Abstract

Introduction: With increased incidence of sports injuries the practice of musculoskeletal ultrasound is gaining wide popularity outside the traditional radiology practice. Use of musculoskeletal ultrasound other than for sports injuries includes evaluation of musculoskeletal soft tissue pathologies. Ultrasonography is a non-invasive, readily available, safe, low cost and a patient comfortable modality. Application of high resolution USG in soft tissue pathologies of musculoskeletal system has evolved exponentially in the past two decades and is useful in not only evaluating the nature of soft tissue swellings but also aids in detection of histology in mostly all cases. We undertook this study to analyze the accuracy of USG in diagnosing soft tissue musculoskeletal pathologies.

Materials and Methods: This was a prospective study conducted in the Department of Radiodiagnosis of a tertiary care medical college situated in an urban area. 200 subjects with superficial soft tissue swellings referred from various clinical departments were included in this study on the basis of a predefined inclusion and exclusion criteria. All the soft tissue swellings were imaged by with high resolution USG transducer of 4-12 MHz with Seimens Acuson NX3 and Phillips Affinity -30. The sonographic indices of the soft tissue swellings noted were location/plane, nature, size, margin, echo pattern and calcification. Vascularity of the lesions was assessed with color and spectral Doppler parameters. The ultrasonographic diagnosis was then correlated initially on the clinical diagnosis. Soft tissue swellings like foreign bodies, liquefied abscess and hematomas were 19 readily confirmed to evaluate the accuracy of USG in these lesions. In patients who underwent surgical excision a correlation of USG and HPE was also done. For statistical purposes p value less than 0.05 was taken as statistically significant.

Results: Out of total 200 patients there were 92 males and 108 females with a M:F ratio of 1:1.17. The mean ageof the studied cases was found to be 33.31 +/- 16.44. Majority of the patients (55.5%) presented aspainless swelling while painful swelling and traumatic swelling was seen in 54 (27%) and 35 (17.5%) patients respectively. Common locations were upper limb (33%) followed by lower limb (27.5%).Majority of the lesion were subcutaneous (60.5%) followed by arising from deeper structures (13%). On ultrasound 113 (62.5%) patients had solid lesions whereas cystic and mixed echogenic lesions were seen in 61 (30.5%) and 24 (12%) patients. In majority of the cases the lesions had a well-defined margin (63%) whereas ill-defined and lobulated margins were seen in 67 (33.5%) and 5 (2.5%) patients respectively. Most lesions were either hypoechoic (41.5%) or anechoic (24%) and on Doppler majority of the lesions were avascular (73.5%). 82 (41%) patients had tumoral lesions whereas 108 (54%) were found to haven on tumoral lesions. 20 (10%) patients had foreign body as the cause of swelling and all of them were readily diagnosed on ultrasound. Most common site of lipoma was found to be tors (26/44) and majority of them were found in subcutaneous plane (77%). Lipoma, nerve sheath tumors and ganglion cysts were found to be hyperechoic (75%), hypoechoic (66.66%) and anechoic (75%) in majority of the cases.

Conclusion: High frequency ultrasound imaging is found to be capable of diagnosing musculoskeletal soft tissue pathologies with high accuracy. It has the distinct advantage of being dynamic, non-invasive, affordable, accurate, quick and accessible imaging modality for a variety of musculoskeletal soft tissue pathologies.

Keywords: soft tissue pathologies, high frequency ultrasound, Dynamic Imaging, Echogenicity.