Fig. 2.

Shoulder imaging of a 26 year-old female 4 days following COVID vaccine injection. (A) Axial PDFS demonstrates edema in the deltoid muscle with extension to the approximate location of the quadrilateral space (Yellow Arrows); there is also adenopathy in the axillary region (Red Arrows). (B) Sagittal PDFS demonstrates edema in the region of the quadrilateral space, which surrounds the long head of the triceps (Yellow Arrows); there are small adjacent lymph nodes (Red Arrows). (C) Coronal T2FS demonstrates prominence draining vessels and/or lymphatics extending from the deltoid inflammation (Yellow Arrows) to the inflamed region of the quadrilateral space (Red Arrow). (D) Coronal T1 images demonstrate an unusual increased T1 signal in the vessels/lymphatics extending to the approximate region of the quadrilateral space (Yellow Arrows). Color version of figure is available online.