Prabhu Radhan Radhakrishnan, Biji Babu, Arumugam S, Prakash A, Praveenkumar V
BACKGROUND MRI is a highly accurate imaging modality for diagnosing meniscal tears. Pre-operatively, surgeons need information not only on the presence of the meniscal tears but also on their morphological characteristics, in order to decide the most appropriate surgical method. MR Axial images of the menisci have been observed to help in identification and characterization of the meniscal tear, though they are under-used. MATERIALS AND METHODS A prospective observational study of 73 menisci in 63 patients, with prior MRI examination and who underwent arthroscopic surgery of knee over a period of 2 years was conducted. Images were reviewed by an MSK radiologist for the identification of meniscal tears, who was blinded to the arthroscopic findings. The routine MRI sequences along with reconstructed axial images acquired from sagittal PDFS images were used for the evaluation. The images were analysed in 5 different groups which included Coronal, Sagittal, Coronal and Sagittal, Axial, and Axial and Sagittal. A 3-point scale was used to report the confidence level for the diagnosis of meniscal tear in each imaging group. The results were then statistically analysed using McNemar test to calculate the sensitivity, specificity and accuracy for detection and characterization of meniscal tears in the different imaging planes, considering the arthroscopic findings as the gold standard. RESULTS The specificity, sensitivity, and accuracy in the characterization of meniscal tears were increased with the inclusion of reconstructed axial images in combination with other imaging modalities. This imaging plane did not need added image acquisition time, but the interpretation of the tear morphology was little difficult due to poor image quality and needed regular practice. The axial plane was extremely helpful in the correct diagnosis of radial tears and root tears. We saw no statistically significant difference between the imaging groups of medial and lateral menisci in the diagnosis of tears (p>0.05). CONCLUSION The detection and characterization of meniscal tear morphology is more accurate using the reconstructed axial imaging plane, alongside the sagittal and coronal planes.
