Quadrilateral space region inflammation and other incidental findings on shoulder MRI following recent COVID-19 vaccination: Three case reports

We present 3 cases reporting the normal appearance of the post COVID-19 vaccination on shoulder MRI exams. All 3 patients were imaged 1 to 5 days post-vaccination for unrelated MSK shoulder symptoms, and none reported any symptoms besides mild shoulder discomfort for a day or 2 following vaccine administration. All 3 patients demonstrated characteristic deltoid edema, quadrilateral space region edema and axillary nodal prominence. Vessel prominence with t2 and t1 increased signal draining to the approximate location of the quadrilateral space and axilla was an associated feature. The normal appearance of the covid-19 vaccine on shoulder MRI has not been previously described, and recognition by the radiologist will prevent erroneous differential diagnosis, unnecessary medical workups, and detract from the clinically relevant pathological imaging findings in patients with shoulder pain.