Normalization of cerebral hemodynamics after hematopoietic stem cell transplant in children with sickle cell disease.

Children with sickle cell disease (SCD) demonstrate cerebral hemodynamic stress and are at high risk of strokes. We hypothesized that curative hematopoietic stem cell transplant (HSCT) normalizes cerebral hemodynamics in children with SCD compared with pre-transplant baseline. Whole-brain cerebral blood flow (CBF) and oxygen extraction fraction (OEF) were measured by magnetic resonance imaging 1 to 3 months before and 12 to 24 months after HSCT in 10 children with SCD. Three children had prior overt strokes, 5 children had prior silent strokes, and 1 child had abnormal transcranial Doppler ultrasound velocities. CBF and OEF of HSCT recipients were compared with non-SCD control participants and with SCD participants receiving chronic red blood cell transfusion therapy (CRTT) before and after a scheduled transfusion. Seven participants received matched sibling donor HSCT, and 3 participants received 8 out of 8 matched unrelated donor HSCT. All received reduced-intensity preparation and maintained engraftment, free of hemolytic anemia and SCD symptoms. Pre-transplant, CBF (93.5 mL/100 g/min) and OEF (36.8%) were elevated compared with non-SCD control participants, declining significantly 1 to 2 years after HSCT (CBF, 72.7 mL/100 g per minute; P = .004; OEF, 27.0%; P = .002), with post-HSCT CBF and OEF similar to non-SCD control participants. Furthermore, HSCT recipients demonstrated greater reduction in CBF (-19.4 mL/100 g/min) and OEF (-8.1%) after HSCT than children with SCD receiving CRTT after a scheduled transfusion (CBF, -0.9 mL/100 g/min; P = .024; OEF, -3.3%; P = .001). Curative HSCT normalizes whole-brain hemodynamics in children with SCD. This restoration of cerebral oxygen reserve may explain stroke protection after HSCT in this high-risk patient population.

GRAPES: Trivia game increases sickle cell disease knowledge in patients and providers and mitigates healthcare biases.

BACKGROUND: Patients with sickle cell disease (SCD) endure healthcare biases that are partially due to a lack of disease-specific education among healthcare providers. Furthermore, there is a paucity of age-appropriate health education materials for patients with SCD. To address this gap, we created the GRAPES tool (Game to Raise Awareness for Patient/Provider/Public Education of SCD; www.tinyurl.com/GRAPESgame) and hypothesized that utilization of the GRAPES tool will improve patient and provider SCD knowledge and mitigate healthcare bias. PROCEDURE: The GRAPES tool is an online, single-player trivia game. A feasibility study was conducted in pediatric patients with SCD at age 10 years or older and registered nurses. All participants were assessed for change in SCD-relevant knowledge and satisfaction post-gameplay. Providers were assessed for change in attitudes toward patients with SCD post-gameplay. RESULTS: Twenty-five patients and 25 providers were enrolled. All participants (P < 0.001), and specifically within the patient (P = 0.019) and provider (P < 0.001) cohorts, showed increased SCD knowledge post-gameplay. Both patients and providers reported high satisfaction with GRAPES. Provider negative attitudes were reduced (P = 0.007) post-gameplay without change in positive attitudes (P = 0.959). Providers demonstrated post-gameplay reduced (P = 0.001) belief that patients' changing behavior around providers indicates inappropriate drug-seeking behavior. CONCLUSIONS: This study demonstrates the feasibility and acceptability of the GRAPES tool as a potential digital, behavioral intervention to provide educational materials for patients and their providers in different clinical settings, improve knowledge about SCD, and decrease stigma against patients with SCD in the healthcare setting.

MR-assisted PET respiratory motion correction using deep-learning based short-scan motion fields.

PURPOSE: We evaluated the impact of PET respiratory motion correction (MoCo) in a phantom and patients. Moreover, we proposed and examined a PET MoCo approach using motion vector fields (MVFs) from a deep-learning reconstructed short MRI scan. METHODS: The evaluation of PET MoCo was performed in a respiratory motion phantom study with varying lesion sizes and tumor to background ratios (TBRs) using a static scan as the ground truth. MRI-based MVFs were derived from either 2000 spokes (MoCo2000 , 5-6 min acquisition time) using a Fourier transform reconstruction or 200 spokes (MoCoP2P200 , 30-40 s acquisition time) using a deep-learning Phase2Phase (P2P) reconstruction and then incorporated into PET MoCo reconstruction. For six patients with hepatic lesions, the performance of PET MoCo was evaluated using quantitative metrics (SUVmax , SUVpeak , SUVmean , lesion volume) and a blinded radiological review on lesion conspicuity. RESULTS: MRI-assisted PET MoCo methods provided similar results to static scans across most lesions with varying TBRs in the phantom. Both MoCo2000 and MoCoP2P200 PET images had significantly higher SUVmax , SUVpeak , SUVmean and significantly lower lesion volume than non-motion-corrected (non-MoCo) PET images. There was no statistical difference between MoCo2000 and MoCoP2P200 PET images for SUVmax , SUVpeak , SUVmean or lesion volume. Both radiological reviewers found that MoCo2000 and MoCoP2P200 PET significantly improved lesion conspicuity. CONCLUSION: An MRI-assisted PET MoCo method was evaluated using the ground truth in a phantom study. In patients with hepatic lesions, PET MoCo images improved quantitative and qualitative metrics based on only 30-40 s of MRI motion modeling data.

Rate of Infarct-Edema Growth on CT Predicts Need for Surgical Intervention and Clinical Outcome in Patients with Cerebellar Infarction.

BACKGROUND: Up to 20% of patients with cerebellar infarcts will develop malignant edema and deteriorate clinically. Radiologic measures, such as initial infarct size, aid in identifying individuals at risk. Studies of anterior circulation stroke suggest that mapping early edema formation improves the ability to predict deterioration; however, the kinetics of edema in the posterior fossa have not been well characterized. We hypothesized that faster edema growth within the first hours after acute cerebellar stroke would be an indicator for individuals requiring surgical intervention and those with worse neurological outcomes. METHODS: Consecutive patients admitted to the neurological intensive care unit with acute cerebellar infarction were retrospectively identified. Hypodense regions of infarct and associated edema, "infarct-edema", were delineated by using ABC/2 for all computed tomography (CT) scans up to 14 days from last known well. To examine how rate of infarct-edema growth varied across clinical variables and surgical intervention status, nonlinear and linear mixed-effect models were performed over 2 weeks and 2 days, respectively. In patients with at least two CT scans, multivariable logistic regression examined clinical and radiological predictors of surgical intervention (defined as extraventricular drainage and/or posterior fossa decompression) and poor clinical outcome (discharge to skilled nursing facility, long-term acute care facility, hospice, or morgue). RESULTS: Of 150 patients with acute cerebellar infarction, 38 (25%) received surgical intervention and 45 (30%) had poor clinical outcome. Age, admission National Institutes of Health Stroke Scale (NIHSS) score, and baseline infarct-edema volume did not differ, but bilateral/multiple vascular territory involvement was more frequent (87% vs. 50%, p < 0.001) in the surgical group than that in the medical intervention group. On 410 serial CTs, infarct-edema volume progressed rapidly over the first 2 days, followed by a subsequent plateau. Of 112 patients who presented within two days, infarct-edema growth rate was greater in the surgical group (20.1 ml/day vs. 8.01 ml/day, p = 0.002). Of 67 patients with at least two scans, after adjusting for baseline infarct-edema volume, vascular territory, and NIHSS, infarct-edema growth rate over the first 2 days (odds ratio 2.55; 95% confidence interval 1.40-4.65) was an independent, and the strongest, predictor of surgical intervention. Further, early infarct-edema growth rate predicted poor clinical outcome (odds ratio 2.20; 95% confidence interval 1.30-3.71), independent of baseline infarct-edema volume, brainstem infarct, and NIHSS. CONCLUSIONS: Early infarct-edema growth rate, measured via ABC/2, is a promising biomarker for identifying the need for surgical intervention in patients with acute cerebellar infarction. Additionally, it may be used to facilitate discussions regarding patient prognosis.

Patient-derived small intestinal myofibroblasts direct perfused, physiologically responsive capillary development in a microfluidic Gut-on-a-Chip Model.

The development and physiologic role of small intestine (SI) vasculature is poorly studied. This is partly due to a lack of targetable, organ-specific markers for in vivo studies of two critical tissue components: endothelium and stroma. This challenge is exacerbated by limitations of traditional cell culture techniques, which fail to recapitulate mechanobiologic stimuli known to affect vessel development. Here, we construct and characterize a 3D in vitro microfluidic model that supports the growth of patient-derived intestinal subepithelial myofibroblasts (ISEMFs) and endothelial cells (ECs) into perfused capillary networks. We report how ISEMF and EC-derived vasculature responds to physiologic parameters such as oxygen tension, cell density, growth factors, and pharmacotherapy with an antineoplastic agent (Erlotinib). Finally, we demonstrate effects of ISEMF and EC co-culture on patient-derived human intestinal epithelial cells (HIECs), and incorporate perfused vasculature into a gut-on-a-chip (GOC) model that includes HIECs. Overall, we demonstrate that ISEMFs possess angiogenic properties as evidenced by their ability to reliably, reproducibly, and quantifiably facilitate development of perfused vasculature in a microfluidic system. We furthermore demonstrate the feasibility of including perfused vasculature, including ISEMFs, as critical components of a novel, patient-derived, GOC system with translational relevance as a platform for precision and personalized medicine research.

Increased complications of chronic erythrocytapheresis compared with manual exchange transfusions in children and adolescents with sickle cell disease.

BACKGROUND: Children and adolescents with sickle cell disease (SCD) are at high risk of strokes and are frequently treated with red blood cell (RBC) transfusions. The goal is to suppress hemoglobin (Hb) S while minimizing transfusion-induced iron overload. RBCs may be given via simple transfusion, manual exchange transfusion (MET), or erythrocytapheresis (aRBCX). Chronic transfusion practices vary among institutions. METHODS: This single-institution, retrospective cohort study compares Hb S control and therapy complication rates between MET and aRBCX in a cohort of children and adolescents with SCD and stroke during a 5-year period from 2008 through 2012. Duration and mode of transfusion therapy, achievement of Hb S suppression goal, iron burden by ferritin levels, and catheter complications were evaluated. RESULTS: Thirty-seven children were included in analysis. The prevalence of catheter complications was 75% in aRBCX recipients compared with 0% in MET recipients (P < 0.001). There was no significant difference between modalities in achieving Hb S suppression or ferritin goals, but those receiving aRBCX had a greater likelihood of discontinuing chelation therapy. Among aRBCX recipients, adherence to >90% of transfusion appointments was associated with achieving Hb S suppression goals. CONCLUSION: aRBCX may have increased complication risks compared with MET for chronic transfusion therapy in SCD. Risks and benefits of aRBCX and MET should be considered when selecting a chronic transfusion modality. Transfusion therapy modalities should be compared in prospective studies for stroke prevention in children with SCD.

Large-Vessel Vasculopathy in Children With Sickle Cell Disease: A Magnetic Resonance Imaging Study of Infarct Topography and Focal Atrophy.

BACKGROUND: Large-vessel vasculopathy (LVV) increases stroke risk in pediatric sickle cell disease beyond the baseline elevated stroke risk in this vulnerable population. The mechanisms underlying this added risk and its unique impact on the developing brain are not established. METHODS: We analyzed magnetic resonance imaging and angiography scans of 66 children with sickle cell disease and infarcts by infarct density heatmaps and Jacobian determinants, a metric utilized to delineate focal volume change, to investigate if infarct location, volume, frequency, and cerebral atrophy differed among hemispheres with and without LVV. RESULTS: Infarct density heatmaps demonstrated infarct "hot spots" within the deep white matter internal border zone region in both LVV and non-LVV hemispheres, but with greater infarct density and larger infarct volumes in LVV hemispheres (2.2 mL versus 0.25 mL, P < 0.001). Additional scattered cortical infarcts in the internal carotid artery territory occurred in LVV hemispheres, but were rare in non-LVV hemispheres. Jacobian determinants revealed greater atrophy in gray and white matter of the parietal lobes of LVV compared with non-LVV hemispheres. CONCLUSION: Large-vessel vasculopathy in sickle cell disease appears to increase ischemic vulnerability in the borderzone region, as demonstrated by the increased frequency and extent of infarction within deep white matter, and increased risk of focal atrophy. Scattered infarctions across the LVV-affected hemispheres suggest additional stroke etiologies of vasculopathy (i.e., thromboembolism) in addition to chronic hypoxia-ischemia.