Browsing by Author "Pereira, P"
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- 2D visualization and measurement of the fetal optic chiasm. Improving the counselling of antenatal diagnosis of agenesis of the septi pellucidi.Publication . Viñals, F; Ruiz, P; Correa, F; Pereira, PTo develop an objective method to visualize and measure the optic chiasm (OC) through a 2D coronal vaginal plane and to report measurements in fetuses with agenesis of the septi pellucidi (SP). METHODS: This was a prospective cross-sectional study of 115 morphologically normal fetuses in low-risk pregnancies, between 21 and 30 weeks' gestation. OC was measured in a coronal plane at the level of the third ventricle and was seen as a horizontally aligned dumbbell-shaped structure of moderate echogenicity. In addition, OC measurements from eight fetuses with agenesis of the SP and complete follow-up were compared to the reference range. RESULTS: OC measurements were obtained in 110 of 115 normal fetuses. OC growth occurred linearly with gestational age. Our method demonstrated good intraobserver repeatability and excellent interobserver reproducibility. Among the eight fetuses with agenesis of the SP, four had normal measurements, and five normal vision postnatally. Pregnancy continued to term in all cases and the follow-up period varied from six months to seven years. CONCLUSION: Our study demonstrates that it is possible to visualize and measure the OC directly through a 2D ultrasound coronal plane. In fetuses with agenesis of the SP, the morphology and width of the OC visual pathway could prove a relevant tool in assessing its development. It would also provide support to the difficult antenatal counselling when faced with the diagnosis of agenesis of the SP.
- Avaliação dos gliomas cerebrais por técnicas avançadas de ressonância magnéticaPublication . Graça, J; Palma, T; Pereira, P; Medina, P; Ribeiro, C; Evangelista, PA Ressonância Magnética (RM) é o método de escolha para a avaliação imagiológica dos gliomas cerebrais. A determinação do grau de malignidade destas neoplasias tem implicação na abordagem terapêutica e no prognóstico do doente. Os autores focam-se na utilidade das técnicas avançadas de RM, nomeadamente espectroscopia protónica, perfusão e difusão na avaliação pré e pósterapêutica dos gliomas. Estas técnicas constituem um método complementar à RM convencional, permitindo melhorar a detecção do grau de malignidade dos gliomas de forma mais precoce e não invasiva. Para além disso, são úteis na determinação das áreas tumorais com maior malignidade, alvos preferenciais para biopsia estereotáxica e terapêutica. Têm particular utilidade na distinção entre tumor residual, recidiva tumoral e necrose de radiação.
- Dyschromatopsia in Multiple Sclerosis Patients: A Marker of Subclinical Involvement?Publication . Felgueiras, H; Parra, J; Cruz, S; Pereira, P; Santos, A; Rua, A; Meira, D; Fonseca, P; Pedrosa, C; Cardoso, J; Almeida, C; Araújo, M; Santos, EBACKGROUND: In multiple sclerosis (MS), even in the absence of a clinical episode of optic neuritis (ON), the optic nerve and retinal nerve fiber layer (RNFL) may be damaged leading to dyschromatopsia. Subclinical dyschromatopsia has been described in MS associated with lower motor and cognitive performances. OBJECTIVES: To set the prevalence of dyschromatopsia in eyes of MS patients without a history of ON, to compare its prevalence in patients with and without ON history, and to explore the association between dyschromatopsia and disease duration, average peripapillary RNFL thickness, macular volume, and cognitive and motor performances. METHODS: An observational cross-sectional study was conducted at multiple medical centers. Data were collected after single neurological and ophthalmological evaluations. Dyschromatopsia was defined by the presence of at least 1 error using Hardy-Rand-Rittler plates. RESULTS: In our population of 125 patients, 79 patients (63.2%) never had ON and 35 (28.8%) had unilateral ON. The prevalence of dyschromatopsia in eyes of patients without ON was 25.7%. Patients with dyschromatopsia had a statistically significant lower RNFL thickness (P = 0.004 and P = 0.040, right and left eyes, respectively) and worse performance in symbol digit modalities test (P = 0.012). No differences were found in macular volume or motor function tasks. CONCLUSIONS: Dyschromatopsia occurs frequently in MS patients. It may be associated with a worse disease status and possibly serve as a marker for the detection of subclinical disease progression since it was detected even in the absence of ON. It correlated with thinner peripapillary RNFL thickness and inferior cognitive performance.
- Two-dimensional visualization and measurement of the fetal optic chiasm: improving counseling for antenatal diagnosis of agenesis of the septum pellucidum.Publication . Viñals, F; Ruiz, P; Corre, F; Pereira, POBJECTIVE: To develop an objective method for visualizing and measuring the fetal optic chiasm (OC) using transvaginal two-dimensional (2D) ultrasound in the coronal plane and to report measurements in fetuses with agenesis of the septum pellucidum (SP). METHODS: This was a prospective cross-sectional study of 115 morphologically normal fetuses in low-risk pregnancies, between 21 and 30 weeks' gestation. The OC was measured in a coronal plane at the level of the third ventricle and was seen as a horizontally aligned dumbbell-shaped structure of moderate echogenicity. In addition, OC measurements from eight fetuses with agenesis of the SP and complete follow-up were compared with the reference range. RESULTS: OC measurements were obtained in 110/115 normal fetuses and showed that OC increases linearly with gestational age. Our method of measurement demonstrated good intraobserver repeatability and excellent interobserver reproducibility. Among the eight fetuses with agenesis of the SP, five had normal OC measurements and five had normal vision postnatally. Pregnancy continued to term in all cases and the follow-up period varied from 6 months to 7 years. CONCLUSION: Our study demonstrates that it is possible to visualize and measure the OC directly on a 2D ultrasound coronal plane. In fetuses with agenesis of the SP, the morphology and width of the OC visual pathway could prove a relevant tool for assessing its development. It would also help in the difficult task of providing antenatal counseling when faced with the diagnosis of agenesis of the SP.