Original Article Table 2. DWI findings obtained during visualisation of all meniscal tears. n %n %n n n %n 1 0 1 9.1% 0.0% 1.4% MRI findings Negative Positive Total 100.0% 11 63 74 10 90.9% 63 73 100.0% 100.0% 98.6% 100.0% DWI findings Negative Positive Total Sensitivity=%86 Specificity=%100 PPV=1 NPV=0.09 Fisher's test P=0.149 DWI negative DWI positive 70 (n60 ) s tn50 e i ta40 p fo30 r eb20 m u10 N 0 Negative MRI Positive PPV of 1 and NPV of 0.09 (Table 2, Figure 1). DWI results were not significantly statistically different from routine MRI find- ings for visualisation of meniscal tears (p>0.05). ADC map- ping with b-value of 50 sec/mm2 has 38% sensitivity, and 100% specificity, with PPV of 1 and NPV of 0.02 (p=1.00) (Table 3A). ADC mapping with b-value of 400 sec/mm2 has 78% sensitivity and 100% specificity, with PPV of 1 and NPV of 0.06 (p=0.230) (Table 3B, Figure 2), and ADC mapping with b-value of 800 sec/mm2 has 68% sensitivity and 100% spec- ificity, with PPV of 1 and NPV of 0.04 (p=0.230) (Table 3C, Figure 2), correlated with MR imaging results. ADC mapping with all b-factors revealed no significant statistical differenc- es when compared to routine MRI in visualisation of menis- cal tears (p>0.05). DWI and ADC mapping with b-factor of 400 sec/mm2 have higher sensitivity and specificity than other imaging modalities, with 100% PPV and less than 10% NPV. For 63 medial meniscal tears: DWI revealed 87% sensi- tivity and 27% specificity (p=0.352) with PPV of 0.87 and NPV of 0.27 (Table 4A, Figure 3). For 11 lateral menis- cal tears: DWI has 73% sensitivity and 13% specific- ity (p=0.352) with PPV of 0.13 and NPV of 0.73 (Table 4B, Figure 4). There were no significant statistical differ- ences between DWI results for both menisci and routine MRI findings, for the diagnosis of meniscal tears (p>0.05). However, DWI had a very low specificity and a high NPV, especially for the lateral meniscal tears. A C © Pol J Radiol, 2011; 76(1): 30-40 B D Figure 1. Medial meniscal tear. Coronal PDW (A) showing a medial meniscal tear. In the sagittal T2W image (B) the tear was found in posterior horn mostly. In this patient, coronal ADC mapping (with b-value of 800 sec/mm2) (C) also showed the tear but DWI image (d) depicted the tear more clearly, when compared to ADC map (b=800). (p=0.738), with PPV of 0.82 and NPV of 0.13 (Table 5A). For 11 lateral meniscal tears, its sensitivity is 45% and specificity 63% (p=0.738), with PPV of 0.18 and NPV of 0.87 (Table 5B). The results of ADC mapping with b-value of 50 sec/mm2 for both menisci reveal no significant statistical differences as compared to the findings of the routine MRI in the evalu- ation of meniscal tears (p>0.05). Moreover, ADC mapping had a lower sensitivity and specificity for the evaluation of medial meniscal tears but (especially for the visualisation of lateral meniscal tears) it showed some difficulties due to its low PPV and high NPV when compared to the routine MRI. In contrast to routine MRI findings, ADC mapping with b-factor of 400 sec/mm2 used for 63 medial meniscal tears has 79% sensitivity and 64% specificity (p=0.263), with PPV of 0.88 and NPV of 0.24 (Table 6A, Figures 2, 3, 5). For 11 lateral meniscal tears, it has 64% sensitivity and 21% speci- ficity (p=0.263), with PPV of 0.12 and NPV of 0.76 (Table 6B, Figure 6). ADC mapping with b-value of 400 sec/mm2 for medial and lateral menisci tears revealed no significant sta- tistical differences as compared to the routine MRI (p>0.05); it had higher sensitivity, specificity and PPV, especially for diagnosing medial meniscal tears but had lower specificity and high NPV for the identification of lateral meniscal tear. ADC mapping with b-factor of 800 sec/mm2 for the medi- al meniscal tears has 68% sensitivity and 36% specific- ity (p=0.740), with PPV of 0.86 and NPV of 0.17 (Table 7A, Figures 1–3). In the evaluation of lateral meniscal tears, it has 64% sensitivity and 32% specificity (p=0.740) with PPV of 0.14 and NPV of 0.83 (Table 7B, Figure 4). ADC mapping with b-value of 800 sec/mm2 for medial and lateral menisci tears has no significant statistical differences in compari- son to the routine MRI (p>0.05); it has higher sensitivity in visualisation of both meniscal tears than ADC mapping with other b-factors. However, it reveals lower specificity and a high NPV, especially for lateral meniscal tears (like the other ADC map sequences). ADC mapping with b-value of 50 sec/mm2 for 63 medial meniscal tears reveals 37% sensitivity and 45% specificity When we study the concordance of DWI and ADC map- ping (with three b-factors) and compare their results with 34