Contrast

CT and MRI contrast information page:

IV Contrast: We typically follow MGH guidelines for the administration of IV contrast. Excellent discussion of Contrast Induced Nephropathy (CIN) and Nephrogenic Systemic Fibrosis (NSF) at that link.

MRI contrast: GFR >30 OK. For GFR 15-30 consult radiologist. Can be approved if needed after consulting with patient. All MRI’s have non-contrasted sequences. After contrast is administered T1 fat saturated images are performed. All fluid sensitive sequences (FLAIR in brain, STIR/T2 fat saturated sequences body/bone, Diffusion) are non-contrast as Gadolinium only affects T1 images.

CT contrast: GFR > 60 recommended. For outpatients with GFR between 30 and 60 the benefits of the procedures vs risks should be weighed. If approved discuss risk/benefits with patients. Then  hydration with increased oral intake day prior to/and after exam and administration of IV saline bolus 250 CC prior to and after procedure or aggressive oral hydration starting the day prior to procedure and continuing for 24 hours after procedure. Follow-up Cr/GFR 24-48 hours after exam.  Discontinue nephrotoxic medications (such as glucophage). Restart after GFR shows no findings of Contrast induced nephrophathy. Mucomyst 600mg PO BID on day of exam can be considered although efficacy is questioned. IV contrast should not be given if there is progressive decline in renal function. Exceptions can be made in emergent cases after discussion of risks with the patient.

CT contrast minor allergy: Consider MRI or non-contrast exam. If contrast needed premedication with prednisone 50 mg PO 13, 7, and 1 hour prior to exam with benedryl 50 mg PO 1 hour prior is recommended. For emergent cases protocols vary and are considered suboptimal. Recommended protocol from MUSC of Methylprednisolone (Solumedrol) 125 mg IV, Diphenhydramine (Benadryl®) 50 mg IV time one dose and Famotidine (Pepcid®) 20 mg IV time one dose. For significant allergy history such as respiratory distress please consult with radiologist. There is no known cross-reactivity of CT contrast allergy and shellfish allergy.

MR contrast (Gadolinium) does not cross react with CT contrast and allergy is extremely rare.

Figure 2.  Guidelines for risk stratification and prophylaxis for CIN
High Risk Intermediate Risk Low Risk

Estimated GFR < 30 mL/min/1.73 m2

Estimated GFR 30-60
mL/min/1.73 m2
Estimated GFR > 60
mL/min/1.73 m2
Contrast Administration Avoid contrast* Administer contrast Administer contrast
Oral Hydration N/A Encouraged, starting on day prior to examination Encouraged, starting on day prior to examination
IV Hydration N/A Inpatients:

Normal (0.9%) saline infused at 1 mL/kg for 24 hours starting 12 hours prior to contrast exposure (Half-normal saline (0.45%) if patient has evidence of CHF)

Outpatients:

IV Bolus hydration (250 cc before and after study)

N/A
N-Acetylcysteine (Mucomyst)† (Optional) N/A 600mg PO BID starting on day prior and for 48 hours after study N/A
Nephrotoxic Medications N/A Discontinue nephrotoxic
medications at least 48 hours prior; resume 48 hours after if
no evidence of CIN
N/A
Follow-up N/A Obtain follow-up serum creatinine in 24 – 48 hours N/A
* If contrast administration is required in high-risk patients, direct discussion with a radiologist and clinical nephrology service is recommended for a patient-specific imaging and prophylaxis strategy.

†N-acetyl cysteine is an optional prophylactic measure for CIN as no convincing evidence of efficacy is available.

 

Table 1. Predisposing factors for the development of contrast-induced nephropathy with CT examination
Coexisting medical/demographic factors:
– Renal insufficiency
– Diabetes
– Congestive heart failure
– Dehydration
– Age > 75 yrs
– Multiple myeloma
Concurrent use of potentially nephrotoxic medications:
– Non-steroidal anti-inflammatory agents (NSAIDS)
– Cisplatin-based chemotherapy agents
– Aminoglycoside antibiotics
– Iodinated contrast within last 72 hours
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