Introduction: Diffusion of water molecules is a passive process in which the water molecules move from the region of higher concentration towards the lower one. All diffusion weighted pulse sequences are based on fast planar imaging with the addition of bipolar gradient. Basic diffusion weighted imaging is used for detection and categorization of various brain lesions and stroke. Intravoxel incoherent motion uses an additional perfusion component which is based on signal calculation of water molecules in blood when it passes through the capillary web. Diffusion tensor imaging is based on understanding anisotropic movement of water, while diffusion kurtosis imaging also incorporates deviation from the Gaussian diffusion model. Therefore, diffusion tensor imaging and diffusion kurtosis imaging are more efficient in understanding the complex process of water diffusion in brain matter. Purpose: The purpose of diploma work is to systematically overview the literature, determine the advantages and disadvantages of each diffusion model and the most appropriate one for diagnosing a certain neurological condition. Methods: In diploma work we used a descriptive method and systematic analysis of numerous scientific articles. In our systematic review we included the articles that matched our inclusion criteria: articles written in the last decade about diffusion models and the pathology of adult brain. We acquired literature from Slovene and foreign bibliographic databases from 15. 10. 2019 to 15. 3. 2020. Results: We have included 25 articles in our overview and organised them in two separate tables. The first one contains information about the type of the study, diffusion model, number of participants, neurological pathology and b value used in the study. In the second table are brief key findings of an individual article. Discussion and conclusion: Based on our review we have established that diffusion weighted imaging and intravoxel incoherent motion are useful in diagnosing acute brain ischemia, brain tumour grading and categorization, while their disadvantage is poor image quality. Diffusion kurtosis imaging is in acquiring microstructural information of the whole brain better than diffusion tensor imaging. The latter is more established in practice. We believe that we have successfully presented advantages and disadvantages of each diffusion model and their clinical use.
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