MRI grading system for abnormal meniscal signal intensity

MRI grading system for abnormal high meniscal signal intensity was reported by Lotysch et al.  MR grades 1, 2, and 3 have been used:

• grade 1: small focal area of hyperintensity, no extension to the articular surface
• grade 2: linear areas of hyperintensity, no extension to the articular surface
  • 2a: linear abnormal hyperintensity with no extension to the articular surface
  • 2b: abnormal hyperintensity reaches the articular surface on a single image
  • 2c: globular wedge-shaped abnormal hyperintensity  with no extension to the articular surface

Grade 2 meniscal signal was found to be associated with a meniscal tear on arthroscopy. Therefore, grade 2 was further subdivided into 2a, 2b, and 2c. Dillon et al. found that 50% of patients with grade 2c had meniscal tears on arthroscopy.

• grade 3: abnormal hyperintensity extends to at least one articular surface (superior or inferior), and is referred as a definite meniscal tear