Laser-doppler flowmetry Archives - Revista Brasileira de Ginecologia e Obstetrícia
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2005;27(7):387-392
DOI 10.1590/S0100-72032005000700004
PURPOSE: to assess peak systolic velocity (PSV) and the resistance index (RI) in the middle cerebral artery (MCA), suprarenal aorta (SRA) and infrarenal aorta (IRA) of the fetus and in the umbilical artery (UA) between the 22nd and 38th week of gestation. METHODS: a prospective study which evaluated the parameters of 33 normal fetuses in the 22nd, 26th, 30th, and 38th week of gestation. Pregnant women with a singleton fetus with no diseases or complications and who agreed to participate were included in the study. Exclusion criteria were fetal malformations, discontinuation of prenatal care visits and mothers who smoked, used alcohol or illicit drugs. Ultrasound examinations were performed by a single observer. For the acquisition of the Doppler velocimetry tracing in the MCA, SRA, IRA and UA, the sample volume was 1 to 2 mm, placed in the center of the arteries. The insonation angle was 5º to 19º in the MCA, below 45º in the SRA and IRA, and less than 60º in the UA. We used a wall filter of 50-100 Hz. The parameters were calculated automatically with the frozen image, three measurements being made. The final result was obtained by the arithmetic mean of the three values. Data were analyzed by analysis of variance (ANOVA), post hoc Bonferroni test, Pearson's correlation, and regression analysis. The level of significance was set at p<0.05 in all analyses. RESULTS: PSV increased from 26.3 to 57.7 cm/s in the MCA between the 22nd and the 38th week of gestation (p<0.05). In the SRA and in the IRA, PSV increased between the 22nd and 34th week of gestation, from 74.6 and 59.0 cm/s to 106.0 and 86.6 cm/s, respectively (p<0.05). In the UA, PSV increased between the 22nd and the 34th week of gestation, but decreased from 55.5 to 46.2 cm/s between the 34th and the 38th week of gestation. In the MCA, the RI was lower in the 22nd (0.81) and 38th week of gestation (0.75) and higher (0.85) in the 26th week (p<0.05). In the SRA, the RI values were stable in all weeks and in the IRA they were stable in most weeks (p>0.05). In the UA, RI decreased from 0.69 to 0.56 between the 22nd and 38th week of gestation (p<0.05). CONCLUSION: in normal fetuses, in the second half of gestation PSV increased in the MCA, SRA and IRA, decreasing in the UA between the 34th and 38th week of gestation. RI was lower in the 22nd and 38th weeks of gestation in the MCA, decreased between the 22nd and the 38th week in the UA, and was constant in most of the gestational weeks in the SRA and IRA.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2005;27(7):387-392
DOI 10.1590/S0100-72032005000700004
PURPOSE: to assess peak systolic velocity (PSV) and the resistance index (RI) in the middle cerebral artery (MCA), suprarenal aorta (SRA) and infrarenal aorta (IRA) of the fetus and in the umbilical artery (UA) between the 22nd and 38th week of gestation. METHODS: a prospective study which evaluated the parameters of 33 normal fetuses in the 22nd, 26th, 30th, and 38th week of gestation. Pregnant women with a singleton fetus with no diseases or complications and who agreed to participate were included in the study. Exclusion criteria were fetal malformations, discontinuation of prenatal care visits and mothers who smoked, used alcohol or illicit drugs. Ultrasound examinations were performed by a single observer. For the acquisition of the Doppler velocimetry tracing in the MCA, SRA, IRA and UA, the sample volume was 1 to 2 mm, placed in the center of the arteries. The insonation angle was 5º to 19º in the MCA, below 45º in the SRA and IRA, and less than 60º in the UA. We used a wall filter of 50-100 Hz. The parameters were calculated automatically with the frozen image, three measurements being made. The final result was obtained by the arithmetic mean of the three values. Data were analyzed by analysis of variance (ANOVA), post hoc Bonferroni test, Pearson's correlation, and regression analysis. The level of significance was set at p<0.05 in all analyses. RESULTS: PSV increased from 26.3 to 57.7 cm/s in the MCA between the 22nd and the 38th week of gestation (p<0.05). In the SRA and in the IRA, PSV increased between the 22nd and 34th week of gestation, from 74.6 and 59.0 cm/s to 106.0 and 86.6 cm/s, respectively (p<0.05). In the UA, PSV increased between the 22nd and the 34th week of gestation, but decreased from 55.5 to 46.2 cm/s between the 34th and the 38th week of gestation. In the MCA, the RI was lower in the 22nd (0.81) and 38th week of gestation (0.75) and higher (0.85) in the 26th week (p<0.05). In the SRA, the RI values were stable in all weeks and in the IRA they were stable in most weeks (p>0.05). In the UA, RI decreased from 0.69 to 0.56 between the 22nd and 38th week of gestation (p<0.05). CONCLUSION: in normal fetuses, in the second half of gestation PSV increased in the MCA, SRA and IRA, decreasing in the UA between the 34th and 38th week of gestation. RI was lower in the 22nd and 38th weeks of gestation in the MCA, decreased between the 22nd and the 38th week in the UA, and was constant in most of the gestational weeks in the SRA and IRA.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2005;27(6):323-330
DOI 10.1590/S0100-72032005000600006
PURPOSE: to determine the validity of uterine artery Doppler velocimetry for the prediction of pregnancy complications in a population of low-risk nulliparae. SUBJECTS: a prospective study was conducted on 45 patients in their first pregnancy with no history of chronic diseases. Uterine artery Doppler velocimetry was performed between 24 and 26 weeks, with the determination of resistance index (RI), pulsatility index (PI), S/D ratio, and the presence or absence of incisure in the flow velocity wave. Data were analyzed by the Mann-Whitney test for non-parametric samples, and the Fisher exact test was used in the evaluation of the qualitative parameters. RESULTS: pregnancy complications were observed in twelve patients, with four cases of preeclampsia, one case of small for gestational age newborn (SGA NB), one case of SGA NB + preterm delivery (PTD), three cases of PTD, one case of fetal centralization, and two cases of presence of thick meconium in the amniotic fluid at the time of pregnancy resolution. We noted that RI (median 0.56 x 0.68), PI (median 0.98 x 1.29) and S/D ratio (median 2.2 x 2.9) were higher at the examination performed between 24 and 26 weeks in patients with complications and did not differ in preeclampsia and SGA cases. The presence of bilateral incisure showed 100 and 90% sensitivity, 60.2 and 62.5% specificity, 29.4 and 42,9% positive predictive value (PPV), and 100 and 95.2% negative predictive value (NPV) for the detection of preeclampsia or SGA and of any complication of pregnancy, respectively. An altered Doppler showed 83.3 and 83.3% sensitivity, 69.7 and 69.7% specificity, 33.3 and 50.0% PPV, and 95.8 and 92.0% NPV for the detection of preeclampsia or SGA and of any complication of pregnancy, respectively. CONCLUSION: high impedance indices and the presence of a bilateral incisure in the uterine arteries between 24 and 26 weeks of pregnancy seem to be good predictors of pregnancy and perinatal complications.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2005;27(6):323-330
DOI 10.1590/S0100-72032005000600006
PURPOSE: to determine the validity of uterine artery Doppler velocimetry for the prediction of pregnancy complications in a population of low-risk nulliparae. SUBJECTS: a prospective study was conducted on 45 patients in their first pregnancy with no history of chronic diseases. Uterine artery Doppler velocimetry was performed between 24 and 26 weeks, with the determination of resistance index (RI), pulsatility index (PI), S/D ratio, and the presence or absence of incisure in the flow velocity wave. Data were analyzed by the Mann-Whitney test for non-parametric samples, and the Fisher exact test was used in the evaluation of the qualitative parameters. RESULTS: pregnancy complications were observed in twelve patients, with four cases of preeclampsia, one case of small for gestational age newborn (SGA NB), one case of SGA NB + preterm delivery (PTD), three cases of PTD, one case of fetal centralization, and two cases of presence of thick meconium in the amniotic fluid at the time of pregnancy resolution. We noted that RI (median 0.56 x 0.68), PI (median 0.98 x 1.29) and S/D ratio (median 2.2 x 2.9) were higher at the examination performed between 24 and 26 weeks in patients with complications and did not differ in preeclampsia and SGA cases. The presence of bilateral incisure showed 100 and 90% sensitivity, 60.2 and 62.5% specificity, 29.4 and 42,9% positive predictive value (PPV), and 100 and 95.2% negative predictive value (NPV) for the detection of preeclampsia or SGA and of any complication of pregnancy, respectively. An altered Doppler showed 83.3 and 83.3% sensitivity, 69.7 and 69.7% specificity, 33.3 and 50.0% PPV, and 95.8 and 92.0% NPV for the detection of preeclampsia or SGA and of any complication of pregnancy, respectively. CONCLUSION: high impedance indices and the presence of a bilateral incisure in the uterine arteries between 24 and 26 weeks of pregnancy seem to be good predictors of pregnancy and perinatal complications.
