Detection of Brain Metastases Using Magnetic Resonance Imaging
In detecting brain metastases, three-dimensional (3D) magnetic resonance imaging (MRI), which exploits a T1-weighted contrast mechanism, has been widely used after administering T1-enhancing contrast agents. However, since contrast materials remain in both blood and the tumor parenchyma and increases the signal intensity of both regions, it is often challenging to differentiate brain tumors from blood. The purpose of this work is to develop a novel, highly selective whole-brain metastases MRI, wherein the signal intensity of the brain tumor is enhanced while that of blood is suppressed. A 3D non-CPMG fast/turbo spin echo pulse sequence, which incorporates variable refocusing-flip-angles and flow-sensitizing gradients, was employed to suppress blood signals. To avoid loss of signals in stationary tissues resulting from the non-CPMG condition, the first refocusing-flip-angle was forced to 180°. Simulations and in vivo volunteer and patient experiments were performed to demonstrate the effectiveness of this approach in detecting small brain metastases.
KeywordsMagnetic resonance imaging Brain metastases Black-blood Fast spin echo Contrast-enhanced
Numerical simulation in this manuscript follows closely a prior published paper by the authors 
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