Hemodynamic Changes in the Treatment of Multiple Intracranial Aneurysms: A Computational Fluid Dynamics Study.

BACKGROUND: Intracranial aneurysm rupture is associated with a high mortality and disability despite modern medical care. Multiple aneurysms occur in nearly 16% of patients, and imaging studies of naturally occurring multiple aneurysms are valuable for computational fluid dynamics studies. In this study, we describe and analyze the hemodynamic changes produced in a distal aneurysm after the treatment of a proximal aneurysm. METHODS: Between January 2008 and December 2017, 24 cases of multiple intracranial aneurysms of the same vascular tree were treated in our center. Full carotid segmentations from digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography were obtained, and transient pulsatile simulations were performed using computational fluid dynamics software. Output variables included maximum peak systole wall shear stress (WSS), minimum mid-diastolic WSS, maximum systolic pressure, low shear area, and high shear area both before and after treatment of the proximal aneurysm. RESULTS: The mean size of ruptured and unruptured aneurysms was 7.05 and 5.23 mm, respectively (P = 0.035), with respective aspect ratios of 1.22 and 2.04 (P = 0.001). Maximum peak systole WSS was lower and minimum mid-diastolic WSS was higher in unruptured aneurysms (P = 0.04 and 0.034, respectively). After treatment of the proximal aneurysm, low shear area in the distal aneurysm increased from 54.15% to 56.93% (P = 0.02). The opposite effect is noted in aneurysms with an interaneurysmal distance <10 mm. Posttreatment peak systole pressure was also increased significantly (P = 0.03). CONCLUSIONS: The hemodynamic changes in a distal aneurysm after treatment of a proximal aneurysm showed an unfavorable profile associated with an increased theoretical risk of bleeding.

Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center.

BACKGROUND: Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors. METHODS: From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score. RESULTS: Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P < 0.05), ruptured status and previous embolization were not related to rate of obliteration, and low-grade AVMs had higher obliteration rates. Posttreatment hemorrhage incidence was 8.72%; nidus diameter was the only predictor (P = 0.05). Symptomatic radiation-induced changes occurred in 11.79% of patients and were significantly associated with unruptured status (P < 0.05). Treatment success as a composite measure was obtained in 70.77% of patients. Receiver operating characteristic curves were presented for each scoring system and outcome measure; best area under the curve was 0.687 for Lawton combined score in the obliteration outcome. CONCLUSIONS: In the long-term, linear accelerator-based radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs.

Técnicas de radiodiagnóstico en tumores neuroendocrinos gastroenteropancreáticos / Radiodiagnostic techniques in gastroenteropathic neuroendocrine tumors

Los avances tecnológicos en tomografía computarizada y resonancia magnética han permitido que estas técnicas jueguen un papel cada vez más importante en el manejo de los pacientes con tumores neuroendocrinos que, por otro lado, siguen siendo un reto incluso para radiólogos con gran experiencia en estas neoplasias fascinantes, como demuestran las diferentes series publicadas. El desarrollo de la tomografía computarizada multidetector ha mejorado la sensibilidad en la detección de los tumores de islotes pancreáticos, así como los elevados gradientes y otros avances en resonancia magnética. Ambas técnicas parecen tener una sensibilidad similar pero la comparación es difícil entre las distintas modalidades de imagen y los diferentes modos o estadios del desarrollo tumoral. En tumores carcinoides, tanto la tomografía computarizada como la resonancia magnética son importantes a la hora de definir la extensión de la enfermedad metastásica y evaluar la respuesta al tratamiento. Ambas técnicas, junto con la ecografía endoscópica, pueden ser críticas a la hora de localizar la fuente de un tumor pancreático endocrino funcionante. Los resultados están en relación directa con la experiencia y el interés del radiólogo, la meticulosidad en la técnica y la resolución de los distintos métodos de imagen. Sin embargo, la mayoría de las veces se necesita una combinación de varias pruebas de localización anatómica con estudios de localización funcional y con radioisótopos para encontrar estas escurridizas lesiones (AU)

Because of the technical advances made in computed tomography (CT) and magnetic resonance imaging (MRI), these techniques have become increasingly important in the management of patients with neuroendocrine tumors which, as shown by several published series, continue to pose a challenge even for radiologists highly experienced in these fascinating neoplasms. The development of multidetector CT, as well as high-gradient MRI and other advances in this modality, have improved the sensitivity of pancreatic islet tumor detection. The sensitivity of the two techniques seems to be similar, but comparison between the distinct imaging modalities and the different modes or stages of tumoral development is difficult. In carcinoid tumors, both CT and MRI are important to define the extension of metastatic disease and to evaluate treatment response. Both techniques, together with endoscopic ultrasonography, can be essential when identifying the source of a functioning pancreatic endocrine tumor. The results are directly related to the radiologist’s interest and experience, the meticulousness with which the technique is performed, and the resolution of the distinct imaging methods. However, a combination of various techniques including functional localization and radioisotope use is usually required to detect these elusive lesions (AU)

Herniación transdural idiopática de la médula espinal. A propósito de un caso y revisión de la bibliografía / Idiopathic transdural spinal cord herniation: a case report and review of the literature

La herniación transdural idiopática de la médula espinal es una entidad poco frecuente que cursa generalmente con síndrome de BrownSequard que consiste en parálisis ipsilateral y pérdida de la sensibilidad al dolor y a la temperatura contralateral. Los hallazgos radiológicos (Mielo-TC y RM) son muy típicos, con angulación y desplazamiento anterolateral de la médula. Típicamente afecta a pacientes adultos de edad media y el tratamiento es la cirugía. Nosotros presentamos una paciente con clínica de Brown-Sequard y signos radiológicos típicos de herniación transdural de la médula espinal. El reconocimiento de esta enfermedad es importante, ya que la reparación quirúrgica del defecto dural conduce a una mejoría de los síntomas neurológicos (AU)