O R I G I N A L A R T I C L E Is the quantitative Diffusion-Weighted MR Imaging and ADC mapping with b-values of 50, 400, and 800 sec/mm2 a reliable method for evaluation of meniscal tears in the knee? Hasan Aydin, Volkan Kizilgöz, Baki Hekimoğlu Departmant of Radiology, Dışkapı Yıldırım Beyazıt Eğitim Ve Araştırma Hastanesi, Ankara, Turkey Author’s address: Hasan Aydın, Departmant of Radiology, Dışkapı Yıldırım Beyazıt Eğitim Ve Araştırma Hastanesi, Dışkapı Eğ. Araşt. Hast. İrfan Baştuğ Caddesi Altındağ/Ankara-Turkey Postal Code: 06110, e-mail: dr.hasanaydin@hotmail.com Signature: © Pol J Radiol, 2011; 76(1): 30-40 Received: 2010.04.19 Accepted: 2011.01.10 Background: Material/Methods: Results: Conclusions: Summary 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. 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/mm2. The statistical analysis of DWI and ADC mapping results was performed with the use of the Fisher’s test and the chi-square test. 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/mm2 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/mm2 revealed higher sensitivity and specificity than other methods. Quantitative DWI and ADC mapping, especially with b-factor of 400 sec/mm2, may be an alternative to routine MR imaging sequences for the visualisation of meniscal tears in the knee. Key words: DWI • ADC mapping • b-factors • medial meniscus tears • lateral meniscus tears PDF file: http://www.polradiol.com/fulltxt.php?ICID=881407 Background MR imaging shows high accuracy in the identification of internal pathologies of the knee, especially the meniscal tears and injuries [1,2]. MR imaging provides important information about bone and soft tissue disorders in and around the knee joint [3,4]. It can help avoiding unneces- sary diagnostic arthroscopy and show the size, location and characteristics of meniscal tears that will guide treat- ment [2–5]. Coupled with a patient’s history and physical exam findings, MR imaging has a high utility in direct- ing the treatment of individuals with knee pain [2,4–6]. In most of the radiology departments, T1 and PD-T2W SE, 30 FSE, Gradient Echo (GE) sequences of transverse, sagittal and coronal images with or without Fat-Saturation (FS) are still used as a routine knee MR protocol [4,5]. The accu- racy for meniscal tears and other knee pathologies evalu- ated by 3D-MR imaging was shown to be more than 90% in several papers [1,2,4,5]. With the advancement of the technology, newer MRI sequences have been introduced to improve the quality of a routine MR imaging protocol and and have been applied to increase the sensitivity and speci- ficity for the diagnosis of meniscal injuries [2,4,7]. Such a new sequence, that is the DWI and ADC mapping, will be analysed in this study. We will also try to provide informa- tion about the utility of 3D-DWI and ADC mapping with