Lateral Cephalogram

What it does

Lateral Cephalogram traces the lateral cephalometric radiograph used for orthodontic and orthognathic planning. Upload one cephalogram; the run calibrates the image scale, places the hard- and soft-tissue landmarks (up to 38) with a confidence for each, and computes the cephalometric analyses from them.

The result gives the skeletal class from ANB and the Wits appraisal, the dental relationships and growth pattern, and the cervical vertebral maturation (CVM) stage read from the second to fourth cervical vertebrae, which tells the orthodontist where the patient is on the growth curve.

Intended use

Orthodontic decision support: the tracing a clinician would otherwise do by hand, with the same landmark definitions every time, so that measurements are comparable between visits and between clinicians. Growth stage helps time functional treatment. Every value traces to the landmarks it was measured from.

Who it is for

Orthodontists, orthognathic and maxillofacial surgeons, paediatric dentists and orthodontic residents. Developers add automated tracing to orthodontic software, aligner workflows or teaching tools.

Accepted input

• DICOM: lateral cephalograms as Digital X-Ray (DX) or Computed Radiography (CR) images.
• Image exports: JPEG or PNG exported from the imaging software, accepted with a calibration warning.
• One lateral cephalogram per request, from a child, adolescent or adult patient.

Requirements

Requirement	Why
Scale calibration from the Estimated Radiographic Magnification Factor, pixel spacing or a visible ruler	Linear measurements in millimetres depend on it; without it only angles are reliable
C2 to C4 vertebrae in the image	The CVM stage is read from their shape
Soft-tissue profile visible	Needed for the soft-tissue landmarks
A lateral projection	The landmark set and the analyses are defined on the lateral view

Bilateral structures such as the mandibular border often project as double contours, and landmarks there carry a lower confidence and a flag. Missing calibration is flagged as well.

Optional context

Age, sex and the clinical question (growth assessment, orthodontic diagnosis, orthognathic planning) go in clinical_context. The analyses wanted can be named; otherwise the standard set is returned.

The result

A JSON result with landmark coordinates in millimetres and pixels, the analyses computed from them, and an overlay of the tracing on the original image.

Section	Content
Cephalometric landmarks	Up to 38 hard- and soft-tissue landmarks with coordinates and a confidence per point
Cephalometric analyses	Angles and distances for Steiner, Ricketts, McNamara, Downs, Tweed, Wits and Björk–Jarabak; skeletal class I, II or III, dental class and growth pattern
CVM stage	Cervical vertebral maturation stage CS1 to CS6 from the C2–C4 vertebrae
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

• Analyses: Steiner, Ricketts, McNamara, Downs, Tweed, Wits appraisal and Björk–Jarabak; skeletal class from ANB and Wits.
• Growth: cervical vertebral maturation stages CS1–CS6 (Baccetti).
• DICOM and exchange: landmarks and measurements in SR TID 1500, tracing overlay as GSPS, Encapsulated PDF and FHIR R4 Observations.

Related tools

• dental/ceph/analysis: move landmarks and recompute every analysis, the skeletal class and the growth pattern from the corrected points.