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Background
How DWI has been developed and what are the basic physical principles of obtaining diffusion signal. Compare monoexponential DWI, diffusion tensor imaging, diffusion spectral imaging, diffusion kurtosis imaging and intravoxel incoherent motion. What are the differences of each diffusion model? Challenges of acquiring, postprocessing and interpreting different diffusion models. Enumerate important metrics from each diffusion model. Advances of DWI on ultrahigh field 7 T. Challenges of DWI acquisition on 7 T. Various clinical applications in daily practice, for example; early detection of ischemic stroke, predicting outcomes in TBI, differentiating between brain abscess and rim-enhancing brain metastasis as well as presurgical mapping of brain tumors. How can diffusion be helpful in predicting tumor grade? How can diffusion help in the evaluation of CNS lymphoma?

Educational Goals / Teaching Points
Discuss the basic physics of DWI. Demonstrate different models of DWI. Compare pros and cons of each DWI model. Illustrate potential role of ultrahigh field 7 T in DWI acquisition. Discuss the clinical applications in daily practice.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Important clinical applications of DWI. Acute ischemic stroke (AIS), early detection of hyper-acute and acute ischemic strokes, brain tumors, grade primary brain tumors, differentiate primary from secondary brain tumors, monitor disease progression and evaluate treatment outcomes, differentiation infectiouss process and intracranial abscess from rim-enhancing tumors such as brain metastasis, biomarker of demyelinating diseases. Diffusion Tensor Imaging:important clinical applications, brain tumor and presurgical planning, monitor disease progression such as demyelinating diseases, traumatic brain injury and prediction of outcomes, neuropsychiatric and neurodegenerative disorders with evaluation of structural brain networks, prediction of prognosis in case of stroke. Non-gaussian and multi-compartment diffusion models: diffusion Kurtosis imaging (DKI), plausible clinical applications, neoplasm: differentiate high from low-grade glioma, neurodegenerative disease: marker for neuronal loss, demyelinating disease: evaluate myelin integrity. Intravoxel Incoherent Motion (IVIM): plausible clinical applications, differentiate high from low-grade gliomas, monitor antiangiogenic treatment, analysis for cerebral perfusion without the need for IV contrast. Ultra-high field 7 T and diffusion weighted imaging: potential values of UHF-7 T, increasing the spatial resolution, reducing the partial volume effect, the SNR of DTI dramatically surpass to the increase in magnetic field strength, better evaluation of anatomic connectivity since it allows for better separation of WM and GM fiber tracts. Challenges of diffusion acquisition on UHF-7 T: SAR, Lengthy scans.

Conclusion
This will be a brief educational material for the radiology trainee reviewing the different advanced DWI techniques and neuroimaging applications, including various clinical applications in daily practice.