Clinical significance of intramuscular cysts in the rotator cuff and their relationship to full- and partial-thickness rotator cuff tears.

Objective: Secondary signs have been sought to help in the MR diagnosis of rotator cuff tears, especially partial-thickness tears. We sought to determine whether intramuscular cysts are always present with rotator cuff tears and the types of rotator cuff tears with which they present, and to establish the clinical significance of finding intramuscular cysts.

Materials And Methods: Retrospective analysis of our institution's database of 5,101 MRI examinations of the shoulder during an 8-year period resulted in 187 examinations in 185 patients who were thought to have intramuscular cysts.