#4 is correct - Iliotibial band tendonosis without bursitis
This is most likely a thickened ipsilateral iliotibial band.
NOTES: The imager again should do long axis (LAX) and short axis (views) of the both sides for comparison. Color or Power Doppler over the affected area would have been useful. What is interesting about this case is that there is a lack of bursitis that is commonly associated with iliotibial band inflammation. It is much easier to measure if the images are zoomed so that area of interest is primarily in focus..
"X" denote axial measurement of the ipsilateral (RT) to contralateral (LT) Iliotibial band (IT). Note the increase in axial size of the IT in ipsilateral to contralateral comparison
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