Dynamic CTA-Derived Perfusion Maps Predict Final Infarct Volume: The Simple Perfusion Reconstruction Algorithm

Abstract

BACKGROUND AND PURPOSE: Infarct core volume measurement using CTP (CT perfusion) is a mainstay paradigm for stroke treatment decision-making. Yet, there are several downfalls with cine CTP technology that can be overcome by adopting the simple perfusion reconstruction algorithm (SPIRAL) derived from multiphase CTA. We compare SPIRAL with CTP parameters for the prediction of 24-hour infarction.MATERIALS AND METHODS: Seventy-two patients had admission NCCT, multiphase CTA, CTP, and 24-hour DWI. All patients had successful/quality reperfusion. Patient-level and cohort-level receiver operator characteristic curves were generated to determine accuracy. A 10-fold cross-validation was performed on the cohort-level data. Infarct core volume was compared for SPIRAL, CTPtime-to-maximum, and final DWI by Bland-Altman analysis.RESULTS: When we compared the accuracy in patients with early and late reperfusion for cortical GM and WM, there was no significant difference at the patient level (0.83 versus 0.84, respectively), cohort level (0.82 versus 0.81, respectively), or the cross-validation (0.77 versus 0.74, respectively). In the patient-level receiver operating characteristic analysis, the SPIRAL map had a slightly higher, though nonsignificant (P , .05), average receiver operating characteristic area under the curve (cortical GM/WM, r ¼ 0.82; basal ganglia ¼ 0.79, respectively) than both the CTP-time-to-maximum (cortical GM/WM ¼ 0.82; basal ganglia ¼ 0.78, respectively) and CTP-CBF (cortical GM/WM ¼ 0.74; basal ganglia ¼ 0.78, respectively) parameter maps. The same relationship was observed at the cohort level. The Bland-Altman plot limits of agreement for SPIRAL and time-to-maximum infarct volume were similar compared with 24-hour DWI. CONCLUSIONS:We have shown that perfusion maps generated from a temporally sampled helical CTA are an accurate surrogate for infarct core. ABBREVIATIONS: AUC ¼ area under the curve; EVT ¼ endovascular therapy; mCTA ¼ multiphase CTA; ROC ¼ receiver operating characteristic; SPIRAL ¼ simple perfusion reconstruction algorithm; Tmax ¼ time-to-maximum E ndovascular therapy (EVT) for acute ischemic stroke can lead to remarkable results for improving stroke outcome. [1][2][3] The emphasis on fast treatment decisions for patients with acute ischemic stroke requires simple, quick, and accurate neuroimaging of patients for detection of early ischemic changes. Additionally, image-processing software that can provide this information should be preferably inexpensive and easily accessible to all stroke centers, both primary and comprehensive, around the world. CT is the most commonly used and practical imaging technique for assessing patients with acute stroke, but sensitivity and reliability are only modest, even in the hands of stroke specialists. Software systems, including perfusion analysis, to identify ischemic tissue using advanced imaging paradigms are now recommended by the American Stroke Association and have been used successfully in several clinical trials, including selection of patients fo...

Acute reperfusion therapies for acute ischemic stroke patients with unknown time of symptom onset or in extended time windows: an individualized approach

“…Baseline multiphase CTA images may also be processed through a simple perfusion reconstruction algorithm (SPIRAL) to produce perfusion maps that have good agreement with a commercially available deconvolution software (CT Perfusion 4D; GE Healthcare). 152 If these preliminary findings are confirmed by subsequent studies, standardized SPIRAL automation may prove equivalent with CTP, saving time, radiation, contrast injection and, eventually, financial resources. One-stop management of AIS patients in the angiosuite is an exciting recent development that integrates advances in penumbral 153 and collateral 154 neuroimaging with the use of flat-panel detector CT and is currently being tested in AIS patients.…”

Acute stroke imaging selection for mechanical thrombectomy in the extended time window: is it time to go back to basics? A review of current evidence

“…Dynamic CTA–perfusion is a novel CTA-based diagnostic tool obtaining perfusion parameters similarly to CTP by harnessing spatial and temporal information of a time-resolved three phase CTA 7 46…”

“…Assessment of hypoattenuation by ASPECTS outperformed non-contrast CT-ASPECTS and regional leptomeningeal collaterals (mCTA-rLMC) in predicting follow-up infarction 46. Based on this method, dCTA–perfusion derives perfusion parameters from time-attenuation curves and generates colour-coded perfusion maps similar to commercially available CTP maps to provide estimates of infarct core and penumbra 7. In a proof-of-concept study using the Simple Perfusion Reconstruction Algorithm , dCTA–perfusion infarct core volumes were comparable to those from CTP and correlated well to 24-hour DWI follow-up for cortical grey/white matter 7.…”

“…Last, novel imaging techniques are emerging that combine the usability of perfusion maps with the simplicity of basic imaging. Dynamic CTA–perfusion allows for the generation of perfusion maps based on the acquisition of a three phase time-resolved CTA (trCTA) 7. This may provide a more comprehensive imaging profile beyond non-contrast CT whenever CTP is not available.…”

How to Improve the Management of Acute Ischemic Stroke by Modern Technologies, Artificial Intelligence, and New Treatment Methods

“…Perfusion maps generated from a temporally sampled helical CTA are another option for infarct core imaging [67][68][69], and color-coded mCTA summation maps may facilitate the easier assessment of acute stroke pathology, including better assessment of collateral status, distal occlusions, carotid pseudo-occlusions, intracranial stenosis, and thrombus permeability [70]. ColorViz may be particularly useful for less experienced readers [71].…”