Is the quantitative Diffusion-Weighted MR Imaging and ADC mapping with b-values of 50, 400, and 800 sec/mm(2) a reliable method for evaluation of meniscal tears in the knee?
BACKGROUND
Our aim was to evaluate the efficacy of Diffusion-Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) mapping with different b-factors in visualisation of meniscal tears.


METHODS
Seventy-four patients; 30 males and 44 females, 37 left and 37 right knees with meniscal tears were involved in this study. Eleven of them were lateral meniscal tears and 63 - medial meniscal tears. DWI was obtained by 3D-SE Echo-planar Imaging (EPI) in coronal and sagittal planes. ADC mapping was carried out in coronal planes with b-factors of 50, 400, and 800 sec/mm(2). The statistical analysis of DWI and ADC mapping results was performed with the use of the Fisher's test and the chi-square test.


RESULTS
1. For both menisci and 74 tears: DWI revealed 86% sensitivity and 100% specificity (p=0.149) with a positive predictive value (PPV) of 1 and a negative predictive value (NPV) of 0.09. ADC mapping with b-value of 400 sec/mm(2) had 78% sensitivity, and 100% specificity, with PPV of 1 and NPV of 0.06 (p=0.230). 2. For the lateral meniscal tears: DWI and ADC mapping with b-value of 800, for the medial meniscal tears: DWI and ADC mapping with b-factor of 400 s/mm(2) revealed higher sensitivity and specificity than other methods.


CONCLUSIONS
Quantitative DWI and ADC mapping, especially with b-factor of 400 sec/mm(2), may be an alternative to routine MR imaging sequences for the visualisation of meniscal tears in the knee.
Departmant of Radiology, Dışkapı Yıldırım Beyazıt Eğitim Ve Araştırma Hastanesi, Ankara, Turkey.
Hasan
H
Aydin
Volkan
V
Kizilgöz
Baki
B
Hekimoğlu