Purpose: This study sought to compare high-resolution ultrasonography (HRUS) without and with compound imaging in evaluating the injured posterior cruciate ligament (PCL).
Materials and methods: Thirteen patients with a magnetic resonance imaging (MRI) diagnosis of PCL lesions (ten acute and three chronic) and 20 healthy controls underwent conventional and compound HRUS performed by the same radiologist who was blinded to the subjects' case-control status. The PCL was scanned in a longitudinal direction in all cases. HRUS images were assessed for PCL thickness by two other radiologists blinded to the number and type of PCL injury. PCLs were classified as normal or injured, and the latter as having acute or chronic injuries. Inter-method reproducibility of measuring PCL thickness was assessed on conventional and compound HRUS images.
Results: Complete agreement in classifying normal or injured PCL and acute or chronic PCL injuries was achieved. PCL thickness in volunteers was 4.5+/-0.7 mm on conventional images and 4.6+/-0.7 mm on compound images. On conventional and compound HRUS images, the thickness of acutely injured PCL was 9.1+/-1.5 mm and 9.2+/-1.7 mm, respectively, and that of chronically injured PCL was 7+/-0.9 mm and 7+/-0.8 mm. Inter-method reproducibility of PCL thickness measurements on conventional vs. compound HRUS images was 98.6%.
Conclusions: HRUS is a reliable technique for studying the PCL and detecting PCL injuries.