A system for sharing medical information among a plurality of locations, comprising: a plurality of local Picture Archiving Communication Systems, PACS, storing patient studies, each patient study being indexed by a local patient identifier; a plurality of local patient identity registries, PIRs, 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 a plurality of local location registries, PLRs reach adapted to store a local index of the patient studies stored on the local PACS 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 , the plurality of local PIRs and the plurality of local PLRs are arranged in a plurality of local PACS deployments , each local PACS deployment comprising a respective local PACS , a respective local PIR and a respective local PLR ; a global PIR , located remotely from the local PACS , the local PIRs and the local PLRs , adapted to store a global identity list including a global patient identifier for each patient having studies stored in the local PACS , the global patient identifier being linked with corresponding local patient identifiers; and a global PLR , located remotely from the local PACS , the local PIRs and the local PLR , adapted to store a global index of the patient studies stored on the local PACS 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, storing patient studies, each patient study being indexed by a local patient identifier; a plurality of local patient identity registries, PIRs, 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 a plurality of local location registries, PLRs reach adapted to store a local index of the patient studies stored on the local PACS 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 , the plurality of local PIRs and the plurality of local PLRs are arranged in a plurality of local PACS deployments , each local PACS deployment comprising a respective local PACS , a respective local PIR and a respective local PLR ; a global PIR , located remotely from the local PACS , the local PIRs and the local PLRs , adapted to store a global identity list including a global patient identifier for each patient having studies stored in the local PACS , the global patient identifier being linked with corresponding local patient identifiers; and a global PLR , located remotely from the local PACS , the local PIRs and the local PLR , adapted to store a global index of the patient studies stored on the local PACS for each patient, the index including a storage location of each study and the corresponding global patient identifier. <EOS>