This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Magnetic Resonance Imaging, Subject name: Radiology
Which MRI sequence is used to detect brain edema? 
Select and explain. 
A. T1WI, B. FLAIR, C. SWI, D. DWI
B: FLAIR
Answer: B: FLAIR 
Explanation: FLAIR stands for Fluid Attenuation Inversion Recovery Sequence This sequence is similar to T2 with suppression of CSF/Fluid signal so the Brain Edema can be seen better. Figure: FLAIR image showing edema in bilateral occipital lobe in a case of PRES(posterior reversible encephalopathy syndrome).