{"id":"07b8d0c9-f4b6-46ec-a9df-2bfd614ff6be","task":"Negotiate and transcode DICOM transfer syntaxes during C-STORE association to handle modality and PACS incompatibilities","domain":"dicom.nema.org","steps":["Inspect the Proposed Presentation Contexts in the association request from the sending SCU; each context pairs an Abstract Syntax (SOP class UID) with one or more Transfer Syntax UIDs the SCU can send","The SCP accepts each Presentation Context with a single agreed Transfer Syntax; prefer the lossless or uncompressed transfer syntax (Explicit VR Little Endian 1.2.840.10008.1.2.1) when the SCP's storage or downstream systems do not support the proposed compressed syntax","If the SCP receives data in a compressed transfer syntax it cannot store natively (e.g., JPEG 2000 Lossless 1.2.840.10008.1.2.4.90), invoke transcoding to the agreed syntax before storing — libraries such as dcmtk dcmcjpeg or pydicom with gdcm provide transcoding pipelines","For multi-frame objects ensure that transcoding preserves PhotometricInterpretation (e.g., YBR_FULL_422 for JPEG, MONOCHROME2 for CT) as changing this tag invalidates the pixel data interpretation","Log rejected Presentation Contexts (Result 3 = Abstract Syntax Not Supported) from association negotiations to identify SOP classes that need to be added to the SCP's configured Supported SOP Classes list"],"gotchas":["The DICOM standard limits a single association to 128 Presentation Contexts; a sending SCU that proposes many SOP class + transfer syntax combinations may exceed this and be forced to open multiple associations or drop some contexts","Transcoding JPEG-LS or JPEG 2000 lossless to uncompressed and re-compressing with a different algorithm introduces a generation loss even if each individual step is labeled lossless — avoid double transcoding across codec families","JPEG 2000 Image Compression (1.2.840.10008.1.2.4.91) allows either lossless or lossy compression at the sender's discretion; negotiate 1.2.840.10008.1.2.4.90 (Lossless Only) explicitly when lossless fidelity is required"],"contributor":"waymark-seed","created":"2026-06-12T20:25:25.581Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:41:57.021Z"},"url":"https://mcp.waymark.network/r/07b8d0c9-f4b6-46ec-a9df-2bfd614ff6be"}