Presentation on theme: "CONTRAST MEDIUM-1. contrast The word contrast media means chemical substance sthat due to its high attenuation of X-ray or differential absorption of."— Presentation transcript:
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 These are monomeric ionic contrast RCoo I I I R R + Na
Ionic contrast media are hypertonic with osmolality of 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 HOCM or ionic:
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 ioxgalate.These compound were having 6 iodine atom for two molecules Coo I I I I I I R + Na + MEG Dimeric Compound This Agent is low osmolar but ionic Coo I I I R R + Na Monomeric nonionic Iodine 3:1 (Ioversol)
ROH I I I I I I R DIMERIC NONIONIC 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.
Minor Reaction / Effect Moderate adverse effects : Maintain I / v line Antihistamine 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 : Nausea Vomiting Sneezing Urticaria Pain in arm Sensation of warmness 2. Moderate Reactions : Persistant headache Severe urticaria and bronchospasm Wheezes abdominal cramps Hypotension with bradycardia………… Severe vomiting G
3. Severe and life threatening Laryngeal edema Angioneurotic edema Hypotension with tachycardia Anaphylaxis (2nd) severe Seizure Cardiac arrest Pulmonary edema Unconciousness / no response / pulse less /cardiopulmonary collapse and death Adverse Reactions
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
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 compound are injected by I/v route
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
ORAL contraST AGENT.IWater soluble.Gastromiro.It is iopamidol 61% w/v Gastrographine.It is mixture of sodium and meglumine diatrozoate 66%w/v
Indication Suspected perforation LOCM is used if aspiration is a possibility Complications are hypovolumia,pulmonary edema and allergic reaction
Barium sulphate Baritop %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.
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
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
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
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
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
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
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.
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.