GIST Support Wiki

 
CT Intravenous Contrast

Intravenous contrast is used during computed tomography (CT scans) to show blood supply and blood flow. For GIST patients the contrast shows the vascularity of any tumors.

The most common contrast is iodine-based. A small percentage of patients may have allergic reactions to iodine contrast and need to take Benadryl and prednisone before the scan to prevent rash.

Here is a link to a free-access document by the American College of Radiology regarding contrast media: [1]

Patients with at-risk kidney function (indicated by elevated creatinine levels or depressed estimated glomerular filtration rate (EGFR) of less than 60) may experience kidney damage from iodine contrast. Some people with normal kidney function may also be susceptible to kidney damage. Several medical papers have suggested strategies to prevent such damage, including drinking lots of water and taking N-acetylcysteine at intervals prior to and after the scan. Note that although N-acetylcysteine is sold as an over-the-counter health supplement, when it is to be used to prevent contrast-induced nephropathy then a prescription product is called for. One member reports that the doctor calls in a prescription that the pharmacist mixes up to taste better, and that the mixture must be refrigerated.


Here are several references about preventing contrast-induced kidney damage.

Kelly AM, Dwamena B, Cronin P, Bernstein SJ, Carlos RC. Meta-analysis: effectiveness of drugs for preventing contrast-induced nephropathy. Ann Intern Med. 2008 Feb 19;148(4):284-94. PMID: 18283206 and direct link to free-access full paper

Pannu N, Wiebe N, Tonelli M; Alberta Kidney Disease Network. Prophylaxis strategies for contrast-induced nephropathy. JAMA. 2006 Jun 21;295(23):2765-79. Review. PMID: 16788132 free access through PubMed

Marenzi G, Assanelli E, Marana I, Lauri G, Campodonico J, Grazi M, De Metrio M, Galli S, Fabbiocchi F, Montorsi P, Veglia F, Bartorelli AL. N-acetylcysteine and contrast-induced nephropathy in primary angioplasty. N Engl J Med. 2006 Jun 29;354(26):2773-82. PMID: 16807414 free access through PubMed

Zagler A, Azadpour M, Mercado C, Hennekens CH. N-acetylcysteine and contrast-induced nephropathy: a meta-analysis of 13 randomized trials. Am Heart J. 2006 Jan;151(1):140-5. PMID: 16368307

Medscape article "Contrast Media Reactions Pose Serious Risk of Nephropathy". Access to Medscape is free after you complete a free registration.

One patient with pre-existing kidney damage reports the following strategy to allow her to receive CT scans with contrast without further worsening her kidney function:

I have worsening chronic renal failure (had it prior to GIST) HOWEVER it is NOT directly related to Gleevec; the contrast for CTs can have a bad effect on the kidneys if specific protective measures are not taken: Dr Stinchcombe referred me to a Renal Specialist at UNC- Dr Phillip Klemmer- tests were done and between the two of them STANDING ORDERS were made for each time I need a CT; I am admitted and given AT LEAST 12 hours of IV hydration as well as oral "push" of fluids and given Lazix q 12 hours- they set a GFR I must meet before the contrast is given; I & O is strictly measured and Creatinine studies are done at admission and before the CT then 30-45 min after the CT; th en after the CT I get AT LEAST 12 hours IV fluid and push oral hydration with Lasix q 12 hours with creatinine done prior to discharge (again reaching THEIR set levels) ... this may NOT be the routine your ncologist/nephrologist would recommned however I would suggest that you discuss this with a Reanl specialist. MY GFR is currently at 40% which is technically below the allowable level for CT contrast however with the hydration I have actually improved from 35% and declining two years ago ... so if care is taken and proper treatment FOR YOU is begun, you may improve your renal function..... and feel better.