1、BSI Standards Publication PD ISO/TR 16379:2014 Tissue-engineered medical products Evaluation of anisotropic structure of articular cartilage using DT (Diffusion Tensor)-MR ImagingPD ISO/TR 16379:2014 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of ISO/TR 1637
2、9:2014. The UK participation in its preparation was entrusted to Technical Committee RGM/1, Regenerative medicine. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contrac
3、t. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 82564 4 ICS 11.040.40 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the
4、 authority of the Standards Policy and Strategy Committee on 31 May 2014. Amendments/corrigenda issued since publication Date T e x t a f f e c t e dPD ISO/TR 16379:2014 ISO 2014 Tissue-engineered medical products Evaluation of anisotropic structure of articular cartilage using DT (Diffusion Tensor)
5、MR Imaging Produits mdicaux base de tissus valuation de la structure anisotrope du cartilage articulaire en utilisant limagerie en tenseur de diffusion (IRM-TD) TECHNICAL REPORT ISO/TR 16379 First edition 2014-03-01 Reference number ISO/TR 16379:2014(E)PD ISO/TR 16379:2014ISO/TR 16379:2014(E)ii ISO
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8、shed in SwitzerlandPD ISO/TR 16379:2014ISO/TR 16379:2014(E) ISO 2014 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 T erms and definitions . 1 3 Principle 3 4 Diffusion tensor magnetic resonance imaging (DT-MRI) data observation in articular cartilage 3 4.1 DT-MRI mea
9、surement process 3 4.2 Notes on setting of DT-MRI imaging parameters for articular cartilage . 4 4.3 Measurement indices for structural evaluation of articular cartilage by DT-MRI 5 Annex A (informative) Measurement Results 10 Bibliography .23PD ISO/TR 16379:2014ISO/TR 16379:2014(E) Foreword ISO (th
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16、ttee responsible for this document is ISO/TC 150, Implants for Surgery, Subcommittee SC 7, Tissue-engineered Medical Products.iv ISO 2014 All rights reservedPD ISO/TR 16379:2014ISO/TR 16379:2014(E) Introduction Structural evaluation of articular cartilage with conventional diagnostic technologies is
17、 challenging, and Nihon University has developed technologies (see Reference 1) and collected relevant data for in vivo evaluation of articular cartilage structure by means of diffusion tensor magnetic resonance imaging (DT-MRI) using 1,5 Tesla or 3 Tesla MRI equipment employed for treatment in hosp
18、ital settings. These data are released in this Technical Report prepared for reference in treatment settings. This work is part of “Development of Cartilage Observation and Evaluation Technologies for Regenerative Medicine Processes”, an activity managed by the University under “Development of Evalu
19、ation Technology for Early Introduction of Regenerative Medicine”, a project contracted by the New Energy and Industrial Technology Development Organization (NEDO) to the National Institute of Advanced Industrial Science and Technology (AIST) and its Technology Research Association of Medical Welfar
20、e Apparatus. ISO 2014 All rights reserved vPD ISO/TR 16379:2014PD ISO/TR 16379:2014Tissue-engineered medical products Evaluation of anisotropic structure of articular cartilage using DT (Diffusion Tensor)-MR Imaging 1 Scope This Technical Report has been prepared for evaluation of therapeutic course
21、s for articular cartilage disease and summarizes results from structural evaluation of knee joint cartilage by diffusion tensor imaging, an MRI applied technology allowing non-invasive observation of soft tissue morphology in vivo. This Technical Report is intended for use in areas such as regenerat
22、ive medicine for knee joint cartilage disease. After in vivo transplant of cartilage cells or tissue as a regenerative treatment, longitudinal diagnosis is needed to assess regeneration as articular cartilage, but arthroscopes used primarily for this purpose are invasive and also do not allow evalua
23、tion of structure by simple observation of surfacial characteristics. Radiography and CT do not visualize articular cartilage and also entail the problem of exposure. Collagen fibres, the primary component of articular cartilage, have a surfacial layer parallel to the articular surface to serve a lu
24、bricating function for the articular surface, a middle layer with a randomized structure to distribute loads, and deep layers oriented vertically to support loads. The anisotropy of this three-layer structure is a characteristic feature of hyaline cartilage structures and a mechanism demonstrating a
25、 lubricating function for articular cartilage. We can then ask whether articular cartilage can be assessed by evaluating the anisotropy of collagen. MRI techniques allow non-invasive visualization of soft tissue form and function in vivo, and DT-MRI conveys the direction of water molecule motion. In
26、 fibrous tissues, the direction of water molecule motion is restricted to the direction of fibre orientation; consequently, the direction of water molecule motion matches that of fibre orientation. The use of DT-MRI therefore does allow evaluation of collagen fibre orientation and anisotropy in arti
27、cular cartilage. DT-MRI is thus used to observe articular cartilage anisotropy data for use as standardized data in longitudinal diagnosis following transplant of articular cartilage as a regenerative treatment. 2 T erms a nd definiti ons For the purposes of this document, the following terms and de
28、finitions apply. 2.1 diffusion tensor DT tensor expressing the orientation and magnitude of diffused proton signals 2.2 sequence protocol for performance of MRI 2.3 spin-echo echo-planar imaging SE-EPI method of high-speed imaging in which gradient fields are flipped continuously at high speed to pr
29、oduce echoes continuously by means of a spin-echo pulse sequence TECHNICAL REPORT ISO/TR 16379:2014(E) ISO 2014 All rights reserved 1PD ISO/TR 16379:2014ISO/TR 16379:2014(E) 2.4 f ie ld of v iew FOV width and height of an imaged region (expressed in cm or mm) 2.5 matrix pixel resolution for acquisit
30、ion of MR signals in a field of view 2.6 echo time TE time after RF pulse application until an echo is produced SOURCE: JIS K 3611 2.7 radio frequency pulse RF pulse short duration, high-frequency electromagnetic wave in pulse form SOURCE: JIS K 3611 2.8 repetition time TR time interval for repetiti
31、on of the basic unit of magnetic resonance pulse sequences SOURCE: JIS K 3611 2.9 slice thickness thickness of the imaging plane 2.10 number of averages NA number of times an identical MR signal is repeated 2.11 b value maximum value of the parameter indicating level of diffusion weighting 2.12 moti
32、on probing gradient MPG gradient field applied to detect diffusion 2.13 parallel imaging high-speed imaging method making use of the difference in sensitivities provided by multiple coils 2.14 fractional anisotropy FA number indicating level of structural anisotropy 2.15 mean diffusivity MD mean of
33、diffusion coefficients along the three primary axes of a diffusion tensor2 ISO 2014 All rights reservedPD ISO/TR 16379:2014ISO/TR 16379:2014(E) 2.16 signal-to-noise ratio SNR value expressing the proportion of signal to noise; greater values indicate higher image quality 2.17 voxel three-dimensional
34、 cuboid representing the minimum unit comprising a three-dimensional image 3 Principle In the regeneration medicine for artificial cartilage, it is important to evaluate whether the implanted tissues regenerate as an artificial cartilage with time. However, an arthroscope is invasive and only monito
35、rs the surface texture of articular cartilage. X-ray and CT cannot project the cartilage tissue and have an exposure problem. An articular cartilage has anisotropy by differential orientation of collagen fibra to exert a lubrication property as a joint. In the superficial layer, collagen fibra is or
36、iented to parallel on joint surface. Next, in the middle layer, collagen fibra was in random for distribution of loading and oriented vertically in deep layer. Such three-layer structure is a feature of articular cartilage, which is based on the biomechanical property of articular cartilage. Thus, i
37、t is possible to evaluate whether or not the articular cartilage by observation of the anisotropy structure. In DT-MRI, in MRI techniques, it is possible to know the direction of proton movement. In fibrotic tissues, as the direction of water molecule movement is limited along the orientation of col
38、lagen fibro, the fibro direction is consistent with the direction of proton movement. Therefore, the direction of collagen structure can be evaluated with DT-MRI. In this draft, DT-MRI data obtained from healthy male by using several MR devices shows for use as reference data to evaluate the process
39、 after regenerate treatment of articular cartilage. 4 Diffusion tensor magnetic resonance imaging (DT-MRI) data observation in articular cartilage 4.1 DT-MRI measurement process The process shown in the flowchart in Figure 1 is used for acquisition, measurement, and observation of data to evaluate a
40、rticular cartilage structure. This Technical Report envisions that different models of MRI equipment are used in different hospital facilities, and thus observational data are shown for three types of MRI apparatus produced by different manufacturers. Table 1 presents the MRI apparatus, signal-recei
41、ving coils, and imaging parameters used in observation. ISO 2014 All rights reserved 3PD ISO/TR 16379:2014ISO/TR 16379:2014(E) Figure 1 DT-MRI data measurement process Table 1 MRI apparatus, signal-receiving coils, and imaging parameters used in DT-MRI Imaging facility Kyoto University Institute for
42、 Frontier Medical Sciences Nihon University School of Dentistry at Matsudo Hospital Hiroshima University Hospital Apparatus (Manufacturer) SONATA 1,5T (Siemens) Achieva 1,5T (Philips) Signa Excite 3T (General Electric) Signal-receiving coil 4 ch flex array 8 ch sense knee Lower extremity Sequence SE
43、EPI SE-EPI SE-EPI FOV mm 192 192 150 150 128 128 Matrix 192 192 144 142 128 128 TR ms 2 200 2 200 2 200 TE ms 70 68 68 Slice thickness mm 3 5 5 Number of averages 24 20 12 b-value 600 600 400 No. MPG axes 6 6 6,15 Parallel imaging GR APPA a SENSE b n/a Image slice Sagittal plane Sagittal plane Sagi
44、ttal plane Pixels 384 384 400 400 256 256 aGeneralized rapid acquisition with partially parallel acquisition. bSensitivity encoding. 4.2 Notes on setting of DT-MRI imaging parameters for articular cartilage 4.2.1 Imaging resolution The resolution at which MR signals are acquired corresponds to a vox
45、el size determined by matrix and slice thickness. Larger voxel sizes correspond to higher SNR, which also increases data reliability. Conversely, smaller voxel sizes increase resolution but decreased SNR of MR signals, which decreases data reliability.4 ISO 2014 All rights reservedPD ISO/TR 16379:20
46、14ISO/TR 16379:2014(E) Because articular cartilage has a three-layer structure with differing collagen fibre orientations (see Reference 2), the matrix and slice thickness parameters used for this Technical Report were selected to allow acquisition of three-layer data. 4.2.2 Repetition time Longer T
47、R increases the number of slices in an image but lengthens imaging time. The parameter in this Technical Report was selected based on Reference 1. 4.2.3 Number of averages A greater number of signal averages raises SNR and also increases data reliability but lengthens imaging time. The parameter in
48、this Technical Report was selected based on Reference 1. 4.2.4 b-value Higher b-values lengthen TE, which might lead to under-representation of diffusivity. Conversely, lower b-values can lead to over representation of diffusivity, and this parameter shall be set with consideration for the imaging t
49、arget. The parameter in this Technical Report was selected based on Reference 1. 4.2.5 Motion probing gradient (MPG) MPG shall be applied in a minimum of six directions to determine diffusion tensors. As MPG is applied to more axes, more complex structures can be analysed, but imaging time lengthens. But for application of MPG to equal numbers of axes, a higher static field intensity of the MRI apparatus will shorten imaging time. In consideration of the imaging times envisioned in hospital use,
