Response to letter to the editor. "CT angiography source-images and CT perfusion: are they complementary tools for ischemic stroke evaluation?".

Cerebral blood volume (CBV) can be measured using a C-arm flat detector angiographic system. The present report describes a case in which cerebral hyperperfusion was detected with the Neuro parenchymal blood volume (PBV) system (syngo Neuro PBV IR, Siemens Medical Solutions, Erlangen, Germany) during carotid artery stenting (CAS). An 89-year-old man was referred to our hospital for cerebral brain infarction and severe stenosis of the left carotid artery. CAS was performed, and Neuro PBV was used to measure CBV both during and after the procedure. Postoperative Neuro PBV revealed dramatically increased CBV, and a hyperperfusion state was suspected. The next day, subarachnoid hemorrhage along the sulcus of the left hemisphere was revealed on computed tomography. Strict management of blood pressure was instituted just after the detection of hyperperfusion, and the patient was ultimately discharged from the hospital without any new neurological deficits. Neuro PBV has the advantage that it can be performed in the angiography suite and does not require patient transfer to an alternate setting. Therefore, intracranial hemodynamic changes can be detected during the procedure. We conclude that the Neuro PBV system is useful for monitoring intracranial hemodynamics during endovascular procedures.