Biological correlates of diffusivity in brain abscess

Mishra, Asht M.; Gupta, Rakesh K.; Saksena, Sona; Prasad, Kashi Nath; Pandey, Chandra M.; Rathore, Divya; Purwar, Ankur; Rathore, Ram K.S.; Husain, Nuzhat; Jha, Deepak Kumar; Jaggi, Ramandeep Singh; Husain, Mazhar

doi:10.1002/mrm.20645

Cited by 88 publications

(50 citation statements)

References 18 publications

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“…10,25 The absence of AAs in patients with aerobic and anaerobic culture-positive brain abscesses on in vivo 1 H-MR spectroscopy could be explained by the lower inflammatory cell count in the pus of these patients, resulting in a low concentration of metabolites, which was below the sensitivity of the 1.5T MR imaging. 26 On the basis of these data, it appears that the presence of AAs is a sensitive marker of pyogenic brain abscess; however, its absence does not rule it out.…”

Section: Discussionmentioning

confidence: 97%

In Vivo Proton MR Spectroscopy Evaluation of Pyogenic Brain Abscesses: A Report of 194 Cases

Pal¹,

Bhattacharyya²,

Husain³

et al. 2009

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE:The combination of nonspecific clinical findings and similarities in morphologic appearances on imaging often makes it difficult to distinguish abscesses from other brain lesions. We present a retrospective analysis of in vivo 1 H-MR spectroscopy data for characterization of the etiology of the brain abscess based on the established criteria and demonstrate the sensitivity and specificity of metabolite markers assigned to specific bacterial groups defined by the microbial culture in 194 patients.

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Section: Discussionmentioning

confidence: 97%

In Vivo Proton MR Spectroscopy Evaluation of Pyogenic Brain Abscesses: A Report of 194 Cases

Pal¹,

Bhattacharyya²,

Husain³

et al. 2009

AJNR Am J Neuroradiol

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“…In vitro measurements of ADC values in pus indicate that viable cell attenuation is the most important determinant of hindered diffusion in pus. 65 Hence, infectious etiologies for intracranially reduced diffusion include pyogenic abscess, 29,30 subdural or epidural empyema, 66 and intraventricular empyema. 67 Similarly, low ADC values due to hindered water motion also produce very bright signal intensity on DWI within extra-axial epidermoid masses 68,69 and within acute clotted hematomas, except in T2 dark hematomas due to T2 blackout.…”

Section: Adc Mapping Of Healthy Human Brain and Of Cerebral Pathologymentioning

confidence: 99%

Diffusion Tensor MR Imaging and Fiber Tractography: Theoretic Underpinnings

Mukherjee¹,

Berman²,

Chung³

et al. 2008

AJNR Am J Neuroradiol

430

312

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SUMMARY:In this article, the underlying theory of clinical diffusion MR imaging, including diffusion tensor imaging (DTI) and fiber tractography, is reviewed. First, a brief explanation of the basic physics of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping is provided. This is followed by an overview of the additional information that can be derived from the diffusion tensor, including diffusion anisotropy, color-encoded fiber orientation maps, and 3D fiber tractography. This article provides the requisite background for the second article in this 2-part review to appear next month, which covers the major technical factors that affect image quality in diffusion MR imaging, including the acquisition sequence, magnet field strength, gradient amplitude and slew rate, and multichannel radio-frequency coils and parallel imaging. The emphasis is on optimizing these factors for state-of-the-art DWI and DTI based on the best available evidence in the literature. Diffusion MR imaging of the brain was first adopted for use in clinical neuroradiology during the early 1990s and was found to have immediate utility for the evaluation of suspected acute ischemic stroke. Since that time, enormous strides forward in the technology of diffusion imaging have greatly improved image quality and enabled many new clinical applications. These include the diagnosis of intracranial pyogenic infections, masses, trauma, and vasogenic-versus-cytotoxic edema. Furthermore, the advent of diffusion tensor imaging (DTI) and fiber tractography has opened an entirely new noninvasive window on the white matter connectivity of the human brain. DTI and fiber tractography have already advanced the scientific understanding of many neurologic and psychiatric disorders and have been applied clinically for the presurgical mapping of eloquent white matter tracts before intracranial mass resections.This 2-part review explores the current state of the art for the acquisition and analysis of clinical diffusion imaging, including DTI and fiber tractography. This first article begins with an explanation of the basic physics and underlying theory of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping. This is followed by an overview of the additional information that can be derived from the diffusion tensor, including diffusion anisotropy, color-encoded fiber-orientation maps, and 3D fiber tractography. This article provides the necessary background for the second article, which focuses on the major technical factors that affect image quality in diffusion imaging, with an emphasis on optimizing these factors for state-of-the-art DWI and DTI based on the best available evidence in the literature. Theoretic Underpinnings of Diffusion ImagingBrownian Motion and Tissue Ultrastructure Diffusion, also known as "Brownian motion," refers to constant random microscopic molecular motion due to heat. At a fixed temperature, the rate of diffusion can be described by the Einstein equation 1 :where Ͻr 2 Ͼ refers...

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“…A number of studies have demonstrated that MT imaging is useful for characterizing different intracranial lesions and quantifying true disease load (16 -24,26). The contents of the cysts include intact inflammatory cells, proteinaceous material, necrotic debris, or a combination thereof in the form of viscosity of the fluid (12,27,28), and are known to influence the MT ratio (MTR) and FLAIR signal intensity (12,13). We prospectively performed MT and FLAIR imaging in 33 patients with intracranial cystic mass lesions to 1) compare the signal intensity on the FLAIR and MTR for delineating abscess from non-abscess, and 2) correlate these MR parameters with the viscosity, viable cell density, and total protein concentration of cystic fluid from patients with cystic lesions.…”

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Comparison of the magnetization transfer ratio and fluid‐attenuated inversion recovery imaging signal intensity in differentiation of various cystic intracranial mass lesions and its correlation with biological parameters

Mishra¹,

Reddy²,

Husain³

et al. 2006

Magnetic Resonance Imaging

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Purpose:To compare the signal intensity on the fluid attenuated inversion recovery (FLAIR) sequence and magnetization transfer ratios (MTRs) for the differentiation of abscesses from non-abscess cystic brain lesions, and to correlate these MR parameters with the viscosity, viable cell density and total protein concentration of the cystic fluid. Materials and Methods: Signal intensity on FLAIR andMTRs from the cystic cavity of lesions were calculated from 33 patients (brain abscess (N ϭ 12) and non-abscess (N ϭ 21)). The fluid from the lesion was aspirated at the time of surgery, and the viscosity, viable cell density, and total protein concentration were measured.Results: Signal intensity on FLAIR correlated significantly with the total protein concentration in abscess (r ϭ 0.60, P Ͻ 0.05) and non-abscess lesions (r ϭ 0.41, P Ͻ 0.05). However, there was no significant difference (P Ͼ 0.05) in the FLAIR signal intensity of the abscess (318.8 Ϯ 75) and non-abscess group (258 Ϯ 47). The MTR of the brain abscesses (13 Ϯ 0.95) was significantly higher (P Ͻ 0.05) than that of the non-abscess group (3.5 Ϯ 0.3). A significant correlation was observed between MTR and viscosity (r ϭ 0.75, P Ͻ 0.05), total protein concentration (r ϭ 0.60, P Ͻ 0.05), and cell density (r ϭ 0.70, P Ͻ 0.05) in brain abscess, and viscosity (r ϭ 0.81, P Ͻ 0.05) and total protein concentration (r ϭ 0.41, P Ͻ 0.05) in non-abscess lesions. Conclusion:It is possible to differentiate brain abscesses from non-abscess cystic lesions using MT imaging. The MTR correlates significantly with the viscosity, viable cell density, and total protein concentration in brain abscess, and with viscosity and total protein concentration in nonabscess lesions. FLAIR signal intensity correlates significantly only with the total protein concentration in abscess and non-abscess lesions.

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Biological correlates of diffusivity in brain abscess

Cited by 88 publications

References 18 publications

In Vivo Proton MR Spectroscopy Evaluation of Pyogenic Brain Abscesses: A Report of 194 Cases

In Vivo Proton MR Spectroscopy Evaluation of Pyogenic Brain Abscesses: A Report of 194 Cases

Diffusion Tensor MR Imaging and Fiber Tractography: Theoretic Underpinnings

Comparison of the magnetization transfer ratio and fluid‐attenuated inversion recovery imaging signal intensity in differentiation of various cystic intracranial mass lesions and its correlation with biological parameters

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