SPHP Radiology Protocols

link to 2020 ACR contrast 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.

GFR >/= 30 mL/min: Low risk.   At the current time, there is very little evidence that intravenous iodinated contrast material is an independent risk factor for AKI

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 2020 document:
There is no agreed-upon threshold of serum creatinine elevation or eGFR declination beyond which the risk of CIN 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].

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 CIN 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. As previously stated, no serum creatinine or eGFR threshold is adequate to stratify risk for patients with AKI because serum creatinine in this setting is unreliable. However, in patients with AKI, the administration of iodinated contrast medium should only be undertaken with appropriate caution, and only if the benefit to the patient outweighs the risk. There have been no published series demonstrating that IV iodinated contrast medium administration to patients with AKI leads to worse or prolonged renal dysfunction than would occur in a control group. However, patients with AKI are particularly susceptible to nephrotoxin exposure and therefore it is probably prudent to avoid intravascular iodinated contrast medium in these patients when possible.

OUTPATIENTS:

THE FOLLOWING OUTPATIENTS PATIENTS SHOULD HAVE A RECENT GFR (within 90 days) prior to CT

Age > 60 years
History of kidney disease/renal insufficiency
History of prior dialysis
Single kidney
Prior renal surgery
Prior renal cancer
Diabetes
Patients on Metformin* (theoretical risk for lactic acidosis)
Hypertension requiring medical therapy

ED/INPATIENTS:

All inpatients and ED patients should have a current GFR (within 72 hours).

IV HYDRATION INSTRUCTIONS after IV contrast administration for inpatients/ED patients at risk of contrast nephropathy:

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.

REDUCED CONTRAST DOSE GUIDELINES

If full dose is 125 mL, give 90 mL.
If full dose is 100 mL, give 75 mL.
If full dose is 80 mL, give 60 mL.

link to IV contrast guidelines form

link to IV contrast screening form (for patient/patient's representative)

link to patient IV contrast alert/follow-up form

link to clinician IV contrast alert/follow-up form

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

Excerpt from ACR statement on contrast media (2020):

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 - One 16 oz cup in room prior to scanning

Pancreas protocol
Liver protocol
Urogram
Renal mass
Adrenal protocol

WATER - Two 16 oz cups prior to exam (within 2 hours)

Abdominal pain
Diverticulitis
Obstruction
Mass
Hernia
Metastatic work-up/follow-up

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 water soluble positive oral contrast --> 50 mL Isovue mixed with 1000 mL Crystal Light

Outpatient water soluble positive oral contrast --> Gastrografin

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

2. If any of these symptoms are present notify Radiology Dept. immediately at 525-1818.

3. Elevate the affected extremity.

4. Apply ice (20 min. on, 20 min. off, repeat).

5. Take Acetaminophen/Tyelenol one to two 325 mg tablets q 4 to 6 hours as needed for discomfort.

6. Questions or problems: 535-1818 or 525-1807 after hours.

7. The radiology nurse will follow up with the patient by phone until the site is healed.

link to IV contrast extravasation instructions

link to patient safety event form

PREMEDICATION FOR IV CONTRAST ALLERGY

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.

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

link to PE Pregnancy document

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.