T2 Versus T2* MRI Mapping in the Knee Articular Cartilage at 1.5 Tesla and 3 Tesla

Abstract

Background: Recently, several studies have shown that T2 and T2* MRI parametric mapping are sensitive to structural and biochemical changes in the extracellular cartilage matrix. The objective of this study was to assess, compare and correlate quantitative T2 and T2* relaxation time of the knee articular cartilage at 1.5 Tesla (T) and 3 Tesla. Methods: Thirty-eight symptomatic patients with knee articular cartilage disease and forty-one asymptomatic volunteers were prospectively included in the study. Knee MRI examination was performed by 3 T and 1.5 T scanner. Multi-Echo Spin-Echo (MESE) and Multi-Echo Gradient Echo (MEGE) sequences were used to determine T2* and T2 maps. T2 and T2* relaxation times values were measured in three Regions Of Itnterest (ROI) on knee articular cartilage using mono-exponential analysis fitting algorithm. Results: There was a significant difference between volunteers and patients for T2 and T2* relaxation times values at 1.5 T and 3 T (p<0.05). The comparison between magnetic fields has shown lower T2 and T2* relaxation times at 3 T compared to 1.5 T. Pearson’s correlation analysis between T2 and T2* at 1.5T revealed a significant positive correlation for volunteers (r=0.245, p = 0.01) and a significant negative correlation for patients (0.016, p = 0.018). At 3T, there was a significant positive correlation between T2 and T2* for volunteers (r=0.076) and patients (r=0.165). The correlation of T2 and T2* between 1.5 T and 3T showed a significant negative correlation (r=-0.087, p = 0.01). Conclusion: T2* mapping may be used for the diagnosis of knee articular cartilage osteoarthritis with the advantage of relatively short scanning time, higher SNR, shorter echo times and the non-effect of the stimulated echo compared to T2 mapping.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

“…The number of studies per population was described as total studies (number of studies reporting T 2 data & number of studies reporting T 2 * data): A total of 31 (22 T 2 & 13 T 2 * ) studies were included in the myocardial infarction (MI) population [26,, 11 (11 T 2 & 0 T 2 * ) in heart transplantation [27,[69][70][71][72][73][74][75][76][77][78] [188] ( Table 1). The absolute T 2 and T 2 * values are dependent on field strength [189,190], therefore the average mapping values were noted separately for 1.5 T and 3 T, and it was also used as covariate in the meta-regression analysis. T 2 and T 2 mapping obtained in control subjects were recorded as values from healthy subjects, unless the control population was explicitly defined otherwise in the "population" column of Table 1.…”

Updates on Compositional MRI Mapping of the Cartilage: Emerging Techniques and Applications

“…T * 2 studies have shown good reproducibility. 6,14,15 T * 2 mapping offers unique information useful for the characterization of cartilage. T * 2 contrast captures shorter decay times in the cartilage and is less sensitive to bulk water.…”

Imaging of Cartilage and Chondral Defects: An Overview

“…T2* mapping appears to be more sensitive in the detection of these changes than T2, with values that vary much later in the disease process. The variation in the relaxation times have, however, been found to be higher for T2 as compared to T2* in a study by Mars et al [ 21 ]. The results are better for MRI at higher strengths (3T) as compared to MRI at lower strengths (1.5T).…”

“…While T2 mapping is SE-based, T2* is GRE-based and is thus more susceptible to magnetic field inhomogeneities. However, T2* uses shorter echo times (TE) and thus enables reduced scan times with higher resolution [ 18 , 19 , 20 , 21 ].…”