A prospective, multicenter pilot study investigating the utility of flat detector derived parenchymal blood volume maps to estimate cerebral blood volume in stroke patients
- David Fiorella1,
- Aquilla Turk2,
- Imran Chaudry2,
- Raymond Turner2,
- Jared Dunkin1,
- Clemente Roque1,
- Marily Sarmiento3,
- Yu Deuerling-Zheng3,
- Christine M Denice1,
- Marlene Baumeister1,
- Adrian T Parker2,
- Henry H Woo1
- 1Department of Neurosurgery, Stony Brook University Medical Center, Stony Brook, New York, USA
- 2Medical University of South Carolina, Charleston, South Carolina, USA
- 3Seimens Medical Imaging, Erlangen, Germany
- Correspondence to Dr D Fiorella, Department of Neurological Surgery, Stony Brook University Medical Center, Cerebrovascular Center, Health Sciences Center T-12 080, Stony Brook, NY 11794-8122, USA;
- Received 25 May 2013
- Revised 11 July 2013
- Accepted 15 July 2013
- Published Online First 13 August 2013
Purpose Newer flat panel angiographic detector (FD) systems have the capability to generate parenchymal blood volume (PBV) maps. The ability to generate these maps in the angiographic suite has the potential to markedly expedite the triage and treatment of patients with acute ischemic stroke. The present study compares FP-PBV maps with cerebral blood volume (CBV) maps derived using standard dynamic CT perfusion (CTP) in a population of patients with stroke.
Methods 56 patients with cerebrovascular ischemic disease at two participating institutions prospectively underwent both standard dynamic CTP imaging followed by FD-PBV imaging (syngo Neuro PBV IR; Siemens, Erlangen, Germany) under a protocol approved by both institutional review boards. The feasibility of the FD system to generate PBV maps was assessed. The radiation doses for both studies were compared. The sensitivity and specificity of the PBV technique to detect (1) any blood volume deficit and (2) a blood volume deficit greater than one-third of a vascular territory, were defined using standard dynamic CTP CBV maps as the gold standard.
Results Of the 56 patients imaged, PBV maps were technically adequate in 42 (75%). The 14 inadequate studies were not interpretable secondary to patient motion/positioning (n=4), an injection issue (n=2), or another reason (n=8). The average dose for FD-PBV was 219 mGy (median 208) versus 204 mGy (median 201) for CT-CBV. On CT-CBV maps 26 of 42 had a CBV deficit (61.9%) and 15 (35.7%) had a deficit that accounted for greater than one-third of a vascular territory. FD-PBV maps were 100% sensitive and 81.3% specific to detect any CBV deficit and 100% sensitive and 62.9% specific to detect any CBV deficit of greater than one-third of a territory.
Conclusions PBV maps can be generated using FP systems. The average radiation dose is similar to a standard CTP examination. PBV maps have a high sensitivity for detecting CBV deficits defined by conventional CTP. PBV maps often overestimate the size of CBV deficits. We hypothesize that the FP protocol initiates PBV imaging prior to complete saturation of the blood volume in areas perfused via indirect pathways (ie, leptomeningeal collaterals), resulting in an overestimation of CBV deficits, particularly in the setting of large vessel occlusion.
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