What is T1 and T2 in CT?
T1-weighted images are produced by using short TE and TR times. The contrast and brightness of the image are predominately determined by T1 properties of tissue. Conversely, T2-weighted images are produced by using longer TE and TR times.
How can you tell the difference between a T1 and T2 MRI?
The best way to tell the two apart is to look at the grey-white matter. T1 sequences will have grey matter being darker than white matter. T2 weighted sequences, whether fluid attenuated or not, will have white matter being darker than grey matter. Read more about FLAIR sequence.
What’s bright on T1 MRI?
The list of entities associated with a high signal intensity on T1-weighted images is extensive and classically includes fat, proteins, hemorrhage, melanin and gadolinium.
Does contrast MRI show nerve damage?
Spine- Contrast MRI is sensitive to changes in cartilage and bone structure, making it easier to detect herniated discs, pinched nerves, spinal tumors, spinal cord compression, and fractures.
Why is fluid dark on T1?
Fat quickly realigns its longitudinal magnetization with B0, and it therefore appears bright on a T1 weighted image. Conversely, water has much slower longitudinal magnetization realignment after an RF pulse and therefore, has less transverse magnetization after an RF pulse. Thus, water has low signal and appears dark.
What are T1 and T2 lesions?
Specifically, T1 and T2 refers to the time taken between magnetic pulses and the image is taken. These different methods are used to detect different structures or chemicals in the central nervous system. T1 and T2 lesions refers to whether the lesions were detected using either the T1 or T2 method.
What does high T1 signal mean?
On T1-weighted images substances with longitudinal relaxation time, e.g. water demonstrate low signal (are hypointense), while substances with short longitudinal relaxation time (e.g. fat) display high signal (are hyperintense) [1].
How does T1 change with field strength?
For most biological tissues, empirical measurements suggest that T1 increases approximately as Bo1/3. Therefore, measured T1 values of most tissues will approximately double as field strength is raised from 0.3 T to 3.0 T and will increase by about 25% between 1.5T to 3.0T.