CT IV and ORAL CONTRAST
(Updated 10/10/2025, reviewed 10/10/2025)
LIFE/LIMB POLICY — If the ordering provider believes that a potential life or limb-threatening process outweighs the risks of IV contrast administration (e.g., suspected aortic dissection, large vessel occlusion, acute stroke), IV contrast may be administered by the technologist if appropriately documented in the electronic medical record by the provider.
Please refer to official hospital policy document
IODINATED IV CONTRAST GUIDELINES IN RENAL INSUFFICIENCY
Patients with renal insufficiency are at increased risk of post-contrast acute kidney injury following administration of CT IV contrast.
Patient Screening Questions (when CT IV contrast is requested):
-Do you have a history of chronic kidney disease, kidney surgery, kidney ablation, albuminuria?
If the answer is yes to any of those questions, radiology nurse will review patient charts and approve IV contrast. These patients should have kidney function labs within 90 days.
Sometimes patients inadvertently answer no, but technologist catches a possible discrepancy. The techs will flag these cases for nurse review also.
GFR < 30 mL/min: Higher risk. This cohort of patients appears to be at greatest risk for post-contrast acute kidney injury after administration of intravenous iodinated contrast. Administration of IV contrast is a matter of clinical judgement. If the benefits of IV contrast outweigh the risks, contrast may be administered at the discretion of the ordering healthcare provider. Examples include (but are not limited to) clinical scenarios of possible pulmonary embolism, aortic dissection, acute limb ischemia.
| GFR | ACTION |
|---|---|
| >/= 30 mL/min | may receive IV contrast |
| <30 mL/min | An alternative exam should be considered. In cases of necessity (eg, dissection, PE, acute limb ischemia) if there is no acceptable alternative exam, may receive IV contrast with hydration. Consider reduced contrast dose (3/4). Avoid volume depletion. Limit repeat contrast administration Consider temporary discontinuation of nephrotoxic medications, at the discretion of referring provider Clinical follow up of renal function is recommended |
| Acute renal insufficiency | GFR may be unreliable. IV contrast should be avoided if possible. An alternative exam should be considered. In cases of necessity (eg, dissection, PE, acute limb ischemia) if there is no acceptable alternative exam, may receive IV contrast with hydration. considered. Consider reduced contrast dose (3/4) Avoid volume depletion Limit repeat contrast administration Consider temporary discontinuation of nephrotoxic medications, at the discretion of referring provider Clinical follow up of renal function is recommended |
Excerpt from ACR Contrast Media 2025 document:
There is no agreed-upon threshold of serum creatinine elevation or eGFR declination beyond which the risk of CI-AKI is considered so great that intravascular iodinated contrast medium should never be administered. In fact, since each contrast medium administration always implies a risk-benefit analysis for the patient, contrast medium administration for all patients should always be taken in the clinical context, considering all risks, benefits and alternatives [2,6].
Some practices have advocated stratification of potential risk by eGFR instead of serum creatinine because it is a better indicator of baseline renal function [49,50]. This has been limited in the past by insufficient data [68-70], but there are now two large propensity score-adjusted studies that stratify CI-AKI risk by eGFR [3,7]. One showed no risk of CI-AKI from IV iodinated contrast material, regardless of baseline eGFR [7], while another identified patients with an eGFR <30 mL / min/1.73m2 to be at significant risk (patients with eGFR 30-44 mL / min/1.73m2 were at borderline but not statistically significant risk) [3].
At the current time, there is very little evidence that IV iodinated contrast material is an independent risk factor for AKI in patients with eGFR ≥30 mL / min/1.73m2. Therefore, if a threshold for CI-AKI risk is used at all, 30 mL / min/1.73m2 seems to be the one with the greatest level of evidence [3]. Any threshold put into practice must be weighed on an individual patient level with the benefits of administering contrast material.
Contrast-enhanced CT has superior diagnostic performance compared to unenhanced CT for a wide array of indications. Failure to diagnose an important clinical entity carries its own risk.
ED/INPATIENTS:
All inpatients and ED patients should have a current GFR (within 72 hours).
- 0.9% normal saline at 100 mL/hr IV beginning 6-12 hrs prior to contrast and continuing 4-12 hrs after
Outpatients should be instructed to hydrate orally, and follow up with their physician.
METFORMIN
At SPH, CT contrast policy per the pharmacy department Metformin protocol. Patients receiving IV contrast should discontine metformin per Pharmacy Orders.
Other facilities follow ACR guidelines:
In patients with GFR >/=30 mL/min, there is no need to discontinue metformin.
Metformin containing medications: Glucophage, Fortamet, Glumetza, Riomet, Glucovance, Metaglip, ActosPlus, Prandimet, Avandamet, Kombiglyze, Janumet.
Regarding IV contrast & Metformin
Prior guidelines from the American College of Radiology recommended withholding metformin when a patient was planned to receive intravascular iodinated contrast based on the theoretical risk of patients developing contrast-induced nephropathy and therefore retaining metformin within the body. However further examinations of the rare cases of metformin-associated lactic acidosis have revealed that almost all cases occurred when patients were receiving metformin despite having one or more patient-associated contraindications to receiving this drug. There have been no reports of lactic acidosis in patients properly selected for metformin therapy. As a result, recent guidelines from the American College of Radiology are more measured in the management of this medication around the time of intravascular iodinated contrast administration:
Category I
In patients with no evidence of AKI and with eGFR ≥30 mL / min/1.73m2 , there is no need to discontinue metformin either prior to or following the intravenous administration of iodinated contrast media, nor is there an obligatory need to reassess the patient’s renal function following the test or procedure.
Category II
In patients taking metformin who are known to have acute kidney injury or severe chronic kidney disease (stage IV or stage V; i.e., eGFR< 30), or are undergoing arterial catheter studies that might result in emboli (atheromatous or other) to the renal arteries, metformin should be temporarily discontinued at the time of or prior to the procedure, and withheld for 48 hours subsequent to the procedure and reinstituted only after renal function has been re-evaluated and found to be normal
INDICATIONS FOR CT IV CONTRAST
| ABDOMEN/PELVIS INDICATION | IV CONTRAST | NOTES |
|---|---|---|
| Abdominal Pain | yes | |
| Metastasis | yes | |
| H/O Cancer | yes | |
| Fever | yes | |
| Abscess | yes | |
| Diverticulitis | yes | |
| Appendicitis | yes | |
| Colitis | yes | |
| Peritonitis | yes | |
| Crohn's Disease | yes | |
| Solid Organ Mass, Mass | yes | |
| Trauma | yes | |
| Abnormal LFTs | yes | |
| Hiatal Hernia | yes | |
| Abdominal Wall Hernia | yes | |
| Hernia with Pain | yes | |
| Bowel Obstruction | yes | |
| Mesenteric Ischemia | yes | |
| Ischemic Bowel | yes | |
| Kidney Stones | no | Stone Protocol, Prone |
| Hematuria | yes | Urogram or Renal Mass pre/post |
| Cholelithiasis | yes | |
| Biliary Obstruction or Stone | yes | |
| Adrenal Mass | yes | Adrenal Protocol |
| AAA (preop or symptoms) | yes | CTA |
| AAA (f/u size, asymptomatic) | no | |
| AAA post-stent | yes | Endograft |
| Renal Artery Stenosis | yes | CTA |
| Leaking AAA | yes | CTA |
| Bowel Perforation | yes | |
| Adenopathy | yes |
| CHEST INDICATION | IV CONTRAST | NOTES |
|---|---|---|
| Hilar Mass | yes | |
| Mediastinal Mass | yes | |
| Lung Mass/Nodule | yes | Initial Eval |
| Lung Nodule f/u size | no | follow up |
| Lymphoma | yes | |
| Adenopathy | yes | |
| Pneumonia | yes | |
| Pleural Effusion, Empyema | yes | |
| Pulmonary Embolism | yes | CT PE |
| Interstitial Lung Disease | no | HRCT |
| Aneurysm | yes | CTA |
| Dissection | yes | Dissection |
| Esophageal Leak, Boerhaave's | yes | drink on table |
ORAL CONTRAST PROTOCOLS
WATER –
- Generally, the default oral contrast prep
- Do not give water if vomiting, NPO, or fluid restricted
- Two 16 oz cups prior to exam (within 2 hours)
- Plus 8 to 16 oz on the table, when possible to help distend the stomach
POSITIVE ORAL CONTRAST
- Evaluation for bowel leak, fistula, abscess (water soluble)
- Recent bowel surgery within 3 months (water soluble)
- Research patients where protocol includes it
- Referring MD request
- Acute abdominal pain in pediatric patients
- Evaluation for appendicitis in pediatric patients and patients with BMI <25
Outpatient Barium Based positive oral contrast –> Readi-Cat smoothie (2) + water just prior to scan
Inpatient / ED / in-office outpatient water soluble positive oral contrast –> 50 mL Isovue mixed with 1000 mL Crystal Light
*water soluble oral contrast is only administered on-site
IV CONTRAST EXTRAVASATION
1. Evaluate the affected extremity for
- Redness, discoloration
- Increasing pain
- Blistering
- Firmness, induration
- Unusually hot or cold
- Changes in sensation (numbess, tingling)
- Decreased distal pulses
PREMEDICATION FOR IV CONTRAST ALLERGY
*Patients with history of contrast reaction receiving premedication should be scheduled at acute care locations*
Elective Premedication for mild or moderate reaction (patients with severe reaction should avoid IV contrast):
STANDARD REGIMEN:
Prednisone – 50 mg by mouth at 13 hours, 7 hours, and 1 hour before contrast media injection, plus Diphenhydramine (Benadryl) – 50 mg orally, intravenously, or intramuscularly 1 hour before contrast medium.
Alternative Regimens:
2. Methylprednisolone (Medrol) – 32 mg by mouth 12 hours and 2 hours before contrast media injection. An anti-histamine (as in option 1) can also be added to this regimen injection.
3. If the patient is unable to take oral medication, 200 mg of hydrocortisone intravenously may be substituted for oral prednisone
Emergency Premedication Options (option 1 preferred):
1. Methylprednisolone sodium succinate (Solu-Medrol) 40 mg or hydrocortisone sodium succinate (Solu-Cortef®) 200 mg intravenously 5 hours before and 1 hour before contrast injection. Plus diphenhydramine 50 mg IV 1 hour prior to contrast injection.
2. Dexamethasone sodium sulfate (Decadron) 7.5 mg 5 hours before and 1 hour before contrast study if patent with known allergy to methylprednisolone. Plus diphenhydramine 50 mg IV 1 hour prior to contrast injection.
***Note: IV steroids have not been shown to be effective when administered less than 4 to 6 hours prior to contrast injection.***
In cases where provider has invoked and documented life or limb exception (stroke, aortic dissection, arterial embolism) procedure includes: Solumedrol 125 mL IV x1, diphenhydramine 50 mg IV x1, famotidine 20 mg IV x1, wait 5 minutes after all three medications are administered to give IV contrast. Follow all precautions in official department protocol.
Patients that are at high risk for contrast reaction should be scheduled in inpatient CT/hospital, rather than outpatient setting.
IV CONTRAST AND BREASTFEEDING
The amount of contrast material passing into the breast milk and absorbed by the infant’s gut is small, and per the ACR guidelines, the patient may continue to nurse during the time period following IV contrast administration. If the mother remains concerned about any ill-effects, she may choose to pump and discard her breast milk 12 to 24 hours after contrast administration, but there is insufficient data to prove that this is necessary.
PE AND PREGNANCY
ALGORITHM FOR SUSPECTED PE IN PREGNANT PATIENTS
Proposed/Draft 01/23/2014
RECOMMENDATIONS
The algorithm proposed by the American Thoracic Society advocates for performing a V/Q scan in the setting of a normal CXR, and a CTPA in the setting of an abnormal CXR. This places a higher value on minimizing radiation dose to the mother and a lower value on rapidity of diagnostic testing and the possibility of alternative diagnoses afforded by CTPA. In our current practice, V/Q scan is limited by off-hours availability, slower acquisition time, potentially equivocal results, and the inability to provide an alternative diagnosis. In addition, dose models in the literature do not account for state-of-the-art low dose CT protocols utilizing tube current modulation of mA and kV, which significantly lower the dose of CTPA while preserving diagnostic accuracy. Current data for absolute quantification of dose reduction is limited, although studies propose 30-75% reductions in effective dose with these techniques.
While low dose CTPA still delivers a higher maternal dose than V/Q scan, the diagnostic accuracy, availability, and rapidity of acquiring the test, and the ability to offer an alternative diagnosis render CTPA the recommended examination at our institutions (see algorithm). If maternal radiation exposure or exposure to iodinated contrast material is a significant clinical concern to the referring healthcare provider in a specific situation, then V/Q scan can be considered as the examination of choice in the setting of a normal chest radiograph. In these instances, prophylactic anticoagulant therapy may be necessary while awaiting the exam given the limited off-hour availability of V/Q scans.