OBJECTIVE. The purpose of this study was to determine the appropriate
minimum waiting time between an impingement test with subacromial inje
ction and subsequent MR imaging to avoid misinterpretation if the inje
cted fluid is still present. CONCLUSION. MR imaging should be delayed
a minimum of 24 kr after a subacromial injection. Fluid in the subacro
mial space 24 hr after subacromial injection is unrelated to an imping
ement test.