A year ago he had a blood clot removed from his brain.

他脑内的块一年前被取出了。

At highest field strengths, the core of the clot may have low signal on T2-weighted images, due to the presence of intracellular methemoglobin or of deoxyhemoglobin.

高场强时，块的中T2权像是低信号影，这是由于细胞内的高铁红蛋白或还原型红蛋白存产生的。