DOI: 10.1148/radiol.2383051019
(Radiology 2006;238:1077-1078.)
© RSNA, 2006
Gadolinium-based Contrast Media for Multi–Detector Row Spiral CT Pulmonary Angiography in Patients with Renal Insufficiency
Sameh K. Morcos, FRCS, FRCR
Department of Diagnostic Imaging, Sheffield Teaching Hospitals, Herries Road, Sheffield S5 7AU, United Kingdom
e-mail: sameh.morcos{at}sth.nhs.uk
Editor:
I read with interest the article by Dr Remy-Jardin and colleagues on the use of gadolinium-based contrast media for multi–detector row spiral computed tomographic (CT) pulmonary angiography (1), which was published in the June 2005 issue of Radiology. However, I am concerned about the suggestion of the safety of this approach in patients with underlying renal insufficiency. Gadolinium-based contrast agents are more nephrotoxic than iodinated contrast media in equivalent x-ray attenuating doses (2). This has been demonstrated in experimental animal studies and supported by clinical observations (3,4). The details of the controversy of using gadolinium-based contrast media for radiographic examinations have been presented in several reports (3–6).
The injection rate of 6 mL/sec (mean total volume, 48 mL) employed in the study by Dr Remy-Jardin and colleagues is equal to 3 mmol of gadolinium atoms per second. To produce a comparable attenuation with iodinated contrast media at the exposure setting of 120 kV would require the injection of 6 mmol of iodine atoms per second (at 120 kV, the attenuation of a gadolinium atom is approximately twice that of an iodine atom) (2). One millimole of iodine atoms per milliliter is equal to 126 mg iodine per milliliter (there are 2.38 mmol of iodine atoms per milliliter at the concentration of 300 mg iodine per milliliter) (2). The administration of 120 mg iodine per milliliter at a rate of 6 mL/sec has been reported to produce excellent-quality vascular contrast enhancement on CT pulmonary angiograms (7). A 50-mL solution of iodinated contrast medium at the concentration of 120 mg iodine per milliliter can be produced by diluting 20 mL of 300 mg iodine per millimeter nonionic monomeric contrast medium preparation with 30 mL of normal saline. This dose, which would achieve x-ray attenuation comparable with that produced with gadolinium-based contrast media, is unlikely to induce any substantial reduction in renal function, even in patients with advanced renal disease (3,8,9). Hence, there is no advantage whatsoever to using gadolinium-based contrast media for radiographic examinations in patients with renal impairment, since diluted iodinated contrast media can produce comparable attenuation with less nephrotoxicity at much lower cost (the price of 50 mL of a gadolinium-based contrast agent is at least 15 times more expensive than 20 mL of a nonionic monomeric contrast medium) (3). The use of gadolinium-based contrast media for CT pulmonary angiography is justified only in patients at high risk of serious allergy-like reaction to iodinated contrast media or when thyroid treatment with radioactive iodine is imminent (2).
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References
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- Remy-Jardin M, Dequiedt P, Ertzbischoff O, et al. Safety and effectiveness of gadolinium-enhanced multi–detector row spiral CT angiography of the chest: preliminary results in 37 patients with contraindications to iodinated contrast agents. Radiology 2005;235:819–826.[Abstract/Free Full Text]
- Thomsen HS, Almen T, Morcos SK; Contrast Media Safety Committee of the European Society of Urogenital Radiology (ESUR). Gadolinium-containing contrast media for radiographic examinations: a position paper. Eur Radiol 2002;12:2600–2605.[Medline]
- Nyman U, Elmståhl B, Leander P, Nilsson M, Golman K, Almén T. Are gadolinium-based contrast media really safer than iodinated media for digital subtraction angiography in patients with for azotemia? Radiology 2002;223:311–318.[Abstract/Free Full Text]
- Thomsen HS. Gadolinium-based contrast media may be nephrotoxic even at approved doses. Eur Radiol 2004;14:1654–1656.[Medline]
- Strunk HM, Schild H. Actual clinical use of gadolinium-chelates for non-MRI applications. Eur Radiol 2004;14:1055–1062.[CrossRef][Medline]
- Morcos SK. Prevention of contrast media-induced nephrotoxicity after angiographic procedures. J Vasc Interv Radiol 2005;16:13–23.[Medline]
- Remy-Jardin M, Remy J, Wattinne L, Giraud F. Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single breath hold technique—comparison with pulmonary angiography. Radiology 1992;185:381–387.[Abstract/Free Full Text]
- McCullough PA, Wolyn R, Rocher LL, et al. Acute renal failure after coronary intervention: incidence, risk factors and relationship to mortality. Am J Med 1997;103:368–375.[CrossRef][Medline]
- Solomon R. Contrast medium-induced acute renal failure. Kidney Int 1998;53:230–242.[CrossRef][Medline]
Response
Martine Remy-Jardin, MD, PhD
Department of Radiology, Calmette Hospital, Boulevard Jules Leclerc, Lille 59037, France
e-mail: mremy-jardin@chru-lille.fr
We thank Dr Morcos for his interest in our work (1) and for reminding radiologists that gadolinium-based contrast agents are not devoid of nephrotoxicity. However, this debate should not be opened without emphasizing that their nephrotoxicity is dependent on the dose administered to the patients. This debate is often biased by the assumption that "it should theoretically be possible to obtain radiographic images of diagnostic quality with gadolinium-based contrast agents, but the image quality will generally be inferior to that achieved with iodinated contrast agents" (2). One objective of our study was to investigate this assumption at the level of the pulmonary circulation by using multi–detector row CT in a population of patients at-risk for the administration of iodinated contrast agents. As shown in our article, we observed that the degree of enhancement within pulmonary arteries could be comparable with that achievable with iodinated contrast media. This result contradicts one important conclusion of the European Society of Urogenital Radiology's position statement on the use of gadolinium-based contrast media for radiographic examinations, according to which "the use of gadolinium-based contrast medium in approved intravenous doses up to 0.3 mmol/kg b.w. [body weight] will not give diagnostic radiographic information in most cases" (2).
Once the clinical usefulness of gadolinium-enhanced CT angiograms of the pulmonary circulation can be demonstrated, there remains the important question raised by Dr Morcos about the safety of such investigations, in particular for patients with preexisting renal insufficiency. In his letter, Dr Morcos states that gadolinium-based contrast agents are more nephrotoxic than iodinated contrast media in equivalent x-ray attenuating doses. While this is true, one should underline that our study was not designed to administer gadolinium-based contrast agents in "equivalent x-ray attenuating doses," as each patient received a dose of 0.3 or 0.4 mmol per kilogram of body weight. These doses are accepted elsewhere for magnetic resonance imaging and have been previously reported without side effects in patients with renal insufficiency (3–6). In our study, no impairment in renal function was observed, except in one patient with preexisting diabetic nephropathy who showed transient impairment of renal function after having received the dose of 0.3 mmol per kilogram of body weight. These preliminary results have been confirmed in a larger series of patients investigated with 16–detector row CT technology (7). The second comment from Dr Morcos concerns the alternative use of 50 mL of a 30% diluted iodinated contrast agent to allow the administration of a contrast agent at the concentration of 120 mg iodine per milliliter, a concentration that has already been shown to produce excellent-quality vascular contrast enhancement on CT pulmonary angiograms (8). Whereas this approach is theoretically valid in terms of concentration, it would be important to evaluate the renal consequences of such a protocol in patients with underlying renal failure. To our knowledge, no study has addressed this issue, and the statement from Dr Morcos, according to whom "this dose, which would achieve x-ray attenuation comparable with that produced with gadolinium-based contrast media, is unlikely to induce any significant reduction in renal function, even in patients with advanced renal disease," remains a hypothesis.
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References
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- Remy-Jardin M, Dequiedt P, Ertzbischoff O, et al. Safety and effectiveness of gadolinium-enhanced multi–detector row spiral CT angiography of the chest: preliminary results in 37 patients with contraindications to iodinated contrast agents. Radiology 2005;235:819–826.[Abstract/Free Full Text]
- Thomsen HS, Almen T, Morcos SK; Contrast Media Safety Committee of the European Society of Urogenital Radiology (ESUR). Gadolinium-containing contrast media for radiographic examinations: a position paper. Eur Radiol 2002;12:2600–2605.[Medline]
- Coche EE, Hammer FD, Gofette PP. Demonstration of pulmonary embolism with dynamic gadolinium-enhanced spiral CT. Eur Radiol 2001;11:2306–2309.[CrossRef][Medline]
- Prince MR, Arnoldus C, Frisoli JK. Nephrotoxicity of high-dose gadolinium compared with iodinated contrast. J Magn Reson Imaging 1996;6:162–166.[Medline]
- Swan SK, Baker JF, Free R, et al. Pharmacokinetics, safety, and tolerability of gadoversetamide injection (Optimark) in subjects with central nervous system or liver pathology and varying degrees of renal function. J Magn Reson Imaging 1999;9:317–321.[CrossRef][Medline]
- Haustein J, Niendorp HP, Krestin G, et al. Renal tolerance of Gd-DTPA dimeglumine in patients with chronic renal failure. Invest Radiol 1992;27:153–156.[CrossRef][Medline]
- Remy-Jardin M, Bahepar J, Lafitte JJ, et al. 16-slice multi–detector CT angiography of the pulmonary circulation using gadolinium-based contrast agents: prospective evaluation in 60 patients. Radiology 2005;238:000–000.
- Remy-Jardin M, Remy J, Wattinne L, Giraud F. Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single breath hold technique—comparison with pulmonary angiography. Radiology 1992;185:381–387.[Abstract/Free Full Text]
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