Time-saving opportunities in knee osteoarthritis: T 2 mapping and structural imaging of the knee using a single 5-min MRI scan

To assess the discriminative power of a 5-min quantitative double-echo steady-state (qDESS) sequence for simultaneous T measurements of cartilage and meniscus, and structural knee osteoarthritis (OA) assessment, in a clinical OA population, using radiographic knee OA as reference standard. Fifty-three subjects were included and divided over three groups based on radiographic and clinical knee OA: 20 subjects with no OA (Kellgren-Lawrence grade (KLG) 0), 18 with mild OA (KLG2), and 15 with moderate OA (KLG3). All patients underwent a 5-min qDESS scan. We measured T relaxation times in four cartilage and four meniscus regions of interest (ROIs) and performed structural OA evaluation with the MRI Osteoarthritis Knee Score (MOAKS) using qDESS with multiplanar reformatting. Between-group differences in T values and MOAKS were calculated using ANOVA. Correlations of the reference standard (i.e., radiographic knee OA) with T and MOAKS were assessed with correlation analyses for ordinal variables. In cartilage, mean T values were 36.1 ± SD 4.3, 40.6 ± 5.9, and 47.1 ± 4.3 ms for no, mild, and moderate OA, respectively (p