Comparison of high-field (1.5 T) and low-field (0.2 T) MR imaging for the reliability of meniscal diagnosis

The aim of this study was to evaluate the reliability of a low field strength MRI unit (0.2 T; Esaote, Biomedica) and a high field strength MRI unit (1.5 T; Siemens) in detecting meniscal lesions. Twenty patients were investigated on a 0.2-T low-field MRI unit and a 1.5-T high-field MRI unit for meniscal lesions. Evaluation was performed of four meniscal compartments (anterior and posterior medial and lateral meniscus), for a total of 80 observations. The reliability of diagnosis was ranked qualitatively on a three-point scale. Investigations of the high-field MRI unit revealed a meniscal tear in 6 patients and ruled out a tear in 14 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 58 observations and with moderate confidence in 22 observations. Investigations of the low-field MRI unit revealed a meniscal tear in 5 patients and ruled out tears in 15 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 39 observations, with moderate confidence in 38 observations, and with low confidence in 3 observations. The diagnosis in high-and low-field images was identical in 98.7 % of cases; in one patient observations from the high-field unit changed the therapeutic management. Diagnostic reliability was significantly higher with highfield strength MR imaging. Low field strength MR imaging shows comparatively high diagnostic accuracy for meniscal lesions compared to high field strength imaging; however, we demonstrated a significantly higher confidence in diagnosis with high-field MR imaging.