Current Clinical Concerns in CT: Results : IV Contrast Administration
Choice of IV Contrast
1. I have been asked the question of whether or not it is possible to see the difference in the contrast on a 16 slice scanner, using Omnipaque 350 vs. Isovue 370. Also, is Visipaque easier to visualize than either one.
| Answer: I doubt you can tell Omni 350 and Isovue 370 apart based on density values. We use Omni 350 as it gives us excellent opacification with essentially no patient reactions (even minor ones like nausea and vomiting). And this is critical with CT angio or any MDCT application. We use Visipaque-320, it is great for PE studies as it provides an ideal contrast column minimizing flow related artifacts. |
2. I've had a discussion with the Nycomed rep and our CT radiologist and I was asked by them to email you with this question. We use Visipaque for all CTA's, and are just now starting to use them for patients with borderline creatinine. Our radiologist wanted your opinion on using Visipaque and parenchymal liver enhancement. Is it equal to Optiray 320 (the contrast that we use)? How about other areas, i.e. routine heads with contrast, necks, chest, abdomen and pelvis.
| Answer: Visipaque works great for CTA in part due to its iso-osmolar nature, which allows for homogeneous column of contrast. I see a little difference between Visipaque 320 and Omnipaque 350 in practice. It is surely in terms of opacification as good or better than Optiray 320 and then you have the additional benefits. The role of Visipaque in patients with borderline renal function is underappreciated as noted in the NEJM article last month. |
3. Until now we have only used Omni 350 for CT procedures. We now also have Visipaque 320. What is the best way to decide which type of contrast to use? Only lab levels or should age and overall health be factored in also? [This question was asked by 3 individuals]
| Answer: If not for cost, we would use only Visipaque. Our rules for Visipaque are study specific, as well as patient specific.. They include that we use Visipaque for: i. All PE studies-less flow related artifacts ii. All cardiac and coronary studies-less pulse rate change, so better CTA's iii. All gated studies iv. Borderline renal function v. Mildly decreased renal function vi. Diabetics vii. Cardiac patients viii. Whole body screening ix. Recently received contrast x. Older patients, especially with any co-morbid factors |
4. We are considering a change of vendor for our IV contrast, from Omnipaque 350 to Ultravist 370. Are you aware of any significant differences in terms of adverse reactions, degree of enhancement, injection difficulty, etc, between these two agents.
| Answer: Our experience with Ultravist was a marked increase in minor (nausea and vomiting) reactions. The enhancement is similar, etc., but our safety profile for Ominipaque seemed far superior and we are big fans of Omnipaque 350 and Visipaque 320. On what basis are you considering change? Have you tried Ultravist yet? Let us know. |
5. Does Visipaque, along with a steroid prep, lower the chances of a contrast reaction? This is opposed to Omnipaque with a steroid prep, on patients with a history of contrast induced reactions. The reason I ask is because we had a patient that had a previous contrast reaction to Omnipaque with a steroid prep. We chose not to give the patient IV contrast in this case, but I was wondering for future reference.
| Answer: If someone has had a breakthrough on a steroid prep, we would do our best to find an alternative study, because of the potential for a breakthrough (up to 25%). If they need a CT, then we would balance the risk and reward, and proceed with caution. |
References
Aspelin P, Aubry P, Fransson S-G et al. Nephrotoxic effects in high-risk patients underging angiography. NEJM 2003; 348(6): 491-9.
- Summary: This study involved 129 diabetic patients with serum creatinine levels of 1.5 to 3.5 mg per deciliter who were randomized to receive low-osmolar, nonionic monomeric iohexol or iso-osmolar, nonionic, dimeric iodixanol during coronary or aortofemoral angiography. The creatinine was measured for 3 days following the procedure, and compared to baseline. Results showed a significantly lower mean peak increase in creatinine from day 0 to 3 in the iodixanol group, The mean change in the creatinine concentration from day 0 to day 7 was significantly lower in the iodixanol group as well. A higher incidence of adverse events was noted in the iohexol group, including serious events related to contrast medium.
Letters to the Editor: Nephropathy induced by contrast medium NEJM 2003; 348; 22: 2257-2259.
- Summary: The following are comments with respect to the study by Aspelin et al, referenced above, in the form of letters to the editor in the NEJM.
- More than twice as many patients in the iohexol group had proteinuria compared to the iodixanol group.
- The patients' renal function in both groups was not considered severely impaired.
- The measurement of serum creatinine level as the outcome variable does not equate with "clinically important adverse effects."
- The duration of diabetes was different for the 2 groups.
Chalmners N, Jackson RW. Comparison of iodixanol and iohexol in renal
impairment. British Journal of Radiology 1999; 72: 701-703.
- Summary:In this prospective, randomized study, patients were administered
isosmolar iodixanol (nonionic dimer) to a nonionic monomer (iohexol).
Fifty-four patients with a median baseline creatinine of 269.5 were
given a mean dose of 60 mL of iodixanol. Forty eight patients with a
median baseline creatinine of 295 were given a mean dose of 52.5 mL of
iohexol. Creatinine levels were measured subsequent to angiography. In
the iohexol group, 31% of patients had a creatinine increase of greater
than 10%, and 10% of patients had a craetinine rise of more than 25%.
For comparison to 15% of the iodixanol group had a creatinine increase
of more than 10%, and 3.7% had an increase in creatinine of more than
25%. The incidence of creatinine increase greater than 10% was
statistically lower with iodixanol. In either group, the increase in
creatinine correlated with the dose of contrast. The authors conclude
that nephrotoxicity may be slightly lower with iodixanol compared to
iohexol.
Carraro M. Malalan F. Antonione R. Stacul F. Cova M. Petz S. Assante M.
Grynne B. Haider T. Palma LD. Faccini L. Effects of a dimeric vs a
monomeric nonionic contrast medium on renal function in patients with
mild to moderate renal insufficiency: a double-blind, randomized
clinical trial. European Radiology. 1998; 8(1):144-7.
- Summary: In this study of patients undergoing IV urography, patients
with mild to moderate renal insufficiency were imaged with either
iodixanol (nonionic dimer) or iopromide (nonionic monomer). The dose
was 148 +/- 21.3 mL for iodixanol 320 mgI/mL and 153+/- 24 mL for
iopromide 300 mgI/mL. The serum creatinine, urinary enzymes
alanylaminopeptidase and N-acetyl-B-glucosaminidase, as well as urinary
alpha-1-microglobulin and albumin levels were evaluated prior to the
study and at 1h, 6h, 24h, 48h and 7 days following. Comparison showed
no significant difference in urinary enzymes or serum creatinine. One
patient who received iodixanol developed transient contrast induced
nephropathy. The authors concluded that both agents had
a low nephrotoxic potential in patients with mildly to moderately
impaired renal function.