MR Imaging in Meniscal Injury of Knee Joint : ROC Analysis of Diagnositic Performance According to Imaging Planes and Window Widths

Magnetic resonance(MR) is the most widely used diagnostic tool for the meniscal tears. 160 images of menisci of 30 patients and 10 normal subjects were photographed with coronal and sagittal planes and with narrow and conventional wide window settings. To access the diagnostic efficacy of imaging planes and the window settings, MR images of two window settings with coronal and sagittal planes of menisci were interpreted by four experienced observers. Images were graded on a five-point scale to enable receiver operating characteristic (ROC) curve analysis. The ROC curves constructed from the coronal plane were similar to those of the sagittal images. The area of under ROC curve constructed from the narrow window setting was inferior to one from the wide window settings. There was no difference of diagnostic performance between four observer to detect meniscal abnormality. This suggests that there is no globally significant improvement in the detection of meniscal tear when narrow window setting are used for interpretation, and there is probable improvement when both coronal and sagittal images are used for meniscal MRI.