ABSTRACT
Introducción: La angiografía carotídea se utiliza para confi rmar la presencia de estenosis de la bifurcación carotídea (BC). Sin embargo, dado que este método resulta invasivo y presenta cierta morbimortalidad, existe un creciente interés en los métodos no invasivos, como la angiografía por resonancia magnética con gadolinio (ARM-Gd) y la ecografía Doppler color (EDC). El objetivo de este trabajo es determinar la correlación que existe entre la ecografía Doppler color y la angiografía por resonancia magnética con gadolinio en la determinación del grado de estenosis. Materiales y métodos: Se analizaron por ecografía Doppler color y angiografía por resonancia magnética con gadolinio 100 estudios de la bifurcación carotídea, realizados entre enero de 2009 y agosto de 2011 en el Sanatorio Allende. Se determinó el coefi ciente de concordancia Kappa, evaluando por ecografía Doppler color el porcentaje de estenosis carotídea según la reducción del diámetro y la velocidad sistólica máxima (VSM) y por angiografía por resonancia magnética con gadolinio la reducción de la luz visualizada. En ambos métodos se empleó el criterio de NASCET. También se analizó la superfi cie de la placa. Resultados: Se obtuvo una muy buena correlación entre la ecografía Doppler color y la angiografía por resonancia magnética con gadolinio, con un coefi ciente de concordancia Kappa de 0,90 y un intervalo de confi anza (IC) de 95% (0,786-0,99). Sin embargo, existió una discordancia para valoar la superfi cie de la placa, que dejó en evidencia la superioridad de la angiografía por resonancia magnética con gadolinio para defi nir la superfi cie irregular y/o ulcerada. Conclusión: El avance de la tecnología y el creciente número de estudios que demuestran la fi abilidad y correlación diagnóstica de los métodos no invasivos hacen suponer que en un corto plazo estos reemplazarán a la angiografía en el diagnóstico y valoración de la patología carotídea.
Introduction: Carotid angiography is used to confi rm carotid bifurcation (CB) stenosis. However, it is an invasive method that involves some morbidity. For this reason there is growing interest in non-invasive methods for the evaluation of carotid stenosis, including magnetic resonance angiography with gadolinium (MRAG) and color Doppler ultrasound (USDC). The aim of this study is to determine the correlation between the color Doppler ultrasound and magnetic resonance angiography with gadolinium in the evaluation of the degree of stenosis. Materials and methods: One hundred carotid bifurcations were studied by color Doppler ultrasound and magnetic resonance angiography with gadolinium between January 2009 and August 2011 in Sanatorio Allende. The level of agreement was determined using the Kappa coeffi cient, analyzing the percentage of carotid stenosis with color Doppler ultrasound according to the maximum systolic speed and the stenosis seen by magnetic resonance angiography with gadolinium, using the NASCET criteria for both methods. Results: An excellent correlation was obtained between Doppler ultrasound and magnetic resonance angiography with gadolinium, with a Kappa coeffi cient of 0.90 (95% CI: 0.786-0.99). There was disagreement between the two methods in assessing the plaque surface, showing that magnetic resonance angiography with gadolinium was better for detecting an irregular surface and / or ulcerated plaque. Conclusion: The technological improvement and the increase in reliable studies that have a good diagnostic correlation with non-invasive methods, it could be assumed that, in a short period of time, Doppler ultrasound will gradually replace angiography in the diagnosis of carotid pathology.
ABSTRACT
OBJECTIVE: This study aims to compare outcomes of active management of monochorionic diamniotic twin pregnancies complicated with severe intrauterine growth restriction (IUGR) of one twin before 24 weeks with continuous or intermittent absent or reversed end-diastolic flow (AREDF) in the umbilical artery, with or without twin-to-twin transfusion syndrome (TTTS). METHOD: This study is a retrospective comparison of 45 consecutive cases of severe selective IUGR (s-IUGR) defined as an estimated fetal weight at or below the fifth centile with a >25% weight discordance and AREDF in the umbilical artery before 24 weeks and 166 consecutive cases of TTTS stage III, with AREDF in the donor (TTTS3D) and also with s-IUGR. These were treated by either selective laser photocoagulation of chorionic vessels (SLPCV) or cord coagulation (CC). RESULTS: The 166 cases of TTTS3D were treated by SLPCV, whereas 23 and 22 cases of s-IUGR were treated by SLPCV and CC, respectively. Overall survival was 52.17% or 45.45% in s-IUGR treated by SLPCV or CC, respectively, and 48.49% in TTTS3D. The survival of appropriately grown for gestational age (AGA) twins following CC (90.9%) was higher than that following SLPCV in s-IUGR (74%) or in recipient twins of TTTS3D (55.42%) (p = 0.001). Survival of the IUGR twin was 30% and 41.56% with SLPCV in s-IUGR and TTTS3D, respectively. CONCLUSIONS: Active management of severe IUGR with AREDF in the umbilical artery seems beneficial. Survival rates with SLPCV were similar in s-IUGR and TTTS3D. However, there was a trend for higher survival rates in the AGA twin for CC. The choice of the technique should be driven by objective counseling on survival of both IUGR and AGA twins and therefore by the utility-based ethical values expressed by the pregnant woman.
Subject(s)
Fetal Growth Retardation/mortality , Fetofetal Transfusion/mortality , Pregnancy, Twin , Adult , Female , Fetal Growth Retardation/diagnostic imaging , Fetal Growth Retardation/etiology , Fetal Growth Retardation/surgery , Fetofetal Transfusion/diagnostic imaging , Fetofetal Transfusion/surgery , Humans , Laser Coagulation , Pregnancy , Pregnancy Trimester, Second , Retrospective Studies , Survival Rate , Twins, Monozygotic , UltrasonographyABSTRACT
We introduce a simple approach for the efficient generation of tunable narrow-bandwidth picosecond pulses synchronized to broadband femtosecond ones. Second harmonic generation in the presence of large group velocity mismatch between the interacting pulses transfers a large fraction of the energy of a broadband fundamental frequency pulse into a narrowband second harmonic one. Using a periodically poled stoichiometric lithium tantalate crystal coupled to an infrared optical parametric amplifier, we generated 200-nJ pulses with spectral width lower than 8.5 cm(-1) and tunability from 720 to 890 nm. Energy scaling and extension of the tuning range are straightforward.
