Lateral center-edge angle on conventional radiography and computed tomography

Area of Science:

• Orthopedic imaging
• Radiology
• Hip biomechanics

Background:

• The lateral center-edge angle (LCEA) is crucial for assessing hip joint stability.
• While traditionally measured on AP radiographs, its use in CT-based studies is increasing.
• Reliability and correlation of CT-based LCEA with radiographic measurements require investigation.

Purpose of the Study:

• To evaluate the interobserver and intraobserver reliability of LCEA measurements on AP radiographs.
• To determine the interobserver and intraobserver reliability of LCEA measurements on CT scans.
• To assess the intermodality correlation of LCEA between CT scans and AP radiographs.

Main Methods:

• Retrospective review of AP radiographs and CT scans from 22 patients with slipped capital femoral epiphyses.
• CT scans were reoriented to a neutral pelvic tilt and inclination.
• Three evaluators measured LCEA on unaffected hips using corresponding AP and CT coronal images.

Main Results:

• High interobserver reliability for LCEA: 0.84 (AP radiographs) and 0.88 (CT scans).
• Excellent intraobserver reliability for LCEA: 0.96 (AP radiographs) and 0.98 (CT scans).
• Good intermodality correlation between CT and AP radiographs (ICC = 0.79).

Conclusions:

• LCEA measurements on CT scans demonstrate high reliability.
• CT-based LCEA measurements correlate well with those from AP radiographs.
• CT is a reliable modality for LCEA assessment in hip imaging.