LAUSR

The fear of using linear-type GBCAs has spread rapidly among Japanese radiologists since the first report suggesting a higher risk of deposition of linear-type GBCAs [1]. Moreover, according to the medical information and technology service company, IMS Japan, the usage of lineartype GBCAs in Japan is declining rapidly. The product sales (units) of pre-filled syringes of linear-type GBCAs as a percentage of both types (linear and macrocyclic) declined rapidly by 2016: 64.7% in 2014, 54.7% in 2015, and 24.7% in 2016 (Fig. 1) [4]. The primary reason for avoiding the use of linear-type GBCAs is likely based on the concern that unknown symptoms and adverse effects may develop in the future. In view of this uncertainty, will the government and pharmaceutical companies take responsibility if the deposition of gadolinium on the brain leads to symptomatic side effects? The responsibility may be assigned to physicians continuing to use linear-type GBCAs while being cognizant of the fact they are associated with higher risk of deposition than macrocyclic GBCAs. Therefore, it is natural to avoid the use of linear-type GBCAs, even if no symptoms manifest in the future. However, whether this preventive measure is appropriate or excessive remains to be determined.