Angiographic CT with intravenous administration of contrast medium is a noninvasive option for follow-up after intracranial stenting

Intracranial angioplasty and stenting (ICAS) is a therapeutic option in symptomatic intracranial atherosclerotic disease. Adequate follow-up examination is necessary to exclude in-stent restenosis. Conventional intraarterial digital subtraction angiography (ia-DSA) is the current gold standard, but it is an invasive technique and carries the risk of neurological complications. Angiographic CT (ACT) is a new technique that provides a volume dataset of the highest spatial resolution and high contrast resolution derived from a rotational acquisition of a c-arm-mounted flat-panel detector. The feasibility of ACT with intravenous administration of contrast medium (iv-ACT) for follow-up after ICAS is demonstrated. In two patients iv-ACT was performed as a follow-up examination 12 months after ICAS. High-resolution volume data from the rotational acquisitions were processed to provide delineation of the stent lumen as well as imaging of the brain parenchyma and vessels. In both patients the patency of the stent lumen was assessed successfully. In addition, all other brain vessels were displayed in a manner similar to their appearance on CT angiograms. The brain parenchyma was also adequately imaged in a manner similar to its appearance on CT images. We demonstrated the feasibility and diagnostic value of iv-ACT for follow-up imaging after ICAS. This new application has the potential to become the imaging method of choice after ICAS since it not only enables visualization of the patency of the stent lumen but also is minimally invasive and provides additional information about all brain arteries and the brain parenchyma.