量化MRI分析：保罗·托夫特的医学成像测量原理

需积分: 9 193 浏览量更新于2024-11-07 1 收藏 136KB PDF 举报

"Paul S. Tofts所著的'quantitative MRI chapter1'，主要讨论了定量磁共振成像在脑部疾病中的应用及其测量原理。本书关注的是测量科学与MRI技术的结合，旨在实现对特定量的精确、准确且方便的测量。书中涉及测量科学的历史、医学成像中的测量概念等主题。" 正文： 1.1 引言在医学领域，尤其是神经科学中，定量磁共振成像（Quantitative MRI，简称qMRI）已经成为研究和诊断疾病的重要工具。Paul S. Tofts在其著作中强调了测量科学与MRI的结合，这一结合使得我们能够更深入地了解和监测由疾病引起的大脑变化。通过qMRI，研究人员和医生可以非侵入性地获取大脑组织的生理和生物化学信息，从而提高诊断的准确性和治疗效果。 1.2 测量的历史测量科学有着悠久的历史，而MRI技术自20世纪80年代以来已经发展迅速。这两者的融合意味着我们可以利用先进的技术来测量大脑的复杂特性，如组织的水分含量、扩散特性、代谢率等，这些测量结果对于理解疾病的进展和治疗反应至关重要。 1.3 医学成像中的测量概念在医学成像中，测量不仅仅涉及图像的质量和解析度，还涉及到如何量化和解释图像数据。Tofts讨论了诸如准确性、精确度和可重复性等关键概念，这些都是确保测量结果可靠性的基础。此外，他还可能探讨了校准、标准化以及如何减少测量误差等主题，这对于在不同实验室和设备之间进行比较和交流至关重要。书中可能还涵盖了MRI的基本原理，包括核磁共振（NMR）现象、磁共振信号的产生和检测，以及如何通过改变成像参数来获取定量信息。此外，可能还会涉及不同的qMRI技术，如T1、T2弛豫时间测量、扩散张量成像（DTI）、磁化传递成像（MTI）和弥散峰度成像（DKI）等，这些技术提供了关于大脑组织结构和功能的多维度洞察。在临床应用方面，qMRI被广泛用于识别早期病变、评估疾病进展、监测治疗反应以及研究正常生理过程。例如，在神经退行性疾病（如阿尔茨海默病）、脑肿瘤、脑血管疾病和创伤性脑损伤的研究中，qMRI提供了无创性的生物标记物。 "quantitative MRI chapter1"不仅探讨了测量科学在MRI技术中的应用，还可能深入到具体的技术细节、实际应用案例以及未来的发展趋势，对理解和提升定量MRI在医学研究和实践中的价值具有重要意义。通过理解这些概念和技术，研究人员和临床医生能够更好地利用qMRI来促进疾病的早期发现和有效治疗。

4 Quantitative MRI of the Brain

Concepts of measurement in MRI – an

overview

• qMR uses the paradigms of a scientiﬁc

instrument

• measurement traditions have a long history,

from astronomy and watchmaking

• good study design often gives results worth

publishing

again, and also to be comparable with measure-

ments made by others in other locations. In the

human body we expect to measure some param-

eters (height, weight, blood pressure) ourselves,

recognizing that some of these parameters may

have genuine biological variation with time. More

invasive measurements (e.g. blood alcohol level

or blood sugar level) are also expected to have a

well-deﬁned normal range, and to be reproducible.

In physics, chemistry, electrical engineering and

manufacturing there is a strong tradition of mea-

surement, international agreements on standards,

and training courses for laboratory practitioners.

International standards of mass, length and time

have been in existence for many years. Secondary

standards have been produced which can be traced

back to the primary standards. National and inter-

national bodies provide coordination.

As individual scientists we may have a pas-

sionate desire to use our talents for the beneﬁt of

mankind, preferring to devote our energy to ﬁnd-

ing better ways of helping our fellow humans to

be healthy than to improving weapons for their

destruction. In this context, developing measure-

ment techniques in MRI constitutes a perfect appli-

cation of traditional scientiﬁc skills to a mod-

ern problem.

MRI is now widespread, and accepted as the

imaging method of choice for the brain (and

for many body studies). It is generally used in

a qualitative way, with a radiologist interpreting

(reporting) ﬁlm hardcopy on a light box.

Many

A light box illuminates from behind a ﬁlm (size approx-

imately 14 × 17 inches, or 35 × 43 cm), which may contain

MRI machines now have independent workstations

connected to the scanner and the database of MR

images, which enable and encourage simple quan-

titative analysis of the images in their numerical

(i.e. digital) form. However the data collection pro-

cedure often prevents proper quantiﬁcation being

carried out; machine parameters such as transmit-

ter gain, ﬂip angle value (and its spatial variation),

receiver gain and image scaling may all be accept-

able for qualitative analysis, but cause irreversible

confusion in images to be quantiﬁed. Researchers

may be unaware of good practice in quantiﬁcation,

and collect or analyse data in an unsuitable way,

even though the MRI machine is capable of more.

The process of quantifying, or measuring,

parameters in the brain necessarily takes more

time and effort than a straightforward qualitative

study. More MRI scanner time is needed, and

considerable physics development effort and

computing resources may be needed to set up

the procedure. In addition, analysis can be very

time-consuming, and support of the procedure is

required to measure and maintain its reliability

over time. Procedures have to be found

which

are insensitive to operator inﬂuence (whether in

the data collection or image analysis) and to

scanner imperfections (such as radiofrequency

nonuniformity from a particular head coil), which

provide good coverage of the brain in a reasonable

time, and which are stable over study times which

may extend to decades.

The beneﬁts of quantiﬁcation are that funda-

mental research into biological changes in disease,

and their response to potential treatments, can pro-

ceed in a more satisfactory way. Problems of bias,

reproducibility and interpretation are substantially

reduced. MRI can move from a process of picture-

taking, where reports are made on the basis of

unusually bright, dark, small or large objects, to

traditional X-ray images or several MR images. As MRI pro-

duces progressively more slices per study (a three-dimensional

image dataset may contain 128 slices), the desire to print

these all onto a few ﬁlms has resulted in progressively smaller

images, in which the relevant detail cannot be seen without

using a magniﬁer.

The author’s website (www.qmri.org) contains more links

and references to qMR.

剩余13页未读，继续阅读

fogmen

粉丝: 3
资源: 4

量化MRI分析：保罗·托夫特的医学成像测量原理

quantitative MRI chapter2

quantitative MRI chapter3

FRM Part 1 Quantitative

quantitative investment

GMAT quantitative

Quantitative trading

Quantitative-analysis

Applied Quantitative Finance

Quantitative Trading Strategies

Quantitative Feedback Theory电子书

最新资源