Recent Administration of Iodinated Contrast Renders Core Infarct Estimation Inaccurate Using RAPID Software

Abstract

BACKGROUND AND PURPOSE: Automated CTP software is increasingly used for extended window emergent large-vessel occlusion to quantify core infarct. We aimed to assess whether RAPID software underestimates core infarct in patients with an extended window recently receiving IV iodinated contrast. MATERIALS AND METHODS: We reviewed a prospective, single-center data base of 271 consecutive patients who underwent CTA 6 CTP for acute ischemic stroke from May 2018 through January 2019. Patients with emergent large-vessel occlusion confirmed by CTA in the extended window (.6 hours since last known well) and CTP with RAPID postprocessing were included. Two blinded raters independently assessed CT ASPECTS on NCCT performed at the time of CTP. RAPID software used relative cerebral blood flow of ,30% as a surrogate for irreversible core infarct. Patients were dichotomized on the basis of receiving recent IV iodinated contrast (,8 hours before CTP) for a separate imaging study. RESULTS: The recent IV contrast and contrast-naïve cohorts comprised 23 and 15 patients, respectively. Multivariate linear regression analysis demonstrated that recent IV contrast administration was independently associated with a decrease in the RAPID core infarct estimate (proportional increase ¼ 0.34; 95% CI, 0.12-0.96; P ¼ .04). CONCLUSIONS: Patients who received IV iodinated contrast in proximity (,8 hours) to CTA/CTP as part of a separate imaging study had a much higher likelihood of core infarct underestimation with RAPID compared with contrast-naïve patients. Over-reliance on RAPID postprocessing for treatment disposition of patients with extended window emergent large-vessel occlusion should be avoided, particularly with recent IV contrast administration. ABBREVIATIONS: ELVO ¼ emergent large-vessel occlusion; LKW ¼ last known well; MT ¼ mechanical thrombectomy; PI ¼ proportional increases; rCBF ¼ relative cerebral blood flow Q uantifying core infarction versus viable ischemic penumbra is at the crux of patient selection for mechanical thrombectomy (MT) in the setting of anterior circulation emergent largevessel occlusion (ELVO). While patients with large infarcts tend to demonstrate worse clinical outcomes following reperfusion, successful recanalization of sizable ischemic penumbra, indicative of salvageable tissue, may result in drastic clinical improvement. 1

Angiography suite cone‐beam CT perfusion for selection of thrombectomy patients: A pilot study

“…Semiquantitative values, such as the ROI ratios used in this study, have been considered more reliable than the absolute ROI values because they can reduce variations related to the technique (time of acquisition after contrast injection, time of contrast clearance after MDCTP) or image processing among software 19 . Core underestimation may be seen in patients receiving IV contrast prior to CTP imaging 23 ; however, Dorn et al. showed that prior IV contrast administration did not influence on the CTP parameters 24 .…”

“…In this study, we demonstrated that the perfusion maps derived from The bias (blue line) and 95% confidence interval (red lines) are presented. CBCTP, cone-beam CT perfusion; CBF, cerebral blood flow; CBV, cerebral blood volume; MDCTP, multidetector CT perfusion; MTT, mean transit time; Tmax, time-to-maximum; TTP, time to peak contrast concentration imaging 23 ; however, Dorn et al showed that prior IV contrast administration did not influence on the CTP parameters. 24 Moreover, the contrast dose received in CBCTP after MDCTP was relatively low since in our stroke triage CTA imaging protocol is derived from MDCTP and no additional bolus is given for CTA acquisition.…”

Evaluation of time-resolved whole brain flat panel detector perfusion imaging using RAPID ANGIO in patients with acute stroke: comparison with CT perfusion imaging

“…Finally, all patients had recently received a bolus of intravenous contrast. One report has suggested that contemporaneous contrast administration may affect core estimation 30…”

Do Prior Iodine Contrast Injections Affect Cerebral Blood Flow Measurement on CT Perfusion Studies of Patients with Large-Vessel Occlusions?

“…Second, both core under-and overestimations are welldescribed limitations of CTP that are inherent to using perfusion as a surrogate of the core. 2 As shown in Fig 7, 1 the authors compared a delay-insensitive CTP processing method (RApid processing of PerfusIon and Diffusion [RAPID; iSchemaView]) with a delay-compensated (but not delay-insensitive) parametric CTP processing method (Advanced-Visualization Workstation; GE Healthcare). The apparent CBF reduction on the parametric deconvolution methods is not easily disambiguated from artifactual changes arising from delay-estimation and compensation errors between the arterial input function and the tissue.…”