Book contents
- Frontmatter
- Contents
- Contributors
- Case studies
- Preface to the second edition
- Preface to the first edition
- Abbreviations
- Introduction
- Section 1 Physiological MR techniques
- Chapter 1 Fundamentals of MR spectroscopy
- Chapter 2 Quantification and analysis in MR spectroscopy
- Chapter 3 Artifacts and pitfalls in MR spectroscopy
- Chapter 4 Fundamentals of diffusion MR imaging
- Chapter 5 Human white matter anatomical information revealed by diffusion tensor imaging and fiber tracking
- Chapter 6 Artifacts and pitfalls in diffusion MR imaging
- Chapter 7 Cerebral perfusion imaging by exogenous contrast agents
- Chapter 8 Detection of regional blood flow using arterial spin labeling
- Chapter 9 Imaging perfusion and blood–brain barrier permeability using T1-weighted dynamic contrast-enhanced MR imaging
- Chapter 10 Susceptibility-weighted imaging
- Chapter 11 Artifacts and pitfalls in perfusion MR imaging
- Chapter 12 Methodologies, practicalities and pitfalls in functional MR imaging
- Section 2 Cerebrovascular disease
- Section 3 Adult neoplasia
- Section 4 Infection, inflammation and demyelination
- Section 5 Seizure disorders
- Section 6 Psychiatric and neurodegenerative diseases
- Section 7 Trauma
- Section 8 Pediatrics
- Section 9 The spine
- Index
- References
Chapter 4 - Fundamentals of diffusion MR imaging
from Section 1 - Physiological MR techniques
Published online by Cambridge University Press: 05 March 2013
- Frontmatter
- Contents
- Contributors
- Case studies
- Preface to the second edition
- Preface to the first edition
- Abbreviations
- Introduction
- Section 1 Physiological MR techniques
- Chapter 1 Fundamentals of MR spectroscopy
- Chapter 2 Quantification and analysis in MR spectroscopy
- Chapter 3 Artifacts and pitfalls in MR spectroscopy
- Chapter 4 Fundamentals of diffusion MR imaging
- Chapter 5 Human white matter anatomical information revealed by diffusion tensor imaging and fiber tracking
- Chapter 6 Artifacts and pitfalls in diffusion MR imaging
- Chapter 7 Cerebral perfusion imaging by exogenous contrast agents
- Chapter 8 Detection of regional blood flow using arterial spin labeling
- Chapter 9 Imaging perfusion and blood–brain barrier permeability using T1-weighted dynamic contrast-enhanced MR imaging
- Chapter 10 Susceptibility-weighted imaging
- Chapter 11 Artifacts and pitfalls in perfusion MR imaging
- Chapter 12 Methodologies, practicalities and pitfalls in functional MR imaging
- Section 2 Cerebrovascular disease
- Section 3 Adult neoplasia
- Section 4 Infection, inflammation and demyelination
- Section 5 Seizure disorders
- Section 6 Psychiatric and neurodegenerative diseases
- Section 7 Trauma
- Section 8 Pediatrics
- Section 9 The spine
- Index
- References
Summary
The basics of diffusion
Brownian motion and diffusion
In 1827, when looking through a microscope at pollen grains from Clarkia pulchella, Robert Brown (a botanist from Montrose in Scotland) observed tiny particles within the grains that appeared to move randomly.[1] Intrigued by these movements (and with “essence of life” investigations in vogue), he examined pollen – even dead pollen – from other species and found the same random motion. We now know that the motion that Brown observed was not, of course, arising from the “essence of life” but was caused by bombardment of the pollen grains by gas molecules. This random molecular motion, often known as Brownian motion, and more frequently as diffusion, is the topic of this chapter.
Diffusion is an essential physical process for the normal functioning of living systems. For example, the transport of metabolites into cells is facilitated by diffusion. As we will see in later chapters, studying diffusion has the potential to provide insights into both cell physiology and cell structure. Unlike other MR parameters, such as the longitudinal and transverse relaxation time constants (T1 and T2), that are affected by experimental MR parameters, diffusion is an intrinsic property that is independent of the MR procedure employed to measure it.
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- Chapter
- Information
- Clinical MR NeuroimagingPhysiological and Functional Techniques, pp. 44 - 67Publisher: Cambridge University PressPrint publication year: 2009