Nephrogenic systemic fibrosis and contrast medium-induced nephropathy: a choice between the devil and the deep blue sea for patients with reduced renal function?

Abstract

More than 31⁄2 years ago, a potential link between exposure to gadolinium-based contrast agents (GdCA) and the development of nephrogenic systemic fibrosis (NSF) was proposed (1, 2). Since then, daily radiologic practice has changed. Some radiologists refuse to give patients with a glomerular filtration rate (GFR) below 30 or 60 ml/min/1.73 m an enhanced magnetic resonance imaging (MRI) examination and refer them to enhanced computed tomography (CT). Others just do an unenhanced MRI, while several radiologists do enhanced MRI with a more stable agent (e.g., macrocyclic agents) when the unenhanced images or the clinical history indicate the need for administration of a Gd-CA. Only very few continue the practice as if they had never heard of NSF and the stability of various GdCA. The real consequences of transferring a patient with reduced renal function from enhanced MRI to enhanced CT are seldom discussed, and the issue is not without its problems. It seems as if no one advocates any longer the use of Gd-CA for conventional X-ray and CT, in order to protect the kidneys from contrast-induced nephropathy (CIN). Therefore, this issue is not discussed in the current editorial. In the workup of several diseases, CT is inferior to MRI from a diagnostic point of view. In particular, when it comes to the central nervous system (CNS), the spine, and osteoarticular pathology, MRI is superior (3). Also, within the abdomen, enhanced MRI has some advantages compared to enhanced CT. Thus, transfer to enhanced CT in fear of NSF may expose the patient to an inferior diagnostic workup. Recently, a case was presented to us by a Scandinavian colleague. A patient was referred to CT urography due to a single episode of macroscopic hematuria. The doctor in charge of the CT scanner refused to give the patient an iodinebased contrast agent (I-CA) because of the increased risk of CIN, and referred the patient to enhanced MRI. The patient had chronic kidney disease stage 5 but was not yet on replacement therapy. The doctor at the MR unit also refused to give the patient an enhanced examination, but this time because of the risk of NSF. There were some calcifications in the left pelvic cavity, and the unenhanced scans were reported as showing pelvic stones. Four months later, the patient returned after a new episode of macroscopic hematuria. This time, enhanced MRI was performed. It revealed that it was not pelvic stones, but a urothelial tumor with calcifications in the pelvic cavity. However, this time, the patient also had metastases from the urothelial tumor. Thus, it is not appropriate any longer to talk about CIN and NSF; ‘‘metastases’’ (delay of diagnosing a malignant lesion) have to be included as a third alternative. Radiation from the CT scanner is also an issue, particularly in young patients who have a higher risk of developing a solid cancer from the radiation than older patients (4). Thus, in young patients, this must also be taken into consideration. Severe anaphylactoid-like reactions are believed to occur more frequently after I-CA than after GdCA (5). However, comparative studies have never been performed. Recently, an American colleague drew our attention to a case. The patient had chronic kidney disease stage 4 or 5. She was referred from enhanced MRI to enhanced CT due to fear of NSF; the department had decided no longer to give Gd-CA to patients with a glomerular filtration rate below 30 ml/min/1.73 m. During the injection of the I-CA, the patient had an anaphylactoid-like reaction that required instant treatment. The patient did not survive the acute non-renal adverse reaction. Recent surveys have shown that radiologists and technicians are often not prepared for such events (6, 7). They do not know where the adrenalin ACTA RADIOLOGICA