Known or Highly Suspected Central Nervous System (CNS) Lesion

This is an operationally combined Phase 2/3 study, which will be conducted and evaluated in 2 distinct parts: * Phase 2: Prospective, adaptive, multicenter, non-randomized, single-blind, dose-finding, including participants with known or highly suspected lesions of the CNS. The aim of the Phase 2 part is to identify an optimized dose of mangaciclanol for the Phase 3 part of the study. * Phase 3: Prospective, multicenter, randomized, controlled, single-blind, cross-over, including participants with known or highly suspected lesions of the CNS or body. The aim of the Phase 3 part is to further evaluate the efficacy and safety of mangaciclanol-enhanced MRI for the detection and characterization of lesions of the CNS or body. The investigational medicinal products (IMPs) used during the trial are mangaciclanol and gadobutrol (comparator IMP). Primary and key secondary efficacy analyses will be based on independent central blinded image evaluation (BIE), and Phase 2 data will be analyzed prior to commencement of Phase 3.