Background and Purpose: Ischemic brain edema can be measured in computed tomography (CT) using quantitative net water uptake (NWU), a recently established imaging biomarker. NWU determined in follow-up CT after mechanical thrombectomy (MT) has shown to be a strong predictor of functional outcome. However, disruption of the blood–brain barrier after MT may also lead to contrast staining, increasing the density on CT scans, and hence, directly impairing measurements of NWU. The purpose of this study was to determine whether dual-energy dual-layer CT (DDCT) after MT can improve the quantification of NWU by measuring NWU in conventional polychromatic CT images (CP-I) and virtual non-contrast images (VNC-I). We hypothesized that VNC-based NWU (vNWU) differs from NWU in conventional CT (cNWU).Methods: Ten patients with middle cerebral artery occlusion who received a DDCT follow-up scan after MT were included. NWU was quantified in conventional and VNC images as previously published and was compared using paired sample t-tests.Results: The mean cNWU was 3.3% (95%CI: 0–0.41%), and vNWU was 11% (95%CI: 1.3–23.4), which was not statistically different (p = 0.09). Two patients showed significant differences between cNWU and vNWU (Δ = 24% and Δ = 36%), while the agreement of cNWU/vNWU in 8/10 patients was high (difference 2.3%, p = 0.23).Conclusion: NWU may be quantified precisely on conventional CT images, as the underestimation of ischemic edema due to contrast staining was low. However, a proportion of patients after MT might show significant contrast leakage resulting in edema underestimation. Further research is needed to validate these findings and investigate clinical implications.

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References[1] Afolalu EF, Ramlee F, Tang NKY. Effects of sleep changes on pain-related health outcomes in the general population: a systematic review of longitudinal studies with exploratory meta-analysis.

In the early phase of the COVID pandemic 2020, we demonstrated how patients with painful polyneuropathy, against our expectations, did not experience a deterioration of their neuropathic pain. We hypothesized that our assessed measures, that is, pain intensity and characteristics, emotional wellbeing, and everyday life, would deteriorate in the further course of the pandemic according to the phases of disaster management. Thus, the aim of our study was to investigate patients repeatedly under varying pandemic conditions from March until December 2020. Sixty-three patients were investigated with validated questionnaires (brief pain inventory [BPI], neuropathic pain symptom inventory [NPSI], pain catastrophizing scale [PCS], patient-reported outcomes measurement information system [PROMIS] pain interference/sleep disturbance/fatigue/ depression/anxiety, EuroQol 5 dimensions 5 level version [EQ-5D-5L]) and a pandemic-specific, self-designed questionnaire. The data from the beginning of the pandemic with severe restrictions, during summer with loosened regulations and from December 2020 with reinstalled, severe restrictions were compared with an observational design. Patients reported higher pain severity when restrictions were lower. Sleep, mood, and quality of life did not change in the course of the pandemic in the validated measures. Pain interference significantly decreased during the study independent from restrictions. Patients who reported medical disadvantages had a lower quality of life upon EuroQol 5 dimension (EQ-5D) and were significantly more worried about their health. The perception of pain intensity was dependent on pandemic severity. Sleep, mood, and quality of life did not change significantly in validated measures. Continued medical care seems decisive to prevent worsening of pain and quality of life.Abbreviations: BPI = brief pain inventory, COVID-19 = coronavirus disease 2019, EQ-5D = EuroQol 5 dimension, PCS = pain catastrophizing scale, PROMIS = patient-reported outcomes measurement information system.