Lung perfusion changes in COVID-19 pneumonia: a dual energy computerized tomography study

Objective: There is limited and contradictory information about pulmonary perfusion changes detected with dual energy computed tomography (DECT) in COVID-19 cases. The purpose of this study was to define lung perfusion changes in COVID-19 cases with DECT, as well as to reveal any possible links between perfusion changes and laboratory findings. Methods: Patients who had a positive RT-PCR for SARS-CoV-2 and a contrast-enhanced chest DECT examination were included in the study. The pattern and severity of perfusion deficits were evaluated, as well as the relationships between perfusion deficit severity and laboratory results and CT severity ratings. The paired t-test, Wilcoxon test, and Student’s t-test were used to examine the changes in variables and perfusion deficits. p < 0.05 was regarded as statistically significant. Results: Study population consisted of 40 patients. Mean age was 60.73 ± 14.73 years. All of the patients had perfusion deficits at DECT images. Mean perfusion deficit severity score of the population was 8.45 ± 4.66 (min.-max, 1–19). In 24 patients (60%), perfusion deficits and parenchymal lesions matched completely. In 15 patients (37.5%), there was partial match. D dimer, CRP levels, CT severity score, and perfusion deficit severity score all had a positive correlation Conclusions: Perfusion deficits are seen not only in opacification areas but also in parenchyma of normal appearance. The CT severity score, CRP, D-dimer, and SpO2 levels of the patients were determined to be related with perfusion deficit severity. Advances in knowledge: Findings of the current study may confirm the presence of micro-thrombosis in COVID-19 pneumonia.

Abstract 32: Residual Perfusion Deficit is Common Post Successful EVT and is Associated With Worse Clinical Outcome

Introduction: A significant portion of patients despite achieving successful recanalization following endovascular therapy (EVT) still have some residual perfusion deficit. The objective of this study was to identify the association of residual perfusion deficit with recanalization status and clot presence post EVT. Methods: Patients were included if they were evaluated at one of two comprehensive stroke centers from January 2015 through February 2018, had LVO of the anterior circulation, had baseline MRI pre EVT, and treated with EVT. Independent image reads by two separate readers blinded to target vessel, TICI score, and clinical outcome, evaluated the pre EVT, 2 hours, and 24 hours post EVT MRI for perfusion deficit and clot presence. The MTT and TTP maps post EVT were read separately for residual perfusion deficit, compared to the pre EVT perfusion deficit. Clot presence was read as susceptibility sign on GRE consistent with the vascular territory identified on the pre EVT PWI. Successful recanalization was defined as TICI 2b\3 in the IR suite. Early neurological improvement (ENI) was defined as a reduction of the admit NIHSS by ≥4 points or a score of 0-1 at 24 hours. Results: Fifty-eight patients were included with median age of 58 years, 55% female, 47% Black\African-American, median admit NIHSS of 19, 72% with M1 LVO, 69% treated with IV tPA, 79% achieved TICI of 2b\3, and 52% with ENI at 24 hours. All patients had a perfusion deficit pre EVT with 73% having a corresponding clot on GRE. Following EVT, 76% and 52% of patients had residual perfusion deficit at 2 and 24 hours post EVT, but only 24% and 13%, respectively, still had evidence of clot. For the 46 patients with successful recanalization, 41% still had some residual perfusion deficit at 24 hours, but only 9% still had clot, suggesting inadequate perfusion without a mechanical obstruction. The frequency of ENI at 24 hours was associated with complete reperfusion, 88% versus 46% (p=0.039) at 2 hours post EVT, and 76% versus 33% (p=0.002) at 24 hours post EVT. Conclusions: Residual perfusion deficit on post EVT MRI is common, even with successful recanalization, and is associated with poor outcome. Patients with residual perfusion deficit may benefit from early adjunctive therapy following EVT to improve outcome.

What Is the “Optimal” Target Mismatch Criteria for Acute Ischemic Stroke?

We aimed to compare Perfusion Imaging Mismatch (PIM) and Clinical Core Mismatch (CCM) criteria in ischemic stroke patients to identify the effect of these criteria on selected patient population characteristics and clinical outcomes. Patients from the INternational Stroke Perfusion Imaging REgistry (INSPIRE) who received reperfusion therapy, had pre-treatment multimodal CT, 24-h imaging, and 3 month outcomes were analyzed. Patients were divided into 3 cohorts: endovascular thrombectomy (EVT), intravenous thrombolysis alone with large vessel occlusion (IVT-LVO), and intravenous thrombolysis alone without LVO (IVT-nonLVO). Patients were classified using 6 separate mismatch criteria: PIM-using 3 different measures to define the perfusion deficit (Delay Time, Tmax, or Mean Transit Time); or CCM-mismatch between age-adjusted National Institutes of Health Stroke Scale and CT Perfusion core, defined as relative cerebral blood flow &lt;30% within the perfusion deficit defined in three ways (as above). We assessed the eligibility rate for each mismatch criterion and its ability to identify patients likely to respond to treatment. There were 994 patients eligible for this study. PIM with delay time (PIM-DT) had the highest inclusion rate for both EVT (82.7%) and IVT-LVO (79.5%) cohorts. In PIM positive patients who received EVT, recanalization was strongly associated with achieving an excellent outcome at 90-days (e.g., PIM-DT: mRS 0-1, adjusted OR 4.27, P = 0.005), whereas there was no such association between reperfusion and an excellent outcome with any of the CCM criteria (all p &gt; 0.05). Notably, in IVT-LVO cohort, 58.2% of the PIM-DT positive patients achieved an excellent outcome compared with 31.0% in non-mismatch patients following successful recanalization (P = 0.006).Conclusion: PIM-DT was the optimal mismatch criterion in large vessel occlusion patients, combining a high eligibility rate with better clinical response to reperfusion. No mismatch criterion was useful to identify patients who are most likely response to reperfusion in non-large vessel occlusion patients.

Abstract 129: Endovascular Thrombectomy Potential Benefits in Isolated M2 Occlusions Are Related to Stroke Severity and Penumbral Mismatch Deficit: A Secondary Analysis From the SELECT Study

Background: The efficacy of endovascular thrombectomy (EVT) in M2 occlusions is uncertain. Methods: In a prospective multicenter cohort study of imaging selection (SELECT), EVT outcomes were compared to medical managment (MM) in M2 occlusions. Further, we assessed for potential treatment benefit in patients with higher stroke severity (NIHSS) and a larger perfusion deficit on CTP (Tmax > 6 sec - ischemic core volume)The primary outcome was excellent outcome (mRS 0-1). Results: of 361 patients enrolled in SELECT, 87 had isolated M2 occlusion (EVT 59, MM 28). Baseline NIHSS median (IQR) (EVT 14 (10-20), MM 15 (9.5-19.5), p=0.72) and infarct volume rCBF<30% (EVT 7 (0-21) vs MM 18.5 (0-41.25), P=0.10). EVT was associated with higher rates of excellent outcomes (53% vs 21%, aOR:6.94, 95% CI=1.86-25.90, p=0.004) with a shift towards better mRS outcomes (adj cOR: 3.49, 95% CI=1.39-8.80, p=0.008), smaller final infarct volume (15.9 (2.7-48.0) vs 58 (24.3-141.9), P<0.001), and a reduction of neurological worsening (3% vs 22%, p=0.011), sICH (2% vs 21%, p=0.004), and mortality (5% vs 25%, p=0.011). Assessing outcomes in NIHSS strata; there was no significant increase in excellent outcomes rates in NIHSS ≤10 (EVT 65% vs MM 50%, aOR=1.59, 95% CI=0.21-12.01, p=0.65). In contrast, patients with NIHSS>10 had better outcomes with EVT (46%) vs MM (10%), aOR=11.39, 95% CI=1.80-72.11, p=0.01 as shown in figure 1. As perfusion deficit lesion size increased, the odds of achieving excellent outcomes was reduced (for each 10cc by 11%, aOR: 0.89, 95% CI=0.79-1.00, p=0.05). Excellent outcomes declined in patients with MM as perfusion deficit lesion size increased, yet in the EVT they were maintained as shown in figure 2. Similar results were obtained for mRS 0-2. Conclusion: EVT may result in better rates of excellent outcomes in isolated M2 occlusions, especially those with more severe strokes and larger perfusion deficits who are more likely to have worse outcomes without emergent reperfusion.

1177 The additive prognostic value of end-systolic pressure-volume relation by CMR in patients with with known or suspected coronary artery disease

Background The variation between rest and peak stress end-systolic pressure-volume relation is an afterload-independent index of left ventricular contractility. This index is easily obtained during routine stress echocardiography but can be derived also during a stress cardiovascular magnetic resonance (CMR) exam, that is the gold standard for the quantification of biventricular volumes. Purpose The aim of this study was to assess for the first time the prognostic value ofdelta rest-stress ESPVR (DESPVR) by dipyridamole stress-CMR in patients with known or suspected coronary artery disease (CAD). Methods One hundred and sixty-six consecutive patients (37 females, main age 61.96 ± 10.05 years) who underwent dipyridamole stress-CMR in a high volume CMR Laboratory were considered. Abnormal wall motion and perfusion at rest and after dipyridamole were analysed. Macroscopic myocardial fibrosis was detected by the late gadolinium enhancement (LGE) technique. The ESPVR was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson method. Results An abnormal stress CMR was found in 39 (23.5%) patients; 24 patients had a reversible stress perfusion defect in at least one myocardial segment and 15 a reversible stress perfusion defect plus worsening of stress wall motion in comparison with rest. Myocardial fibrosis was detected in 69 patients (41.6%). A DESPVR &lt; 0.009 was detected in 74 patients (44.6%). During a median follow up of 55.51 months (IQ range 33.20 months), 54 patients (32.5%) experienced major cardiac events: 5 deaths, 2 ventricular arrhythmias, 18 coronary syndromes, and 29 heart failure hospitalization.Reversible perfusion deficit, DESPVR &lt; 0.009, diabetes and family history were significant univariate prognosticators. In the multivariate analysisthe independent predictive factors were reversible perfusion deficit (hazard ratio-HR = 2.17, P = 0.010), DESPVR &lt; 0.009 (HR = 1.92, P = 0.028) and diabetes (HR = 2.42, P = 0.004). The Kaplan–Meier curve for DESPVR is shown in Figure 1. The log-rank test revealed a significant difference (P = 0.003). Conclusions DESPRV assessed by CMR provides a prognostic stratification in patients with known or suspected coronary artery disease, in addition to that supplied by reversible perfusion deficit and diabetes. Abstract 1177 Figure 1