contrast agents in radiology
DESCRIPTION
TRANSCRIPT
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.