n %n %n n n %n Medial meniscus Negative Positive 3 8 27.3% 12.7% 11 14.9% 72.7% 8 55 87.3% 63 85.1% Total 11 63 74 100.0% 100.0% 100.0% %n n n %n n %n 72.7% 8 55 63 87.3% 85.1% Lateral meniscus Negative Positive 27.3% 100.0% 3 8 12.7% 11 14.9% Total 11 63 74 100.0% 100.0% © Pol J Radiol, 2011; 76(1): 30-40 Aydin H et al – Is the quantitative diffusion-weighted MR Imaging… Table 8A,B. Concordance of DWI+ADC mapping (with three b-factors) with regard to MR imaging findings. No significant statistical differences between sequences for the evaluation of any meniscal tears (p>0.05). A MRG- Negative DWI + ADC map Positive Total Sensitivity=%87 Specificity=%27 PPV=0.87 NPV=0.27 Fisher's test P=0.352 60 (n50 ) s ien40 t t a fp30 o re20 b um10 N 0 B MRG- Negative DWI + ADC map Positive Total Sensitivity=%73 Specificity=%13 PPV=0.13 NPV=0.73 Fisher's test P=0.352 60 (n50 ) s ien40 t t a fp30 o re20 b um10 N 0 Med. men. neagtive Med. men. positive Lat. men. neagtive Lat. men. positive Unmatch MRI-DWI+ADC map Match Unmatch MRI-DWI+ADC map Match quality of images and measurements [12,13]. Single-shot EPI, SE or GE is a standard technique that can provide us with a complete image within a second; it is robust to motion and has high resistance to magnetic field inhomoge- neities leading to image distortion [12]. Spatial resolution in this technique tends to be used to obtain high-speed imag- ing and a high signal-to-noise ratio [12,13]. DWI sensitivity to diffusion (characterised by its b-value) can be adjusted by altering the combination of gradient pulse amplitude; the higher the b-factor, the more sensitive is the image to the effects of diffusion [12]. Besides motion, DWI can still be affected by MR properties other than that of diffusion, e.g. T2 weighting. To remove the effects different than dif- fusion, ADC map is used. It is created by combining two images – with and without DWI – or by using two b-values (in order to create an ADC map free of all contrast influ- ences other than the displacement of water during the application of the diffusion gradients) [12,13]. ADC map- ping with b-values from 0 to 1000 s/mm2 can be performed and it has been shown to be more sensitive than DWI, as it is influenced only by the magnitude of the diffused water molecules [12]. In the early days, DWI and ADC mapping provided very useful information about the stroke and tumours of the brain and were used especially within the central nervous system. However, recently, they have also been applied in head and neck tumours, to diagnose breast cancer, illustrate the extension of prostate and rectal carci- nomas, response of the tumours to radiotherapy or chemo- therapy and even for the whole-body studies [12]. Here, in this report, for the first time in the literature, the efficacy of DWI and ADC mapping with different b-factors was ana- lysed in the diagnosis of meniscal tears. As mentioned above; DWI and ADC mapping with b-value of 400 s/mm2 do have higher sensitivity and 100% specific- ity in visualising meniscal tears. ADC map with b-factor of 50 s/mm2 has the least importance in the diagnosis of all meniscal tears, due to the lowest sensitivity connect- ed with its less spatial resolution. DWI results, especial- ly in the diagnosis of the lateral meniscal tears, reveal a very low specificity and a higher NPV. The detectability of meniscal tears with DWI is better for the medial menis- cus than for the lateral site. ADC map with b-factor of 400 sec/mm2 is more successful to reveal the medial meniscal tears, while the ADC map with b-value of 800 s/mm2 is better suited for revealing the lateral meniscal tears than other imaging modalities. However, in the identification of lateral meniscal tears, ADC mapping with either of the b-factors shows lower specificity, with higher NPV and lower PPV. DWI combined with ADC mapping with three b-values shows a sensitivity of over 70% for lateral tears and of over 85% for medial meniscal tears. Both combined sequnces, seem to be less relevant, especially in visualisa- tion of lateral meniscal tears, due to their low specificity and higher NPV. Considering all above items, we should report that DWI and ADC mapping can easily be applied in daily prac- tice, especially in diagnosing medial meniscus tears but the application of both imaging modalities with different 39