T2 relaxation time measurements in osteoarthritis

David-Vaudey, Eve; Ghosh, Srinka; Ries, Michael D.; Majumdar, Sharmila

doi:10.1016/j.mri.2004.01.071

Cited by 208 publications

(184 citation statements)

References 34 publications

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“…These reports led to the conclusion that cartilage T 2 is primarily a measure of collagen integrity and is relatively insensitive to loss of PG. David-Vaudey et al (13) reported that T 2 was elevated in various clinical grades of human cartilage obtained from knee replacement surgery patients, as indicated by images acquired at 1.5T. They also correlated the T 2 MRI data with orthopedic and histological grades and polarized microscopy, and reported higher T 2 values in grade 1 compared to grades 0 and 2 due to increased water content (swelling) during early stages of OA.…”

Section: Discussionmentioning

confidence: 96%

“…Several researchers have measured T 2 relaxation times in a variety of cartilage specimens, such as pig femoral condyles (9), shoulder joints of beagles (10), bovine patellae (11,12), and human cartilage (13)(14)(15). Nieminen et al (11) and Mlynarik et al (14) showed that the variation of T 2 relaxation times in normal and matrix-depleted cartilage confirmed that T 2 of articular cartilage is sensitive to the integrity of collagen in the ECM.…”

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confidence: 99%

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T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

Regatte

Akella

Lonner

et al. 2006

Magnetic Resonance Imaging

303

299

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Purpose:To quantify the spin-lattice relaxation time in the rotating frame (T 1 ) in various clinical grades of human osteoarthritis (OA) cartilage specimens obtained from total knee replacement surgery, and to correlate the T 1 with OA disease progression and compare it with the transverse relaxation time (T 2 ). Materials and Methods:Human cartilage specimens were obtained from consenting patients (N ϭ 8) who underwent total replacement of the knee joint at the Pennsylvania Hospital, Philadelphia, PA, USA. T 2 -and T 1 -weighted images were obtained on a 4.0 Tesla whole-body GE Signa scanner (GEMS, Milwaukee, WI, USA). A 7-cm diameter transmit/receive quadrature birdcage coil tuned to 170 MHz was employed.Results: All of the surgical knee replacement OA cartilage specimens showed elevated relaxation times (T 2 and T 1 ) compared to healthy cartilage tissue. In various grades of OA specimens, the T 1 relaxation times varied from 62 Ϯ 5 msec to 100 Ϯ 8 msec (mean Ϯ SEM) depending on the degree of cartilage degeneration. However, T 2 relaxation times varied only from 32 Ϯ 2 msec to 45 Ϯ 4 msec (mean Ϯ SEM) on the same cartilage specimens. The increase in T 2 and T 1 in various clinical grades of OA specimens were ϳ5-50% and 30 -120%, respectively, compared to healthy specimens. The degenerative status of the cartilage specimens was also confirmed by histological evaluation. Conclusion:Preliminary results from a limited number of knee specimens (N ϭ 8) suggest that T 1 relaxation mapping is a sensitive noninvasive marker for quantitatively predicting and monitoring the status of macromolecules in early OA. Furthermore, T 1 has a higher dynamic range (Ͼ100%) for detecting early pathology compared to T 2 . This higher dynamic range can be exploited to measure even small macromolecular changes with greater accuracy compared to T 2 . Because of these advantages, T 1 relaxation mapping may be useful for evaluating early OA therapy.

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Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

Regatte

Akella

Lonner

et al. 2006

Magnetic Resonance Imaging

303

299

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“…Prominent in these are: proton-based methods such as T 2 relaxation mapping (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), delayed gadoliniumenhanced magnetic resonance imaging contrast (dGEM-RIC) (21,22), T 1r relaxation mapping (23)(24)(25)(26) and the direct MRI of sodium (27)(28)(29)(30). T 2 is predominantly affected by changes in collagen content and to a smaller extent in PG in the tissue.…”

Section: Osteoarthritismentioning

confidence: 99%

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage

et al. 2006

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In this article, both sodium magnetic resonance (MR) and T 1r relaxation mapping aimed at measuring molecular changes in cartilage for the diagnostic imaging of osteoarthritis are reviewed. First, an introduction to structure of cartilage, its degeneration in osteoarthritis (OA) and an outline of diagnostic imaging methods in quantifying molecular changes and early diagnostic aspects of cartilage degeneration are described. The sodium MRI section begins with a brief overview of the theory of sodium NMR of biological tissues and is followed by a section on multiple quantum filters that can be used to quantify both bi-exponential relaxation and residual quadrupolar interaction. Specifically, (i) the rationale behind the use of sodium MRI in quantifying proteoglycan (PG) changes, (ii) validation studies using biochemical assays, (iii) studies on human OA specimens, (iv) results on animal models and (v) clinical imaging protocols are reviewed. Results demonstrating the feasibility of quantifying PG in OA patients and comparison with that in healthy subjects are also presented. The section concludes with the discussion of advantages and potential issues with sodium MRI and the impact of new technological advancements (e.g. ultra-high field scanners and parallel imaging methods). In the theory section on T 1r , a brief description of (i) principles of measuring T 1r relaxation, (ii) pulse sequences for computing T 1r relaxation maps, (iii) issues regarding radio frequency power deposition, (iv) mechanisms that contribute to T 1r in biological tissues and (v) effects of exchange and dipolar interaction on T 1r dispersion are discussed. Correlation of T 1r relaxation rate with macromolecular content and biomechanical properties in cartilage specimens subjected to trypsin and cytokineinduced glycosaminoglycan depletion and validation against biochemical assay and histopathology are presented. Experimental T 1r data from osteoarthritic specimens, animal models, healthy human subjects and as well from osteoarthritic patients are provided. The current status of T 1r relaxation mapping of cartilage and future directions is also discussed. Copyright # 2006 John Wiley & Sons, Ltd. KEYWORDS: cartilage; arthritis; spin-lock; T1rho; sodium; MRI OSTEOARTHRITIS Osteoarthritis (OA) affects more than half of the population above the age of 65 (1,2) and has a significant negative impact on the quality of life of elderly individuals (3). The economic costs in the USA from OA have been estimated to be more than 1% of the gross domestic product (4). OA is now increasingly viewed as a metabolically active joint disorder of diverse etiologies. The biochemistry of the disease is characterized by the following changes in cartilage: reduced proteoglycan (PG) concentration, possible changes in the size of collagen fibril and aggregation of PG, increased water content and increased rate of synthesis and degradation of matrix macromolecules. The earliest changes in the cartilage due to OA result in a partial breakdown in the proteoglyc...

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“…The present study used a fast spin echo (FSE) pulse sequence for image acquisition and T 2 calculations (16) while previous investigators have commonly used a spin echo (SE) pulse sequence (22,45,46). The reduced scanning time afforded by an FSE versus an SE sequence is a clear benefit for scanning in a clinical setting, but the FSE sequence has potential for the formation stimulated echos.…”

Section: Discussionmentioning

confidence: 99%

Bias of cartilage T2 values related to method of calculation

Koff¹,

Amrami²,

Felmlee³

et al. 2008

Magnetic Resonance Imaging

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Purpose-To determine how different methods for calculating T 2 affect the resulting T 2 values of patellar cartilage.Materials and Methods-T 2 -weighted images of patellar cartilage for 10 subjects were acquired using 2 MRI scanners. T 2 values of patellar cartilage were calculated using linear, weighted and nonlinear fitting algorithms for a mono-exponential decay equation. T 2 values were also calculated for the superficial, middle and deep zones of the cartilage Results-All three methods of calculation resulted in significantly different T 2 values (p<0.0001). The weighted calculation produced the highest T 2 values and the non-linear calculation produced the lowest T 2 values. The average difference of T 2 value between the methods was under 5 ms. Similar results were found in a zonal analysis of the tissue. The non-linear calculation of T 2 consistently had the best fit to the acquired data. Conclusion-The T 2 value of patellar cartilage depends on the method of calculation. It is unclear if larger T 2 value differences would be seen in subjects diagnosed with osteoarthritis. This study highlights the potential difficulty of comparing different studies to one another based on the method of T 2 calculation.

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T2 relaxation time measurements in osteoarthritis

Cited by 208 publications

References 34 publications

T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage

Bias of cartilage T2 values related to method of calculation

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T2 relaxation time measurements in osteoarthritis

Cited by 208 publications

References 34 publications

T1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T1ρ with T2

T1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T1ρ with T2

Sodium and T1ρ MRI for molecular and diagnostic imaging of articular cartilage

Bias of cartilage T2 values related to method of calculation

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Product

Resources

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T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

T_1ρ relaxation mapping in human osteoarthritis (OA) cartilage: Comparison of T_1ρ with T₂

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage