Quantitative and qualitative analysis of knee magnetic resonance imaging using low- and high-field strength units

The aim of this study was to determine the subjective and objective evaluation of image quality between an MRI unit with 0.3T and an MRI unit with 1.5T METHODS: An experimental study was performed on 25 healthy volunteers. Imaging was performed with an Esaote O-Scan Light 0.3T and a GE Optima 450 W 1.5T MRI units. PD FSE imaging was performed in the sagittal, transverse and coronal planes. The acquired images were evaluated using subjective and objective image analysis. Subjective image analysis was performed using ViewDEX 3.2 software, in which three radiologists evaluated the images. Objective image analysis was performed using ImageJ software, which was used to measure SNR and CNR. IMB SPSS 26.0 software was used to determine whether the data were normally distributed (Shapiro-Wilk test), and then a paired-samples T-test or dependent Wilcoxon signed rank test was performed.

The results of objective image quality analysis (SNR and CNR) showed statistically significant differences in measurements of the medial meniscus in the coronal plane and articular cartilage in the transverse plane (p < 0.001). No statistically significant differences were found in the measurements of the distal femur in the sagittal plane. The results of the subjective image analysis showed significant differences in favor of the 1.5T MRI device for all observed criteria (ACL (p = 0.026), PCL (p = 0.003), lateral and medial menisci (p = 0.004), articular cartilage (p = 0.001), and overall image quality (p = 0.011)).

As expected, the MRI unit with a higher magnetic field strength (1.5T) achieved better results than the unit with the lower magnetic field strength (0.3T). However, it must be mentioned that the subjective measurement values were between 2.7 and 4.0, indicating good to perfect visualization of the selected anatomy.