Reply to the Letter to the Editor: “The effect of abolishing instructions to fast prior to contrast-enhanced CT on the incidence of acute adverse reactions”

Authors: Tsushima Y, Seki Y, Nakajima T, Hirasawa H, Taketomi-Takahashi A, Tan S, Suto T

Dear Editor-in-Chief,

We are thankful for the interest in our article [1]. Things assumed beneficial and safe for many years are sometimes later found to be inappropriate or even harmful. A good example would be nephrogenic systemic fibrosis (NSF) with gadolinium-based contrast agents (GBCA). It is humbling to remember that the relationship between NSF and GBCA was not first noted by the radiologist who administers GBCAs on a daily basis, but the nephrologist [2].

Fasting before administration of contrast agents has been practiced for many years without careful examination of its significance. Even after the guidelines were changed [3], many diagnostic radiologists and technologists were still worried about the strategy change. It is often difficult to change long-standing habits.

Radiology departments require safety management specific to radiology in addition to managing general medical safety. Of first and foremost importance, there is radiation dose management, and there is also consideration for safe use of contrast agents and prevention of communication errors regarding diagnostic imaging reports [4]. Meticulous safety management of contrast agent use is particularly important, because of its potential for serious adverse effects (the worst outcome being, of course, patient death) while having only diagnostic (and not therapeutic) value. A Japanese injector manufacturer, with a 90% market share in Japan, pays special attention to medical safety. Their system using radio frequency identifiers (RFID) to prevent misadministration of contrast agents is an excellent effort. The RFID affixed to the pre-filled syringe contains data such as product name, iodine concentration, volume, and expiration date. The injectors automatically read and display this information beside the CT console. If the expiration date has passed or the syringe has already been used (empty syringe), an alarm will appear, and the injector stops automatically.

The test to guarantee compatibility between the injectors and pre-filled syringes of iodinated contrast agents are carried out by contracts between this injector manufacturer and individual pharmaceutical companies. We have heard that this burden is excessive for pharmaceutical companies producing low-cost generic contrast agents, and as a result, most generic pre-filled iodinated contrast agents do not officially guarantee compatibility with these injectors. (The cost of adopting RFID is also a heavy burden for companies producing generic contrast agents, and most have not been able to adopt them despite their importance.) The Japanese government recommends the use of generic products to reduce medical costs, but due to these circumstances, most pre-filled iodinated contrast agents are virtually impossible to use in many facilities in Japan. We suspect that the official medical fee approved by the Japanese government does not consider the cost of officially guaranteeing compatibility with the power injectors in popular use. Many Japanese radiologists are dissatisfied with this situation, but to date we have not heard that the authorities are considering any alleviating measures.


[1] Tsushima Y, Seki Y, Nakajima T et al (2020) The effect of abolishing instructions to fast prior to contrast-enhanced CT on the incidence of acute adverse reactions. Insights Imaging 11(1):113.
[2] Grobner T (2006) Gadolinium–a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenic systemic fibrosis? Nephrol Dial Transplant. 21(4):1104-8. doi: 10.1093/ndt/gfk062. Epub 2006 Jan 23. Erratum in: Nephrol Dial Transplant 21(6):1745. PMID: 16431890.
[3] European Society of Urogenital Radiology. ESUR guidelines on contrast media ver. 10.0.
[4] Tsushima Y, Hirasawa H, Wakabayashi Y et al (2020) Possible solution for the problem of unread image interpretation reports: the “Gunma University Star Search”. Jpn J Radiol 38(7):643-648.