Original Article A Negative Positive DWI findings Total Sensitivity=%87 Specificity=%27 PPV=0.87 NPV=0.27 Fisher's test P=0.352 A D 60 (n50 ) s ien40 t t a fp30 o re20 b um10 N 0 Med. men. neagtive Med. men. positive B E C F Table 4A,B. DWI results for both menisci. No significant statistical differences in comparison to routine MRI findings – the diagnosis of meniscal tears (p>0.05). %n n n %n n %n Medial meniscus Negative Positive 27.3% 3 8 12.7% 11 14.9% 8 72.7% 55 87.3% 63 85.1% Total 11 63 74 100.0% 100.0% 100.0% B Negative Positive DWI findings Total Sensitivity=%73 Specificity=%13 PPV=0.13 NPV=0.73 Fisher's test P=0.352 n %n %n n n %n A C 60 (n50 ) s ien40 t t a fp30 o re20 b um10 N 0 Lat. men. neagtive Lat. men. positive © Pol J Radiol, 2011; 76(1): 30-40 Lateral meniscus Negative Positive 72.7% 27.3% 100.0% 3 8 12.7% 11 14.9% Total 11 63 74 100.0% 100.0% 8 55 63 87.3% 85.1% DWI B D Negative DWI Positive Negative Positive Figure 3. Sagittal T2W images (A and B) and coronal PDW image showing medial meniscal tear, especially in posterior horn. DWI (D), ADC map with b-factor of 400 (E) and 800 (F) showed the tear clearly. body positions and 50–90% of body weight is transmitted through the menisci in extension or flexion [2,3]. They dis- tribute the stress forces over a large area of articular car- tilage and over the underlying bone, enhance the ability of articular cartilage to provide a nearly frictionless articula- tion that can perform extensive biomechanical maneuvers which minimise the stress effect on the joint [3,9]. Meniscal tears can therefore disable the load-bearing function of meniscus, increase stress on tibial and femoral articular cartilages, ultimately leading to degeneration and sponta- neous osteonecrosis [3,9,10].Treatment of meniscal tears depends on the configuration, size and location of the tear. It includes non-meniscal surgery, meniscal repair, partial 36 Figure 4. Lateral meniscal tear. Coronal PDW image (A) presenting the tear, especially in the medial parts of the lateral meniscus. There was also a fluid collection surrounding the lateral meniscus (B). Coronal DWI (C) and Coronal ADC mapping (b=800) scans also showed the tear in the lateral meniscus clearly. meniscectomy and complete meniscectomy. Oblique- horizontal and longitudinal tears are usually amenable to repair, whereas radial and complex tears usually require partial or complete meniscectomy [6,9,10]. As mentioned above, MR imaging is the most sensitive, non-invasive technique for the diagnosis of meniscal tears