Original Article A B Figure 5. Medial meniscal tear. Coronal PDW image (A) and coronal ADC mapping with b-value of 400 sec/mm2 (B). in the knee. High-quality knee MRI can be performed on high- or low-field systems with a local knee coil [2–5]. Images are acquired in transverse, coronal and sagittal planes, with a field of view of about 16 cm, 3–4 mm slice thickness, imaging matrix of about 192*256, an adequate signal-to-noise ratio and an appropriate receiver band- width [3–5]. Several authors reported that 3D-MR imaging with a stan- Table 7A,B. Results of ADC mapping with different b-values for medial and lateral meniscal tears. © Pol J Radiol, 2011; 76(1): 30-40 D B 20 43 63 86.0% 85.1% Lateral meniscus Negative Positive 83.3% 16.7% 100.0% 4 7 14.0% 11 14.9% Total 24 50 74 100.0% 100.0% Figure 6. Coronal PDW image (A) and sagittal T2W image (B) of the lateral meniscal tear, especially in the posterior horn (yellow arrows). ADC mapping with b-value of 400 (C) and 800 (D) in the coronal plane, showing the lateral meniscal tear. ADC map with b=800 also visualised the tear in the medial menisci, as shown in PDW imaging (green arrows). A C 45 )n40 ( ts35 ien30 a25 t fo20 p re15 m10 b u N 5 0 B Negative Positive b=800 Total Sensitivity=%64 Specificity=%32 PPV=0.14 NPV=0.83 Fisher's test P=0.740 n %n %n n n %n Lat. men. neagtive Lat. men. positive %n n n %n n %n Medial meniscus Negative Positive 16.7% 4 7 14.0% 11 14.9% 20 83.3% 43 86.0% 63 85.1% Total 100.0% 100.0% 24 50 74 100.0% Med. men. neagtive Med. men. positive A Negative Positive b=800 Total Sensitivity=%79 Specificity=%64 PPV=0.88 NPV=0.24 Fisher's test P=0.263 38 45 )n40 ( ts35 ien30 a25 t fo20 p re15 m10 b u N 5 0 Negative b=800 Positive Negative b=800 Positive dard protocol had 86–96% sensitivity and 84–94% speci- ficity for diagnosing the medial meniscal tears, 68–86% sensitivity and 92–98% specificity for the lateral meniscal tears [4–6,11]. With great advances in MR systems, technol- ogy and RF coils, new sequences appear both in the stud- ies and in a daily practice [3–5]. 3D-DWI and ADC mapping with b-factors are so new that they are used nowadays in examinations of the whole body [12]. DWI provides image contrast by measuring the diffusion properties of water within tissues, either unidirectional (isotropic) or multidi- rectional (anisotropic) [12,13]. The majority of DWI studies performed clinically to date has focused on the measure- ment of extra-cellular water diffusion – both the magnitude and direction of diffusion – in order to show free diffusion of water protons [13]. DWI-ADC mapping can be adversely affected by artifacts from motion rather than from the dif- fusion of molecules. Even vascular pulsations, voluntary movements and respiration can easily interfere with the