CONTRAST MEDIACONTRAST MEDIA

By Jayanti GyawaliBy Jayanti GyawaliB.Sc.MIT 3B.Sc.MIT 3rdrd batch batch

22ndnd year year

It is an agent that changes differential attenuation of x-ray by increasing or decreasing the density of the structure.

It is commonly used to enhance the visibility of blood vessels, gastrointestinal tract etc.

CONTRAST

MEDIA

Types of Contrast Media

Positive contrast media.Negative contrast media.(air

/carbon dioxide)Paramagnetic contrast media

(MRI)Ultrasonic contrast media(USG)

Positive ContrastPositive Contrast

Substance absorbs x rays

Organ become radiopaque

Most common media I,Ba

Negative ContrastNegative Contrast

Organs become more Organs become more radiolucent.radiolucent.

X-rays penetrate more X-rays penetrate more easily.easily.

Ex: air,CO2Ex: air,CO2

Oil based C.M.Oil based C.M.

a)a) It was 1It was 1stst introduced in myelography by introduced in myelography by sicard as 1sicard as 1stst generation C.M in 1921. generation C.M in 1921.

b)b) it was used for bronchography, HSG, it was used for bronchography, HSG, pyelography and lymphography.pyelography and lymphography.

c)c) It is rarely used now a days in some special It is rarely used now a days in some special cases like COPD & pulmonary cases like COPD & pulmonary hypertension.hypertension.

Disadvantages of Oil Based Disadvantages of Oil Based C.MC.M..

Poorly absorbed so forms foreign body Poorly absorbed so forms foreign body granulomata.granulomata.

Pulmonary and peripheral fat micro Pulmonary and peripheral fat micro emboli.emboli.

They are water soluble C.M They are water soluble C.M

It is of two types-It is of two types-a.a. Renal C.M Renal C.M

b.b. Biliary C.MBiliary C.M

2nd generation C.M

Iodine is main + ve C.M and used as 25% NaI in 1923.

In 1925,pyridine series developed as-• uroselectant A(1 iodine atom)• uroselectant B(2 iodine atom)

This diodinated C.M were used in diagnostic radiology with satisfactory tolerability.

Renal C.M

In 1950, 3 changes were made in pyridine derivatives.

Changed to Benzene with 3 iodines. Hydrophillic side chains were added. Meglumine cation was introduced.

Renal C.M Contd…..

WHY IODINE?WHY IODINE?

IODINE(atomic wt 127) provides IODINE(atomic wt 127) provides excellent radio-opacity due toexcellent radio-opacity due to

Higher atomic no: and K-shell Higher atomic no: and K-shell electron binding energy of 34kev electron binding energy of 34kev which is lower than but closed to which is lower than but closed to mean energy used in diagnostic x-mean energy used in diagnostic x-rays and thus maximizing the photo-rays and thus maximizing the photo-electric effect. electric effect.

Iodinated Contrast Iodinated Contrast AgentsAgents

Principal classes of iodinated Principal classes of iodinated radiological contrast mediumradiological contrast medium

1). CONVENTIONAL HOCM 1). CONVENTIONAL HOCM Ionic monomerIonic monomer

2). LOCM2). LOCM Ionic dimerIonic dimer Non ionic monomerNon ionic monomer Non ionic dimerNon ionic dimer

CONVENTIONAL HOCMCONVENTIONAL HOCMIonic monomerIonic monomer

Ionic MonomerIonic Monomer

Acetrizoate (Diaginol, Urokon)Acetrizoate (Diaginol, Urokon) Diatrizoate (Angiografin, Hypaque, Diatrizoate (Angiografin, Hypaque,

Renografin, Urografin, Urovison)Renografin, Urografin, Urovison) Iodamide (Uromiro)Iodamide (Uromiro) Ioglicate (Rayvist)Ioglicate (Rayvist) Iothalamate (Conray)Iothalamate (Conray) Ioxithalamate (Telebrix)Ioxithalamate (Telebrix) Metrizoate (Isopaque, Triosil)Metrizoate (Isopaque, Triosil)

Iodinated Contrast Iodinated Contrast AgentsAgents

IONIC MONOMERSIONIC MONOMERS

Tri-iodinated benzoic acid derivative Tri-iodinated benzoic acid derivative with Na+ / meglumine cationwith Na+ / meglumine cation

High osmolality > 1400 mosm/kgHigh osmolality > 1400 mosm/kg Iodine:particle ratio of 3:2Iodine:particle ratio of 3:2

Further classified on basis of % of Further classified on basis of % of compound in the solution.eg. 30%, compound in the solution.eg. 30%, 70%[ UROGRAFFIN 76%]70%[ UROGRAFFIN 76%]

Sodium is toxic to endothelium & Sodium is toxic to endothelium & BBB So avoided in venography and BBB So avoided in venography and cerebral angiography.cerebral angiography.

Ionic MonomerIonic Monomer

Ionic MonomerIonic Monomer

Meglumine salts are used for this.Meglumine salts are used for this. Both pure sodium and pure Both pure sodium and pure

meglumine salts are associated with meglumine salts are associated with high risk of ventricular fibrillation so high risk of ventricular fibrillation so a mixture of sodium and meglumine a mixture of sodium and meglumine is used.is used.

LOCM CONTRAST MEDIALOCM CONTRAST MEDIAIONIC DIMERSIONIC DIMERS

Ionic dimer Ionic dimer Two tri-iodinated benzene rings with single Two tri-iodinated benzene rings with single carboxyl other replaced by non-ionizing side carboxyl other replaced by non-ionizing side group.group.Iodine: particle ratio of 6:2Iodine: particle ratio of 6:2Low osmolality 600 mosm/kgLow osmolality 600 mosm/kgExamples: loxaglate{Examples: loxaglate{HEXABRIXHEXABRIX}}

LOCM Iodinated Contrast LOCM Iodinated Contrast AgentsAgents

Ionic dimersIonic dimers

Hexabrix is acceptable arteriographic Hexabrix is acceptable arteriographic agent with reduced pain but on i.v agent with reduced pain but on i.v shows toxicity so not to be used in shows toxicity so not to be used in IVU,and CT.IVU,and CT.

Iodinated Contrast Iodinated Contrast AgentsAgents

NON-IONIC MONOMERSNON-IONIC MONOMERSModified tri-iodinated benzoic acid Modified tri-iodinated benzoic acid derivative with carboxyl group replaced derivative with carboxyl group replaced by D-glucose groupby D-glucose groupdo not dissociate and water-solubility do not dissociate and water-solubility due several hydrophilic hydroxyl groupsdue several hydrophilic hydroxyl groupsIodine: particle ratio 3: 1Iodine: particle ratio 3: 1Low osmolality 500-700 mosm/kgLow osmolality 500-700 mosm/kg

Non Ionic MonomerNon Ionic Monomer

NON-IONIC MONOMERNON-IONIC MONOMER

Iohexol (Omnipaque)Iohexol (Omnipaque) Iopamidol ( Lekpamidol)Iopamidol ( Lekpamidol) Iopentol (Imagopaque)Iopentol (Imagopaque) Iopromide (Ultravist)Iopromide (Ultravist) Ioversol (Optiray)Ioversol (Optiray)

Iodinated Contrast Iodinated Contrast AgentsAgents

Non ionic dimerNon ionic dimer Two non-ionic tri-iodinated benzene Two non-ionic tri-iodinated benzene

rings replacing both carboxyl groups rings replacing both carboxyl groups with hydrophilic groups.with hydrophilic groups.

Iodine:particle ratio 6:1Iodine:particle ratio 6:1 Low osmolality 300 mosm/kgLow osmolality 300 mosm/kg Examples: lotrolan, lodixanolExamples: lotrolan, lodixanol

Non Ionic DimerNon Ionic Dimer

Iodinated Contrast Iodinated Contrast AgentsAgents

Iodine : particle ratio = no. of iodine atoms per molecule Iodine : particle ratio = no. of iodine atoms per molecule of CM / no. of osmotically active particles per molecule of CM / no. of osmotically active particles per molecule of CMof CM

contrast contrast mediamedia

iodine iodine particle ratioparticle ratio

Ionic Ionic monomermonomer

3:23:2

Ionic dimerIonic dimer 6:26:2

Non ionic Non ionic monomermonomer

3:13:1

Non ionic Non ionic dimerdimer

6:16:1

Iodinated Contrast Iodinated Contrast AgentsAgents

Adverse reactions – TypesAdverse reactions – Types AcuteAcute

IdiosyncraticIdiosyncratic

Non – idiosyncraticNon – idiosyncratic DelayedDelayed

IDIOSYNCRATIC RXNSIDIOSYNCRATIC RXNS

MILDMILD

NauseaNausea

Ltd Ltd urticariaurticaria

Mild pallorMild pallor

Limb painLimb pain

MODERATEMODERATE

Sev.vomitiSev.vomitingng

Extensive Extensive UrticariaUrticaria

DyspnoeaDyspnoea

Chest/Chest/abdominal abdominal painpain

SEVERESEVERE

UnconsciouUnconsciousnesssness

Pulm.edemPulm.edemaa

Cardiac Cardiac arrestarrest

ArrythmiasArrythmias

Iodinated Contrast Iodinated Contrast AgentsAgents

Non-Idiosyncratic reactionsNon-Idiosyncratic reactions Physiologic effects: hypotension Physiologic effects: hypotension

associated with tachycardia due to associated with tachycardia due to peripheral vasodilatation.peripheral vasodilatation.

Vasovagal reactions: hypotension Vasovagal reactions: hypotension associated with bradycardia.associated with bradycardia.

Contrast induced renal failureContrast induced renal failure

ConvulsionsConvulsions

Cutaneous- Phlebitis/extravasationCutaneous- Phlebitis/extravasation

Iodinated Contrast Iodinated Contrast AgentsAgents

Delayed reactionsDelayed reactions Occur after 1 hour to 1 week Occur after 1 hour to 1 week - flu like symptoms - flu like symptoms - delayed arm pain- delayed arm pain - rash/ pruritus - rash/ pruritus - salivary gland swelling- salivary gland swelling - Steven Johnson syndrome- Steven Johnson syndrome more common with LOCMmore common with LOCM

Contra indicationContra indication

Risk factorsRisk factors Raised creatinine levelRaised creatinine level Dehydration Dehydration Congestive heart failure Congestive heart failure Age over 70 years oldAge over 70 years old

THANK YOUTHANK YOU