Bias of cartilage T2 values related to method of calculation

Koff, Matthew F.; Amrami, Kimberly K.; Felmlee, Joel P.; Kaufman, Kenton R.

doi:10.1016/j.mri.2008.03.002

Cited by 34 publications

(35 citation statements)

References 41 publications

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“…Therefore, the sensitivity of T2 mapping to detect pathology in cartilage tissue may be improved by using an adequate fitting method [25]. Koff et al [26] found that linear, weighted and non-linear fitting algorithms resulted in significantly different T2 values (p < 0.0001). The non-linear calculation demonstrated the lowest T2 values, the linear calculation resulted intermediate T2 values and the weighted calculation resulted in the highest T2 values [26].…”

Section: Discussionmentioning

confidence: 99%

MRI T2 Mapping of Knee Articular Cartilage Using Different Acquisition Sequences and Calculation Methods at 1.5 Tesla

Mars¹,

Chelli²,

Tbini³

et al. 2018

Med Princ Pract

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Objective: This study aims to determine how magnetic resonance imaging (MRI) acquisition techniques and calculation methods affect T2 values of knee cartilage at 1.5 tesla and to identify sequences that can be used for high-resolution T2 mapping in short scanning times. Materials and Methods: This study was performed on phantom and 29 patients who underwent MRI of the knee joint at 1.5 tesla. The protocol includes T2 mapping sequences based on Single-Echo Spin Echo (SESE), Multi-Echo Spin Echo (MESE), Fast Spin Echo (FSE) and Turbo Gradient Spin Echo (TGSE). The T2 relaxation times were quantified and evaluated using three calculation methods (MapIt, Syngo Offline and mono-exponential fit). signal-to-noise ratios (SNR) were measured in all sequences. All statistical analyses were performed using the t-test. Results: The average T2 values in phantom were 41.7 ± 13.8 ms for SESE, 43.2 ± 14.4 ms for MESE, 42.4 ± 14.1 ms for FSE and 44 ± 14.5 ms for TGSE. In the patient study, the mean differences were 6.5 ± 8.2 ms, 7.8 ± 7.6 ms and 8.4 ± 14.2 ms for MESE, FSE and TGSE compared to SESE, respectively; these statistical results were not significantly different (p > 0.05). The comparison between the three calculation methods showed no significant difference (p > 0.05). The t-test showed no significant difference between SNR values for all sequences. Conclusion: T2 values depend not only on the sequence type but also on the calculation method. None of the sequences revealed significant differences compared to the SESE reference sequence. TGSE with its short scanning time can be used for high-resolution T2 mapping.

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Section: Discussionmentioning

confidence: 99%

MRI T2 Mapping of Knee Articular Cartilage Using Different Acquisition Sequences and Calculation Methods at 1.5 Tesla

Mars¹,

Chelli²,

Tbini³

et al. 2018

Med Princ Pract

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“…1). Then, m(0) and σ(0) at the zero echo time are estimated by the mono-exponential model [8,9] (red curves in Fig. 1).…”

Section: Multi-echo Based Noise Removing Methodsmentioning

confidence: 99%

“…The global mean and the standard deviation at the zero echo time, m(0) and σ(0), are estimated using the method proposed by Koff et al [8].…”

Section: Multi-echo Based Noise Removing Methodsmentioning

confidence: 99%

A novel noise removal using homomorphic normalization for multi-echo knee MRI

Cui

Kim

Hong

et al. 2011

IEICE Electron. Express

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This paper presents a novel approach for removing noise from multi-echo knee magnetic resonance images using global intensity normalization and the averaging operation along the echo-time. Firstly, the global mean and standard deviation at the zero echo-time are estimated by applying the mono-exponential spin echo model to the means and standard deviations of multi-echo images. Secondly, the signal and noise levels at multi-echo images are normalized to the estimated mean and standard deviation at the zero echo-time. Then, the normalized multi-echo images are averaged along the echo-time into a noise-removed zero echo-time image. Finally, the multi-echo MR images are reconstructed from the noise-removed zero echo-time image by the inverse normalization. The experiments demonstrate that the proposed method effectively removes not only the noises of each multi-echo image but also noises of the Quantitative T2 image.

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“…To solve the equation for T2 and S 0 , different fitting methods such as linear least squares, weighted linear least squares, or nonlinear least squares algorithms were used in the past [10,20]. The chosen fitting method has a considerable impact on the resulting T2 values, thus making the comparison of T2 values of different studies using different fitting methods difficult.…”

Section: T2 Relaxation Time Measurementsmentioning

confidence: 99%

“…Various possibilities for the number and values of the echo times (TE) were reported. To give an example, the Osteoarthritis Initiative (OAI), which had 4,796 study participants, used a multislice multiecho (MSME) spin echo sequence with seven echoes (TE = 10,20,30,40,50,60, and 70 ms), repetition time (TR) of 2,700 ms, and total acquisition time of 10.6 min [9].Compared to single-echo spin echo and single-slice multiecho spin echo sequences, the application of a MSME spin echo sequence considerably reduces the acquisition time. This is important for the feasibility of quantitative T2 relaxation time measurements in clinical practice.…”

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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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Bias of cartilage T2 values related to method of calculation

Cited by 34 publications

References 41 publications

MRI T2 Mapping of Knee Articular Cartilage Using Different Acquisition Sequences and Calculation Methods at 1.5 Tesla

MRI T2 Mapping of Knee Articular Cartilage Using Different Acquisition Sequences and Calculation Methods at 1.5 Tesla

A novel noise removal using homomorphic normalization for multi-echo knee MRI

MR T2 Relaxation Time Measurements for Cartilage and Menisci

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