Intraobserver variability of pulsatility index measurements in three fetal vessels in the first trimester

Índices de resistência e pulsatilidade das artérias uterinas no primeiro e segundo trimestres de gestações normais

OBJETIVO: Determinar os índices de resistência (IR) e pulsatilidade (IP) nas artérias uterinas durante o primeiro e segundo trimestres de gestação. MATERIAIS E MÉTODOS: Realizamos estudo prospectivo longitudinal em 44 mulheres normais, da 8ª a 12ª e na 22ª semanas de gestação. A dopplervelocimetria foi realizada em ambas as artérias uterinas por meio do IR e do IP. Utilizamos volume de amostra de 1 a 2 mm, filtro de 50 a 70 Hz e ângulo de insonação abaixo de 60°. RESULTADOS: O IR e o IP da artéria uterina no primeiro trimestre foram maiores da 8ª a 12ª do que na 22ª semana de gestação. O IR e o IP da artéria uterina, no primeiro trimestre, com incisura foram de 0,83 ± 0,07 e 2,32 ± 0,79, e sem incisura, de 0,71 ± 0,16 e 1,61 ± 0,78, respectivamente. No segundo trimestre, o IR e o IP da artéria uterina com incisura foram de 0,59 ± 0,09 e 1,03 ± 0,32, e sem incisura, de 0,44 ± 0,09 e 0,63 ± 0,19, respectivamente. CONCLUSÃO: Estabelecemos os valores de referência do IR e do IP das artérias uterinas de gestantes normais no primeiro e segundo trimestres de gestação.

Evaluation of fetal cerebrovascular circulation and brain development: the role of ultrasound and Doppler

The human fetal brain is protected from pressure changes by autoregulation of the cerebral circulation. However, antenatal intrauterine cerebrovascular events are found to play an important role in the pathogenesis of perinatal brain damage. Changes in placental vascular resistance, cardiac contractibility, vessel compliance, and blood viscosity alter the normal dynamics of fetal cerebral circulation. The introduction of various sonographic techniques and the collection of data from the arterial and venous cerebral circulation provide a powerful tool for the evaluation of physiological and pathological hemodynamic events. Anatomic and physiological considerations of cerebral vasculature in healthy and disease states are relevant in studying brain development and variations in fetal brain blood perfusion. The major role of ultrasound and Doppler modalities in the evaluation of fetal cerebrovascular circulation is enabled by implementation of these considerations. Changes in flow characteristics in fetal cerebral vasculature can be used for clinical decision making in situations of fetal compromise, such as growth restriction and anemia.

Repeatability of power Doppler sonography of cervical lymph nodes

This study was undertaken to investigate the repeatability (intraobserver variability) of power Doppler sonography in assessment of cervical lymph nodes. Power Doppler sonography was performed twice in 20 healthy subjects to evaluate the repeatability of measurement of size, blood flow velocity (peak systolic velocity, PSV, and end diastolic velocity, EDV) and vascular resistance (resistance index, RI, and pulsatility index, PI) of cervical nodes. A total of 70 power Doppler sonograms were reviewed to evaluate the repeatability of assessment of vascular pattern, degree of vascularity and displacement of vessels of cervical lymphadenopathy. In the 20 subjects, 139 normal cervical nodes were detected in the first scan and they were re-scanned in the second scan. One node was detected in the second scan, but not in the first scan. Of the total, 50 cervical nodes showed arterial flow in both scans, and blood flow velocity and vascularity resistance were measured. The mean value of PSV, EDV, RI and PI have a higher repeatability than their highest and lowest values. There is a high repeatability in the measurement of maximum transverse diameter (97%), mean PSV (95%), mean EDV (96%), mean RI (86%) and mean PI (87%). The repeatability in evaluation of vascular pattern (85%), degree of vascularity (95%) and displacement of vessels (88%) are also high. Results suggest that power Doppler sonography is a reliable method in assessment of the vasculature of cervical lymph nodes.