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1.
J Am Soc Nephrol ; 32(2): 518-519, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36734842
2.
Br J Haematol ; 180(3): 432-442, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29270975

RESUMEN

Stroke risk in children with sickle cell disease (SCD) is currently assessed with routine transcranial Doppler ultrasound (TCD) measurements of blood velocity in the Circle of Willis (CoW). However, there is currently no biomarker with proven prognostic value in adult patients. Four-dimensional (4D) flow magnetic resonance imaging (MRI) may improve risk profiling based on intracranial haemodynamics. We conducted neurovascular 4D flow MRI and blood sampling in 69 SCD patients [median age 15 years (interquartile range, IQR: 12-50)] and 14 healthy controls [median age 21 years (IQR: 18-43)]. We measured velocity, flow, lumen area and endothelial shear stress (ESS) in the CoW. SCD patients had lower haematocrit and viscosity, and higher velocity, flow and lumen area, with lower ESS compared to healthy controls. We observed significant age-related decline in haemodynamic 4D flow parameters; velocity (Spearman's ρ = -0·36 to -0·61), flow (ρ = -0·26 to -0·52) and ESS (ρ = -0·14 to -0·54) in SCD patients. Further analysis in only adults showed that velocity values were similar in SCD patients compared to healthy controls, but that the additional 4D flow parameters, flow and lumen area, were higher, and ESS lower, in the SCD group. Our data suggest that 4D flow MRI may identify adult patients with an increased stroke risk more accurately than current TCD-based velocity.


Asunto(s)
Anemia de Células Falciformes/fisiopatología , Circulación Cerebrovascular , Hemodinámica , Imagen por Resonancia Magnética , Adolescente , Adulto , Factores de Edad , Anemia de Células Falciformes/sangre , Anemia de Células Falciformes/patología , Velocidad del Flujo Sanguíneo , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Estudios de Casos y Controles , Niño , Femenino , Hematócrito , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Viscosidad , Adulto Joven
3.
J Magn Reson Imaging ; 35(4): 779-87, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22095695

RESUMEN

PURPOSE: To evaluate the applicability of arterial spin labeling (ASL) cerebral blood flow (CBF) measurements in children with sickle cell disease (SCD). MATERIALS AND METHODS: We included 12 patients and five controls. Conventional magnetic resonance imaging (MRI) (T2, fluid attenuated inversion recovery [FLAIR], and MR angiography) was performed to diagnose silent infarcts, vasculopathy, or leukoencephalopathy. Pseudo-continuous ASL was performed to measure CBF using two postlabeling delays to identify transit-time effects. Perfusion estimates were corrected for hematocrit and blood velocity in the labeling plane and compared to phase-contrast MR. CBF asymmetries between the flow maps of the left and right internal carotid arteries were tested for significance using paired t-tests. Significant asymmetries were expressed in terms of an asymmetry ratio (AR = absolute difference/mean). An AR >10% was considered clinically relevant. RESULTS: Mean CBF was higher in patients than in controls. Agreement between CBF and flow improved after applying hematocrit and velocity corrections. At a 2100 msec postlabeling delay one patient had a clinically relevant asymmetry. No association was observed between CBF asymmetries and silent infarcts. CONCLUSION: Care must be taken in the interpretation of ASL-CBF measurements in SCD patients. A long postlabeling delay with blood velocity correction anticipates overestimation of CBF asymmetries.


Asunto(s)
Anemia de Células Falciformes/patología , Anemia de Células Falciformes/fisiopatología , Circulación Cerebrovascular , Trastornos Cerebrovasculares/patología , Trastornos Cerebrovasculares/fisiopatología , Angiografía por Resonancia Magnética/métodos , Adolescente , Anemia de Células Falciformes/complicaciones , Velocidad del Flujo Sanguíneo , Trastornos Cerebrovasculares/etiología , Niño , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Marcadores de Spin , Adulto Joven
4.
J Cereb Blood Flow Metab ; 31(8): 1706-15, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21304555

RESUMEN

Intra- and multicenter reproducibility of currently used arterial spin labeling (ASL) methods were assessed at three imaging centers in the Netherlands, equipped with Philips 3TMR scanners. Six healthy participants were scanned twice at each site. The imaging protocol consisted of continuous ASL (CASL), pseudo-continuous ASL (p-CASL) with and without background suppression, pulsed ASL (PASL) with single and multiple inversion times (TIs), and selective ASL for segmentation. Reproducibility was expressed in terms of the coefficient of repeatability and the repeatability index. Voxelwise analysis of variance was performed, yielding brain maps that reflected regional variability. Intra- and multicenter reproducibility were comparable for all methods, except for single TI PASL, with better intracenter reproducibility (F-test of equality of two variances, P<0.05). Pseudo-continuous ASL and multi TI PASL varied least between sites. Variability maps of all methods showed most variability near brain-feeding arteries within sessions and in gray matter between sessions. On the basis of the results of this study, one could consider the use of reference values in clinical routine, with whole-brain p-CASL perfusion varying <20% over repeated measurements within the same individuals considered to be normal. Knowledge on regional variability allows for the use of perfusion-weighted images in the assessment of local cerebral pathology.


Asunto(s)
Circulación Cerebrovascular/fisiología , Angiografía por Resonancia Magnética/métodos , Imagen de Perfusión/métodos , Flujo Sanguíneo Regional , Marcadores de Spin , Adulto , Arterias/fisiología , Encéfalo/irrigación sanguínea , Mapeo Encefálico/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados
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