MRI Biomarker Proton Spin Relaxation Times

1 Page 1 NIST Special Publication 250-97 Magnetic Resonance Imaging Biomarker Calibration Service: Proton Spin Relaxation Times Michael A. Boss Andrew M. Dienstfrey Zydrunas Gimbutas Kathryn E. Keenan Anthony B. Kos Jolene D. Spl... Open at page → 2 Page 2 NIST Special Publication 250-97 Magnetic Resonance Imaging Biomarker Calibration Service: Proton Spin Relaxation Times Michael A. Boss Kathryn E. Keenan Karl F. Stupic Stephen E. Russek Applied Physics Division Physical... Open at page → 3 Page 3 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedural or concept adequately. Such identification is not intended to imply recommendation o... Open at page → 4 Page 4 i This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Abstract This document describes a calibration service to measure proton spin relaxation times, T 1 and T 2, of materials us... Open at page → 5 Page 5 ii This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Table of Contents 1. Introduction ............................................................................................ Open at page → 6 Page 6 iii This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Fig. 2. Schematic diagram of the NIST NMR measurement system .................................................... 8 Fig. 3... Open at page → 7 Page 7 1 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 1. Introduction This calibration service provides traceable measurements of the proton spin 1 relaxation times, T 1 and T 2,... Open at page → 8 Page 8 2 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 and after the shimming. The NMR RF power calibration is done before each series of measurements using nutation experiments d... Open at page → 9 Page 9 3 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 the local fields produced by the sample, ???????????? �⃗ 1(????????????) is the applied time dependent RF fields, ??????????... Open at page → 10 Page 10 4 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 The first term, 1 ???????????? 2′ , is usually thought of as encompassing extrinsic dephasing processes; the second, 1 ?????... Open at page → 11 Page 11 5 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 frequency that is the difference between the transmit frequency and the receiver local oscillator frequency. The data are th... Open at page → 12 Page 12 6 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 into the transverse plane using a 90° excitation pulse. A series of 180° pulses are then applied with a time interval τcp be... Open at page → 13 Page 13 7 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 we accept the data. If these two conditions are not met, we will reject the data set as not being describable by a simple ex... Open at page → 14 Page 14 8 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Fig. 2. Schematic diagram of the NIST NMR measurement system. 4.1 NMR system The NMR system, shown in Fig. 2, was assembled... Open at page → 15 Page 15 9 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 returning to the desired set point. The resonance of a test sample is measured as the field approaches the desired value in... Open at page → 16 Page 16 10 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 fit to the nutation curve assuming a trapezoidal RF field profile shown in Fig. 3b. The model predicts a signal given by: ?... Open at page → 17 Page 17 11 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 rest on top of the NMR probe. The temperature is controlled by a proportional -integral-derivative (PID) control system tha... Open at page → 18 Page 18 12 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 shown in Fig. 5. The insertion depth of the NMR tube was adjusted s o that the center of the RF coil i s 7 mm above the bas... Open at page → 19 Page 19 13 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 y′ x′ y′ -x′ -x′ -y′ -x′ -y′ -x′ -x′ y′ x′ y′ y′ y′ -y′ -x′ -y′ y′ y′ y′ x′ y′ -y′ -y′ -y′ -x′ -y′ -y′ -y′ Carr-Purcell-Mei... Open at page → 20 Page 20 14 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 where 0.0054 is the standard deviation of the three T 1 values. The coefficient of variation (standard deviation over the m... Open at page → 21 Page 21 15 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 of-fit test is 0.0045. There is a small deviation in the uniformity of the residuals at small times, indicating the possibl... Open at page → 22 Page 22 16 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 For Type A uncertainty evaluations, we assume that measurements are independent and normally distributed. For example, the... Open at page → 23 Page 23 17 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 6.1. Overview of Measurement System Uncertainties The sources of uncertainty for the T 1 and T 2 measurements are indicated... Open at page → 24 Page 24 18 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Fig. 8. NMR system schematic with labeled sources of uncertainty Time b ase (TC1) and time jitter (TC2) Proton relaxation t... Open at page → 25 Page 25 19 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 given proper calibration and maintenance of the NMR system, is not a major contributor to the total uncertainty. The accura... Open at page → 26 Page 26 20 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 in the uncertainty calculation by applying a G aussian distribution of RF power amplitudes with a worst-case standard devia... Open at page → 27 Page 27 21 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Environmental noise (LE4): Environmental noise is due to RF radiation or low frequency magnetic field fluctuations coming f... Open at page → 28 Page 28 22 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Diffusion of water in an inhomogeneous field can lead to additional dephasing of the proton spins. The shim on the NMR insu... Open at page → 29 Page 29 23 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 The first/inner loop integrates over a large ensemble of spin packets, typically 10 5 , where B 0 and B 1 are determined fr... Open at page → 30 Page 30 24 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Fig. 10. T 1 and T 2 distributions from Monte Carlo calculations varying all parameters for N = 100 trials. The input T 1 a... Open at page → 31 Page 31 25 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 however, when combined with other uncertainties, it may lead to a large contribution to measurement bias and standard devia... Open at page → 32 Page 32 26 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Table 2. Results of Monte Carlo calculations of bias (mean) and standard deviation associated with T 1, T2 measurements. Th... Open at page → 33 Page 33 27 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 9. Summary NIST provides a measurement service to determine the proton spin relaxation times, T 1 and T 2, of solutions use... Open at page → 34 Page 34 28 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 References 1. L. G. Kessler et al., The emerging science of quantitative imaging biomarkers terminology and definitions for... Open at page → 35 Page 35 29 This publication is available free of charge from: https://doi.org /10.6028/NIST.SP. 250 - 97 Appendix A: Lack of Fit Test An F-statistic is calculated from a ratio of the sum -of-squares due to lack of fit (SSLF) to... Open at page →