1.5 Tesla Non-ultrashort but Short Echo Time Magnetic Resonance Angiography Describes the Arteries Near a Clipped Cerebral Aneurysm

Cerebral aneurysm and mother artery assessment after clipping is essential to evaluate aneurysm remnant, regrowth, and clip slippage. Usually, cerebral angiography and contrast-enhanced computed tomography angiography (CTA) are used for the evaluation, but they have the side effect of contrast medium and are time-consuming. Time-of-flight magnetic resonance angiography (TOF-MRA) is a non-invasive and fast modality, but clip-induced artifacts limit the signal near the metal clip. Recent ultrashort echo time (UTE)-MRA reduces metal artifacts but its availability is still low worldwide. Therefore, we developed a modified TOF-MRA sequence, named short TE-MRA, using Optima MR 360 1.5T Advance (GE Healthcare Life Sciences, Buckinghamshire, UK). It could describe the artery near the clip using general MRA equipment without recent UTE-MRA technology. We present a subarachnoid hemorrhage patient who underwent short TE-MRA about a year after clipping for the aneurysms at the bilateral internal carotid arteries. Short TE-MRA described the left internal carotid, middle cerebral, and anterior cerebral arteries. The right middle and anterior cerebral arteries were described, but the right internal carotid artery was not. Normal TOF-MRA could not describe them. Without recent UTE-MRA technology, short TE-MRA might be an alternative method for evaluating the artery near the clip. Short TE-MRA can be performed by general MRA equipment with a little time, so it may be helpful until UTE-MRA is widely used. Further research is needed on whether short TE-MRA can describe the aneurysm remnant, regrowth, and clip slippage up to the clinically useful level.