Radiographic Evaluation of Congenital and Acquired Foot Deformities Calcaneal Pitch

Purpose	Characterization of congenital and acquired foot deformities on radiographs
Tag(s)	bilateral foot, foot, x-rays, radiographs, congenital foot, pes, feet, calcaneal pitch, weight-bearing
Panel	Pediatric
Define-AI ID	21010014
Originator	Pediatrics Panel
Lead	Viet Le & Alex Towbin
Panel Chair	Steven Blumer
Panel Reviewers	Pediatric Panel
License	Creative Commons 4.0
Status	Public Comment
RadElement Set	RDES203

Clinical Implementation

Value Proposition

Multiple angles and measurements can be used to evaluate abnormal development of the foot, but the task of obtaining these can be cumbersome and time-intensive. An automated method for obtaining a series of angle measurements and bony relationships, which can eventually be used to characterize foot deformities, should improve the radiologists’ workflow.

For our use case(s), we will first focus on automating measurement of a series of different angles and bony associations on foot radiographs, which can then be compiled to determine the presence vs. absence of a foot deformity. If present, our hope is for the algorithm to further diagnose/characterize the specific foot deformity. Ultimately, this may be expanded to include additional modalities, such as CT.

For this particular use case, we will limit our evaluation to measuring the calcaneal pitch. Additional use cases include the AP and lateral talocalcaneal angles, talo-1st metatarsal angle, talonavicular axis, 1st metatarsophalangeal angle, Meary’s angle, and the tibial-calcaneal angle.

Narrative(s)

3 year-old female presents to the pediatrician with abnormal gait and in-toeing. Bilateral, weight-bearing 3-view foot radiographs are obtained for evaluation of foot deformities.

6 month-old male presents for contractures/abnormal positioning of the feet. Bilateral, 3-view simulated weight-bearing foot radiographs are obtained for evaluation of foot deformities.

Workflow Description

Radiographs of the foot/feet are ordered, obtained, sent to PACS and the algorithm is triggered.

The algorithm delivers the following outputs: calcaneal pitch, and normal vs. abnormal pitch

Considerations for Dataset Development

Procedures	X-ray, Foot Radiograph, Foot
Gender	Male, Female
Age (years)	0-18
Views	Lateral
Technique	Weight-bearing,Simulated weight-bearing or Erect
Anatomy	Foot
Confounders	Cast, Splint, Brace, Non-weight-bearing, Supine

Technical Specifications

Input

DICOM Study

Procedure	X-ray, Foot Radiograph
Views	Lateral
Data Type	DICOM
Modality	X-ray
Body Region	Lower Extremity
Anatomic Focus	Foot

Primary Outputs

Calcaneal Pitch

RadElement ID	RDE1337
Definition	The angle between the calcaneal inclination axis and the supporting horizontal surface on a weight-bearing AP foot radiograph.
Data Type	Numerical
Value Set	0-90
Units	Degrees

Secondary Outputs

Normal vs. Abnormal

RadElement ID	RDE1338
Definition	Normal for calcaneal pitch is between 20-30 degrees.
Data Type	Categorical
Value Set	normal (20-30 degrees) abnormal (<20 degrees or >30 degrees)
Units	N/A

Pes Planus vs. Pes Cavus

RadElement ID	RDE1339
Definition	Calcaneal pitch measurement can determine a pes planus or pes cavus
Data Type	Categorical
Value Set	low pitch/pes planus (<20 degrees) high pitch/pes cavus (>30 degrees)
Units	N/A

Future Development Ideas

As mentioned in the Value Proposition, future development ideas include

Additional angle measurements
Bony relationships in the foot
Diagnosis of foot deformities if present (“diagnostic use cases”)
Improvement from prior studies if comparisons are available
Extrapolation to another imaging modality, such as CT