Cartilage diameter evaluation is critical for cartilage assessment. Magnetic resonance imaging (MRI) is the gold standard tool
in cartilage evaluation. This observational and analytical study was designed to answer the question of whether there is a
relationship between MRI and ultrasound in measuring cartilage thickness in the medial femoral condyle. The current study was
conducted at the Radiology Department of Rasole-Akram Hospital, Tehran, Iran, between March and May 2020. The sample
size was 18 people. The mean cartilage thickness of the left medial femoral cartilage was measured by T1 weighted MRI and
ultrasound from transverse, anterior, middle, and posterior medial femoral regions in nine healthy females with a mean ± std
deviation as indicated below: thickness = 1.6 ± 0.04 m, weight = 55.3 ± 4.3 kg, age = 21.7 ± 0.8 years.
Additionally, nine healthy males with thickness = 1.80 ± 0.02 m, weight = 78.6 ± 11.1 kg, age = 22.4 ± 0.7 years were also
included. Pearson and Bland–Altman plots were used for correlations and agreements. Anterior longitudinal ultrasound
thickness measures were significantly positively correlated with MRI anterior (r = 0.93, p = 0.00001), transverse ultrasound
with MRI anterior (r = 0.87 p = 0.0369), middle longitudinal ultrasound with MRI anterior (r = 0.87 p = 0.00002), and transverse
ultrasound and MRI middle (r = 0.87 p = 0.00001).
Agreement in all aspects was good except between the anterior longitudinal ultrasound and MRI posterior. There was a good
absolute agreement between corresponding measurements done by ultrasound and MRI. The results suggest that ultrasound may
be a good clinical tool for assessing relative cartilage thickness in medial femoral regions.