Delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) in early knee osteoarthritis

Abstract

Delayed contrast-enhanced MRI of cartilage (dGEMRIC) is a noninvasive technique to study cartilage glycosaminoglycan (GAG) content in vivo. This study evaluates dGEMRIC in patients with preradiographic degenerative cartilage changes. Seventeen knees in 15 patients (age 35-70) with arthroscopically verified cartilage changes (softening and fibrillations) in the medial or lateral femoral compartment, knee pain, and normal weight-bearing radiography were included. MRI (1.5 T) was performed precontrast and at 1.5 and 3 hr after an intravenous injection of Gd-DTPA 2؊ at 0.3 mmol/kg body weight. T 1 measurements were made in regions of interest in medial and lateral femoral cartilage using sets of five turbo inversion recovery images. Precontrast, R 1 (R 1 ‫؍‬ 1/T 1 , 1/s) was slightly lower in diseased compared to reference compartment, indicating increased hydration (P ‫؍‬ 0.01). Postcontrast, R 1 was higher in diseased than in reference compartment at 1.5 hr, 3.45 ؎ 0.90 and 2.64 ؎ 0.58 (mean ؎ SD), respectively (P < 0.01), as well as at 3 hr, 2.94 ؎ 0.60 and 2.50 ؎ 0.37, respectively (P ‫؍‬ 0.01). The washout of the contrast medium was faster in diseased cartilage as shown by a higher R 1 at 1.5 than at 3 hr in the diseased but not in the reference compartment. In conclusion, dGEMRIC can identify GAG loss in early stage cartilage disease with a higher sensitivity at 1.5 than 3 hr. Magn Reson Med 49: 488 -492, 2003.

Effect of multislice acquisition on T1 and T2 measurements of articular cartilage at 3T

“…To observe the whole cartilage of the patella, medial condyle, or lateral condyle at a time, at least this degree of slice number and interslice gap are required. An ETL ϭ 7, which is comparable with values used for clinical studies (12,27), was used in this study. Theoretically, it is possible to reduce the MT effect by reducing the number of ETL; however, acquisition time will increase inversely proportional to the number of ETL.…”

“…There are several kinds of pulse sequences for T 1 or T 2 measurements. Fast-spin-echo inversion-recovery (FSE-IR) sequence and multi-spinecho (MSE) sequence have been commonly used for T 1 measurement and T 2 measurement of articular cartilage, respectively (7,9,(12)(13)(14)(15). The main reason to use these sequences for clinical evaluation is that they offer acceptable calculation accuracy and reproducibility in a suitable acquisition time.…”

“…Transverse relaxation time (T 2 ) mapping is an MRI technique that can evaluate the integrity of the collagen network structure and water content in cartilage (8,9). These two MRI techniques have had their capacities validated in basic studies (6,8,10,11) and have been used for clinical evaluations (12)(13)(14)(15). The dGEMRIC technique requires longitudinal relaxation time (T 1 ) measurement, whereas T 2 mapping requires T 2 measurement; both techniques employ dedicated pulse sequences.…”

Probing articular cartilage damage and disease by quantitative magnetic resonance imaging

“…Nonetheless, T 1,Gd has been correlated with proteoglycan content [27,79,99]. T 1,Gd also varies depending on the region of cartilage [31,49] and is higher in load-bearing cartilage compared with non-contact regions [100]. Some studies have used dGEMRIC to compute GAG content in healthy cartilage [31] and cartilage with preradiographic damage [49].…”

Quantitative MRI of cartilage and bone: degenerative changes in osteoarthritis

“…These include correspondence of the dGEMRIC index to cartilage 'softening' as seen by arthroscopy (199), correlation of the dGEMRIC index with the level of physical activity (200), improved differentiation of disease relative to radiography in individuals with hip dysplasia (201), discriminatory power of dGEMRIC in radiographically similar compartments of the knee (202), sensitivity of medial/lateral dGEMRIC to malalignment in the knee (202), lower dGEMRIC values in individuals with ACL injury (203) and sensitivity to changes in knee cartilage following posterior cruciate ligament (PCL) injury (204).…”