[TS2-1B-1] Neuroimaging: How to interpret Brain MRI
Brain MRI is widely used in clinical practice, and provides much information. In this lecture, I would show how to read/interpret neuropediatric MRI.
1. With myelination, T1- and T2-weighted images (WI) show T1 and T2 shortening (T1 high and T2 low signal); T1 shortening is usually prior to T2 shortening. It is useful to look at the splenium (Sp) and genu (Ge) of the corpus callosum for evaluation of myelination; T1 shortening in Sp after 4 months, T2 shortening in Sp and T1 shortening in Ge after 6 months, and T2 shortening in Ge after 8 months. Lack or insufficient myelination on MRI is a key finding in hypomyelinating disorders, including Pelizaeus-Merzbacher disease.
2. FLAIR image can detect cysts in abnormal white matter, both of which show high signal on T2WI (MLC, VWM); and meningeal lesions (Sturge-Weber syndrome, meningitis)
3. Because abnormal lesion usually shows T1 and T2 prolongation (T1 low and T2 high signal), it is important to know the lesions showing T1 and T2 shortening, including fat, hemorrhagic component, calcification. T2 star image or susceptibility weighted image enhance T2 shortening due to magnetic susceptibility effect.
4. Diffusion weighted image (DWI) measures the motion of water molecules in the tissue. DWI shows reduced diffusion (low ADC) in cytotoxic edema (acute arterial infarction) and intramyelinic edema (MAT I/III deficiency), and increased diffusion (high ADC) in vasogenic edema (PRES, venous infarction), demyelination/hypomyelination.
5. MR spectroscopy provides neurophysiological and neurochemical information in many disorders, including acute encephalopathy, metabolic disorders.
1. With myelination, T1- and T2-weighted images (WI) show T1 and T2 shortening (T1 high and T2 low signal); T1 shortening is usually prior to T2 shortening. It is useful to look at the splenium (Sp) and genu (Ge) of the corpus callosum for evaluation of myelination; T1 shortening in Sp after 4 months, T2 shortening in Sp and T1 shortening in Ge after 6 months, and T2 shortening in Ge after 8 months. Lack or insufficient myelination on MRI is a key finding in hypomyelinating disorders, including Pelizaeus-Merzbacher disease.
2. FLAIR image can detect cysts in abnormal white matter, both of which show high signal on T2WI (MLC, VWM); and meningeal lesions (Sturge-Weber syndrome, meningitis)
3. Because abnormal lesion usually shows T1 and T2 prolongation (T1 low and T2 high signal), it is important to know the lesions showing T1 and T2 shortening, including fat, hemorrhagic component, calcification. T2 star image or susceptibility weighted image enhance T2 shortening due to magnetic susceptibility effect.
4. Diffusion weighted image (DWI) measures the motion of water molecules in the tissue. DWI shows reduced diffusion (low ADC) in cytotoxic edema (acute arterial infarction) and intramyelinic edema (MAT I/III deficiency), and increased diffusion (high ADC) in vasogenic edema (PRES, venous infarction), demyelination/hypomyelination.
5. MR spectroscopy provides neurophysiological and neurochemical information in many disorders, including acute encephalopathy, metabolic disorders.