sneezing
Urticaria
Pain in arm
Sensation of warmness
2. Moderate Reactions :
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Persistant headache
Severe urticaria and bronchospasm
Wheezes abdominal cramps
Hypotension with bradycardia…………
Severe vomiting G
Adverse Reactions
3. Severe and life threatening
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Laryngeal edema
Angioneurotic edema
Hypotension with tachycardia
Anaphylaxis (2nd) severe
Seizure
Cardiac arrest
Pulmonary edema
Unconciousness / no response / pulse less /cardiopulmonary collapse and
death
Mechanism of contrast media reactions:
1:Over dose
2:Anxiety
3:Chemotoxicity
4:Endothelial damage
5:Release of histamine and other enzymes
6:Anaphylaxis.
Risky group of patients to whom
HOCM is not recommended.
Extreme age eg infants and old people
Hypertension
DM
Asthma
Renal failure
Liver failure
Multiple myeloma
Dehydration
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MRI contrast media
Generally two type of MRI contrast agents
Paramagnetic. Eg Gadolinium and
mangnese agents
Gadolinium ion is a paramagnetic agent
which has 7 unpaired electrons
It is chelated with DTPA because GAD
alone is toxic.It cause T1 shortening due
to that T1 weighted image appear
bright.Different agents in this group are
Gadopentate and Gadodamide.These
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MRI cont,
The second group are Superparamagnetic
Iron oxide.This agent is specifically used
for liver and mainly cause T2
shortening.This has opposing effect and
the enhanced area appear black.
Adverse effect of MRI contrast
Metalic taste in mouth
Nausea vomitting
Itchin
Nephrogenic fibrosis
Urticaria etc
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Indication of MRI contrast
CNS tumors
Crdiac imaging
Vascular imaging
Musculoskeletal imaging
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Ultrasound Contrast agents
Small microbulles
Leovist.Most commonly used
Echovist
Albunex
Echogen
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Indication
Vascular US(Doppler) •
Harmonic imaging •
Sonohysterosalphingography •
ORAL contraST AGENT
.IWater soluble.Gastromiro.It is iopamidol
61% w/v
Gastrographine.It is mixture of sodium
and
meglumine diatrozoate 66%w/v
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Indication
Suspected perforation •
LOCM is used if aspiration is a possibility •
Complications are hypovolumia,pulmonary •
edema and allergic reaction
Barium sulphate
Baritop 100
100%w/v
for barium follow
through
E-Z-HD 250%w/v for barium sallow and
barium meal examination.
E-Zpaque 100% w/v for barium follow
through
E-Z paque 60% w/v for small boel enema
Plibar 115% w/v for barium enema.
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Advantages and disadvantages
of barium
Barium has excellent coating of mucosa
as compared to water soluble contrast.
It is cheap
High mortality if leak occure in to the
peritoneal cavity
Make subsequent CT examination difficult
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Complications
Perforation.The escape of barium in to the •
peritoneal cavity is dangerous
Aspiration is harmless •
Intravasation can result in pulmonary emb •
Contrast 2
Pharmacological agents
Pharmacological agents
Hyoscine –N-butyle bromide(Buscopan)
Adult dose 20mg I/V
It inhibit intestinal motility and gastric secretion
Advantages. Immediate action,short duration of
action and it is not expensive
Disadvantages. Blurring of vision,dry
mouth,tachycardia and urinary retention.
Contraindications.close angle
glaucoma,myasthenia gravis,pyloris stenosis etc
glucogon can be used in these situations
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Glucogon
Adult dose. .3—1mg
Childern dose ,5—1microgram/kg
Advantages.more potent smooth muscle
relaxant than glucogan,,short duration of
action and it do not interfer with ttransit
time of bowel
Disadvantages.hypersensetivity teaction is
possible,long onset of action and
expensive
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Contraindication of glucogan
Adrenal tumors.glucogan can cause •
sudden hypertension.if hypertension
occure,phentolamine can be used for
treatment
Endocrine tumors of pancrease •
Contrast 3
Treatment of contrast media
reactions
Emergency drugs used in X-ray
department
Metacloperamide.For sever vomiting and
for fascilitation of barium follow through .
Adrenaline.1:1000 sc or i/m injection.used
in cardiac arrest
Atropine.600micg in 1ml.used for
treatment of vasovagal shock(hypotension
with bradycardia)
Chlorophenirmine.10mg in 1ml.used for
sedation and vomiting
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Drugs
Sodium bicarbonate 200ml.used to prevent or
treat acidosis
Aminophyline.250mg in 10ml.for the
treatment of bronchospasm
Diazepam i/v 10mg.For the sedation and
treatment of convulsion
Hydrocortisone 100mg.In any emergency
condition.
Dopamine.800mg in 5ml.For treatment of
hypotension with tachycardia
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Drugs
Frusemide. For pulmonary edema and
diuresis
Nalaxone.400micg in 1ml.used as antidote
for morphine.
Protamine sulphate.used as antidote for
heparine.
Dextrose5% 50ml.for I/V fluid replacement
Dextrose 50%.as I/V fluid replacement
Normal saline 500ml as fluid replacement.
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Treatment of toxic reaction of
contrast
Angioneurotic edema. I/V line •
I/V hydrocortisone
I/V antihistamine
sc adrenaline
Oxygen
Bronchospasm I/V line
Oxygen
Aminophyline
Hydrocortisone
Severe urticaria.antihistamine or sc adrenaline
Toxic reactions
Hypotension.
Elevation of legs
No improvement and bradycardia,then
give I/v fluid and atropine
If no improvement and tachycardia,then
give I/v fluid or dopamine infusion.
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