scholarly journals Diffusion-weighted Magnetic Resonance Imaging: What Makes Water Run Fast or Slow?

2011 ◽  
Vol 1 ◽  
pp. 27 ◽  
Author(s):  
Francesca Fornasa
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Extracellular Space ◽  
Water Diffusion ◽  
Brownian Diffusion ◽  
Water Molecules ◽  
Resonance Imaging ◽  
Diffusion Weighted ◽  
Pictorial Essay ◽  
Weighted Magnetic Resonance Imaging

Diffusion-Weighted Magnetic Resonance Imaging (DWI) obtains information useful in diagnosing several diseases through the measurement of random, Brownian diffusion of water molecules in tissues. This pictorial essay illustrates the main factors, i.e., ratio between the volume occupied by cells and the extracellular space, composition of the extracellular space, and temperature, that determine the rate of the water diffusion. The mechanism through which these influencing factors affect water diffusion is explained. Clinical and experimental examples, derived both from physiology and from non-human models, are described.

Early Detection of Response to Radiation Therapy in Patients With Brain Malignancies Using Conventional and High b-Value Diffusion-Weighted Magnetic Resonance Imaging

2003 ◽  
Vol 21 (6) ◽  
pp. 1094-1100 ◽  
Author(s):  
Yael Mardor ◽  
Raphael Pfeffer ◽  
Roberto Spiegelmann ◽  
Yiftach Roth ◽  
Stephan E. Maier ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Radiation Therapy ◽  
Magnetic Resonance ◽  
Tumor Response ◽  
Bound Water ◽  
Water Molecules ◽  
Resonance Imaging ◽  
Diffusion Weighted ◽  
Diffusion Parameters ◽  
Weighted Magnetic Resonance Imaging

Purpose: To study the feasibility of using diffusion-weighted magnetic resonance imaging (DWMRI), which is sensitive to the diffusion of water molecules in tissues, for detection of early tumor response to radiation therapy; and to evaluate the additional information obtained from high DWMRI, which is more sensitive to low-mobility water molecules (such as intracellular or bound water), in increasing the sensitivity to response. Patients and Methods: Standard MRI and DWMRI were acquired before and at regular intervals after initiating radiation therapy for 10 malignant brain lesions in eight patients. Results: One week posttherapy, three of six responding lesions showed an increase in the conventional DWMRI parameters. Another three responding lesions showed no change. Four nonresponding lesions showed a decrease or no change. The early change in the diffusion parameters was enhanced by using high DWMRI. When high DWMRI was used, all responding lesions showed increase in the diffusion parameter and all nonresponding lesions showed no change or decrease. Response was determined by standard MRI 7 weeks posttherapy. The changes in the diffusion parameters measured 1 week after initiating treatment were correlated with later tumor response or no response (P < .006). This correlation was increased to P < .0006 when high DWMRI was used. Conclusion: The significant correlation between changes in diffusion parameters 1 week after initiating treatment and later tumor response or no response suggests the feasibility of using DWMRI for early, noninvasive prediction of tumor response. The ability to predict response may enable early termination of treatment in nonresponding patients, prevent additional toxicity, and allow for early changes in treatment.

scholarly journals Restricted Water Diffusion in Diffusion-Weighted Magnetic Resonance Imaging in Pancreatic Cancer is Associated with Tumor Hypoxia

Cancers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 89
Author(s):  
Philipp Mayer ◽  
Anne Kraft ◽  
Hagen R. Witzel ◽  
Nicole Marnet ◽  
Nina Hörner ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pancreatic Cancer ◽  
Magnetic Resonance ◽  
B Lymphocyte ◽  
Close Association ◽  
Tumor Hypoxia ◽  
Water Diffusion ◽  
Resonance Imaging ◽  
Diffusion Weighted ◽  
Weighted Magnetic Resonance Imaging

Hypoxia is a hallmark of pancreatic cancer (PDAC) due to its compact and extensive fibrotic tumor stroma. Hypoxia contributes to high lethality of this disease, by inducing a more malignant phenotype and resistance to radiation and chemotherapy. Thus, non-invasive methods to quantify hypoxia could be helpful for treatment decisions, for monitoring, especially in non-resectable tumors, or to optimize personalized therapy. In the present study, we investigated whether tumor hypoxia in PDAC is reflected by diffusion-weighted magnetic resonance imaging (DW-MRI), a functional imaging technique, frequently used in clinical practice for identification and characterization of pancreatic lesions. DW-MRI assesses the tissue microarchitecture by measuring the diffusion of water molecules, which is more restricted in highly compact tissues. As reliable surrogate markers for hypoxia, we determined Blimp-1 (B-lymphocyte induced maturation protein), a transcription factor, as well as vascular endothelial growth factor (VEGF), which are up-regulated in response to hypoxia. In 42 PDAC patients, we observed a close association between restricted water diffusion in DW-MRI and tumor hypoxia in matched samples, as expressed by high levels of Blimp-1 and VEGF in tissue samples of the respective patients. In summary, our data show that DW-MRI is well suited for the evaluation of tumor hypoxia in PDAC and could potentially be used for the identification of lesions with a high hypoxic fraction, which are at high risk for failure of radiochemotherapy.

scholarly journals Assessment of lacrimal glands in thyroid eye disease with diffusion-weighted magnetic resonance imaging

2019 ◽  
Vol 84 ◽  
pp. 142-146 ◽  
Author(s):  
Ahmed Razek ◽  
El-hadidy Mohamed El-Hadidy ◽  
Mohamed El-Said Moawad ◽  
Nader El-Metwaly ◽  
Amr Abd El-hamid El-Said
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Thyroid Eye Disease ◽  
Eye Disease ◽  
Resonance Imaging ◽  
Lacrimal Glands ◽  
Diffusion Weighted ◽  
Weighted Magnetic Resonance Imaging
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