UTE bi-component analysis of T2* relaxation in articular cartilage

Shao, Hongda; Chang, Eric Y.; Pauli, Chantal; Zanganeh, Soorena Azam; Bae, Won C.; Chung, Christine B.; Tang, Guangyu; Du, Jiang

doi:10.1016/j.joca.2015.08.017

Cited by 54 publications

(70 citation statements)

References 35 publications

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“…However, we measured T1rho at 0° both at the beginning and end of the scan, and found changes less than 5%. Third, patellar cartilage may show a multi-component behavior (13,29,30), but only a single component analysis was performed. Multi-component analysis has a high signal-to-noise ratio demand and may require longer scan time (31), which is difficult with this protocol, which is already 10 hours long.…”

Section: Discussionmentioning

confidence: 99%

Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage

Shao

Pauli

et al. 2017

Osteoarthritis and Cartilage

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PURPOSE To investigate the effect of sample orientation on T1rho and T2 values of articular cartilage in histologically confirmed normal and abnormal regions using a whole-body 3T scanner, providing information on the angular dependence of T1rho and T2 in clinical imaging. MATERIALS AND METHODS Eight human cadaveric patellae were evaluated using a 2D CPMG sequence for T2 measurement as well as a 2D spin-locking prepared spiral sequence and a 3D magnetization-prepared angle-modulated partitioned-k-space spoiled gradient echo snapshots (3D MAPSS) sequence for T1rho measurement. Each sample was imaged at six angles from 0° to 100° relative to the B0 field. T2 and T1rho values were measured for three regions (medial, apex and lateral) with three layers (10% superficial, 60% middle, 30% deep). Multiple histopathologically confirmed normal and abnormal regions were also used to evaluate the angular dependence of T2 and T1rho relaxation in articular cartilage. RESULTS Our study demonstrated a strong magic angle effect for T1rho and T2 relaxation in articular cartilage, especially in the deeper layers of cartilage. On average over eight patellae, T2 values were increased by 231.8% (72.2% for superficial, 237.6% for middle, and 187.9% for deep layers) while T1rho values were increased by 92% (31.7% for superficial, 69% for middle, and 140% for deep layers) near the magic angle. Both normal and abnormal cartilage showed similar T1rho and T2 magic angle effect. CONCLUSIONS Changes in T1rho and T2 values due to the magic angle effect can be several times more than that caused by degeneration, and this may significantly complicate the clinical application of T1rho and T2 as an early surrogate marker for degeneration.

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Section: Discussionmentioning

confidence: 99%

Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage

Shao

Pauli

et al. 2017

Osteoarthritis and Cartilage

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“…However, changes in T2 and T2* are nonspecific and can be caused by multiple factors including hydration, macromolecular content, and tissue anisotropy with comparable changes occurring in disparate settings [5][6][7][8][9] . Bi-component T2 and T2* mapping techniques have been used to improve the specificity of T2 analysis by assessing the individual water components of musculoskeletal tissues [10][11][12][13][14][15][16][17][18][19][20][21][22] . Bi-component T2 and T2* mapping methods have measured two distinct T2 components in cartilage assumed to represent short relaxing water bound to the macromolecular matrix and long relaxing bulk water [12][13][14]21,22 .…”

Section: Introductionmentioning

confidence: 99%

“…Bi-component T2 and T2* mapping techniques have been used to improve the specificity of T2 analysis by assessing the individual water components of musculoskeletal tissues [10][11][12][13][14][15][16][17][18][19][20][21][22] . Bi-component T2 and T2* mapping methods have measured two distinct T2 components in cartilage assumed to represent short relaxing water bound to the macromolecular matrix and long relaxing bulk water [12][13][14]21,22 . Bi-component T2* mapping methods have been used in cortical bone to differentiate between water bound to the organic matrix and free water in the Haversian systems [15][16][17] , Bi-component T2 and T2* mapping methods have also been used in the meniscus to differentiate between macromolecular bound water and bulk water [18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Assessment of different fitting methods for in-vivo bi-component T2* analysis of human patellar tendon in magnetic resonance imaging

Liu

Kijowski

2017

MLTJ

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SummaryPurpose: To investigate the robustness of four fitting methods for bi-component effective spin-spin T2 (T2*) relaxation time analysis of human patellar tendon. Methods: A three-dimensional (3D) cone ultrashort echo-time (UTE) sequence was performed on the knees of ten healthy volunteers at 3.0T. Four fitting methods incorporating either Gaussian or Rician noise distribution were used for voxel-by-voxel bi-component T2* analysis of the patellar tendon. The T2* for the short relaxing (T**,s) and long relaxing (T*2,l) water components and the fraction of the short relaxing water component (fs) were measured, and different fitting methods were compared using Friedman's and Wilcoxon signed rank tests. A numerical simulation study was also performed to predict the accuracy and precision of bi-component T2* parameter estimation in tendon at different signal-tonoise ratios (SNR) levels. Results: The average T*2,s , T*2,l, fs of human patellar tendon were 1.5ms, 30ms, and 80% respectively. Incorporating different noise models and fitting methods influenced the measured bi-component T2* parameters. Fitting methods incorporating Rician noise were superior to traditional fitting methods for bi-component T2* analysis especially at lower SNR. fs and T*2,s were less sensitive than T*2,1 to noise at even moderate and low SNR. The result of the in-vivo bi-component T2* analysis of tendon agreed well with numerical simulations. Conclusion: Our study demonstrated the use of a 3D cone UTE sequence to perform in vivo voxelby-voxel bi-component T2* analysis of human patellar tendon. Incorporating Rician noise was useful for improving bi-component T2* analysis especially at lower SNR. Level of evidence: IV.

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“…With the improvement of clinical MRI technology, resolving cartilage thickness in 2-4 or more pixels becomes possible for quantitative human MRI (39). Consequently, these pixels of equal size could be used to represent different depths of cartilage (40,41). This type of depth-dependent regional analysis is superior to the bulk analysis, since a regional analysis separates the different characteristics between surface and deep cartilage.…”

Section: Discussionmentioning

confidence: 99%

Image interpolation improves the zonal analysis of cartilage T2 relaxation in MRI

Badar

Xia

2017

Quant. Imaging Med. Surg.

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Background: This project aimed to investigate the improvement in the detection of osteoarthritis (OA) in cartilage by the interpolation of T2 images, in the situation when the native MRI resolution is insufficient to resolve the depth-dependent T2 characteristics in articular cartilage (AC).Methods: Eighteen intact canine knee joints that were healthy or had mild (contralateral) or severe OA were T2-imaged in a 7T/20 cm MRI system at 200 µm/pixel resolution (macro-MRI). Two image analysis methods were used to interpolate the images to 100 µm/pixel, i.e., by Fourier-transforming the time-domain FID (Free Induction Decay) signal using the Varian NMR software and by interpolating the 2D T2 image using the ImageJ software. and the interpolated 100 µm resolutions were subdivided into two equal-thickness regions and three-equal thickness regions based on clinical MRI protocols. A new method divided the T2 profiles into three-unequal thickness zones according to the T2 profiles at 17.6 µm/pixel from the same cartilage imaged in a 7 Tesla/9 cm µMRI system. Both interpolation methods improved the depth-dependent T2 images/profiles in macro-MRI. The unequal zone division in T2 had better OA sensitivity than the equal zone division. The threeequal zone division of T2 profiles had better OA sensitivity than the two-equal zone division. The statistical significant difference between the healthy and mild OA cartilage is detected (P=0.0018) only by the unequal zone division method at 100 µm resolution.Conclusions: Data interpolation improves the T2 sensitivity in MRI of cartilage OA. Unequal division of tissue thickness enables better early stage of OA detection than the equal division.

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UTE bi-component analysis of T2* relaxation in articular cartilage

Cited by 54 publications

References 35 publications

Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage

Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage

Assessment of different fitting methods for in-vivo bi-component T2* analysis of human patellar tendon in magnetic resonance imaging

Image interpolation improves the zonal analysis of cartilage T2 relaxation in MRI

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