Lateral down-sloping of the acromion: a useful MR sign?
OBJECTIVE
The anterior acromion may appear to slope downward in a lateral direction on coronal-oblique magnetic resonance (MR) images of the shoulder. We sought to determine the significance of this finding as a marker of rotator cuff impingement.


METHODS
MR studies of 58 subjects (26 with impingement, 32 with glenohumeral instability) were retrospectively analysed. Subjective down-sloping of the acromion was compared to standardized acromial measurements made on MR (acromial axis, width of the anterior acromion, and distance of the acromioclavicular joint from the superior glenoid) and clinical diagnosis.


RESULTS
Interobserver variance for lateral down-sloping was fair (kappa = 0.5). One reader's assessment of lateral down-sloping of the acromion correlated with standardized MR measurements. Subjective lateral down-sloping of the acromion did not, however, correlate with impingement.


CONCLUSIONS
The subjective finding of a laterally down-sloping acromion on coronal-oblique MR images, while partially validated by standardized measurements, is not predictive of impingement syndrome.
Yao
L
L
UCLA Department of Radiological Sciences 90024, USA.
Lee
H Y
HY
Gentili
A
A
Shapiro
M M
MM
D000174:Acromion / Q000473:pathology*; D000328:Adult; D000367:Age Factors; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D012737:Sex Factors; D019534:Shoulder Impingement Syndrome / Q000175:diagnosis*; D012785:Shoulder Joint / Q000473:pathology