Comparative accuracy of magnetic resonance imaging and ultrasonography in confirming clinically diagnosed patellar tendinopathy.
BACKGROUND
Diagnosis of patellar tendinopathy is based primarily on clinical examination; however, it is commonplace to image the patellar tendon for diagnosis confirmation, with the imaging modalities of choice being magnetic resonance imaging (MRI) and ultrasonography (US). The comparative accuracy of these modalities has not been established.


OBJECTIVE
Magnetic resonance imaging and US have good (>80%) accuracy and show substantial agreement in confirming clinically diagnosed patellar tendinopathy.


METHODS
Cohort study (diagnosis); Level of evidence, 2.


METHODS
Magnetic resonance imaging and US (gray scale [GS-US] and color Doppler [CD-US]) features of 30 participants with clinically diagnosed patellar tendinopathy and 33 activity-matched, asymptomatic participants were prospectively compared. Accuracy, sensitivity, specificity, positive and negative predictive values, and the likelihood of positive and negative test results were determined for each technique.


RESULTS
The accuracy of MRI, GS-US, and CD-US was 70%, 83%, and 83%, respectively (P = .04; MRI vs GS-US). The likelihood of positive MRI, GS-US, and CD-US was 3.1, 4.8, and 11.6, respectively. The MRI and GS-US had equivalent specificity (82% vs 82%; P = 1.00); however, the sensitivity of GS-US was greater than MRI (87% vs 57%; P = .01). Sensitivity (70% vs 87%; P = .06) and specificity (94% vs 82%; P = .10) did not differ between CD-US and GS-US.


CONCLUSIONS
Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. GS-US and CD-US may represent the best combination for confirming clinically diagnosed patellar tendinopathy because GS-US had the greatest sensitivity, while a positive CD-US test result indicated a strong likelihood an individual was symptomatic.
Warden
Stuart J
SJ
Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, Indiana 46202, USA. stwarden@iupui.edu
Kiss
Zoltan S
ZS
Malara
Frank A
FA
Ooi
Alistair B T
AB
Cook
Jill L
JL
Crossley
Kay M
KM
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017847:Patellar Ligament / Q000503:physiopathology*; D052256:Tendinopathy / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D014739:Victoria