Mri brain sequences

This presentation contains very basic information regarding common MRI sequences of BRAIN MRI. This will be helpful for neurologist, medical students and graduates.

1. MRI Brain Sequences Dr. MD SHAH JALALUR RAHMAN SHAHI Junior Consultant, Oncology Ahsania Mission Cancer & General Hospital

2. Basic Mechanism of MRI Machine Each pulse sequence of MRI comprises of Radiofrequence sequence and Acquisition of that result. First step: MRI machine delivers energy which will excite proton spin and align Hydrogen atom by the strong Magnet of the machine Second step: Turn off the magnet. Third step: Observe as the atom realign due to entropy.

3. Common MRI Sequences for MRI Brain T1 T2 Flair DWI GRE MRS (this is not a sequence, rather an addition to the original MRI)

4. T1 weighted MRI Scans In T1 weighted MRI Scans Fat is bright Water is dark ( means CSF is dark) New blood is bright White matter is white as white matter contains lot of fat. Gray matter is gray or blackish What is it good for: Vascular changes Disruption of BBB Anatomic detail (Not as good as T2)

5. T2 weighted MRI Scans In T2 weighted MRI scan of Brain Mostly Fat is dark Water is bright like inflammation or CSF. (Cannot differentiate between CSF and inflammation due to Brain tumour or metastasis) Blood flow is dark (Blood vessel like cerebral vessels) T2 weighted MRI scans are useful for 1. To find out anatomic detail ( Even better than T1) 2. Better to find out most lesions (Although lesions encroaching CSF is difficult to delineate)

6. FLAIR: Fluid Attenuation Inversion Recovery FLAIR sequence is basically a T2 sequence in which free flowing fluid (CSF) is dark. Non free flowing water is bright like inflamed brains lesion or brain tumour with inflammation. FLAIR is useful for: Delineation of lesions near ventricles Other same as T2 Edema Gray-White differentiation.

7. T1 vs. T2 vs. FLAIR

8. MRS An analytical system in chemistry that helps in identification and quantification of metabolite in sample. MRS spectra provides physiological and chemical information instead of anatomy. When MRI + MRS are at the same time, Anatomical, chemical information can be gathered increasing precision.

9. THANK YOU