See page 1002 for the question.
Morel-Lavallee lesion of the lateral right thigh was sustained after a cycling accident.
The MR hip arthrography (figure 4) showed a mildly hypertrophied acetabular labrum with a focal partial thickness articular-sided anterosuperior tear.
Oblique sagittal T1W fat saturation MR image showing the focal partial thickness anterosuperior labral tear (arrow).
Lateral to the right hip joint, an encapsulated and septated high T2W signal intensity fluid collection was demonstrated, deep to the subcutaneous fat layer and superficial to the iliotibial band aponeurosis, measuring 8.8 × 6 × 2.3 cm (craniocaudal × anteroposterior × transverse) in dimensions (figures 5 and 6). A 14-mm low T2W signal intensity focus at the superior region of this fusiform fluid collection (arrow, figure 7) was compatible with blood products.
The MR hip arthrography study's coronal T1W fat saturation MR image shows the fusiform Morel-Lavallee lesion fluid collection (thin arrow) with homogeneous hypointense signal in-between the subdermal fat layer and the iliotibial band aponeurosis. The intralesional hyperintense foci abutting its lateral aspect represent subacute blood products (thick arrow). No definite hypointense capsule is seen.
Coronal T2W fat saturation images from the MR hip arthrography demonstrating myriad internal septations (arrow) and the presence of an incomplete hypointense capsule (dashed arrow), with variable thickness, around the T2W hyperintense Morel-Lavallee fluid collection.
Coronal T2W fat saturation images at a more posterior location demonstrating the hypointense …