Submitted by Eunice Novais (enovais@uepg.br) on 2018-08-30T17:43:30Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Claudiane Ayres P.pdf: 1202728 bytes, checksum: 2b48ec7440eb9f77288374dd442bfe90 (MD5) / Made available in DSpace on 2018-08-30T17:43:30Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Claudiane Ayres P.pdf: 1202728 bytes, checksum: 2b48ec7440eb9f77288374dd442bfe90 (MD5) Previous issue date: 2018-02-27 / A pressão intracraniana (PIC) tem variações determinadas pelos ciclos respiratórios e cardíacos, portanto, acredita-se que lesões cardiovasculares podem ocasionar modificações na PIC. As doenças cardiovasculares (DCVs) estão dentre as principais causas de morte nos países desenvolvidos e em desenvolvimento e frequentemente, para o seu tratamento, torna-se necessário a realização de cirurgia cardíaca. Porém, pacientes submetidos a tais procedimentos desenvolvem complicações relacionadas a disfunções cardiopulmonares. A fim de minimizar as complicações decorrentes da cirurgia, a fisioterapia, como parte da reabilitação cardiopulmonar é capaz de controlar os sintomas respiratórios e melhorar a função cardiovascular, atuando através de exercícios aeróbicos e respiratórios. Este trabalho teve como objetivo monitorar a PIC, a força muscular respiratória e os sinais vitais de pacientes pré- e pós- cirurgia cardíaca e comparar os efeitos de dois protocolos de fisioterapia na recuperação da força muscular respiratória. Participaram do estudo 48 pacientes. Observou-se que as DCVs podem alterar a PIC de pacientes acometidos por tais patologias. Independente do protocolo utilizado, a realização da fisioterapia como parte da reabilitação cardiorrespiratória é benéfica para a recuperação cardiopulmonar dos pacientes submetidos à cirurgia cardíaca. / Intracranial pressure (ICP) has variations determined by respiratory and cardiac cycles, therefore, it is believed that cardiovascular lesions may cause changes in ICP. Cardiovascular diseases (CVDs) are among the leading causes of death in developed and developing countries, and it is often necessary to perform cardiac surgery for their treatment. However, patients submitted to such procedures develop complications related to cardiopulmonary dysfunctions. In order to minimize the complications resulting from surgery, physical therapy as part of cardiopulmonary rehabilitation is able to control respiratory symptoms and improve cardiovascular function by acting through aerobic and respiratory exercises. The objective of this study was to monitor ICP, respiratory muscle strength and vital signs of pre- and post-cardiac surgery patients, and to compare the effects of two physiotherapy protocols on respiratory muscle strength recovery. 48 patients participated in the study. It has been observed that CVDs can alter ICP in patients affected by such pathologies. Regardless of the protocol used, the performance of physiotherapy as part of cardiorespiratory rehabilitation is beneficial for the cardiopulmonary recovery of patients undergoing cardiac surgery.

Introdução: A alta incidência de oclusão incompleta e recanalização dos aneurismas intracranianos de colo largo tratados por via endovascular levaram ao desenvolvimento de novas técnicas, entre elas o uso do Onyx ®. Objetivos: avaliar a eficiência do agente embólico líquido Onyx® em produzir oclusão completa dos aneurismas intracranianos de colo largo e avaliar a estabilidade do tratamento aos 6 meses e aos 18 meses, por meio de controles angiográficos. Casuística e métodos: Esta tese foi realizada na Seção de Neuroradiologia Intervencionista da Med Imagem, do Hospital São Joaquim da Real e Benemérita Associação Portuguesa de Beneficência de São Paulo, através da revisão de dados clínicos e radiológicos de 69 pacientes tratados pelo autor, com 84 aneurismas intracranianos de colo largo no período de julho de 2002 a fevereiro de 2006. Dez pacientes eram do sexo masculino e 59 do sexo feminino, com idade variando de 24 anos a 86 anos (mediana de 52 anos). Todos os aneurismas tinham origem lateral à artéria e apresentavam pelo menos um dos critérios usados para definir colo largo - colo maior que 4 mm de diâmetro e relação saco/colo menor que 1,5. Cinqüenta aneurismas eram pequenos, 30 grandes e quatro gigantes (diâmetro máximo menor que 12mm, de 12mm a 25mm e maiores que 25mm, respectivamente). As apresentações clínicas mais comuns foram: achado incidental em 34 pacientes, pós-hemorragia sub aracnóide e recanalização após tratamento com espirais destacáveis em 10. A maioria dos aneurismas era da artéria carótida interna (76 aneurismas). Controles angiográficos foram feitos ao final, aos seis meses e aos 18 meses do tratamento (controles I, II e III respectivamente), sendo analisados principalmente o grau de oclusão (completa ou incompleta), incidência de recanalização e complicações clínicas. Avaliação estatística foi feita pelo método de Kaplan-Meier para o percentual cumulativo de oclusão completa e percentual de recanalização e análise univariada e multivariada dos fatores preditivos de oclusão total imediata e tardia através de regressão logística. Resultados: O índice de oclusão completa foi de 65,5%, 84,6% e de 90,3% para todos os aneurismas, nos controles I, II e III respectivamente. Estes índices foram de 74%, 95,1% e de 95,2% para os aneurismas pequenos e de 53,3%, 70% e de 80% para os aneurismas grandes nos controles I, II e III respectivamente. Oclusão completa ocorreu em 50% dos aneurismas gigantes nos controles I e II, sem haver controle III neste grupo. Recanalização ocorreu em 3 aneurismas (4,6%). O porcentual cumulativo de oclusão completa foi de 97,63% (IC de 95% variando de 95,27 a 100) para os aneurismas pequenos aos 9 meses e de 83,86% (IC de 95% variando de 67,73 a 100) para os aneurismas grandes aos 21 meses. Três pacientes faleceram (4,3%), havendo relação com o procedimento em dois (2,9%). Morbidade permanente ocorreu em cinco pacientes (7,2%), sendo incapacitante em um (1,4%). Conclusões: 1. O uso do Onyx® foi eficiente na oclusão completa dos aneurismas intracranianos de colo largo. 2. O tratamento foi estável nos controles angiográficos aos 6 meses e aos 18 meses. / Introduction: The high rate of incomplete occlusion and intracranial large neck aneurysms recanalization lead to the development of new techniques, including the use of Onyx®. Purpose: to evaluate the efficacy of the liquid embolic system Onyx ® to produce completes occlusion of the intracranial large neck aneurysms and evaluates the stability of the treatment at 6 month and 18 month angiographic control. Materials and Methods: this thesis has been performed at Section of Interventional Neuroradiology of Med Imagem, at the Hospital São Joaquim da Real e Benemérita Associação Portuguesa de Beneficência de São Paulo, based on a review of clinical and radiological records of 69 patients treated by the author, harboring 84 large neck intracranial aneurysms between July 2002 and February 2006. Ten patients were male and 59 female, with age ranging from 24 to 86 years old. All aneurysms were lateral to the parent vessel and were wide neck (neck > 4 mm and/or domus to neck ratio < 1.5). Fifty aneurysms were small (<12 mm), 30 were large (12 to 25 mm) and 4 were giant (> 25 mm). Thirty four aneurysms were incidental, 10 were ruptured and 10 were recanalized after coil treatment and the majority was located in the internal carotid artery (76). Angiographic follow-up was done at the end of the procedure, at six month and at 18 month (controls I, II and III respectively), analyzing the rate of complete occlusion, recanalization and clinical complication. Statically analysis were done by Kaplan-Meier method for cumulative percentage of complete aneurysm occlusion and for recanalization, and univariate and multivariate analysis of predictive factors of immediate and late complete occlusion through logistic regression. Results: Complete aneurysm occlusion was achieved in 65.5% on immediate control, in 84.6% at 6 month, and in 90.3% at 18 month follow-up periods for all aneurysms. This rate was 74%, 95.1% and 95.2% for small and 53.3%, 70% and 80% for large aneurysms at the same follow-up periods. In the giant aneurysm group, two had complete and stable occlusion at six month follow-up angiography. Recanalization was seen in three aneurysms (4,6%). Kaplan Meyer\'s cumulative percentage of complete aneurysm occlusion was 97.63% (CI 95% ranging from 95,27 to 100) for small aneurysms at 9 months and 83.86% (CI 95% ranging from 67,73 to 100) for large aneurysms at 21 months. There were three deaths (4,3%), two procedure-related (2.9%). Overall morbidity was 7.2%, being disabling in one (1,4%). Conclusions: 1. The use of Onyx was efficient in the complete occlusion of wide neck intracranial aneurysms. 2. The treatment was stable at 6 month and 18 month angiographic controls.

Early deterioration and long-term recurrence were common after stroke or transient ischemic attach (TIA), however, it is unclear whether they were correlated with active embolization and the consequent new cerebral infarct in acute phase. By employing TCD and diffusion weighted imaging (DWI), we studied the significance of the progression of MES and infarcts during acute phase on the clinical outcomes. We found that the disappearance of MES was correlated with better improvement on day 7 of recruitment; for the long-term outcome, occurrence of exacerbating infarct tended to predict recurrent stroke. Treatment aiming to reduce MES and prevent infarct exacerbation in acute phase may improve the prognosis after stroke. / Finally, one study was performed to assess the changes of hemodynamic parameters after stenting of severe stenosis in the MCA. We aimed to investigate whether TCD can reflect the lumen changes after revascularization and detect hyperperfusion. The findings showed that the velocity of stented MCA in most patients normalized within 24 hours after procedure, but the role of TCD in detecting restenosis in long run needed to be verified; no one suffered from hyperperfusion during the period of our study. The long-term outcomes of patients with normalized velocity versus those with persistently high velocity needed to be further studied. Apart from the velocity changes, changes of the collateral flow after intervention may also be an important part of hemodynamic changes. (Abstract shortened by UMI.) / It was suggested that anti-platelet therapy can reduce the MES, but little was known about the efficacy of low molecular weight heparin (LMWH) although in theory LMWH can reduce the red fibrin-dependent thromboemboli. As a sub-analysis of Fraxiparine in Ischemic Stroke (FISS)-tris study, our study did not show advantages of LMWH in eliminating MES compared with aspirin. / Previous studies showed the accuracy of TCD in diagnosis of middle cerebral artery (MCA) stenosis was variable and the positive predictive value (PPV) was less than 50% in a recent report. One of the important reasons was that most criteria were based on the velocity-only method, ignoring other non-velocity information. Thus, we tried to establish new diagnostic criteria by means of designing an assessment form which integrated more characteristics apart from the velocity acceleration. A composite score for each MCA was calculated according to following parameters in the form: Velocity Scale (score 0-6 for peak systolic velocities&lt;140 to &ge;300cm/s), Hemodynamic Scale (score 0-5 for focal or diffuse velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), Spectrum Scale (score 0-2 for normal spectrum, turbulence and musical murmurs). Our results showed that compared with the previously reported criteria, the score calculated from the assessment form yielded much more balanced accuracy against magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). However, the composition of the assessment form was only based on personal experience and need to be further modified. Multicenter studies with large sample size are also needed to confirm the advantages of this new method. / Second, we performed three studies to investigate the relationship between the progression of MES and the short or long-term outcome and the relationship between MES and different treatments. / Hao, Qing. / Adviser: Ka Sing Wong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3419. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 155-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

OBJETIVO: Avaliar a capacidade do eletrorretinograma de padrão reverso (PERG) de campo total de detectar alterações funcionais da retina em olhos com papiledema resolvido de pacientes com a síndrome do pseudotumor cerebral (PTC). Utilizar a tomografia de coerência óptica de domínio Fourier (FD-OCT) para avaliar a espessura total e das camadas internas da retina (após segmentação dos dados) na área macular e a camada de fibras nervosas retinianas (CFNR) peripapilar em pacientes com PTC, e compará-las com aquelas de olhos normais. Estudar a correlação entre as amplitudes do PERG, as medidas da tomografia de coerência óptica (OCT) e a perda de campo visual (CV) avaliada pela perimetria computadorizada. MÉTODOS: Cinquenta e dois olhos com papiledema clinicamente resolvidos de 29 pacientes portadores de PTC foram submetidos a exame oftalmológico completo, CV, PERG e OCT. As seguintes medidas obtidas pelo OCT foram analisadas: a espessura da CFNR peripapilar, a espessura macular total (EMT), avaliada em oito setores, de acordo com o mapa do Early Treatment Diabetes Retinopathy Study, e medidas segmentadas na região da mácula da CFNR, da camada de células ganglionares (CCG) e da camada nuclear interna (CNI). Os resultados do CV foram avaliados, levando em consideração o mean deviation (MD) e os valores de diferentes regiões do CV divididos, de acordo com sua correspondência no nervo óptico, seguindo o mapa de Garway-Heath. Foram, também, calculados os desvios médios de 12 ou de 16 pontos centrais do CV, que estimulam áreas semelhantes àquelas avaliada pelo OCT macular e pelo PERG. Os achados foram comparados utilizando-se as equações de estimativas generalizadas para compensação da interdependência dos dois olhos de um mesmo indivíduo. Foram, também, calculadas e comparadas as áreas sob as curvas ROC (receiver operating characteristics). As correlações entre os achados do PERG, do OCT e do CV foram avaliadas pela correlação de Pearson ou Spearman. RESULTADOS: Comparadas aos controles, as espessuras do OCT, da CFNR peripapilar, CFNR macular, CCG macular e EMT foram significativamente menores em pacientes com PTC. Com relação ao PERG, houve redução da amplitude de N95 e P50+N95, e aumento do tempo de pico de N95, ambos para o estímulo de 48\', em olhos doentes, quando comparados ao grupo controle. Correlações estatisticamente significantes foram encontradas entre os valores de amplitude do PERG e da espessura retiniana do OCT. As reduções de espessura das camadas retinianas do OCT também foram significativamente associadas à perda de sensibilidade do CV. CONCLUSÕES: O PERG e o OCT foram capazes de demonstrar a perda anatômica e funcional dos doentes com papiledema decorrente de PTC, apresentando significativa correlação entre os métodos analisados. Tanto o OCT avaliando as medidas maculares como o PERG podem ser úteis na monitorização da perda neural retiniana de pacientes com papiledema decorrente da síndrome do PTC / PURPOSE: To evaluate the ability of the full field pattern electroretinogram (PERG) to detect functional changes of retina in eyes with resolved papiledema from patients with pseudotumor cerebri (PTC). To analyze full thickness macular measurements, peripapillary retinal nerve fiber layer (RNFL) thickness as well as segmented inner retinal layers in patients with PTC using of Fourier domain optical coherence tomography (FD-OCT) and compare them with normal eyes. To study the correlation between the PERG parameters, the optical coherence tomography (OCT) measurements and the visual field (VF) sensitivity loss, using standard automated perimetry. METHODS: Fifty-two eyes with resolved papilledema of 29 patients with PTC syndrome were submitted to a complete ophthalmic examination including VF, PERG and OCT. The following OCT measurements were analyzed: the peripapillary RNFL thickness, the total macular thickness (TMT), which was sub-divided in 8 sectors according to the Early Treatment Diabetes Retinopathy Study map, and the segmented inner macula layers, RNFL, the ganglion cell layer (GCL) and inner nuclear layer (INL). The VF results were analyzed through the mean deviation (MD) and the different sectors of the VF according to their correspondence to Garway-Heath optic nerve map. Central mean deviation, an average from VF sensitivity for the 12 and 16 central points, an area roughly equivalent to the area tested by macular cube scan protocol and PERG, was evaluated in patients and controls. Generalized estimating equation models accounting for inter-eye correlations were used to compare the results among different groups. Areas under ROC (receiver operating characteristics) curves were also calculated and compared. The correlations between the findings of the PERG, OCT and VF were assessed by Pearson correlation coefficients or Spearman\'s rank correlation coefficients. RESULTS: Compared to controls, the OCT thickness of the peripapillary RNFL, macular RNFL, macular GCL and TMT were significantly thinner in eyes with PTC. When PERG was studied, the amplitude of P50 and N95 + N95 were significantly reduced and N95 peak time increased, both based on 48 min check size, in patients when compared with normal controls. Significant correlations were found between the PERG amplitude and OCT retinal thickness. The decreased thickness of the OCT retinal layers was also significantly associated with VF sensitivity loss. CONCLUSIONS: PERG and OCT were able to demonstrate anatomical and functional loss in patients with resolved papiledema from PTC, showing significant correlation between the methods analyzed. It is known that the main morbidity of this disease is visual impairment. It is therefore of great importance to monitor the visual function during treatment. Whereas papilledema may be reversible at early stages, permanent visual loss may occur. These findings suggest that both measurements can be complementary in assessing axonal loss in patients with PTC

A Pressão intracraniana (PIC) é um dos principais parâmetros fisiológicos em animais e humanos e sua morfologia é extremamente importante. Entretanto, todos os métodos de monitoramento existentes no mercado são invasivos, existindo uma ampla demanda por sistemas não invasivos, expandindo assim o campo de pesquisas acerca desse importante parâmetro neurológico, que só não é melhor estudado devido a forma invasiva de ser monitorado. A motivação é fazer com que o monitoramento da PIC seja tão comum e tão essencial quanto é hoje o monitoramento da pressão arterial, facilitando o diagnóstico e até prognóstico de diversas doenças. Este trabalho analisa e implementa melhorias de um sistema não invasivo de monitoramento da pressão intracraniana, baseado em extensometria. Um dos objetivos, no que tange o desenvolvimento do produto, é analisar o equipamento como um todo - Sensor, Hardware, Firmware e Software - e propor melhorias a partir dos testes realizados. Os testes realizados In vivo mostraram uma boa correlação do sinal com um sistema Gold Stardard, evidenciando o potencial promissor do método. / The intracranial pressure (ICP) is one of the main physiological parameters in animals and humans and its morphology is extremely important. However, all monitoring methods available in the market are invasive and there is a large demand for non-invasive systems, thus expanding the scope of research on this important neurological parameter, that just is not further studied because of the invasive method of monitoring. The motivation is to make monitoring the ICP as common and as essential, as monitoring the blood pressure is nowadays, facilitating diagnosis and even prognosis of various diseases. This work analyzes and implements improvements in a non-invasive intracranial pressure monitoring system based on extensometer. One of the goals, regarding product development, is to analyze the unit as a whole- Sensor, Hardware, Firmware and Software- and propose improvements from the tests. The in vivo tests showed a good correlation with a Gold Stardard system signal showing the promising potential of the method.

Os objetivos deste estudo foram: (1) Descrever e analisar as principais características da hipertensão intracraniana em pacientes com meningoencefalite criptocócica e aids; (2) Descrever e comparar as características clínicas, epidemiológicas, laboratoriais e evolutivas associadas à presença de hipertensão intracraniana em pacientes com meningoencefalite criptocócica e aids; (3) Identificar fatores associados à má evolução em pacientes com meningoencefalite criptocócica e aids. Este é um estudo de coorte prospectivo que avaliou 34 pacientes soropositivos para o HIV internados no Instituto de Infectologia Emílio Ribas no período de janeiro de 2003 a março de 2004. Definição de caso: paciente com sinais e sintomas de meningoencefalite com cultura de líquor positiva para Cryptococcus neoformans. Hipertensão intracraniana foi definida como pressão liquórica inicial >= 200 mmH2O. Todos os pacientes receberam tratamento inicial com anfotericina B e aqueles casos que apresentaram hipertensão intracraniana foram submetidos a um algoritmo específico de punções diárias de alívio ou shunt. Os pacientes foram analisados durante o período de internação. Vinte e seis pacientes eram do gênero masculino (76,5%); com média de idade de 35,4 anos; com imunodepressão grave (média de cels T CD4+ = 35,4 anos). Sete (20,6%) pacientes souberam do diagnóstico da infecção pelo HIV a partir da criptococose, que foi a primeira doença definidora de aids em 61,8% dos casos. Hemocultura foi positiva em 52,9% dos casos. Hipertensão intracraniana ocorreu em 20 (58,9%) pacientes à admissão e em 25 (73,52%) em qualquer momento da evolução clínica. Os fatores associados estatisticamente à ocorrência de hipertensão intracraniana foram: turvação visual (P=0,02), alteração de nervos cranianos (P=0,03), e número de células fungicas no LCR > 100 células/ mm3 à admissão (P=0,036). As punções diárias de alívio foram eficazes em controlar a hipertensão intracraniana em 21 (62%) casos e shunt foi realizado em seis casos. A mortalidade geral foi de 26,5%, porém na maioria dos casos a causa do óbito foi atribuída à infecção hospitalar. Os fatores estatisticamente associados à evolução para óbito foram: hipertensão arterial sistêmica (P=0,048), coma (P=0,048), déficit motor (P=0,014) e número elevado de células fúngicas no líquido cefalorraquidiano (P=0,030). / The objectives of this study were: (1) To describe and analyze the main characteristics associated to elevated intracranial pressure in patients with Cryptococcal meningoencephalitis and aids. (2) To describe and to compare clinical, epidemiologic, laboratorial and outcome characteristics associated to elevated intracranial pressure in patients with Cryptococcal meningoencephalitis and aids (3) To identify associated factors to poor outcome in patients with Cryptococcal meningoencephalitis and aids This is a prospective cohort study that analyzed 34 HIV infected patients hospitalized at Emilio Ribas Institute during the period of January 2003 to March 2004. Case definition: Patients with clinical manifestations of meningoencephalitis and isolation of Cryptococcus neoformans from Cerebrospinal Fluid. Elevated intracranial pressure was defined as cerebrospinal fluid opening pressure >= 200 mmH2O. All patients were initially treated with amphotericin B and that who presented with elevated intracranial pressure were submitted to a specific algorithm of repeated lumbar drainage or shunt. The patients were followed during hospitalization period. Results: Twenty six patients were male (76.5%); with mean of age of 35, 4 years. The means of T CD4 count was 28,5 cell/ . Cryptococcosis led to diagnosis of HIV infection in 20,6% of patients, whereas it was the aids-defining disease in 61,8% of patients. Blood cultures were positive in 52,9% of cases. Elevated intracranial pressure was presented in 20 (58,9%) patients at admission, and in 25 patients (73,52%) during evolution. Elevated intracranial pressure was associated to visual turvation (P=0,02), cranial nerve abnormalities (P=0,03) and number of fungal cells ³ 100 cells/ mm3 at admission (P=0,036). Lumbar puncture was efficient to control elevated intracranial pressure in 21 (62%) cases and six patients were submitted to shunt. Overall mortality was 26,5%. Factors associated to death were: arterial hypertension (P=0,048), coma (P=0,048), motor deficits (P=0,014) and raised number of fungal cells in cerebrospinal fluid at admission (P=0,03).

Despite the vast myriad of applications and the long way it has come, MRI is still a relatively new field of knowledge with much prospect for more advancement and expansion. This work is mainly concerned with two gradient echo imaging methods which are directly or indirectly related to blood vessel imaging as well as iron depiction in the human brain. In each case, new methods are introduced that overcome existing limitations. For blood vessel imaging, 3D Time-of-Flight (TOF) MR angiography (MRA) with its known capability to image arteries as well as veins was implemented at 3.0 T. At this field strength, the significant RF profile variability due to RF inhomogeneity is a liability for circle-of-Willis imaging in the human brain that was overcome by introducing a new means to counter the RF effects through increased slope of the ramped pulse. In addition a new method is introduced for TOF MRA with two-in-one arterial and venous 3D TOF imaging to overcome the significant scan time overhead of a traditional second venous scan and for cutting down RF power utilization. Using this method, total scan time could be reduced by as much as 46% and specific absorption rate (SAR) due to spatial saturation could be reduced by as much as 92%. For iron sensitive imaging, Susceptibility Weighted Imaging (SWI) was developed at 4.7 T. The phase SWI method was used to visualize lesions in Multiple Sclerosis (MS) patients and was experimentally compared to the visibility on standard T2 weighting with results demonstrating visualization of new lesions, with 18% of total lesions exclusively visible on SWI. A new approach to 3D imaging was also introduced to enable accurate oblique SWI scanning while overcoming the current restriction to axial imaging to produce correct phase effects for oblique imaging. New results from oblique phase imaging were presented and the phase measurements from key brain structures were successfully validated against images obtained by the current standard of axial imaging.

L'objectif de notre thèse est de contribuer à une meilleure délimitation de la forme et de l'extension de tumeurs intracrâniennes afin de pouvoir mieux les traiter par radiothérapie conformationnelle. Plusieurs approches ont été utilisées. Par une étude anatomo-pathologique autopsique, nous avons pu démontrer que les métastases cérébrales de plusieurs types de tumeurs s'étendent au moins 1 mm au-delà de leur bord macroscopiquement visible. Les métastases de tumeurs pulmonaires à petites cellules sont celles pour lesquelles nous observons la plus grande extension. En utilisant des techniques de spectroscopie et de l'imagerie par RMN, nous avons observé que des discordances existent dans 47% des voxels examinés. Le plus souvent, l'image apparaît pathologique en RMN et normale en spectroscopie, peut-être en raison d'un oedème périlésionnel important. Une troisième approche a été l'analyse comparative de l'extension de méningiomes intracrâniens par la RMN et par une nouvelle méthode d'imagerie métabolique (PET scan à un acide aminé marqué au fluor 18). Tous les méningiomes sont bien visualisés par le PET scan. Une concordance complète entre image de RMN et de PET scan est observée dans 54% des cas, l'image est plus étendue en PET scan dans 38 % des cas et la situation inverse est observée dans 8% des cas. Enfin, nous avons validé toute la chaîne de traitement en radiochirurgie sur des neurinomes de l'acoustique. Nous obtenons des résultats cliniques comparables à ceux de grandes séries publiées. En conclusion, nos travaux montrent que l'image anatomique seule (la RMN) est insuffisante pour délimiter la plupart des tumeurs intracrâniennes et que des méthodes complémentaires (spectroscopie, imagerie dite métabolique) sont nécessaires pour la préparation au traitement par radiothérapie de précision.

The neurological wake-up test, NWT, is a clinical monitoring tool that can be used to evaluate the level of consciousness in patients with traumatic brain injury (TBI) and subarachnoid haemorrhage (SAH) during neurocritical care (NCC). Since patients with severe TBI or SAH are often treated with mechanical ventilation and sedation, the NWT requires that the continuous sedation is interrupted. However, interruption of continuous sedation may induce a stress response and the use of the NWT in NCC is controversial. The effects of the NWT on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated in 21 patients with TBI or SAH. Compared to baseline when the patients were sedated with continuous propofol sedation, the NWT resulted in increased ICP and CPP (p&lt;0.05). Next, the effects of the NWT on the stress hormones adrenocorticotrophic hormone (ACTH), cortisol, epinephrine and norepinephrine were evaluated in 24 patients. Compared to baseline, the NWT caused a mild stress response resulting in increased levels of all evaluated stress hormones (p&lt;0.05). To compare the use of routine NCC monitoring tools, the choice of sedation and analgesia and the frequency of NWT in Scandinavian NCC units, a questionnaire was used. The results showed that all 16 Scandinavian NCC units routinely use ICP and CPP monitoring and propofol and midazolam were primary choices for patient sedation in an equal number of NCC units. In 2009, the NWT was not routinely used in eight NCC units whereas others used the test up to six times daily. Finally, intracerebral microdialysis (MD), brain tissue oxygenation (PbtiO2) and jugular bulb oxygenation (SjvO2) were used in 17 TBI patients to evaluate the effect of the NWT procedure on focal neurochemistry and cerebral oxygenation. The NWT did not negatively alter interstitial markers of energy metabolism or cerebral oxygenation. In conclusion, the NWT induced a mild stress response in patients with TBI or SAH that did not result in a detectable, significant secondary insult to the injured brain. These results suggest that the NWT may safely be used as a clinical monitoring tool in the NCC of severe TBI and SAH in a majority of patients.

During brain activity neurons release the major excitatory transmitter glutamate, which is taken up by astrocytes and converted to glutamine. Glutamine returns to neurons for re-conversion to glutamate. This glutamate-glutamine cycle is energy demanding. Glutamate turnover in injured brain was studied using an animal iron-induced posttraumatic epilepsy model and using neurointensive care data from 33 patients with spontaneous subarachnoid hemorrhage (SAH). Immunoblotting revealed that the functional form of the major astrocytic glutamate uptake protein GLT-1 was decreased 1-5 days following a cortical epileptogenic iron-injection, presumably due to oxidation-induced aggregation. Using microdialysis it was shown that the GLT-1 decrease was associated with increased interstitial glutamate levels and decreased interstitial glutamine levels. The results indicate a possible posttraumatic and post-stroke epileptogenic mechanism. Analysing 3600 microdialysis hours from patients it was found that the interstitial lactate/pyruvate (L/P) ratio correlate with the glutamine/glutamate ratio (r =-0.66). This correlation was as strong as the correlation between L/P and glutamate (r=0.68) and between lactate and glutamate (r=0.65). Pyruvate and glutamine correlated linearly (r=0.52). Energy failure periods, defined as L/P&gt;40, were associated with high interstitial glutamate levels. Glutamine increased or decreased during energy failure periods depending on pyruvate. Energy failure periods were clinically associated with delayed ischemic neurological deficits (DIND) or development of radiologically verified infarcts, confirming that L/P&gt;40 is a pathological microdialysis pattern that can predict ischemic deterioration after SAH. DIND-associated microdialysis patterns were L/P elevations and surges in interstitial glutamine. Glutamine and pyruvate correlated with the cerebral perfusion pressure (r=0.25, r=0.24). Glutamine and the glutamine/glutamate ratio correlated with the intracranial pressure (r=-0.29, r=0.40). Glutamine surges appeared upon substantial lowering of the intracranial pressure by increased cerebrospinal fluid drainage. Increased interstitial glutamine and pyruvate levels may reflect augmented astrocytic glycolysis in recovering brain tissue with increased energy demand due to a high glutamate-glutamine turnover.