The Use Of Transcranial Doppler Ultrasonography In Adult Patients With Sickle Cell Disease: A Retrospective Analysis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4692-4692 ◽  
Author(s):  
Sofia Galli ◽  
Soundrie Padayachee ◽  
Jo Howard
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Stroke Risk ◽  
Cell Disease ◽  
Carotid Duplex ◽  
Group I ◽  
Ultrasound Findings ◽  
Group Ii ◽  
Ica Stenosis ◽  
Extracranial Ica

Background Unlike in children, Transcranial Doppler Ultrasound (TCD) can not currently be used to predict stroke risk in adults with Sickle Cell Disease, and this is confounded by an age related decline in TCD and lack of an established normal TCD velocity range for adults. In addition abnormalities in the extracranial circulation have been associated with increased incidence of stroke in children with SCD, but this has not been shown in adults. Aims To retrospectively review TCD and carotid duplex ultrasound results from adults with SCD and to correlate with neurological outcome. Methods TCD and carotid duplex data were collected from 112 patients from January 2003 to December 2012 and analysed retrospectively. Imaging and non-imaging TCD and carotid duplex were performed as a routine out-patient investigation as part of an annual review in the comprehensive adult sickle cell clinic in our unit. STOP velocity criteria were used for stroke risk stratification. Carotid disease was defined as non-significant (<50%), moderate stenosis (50-69%) and severe disease (≥70%). Results The mean age of patients was 35.4 (range 17-79) years; 65% were female and 78% had HbSS. There were 5 patient exclusions based on the TCD findings; two were non-diagnostic and three had abnormal scans as part of childhood screening. The remaining 107 patients were divided into two groups; Group I patients had a normal neurological examination (n = 95) and Group II had an abnormal neurological examination with a clinical diagnosis of stroke that preceded TCD/carotid duplex examination (n = 12). In Group I there were 4 abnormal TCD scans according to STOP criteria; two showed significant asymmetry (>25%) and two showed abnormally low velocities (<50cm/s), one of whom subsequently developed a silent stroke. Although the remaining 91 patients had normal TCD findings; a limited TCD examination was noted in 6 patients and asymmetrical velocities that fell below the 25% threshold were observed in 7 patients, one of whom subsequently developed a symptomatic lacunar infarct. A further eight patients showed extracranial (ICA) disease and one of these also had evidence of a silent stroke on MRI. In Group II, 5 patients showed abnormal TCD findings; four had low velocities (<50cm/sec) and one had low velocities and significant asymmetry. Six patients had severe extracranial ICA stenosis or occlusion on carotid duplex. There was a significant increase in the incidence of abnormal TCD (C2=19.4, p<0.001) and duplex findings (C2=16.2, p<0.001) in patients in Group II compared to Group I. Conclusions Routine screening of adults with SCD using TCD did not show any asymptomatic patients with elevated TCD flow-velocities (>170cm/s), confirming previous studies. However, other abnormal ultrasound findings were observed including; abnormally low or asymmetric TCD velocities and extracranial ICA disease. These abnormalities were associated with stroke in three cases; TCD asymmetry preceded a lacunar infarct by five years, abnormally low velocities preceded a silent infarct by two years and severe extracranial ICA stenosis was associated with a silent infarct. There was a significantly increased incidence of abnormal ultrasound findings in patients who had neurological symptoms (91.6% versus 12.6%). Further investigation of the incidence and implications of abnormal TCD and extracranial carotid duplex findings in adults with sickle cell disease is required. Longitudinal follow-up of patients with low or asymmetric velocities and ICA disease will clarify if these abnormalities are associated with increased neurological morbidity; if so, intervention may be justified. The traditional STOP criteria of raised TCD velocities are inadequate in the adult sickle population, new velocity criteria are required to stratify the risk of stroke in this population. Disclosures: Howard: Sangart: Membership on an entity’s Board of Directors or advisory committees.

Right-To-Left Shunts (Extra-Cardiac Arterial-Venous Malformations) Are Highly Common In Adults With Sickle Cell Disease

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1004-1004
Author(s):  
Nathan Langer ◽  
MaryAnn O'Riordan ◽  
Santosh K. Rao ◽  
Jane A. Little ◽  
Robert Schilz
Keyword(s):  
Sickle Cell Disease ◽  
General Population ◽  
Oxygen Saturation ◽  
Sickle Cell ◽  
Morbidity And Mortality ◽  
Acute Chest Syndrome ◽  
Venous Malformations ◽  
Cell Disease ◽  
Group I ◽  
Group Ii

Abstract Introduction Cardiopulmonary complications are a major cause of morbidity and mortality in sickle cell disease (SCD) as shown by worse prognosis in patients who have experienced acute chest syndrome or who have an elevated tricuspid regurgitant jet velocity (TRV) on echocardiogram at clinical baseline. Here we describe an unexpected and novel cardio-pulmonary complication in HbSS, right-to-left shunting through extra-cardiac arterial-venous malformations (AVMs), which may contribute to pathophysiology. Extracardiac AVMs are rare in the general population, with an estimated incidence of 1/5000. Of 2111 shunt evaluation echocardiograms performed at our institution over 12 months only 81 (3.8%) of individual studies were positive. Methods We evaluated 36 HbSS patients who presented with subjective dyspnea or hypoxia with clinical exam and with echocardiogram utilizing agitated saline to assess for vascular right-to-left shunts. We compared this group with the remaining 81 HbSS patients in our database. 19 of 36 symptomatic patients were found to have an extracardiac right-to-left shunt. We then compared these 19 patients with the 17 symptomatic HbSS patients who did not have a shunt. 10 HbSC and 5 S-beta-thalassemia patients were also studied and did not have a right-to-left shunt; only HbSS are included in comparative analyses. Results Patients with symptoms did not differ in age (32.7±10.3 years vs 31.7±11.7 years) from patients who did not present with hypoxia or subjective dyspnea (n=81). Symptomatic patients were more likely to have macroalbuminuria (>300 mg/g albumin-to-creatinine, 9/36 vs 8/63 evaluable, p=0.05), more likely to have a TRV ≥3 meters/second (9/36 vs 11/74 evaluable, p=0.09), and were more hypoxic at rest (96 ±5% vs 98±2% oxygen saturation, p=0.07). We found delayed left-sided bubble visualization in 19/36 symptomatic HbSS subjects (53%) consistent with extra-cardiac AVMs. HbSS subjects with (n=19, Group I) or without (n=17, Group II) a positive bubble study were clinically and demographically similar (age, gender, WBC, total Hgb, HgbF%, LDH, eGFR, proportion with macroalbuminuria, baseline oxygen saturation, and elevated TRV). However, group I patients had a higher reticulocyte count (15.4±5.5% vs 9.8±6.7% p<0.005). Of Group I patients, 42.1% had history of acute chest while 70.6% of Group II had such history (p=0.09). Group I patients were less likely to be on hydroxyurea (52.78% vs 47.22% p<0.05). Conclusion Extra-cardiac AVMs are observed in 16% of all subjects with HbSS, compared with 3.8% of general medical patients at a tertiary center undergoing shunt evaluation and .02% in the general population. In HbSS, symptomatic subjects are more likely to have evidence for vasculopathy (macroalbuminuria, elevated TRV) and hypoxia; one-half of these symptomatic patients have extracardiac AVMs. We speculate that this finding is unlikely to be clinically silent, and a bubble-echocardiogram may be an important additional clinical evaluation for symptomatic dyspnea or hypoxia. The impact of this novel clinical finding on morbidity and mortality in this disease remains under investigation. Disclosures: No relevant conflicts of interest to declare.

Characterization of Pain, Vasculature and Innervation in Sickle Cell Disease.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2248-2248
Author(s):  
Kalpna Gupta ◽  
Chunsheng Chen ◽  
Marna E. Ericson ◽  
Robert P. Hebbel ◽  
Yunfang Li
Keyword(s):  
Sickle Cell Disease ◽  
Blood Vessels ◽  
Sickle Cell ◽  
Thermal Hyperalgesia ◽  
Cell Disease ◽  
Morphine Treatment ◽  
Group I ◽  
Group Ii ◽  
And Control

Abstract Pain in sickle cell disease (SCD) is characterized by chronic vasculopathy. Characterization of pain and vasculature may be critical to improve the analgesic ability of opioids in treating pain in SCD. Therefore, we examined the association between vasculature, innervation and pain in a transgenic mouse model of SCD (BERK) and control mice (HbABERK). Pain behavior was analyzed using paw withdrawal latencies (PWL) using Hargreave’s device for thermal hyperalgesia. A radiant heat stimulus was applied to the plantar surface of each hind paw from underneath the glass floor with a projector lamp bulb (CXL/CXR, 8 V, 50 W). PWL to the nearest 0.1 s was automatically recorded upon paw withdrawal. Paws were alternated randomly to preclude “order” effects. We observed that 5 mo old sickle mice showed significantly lower thresholds to noxious heat than controls (p=0.002 for females; and p=0.04 for males; n=5–7 and 15 observations/mouse). Females showed a significantly shorter latency than their respective males (control, p=0.03 and sickle, p=0.01), i.e., they were more sensitive to thermal stimuli. No significant difference was observed between sickle and control nor male and female mice (p &gt; 0.05, n = 5–7) for mechanical allodynia using von Frey filaments, suggesting that sickle mice show increased sensitivity to thermal hyperalgesia. BERK mice were subcutaneously injected with 0.7 mg morphine/Kg mice/day (equivalent to 50 mg/70 kg /day/ human adult) with an added increment of 0.14 mg/day/Kg for each week for three different time periods; Group I, treated for 6 weeks, Group II treated for 6 weeks followed by withdrawal for 6 weeks and Group III treated for 12 weeks. Morphine treatment for 6 weeks as well as 12 weeks resulted in a ∼50–75% increase in PWL vs PBS, suggesting that chronic morphine treatment decreased hyperalgesia in sickle mice. The anti-hyperalgesic effect of morphine was antagonized by simultaneous co-administration of naloxone (2 mcg/Kg/day), suggesting an opioid receptor mediated effect. Naloxone treatment alone did not show any significant effect on PWL. In Group II, withdrawal of morphine for 6 weeks following 6 wks of treatment showed about 35% increase in PWL vs PBS (p&lt;0.005), suggesting that the anti-hyperalgesic effect of morphine continues after its withdrawal. The continued anti-hyperalgesic effect of morphine following withdrawal could be secondary to its vasoregulatory effect. Indeed, confocal microscopy of skin sections revealed disorganized and stringy blood vessels, nerves and lymphatics in sickle mice vs. control. Deep blood vessels and nerve plexus, as well as the skin, were appreciably thicker in controls vs sickle. The diameter of lymphatics and densities of both blood vessels and nerves were significantly lower in sickle vs HbA controls (p= 0.0001 and 0.002, for sub-epidermal and dermal blood vessels, respectively; p=0.04 for lymphatic diameter; p=0.0001 for sub-epidermal, dermal and deep dermal nerve fibers). Functionally, we observed about 30% decrease in subcutaneous O2 measured by Laser Doppler (in real-time) in BERK vs HbA control (p&lt;0.05). Thus, complementary alteration in vasculature and innervation may underlie the chronic pain in SCD. Given that morphine promotes angiogenesis and vasodilation, its prolonged anti-hyperalgesic activity could be due to its vasoregulatory function. Together, these data suggest that intermittent therapy with morphine in SCD may provide analgesia similar to continued therapy and may even be devoid of side-effects.

Von Willebrand Factor in Sickle Cell Disease - Relationship to Sleep Hypoxia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1240-1240
Author(s):  
Suba Krishnan ◽  
Gene Pullen ◽  
Megan Hevelov ◽  
Jamie Siegel ◽  
B.N.Y. Setty ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Cell Disease ◽  
Mean Values ◽  
Group I ◽  
Platelet Aggregometry ◽  
Endothelial Response ◽  
Group Ii ◽  
Student’S T

Abstract Introduction: Despite the intriguing in vitro data implicating vWF in sickle-RBC-endothelial adhesion and in animal models of vasoocclusion, there are few clinical studies characterizing the role of vWF in SCD pathophysiology. Rationale: Plasma vWF is mainly endothelial-derived, upto 95% of newly synthesized vWF being secreted constitutively. Since in vitro studies have shown that hypoxia mediates release of ultra-large vWF multimers stored in endothelial Weibel Palade bodies, we hypothesized that changes in the plasma vWF profile of patients with sickle cell disease (SCD) could potentially be related to their oxygenation status and subsequent clinical events. Patient groups: Following informed consent blood samples were obtained from 20 children with SCD who were enrolled in an investigation of sleep hypoxia. After an awake blood oxgygen saturation by pulse oximetry (SaO2), an overnight recording was performed and a histogram generated showing proportions of time spent at various SaO2s. On the basis of mean sleeping SaO2s, the study population was divided into Group I (Normoxia, sleeping SaO2>94%, n=10) and Group II (Hypoxia, sleeping SaO2 <94%, n=10). Methods: VWF antigen level (vWF antigen) was determined by a latex enhanced immunoassay and Ristocetin Cofactor activity (RCof) was evaluated by platelet aggregometry. VWF multimer analysis was performed on SDS- 1.6% agarose gels and visualized using a polyclonal rabbit anti-human VWF antibody (Dako) followed by chemiluminescent detection using horse radish peroxidase-conjugated anti-rabbit IgG (Amersham). The presence of high molecular weight VWF multimers had to fulfill the following three criteria: (a) vWF multimers larger than the largest vWF multimers present in pooled normal plasma;(b)vWF multimers similar to the largest multimers present in a post-DDAVP infusion plasma sample analyzed on the same gel;(c) assessment by three independent investigators. Student’s t-test was performed to compare the mean values of vWFAg, vWF:RCof, and vWF RCof:Ag ratio of Gps I and II. Results: We observed significant differences between normoxic vs. hypoxic children with SCD as depicted in the table below where results are shown as Mean values(1SD). vWF antigen levels correlated inversely (r2=0.28) and vWF RCof:Ag ratios correlated positively (r2=0.2) with sleeping SaO2s. vWF:Ag* vWF RCof vWF RCof:Ag Ratios** HMW-vWF *p <0.003; **p <0.006 Group I >/94% 120.8(30.9) 116.7 (36.8) 0.96(0.1) 0/7 (performed to date) Group II <94% 192.2 (69.4) 147.3 (71.3) 0.77(0.14) 4/5 (performed to date) Conclusions: Children with SCD and sleep hypoxia showed abnormalities in their vWF profiles when compared to normoxic children with SCD including elevated vWF antigen and qualitatively increased HMW multimers suggestive of hypoxia-mediated endothelial response. In addition, there is an unexpected discordance between these findings and decreased vWF RCof:Ag ratios. Since children with SCD and nocturnal hypoxemia have an increased rate of pain-associated vasoocclusion and CNS complications, our findings of vWF-related perturbations could provide an explanation for hypoxia-induced modulation of the proadhesive and prothrombotic state in these children.

scholarly journals Transcranial Doppler screening for stroke risk in children with sickle cell disease: a systematic review

2017 ◽  
Vol 12 (6) ◽  
pp. 580-588 ◽  
Author(s):  
Sara Mazzucco ◽  
Marina Diomedi ◽  
Amrana Qureshi ◽  
Laura Sainati ◽  
Soundrie T Padayachee
Keyword(s):  
Systematic Review ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Transcranial Doppler ◽  
Stroke Risk ◽  
Screening Methods ◽  
Cell Disease ◽  
High Quality ◽  
Screening Practices

Background Sickle cell disease (SCD) is one of the most common causes of stroke in children worldwide. Based on the results of the Stroke Prevention Trial in Sickle Cell Anemia (STOP), annual transcranial Doppler ultrasound (TCD) screening for affected children is standard practice. However, the need for TCD surveillance programs could override the accuracy of the screening, affecting the correct stratification of stroke risk and subsequent clinical management of the target population. Aims To shed light on this issue, a systematic review of the literature on TCD screening for children and adolescents with SCD was carried out (CRD42016050549), according to a list of clinically relevant questions, with a particular focus on screening practices in European countries. Quality of the evidence was rated using the grading of recommendations assessment, development and evaluation. Summary of review Thirty-three studies published in English or French were included (5 randomized controlled trials, 8 experimental non-randomized, and 20 observational studies). The quality of the retrieved evidence ranged between low and high, but was rated as moderate or high most of the times. TCD is effective as a screening tool for the primary prevention of stroke in SCD children. There is no high-quality evidence on the effectiveness of alternative screening methods, such as imaging-TCD with or without angle correction or magnetic resonance angiography. No evidence was found on effectiveness of the screening on children on hydroxyurea and with genotypes other than HbSS and HbS/β0. No European data were found on screening rates or adherence of screening practices to the STOP protocol. Conclusions High-quality studies on alternative screening methods that are currently used in real-world practice, and on screening applicability to specific subgroups of patients are urgently needed. Considering the low awareness of the disease in European countries and the lack of data on screening practices and adherence, clinicians need up-to-date guidelines for more uniform and evidence-based surveillance of children with SCD.

Transcranial Doppler scanning and the assessment of stroke risk in children with haemoglobin sickle cell disease

2007 ◽  
Vol 93 (2) ◽  
pp. 138-141 ◽  
Author(s):  
Colin R Deane ◽  
David Goss ◽  
Sandra O’Driscoll ◽  
Sarah Mellor ◽  
Keith R E Pohl ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Transcranial Doppler ◽  
Stroke Risk ◽  
Cell Disease

scholarly journals Reduced Cerebrovascular Reserve Capacity in Adults with Sickle Cell Disease

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 972-972
Author(s):  
Lena Vaclavu ◽  
Lena Vaclavu ◽  
Henri JMM Mutsaerts ◽  
Esben Thade Petersen ◽  
Ed T VanBavel ◽  
...  
Keyword(s):  
White Matter ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Stroke Risk ◽  
Adult Patients ◽  
Healthy Controls ◽  
Cell Disease ◽  
Cerebrovascular Reserve ◽  
Cerebral Vasodilation ◽  
O2 Delivery

Abstract Introduction: Sickle Cell Disease (SCD) is frequently complicated by stroke. Although transcranial Doppler effectively identifies children at risk for stroke, adult patients do not benefit from this test. In SCD, chronic hemolytic anemia leads to cerebral vasodilation, elevated cerebral blood flow (CBF) and subsequently, impaired cerebrovascular reserve (CVR) capacity. CVR represents the maximum increase in CBF in response to metabolic stressors. CVR mapping is a promising imaging biomarker for stroke risk assessment, potentially identifying patients with preclinical hemodynamic impairment. Our laboratory performs CVR mapping by measuring CBF prior to and following maximum cerebral vasodilation with acetazolamide (ACZ). The primary aim of this study was to quantitatively assess CVR in adult patients with SCD compared to healthy controls. Methods: Adult SCD patients (HbSS/HbSβ0) were recruited for this IRB-approved study with ACZ-induced vasodilation and venous blood sampling. Patients with a history of clinically overt stroke were excluded. Controls were selected from patients' friends and family members without SCD and matched on age, sex, and race. The following MRI images were acquired at 3T (Philips Healthcare, Best, NL): time of flight MRA for visualization of major cerebral vessels, T2 FLAIR for manual segmentation of white matter hyperintensities (WMHs), and pseudo-continuous arterial spin labeling (ASL) for CBF assessment. CBF was measured at baseline and 10min post ACZ (16mg/kg intravenous infusion over 3min). MRI images were processed with the ExploreASL toolbox, to obtain registered maps of quantified CBF and CVR (% change in CBF). We measured T1blood in each subject to improve quantification accuracy as these values can differ in SCD. Group comparisons were performed using non-parametric two-sample tests. Correlations were characterized by Spearman's rho (ρ). P&lt;0.05 was considered significant. Median values with interquartile range (IQR) are reported for non-normally distributed variables, otherwise mean and standard deviation are reported. Results: 30 patients with SCD (mean age 33±12y,19M) and 11 controls (mean age 37±15y, 6M) were included in this cross-sectional controlled cohort study. Mean hemoglobin levels in patients with SCD were 8.8±1.4 g/dL and in healthy controls were 13.7±1.3 g/dL. Patients with SCD had higher baseline CBF compared to healthy controls (median 73(IQR:25) vs 42(IQR:6) mL/100g/min, p&lt;0.001, F1a). CBF was inversely related to hemoglobin (ρ=-0.84, p&lt;0.001, F1b). ACZ elicited an increase in CBF(p&lt;0.001) which was similar in magnitude in both groups (patients 29±16, controls 35±11, mL/100g/min, F1c), resulting in a lower mean CVR in patients compared to controls (41±24% vs 81±27%, p&lt;0.001, F1d). Baseline CBF predicted CVR (ρ=-0.68, p&lt;0.001, F1e). WMHs were present in both groups, and WMH volume correlated with age (ρ = 0.54, p&lt;0.001). There were no statistical associations between WMH volume and CVR (ρ = -0.15, p=0.4) or CBF(ρ = 0.02, p=0.9), however, two patients with the largest WMH volume (&gt;6 mL) had the lowest CVR (&lt;20%). Discussion: This study shows that regional CVR can be measured using ASL-MRI with ACZ challenge. ACZ was well-tolerated and elicited a robust cerebrovasodilatory response in both groups. However, the relative increase in oxygen delivery (CVR) was much lower in SCD patients, which suggests that patients with SCD have nearly maximal cerebrovascular dilation at baseline. Our data suggest that chronic vasodilation due to anaemia has let to outward remodelling of vessels in adult patients, permitting a larger vascular bed to compensate their anemia. Our premise is that resting O2 delivery is normal in SCD patients; we showed that increasing CBF overcomes severe anemia. However, high resting CBF limits the brain's ability to recruit additional O2 under times of stress. SCD patients have many transient interruptions in O2 delivery including aplastic crisis, splenic sequestration and sleep apnea, as well as metabolic stressors such as fever, sickle cell crisis, infection, and seizure. While baseline CBF predicted global CVR, ASL provides information regarding regional O2 delivery that may offer insight into distribution of ischemic white matter damage. Further study is needed to determine the impact of blood transfusions and hydroxyurea on CVR and whether there is a critical CVR threshold that predicts stroke risk. Disclosures No relevant conflicts of interest to declare.

scholarly journals Neurological Soft Signs as the Stroke Risk in Sickle Cell Disease

2006 ◽  
Vol 209 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Ismet Melek ◽  
Ferit Akgul ◽  
Taskin Duman ◽  
Fatih Yalcin ◽  
Edip Gali
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Stroke Risk ◽  
Cell Disease ◽  
Neurological Soft Signs

Abstract WMP97: Regional Cerebral Oxygen Extraction is Elevated in Tissue at High Risk of Stroke in Pediatric Sickle Cell Disease

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Andria L Ford ◽  
Kristin P Guilliams ◽  
Melanie Fields ◽  
Dustin K Ragan ◽  
Cihat Eldeniz ◽  
...  
Keyword(s):  
High Risk ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Retrospective Cohort ◽  
Stroke Risk ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cell Disease ◽  
Heat Map ◽  
Spin Echo Sequence

Introduction: Children with sickle cell disease (SCD) are at high risk of stroke. Hemispheric oxygen extraction fraction (OEF) is a predictor of stroke in adults with carotid occlusion, but OEF has not been evaluated as a predictor of stroke in children with SCD. Hypothesis: OEF is elevated in SCD children compared to controls within a region at high risk of stroke as defined by an infarct heat-map created from a separate retrospective SCD cohort. Methods: A prospective MRI study enrolled 37 children aged 5-21: 17 with SCD and no stroke, 12 with SCD and silent infarcts (median infarct volume=0.3ml), and 8 sibling controls. None were on transfusions or had overt stroke history. Voxel-wise OEF was measured using an asymmetric spin echo sequence. In a separate retrospective cohort of 67 SCD children with overt and silent stroke, infarct regions on FLAIR were manually outlined and coregistered to an average T1 map to create an infarct heat-map (Fig A) which was used to define a “high risk” ROI (defined by >3% infarct density). This ROI was aligned to individual OEF maps from the prospective cohort (Fig B, average OEF map). OEF within the “high risk” ROI was compared between SCD children and controls; and between SCD children with and without infarction using Mann Whitney U tests. Results: The infarct heat-map from the retrospective cohort (Fig A) and the average OEF map from the prospective SCD cohort (Fig B) demonstrate striking co-localization of infarct density and elevated OEF. Within the “high risk” ROI, OEF was higher in SCD children compared to controls (39% [36, 46] vs. 23% [22, 27], p<0.0001 (Fig C). OEF within this “high risk” ROI did not differ between SCD children with and without infarcts (40% [38, 47] vs. 38% [35, 46], p=0.6). Conclusion: OEF in SCD children is elevated in the internal borderzone, a region with high stroke risk in SCD. Regional OEF may be a marker of cerebral metabolic stress that could be exploited to stratify stroke risk in this vulnerable population.

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