Normal Brain and Brain Tumor: Multicomponent Apparent Diffusion Coefficient Line Scan Imaging

Maier, Stephan E.; Bogner, Péter; Bajzik, Gábor; Mamata, Hatsuho; Mamata, Yoshiaki; Romics, Imre; Jólesz, Ferenc A.; Mulkern, Robert V.

doi:10.1148/radiology.219.3.r01jn02842

Cited by 142 publications

(143 citation statements)

References 24 publications

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“…Models reflecting dynamic parameters, such as membrane restriction and permeability (27), and geometrical features (28) have been considered, but those distinct models lead to a diffusion signal decay which is nevertheless well approximated by a biexponential function (29)(30)(31)(32). Indeed, the estimates for the diffusion coefficients and the respective volume fractions of the SDP and FDP have been strikingly consistent across literature (33)(34)(35). Hence, unsurprisingly, the diffusion data that we obtained at different b values in a resting condition (Fig.…”

Section: Functional Diffusion Mrimentioning

confidence: 78%

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Bihan

Urayama

Aso

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

240

280

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Using MRI, we found that a slowly diffusing water pool was expanding (1.7 ؎ 0.3%) upon activation on the human visual cortex at the detriment of a faster diffusing pool. The time course of this water phase transition preceded the activation-triggered vascular response detected by usual functional MRI by several seconds. The observed changes in water diffusion likely reflect early biophysical events that take place in the activated cells, such as cell swelling and membrane expansion. Although the exact mechanisms remain to clarify, access to such an early and direct physiological marker of cortical activation with MRI will provide opportunities for functional neuroimaging of the human brain.ur current model of neuronal activation places great importance on transient electrical and biochemical events associated with the excitation processes. However, there is compelling evidence that activation is accompanied by other important physical phenomena. Microstructural changes in excited tissues have been observed, first from optical birefringence measurements (1, 2) and later more directly by using piezoelectric transducers (3). Those studies have revealed, for instance, that in the brain cell swelling is one of the physiological responses associated with neuronal activation (4, 5).However, such biophysical events have been monitored at the microscopic level by using invasive techniques in neuronal cell cultures or slices, and do not necessarily reflect physiological conditions (6, 7). Observing changes in cortical cell configuration in animals or humans would, thus, have a tremendous impact, because they would be directly linked to neuronal events, such as membrane expansion, and bridge the gap with current approaches to obtain images of human brain activation. Those approaches, such as blood oxygen level-dependent (BOLD) MRI, are based on blood flow changes and only indirectly and remotely related to cortical activation (8,9).A small decrease of the water diffusion coefficient during activation of human visual cortex has been previously reported by using diffusion MRI (10). Diffusion MRI provides valuable information on the microscopic obstacles which hinder diffusing molecules, such as membranes or macromolecules, and in turn, on the tissue cellular structure (11). Based on other MRI reports of water diffusivity decrease during intense neuronal activation (12, 13) or during other physiological or pathological conditions inducing cell swelling (14-17), the observed diffusion findings have been putatively ascribed to a transient swelling of cortical cells and a shrinking of the extracellular space, increasing its tortuosity (18) for diffusing molecules. However, no confirmation has been found so far for this mechanism. The aim of this report is to demonstrate that a decrease in water mobility can readily been observed in the human brain with diffusion MRI upon activation, and to provide evidence that this effect results from an early neuronal activation event that precedes the blood flow response by a sizeable time am...

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Section: Functional Diffusion Mrimentioning

confidence: 78%

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Bihan

Urayama

Aso

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

240

280

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“…Fast and slow diffusion components have been described in a human brain model, 34,35 and the fast diffusion components have been reported to be the main source of signal at a relatively low b-value, whereas the slow diffusion components dominate the signal intensity at a high b-value. 37 Increased cellularity of the tumor leads to a greater proportion of intracellular compared to extracellular water components, whereas decreased cellularity indicates a greater proportion of relatively easily diffusible extracellular water components. 38,39 Even though intracellular water components are not exactly the same as the slow diffusion components and extracellular water components are not the same as the fast diffusion components, the components are considered to correspond.…”

Section: Discussionmentioning

confidence: 99%

Squamous Cell Carcinoma of the Head and Neck: Comparison of Diffusion-weighted MRI at b-values of 1,000 and 2,000 s/mm<sup>2</sup> to Predict Response to Induction Chemotherapy

Ryoo

Kim

Choi

et al. 2015

MRMS

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Purpose: Recent publications have reported contradictory results of pretreatment diffusion-weighted magnetic resonance imaging (DWI) for the prediction of chemoradiotherapeutic response in primary squamous cell carcinomas of the head and neck (HNSCC). Therefore, we evaluated the diagnostic performance of DWI obtained with both standard (b = 0 and 1,000 s/mm 2 ) and high (b = 0 and 2,000 s/mm 2 ) b-values for predicting response to induction chemotherapy in HNSCCs.Methods: For 25 patients with primary HNSCC who underwent DWI with both standard and high b-values prior to treatment, we calculated corresponding apparent diffusion coefficient (ADC) maps. Regions of interest containing the tumor were drawn on every section of ADC maps and summated to make volume-based data of the entire tumor. Histogram parameters (mean ADC, kurtosis, and skewness) were correlated with treatment response using unpaired Student t test. Univariate and multivariate analysis of the ADC parameters, patient age, sex, whole tumor volume, and T stage were also performed to predict tumor response to induction chemotherapy.Results: Response to induction chemotherapy was good in 13 of the 25 patients and poor in 12. The mean ADC values of good responders at standard b-value (ADC 1000 ), 1.23 « 0.34 (© 10 ¹3 mm 2 /s), and high b-value (ADC 2000 ), 0.62 « 0.14 (© 10 ¹3 mm 2 /s), were lower than those of poor responders (ADC 1000 , 1.32 « 0.28 [© 10 ¹3 mm 2 /s]; ADC 2000 , 0.76 « 0.15 [© 10 ¹3 mm 2 /s]), but significant difference was achieved only at the ADC 2000 map (P = 0.02). In addition, mean tumor volume prior to treatment of good responders was smaller than that of poor responders. However, at multiple logistic regression analysis, only the mean ADC 2000 value remained as a significant predictor of response to induction chemotherapy.Conclusion: DWI with high b-values (b = 0 and 2,000 s/mm 2 ) as an assessment of ADC values may help predict tumor response to neoadjuvant chemotherapy for primary HNSCCs.

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“…Furthermore, the use of different b-values can lead to considerable variability in the calculated monoexponential ADC (14). Other models, such as the biexponential model and the stretched-exponential model (15,16), are more suitable to describe the admixture of multiple exponential signal decays, but they require data acquisition with additional b-values (thus prolonging scan time). Moreover, multiexponential analysis routines are usually not available in standard clinical software packages.…”

Section: Development Of Dwi: From the Brain To The Entire Bodymentioning

confidence: 99%

Complementary Roles of Whole-Body Diffusion-Weighted MRI and¹⁸F-FDG PET: The State of the Art and Potential Applications

Kwee¹,

Takahara²,

Ochiai³

et al. 2010

J Nucl Med

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18 F-FDG PET is an established functional imaging modality for the evaluation of human disease. Diffusion-weighted MRI (DWI) is another rapidly evolving functional imaging modality that can be used to evaluate oncologic and nononcologic lesions throughout the body. The information provided by 18 F-FDG PET and DWI can be complementary, because the 2 methods are based on completely different biophysical underpinnings. This article will describe the basic principles, clinical applications, and limitations of DWI. In addition, the available evidence that correlates and compares 18 F-FDG PET and DWI will be reviewed. PET,usi ng the radiotracer 18 F-FDG, is an established functional imaging modality for a variety of oncologic and nononcologic (e.g., inflammatory and infectious) applications (1-3). The contribution of 18 F-FDG PET to medicine has been unmatched by any other functional imaging modality (4). At present, there is also growing interest in the application of diffusion-weighted MRI (DWI) in the body (5-7). DWI allows visualization and quantification of the mobility of water molecules and has many potential clinical applications. Importantly, although 18 F-FDG PET and DWI are both functional imaging modalities and provide a high lesion-to-background contrast, they are based on completely different biophysical and biochemical underpinnings. Therefore, the information provided by the 2 imaging modalities may be regarded as complementary. Given the developing applications of DWI, the increasing use of multimodality imaging (8), and the expected advent of fully integrated PET/MRI systems (9), knowledge of the characteristics, possibilities, and limitations of DWI technique is becoming increasingly important. This is true for both the imaging specialists and the clinicians who use these modalities. This article will review the basic principles, clinical applications, and limitations of DWI. Furthermore, the available evidence that correlates and compares 18 F-FDG PET with DWI will be reviewed.

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Normal Brain and Brain Tumor: Multicomponent Apparent Diffusion Coefficient Line Scan Imaging

Cited by 142 publications

References 24 publications

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Squamous Cell Carcinoma of the Head and Neck: Comparison of Diffusion-weighted MRI at b-values of 1,000 and 2,000 s/mm<sup>2</sup> to Predict Response to Induction Chemotherapy

Complementary Roles of Whole-Body Diffusion-Weighted MRI and¹⁸F-FDG PET: The State of the Art and Potential Applications

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Normal Brain and Brain Tumor: Multicomponent Apparent Diffusion Coefficient Line Scan Imaging

Cited by 142 publications

References 24 publications

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Direct and fast detection of neuronal activation in the human brain with diffusion MRI

Squamous Cell Carcinoma of the Head and Neck: Comparison of Diffusion-weighted MRI at b-values of 1,000 and 2,000 s/mm<sup>2</sup> to Predict Response to Induction Chemotherapy

Complementary Roles of Whole-Body Diffusion-Weighted MRI and18F-FDG PET: The State of the Art and Potential Applications

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Product

Resources

About

Complementary Roles of Whole-Body Diffusion-Weighted MRI and¹⁸F-FDG PET: The State of the Art and Potential Applications