부산대학교 도서관

Ultra-high-field (UHF) magnetic resonance imaging (MRI) can open up new avenues in clinical diagnosticimaging. Its sensitivity can be further improved using contrast agents (CAs). Therefore, developing low-molecular-weight MR CAs that are efficient under UHF is crucial to ensure taking full advantage of MRimaging at UHF. Moreover, designing highly stable UHF liver-specific CA has been challenging. Here, usingdysprosium (Dy3+), which relaxes water protons via a Curie relaxation that increases T2 relaxationsubstantially with the magneticfield strength, we report a new macrocyclic liver specific Dy3+ complex(Dy[DO3A-EOB]). We observed a 7.06 times higher r2/r1 ratio of Dy[DO3A-EOB] at 9.4 T than that of 1.5 T,which suggests a superior negative-enhancing MR CA at UHF. In vivo MR imaging results furtherdemonstrated that Dy[DO3A-EOB] showed a much strong negative enhancement at UHF (9.4 T) thanunder a lowfield (1.5 T). It was also found that, in addition to the ligand structure, the metal itself plays animportant role in determining the liver uptake pattern of the CA. Therefore, we successfullydemonstrated thefirst example of a small-molecular-weight liver-specific Dy3+ complex acting as aT2 CA with high sensitivity at UHF for diagnosis of liver diseases.