Korelacija mape difuznog keficijenta i difuzije sa stepenom maligniteta glijalnih tumora
Committee membersStojanović, Nebojša
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First application of magnetic resonance imaging (MRI) in the early 1980s radically changed the radiographic diagnosis of primary and secondary brain tumors. MRI is a key modality not only for lesion diagnosis, but also to evaluate the extension, type and grade of the tumor. Advanced MRI techniques such as diffusion weighted imaging (DWI) provide physiologic information that complements the anatomic information available with conventional MRI. The utility of DWI and apparent diffusion coefficients (ADC) mapping is in the preoperative diagnosis of brain tumors with respect to assessing cellularity or grade; distinguishing enhancing from non-enhancing areas, tumor from perifocal vasogenic edema, or viable tumor from necrosis; or predicting tumor response to treatment. Study results qualify ADC coefficient as an important quantitative marker of glioma as evidenced by the fact that the value of ADC is inversely proportional to the degree of the tumor cellularity and tumor grade. The high va...lues of ADC correspond to low grade gliomas, necrosis, cysts, while on the other hand, small values of ADC depict density, high cellularity and high grade malignant changes. The ADC has been found to have an inverse relation with the WHO grade of astrocytomas. Lower ADC values suggest a malignant high-grade gliomas, whereas higher ADCs suggest low-grade gliomas. The paper stresses that ADC is of great importance in clinical practice, in tumor behavior monitoring, in precious view of tumor response to standardized protocols, then this radiological ratio also has a valuable prognostic significance after surgical treatment and postoperative radiotherapy because there is a connection between the ADC values and survival time in patients with glioblastoma. The ADC values can be considered as predictive biomarker for the anti-angiogenesis treatment of malignant gliomas. ADC values show variation (increase) within vasogenic edema which monitors high and low grade gliomas, metastatic tumors, as a consequence of increased extracellular fluid. The values of ADC of high grades gliomas were significantly lower than the vales of ADC of metastases. To summarize, DWI can be complementary but very reliable imaging method not only for the diagnosis and surgical treatment of glioma grade, but also for successful monitoring of tumor recurrence and tumor response to treatment.