Atualização sobre ultrassom doppler das artérias vertebrais: síndrome do roubo da subclávia / An update on doppler ultrasound of vertebral arteries: subclavian steal syndrome

A síndrome do roubo da subclávia refere-se a uma desordem vascular na qual ocorre inversão do fluxo de sangue da artéria vertebral ipsilateral, decorrente de uma estenose proximal à sua origem, geralmente uma oclusão da artéria subclávia ou, mais raramente, do troncobraquiocefálico. É uma doença relativamente rara, relatadaem aproximadamente 6% dos pacientes assintomáticos com sopros cervicais. O Doppler pulsado (PW) é útil na análiseda artéria vertebral, registrando informações capazes de identificar a presença da Síndrome do Roubo da Subclávia. Com base nas alterações hemodinâmicas da artéria vertebralavaliadas pelo estudo com Doppler espectral, pode ser classificada nos tipos 1 (oculto), 2 (intermitente ou parcial)e 3 (completo). Com o advento da angioplastia transluminal percutânea e, em seguida, dos stents, muitos advogam essa combinação de procedimentos como o tratamento de escolha dos casos sintomático dessa síndrome.

Pulsed tissue Doppler imaging of the left ventricular septal mitral annulus in healthy dogs

This study evaluated pulsed TDI variables including the isovolumic time interval and duration of the major wave in a population of large healthy dogs. Longitudinal myocardial motion at the septal mitral annulus was evaluated with pulsed TDI in 45 healthy adult dogs. Maximal myocardial velocities, isovolumic time intervals, and duration of the myocardial waves were measured. The correlation between time intervals and velocity variables was also investigated. The mean maximal systolic velocity was 6.92 +/- 1.78 cm/sec, the mean early diastolic velocity (Em) was 6.58 +/- 1.81 cm/sec, the mean late diastolic velocity (Am) was 5.10 +/- 2.00 cm/sec, the mean isovolumic contraction time (IVCT) was 53.61 +/- 95.13 msec, and the mean isovolumic relaxation time (IVRT) was 26.74 +/- 57.24 msec. The early diastolic mitral inflow velocity (E)/Em ratio was 10.94 +/- 3.27 while the Em/Am ratio was 1.40 +/- 0.40. There was a negative correlation between Am duration and Am amplitude, and a positive correlation between the IVRT and Em/Am ratio (p < 0.05). The normal LV parameter using pulsed TDI method could be used as the reference range for identifying myocardial dysfunction in dogs.

Correlation between the Doppler velocimetry findings of the uterine arteries during the first and second trimesters of pregnancy / Correlação entre os achados doppplervelocimétricos das artérias uterinas no primeiro e segundo trimestres da gestação

OBJECTIVES: Evaluate the feasibility of transvaginal uterine artery Doppler examination in the first and second trimesters of pregnancy, establish reference ranges in a Brazilian population and examine the correlation between these Doppler findings. METHODS: Longitudinal prospective study at the antenatal clinic of a tertiary teaching hospital. Uterine artery Doppler examinations were carried out transvaginally at 11 to 14 weeks and 20 to 25 weeks of gestation. Uterine artery mean pulsatility index (PI) distributions were determined and the presence or absence of an early diastolic notch was also noted. The degree of correlation between first and second trimester Doppler findings was examined. RESULTS: Three hundred and forty four women with live singleton pregnancies and normal outcome were first examined at a mean gestation of 12.7 weeks. The values corresponding to the 50th and 95th centiles of mean PI were 1.69 and 2.48. Bilateral notches were observed in 44 percent of cases and unilateral notches were present in 19 percent. Second trimester Doppler examinations were carried out at a mean gestation of 23.2 weeks and corresponding figures for the 50th and 95th centiles were 1.03 and 1.57. Bilateral notches were noted in 4.4 percent of the cases. First trimester impedance indices were significantly higher and positively correlated to second trimester findings (r = 0.42, p<0.0001). CONCLUSION: Uterine artery Doppler examination can be successfully performed transvaginally and incorporated into scans that are routinely offered to women during their antenatal care in the first and second trimesters. Doppler indices obtained during the first trimester are significantly higher than those of the second trimester and findings at both scans are significantly correlated.

OBJETIVO: Avaliar a aplicabilidade de realizar exames dopplervelocimétricos endovaginais das artérias uterinas no primeiro e segundo trimestres da gestação, definir valores normais na população brasileira e examinar a correlação entre esses achados. MÉTODOS: Estudo prospectivo longitudinal conduzido em Hospital Universitário Terciário. Os exames dopplervelocimétricos das artérias uterinas foram realizados pela via endovaginal, entre 11 a 14 semanas e 20 a 25 semanas de gestação. Em cada período gestacional estudado, a distribuição dos valores dos índices de pulsatilidade (IP) médio foi descrita e diferentes percentis calculados. Também foi anotada a presença ou ausência de incisura uterina protodiastólica. Os achados dopplervelocimétricos observados no primeiro trimestre foram correlacionados com os achados do segundo trimestre. RESULTADOS: Trezentos e quarenta e quatro mulheres com gestações únicas de desfecho normal foram examinadas inicialmente em idade gestacional média de 12,7 semanas. Os valores correspondentes aos percentis 50 e 95 para o IP médio foram de 1,69 e 2,48, respectivamente. Incisura bilateral foi observada em 44 por cento dos casos e unilateral em 19 por cento. Na segunda avaliação, realizada em idade gestacional média de 23,2 semanas, os valores correspondentes aos percentis 50 e 95 do IP médio foram de 1,03 e 1,57, respectivamente. Incisura bilateral foi observada em 4,4 por cento dos casos na segunda avaliação. Os índices dopplervelocimétricos do primeiro exame se correlacionaram de forma significativa e positiva com os valores do segundo trimestre (r= 0,42; p<0,0001). CONCLUSÃO: O estudo dopplervelocimétrico endovaginal das artérias uterinas pode ser realizado de forma satisfatória e incorporado nos exames ultrassonográficos oferecidos como parte da rotina de acompanhamento pré-natal no primeiro e segundo trimestres da gestação. Índices dopplervelocimétricos uterinos médios observados entre 11 e 14 semanas são ...

Prediction of small-for-gestational age infents by quantitative assessment of diastolic notch in uterine artery flow velocity waveforms

To assess the performance and clinical usefulness of the notch depth index [NDI] in predicting small-for-gestational age infants [SGA] in comparison to the previously defined abnormalities in uterine blood flow velocity waveforms; peak systolic over protodiastolic velocities [A/C] ratio. Presence of protodiastolic notch and resistance index [RI]. This prospective clinical study included evaluation of pulsed Doppler abnormalities uterine artery velocity waveforms in 673 nulliparae with normal singleton pregnancies at 16-18 weeks and at 26 weeks gestation. Main outcome measures: Delivery of small for gestational age [SGA] infants. SGA developed in 11% of nulliparae. Although early Doppler screening was associated with high false positive results, yet two-stage screening avoided false negative cases. NDI was found to be a better predictor than other Doppler indices [A/C ratio, protodiastolic notch and RI]. NDI improved, both sensitivity and PPV as determined by other Doppler indices. NDI measurements were clinically useful in predicting for gestational age infant than other conventional Doppler indices

Color Doppler sonography with contrast in the differentiation of ovarian tumors

The objective of this study was to differentiate benign ovarian tumors from malignant ones before surgery using color and pulsed Doppler sonography, and to compare results obtained before and after use of contrast medium, thereby verifying whether contrast results in an improvement in the diagnostic sensitivity. METHODS: Sixty two women (mean age 49.9 years) with ovarian tumors were studied, 45 with benign and 17 with malignant tumors. All women underwent a transvaginal color Doppler ultrasonographic exam. A study of the arterial vascular flow was made in all tumor areas, as well as an impedance evaluation of arterial vascular flow using the resistance index. RESULT: Localization of the vessels in the tumor revealed a greater proportion of malignant tumors with detectable internal vascular flows (64 percent) than benign tumors with such flows (22 percent). There was a considerable overlap of these findings. The use of contrast identified a greater number of vessels with confirmation in the totality of tumors, but did not improve the Doppler capacity in tumoral differentiation. Malignant tumors presented lower values of resistance index than the benign ones, whether or not contrast was used. The cutoff value for resistance index that better maximized the Doppler sensitivity and specificity was 0.55. Through this value, an increase of the sensitivity after contrast use was obtained, varying from 47 percent to 82 percent, while specificity remained statistically unchanged. CONCLUSION: Although the injection of a microbubble agent improved the sensitivity of the method detecting vascularization of tumors, a positive finding for vascularization by this method was not clinically useful in the differentiation of benign and malignant ovarian tumors

Application of pulsed Doppler ultrasound for the evaluation of small intestinal motility in dogs

The purpose of this study was to verify whether small intestinal peristalsis could be observed and quantitatively assessed using pulsed-Doppler ultrasound. Pulsed-Doppler ultrasound was used to evaluate small intestinal peristalsis after a meal in ten normal dogs and ten sedated dogs. The small intestinal peristalses were measured 0, 1, 3, 6, 9, 12, and 24 hours after a 24-hour fast and after feeding. The number of small intestinal peristalsis were 0.133/min, 0.100/min, 0.033/min, 0.167/min, 0.070/min, 0.067/min, and 0.100/min in the fasted dogs, and 1.667/ min, 0.933/min, 1.133/min, 1.234/min, 1.933/min, 1.533/ min, and 0.533/min in fed dogs, respectively. In the dogs sedated with xylazine HCl, the number of small intestinal peristalsis was significantly reduced (p<0.01). However, in the dogs treated with ketamine HCl and acepromazine, the number of small intestinal peristalsis remained unchanged. Therefore, it can be concluded that pulsed-Doppler ultrasound allows graphic visualization of the intestinal movements, which can be subjected to qualitative and quantitative analysis, and may be suitable for a non-invasive study of small intestinal motility.