Doppler ultrasound and giant cell arteritis

ObjectiveTo evaluate the utility of ultrasound in aiding the diagnosis of giant cell arteritis (GCA), in monitoring the response to corticotherapy, and in detecting early relapses.MethodsA pilot study, prospective, included 10 patients with suspected GCA. All patients underwent ultrasound examination of both temporal arteries before temporal artery biopsy (TAB), 3 weeks after starting treatment, and 3 months after diagnosis. For this study, the histological findings alone were used to define if patients were suffering from GCA. The findings on ultrasound were compared with the results of biopsy. The best place to perform TAB was observed by ultrasound.ResultsAll patients with positive biopsy were detected with ultrasound. No false positives were observed on ultrasound. The results presented give a sensibility, specificity, and positive predictive value of 100% for the use of ultrasound in the diagnosis of GCA. Two relapses were detected early by ultrasound during the follow-up.ConclusionsThis pilot study suggests that eco-doppler may be a useful tool in diagnosis and clinic follow-up in patients with suspected GCA

Design and Validation of an FPGA-Based Configurable Transcranial Doppler Neurofeedback System for Chronic Pain Patients

Neurofeedback is a self-regulation technique that can be applied to learn to voluntarily control cerebral activity in specific brain regions. In this work, a Transcranial Doppler-based configurable neurofeedback system is proposed and described. The hardware configuration is based on the Red Pitaya board, which gives great flexibility and processing power to the system. The parameter to be trained can be selected between several temporal, spectral, or complexity features from the cerebral blood flow velocity signal in different vessels. As previous studies have found alterations in these parameters in chronic pain patients, the system could be applied to help them to voluntarily control these parameters. Two protocols based on different temporal lengths of the training periods have been proposed and tested with six healthy subjects that were randomly assigned to one of the protocols at the beginning of the procedure. For the purposes of the testing, the trained parameter was the mean cerebral blood flow velocity in the aggregated data from the two anterior cerebral arteries. Results show that, using the proposed neurofeedback system, the two groups of healthy volunteers can learn to self-regulate a parameter from their brain activity in a reduced number of training sessions.This research was funded by Ministerio de Economía y Competitividad, Spain, grant number PSI2013-48260-C3-2-R. The APC was funded by Ministerio de Economía y Competitividad, Spain, grant number PSI2013-48260-C3-2-R

Doppler ultrasound and giant cell arteritis

Ana Marina Suelves1, Enrique España-Gregori1,2, Jose Tembl3, Stephanie Rohrweck1, Jose Maria Millán4, Manuel Díaz-Llopis1,4,51Service of Ophthalmology, La Fe University Hospital, Valencia, Spain; 2Department of Optics, University of Valencia, Valencia, Spain; 3Service of Neurology, La Fe University Hospital, Valencia, Spain; 4CIBERER, Ciber de Enfermedades Raras, Valencia, Spain; 5Faculty of Medicine, University of Valencia, Valencia, SpainObjective: To evaluate the utility of ultrasound in aiding the diagnosis of giant cell arteritis (GCA), in monitoring the response to corticotherapy, and in detecting early relapses.Methods: A pilot study, prospective, included 10 patients with suspected GCA. All patients underwent ultrasound examination of both temporal arteries before temporal artery biopsy (TAB), 3 weeks after starting treatment, and 3 months after diagnosis. For this study, the histological findings alone were used to define if patients were suffering from GCA. The findings on ultrasound were compared with the results of biopsy. The best place to perform TAB was observed by ultrasound.Results: All patients with positive biopsy were detected with ultrasound. No false positives were observed on ultrasound. The results presented give a sensibility, specificity, and positive predictive value of 100% for the use of ultrasound in the diagnosis of GCA. Two relapses were detected early by ultrasound during the follow-up.Conclusions: This pilot study suggests that eco-doppler may be a useful tool in diagnosis and clinic follow-up in patients with suspected GCA.Keywords: giant cell arteritis, ultrasound, temporal artery biopsy, optic nerv

Analyzing Neural Correlates of Attentional Changes during the Exposure to Virtual Environments: Application of Transcranial Doppler Monitoring

[EN] Transcranial Doppler monitoring (TCD) has been proposed as a tool to be used in Augmented Cognition (AugCog) systems to monitor brain activation during the performance of different cognitive tasks. In the present study, the main goal is to analyze variations in blood flow velocity (BFV) measured by TCD during the exposure to a virtual reality environment when there are changes in the focus of attention of the participants. Two abrupt events are forced during the navigation in a virtual environment in order to change their focus of attention to the real world. In one of them, the screen goes completely blue, and in the other one, a mesh appears in front of the virtual environment making it difficult to visualize. Results show that BFV values in both middle cerebral arteries remain similar when the first event occurs, but there is an increase during the second event. The origin of this increment may probably be found in the higher difficulty of having a mesh in front of the virtual environment, requiring more attention than before. These results show that changes in the stimuli can generate modifications in BFV that can be monitored by TCD, and can be useful for AugCog applications.Rey, B.; Parkhutik, V.; Tembl, J.; Alcañiz Raya, ML. (2011). Analyzing Neural Correlates of Attentional Changes during the Exposure to Virtual Environments: Application of Transcranial Doppler Monitoring. Lecture Notes in Computer Science. 6780:212-220. doi:10.1007/978-3-642-21852-1_27S2122206780Aaslid, R., Markwalder, T.M., Nornes, H.: Noninvasive Transcranial Doppler Ultrasound Recording of Flow Velocity in Basal Cerebral Arteries. J. Neurosurg. 57, 76–774 (1982);Smith, T.F., Waterman, M.S.: Identification of Common Molecular Subsequences. J. Mol. Biol. 147, 195–197 (1981)Iadecola, C.: Regulation of the Cerebral Microcirculation during Neural Activity: Is Nitric Oxide the Missing Link? Trends Neurosci. 16, 206–214 (1993)Risberg, J.: Regional cerebral blood flow in neuropsychology. Neuropsychologia 24, 135–140 (1986)Daffertshofer, M.: Functional Doppler testing. In: Hennerici, M., Meairs, S. (eds.) Cerebrovascular ultrasound, pp. 341–359. Cambridge University Press, Cambridge (2001)Stroobant, N., Vingerhoets, G.: Transcranial Doppler Ultrasonography Monitoring of Cerebral Hemodynamics during Performance of Cognitive Tasks: A Review. Neuropsychol. Rev. 10, 213–231 (2000)Duschek, S., Schandry, R.: Functional Transcranial Doppler sonography as a Tool in Psychophysiological Research. Psychophysiology 40, 436–454 (2003)Warm, J.S., Matthews, G., Tripp, L., Hancock, P.A.: Cerebral Hemodynamics and Brain Systems in Vigilance. In: Schmorrow, D.D. (ed.) Foundations of Augmented Cognition, pp. 707–708. Lawrence Erlbaum Associates, Mahwah (2005)Warm, J.S., Parasuraman, R.: Cerebral Hemodynamics and Vigilance. In: Parasuraman, R., Rizzo, M. (eds.) Neuroergonomics. The Brain at Work, pp. 146–158. Oxford University Press, New York (2007)Schnittger, C., Sönke, J., Anouschen, A., Münte, T.F.: Relation of Cerebral Blood Flow Velocity and Level of Vigilance in Humans. Cognitive Neurosci. and Neuropsychol. 8, 1637–1639 (1997)Helton, W.S., Hollander, T.D., Warm, J.S., Tripp, L.D., Parsons, K., Matthews, G., Dember, W.N., Parasuraman, R., Hancock, P.A.: The abbreviated vigilance task and cerebral hemodynamics. J. Clin. and Exp. Neuropsychol. 29, 545–552 (2007)Hitchcock, E.M., Warm, J.S., Matthews, G., Dember, W.N., Shear, P.K., Tripp, L.D., Mayleben, D.W., Parasuraman, R.: Automation Cueing Modulates Cerebral Blood Flow and Vigilance in a Simulated Air Traffic Control Task. Theor. Issues in Ergon. Sci. 4, 89–112 (2003)Rey, B., Alcañiz, M., Naranjo, V., Tembl, J., Parkhutik, V.: Transcranial Doppler: A Tool for Augmented Cognition in Virtual Environments. In: Schmorrow, D.D., Estabrooke, I.V., Grootjen, M. (eds.) FAC 2009. LNCS, vol. 5638, pp. 427–436. Springer, Heidelberg (2009)Alcañiz, M., Rey, B., Tembl, J., Parkhutik, V.: A Neuroscience Approach to Virtual Reality Experience Using Transcranial Doppler Monitoring. Presence, Teleoperators & Virtual Environments 18(2), 97–111 (2009)Rey, B., Alcañiz, M., Tembl, J., Parkhutik, V.: Brain Activity and Presence: a Preliminary Study in Different Immersive Conditions using Transcranial Doppler Monitoring. Virtual Reality 14(1), 55–65 (2010)Slater, M., Brogni, A., Steed, A.: Physiological responses to breaks in presence: A pilot study. In: Proceedings of the 6th Annual International Workshop on Presence (2003)Slater, M., Steed, A.: A virtual presence counter. Presence: Teleoperators & Virtual Environments 9, 413–434 (2000)Garau, M., Friedman, D., Widenfeld, H.R., Antley, A., Brogni, A., Slater, M.: Temporal and spatial variations in presence: Qualitative analysis of interviews from an experiment on breaks in presence. Presence: Teleoperators & Virtual Environments 17, 293–309 (2008)Slater, M., Guger, C., Edlinger, G., Leeb, R., Pfurtscheller, G., Antley, A., Garau, M., Brogni, A., Friedman, D.: Analysis of physiological responses to a social situation in an immersive virtual environment. Presence: Teleoperators & Virtual Environments 15, 553–569Ringelstein, E.B., Kahlscheuer, B., Niggemeyer, E., Otis, S.M.: Transcranial Doppler sonography: Anatomical landmarks and normal velocity values. Ultrasound in Medicine and Biology 16, 745–761 (1990)Sitzer, M., Diehl, R.R., Hennrici, M.: Visually evoked cerebral blood flow responses: Normal and pathological conditions. J Neuroimaging 2, 65–70 (1992)Angevine, J.B., Cotman, C.W.: Principles of neuroanatomy. Oxford University Press, New York (1999)Holden, M.K., Todorov, E.: Use of virtual environments in motor learning and rehabilitation. In: Stanney, K.M. (ed.) Handbook of Virtual Environments: Design, Implementation, and Applications, pp. 999–1026. Lawrence Erlbaum Assocaites, Mahwah (2002)Kelley, R.E., Chang, J.Y., Scheinman, N.J., Levin, B.E., Duncan, R.C., Lee, S.C.: Transcranial Doppler assessment of cerebral flow velocity during cognitive tasks. Stroke 23, 9–14 (1992)Vingerhoets, G., Stroobant, N.: Lateralization of cerebral blood flow velocity changes during cognitive tasks: A simultaneous bilateral transcranial Doppler study. Stroke 30, 2152–215

Quantitative Signal Intensity in Fluid-Attenuated Inversion Recovery and Treatment Effect in the WAKE-UP Trial

International audienceBackground and Purpose— Relative signal intensity of acute ischemic stroke lesions in fluid-attenuated inversion recovery (fluid-attenuated inversion recovery relative signal intensity [FLAIR-rSI]) magnetic resonance imaging is associated with time elapsed since stroke onset with higher intensities signifying longer time intervals. In the randomized controlled WAKE-UP trial (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke Trial), intravenous alteplase was effective in patients with unknown onset stroke selected by visual assessment of diffusion weighted imaging fluid-attenuated inversion recovery mismatch, that is, in those with no marked fluid-attenuated inversion recovery hyperintensity in the region of the acute diffusion weighted imaging lesion. In this post hoc analysis, we investigated whether quantitatively measured FLAIR-rSI modifies treatment effect of intravenous alteplase. Methods— FLAIR-rSI of stroke lesions was measured relative to signal intensity in a mirrored region in the contralesional hemisphere. The relationship between FLAIR-rSI and treatment effect on functional outcome assessed by the modified Rankin Scale (mRS) after 90 days was analyzed by binary logistic regression using different end points, that is, favorable outcome defined as mRS score of 0 to 1, independent outcome defined as mRS score of 0 to 2, ordinal analysis of mRS scores (shift analysis). All models were adjusted for National Institutes of Health Stroke Scale at symptom onset and stroke lesion volume. Results— FLAIR-rSI was successfully quantified in stroke lesions in 433 patients (86% of 503 patients included in WAKE-UP). Mean FLAIR-rSI was 1.06 (SD, 0.09). Interaction of FLAIR-rSI and treatment effect was not significant for mRS score of 0 to 1 ( P =0.169) and shift analysis ( P =0.086) but reached significance for mRS score of 0 to 2 ( P =0.004). We observed a smooth continuing trend of decreasing treatment effects in relation to clinical end points with increasing FLAIR-rSI. Conclusions— In patients in whom no marked parenchymal fluid-attenuated inversion recovery hyperintensity was detected by visual judgement in the WAKE-UP trial, higher FLAIR-rSI of diffusion weighted imaging lesions was associated with decreased treatment effects of intravenous thrombolysis. This parallels the known association of treatment effect and elapsing time of stroke onset