Contrast AgentsContrast Agents

Contrast AgentsContrast Agents

Compounds used to improve the Compounds used to improve the visibility of internal bodily structures visibility of internal bodily structures in an image.in an image.

Types:Types: Radiographic agents based on Radiographic agents based on

iodineiodine ionic or non-ionic agentsionic or non-ionic agents

Monomer or DimerMonomer or Dimer high osmolar, low osmolar, iso high osmolar, low osmolar, iso osmolarosmolar

Commonly used iodinated contrast Commonly used iodinated contrast

agentsagents NameName TypeType IodinIodin

e e ConteConte

ntnt

OsmolalOsmolalityity

IoniIonicc

DiatrizoateDiatrizoate (Hypaque 50)(Hypaque 50)

Ionic Ionic MonomerMonomer

300300 15501550

High High OsmolOsmol

ararMetrizoateMetrizoate (Isopaque (Isopaque Coronar 370) Coronar 370)

IonicIonic 370370 21002100

Ioxaglate Ioxaglate (Hexabrix)(Hexabrix)

IonicIonic 320320 580580

Low Low OsmolOsmol

ararNoNon-n-IoniIonicc

Iopamidol Iopamidol (Isovue 370)(Isovue 370)

Non-ionic Non-ionic monomermonomer

370370 796796

Iohexol Iohexol (Omnipaque (Omnipaque 350)350)

Non-ionicNon-ionic 350350 884884

Iodixanol Iodixanol (Visipaque (Visipaque 320)320)

Non-ionic Non-ionic dimerdimer

320320 290290 Iso Iso OsmolOsmol

arar

Ionic Contrast AgentsIonic Contrast Agents > 10 million diagnostic procedures / > 10 million diagnostic procedures /

year year Conventional ionic contrast Conventional ionic contrast

reactions - 10% reactions - 10% 1 in 1000 severe1 in 1000 severe

Contrast MythsContrast Myths not caused by iodine not caused by iodine not related to shellfish not related to shellfish not true allergy (no drug-antibody) not true allergy (no drug-antibody) mechanism remains unknown mechanism remains unknown

Anaphylactoid Anaphylactoid (idiosyncratic)(idiosyncratic)

unpredictable unpredictable dose independent dose independent prevalence 1-2% (0.04 - 0.22% prevalence 1-2% (0.04 - 0.22%

severe) severe) fatal 1 in 75,000 fatal 1 in 75,000

ChemotoxicChemotoxic

predictable predictable dose dependent dose dependent due to osmolality or ionic due to osmolality or ionic

compositioncomposition

Nonionic vs IonicNonionic vs Ionic Contrast reactions decreased 5 Contrast reactions decreased 5

fold fold Fatalities unchanged Fatalities unchanged

Risk Factors Risk Factors Previous contrast reaction either Previous contrast reaction either

moderate or severemoderate or severe asthma asthma allergy history requiring medical allergy history requiring medical

treatment treatment pretesting poor predictor of reaction pretesting poor predictor of reaction

Repeat Reactions, ionicRepeat Reactions, ionic bronchospasm 40% to facial edema bronchospasm 40% to facial edema

70% 70% decrease to 6 - 9% with pretreatment decrease to 6 - 9% with pretreatment decrease to 0.6% with pretreatment decrease to 0.6% with pretreatment

and switch to nonionicand switch to nonionic

Late Reactions Late Reactions

1 hr to 1 week following contrast 1 hr to 1 week following contrast injection injection

Headache, myalgias, fever, skin Headache, myalgias, fever, skin reactions reactions

Risk Factors Risk Factors Previous contrast reaction Previous contrast reaction Interleukin-2 treatment Interleukin-2 treatment

usually self-limited, treat severe usually self-limited, treat severe reactions with steroids reactions with steroids

Severity of Reactions - Severity of Reactions - Minor Minor

Nausea & vomiting Nausea & vomiting Urticaria Urticaria Pruritis Pruritis Diaphoresis Diaphoresis

Severity of Reactions - Severity of Reactions - Moderate Moderate

Faintness Faintness Facial edema Facial edema Laryngeal edema Laryngeal edema BronchospasmBronchospasm

Severity of Reactions - Severity of Reactions - Severe Severe

Pulmonary edema Pulmonary edema Respiratory arrest Respiratory arrest Cardiac arrest Cardiac arrest SeizuresSeizures

Renal Toxicity Renal Toxicity (increased serum creatinine by more than 25% (increased serum creatinine by more than 25%

or > 0.5 mg%)or > 0.5 mg%) 2-7% 2-7% Risk Factors Risk Factors

5 - 10 fold increase with pre-existing 5 - 10 fold increase with pre-existing renal insufficiency (increased renal insufficiency (increased creatinine) creatinine)

Dehydration Dehydration CHF CHF Age > 70 Age > 70 Taking nephrotoxic drugs Taking nephrotoxic drugs

(nonsteroidal inflammatory agents, (nonsteroidal inflammatory agents, gentomycin etc.) gentomycin etc.)

Renal Toxicity Renal Toxicity (increased serum creatinine by more than 25% (increased serum creatinine by more than 25%

or > 0.5 mg%)or > 0.5 mg%) direct relationship between serum direct relationship between serum

creatinine and likelihood creatinine and likelihood nephrotoxicity nephrotoxicity

Hydrate 100 ml/hr Normal saline 4 Hydrate 100 ml/hr Normal saline 4 hrs prior to procedure, continue for hrs prior to procedure, continue for 24 hours 24 hours

Those on hemodialysis do not need Those on hemodialysis do not need extra sessions or dialysis extra sessions or dialysis immediately following contrast immediately following contrast administrationadministration

Metformin (Glucophage) Metformin (Glucophage)

oral diabetic agent oral diabetic agent patients with renal insufficiency patients with renal insufficiency

may develop lactic acidosis may develop lactic acidosis withhold drug for 48 hrs after withhold drug for 48 hrs after

contrast administration in all contrast administration in all patients taking this drugpatients taking this drug

Screening Creatinine Screening Creatinine

Which patients need screening Which patients need screening creatinine?creatinine?Consider if patient has one of the Consider if patient has one of the following risk factors:following risk factors: Known renal insufficiency Known renal insufficiency Diabetes mellitus Diabetes mellitus Lasix or nephrotoxic drugs Lasix or nephrotoxic drugs Solitary kidney Solitary kidney

Treatment Contrast Treatment Contrast Reactions Reactions

Nausea & VomitingNausea & Vomiting usually self-limited usually self-limited protracted: Prochlorperazine protracted: Prochlorperazine

(Compazine) 5-10 mg IM (Compazine) 5-10 mg IM UrticariaUrticaria

Diphenhydramine (Benadryl) 25 - Diphenhydramine (Benadryl) 25 - 50 mg IM, caution: drowsiness 50 mg IM, caution: drowsiness

add Cimetidine (Tagamet) 300 mg add Cimetidine (Tagamet) 300 mg in 20 ml, IV slowlyin 20 ml, IV slowly

Treatment Contrast Treatment Contrast Reactions Reactions

HypotensionHypotension Bradycardia (Vasovagal)Bradycardia (Vasovagal)

elevate legs (infuses 700 ml) elevate legs (infuses 700 ml) IV fluid (normal saline) IV fluid (normal saline) O2 3 L/min O2 3 L/min atropine 0.6 mg IV push, repeat up to 3 atropine 0.6 mg IV push, repeat up to 3

mg totalmg total TachycardiaTachycardia

elevate legs elevate legs IV fluid (normal saline) may require > 1 IV fluid (normal saline) may require > 1

Liter Liter O2 3 L/min O2 3 L/min

Treatment Contrast Treatment Contrast ReactionsReactions

Bronchospasm or laryngeal edemaBronchospasm or laryngeal edema O2 3 L/min O2 3 L/min Epinephrine 1:1000 (0.1 - 0.2 ml Epinephrine 1:1000 (0.1 - 0.2 ml

subq) or 1:10,000 1 ml IV over 3 min subq) or 1:10,000 1 ml IV over 3 min Beta 2 agonist 2 -3 puffs Beta 2 agonist 2 -3 puffs

albuterol (Proventyl) albuterol (Proventyl) metaproterenol (Alupent) metaproterenol (Alupent) terbutaline (Brethaine) terbutaline (Brethaine)

Treatment Contrast Treatment Contrast ReactionsReactions AnaphylactoidAnaphylactoid

O2 3 L/min O2 3 L/min IV normal saline IV normal saline Epinephrine Epinephrine Benadryl 25 - 50 mg IV Benadryl 25 - 50 mg IV Tagamet 300 mg in 20 ml IV slowly Tagamet 300 mg in 20 ml IV slowly Solu-medrol 1 gm IV Solu-medrol 1 gm IV

Note: if patient taking beta blocker Note: if patient taking beta blocker glucagon 1 - 5 mg IV bolus followed by glucagon 1 - 5 mg IV bolus followed by

infusion 5-15 ug/min or infusion 5-15 ug/min or isoproternol 1:5000 (0.2 mg/ml) isoproternol 1:5000 (0.2 mg/ml)

IV 0.5 - 1.0 ml diluted in 10 ml IV 0.5 - 1.0 ml diluted in 10 ml 1 mg increments 1 mg increments

Treatment Contrast Treatment Contrast ReactionsReactions SeizuresSeizures

protect airway protect airway Diazepam (valium) 5 mg IV slowlyDiazepam (valium) 5 mg IV slowly

Suspected pheochromocytomaSuspected pheochromocytoma phentolamine (Regitine) 5.0 ml (5 phentolamine (Regitine) 5.0 ml (5

mg) IV bolusmg) IV bolus PregnancyPregnancy

Discard breast milk for 24 hours Discard breast milk for 24 hours following contrast administrationfollowing contrast administration

ExtravasationExtravasation Elevate extremity Elevate extremity Ice pack 3x day Ice pack 3x day Observe for 2-4 hours if volume Observe for 2-4 hours if volume

> 5ml> 5ml

ExtravasationExtravasation Plastic Surgery ConsultationPlastic Surgery Consultation

ionic > 30 ml ionic > 30 ml nonionic > 100 ml nonionic > 100 ml skin blistering/significant tissue skin blistering/significant tissue

damagedamage altered tissue perfusion altered tissue perfusion increasing pain after 2-4 hours increasing pain after 2-4 hours change in sensation distal to site change in sensation distal to site

of extravasationof extravasation

Pretreatment ProtocolsPretreatment Protocols

Reduces minor reactionsReduces minor reactions Benadryl 50 mg IM or PO 1 hr Benadryl 50 mg IM or PO 1 hr

before procedure before procedure Prednisone 50 mg PO 13, 7, 1 hr Prednisone 50 mg PO 13, 7, 1 hr

before procedure before procedure Observe patient at least 30 Observe patient at least 30

minutes following injection minutes following injection

Pretreatment ProtocolsPretreatment Protocols

Reduction of NephrotoxicityReduction of Nephrotoxicity Creatinine level > 2 mg/dlCreatinine level > 2 mg/dl Hydrate patient - Oral fluids if Hydrate patient - Oral fluids if

unable to drink use IV salineunable to drink use IV saline Mild Renal Insufficiency Patients – Mild Renal Insufficiency Patients –

add N-acetyl-cysteine (Mucomyst) : add N-acetyl-cysteine (Mucomyst) : 600 or 1,200 mg PO BID the day 600 or 1,200 mg PO BID the day before and day of the procedure or before and day of the procedure or 150 mg/kg IV over .5 hr or 50 mg/kg 150 mg/kg IV over .5 hr or 50 mg/kg IV over 4 hrIV over 4 hr

Risk of NephropathyRisk of Nephropathy

A recent meta analysis: A recent meta analysis: Radiology: Volume 239: May Radiology: Volume 239: May 2006 p.392-397: Drs Rao & 2006 p.392-397: Drs Rao & NewhouseNewhouse

Properly controlled clinical Properly controlled clinical studies of IV administered studies of IV administered radiographic contrast media fail radiographic contrast media fail to demonstrate renal damage.to demonstrate renal damage.

ACR Manual on Contrast ACR Manual on Contrast Media Media

guide for radiologists in the use guide for radiologists in the use of iodinated contrast mediaof iodinated contrast media

hhttp://ttp://www.acr.org/s_acr/sec.asp?CIDwww.acr.org/s_acr/sec.asp?CID=2131&DID=16687=2131&DID=16687

References of InterestReferences of Interest

Guidelines for Contrast Media Guidelines for Contrast Media from the European Society of from the European Society of Urogenial Radiology: AJR:181, Urogenial Radiology: AJR:181, December 2003 p. 1463 – 1471.December 2003 p. 1463 – 1471.

Minimizing Adverse Reactions to Minimizing Adverse Reactions to Contrast Agents: Radiology Contrast Agents: Radiology Rounds, Massachusetts General Rounds, Massachusetts General Hospital, Volume 1, Issue 5 Oct Hospital, Volume 1, Issue 5 Oct 2003.2003.