Radiographic and magnetic resonances contrast agents: Essentials and tips for safe practices

Table 1 Risk factors that predispose patients to contrast medium reactions

Patients with a prior history of allergy to CM (3-6 folds)

Patients with a prior history of allergic reactions to drugs and foods

Patients with generalized atopic tendencies (e.g., asthma and hay fever)

Dehydration states

Age extremes (less than 5 yr and older than 60 yr)

Serious illness and chronic debilitating conditions, e.g., CVS diseases and renal failure

Anemia

Certain co-medications, e.g., β-blockers and metformin

Malignancies

Patient’s anxiety due to public concerns about CM-induced reaction

CM: Contrast media; CVS: Cardiovascular.

Table 2 Co-morbidities indicating renal profile checkup prior to contrast agent administration

Age extremes	Older than 60 yr and less than 5 yr
History of relevant renal disorders	Anatomic variations: Solitary kidney and horse-shoe kidney
	Renal surgeries
	Renal endangering medications, e.g., NSAIDs and chemotherapy
	Renal-induced nephropathy (prior)
	History of prior renal dialysis
	Renal malignancies
Nephropathy-associated chronic diseases	E.g., uncontrolled DM, hypertension and hyperuricemia
Drugs interfering with renal excretions	Metformin

NSAIDs: Nonsteroidal antiinflammatory drugs; DM: Diabetes mellitus.

Table 3 Common elective premedication protocols for high-risk patients to develop iodinated contrast medium hypersensitivity reactions

Elective		Emergency
Lasser protocol	Greenberger protocol1	IV protocols (in descending order of desirability)
Oral prednisone 50 mg at 13/7 and 1 h before contrast medium injection	Oral methylprednisolone 32 mg at 12 and 2 h before contrast medium injection +/-	Methylprednisolone sodium succinate 40 mg
		OR
		hydrocortisone sodium succinate 200 mg
		every 4 h till examination
		+ diphenhydramine 50 mg IV - 1 h
+ (oral/IM or IV) diphenhydramine 50 mg just 1 h before examination	+/- (oral/IM or IV) diphenhydramine 50 mg just 1 h before examination	No corticosteroids at all
		(not preferable)
		Only diphenhydramine 50 mg IV

¹IV hydrocortisone 200 mg may be a substitute for oral prednisone, if the patient cannot tolerate oral medication.

Table 4 Severity scale, signs, symptoms and management options of adverse reactions to contrast media

Category of reaction	Symptoms	Treatment
Mild (self-limited without evidence of progression)	Hives, rashes and sweats	Patient reassurance usually suffices in some cases
	Nasal symptoms	Close observation till resolution of symptoms
	Nausea, vomiting	May require symptomatic treatment in some cases
	Pallor
	Cough
	Flushing
	Warmth
	Chills
	Headache and/or Dizziness
	Self limited anxiety
Moderate (signs and symptoms are more pronounced)	Generalized or diffuse erythema	Requires prompt treatment
	Tachycardia/bradycardia	Requires close, careful observation for possible progression to a life-threatening event
	Bronchospasm, wheezing and/or dyspnea
	Hypo- or hyper-tension
	Voice hoarseness
Severe (sign and symptoms are often life-threatening)	Laryngeal edema (severe or rapidly progressing)	Requires hospitalization and aggressive treatment by emergency teams
	Convulsions
	Profound hypotension
	Unresponsiveness
	Clinically manifest arrhythmias
	Cardiopulmonary arrest

Table 5 The criteria for diagnosing contrast induced-acute kidney injury

Absolute serum creatinine increase of greater than or equal to 3.0 mg/dL (> 26.4 μmol/L)

An increase in the percentage of serum creatinine of greater than or equal to 50%

Urine output reduced to less than or equal to 0.5 mL/kg per hour for at least 6 h

Table 6 European medicines agency nephrogenic systemic fibrosis-risk stratification categorization of gadolinium-based contrast agent

GBCA NSF-risk class	Scientific (generic) name
Highest risk of NSF	Gadodiamide (Omniscan®)
	Gadopentetatedimeglumine (Magnevist®)
	Gadoversetamide (Optimark®)
Intermediate risk of NSF	Gadobenatedimeglumine (Multihance®)
	Gadofosvesettrisodium (Vasovist®, Ablavar®)
	Gadoxetate disodium (Primovist®, Eovist®)
Lowest risk of NSF	Gadobutrol (Gadovist®)
	Gadoteratemeglumine (Dotarem®)
	Gadoteridol (Prohance®)

NSF: Nephrogenic systemic fibrosis; GBCA: Gadolinium-based contrast agent.

Table 7 Strategies for safe clinical practice of contrast media to reduce risk for renal complications in patients with renal problems

Patients with SCr ≥ 2 g/dL and/or eGFR ≤ 60 mL/min per 1.73 m2	Withhold contrast whenever possible and use alternative imaging modalities if feasible
	Adequate hydration
Patients with end-stage renal disease who still produce urine	Consider alternative diagnostic study if feasible
	Avoid use of CM whenever possible
	Use lowest possible dose of contrast
	Use intermediate to low osmolar and/or low risk GBCA
	followed by prompt dialysis if the patient is already undergoing dialysis
Patients with end-stage renal disease who are anuric	Can receive routine volumes of intravenous contrast material without risk for further renal damage or the need for urgent dialysis

GBCA: Gadolinium-based contrast agent; CM: Contrast media; eGFR: Estimated glomerular filtration rate.

Table 8 Practical guidelines for safe contrast media-metformin interaction

Renal function (eGFR-indexed)	Action
Patients with normal renal function (eGFR ≥ 60 mL/min per 1.73 m2)	No need to withhold metformin
Patients with compromised renal function (eGFR ≥ 30 but ≤ 60 mL/min per 1.73 m2)	Withhold metformin for 48 h
	Re-institution after renal function monitoring
Patients with compromised renal function (eGFR < 30 mL/min per 1.73 m2)	Have not to be on metformin
	Consult nephrologist

eGFR: Estimated glomerular filtration rate.