Bilateral Dynamic CT for Scapholunate Instability: Toward Personalized, Protocol-Standardized Kinematic Diagnosis

Area of Science:

• Orthopedic imaging
• Diagnostic radiology
• Biomechanics of the wrist

Background:

• Dynamic CT is used for 3D wrist motion assessment and diagnosing scapholunate (SL) ligament injuries.
• Institutional protocol variations hinder standardization and comparability in SL injury diagnosis.
• Bilateral scanning with contralateral referencing is explored as a diagnostic aid.

Purpose of the Study:

• To evaluate contralateral referencing in bilateral dynamic CT for SL injury diagnosis.
• To assess the impact of scan protocol variations on SL distance (SLD).
• To compare wrist motion symmetry in healthy individuals and patients with SL injuries.

Main Methods:

• Retrospective multicenter study using dynamic CT data from healthy individuals and patients with unilateral SL lesions.
• Bilateral scanning was performed on patients with confirmed unilateral SL injuries.
• Scapholunate distance (SLD) was automatically extracted and compared during dynamic wrist motion.

Main Results:

• Scan protocol variations caused minor SLD offsets (0.5 mm), especially during radial-ulnar deviation.
• Healthy contralateral wrists of patients exhibited motion similar to healthy volunteers.
• Total SL injuries showed increased SLD (up to 2.0 mm) in the injured wrist compared to the contralateral side; partial lesions showed smaller asymmetries.

Conclusions:

• Contralateral referencing in bilateral dynamic CT is feasible and supports diagnosing unilateral total SL injuries.
• This approach negates the requirement for external reference datasets.
• Bilateral dynamic CT with contralateral referencing is recommended for SL injury diagnosis.