Diagnostic performance of susceptibility-weighted magnetic resonance imaging for the assessment of sub-coracoacromial spurs causing subacromial impingement syndrome.
OBJECTIVE
To evaluate the potential of susceptibility-weighted-magnetic-resonance-imaging (SWMR) for the detection of sub-coracoacromial spurs in patients with clinically suspected subacromial impingement syndrome (SAIS), compared to standard MR-sequences and radiographs.


METHODS
Forty-four patients with suspected SAIS were included. All patients underwent radiography, standard MRI of the shoulder and SWMR. Radiograph-based identification of sub-coracoacromial spurs served as goldstandard. Radiographs identified twenty-three spurs in twenty-three patients. Twenty-one patients without spur formation served as reference group. Detection rate, sensitivity/specificity and interobserver-agreements were calculated. Linear regression was applied to determine the relationship between size measurements on radiographs and MRI.


RESULTS
Detection rates for spurs on standard MRI and SWMR were 47.8 % and 91.3 % compared to radiography (p<0.001). SWMR demonstrated a sensitivity of 97.7 % (CI=0.92-1) and a specificity of 91.3 % (CI=0.788-1) for the identification of spurs. Standard MR-sequences achieved a sensitivity of 47.8 % (CI=0.185-0.775) and a specificity of 80.8 % (CI=0.642-0.978). Size measurements between SWMR and radiography showed a good correlation (R2=0.75;p<0.0001), while overestimating lesion size (5.7±1.2 mm; 4.3±1.3 mm;p<0.0001). Interobserver-agreement for spurs was high on SWMR (R2=0.74;p<0.0001), but low on standard MRI (R2=0.24;p<0.0001).


CONCLUSIONS
SWMR allows a reliable detection of sub-coracoacromial spur formation in patients with SAIS and is superior to standard MR-sequences using radiography as goldstandard.


CONCLUSIONS
• SWMR has the potential to reliably identify sub-coracoacromial spurs without radiation exposure. • SWMR provides comparable detection rates to conventional radiography for sub-coracoacromial spur formation. • SWMR yields higher detection rates compared to standard-MR regarding sub-coracoacromial spur formation. • SWMR can be implemented in routine shoulder MRI protocols.
Department of Clinical Radiology, Munich University Hospitals Campus Großhadern, Munich, Germany.
Dominik
D
Nörenberg
Department of Clinical Radiology, Munich University Hospitals Campus Großhadern, Munich, Germany.
Marco
M
Armbruster
Department of Radiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Yi-Na
YN
Bender
Department of Radiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Thula
T
Walter
Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich, Germany.
Hans U
HU
Ebersberger
Department of Radiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Gerd
G
Diederichs
Department of Radiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
Bernd
B
Hamm
Department of Trauma and Orthopedic Surgery, Shoulder and Elbow Service, Munich University Hospitals Campus Großhadern, Munich, Germany.
Ben
B
Ockert
Department of Radiology, Charité - University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany. marcus.makowski@charite.de.|Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK. marcus.makowski@charite.de.
Marcus R
MR
Makowski
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019534:Shoulder Impingement Syndrome / Q000000981:diagnostic imaging*; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000473:pathology
Acromioclavicular joint; Magnetic resonance imaging; Sub-coracoacromial spur;; Subacromial impingement; Susceptibility-weighted MR imaging