A system for sharing medical information among a plurality of locations, comprising: a plurality of local Picture Archiving Communication Systems, PACS, (112, 122, 132) storing patient studies, each patient study being indexed by a local patient identifier; a plurality of local patient identity registries, PIRs, (117, 127, 137) each adapted to store a local identity list including a respective global patient identifier and corresponding to local patient identifier for each of a plurality of patients having studies stored on a corresponding one of the local PACS (112, 122, 132) a plurality of local location registries, PLRs (119, 129, 139) reach adapted to store a local index of the patient studies stored on the local PACS (112, 122, 132) for each of the plurality of patients, the index including a storage location of each study and the corresponding global patient identifier; wherein the plurality of local PACS (112, 122, 132), the plurality of local PIRs (117, 127, 137) and the plurality of local PLRs (119, 129, 139) are arranged in a plurality of local PACS deployments (110, 120, 130), each local PACS deployment (110, 120, 130) comprising a respective local PACS (112, 122, 132), a respective local PIR (117, 127, 137) and a respective local PLR (119, 129, 139); a global PIR, located remotely from the local PACS (112, 122, 132), the local PIRs (117, 127, 137) and the local PLRs (119, 129, 139), adapted to store a global identity list including a global patient identifier for each patient having studies stored in the local PACS (112, 122, 132), the global patient identifier being linked with corresponding local patient identifiers; and a global PLR, located remotely from the local PACS (112, 122, 132), the local PIRs (117, 127, 137) and the local PLR (119, 129, 139), adapted to store a global index of the patient studies stored on the local PACS (112, 122, 132) for each patient, the index including a storage location of each study and the corresponding global patient identifier. a plurality of local Picture Archiving Communication Systems, PACS, (112, 122, 132) storing patient studies, each patient study being indexed by a local patient identifier; a plurality of local patient identity registries, PIRs, (117, 127, 137) each adapted to store a local identity list including a respective global patient identifier and corresponding to local patient identifier for each of a plurality of patients having studies stored on a corresponding one of the local PACS (112, 122, 132) a plurality of local location registries, PLRs (119, 129, 139) reach adapted to store a local index of the patient studies stored on the local PACS (112, 122, 132) for each of the plurality of patients, the index including a storage location of each study and the corresponding global patient identifier; wherein the plurality of local PACS (112, 122, 132), the plurality of local PIRs (117, 127, 137) and the plurality of local PLRs (119, 129, 139) are arranged in a plurality of local PACS deployments (110, 120, 130), each local PACS deployment (110, 120, 130) comprising a respective local PACS (112, 122, 132), a respective local PIR (117, 127, 137) and a respective local PLR (119, 129, 139); a global PIR, located remotely from the local PACS (112, 122, 132), the local PIRs (117, 127, 137) and the local PLRs (119, 129, 139), adapted to store a global identity list including a global patient identifier for each patient having studies stored in the local PACS (112, 122, 132), the global patient identifier being linked with corresponding local patient identifiers; and a global PLR, located remotely from the local PACS (112, 122, 132), the local PIRs (117, 127, 137) and the local PLR (119, 129, 139), adapted to store a global index of the patient studies stored on the local PACS (112, 122, 132) for each patient, the index including a storage location of each study and the corresponding global patient identifier.