الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 92 |  |  |
| | | from | 92 | | |
Abstract
Despite the excellent soft tissue contrast provided by MRI, the sensitivity and specificity with which this modality differentiate between brain abscess in capsule stage and intra-cerebral cystic or necrotic tumor is limited.
Conventional contrast-enhanced MRI reveals ring enhancement of a brain abscess that is similar to the ring enhancement of a necrotic high-grade glioma or metastasis. The management of these disease entities is different and can potentially affect the clinical outcome
Advanced MRI techniques (DWI, MRS and DSC MR perfusion) may be used to differentiate between cerebral abscesses and high grade brain neoplasms and give important in vivo physiologic and metabolic information, complementing morphologic findings from conventional MRI in the clinical setting.
Diffusion weighted MRI imaging provides qualitative and quantitative information about the diffusion properties. It gives magnetic resonance imaging (MRI) studies a new level by supplementing the primarily anatomical information collected by the standard sequences with functional information.
Perfusion-weighted MRI provides non-invasive measurement of vascularity. Relative cerebral blood volume (rCBV) maps derived from perfusion-weighted MR images can be used to quantify areas of neovascularization. Perfusion MRI has become an important mean of characterizing intracranial neoplasms.
Magnetic Resonance Spectroscopy (MRS) is an analytical method used in chemistry that enables the identification and quantification of metabolites in samples. It differs from conventional Magnetic Resonance Imaging (MRI) in that spectra provide physiological and chemical information instead of anatomy.
H-MRSI in brain lesions is feasible, reasonable, and a valuable clinical tool especially when the conventional MR imaging and the clinical history are ambiguous.
With the appearance of MR spectroscopy, contrast enhanced perfusion and diffusion imaging, a step towards obtaining radiological base line data, nearly equivalent to the histopathological results.
This study aimed to assess the role of MR spectroscopy, MR perfusion and diffusion in evaluation and differentiation between brain abscesses in capsule stage and intra-cerebral necrotic or cystic tumor.
The study included 15 patients all the patients underwent conventional MR study and advanced neuro image package including MR spectroscopy, perfusion and diffusion examination. 5 lesions were histopathologically proven and matching with the diagnosis, the rest was confirmed by response to treatment, radiological and clinical follow up and laboratory investigations.
In the present study, we have noticed that most brain abscesses (6 cases) were hyperintense on diffusion weighted imaging with low ADC value denoting diffusion restriction with an ADC value from the center of the lesion in abscess group was ranging from 0. 3 to 1 x 10-3 mm2/second compared to neoplastic lesions of 1.6 to 2.9 mm2 x 10-3 mm2/second.