Indirect soft-tissue and osseous signs on knee MRI of surgically proven meniscal tears.
OBJECTIVE
The purpose of this study was to determine the frequency of abnormal MR signal intensity in soft tissues and osseous structures in association with surgically proven meniscal tears.


METHODS
Seventy patients underwent 1.5-T MRI of the knee and arthroscopy within 3 months. MR images were reviewed by two radiologists for parameniscal cysts, bowing and edema around the collateral ligament, meniscal extrusion, cartilage loss, and nonlinear and linear subchondral marrow edema. The findings were correlated with the arthroscopic findings. The positive predictive value (PPV), sensitivity, and specificity of indirect signs were calculated.


RESULTS
Fifty-three medial and 28 lateral meniscal tears were found at arthroscopy. The PPV of indirect signs of meniscal tear was 0.17-1.00 for reader 1 and 0.37-1.00 for reader 2. The PPV of parameniscal cysts was 1.00 for medial and lateral meniscal tears for both readers. The specificity and PPV of periligamentous edema and cruciate ligament bowing for medial meniscal tear were 0.94 and 0.98 for both readers, 0.88 and 0.94 for reader 1, and 0.94 and 0.97 for reader 2. The specificity and PPV of subchondral marrow edema for medial meniscal tear were 0.88 and 0.96 for reader 1 and 0.94 and 0.97 for reader 2 and for lateral meniscal tear were 0.98 and 0.92 for reader 1 and 1.00 and 1.00 for reader 2. The specificity and PPV of linear subchondral marrow edema for medial meniscal tear were 0.94 and 0.97 for reader 1 and 1.00 and 1.00 for reader 2. For lateral meniscal tear, the values were 0.98 and 0.89 for reader 1 and 1.00 and 1.00 for reader 2. The specificity and PPV of nonlinear subchondral marrow edema for medial meniscal tear were 0.94 and 0.89 for reader 1 and 1.00 and 1.00 for reader 2. For lateral meniscal tear, the values were 0.89 and 0.97 for reader 1 and 1.00 and 1.00 for reader 2. The specificity and PPV of cartilage loss for medial meniscal tear were 0.88 and 0.94 for reader 1 and 0.88 and 0.93 for reader 2. For lateral meniscal tear, the values were 0.85 and 0.56 for reader 1 and 0.97 and 0.80 for reader 2.


CONCLUSIONS
Indirect MRI signs occur in association with meniscal tears and can aid diagnostic confidence when the MRI meniscal appearance is equivocal.
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19066, USA. dianebergin@yahoo.com
Diane
D
Bergin
Hilary
H
Hochberg
Adam C
AC
Zoga
Naila
N
Qazi
Laurence
L
Parker
William B
WB
Morrison
D000293:Adolescent; D000328:Adult; D003238:Connective Tissue / Q000473:pathology*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000473:pathology*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D000070600:Tibial Meniscus Injuries