Musculoskeletal CT

What it does

Musculoskeletal CT reads CT of the pelvis, acetabulum and limbs, the scans ordered for complex fractures, for planning their fixation and for characterising a bone lesion. The run segments every bone in the field of view, together with any implant, and exports each one as a surface mesh that planning software and 3D printers can open.

On those masks it detects fractures, splits each fractured bone into labelled fragments and measures their displacement, which turns a stack of axial slices into a fragment map a surgeon can rotate. Focal bone lesions are found, described as lytic, sclerotic or mixed with their aggressiveness features, and given the management category of Bone-RADS.

Intended use

Decision support and planning input for orthopaedic and trauma surgeons and for the emergency physicians who see these injuries first: where the fracture runs, how many fragments there are and how far they have moved. For incidental bone lesions it supplies a structured, guideline-based next step.

Who it is for

Orthopaedic trauma surgeons, pelvic and acetabular surgeons, hand and foot surgeons, musculoskeletal radiologists, emergency physicians and 3D-printing labs in hospitals. Developers use the meshes and fragment labels in surgical planning, patient-specific guide or implant design software.

Accepted input

• Regions: pelvis and acetabulum, and the upper and lower extremities; the pelvis of a trauma pan-scan is read as well.
• NIfTI with explicit spacing is accepted for the bone segmentation.

Requirements

Requirement	Why
Thin slices	Surface meshes and fragment boundaries follow the voxel size; thick slices are flagged for partial volume
Rescale Slope and Intercept	Bone, metal and lesion matrix are separated in Hounsfield units
The whole bone of interest in the field of view	A fragment map needs every fragment

Metal artefact from implants, nutrient canals and open growth plates in children are known mimics and are flagged where they affect a finding.

Optional context

The mechanism of injury, known implants or previous surgery, a history of cancer and the clinical question (fracture work-up, surgical planning, incidental lesion) go in clinical_context and shape the guidance.

The result

A sectioned JSON result, with DICOM SEG masks of bones, fragments, implants and lesions, and STL meshes of the segmented bones and implants.

Section	Content
Fractures and fragments	Fracture detection, fragment segmentation and labels, displacement between fragments
Bones and implants in 3D	Masks of the pelvis, femur, humerus, scapula, ribs, extremity bones and implants, with STL surface meshes
Bone lesions	Focal lesions with segmentation, lytic, sclerotic or mixed pattern, aggressiveness features and Bone-RADS category
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

Standards

• DICOM: SEG for bones, fragments, implants and lesions; SR TID 1500 Measurement Report for displacement and lesion size; key images, Encapsulated PDF and FHIR DiagnosticReport.
• 3D exports: STL surface meshes of bones and implants for planning software and 3D printing.
• Reporting system: Bone-RADS v2023 for incidental and indeterminate bone lesions on CT.