CONTRAST MEDIA Dr. Ahmed Refaey FRCR

Types of contrast media * Iodinated : * HOCM * LOCM * GIT contrast agents * Barium sulphate * water soluble contrast media ( Gastrographin) * MRI contrast agent * Ultrasound contrast agent

IODINATED CONTRAST AGENTS

Classification High osmolar contrast agents ( HOCA ) Low osmolar contrast agents ( LOCA ) * Ionic * Non-ionic

HOCM HOCA are in use since the 1950. * Urovist. * Urogarfin * Angiovist. * Conray. * Renografin. * Renovist. * Hypaque.

LOCA Non-ionic Ionic Ultravist Omnipaque Visipaue Oxilan Hexabrix

LOCA have a lower incidence of adverse reactions by a factor of 6 for all reactions , and by a factor of 9 for the severe reactions.

Toxic effects Vascular toxicity Soft tissue toxicity Cardiovascular toxicity Haematological changes Thyroid function Nephrotoxicity

Nephrotoxicity Incidence of contrast induced nephrotoxicity 5% In the majority, renal impairment is temporary Predisposing factors : * impairment of renal function * DM * dehydration * old age * large doses of CM * multiple myeloma

Reactions of CM Fatal reactions ( death ) -1/140,000 for HOCM 1/300,000 for LOCM -occur in minutes -old age -causes ( cardiac arrest – pulmonary edema – respiratory arrest – coagulopathy – laryngeal edema- bronchospasm )

Non- fatal reactions 1-flushing, metallic taste in the mouth, nausea, sneezing, cough—common & related to dose and speed of injection. 2- urticaria 3- angioneurotic edema 4- bronchospasm 5- pulmonary edema 6- arrythmia 7- hypotension 8- delayed reactions: rashes , headaches, itching

*Excluding death, adverse reactions can be classified in terms of severity as: 1- major reactions : those that interfere with the examination and require treatment. 2- intermediate reactions : those that interfere with the examination but do not require treatment. 3- minor reactions : those that do not interfere with the examination and require only assurance

Risk factors allergy , asthma Cardiac disease Hepatic failure Poor hydration Co-administration of: glucophage Previous reaction to contrast media - HOCM----- 20% - LOCM ----- 5 % Other factors: * pheochromocytoma * sickle cell disease * hyperprotinemia ( multiple myeloma )

High risk patients should either: 1 – be premeicated with steroids 2- to be evaluated with other modality ( U/S – MRI )

Route of administration : intravenous Uses : * CT study * urography ( IVP- urethrography_ cystography ) * angiography ( arteriography – venography ) * PTC, ERCP, T-tube cholangiography * hystrosalpingography * sialography * fistulography

Urography

IVU

Cystogram

Urethrogram

Angiography

Sialogram

Sialogram

Fistulogram

PTC

PTC

ERCP

T-tube cholangiogram

HSG

HSG

GIT contrast agents

Gastrointestinal contrast agents BARIUM SULPHATE WATER SOLUBLE CONTRAST MEDIUM (GASTROGRAFIN )

BARIUM SULPHATE

Barium sulphate Thin barium : for upper GI studies, small bowel follow through, barium enema ---- 40% BaSO4 solution. Thick barium : for double contrast studies ---- 85% BaSO4 solution

Advantages : * excellent coating, allowing the demonstration of normal and abnormal mucosal patterns. * cost

Complications: Exacerbation of GI obstruction above a preexisting bowel obstruction Intraperitoneal extravasation through gut perforation results in extensive fibrosis

Contraindication : Bowel obstruction Bowel perforation

Water soluble contrast medium (gastrografin )

Water soluble contrast medium (Gastrografin ) Oral contrast medium for opacification of GIT Hygroscopic agent Undiluted or diluted Can be used as a substitute for barium if GI perforation is suspected. In CT , diluted by 1:40

Complications Aspiration can cause chemical pneumonitis Diarrhea Hypovolemic shock if used undiluted

CT contrast agents IV contrast medium Oral water soluble contrast medium (gastrografin)

MRI contrast agent

MRI contrast agent Gadolinium Gd-DTPA IV

ULTRASOUND CONTRAST AGENT Levovist / echovist IV

Thank you

All agents consist of radiodense iodinated Benzene ring. Ionic agent typically formulated as Sodium and or meglumine salts.