{"title":"磁化传递可以解释磁共振成像文献中大部分的 $T_1$ 变异。","authors":"Jakob Assländer","doi":"","DOIUrl":null,"url":null,"abstract":"<p><strong>Purpose: </strong>To identify the predominant source of the <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> variability described in the literature, which ranges from 0.6-1.1s for brain white matter at 3T.</p><p><strong>Methods: </strong>25 <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> -mapping methods from the literature were simulated with a mono-exponential and magnetization-transfer (MT) models, each followed by mono-exponential fitting. A single set of model parameters was assumed for the simulation of all methods, and these parameters were estimated by fitting the simulation-based to the corresponding literature <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> values of white matter at 3T.</p><p><strong>Results: </strong>Mono-exponential simulations suggest good inter-method reproducibility and fail to explain the highly variable <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> estimates in the literature. In contrast, MT simulations suggest that a mono-exponential fit results in a variable <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> and explain up to 62% of the literature's variability.</p><p><strong>Conclusion: </strong>The results suggest that a mono-exponential model does not adequately describe longitudinal relaxation in biological tissue. Therefore, <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> in biological tissue should be considered only a <i>semi-quantitative</i> metric that is inherently contingent upon the imaging methodology; and comparisons between different <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> -mapping methods and the use of simplistic spin systems-such as doped-water phantoms-for validation should be viewed with caution.</p>","PeriodicalId":93888,"journal":{"name":"ArXiv","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11419191/pdf/","citationCount":"0","resultStr":"{\"title\":\"<ArticleTitle xmlns:ns0=\\\"http://www.w3.org/1998/Math/MathML\\\">Magnetization transfer explains most of the <ns0:math> <ns0:mrow><ns0:msub><ns0:mi>T</ns0:mi> <ns0:mn>1</ns0:mn></ns0:msub> </ns0:mrow> </ns0:math> variability in the MRI literature.\",\"authors\":\"Jakob Assländer\",\"doi\":\"\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Purpose: </strong>To identify the predominant source of the <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> variability described in the literature, which ranges from 0.6-1.1s for brain white matter at 3T.</p><p><strong>Methods: </strong>25 <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> -mapping methods from the literature were simulated with a mono-exponential and magnetization-transfer (MT) models, each followed by mono-exponential fitting. A single set of model parameters was assumed for the simulation of all methods, and these parameters were estimated by fitting the simulation-based to the corresponding literature <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> values of white matter at 3T.</p><p><strong>Results: </strong>Mono-exponential simulations suggest good inter-method reproducibility and fail to explain the highly variable <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> estimates in the literature. In contrast, MT simulations suggest that a mono-exponential fit results in a variable <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> and explain up to 62% of the literature's variability.</p><p><strong>Conclusion: </strong>The results suggest that a mono-exponential model does not adequately describe longitudinal relaxation in biological tissue. Therefore, <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> in biological tissue should be considered only a <i>semi-quantitative</i> metric that is inherently contingent upon the imaging methodology; and comparisons between different <math> <mrow><msub><mi>T</mi> <mn>1</mn></msub> </mrow> </math> -mapping methods and the use of simplistic spin systems-such as doped-water phantoms-for validation should be viewed with caution.</p>\",\"PeriodicalId\":93888,\"journal\":{\"name\":\"ArXiv\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11419191/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ArXiv\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ArXiv","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Magnetization transfer explains most of the T1 variability in the MRI literature.
Purpose: To identify the predominant source of the variability described in the literature, which ranges from 0.6-1.1s for brain white matter at 3T.
Methods: 25 -mapping methods from the literature were simulated with a mono-exponential and magnetization-transfer (MT) models, each followed by mono-exponential fitting. A single set of model parameters was assumed for the simulation of all methods, and these parameters were estimated by fitting the simulation-based to the corresponding literature values of white matter at 3T.
Results: Mono-exponential simulations suggest good inter-method reproducibility and fail to explain the highly variable estimates in the literature. In contrast, MT simulations suggest that a mono-exponential fit results in a variable and explain up to 62% of the literature's variability.
Conclusion: The results suggest that a mono-exponential model does not adequately describe longitudinal relaxation in biological tissue. Therefore, in biological tissue should be considered only a semi-quantitative metric that is inherently contingent upon the imaging methodology; and comparisons between different -mapping methods and the use of simplistic spin systems-such as doped-water phantoms-for validation should be viewed with caution.