CONTRAST MEDIUM1 contrast The word contrast media means

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: • • 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 were. Coo 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 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: Ø Ø Ø IVU EU. Ascending Uretnrography. Cystography. Micturating cystouretnorography. Antegraded Retbograde Pyeldgraph. Biliary system: Ø Ø Intravenous cholangiography. T. Tube cholangiography. P. T. C E. R. C. P

Clinical Applcation Cardiovascular system : Ø Ø Ø 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 , O 2 therapy. Hypotension with bradycardia O 2 , 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 T 1 and T 2 shortening. Type : A. Paramagnetic EX : Gadolinium D. TPA. Causes T 1 shortening signal appear bright. B. Super paramagnetic EX : Iron oxide manganese for causes T 2 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

Adverse Reactions 3. Severe and life threatening § § § § Laryngeal edema Angioneurotic edema Hypotension with tachycardia Anaphylaxis (2 nd) 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 • •

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 T 1 shortening due to that T 1 weighted image appear bright. Different agents in this group are Gadopentate and Gadodamide. These • •

, MRI cont The second group are Superparamagnetic Iron oxide. This agent is specifically used for liver and mainly cause T 2 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 • • •

Indication of MRI contrast CNS tumors Crdiac imaging Vascular imaging Musculoskeletal imaging • •

Ultrasound Contrast agents Small microbulles Leovist. Most commonly used Echovist Albunex Echogen • • •

Indication (Vascular US(Doppler • Harmonic imaging • Sonohysterosalphingography •

ORAL contra. ST 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 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 • • •

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

Pharmacological agents Hyoscine –N-butyle bromide(Buscopan) Adult dose 20 mg 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— 1 mg Childern dose , 5— 1 microgram/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 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. 600 micg in 1 ml. used for treatment of vasovagal shock(hypotension with bradycardia) Chlorophenirmine. 10 mg in 1 ml. used for sedation and vomiting • •

Drugs Sodium bicarbonate 200 ml. used to prevent or treat acidosis Aminophyline. 250 mg in 10 ml. for the treatment of bronchospasm Diazepam i/v 10 mg. For the sedation and treatment of convulsion Hydrocortisone 100 mg. In any emergency condition. Dopamine. 800 mg in 5 ml. For treatment of hypotension with tachycardia • • •

Drugs Frusemide. For pulmonary edema and diuresis Nalaxone. 400 micg in 1 ml. used as antidote. for morphine Protamine sulphate. used as antidote for. heparine Dextrose 5% 50 ml. for I/V fluid replacement Dextrose 50%. as I/V fluid replacement. Normal saline 500 ml 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 • •