Effect of multislice acquisition on T<sub>1</sub> and T<sub>2</sub> measurements of articular cartilage at 3T

Watanabe, Atsuya; Boesch, Chris; Obata, Takayuki; Anderson, Suzanne E.

doi:10.1002/jmri.20962

Cited by 33 publications

(32 citation statements)

References 36 publications

(67 reference statements)

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“…[5][6][7]9,[12][13][14][15] In particular, PG content decreases before the loss of denatured collagen, but morphologic changes are not seen in the early stage of osteoarthritis (OA). [4][5][6][7] Although the early denaturalization of articular cartilage can be depicted by T 1 r mapping as well as T 2 mapping and dGEM-RIC, [10][11][12][13][14][15][16] its depiction requires an elongated scanning time. Previous reports in the literature used 4 or 5 diŠerent T 1 r-prepared images with diŠerent TSLs for calculation, which required more than 12 min of scanning time.…”

Section: Discussionmentioning

confidence: 99%

“…2,10 The feasibility of T 1 r mapping in assessing the PG content of articular cartilage has been reported to be the same as that of sodium MR imaging and dGEMRIC. 1,[5][6][7][8][9][10][11][12][13][14][15][16][17] Correlation has been reported between changes in PG content and the T 1 r relaxation time in vitro, 6,9 and in vivo studies have shown the utility of T 1 r mapping for PG changes in articular cartilage, especially for patients with osteoarthritis. [5][6][7]9,12,[13][14][15] However, accurate assessment takes a relatively long time because it requires scan- ning of 4 or 5 diŠerent T 1 r-prepared images with diŠerent times of spin-lock pulse (TSLs), [5][6][7]9,[12][13][14][15] and performance of T 1 r mapping would be preferable with a shorter examination time.…”

Section: Introductionmentioning

confidence: 98%

“…1,2 As well, MR imaging can be used to assess the biochemical properties of articular cartilage by quantitative imaging approaches, such as sodium MR imaging, delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC), magnetization transfer imaging, T 2 mapping, diŠusion-weighted imaging, and T 1 r mapping. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] These approaches have been used to allow histological analysis of cellular morphology, proteoglycan (PG) concentrations, collagenˆber size, and orientation of hyaline cartilage. Sodium MR imaging and dGEMRIC have been employed to quantify the changes in PG depletion in articular cartilage.…”

Section: Introductionmentioning

confidence: 99%

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A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

et al. 2010

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Purpose: We assessed the clinical utility of our proposed simpliˆed method for T 1 r mapping calculations.Materials and Methods: Ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T 1 r-prepared images using 5 diŠerent time of spin-lock pulses (TSL＝1, 20, 40, 60, and 80 ms), produced conventional T 1 r maps (cT 1 r maps) using all TSLs, and recomputed our proposed simpliˆed T 1 r maps (sT 1 r maps) using a decreasing number of TSLs (from 4 to 2). We then investigated the diŠerences and correlations in T 1 r values of the tissues obtained using diŠerent numbers of spin-lock times.Results: There was a strong positive correlation (single measure intraclass correlation coe‹cient＝0.948; 95z conˆdence interval＝0.911 to 0.970) in T 1 r values of tissues between the cT 1 r and sT 1 r [1, 80] maps. The 2 maps were comparable, though there was a small diŠerence in T 1 r value between the two. The total scan time to acquire the data from 5 spin-lock times was 16 min 15 s. Similarity of the T 1 r [1, 80] map with the conventional approach reduced scan time by 60z, to 6 min 30 s.Conclusion: The clinical relevance of our proposed simpliˆed method is potentially similar to that of the conventional method, and our method requires a shorter examination time and generally preserves the reliability of the T 1 r relaxation time of the tissues.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

et al. 2010

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“…A central issue in the successful development of such therapeutics is the ability to monitor and potentially modify implant properties on an ongoing basis. The application of magnetic resonance imaging (MRI) for visualizing cartilage clinically has been well established, 1,2 while more recently, approaches have been developed to monitor cartilage matrix components in human subjects [3][4][5][6][7][8] and in engineered cartilage constructs. [9][10][11][12][13][14] These latter techniques may be particularly useful for tailoring therapeutic interventions after implantation into a defect.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive Assessment of Glycosaminoglycan Production in Injectable Tissue-Engineered Cartilage Constructs Using Magnetic Resonance Imaging

Ramaswamy

Uluer²,

Leen³

et al. 2008

Tissue Engineering Part C: Methods

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The glycosaminoglycan (GAG) content of engineered cartilage is a determinant of biochemical and mechanical quality. The ability to measure the degree to which GAG content is maintained or increases in an implant is therefore of importance in cartilage repair procedures. The gadolinium exclusion magnetic resonance imaging (MRI) method for estimating matrix fixed charge density (FCD) is ideally suited to this. One promising approach to cartilage repair is use of seeded injectable hydrogels. Accordingly, we assess the reliability of measuring GAG content in such a system ex vivo using MRI. Samples of the photopolymerizable hydrogel, poly(ethylene oxide) diacrylate, were seeded with bovine chondrocytes (*2.4 million cells/sample). The FCD of the constructs was determined using MRI after 9, 16, 29, 36, 43, and 50 days of incubation. Values were correlated with the results of biochemical determination of GAG from the same samples. FCD and GAG were found to be statistically significantly correlated (R 2 = 0.91, p < 0.01). We conclude that MRI-derived FCD measurements of FCD in injectable hydrogels reflect tissue GAG content and that this methodology therefore has potential for in vivo monitoring of such constructs.

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“…This is important for the feasibility of quantitative T2 relaxation time measurements in clinical practice. However, potential error sources are introduced by using a MSME spin echo sequence [10][11][12]. A multislice sequence requires sliceselective refocusing pulses.…”

mentioning

confidence: 99%

MR T2 Relaxation Time Measurements for Cartilage and Menisci

Baum

Link²,

Dardzinski³

2011

Cartilage Imaging

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IntroductionMagnetic Resonance Imaging (MRI) can be used not only for morphologic but also for quantitative assessment of knee cartilage. Quantitative T1rho and T2 relaxation time measurements and dGEMRIC (delayed Gadolinium enhanced MRI of the cartilage) have emerged as potential cartilage biomarkers to assess early degenerative disease. This chapter focuses on the T2-technique and clinical applications of hyaline cartilage and meniscal T2 relaxation time measurements in particular at the knee.The chapter is structured into four parts: After a brief background section, image acquisition and processing are outlined. Subsequently, image analysis and clinical applications are presented. BackgroundEarly stages of knee osteoarthritis (OA) are characterized by degradation of components of the extracellular matrix of the cartilage [1,2]. The proteoglycan content decreases and the collagen network shows signs of disorganization. The latter induces higher water mobility and consequentially increased water content within the cartilage. These initial cartilage changes are subclinical, i.e., individuals do not have symptoms of OA. T1rho and T2 relaxation times are affected by these pathophysiological processes [3,4]. Whereas T1rho relaxation time is more sensitive to the proteoglycan content of the cartilage, T2 relaxation time is more sensitive to cartilage hydration and orientation and integrity of the collagen network. Therefore, T1rho and T2 are noninvasive biomarkers for cartilage degeneration. These biomarkers may be used to detect early stages of the disease, quantitatively assess disease severity, sensitively monitor disease progression, and monitor OA therapy. Since they are sensitive to tissue components of cartilage that change before morphologic signs are detectable, they are particularly suited for the early disease stages, which are not accessible with standard morphological MR imaging [5]. In one of the early studies, Dardzinski et al. analyzed T2 measurements in asymptomatic volunteers and found a reproducible pattern of increasing T2 that was proportional to the known spatial variation in cartilage water [6]. Based on these findings, the authors postulated that these regional T2 differences were secondary to the restricted mobility of cartilage water within an anisotropic solid matrix. In a subsequent clinical study, Mosher et al. studied asymptomatic volunteers and individuals with symptoms of patellar chondromalacia using quantitative T2 maps of patellar cartilage and found an asymptomatic increase in T2 with aging as well as an increase in cartilage T2 from the radial zone to the articular surface [7]. Based on these studies and findings, investigators adopted T2 relaxation time measurements to assess cartilage degeneration in clinical studies, which culminated in implementing T2 relaxation time measurements in the NIH sponsored Osteoarthritis Initiative (OAI) multicenter trial. Image Acquisition and Processing Imaging Sequences and Field StrengthQuantitative T2 relaxation time measurements in vivo are t...

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

Cited by 33 publications

References 36 publications

A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

Noninvasive Assessment of Glycosaminoglycan Production in Injectable Tissue-Engineered Cartilage Constructs Using Magnetic Resonance Imaging

MR T2 Relaxation Time Measurements for Cartilage and Menisci

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

Cited by 33 publications

References 36 publications

A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

A Simplified Method of T1ρ Mapping in Clinical Assessment of Knee Joint

Noninvasive Assessment of Glycosaminoglycan Production in Injectable Tissue-Engineered Cartilage Constructs Using Magnetic Resonance Imaging

MR T2 Relaxation Time Measurements for Cartilage and Menisci

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Product

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