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1.
Neuroradiology ; 60(1): 81-87, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29058047

RESUMEN

PURPOSE: Early in-stent restenosis after stent-protected angioplasty of the carotid artery (SPAC) is an infrequent, but potentially harmful condition for patients with carotid artery disease. METHODS: In our retrospective single-center analysis of 176 patients with carotid artery stenting between 2009 and 2015, using duplex ultrasound, we detected 9 patients with high-grade carotid artery in-stent restenosis. All restenosis patients were treated with a drug-eluting balloon (DEB) to prevent recurrent neointimal hyperplasia. One patient had bilateral carotid artery disease with bilateral in-stent restenosis, and 1 patient needed repeated DEB treatment 19 months after the first DEB intervention, so 11 DEB procedures, in total, were performed. RESULTS: The median time-interval between primary carotid artery stenting and first DEB-treatment was 9 months. In 3 of the 11 interventions, the DEB treatment was assisted by an additional stent. One repeat DEB treatment was necessary, and three DEB treatments were followed by a secondary stent. No peri-interventional complications (TIA, stroke, or death) were observed during or after DEB intervention. Therefore, in the entire group, the 1y event-free survival (EFS) was 100%, and the 2y/3y/5y EFS was 83%. CONCLUSION: DEB intervention seems to be an effective and safe treatment for patients with high-grade in-stent restenosis after SPAC.


Asunto(s)
Fármacos Cardiovasculares/administración & dosificación , Estenosis Carotídea/diagnóstico por imagen , Estenosis Carotídea/tratamiento farmacológico , Stents Liberadores de Fármacos , Ultrasonografía Doppler Dúplex , Anciano , Anciano de 80 o más Años , Procedimientos Endovasculares , Femenino , Humanos , Masculino , Persona de Mediana Edad , Inhibidores de Agregación Plaquetaria/administración & dosificación , Recurrencia , Estudios Retrospectivos , Resultado del Tratamiento
2.
J Magn Reson ; 175(2): 226-34, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15921938

RESUMEN

This article presents the realization of many self-reversible quantum logic gates using two-qubit quadrupolar spin 3/2 systems. Such operations are theoretically described using propagation matrices for the RF pulses that include the effect of the quadrupolar evolution during the pulses. Experimental demonstrations are performed using a generalized form of the recently developed method for quantum state tomography in spin 3/2 systems. By doing so, the possibility of controlling relative phases of superimposed pseudo-pure states is demonstrated. In addition, many aspects of the effect of the quadrupolar evolution, occurring during the RF pulses, on the quantum operations performance are discussed. Most of the procedures presented can be easily adapted to describe selective pulses of higher spin systems (>3/2) and for spin 1/2 under J couplings.

3.
Radiol Res Pract ; 2015: 159815, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26640710

RESUMEN

Introduction. In acute stroke by occlusion of the proximal medial cerebral artery (MCA) or the distal internal carotid artery, intravenous thrombolysis is an established treatment. Another option is mechanical recanalization. It remains unclear if the combination of both methods poses an additional bleeding risk. The aim of this retrospective analysis is to determine the proportion of hemorrhagic infarctions and parenchymal hematomas. Methods. Inclusion criteria were an occlusion of the carotid T or proximal MCA treated with full dose thrombolysis and mechanical recanalization. 31 patients were selected. Devices used were Trevo, Penumbra Aspiration system, Penumbra 3D Retriever, and Revive. The initial control by computed tomography was carried out with a mean delay to intervention of 10.9 hours (SD: 8.5 hours). Results. A slight hemorrhagic infarction (HI1) was observed in 2/31 patients, and a more severe HI2 occurred in two cases. A smaller parenchymal hematoma (PH1) was not seen and a space-occupying PH2 was seen in 2/31 cases. There was no significant difference in the probability of intracranial bleeding after successful (thrombolysis in cerebral infarctions 2b and 3) or unsuccessful recanalization. Conclusion. The proportion of intracranial bleeding using mechanical recanalization following intravenous thrombolysis appears comparable with reports using thrombolysis alone.

4.
Med Phys ; 10(6): 846-55, 1983.
Artículo en Inglés | MEDLINE | ID: mdl-6361507

RESUMEN

A fourth-generation scanner has been modified to perform prospectively gated cardiac computed tomography (CT). A computer program monitors the electrocardiogram (ECG) and predicts when to initiate the next scan in a gated series in order to acquire all projection data for a desired phase of the heart cycle. The system has been tested with dogs and has produced cross-sectional images of all phases of the cardiac cycle. Eight to ten scans per series were sufficient to obtain reproducible images of each transverse section in the end-diastolic and end-systolic phases. The radiation dose to the skin was approximately 1.4 cGy per scan. The prospectively gated system is more than twice as efficient as a retrospectively gated system in obtaining complete angular projection data for a 10% heart cycle window. A temporal smoothing technique to suppress reconstruction artifacts due to sorting inconsistent projection data was developed and evaluated. Image noise was reduced by averaging together any overlapping projection data. Prospectively gated cardiac CT has also been used to demonstrate that the error in attenuation measured with a single nongated CT scan through the heart can be as large as 50-60 CT numbers outside the heart in the lung field.


Asunto(s)
Corazón/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Animales , Perros , Electrocardiografía , Modelos Estructurales , Técnica de Sustracción , Tomografía Computarizada por Rayos X/instrumentación
5.
AJNR Am J Neuroradiol ; 34(5): 1016-21, S1, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23306013

RESUMEN

Hemolytic uremic syndrome is a multisystem disorder that is caused by infection with Shiga-toxin-producing Escherichia coli. HUS affects mainly children and is rare among adults. This retrospective case series analyzes clinical signs and MR imaging findings of 11 adult patients with HUS associated nervous system involvement during the epidemic EHEC outbreak in northern Europe with its epicenter in Hamburg in May 2011. The most prevalent imaging finding was symmetric pointy vasogenic edema of the brain stem in the acute and subacute phases of the disease (n = 5). One patient exhibited additional symmetric mesiotemporal signal changes mimicking limbic encephalitis. Two patients developed subcortical patchy lesions, and 4 subjects did not present with any signal changes. Remarkably, territorial ischemia, signs of hemorrhage, or blood-brain barrier disruption have not been detected. While brain stem lesions were transient and normalized with clinical recovery, supratentorial lesions did not resolve completely at 2-month follow-up examination.


Asunto(s)
Edema Encefálico/patología , Encéfalo/patología , Síndrome Hemolítico-Urémico/patología , Imagen por Resonancia Magnética , Adulto , Edema Encefálico/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Femenino , Alemania/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Prevalencia
7.
Inorg Chem ; 44(2): 423-30, 2005 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-15651890

RESUMEN

Comprehension of short- and medium-range order of phosphate glasses is a topic of interest, due to the close relation between network structure and mechanical, thermal, and optical properties. In this work, the short-range structure of glasses (1 - x)Ca(PO(3))(2).xAl(PO(3))(3) with 0 < or = x < or = 0.47 was studied using solid-state nuclear magnetic resonance spectroscopy, Raman spectroscopy, density measurements, and differential scanning calorimetry. The bonding between a network modifier species, Al, and the network forming phosphate groups was probed using high-resolution nuclear magnetic resonance spectroscopy of (27)Al and (31)P. Changes in the compositional behavior of the density, glass transition temperature, PO(2) symmetric vibrations, and Al coordination number were verified at around x = 0.30. (31)P NMR spectra show the presence of phosphorus in Q(2) sites with nonbridging oxygens (NBOs) coordinated by Ca ions and also Q(2) sites with one NBO coordinated by Al (namely, Q(2)(1Al)). The changes in the properties as a function of x can be understood by considering the mean coordination number measured for Al and the formation of only Q(2) and Q(2)(1Al) species. It is possible to calculate that a network formed only by Q(2)(1Al) phosphates can just exist up to the upper limit of x = 0.48. Above this value, Q(2)(2Al) species should appear, imposing a major reorganization of the network. Above x = 0.30 the network undergoes a progressive reorganization to incorporate Al ions, maintaining the condition that only Q(2)(1Al) species are formed. These observations support the idea that bonding principles for cationic species inferred originally in binary phosphate glasses can also be extended to ternary systems.

8.
Radiology ; 122(3): 781-6, 1977 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-841071

RESUMEN

A composite curve of biparietal diameters at various gestational ages was constructed from previous reports from five large centers. Estimates of the mean gestational age using the composite curve compared favorably with other reporting institutions. This suggests that the newly established echography department may employ the composite curve of mean values and need not develop its own biparietal growth curve. The clinical application of these mean values however, should recognize a considerable variance from the mean. These variations represent normal growth differences in the biparietal dimension, errors inherent in the ultrasonic methodology and apparent differences in the populations examined. A method is suggested by which variations from the mean may be identified for each echographic facility.


Asunto(s)
Edad Gestacional , Hueso Parietal/anatomía & histología , Ultrasonido , Cefalometría , Humanos
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