Background
The high acoustic impedance of the skull limits the performance of transcranial magnetic resonance‐guided focused ultrasound (tcMRgFUS) therapy. Subject suitability screening is based on skull parameters estimated from computed tomography (CT) scans.
Purpose
To assess the feasibility of screening for tcMRgFUS based on zero echo time (ZTE) MRI, and to explore the influence of measurable skull parameters in treatment performance.
Study Type
Retrospective.
Population
Sixteen patients treated with tcMRgFUS thalamotomy for tremor.
Sequence
ZTE on a 3.0T GE scanner.
Assessment
Baseline CT and ZTE images were processed to extract skull measures associated with treatment success: skull density ratio (SDR), skull thickness, and angle of incidence. Eight new metrics were proposed. CT and ZTE‐based measures were compared. Each subject's energy–temperature curve was processed to extract a global estimate of efficiency and a measure of nonlinearity. These parameters were then correlated with the skull measures.
Statistical Tests
Linear regression analysis to compare ZTE vs. CT‐based measures, measures vs. efficiency, and measures vs. nonlinearity. Paired t‐test to assess nonlinearity.
Results
CT and ZTE‐based measures were significantly correlated (P < 0.01). In particular, classical metrics were robustly replicated (P < 0.001). The energy–temperature curves showed a nonlinear (logarithmic) relationship (P < 0.01). This nonlinearity was greater for thicker skulls (P < 0.01). Efficiency was correlated with skull thickness (P < 0.001) and SDR (P < 0.05).
Data Conclusion
The feasibility of ZTE‐based screening has been proven, potentially making it possible to avoid ionizing radiation and the extra imaging session required for CT. The characterization of the influence that skull properties have on tcMRgFUS may serve to develop patient‐specific heating models, potentially improving control over the treatment outcome. The relationship of skull thickness with efficiency and nonlinearity empowers the role of this metric in the definition of such models. In addition, the lower association of SDR with the energy–temperature curves emphasizes the need of revisiting this metric.
Level of Evidence: 3
Technical Efficacy: Stage 2
J. Magn. Reson. Imaging 2019;50:1583–1592.
LA ERRADICACIÓN DEL CHABOLISMO EN MADRID: LA NECESARIA COLABORACIÓN ENTRE ADMINISTRACIONES
El desmantelamiento de los grandes núcleos de chabolas de la capital.Las actuaciones contra el chabolismo y la marginalidad residencial llevadas a cabo en Madrid desde el surgimiento de la democracia en 1978 hasta 1986 se concretaron en la mayor actuación contra la infravivienda realizada en España hasta el momento y conocida como Operación Barrios en Remodelación que afectó a 28 barrios y realojó a 1.490.000 personas. Dicha actuación supuso la construcción de 38.540 viviendas, con una inversión de 310 millones de pesetas, y se extendió sobre 8.378 hectáreas de 12 distritos de la capital, como muestra la figura 1.Pero el programa de Barrios en Remodelación únicamente incluyó en sus actuaciones a 644 familias gitanas chabolistas que representaban en aquel momento el 1,8% de los realojamientos del programa, como muestra la figura 2.Concluida la actuación, el chabolismo dejo de ser considerado en Madrid como un fenómeno amplio que afectaba a una gran variedad de grupos sociales para circunscribirse casi en exclusiva a un problema que sufría la población gitana.
Introducción: La terapia anticoagulante oral es una herramienta esencial para prevenir eventos tromboembólicos. Los fármacos más utilizados para este propósito son los antagonistas de vitamina K, cuyo efecto se monitoriza con el International Normalized Ratio (INR). Existen varios factores que afectan el nivel de anticoagulación. Objetivo: Identificar los factores asociados a un INR fuera de rango terapéutico. Metodología: Estudio observacional de corte transversal que analizó los datos de pacientes en TACO, controlados en un policlínico especializado del Hospital Naval Almirante Nef.
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