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العنوان
Role of Diffusion MRI in Differentiation
between the Common Pediatric Posterior
Fossa Brain Tumors/
المؤلف
Khattab, Osama Mohamed Abo-Bakr.
هيئة الاعداد
باحث / Osama Mohamed Abo-Bakr Khattab
مشرف / Hanaa Abdelkader Ahmed
مشرف / Eman Ahmed Fouad Darwish
تاريخ النشر
2018.
عدد الصفحات
172 p. :
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
الأشعة والطب النووي والتصوير
تاريخ الإجازة
1/1/2018
مكان الإجازة
جامعة عين شمس - كلية الطب - الأشعــة التشخيصيـــة
الفهرس
Only 14 pages are availabe for public view

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from 172

Abstract

B
rain tumors are the most prevalent solid tumors in children. In children older than 1 year of age, most tumors are located within the posterior fossa. Pilocytic astrocytomas (PAs), medulloblastomas (MBs), and ependymomas are the most common pediatric posterior fossa tumors, high-grade gliomas, atypical teratoid/rhabdoid tumor (ATRT), and choroid plexus papilloma (CPP) of the fourth ventricle are less frequent.
Although MR imaging is essential for diagnosis and evaluation of brain tumors, it offers limited information regarding tumor type and grade and is frequently far from being a definite diagnostic test, which is a role reserved for histology. Accurate preoperative diagnosis is an important goal in pediatric patients with posterior fossa neoplasm, because the different tumors dictate the need for different surgical approaches and have significantly different natural histories and outcomes.
Advanced MRI techniques have shown to provide important additional information about the biological, physiological, and metabolic features of brain tumors. Recent studies suggested that diffusion weighted imaging (DWI) may effectively distinguish between various posterior fossa tumor types and histological grades.
Results of this study shows that assessment of ADC values in enhancing, non necrotic, non edematous, solid parts of the main posterior fossa tumors enables correct differentiation between high and low grade tumors presurgically and between PAs, ependymomas, and medulloblastomas. Careful positioning of the ROIs within the enhancing, non necrotic, non-edematous, contrast enhancing tumor component appears to be essential in achieving accurate results. Nevertheless, due to intrinsic features of tumor pathology, overlap in ADC values was present between DIPGs and the other tumors and between MBs and ATRTs and thus cannot be used to reliably differentiate between these entities should the need arise.
To conclude, quantitative evaluation of DW- MRI findings with generation of ADC values and ratios is a simple and readily available technique for the accurate evaluation and diagnosis of the majority of pediatric posterior fossa neoplasm. Solely relying on qualitative evaluation of DW images and ADC maps in differentiation of tumors of the posterior fossa may give rise to false results. Conventional MRI findings remain indispensable and results of diffusion weighted imaging should always be interpreted in conjunction with conventional MRI features. This is especially true of DIPGs where DWI plays a limited role in diagnosis of these tumors.