The Efficiency of Gray-Level Ultrasound Histogram Analysis in Patients with Supraspinatus Tendinopathy

Musculoskeletal ultrasonography is a viable substitute for magnetic resonance imaging (MRI) that offers advantages in terms of time efficiency and cost-effectiveness. The gray-level histogram is a tool used to depict the distribution of pixel gray levels that provide quantitative data.

The objective of our research was to establish a threshold value for ultrasonography-measured supraspinatus tendon gray-level values by comparing patients with tendinopathy to those without.

This study comprised a cohort of 271 individuals, consisting of 124 patients diagnosed with supraspinatus tendinopathy and 147 cases without the aforementioned condition who underwent shoulder MRI and ultrasound examinations. Two radiologists independently conducted the gray-level histogram analyses. The histogram parameters were determined, including the mean, minimum, median, maximum, fifth, 10th, 25th, 50th, 75th, 90th, and 95th percentiles, as well as skewness, kurtosis, and variance. The interobserver agreement was evaluated using the interclass correlation coefficient.

The supraspinatus tendinopathy group's all gray-level values were lower than those of the control group, and the difference was statistically significant (P < .05). The supraspinatus tendinopathy group exhibited greater values of skewness and kurtosis in comparison to the control group (P < .05). The area under the curve of the 95th percentile of the gray-level value was the highest (area under the curve = 0.960; cut-off value = 82.5; sensitivity = 96.7%; specificity = 88.2%).

The analysis of the histogram of gray-level values has the potential to be a promising method for the monitoring of patients with supraspinatus tendinopathy. This approach could be considered a feasible alternative to MRI.