Role of High Frequency Ultrasound in Assessment of Acute and Chronic Muscle Injuries in Comparison to MRI

Abstract Background The most common mechanism of injury of muscles is related to muscle strain (indirect muscle injury), mainly in the lower limbs. Muscles are at risk for disruption during eccentric contraction, as the force of active contraction is added to the passive stretching force applied to the myotendinous junction (MTJ). Although clinical examinations remain very important, it has been shown that radiological findings can aid clinicians in the initial assessment. Objective To evaluate the accuracy and specificity of high frequency ultrasound in identification and characterization of acute and chronic muscle injuries in comparison with MRI. Methods This ultrasonography & cross sectional study was done in private radiological centers with a period of 24 months on a random sample of 30 patients. Our study included 30 patients complaining of traumatic acute and chronic muscle injuries, 26 males (86.7%) and 4 females (13.3%), ranging in age from 18 to 55 years with a mean age of 37.5 years. Results The accuracy, sensitivity & specificity of ultrasound in detecting all muscle injuries in comparison to MRI: 86.7%, 87.5% & 83.3% respectively. The accuracy, sensitivity & specificity of ultrasound in detecting acute muscle injuries in comparison to MRI: 66.7%, 66.7 % & 66.7% respectively. The accuracy, sensitivity & specificity of ultrasound in detecting chronic muscle injuries in comparison to MRI: 95.2%, 94.4% & 100% respectively. Conclusion Ultrasound is highly operator dependent, useful for diagnosis of chronic muscle injury in comparison to the MRI, yet with pitfalls in acute muscle injuries, yet the ultrasound classification criteria for muscle injury can be used to predict the severity of injury and guide decision on the type of treatment and MRI is still considered the main diagnostic tool for muscle injuries and classification.