Estimation of T2* Values in Healthy and Pathologic Achilles Tendon: Mono and Bi Exponential Analysis

Tbini, Zeineb; Mars, Mokhtar; Chelli, Mouna

doi:10.1109/ssd.2018.8570675

Cited by 2 publications

(4 citation statements)

References 5 publications

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“…Meanwhile, biological tissues have demonstrated distinct water compartments (or pools) using T2, T2*, and, more recently, T1ρ relaxation times [19][20][21][22]. Multiple studies have shown that tendons have two distinct water components: bound water and free water [22][23][24][25][26][27][28]. Free water is located between the network of collagen bundles, and bound water is closely associated with collagen and/or peptidoglycan [22,27].…”

Section: Introductionmentioning

confidence: 99%

“…Free water is located between the network of collagen bundles, and bound water is closely associated with collagen and/or peptidoglycan [22,27]. Several studies have shown that the short or fast relaxation component correlates with tendon pathology and clinical scores [22,24,27,28]. Single exponential models are incapable of differentiating between short and long relaxation components.…”

Section: Introductionmentioning

confidence: 99%

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Bi-Exponential 3D UTE-T1ρ Relaxation Mapping of Ex Vivo Human Knee Patellar Tendon at 3T

Malhi,

Moazamian,

Shin

et al. 2024

Bioengineering

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Introduction: The objective of this study was to assess the bi-exponential relaxation times and fractions of the short and long components of the human patellar tendon ex vivo using three-dimensional ultrashort echo time T1ρ (3D UTE-T1ρ) imaging. Materials and Methods: Five cadaveric human knee specimens were scanned using a 3D UTE-T1ρ imaging sequence on a 3T MR scanner. A series of 3D UTE-T1ρ images were acquired and fitted using single-component and bi-component models. Single-component exponential fitting was performed to measure the UTE-T1ρ value of the patellar tendon. Bi-component analysis was performed to measure the short and long UTE-T1ρ values and fractions. Results: The single-component analysis showed a mean single-component UTE-T1ρ value of 8.4 ± 1.7 ms for the five knee patellar tendon samples. Improved fitting was achieved with bi-component analysis, which showed a mean short UTE-T1ρ value of 5.5 ± 0.8 ms with a fraction of 77.6 ± 4.8%, and a mean long UTE-T1ρ value of 27.4 ± 3.8 ms with a fraction of 22.4 ± 4.8%. Conclusion: The 3D UTE-T1ρ sequence can detect the single- and bi-exponential decay in the patellar tendon. Bi-component fitting was superior to single-component fitting.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bi-Exponential 3D UTE-T1ρ Relaxation Mapping of Ex Vivo Human Knee Patellar Tendon at 3T

Malhi,

Moazamian,

Shin

et al. 2024

Bioengineering

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“…Estimated T * 2 values reflect structural properties and biochemical changes of the tissue. [9][10][11][12][13][14] For instance, short T * 2 values of bi-exponential model reflect changes in water content and collagen orientation in Achilles tendinopathy. 14 In addition to more frequently reported short and long relaxation components, oscillatory signals have also been reported by various studies; these oscillations have not been accounted for in bi-component fitting of multi-echo UTE-MRI data.…”

Section: Introductionmentioning

confidence: 99%

“…Bi‐exponential modelling has been widely studied in this regard to quantify the rapidly relaxing component (short) attributed to collagen water and more slowly relaxing component (long) attributed to interstitial water. Estimated

T_{2}^{*}

values reflect structural properties and biochemical changes of the tissue 9‐14 . For instance, short

T_{2}^{*}

values of bi‐exponential model reflect changes in water content and collagen orientation in Achilles tendinopathy 14 …”

Section: Introductionmentioning

confidence: 99%

Multi‐component relaxation modelling in human Achilles tendon: Quantifying chemical shift information in ultra‐short echo time imaging

Anjum

Gonzalez

Swain

et al. 2021

Magnetic Resonance in Med

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To examine multi-component relaxation modelling for quantification of on-and off-resonance relaxation signals in multi-echo ultra-short echo time (UTE) data of human Achilles tendon (AT) and compare bias and dispersion errors of model parameters to that of the bi-component model. Theory and Methods: Multi-component modelling is demonstrated for quantitative multi-echo UTE analysis of AT and supported using a novel method for determining number of MR-visible off-resonance components, UTE data from six healthy volunteers, and analysis of proton NMR measurements from ex vivo bovine AT. Cramer-Rao lower bound expressions are presented for multi-and bi-component models and parameter estimate variances are compared. Bias error in bi-component estimates is characterized numerically. Results: Two off-resonance components were consistently detected in all six volunteers and in bovine AT data. Multi-component model exhibited superior quality of fit, with a marginal increase in estimate variance, when compared to the bi-component model. Bi-component estimates exhibited notable bias particularly in R * 2,1 in the presence of off-resonance components. Conclusion: Multi-component modelling more reliably quantifies tendon matrix water components while also providing quantitation of additional non-water matrix constituents. Further work is needed to interpret the origin of the observed offresonance signals with preliminary assignments made to chemical groups in lipids and proteoglycans.

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Estimation of T2* Values in Healthy and Pathologic Achilles Tendon: Mono and Bi Exponential Analysis

Cited by 2 publications

References 5 publications

Bi-Exponential 3D UTE-T1ρ Relaxation Mapping of Ex Vivo Human Knee Patellar Tendon at 3T

Bi-Exponential 3D UTE-T1ρ Relaxation Mapping of Ex Vivo Human Knee Patellar Tendon at 3T

Multi‐component relaxation modelling in human Achilles tendon: Quantifying chemical shift information in ultra‐short echo time imaging

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