Posterior tibialis tendon tears: comparison of the diagnostic efficacy of magnetic resonance imaging and ultrasonography for the detection of surgically created longitudinal tears in cadavers.
OBJECTIVE
The optimal advanced imaging method for detection and characterization of posterior tibialis tendon (PTT) tears is unclear. The purpose of this study was to investigate the utility of ultrasonography (US) and MR imaging in the detection of surgically created PTT tears in cadavers.


METHODS
This was a prospective blinded study in which 16 fresh cadaveric foot and ankle specimens (3 men, 13 women; average age at death 83.9 years; age range 71-96 years) were scanned with both US and MR imaging before and after the surgical creation of 64 variable length longitudinal tears of the PTT. Ultrasonography was performed with a 12 MHz linear transducer with independent interpretations of static and dynamic studies separately by two blinded and experienced musculoskeletal radiologists. MR imaging was performed at 1.5 T with a standard transmit-receive extremity coil using axial, sagittal, coronal T1-weighted (TR 600, TE 20), and axial fast spin echo proton density and T2-weighted (TR 3000, TE 161/20, ETL 12) images. MR images were reviewed independently by two experienced musculoskeletal radiologists who were blinded to the status of the PTT.


RESULTS
Sensitivity, specificity, and accuracy of MR imaging in the diagnosis of PTT tears were 73%, 69%, and 72%, respectively. Dynamic US interpretation yielded values of 69% sensitivity, 81% specificity, and 72% accuracy. Static US interpretation was less reliable than dynamic interpretation, and the only significance of static imaging was a high specificity (94%) for detection of longitudinal tears. The positive predictive value (PPV) for MR imaging and US was 88% and 92% respectively, and the negative predictive value (NPV) was 46% for both MR imaging and US.


CONCLUSIONS
Our results suggest that US and MR imaging perform at the same level for the detection of surgically created longitudinal PTT tears in a cadaveric model. US has a higher specificity compared with MR imaging.
Gerling
Michael C
MC
Department of Orthopedics, University of California San Diego/UCSD San Diego, USA.
Pfirrmann
Christian W A
CW
Farooki
Shella
S
Kim
Choll
C
Boyd
Gordon J
GJ
Aronoff
Michael D
MD
Feng
Sunah A K
SA
Jacobson
Jon A
JA
Resnick
Donald
D
Brage
Michael E
ME
D000368:Aged; D000369:Aged, 80 and over; D016512:Ankle Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D002102:Cadaver; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D037081:Posterior Tibial Tendon Dysfunction / Q000175:diagnosis; D012680:Sensitivity and Specificity; D013708:Tendon Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D013710:Tendons / Q000000981:diagnostic imaging* / Q000601:surgery; D014463:Ultrasonography