Optimized Flat-Detector CT in Stroke Imaging: Ready for First-Line Use?

Abstract

Background: Using flat-detector CT (FD-CT) for stroke imaging has the advantage that both diagnostic imaging and endovascular therapy can be performed directly within the Angio Suite without any patient transfer and time delay. Thus, stroke management could be speeded up significantly, and patient outcome might be improved. But as precondition for using FD-CT as primary imaging modality, a reliable exclusion of intracranial hemorrhage (ICH) has to be possible. This study aimed to investigate whether optimized native FD-CT, using a newly implemented reconstruction algorithm, may reliably detect ICH in stroke patients. Additionally, the potential to identify ischemic changes was evaluated. Methods: Cranial FD-CT scans were obtained in 102 patients presenting with acute ischemic stroke (n = 32), ICH (n = 45) or transient ischemic attack (n = 25). All scans were reconstructed with a newly implemented half-scan cone-beam algorithm. Two experienced neuroradiologists, unaware of clinical findings, evaluated independently the FD-CTs screening for hemorrhage or ischemic signs. The findings were correlated to CT, and rater and inter-rater agreement was assessed. Results: FD-CT demonstrated high sensitivity (95-100%) and specificity (100%) in detecting intracerebral and intraventricular hemorrhage (IVH). Overall, interobserver agreement (κ = 0.92) was almost perfect and rater agreement to CT highly significant (r = 0.81). One infratentorial ICH and 10 or 11 of 22 subarachnoid hemorrhages (SAHs) were missed of whom 7 were perimesencephalic. The sensitivity for detecting acute ischemic signs was poor in blinded readings (0 or 25%, respectively). Conclusions: Optimized FD-CT, using a newly implemented reconstruction algorithm, turned out as a reliable tool for detecting supratentorial ICH and IVH. However, detection of infratentorial ICH and perimesencephalic SAH is limited. The potential of FD-CT in detecting ischemic changes is poor in blinded readings. Thus, plain FD-CT seems insufficient as a standalone modality in acute stroke, but within a multimodal imaging approach primarily using the FD technology, native FD-CT seems capable to exclude reliably supratentorial hemorrhage. Currently, FD-CT imaging seems not yet ready for wide adoption, replacing regular CT, and should be reserved for selected patients. Furthermore, prospective evaluations are necessary to validate this approach in the clinical setting.

Direct transfer to angiosuite to reduce door-to-puncture time in thrombectomy for acute stroke

“…Our study showed that primary angiography in selected patients with a cone-bean CT scan14 15 in the angiosuite as the only selection criterion can dramatically reduce the mean D2P to <20 min. This spectacular reduction in workflow times was achieved at an acceptable cost: 25% of the patients transferred to the angiosuite did not finally benefit from EVT either because they had an intracranial hemorrhage or because no treatable occlusion was identified on the initial angiogram.…”

Interfacility Transfer Directly to the Neuroangiography Suite in Acute Ischemic Stroke Patients Undergoing Thrombectomy

“…Additionally, this approach may serve as a paradigm for direct transfer of patients with high suspicion for LVO directly from the field to the neuroangiography suite, particularly with improvements in the quality of CT technology within the neuroangiography suite in detecting hemorrhage and identifying early ischemic change. 25,26 …”

Diagnosing Early Ischemic Changes with the Latest-Generation Flat Detector CT: A Comparative Study with Multidetector CT

“…13 However, the pre-MT ASPECTS can be very important for the treating neurointerventionalist in patients with wake-up strokes or unknown clinical onset as well as in scenarios in which intervention is prolonged and termination of the MT has to be discussed after multiple thrombectomy maneuvers. There is growing evidence that FDCT can be reliably used to exclude intracerebral hemorrhage 9,14,15 and that the use of timeresolved flat detector CTA and flat detector CTP is feasible, showing sufficient reliability for decision-making. 16,17 One of the most recent studies addressing the reliability of FDCT in acute stroke by Eckert et al 15 also reported data on the reliability of detecting ischemic changes on FDCT.…”

“…There is growing evidence that FDCT can be reliably used to exclude intracerebral hemorrhage 9,14,15 and that the use of timeresolved flat detector CTA and flat detector CTP is feasible, showing sufficient reliability for decision-making. 16,17 One of the most recent studies addressing the reliability of FDCT in acute stroke by Eckert et al 15 also reported data on the reliability of detecting ischemic changes on FDCT. This study reported poor sensitivity for FDCT to detect early ischemic signs compared with post-MT MDCT.…”

“…However, the authors of this study evaluated FDCT images acquired with an older angiography system (Axiom Artis dBA; Siemens) and did not use ASPECTS as a systematic evaluation method to search for early ischemic changes, and only 4 (12.5%) of the 32 patients with ischemic stroke included in this study had early ischemic changes on the initial MDCT. 15 In contrast, we used a latest-generation angiography suite with 16-bit readout, which allows better contrast resolution compared with the older systems. Additionally, 20 (83.3%) of the 24 patients included in our study had early ischemic signs on initial MDCT (ASPECTS Ͻ 10), which renders our cohort more eligible for the comparison of ischemic signs detected on MDCT versus FDCT.…”