Method for fat suppression in T1-weighted inversion recovery MRI
T1-weighted inversion recovery (IR) imaging is a common MRI technique used for creating a contrast between different types of tissues. This technique allows detecting pathophysiologies in different regions of the body, including the heart, brain, and vasculature. T1 is the rate of magnetization recovery in a tissue. Tissue with short T1 values appears bright on IR images while tissues with long T1 values appear dark. Fat tissue appears very bright due to its short T1 value and its abundance in most patients. This can lead to problems in image interpretation as it makes it difficult to differentiate tissues that have similarly short T1 values. For example, bright fat signal can obscure the presence of bright infarcted myocardium (dead heart tissue) or fat can be mistaken for an infarct. In arrythmogenic right ventricular dysplasia (ARVD), the discrimination between fat and equally bright scar tissue is even more important and is challenging to detect with current techniques. Even though fat suppression methods exist, when combined with T1-weighted IR they work poorly or not at all. Therefore a robust method to reliably suppress fat signal is of great need.
Duke researchers developed the technique that completely suppresses magnetization and associated MR signal from fat making it appear dark in T1-weighted IR images. Fat suppression is achieved by modifying the radio frequency (RF) pulse sequence to selectively restore and later invert the fat tissue magnetization and acquire the image-contrast relevant data when the T1 recovery curve crosses the zero-magnetization line. This technique can be used with or without the administration of a contrast agent and it completely nulls the fat signal. It requires no manual parameter adjusting and no post-processing – only a simple change to an existing RF pulse sequence. The invention has been prototyped and tested in a phantom and in cardiac patients on two cardiac MRI scanners showing excellent results. This invention is only available for non-exclusive licensing.
- Robustly nulls fat signal even in T1-weighted IR imaging
- Can be used in presence of MR contrast agent
- Can be used with any type of readout