Stroke is common in children with sickle cell disease and results from an imbalance oxygen supply demand. Cerebral blood flow (CBF) increased patients to compensate for their anemia, but adequacy of delivery has not been systematically demonstrated. This study examined the physiological determinants CBF 37 disease, 38 ethnicity matched control subjects 16 anemia non‐sickle origin. was measured using phase contrast MRI carotid vertebral arteries. inversely content ( r 2 = 0.69, P <...

Purpose T 2 MRI oximetry can noninvasively determine oxygen saturation (Y) but requires empirical MR calibration models to convert the measured blood transverse relaxation (T 2b ) into Y. The accuracy of existing in presence disorders such as sickle cell disease (SCD) remains unknown. Methods A Carr Purcell Meiboom Gill preparation sequence was used make 83 whole measurements from 11 subjects with SCD derive an ex vivo hemoglobin (HbS) model. Forearm venous gas, sagittal sinus Relaxation...

Arterial stiffness is strongly associated with vascular aging and pathology can be assessed in many ways. Existing devices for measuring central arterial stiffness, such as carotid-femoral pulse wave velocity (PWV), are limited by high costs the need specialized expertise, limiting widespread clinical adoption. This study introduces a semi- non-occlusive PWV measurement system using phonocardiography (PCG) plethysmography (PPG) single femoral pressure cuff, aiming to address these...

Thromboembolic diseases are a significant cause of mortality and clinically treated enzymatically with tissue plasminogen activator (tPA). Interestingly, prior studies in fibrin fibers gels have demonstrated that thrombolysis may be mechanically sensitive. This study aims to expand mechano-lytic whole blood clots. Furthermore, this investigates not only how mechanics impacts lysis but also mechanics. Therefore, clots made from human exposed tPA while the either stretched or unstretched....

Rationale: Sickle cell disease is an inherited blood disorder characterized by vasoocclusive crises. Although hypoxia and pulmonary are known risk factors for these crises, the mechanisms that initiate events not well known.Objectives: To study relationship between transient hypoxia, respiration, microvascular flow in patients with sickle cell.Methods: We established a protocol mimics nighttime hypoxic episodes measured to determine if causes decrease flow. Significant desaturations were...

Sickle cell disease (SCD) is the most common cause of stroke in childhood and results primarily from a mismatch cerebral oxygen supply demand rather than arterial obstruction. However, resting blood flow (CBF) has not been examined general African American population, whom obesity, hypertension, cerebrovascular disease, diminished reserve capacity are common. To better understand underlying physiological substrate upon which SCD superimposed, we measured CBF 32 young (age 28 ± 10 yr),...

<h3>BACKGROUND AND PURPOSE:</h3> Children with sickle cell disease have low hematocrit and elevated CBF, the latter of which can be assessed arterial spin-labeling MR imaging. Quantitative CBF values are obtained by using an estimation longitudinal relaxation time blood (T1_blood). Because T1_blood depends on in healthy individuals, we investigated importance measuring vivo imaging versus calculating it from or assuming adult fixed value recommended literature,...

Although modern medical management has lowered overt stroke occurrence in patients with sickle cell disease (SCD), progressive white matter (WM) damage remains common. It is known that cerebral blood flow (CBF) increases to compensate for anemia, but sufficiency of oxygen delivery, especially the WM, not been systematically investigated. Cerebral perfusion was measured by arterial spin labeling 32 SCD (age range: 10‐42 years old, 14 males, 7 HbSC, 25 HbSS) and age race‐matched healthy...

Abstract Severe chronic anemia is an independent predictor of overt stroke, white matter damage, and cognitive dysfunction in the elderly. also predisposes to strokes young children, subtype. We previously demonstrated symmetrically decreased (WM) volumes patients with sickle cell disease (SCD). In current study, we investigated whether non‐sickle have lower WM dysfunction. Magnetic Resonance Imaging was performed on 52 clinically asymptomatic SCD (age = 21.4 ± 7.7; F 27, M 25; hemoglobin...

Purpose We sought a human blood T2-oximetery calibration curve over the wide range of hematocrits commonly found in anemic patients applicable with T2 relaxation under spin tagging (TRUST). Methods Blood was drawn from five healthy control subjects. Ninety-three vitro transverse (T2b) measurements were performed at 37°C broad (10–55%) and oxygen saturations (14–100%) 3 Tesla (T). In vivo TRUST on 35 African American subjects 11 chronic anemia syndromes. Results 1/T2 rose linearly hematocrit...

Sickle cell disease (SCD) is a life-threatening genetic condition. Patients suffer from chronic systemic and cerebral vascular that leads to early cumulative neurological damage. Few studies have quantified the effects of this on brain morphometry even fewer efforts been devoted older patients despite progressive nature disease. This study quantifies global regional volumes in adolescent young adult with SCD racially matched controls aim distinguishing between age related changes associated...

Purpose Gadolinium‐based dynamic susceptibility contrast (DSC) is commonly used to characterize blood flow in patients with stroke and brain tumors. Unfortunately, gadolinium administration has been associated adverse reactions long‐term accumulation tissues. In this work, we propose an alternative deoxygenation‐based DSC (dDSC) method that uses a transient hypoxia gas paradigm deliver bolus of paramagnetic deoxygenated hemoglobin the cerebral vasculature for perfusion imaging. Methods...

Anemia is the most common blood disorder in world. In patients with chronic anemia, such as sickle cell disease or major thalassemia, cerebral flow increases to compensate for decreased oxygen content. However, effects of anemia on extraction fraction (OEF) and metabolic rate (CMRO

Purpose Cerebral T 2 oximetry is a non‐invasive imaging method to measure blood and cerebral venous oxygenation. Measured values are converted estimates using carefully validated potentially disease‐specific calibrations. In sickle cell disease, red cells have abnormal shape membrane properties that alter calibration relationships in clinically meaningful ways. Previous vitro works by two independent groups established competing models. Methods This study analyzed pooled datasets from these...

Sickle cell disease (SCD) is a chronic blood disorder that often associated with acute and cerebrovascular complications, including strokes impaired cognition. Using functional resting state magnetic resonance images, we performed whole-brain analysis of the amplitude low frequency fluctuations (ALFF), to detect areas spontaneous oxygenation level dependent signal across brain regions. We compared ALFF 20 SCD patients observed in 19 healthy, age ethnicity-matched, control subjects....

Abstract We have previously demonstrated that sickle cell disease (SCD) patients maintain normal global systemic and cerebral oxygen delivery by increasing cardiac output. However, ischemic end‐organ injury remains common suggesting tissue may be impaired microvascular dysregulation or damage. To test this hypothesis, we performed fingertip laser Doppler flowmetry measurements at the base of nailbed regional saturation (rSO 2 ) on dorsal surface same hand. This was done during flow mediated...

Background Chronic transfusion therapy ( CTT ) is a mainstay for stroke prophylaxis in sickle cell anemia, but its effects on hemodynamics are poorly characterized. Transfusion improves oxygen‐carrying capacity, reducing demands high cardiac output, while decreasing hemoglobin Hb S %, reticulocyte count, and hemolysis. We hypothesized that would improve be counteracted by decrease output due to increased hematocrit (Hct) vascular resistance, leaving oxygen delivery unchanged. Study Design...

Sickle cell disease (SCD) is characterized by sudden onset of painful vaso-occlusive crises (VOC), which occur on top the underlying chronic blood disorder. The mechanisms that trigger VOC remain elusive, but recent work suggests autonomic dysfunction may be an important predisposing factor. Heart-rate variability has been employed in previous studies, derived indices have provided only limited univariate information about cardiovascular control SCD. To circumvent this limitation, a...

Sickle cell disease (SCD) is a monogenic hemoglobinopathy associated with significant morbidity and mortality. Cardiopulmonary, vascular sudden death are the reasons for majority of young adult mortality in SCD. To better understand clinical importance multi-level dysfunction, 2009 we assessed cardiac function including tricuspid regurgitant jet velocity (TRV), tissue systole(S') diastole (E'), inflammatory, rheologic hemolytic biomarkers as predictors patients With up to 9 years follow up,...

Quantitative T2 * MRI is the standard of care for assessment iron overload. However, patient motion corrupts estimates.To develop and evaluate a motion-robust, simultaneous cardiac liver imaging approach using non-Cartesian, rosette sampling model-based reconstruction as compared to clinical-standard Cartesian MRI.Prospective.Six ferumoxytol-containing phantoms (26-288 μg/mL). Eight healthy subjects 18 patients referred clinically indicated overload assessment.1.5T, 2D gradient echo (GRE)...

Background Obstructive sleep apnea and nocturnal oxygen desaturations, which are prevalent in sickle cell disease (SCD) chronic anemia disorders, have been linked to risks of stroke silent cerebral infarcts (SCI). Cerebrovascular response intermittent desaturations has not well studied may identify patients at greatest risk. Purpose To investigate the dynamic induced desaturation SCD with without SCI, anemia, healthy subjects. Study Type Prospective. Subjects Twenty‐six (age = 21 ± 8.2,...

Sickle cell disease (SCD) is a hereditary blood disorder in which the oxygen-carrying hemoglobin molecule red cells abnormal. It affects numerous people world and leads to shorter life span, pain, anemia, serious infections neurocognitive decline. Tract-Specific Analysis (TSA) statistical method evaluate white matter alterations due diseases, using diffusion tensor magnetic resonance images. Here, for first time, TSA used compare 11 major brain (WM) tracts between SCD patients age-matched...