Doppler RI Research Articles

Postnatal Cerebral Hemodynamics and Placental Vascular Malperfusion Lesions in Neonates With Congenital Heart Disease

BackgroundNeonates with congenital heart disease (CHD) have smaller brain volume at birth. High rates of placental vascular malperfusion lesions may play a role in disrupted brain development. MethodsThis is a single-center retrospective cohort study of infants born between 2010 and 2019 who were diagnosed with a major cardiac defect requiring surgery in the first year of life. Doppler ultrasound RI of the middle cerebral artery (MCA) and anterior cerebral artery were calculated within the first 72 hours of life. Placentas were evaluated using a standardized approach. ResultsOver the study period, there were 52 patients with hypoplastic left heart syndrome (HLHS), 22 with single-ventricle right ventricular outflow tract obstruction (SV-RVOTO), 75 with a two-ventricle cardiac defect (2V), and 25 with transposition of the great arteries (TGA). MCA Doppler RI were significantly higher for all subgroups of CHD compared with control subjects (0.68 ± 0.11 in control subjects compared with 0.78 ± 0.13 in HLHS, P = 0.03; 0.77 ± 0.10 in SV-RVOTO, P = 0.002; 0.78 ± 0.13 in 2V, P = 0.03; and 0.80 ± 0.14 in TGA; P = 0.001) with the highest average MCA RI in the TGA group. In subgroup analyses, placental fetal vascular malperfusion in the 2V group was associated with higher MCA RI, but this relationship was not present in other subgroups, nor in regards to maternal vascular malperfusion. ConclusionsMajor forms of CHD are associated with significantly higher cerebral artery RI postnatally, but placental vascular malperfusion lesions may not contribute to this hemodynamic adaptation.

Doppler velocity of fetal renal arteries in case of oligohydramnios

Background: Oligohydramnios is a relatively common complication of pregnancy and such a case is often encountered in clinical practice. Oligohydramnios is often to describe pregnancies with AFI <5 and borderline/ low normal amniotic fluid volume to describe pregnancies with AFI 5 to 8 (4) Alternatively, some clinicians prefer the single vertical pocket (SVP) with severe oligohydramnios defined as SVP less than 1 and mild oligohydramnios defined as SVP 1 to 2 Aim of this current study sought to determine the relation of fetal renal artery Doppler with normal pregnancies and pregnancies complicated by oligohydramnios.Methods: Sample size was 50 patients in the 2nd trimester; they subdivided into two groups based on the amount of the amniotic fluid as follow: Group I: Control group (AFI 5-25) N = 25 cases.Group II: Oligohydramnios group (AFI less than 5) N = 25 cases.All patients in this study subjected to the following:Ultrasound study: Measurement of fetal biometry, Detection of congenital malformation. And Amniotic fluid index measurement. Doppler study: Renal artery (RA) and Umbilical artery (UA).Results: There was statistically significant difference between groups according to Renal and umbilical artery Doppler indices PI & RI in Gestational Age 26 weeks, statistically significant difference over the periods through renal artery Doppler indices RI, statistically significant difference over the periods through umbilical artery Doppler indices PI in each group and Renal Artery PI Which was 2.681, with sensitivity of 44.6% specificity of 53% with diagnostic accuracy of 47%, (p-value >0.05 NS). Renal Artery RI Which was 0.989, with sensitivity of 43.5% specificity of 43% with diagnostic accuracy of 33%, (p-value >0.05 NS). Umbilical Artery PI Which was 1.044, with sensitivity of 42.1% specificity of 39.5% with diagnostic accuracy of 29.7%, (p-value >0.05 NS). Umbilical Artery RI Which was 0.645, with sensitivity of 48.5% specificity of 42.1% with diagnostic accuracy of 41.6%, (p-value >0.05 NS). Conclusions: We recommend introducing renal artery resistance index as auxiliary ante partum test for women with Amniotic fluid abnormalities in addition to other ante partum fetal wellbeing tests to predict fetuses at risk of hypoxia.

Uterine Artery Doppler and Placental Morphological Features as Predictors of Peripartum Complications in Placenta Previa and Placenta Previa Accreta

Background: Placenta accreta is becoming an increasingly common complication of pregnancy. Placenta accreta originates from abnormal trophoblast invasion. Objective: to assess if uterine artery Doppler and Placental Morphological Features could be predictors of maternal and fetal outcome in pregnancies complicated with placenta previa and placenta previa accreta. Subjects and methods: This study included 80 pregnant women of which they were divided into 3 groups. The first group included 40 pregnant women of normal pregnancies, 2nd one included 20 pregnant women with placenta previa and the 3rd one included 20 pregnant women with suspected placenta previa accreta by ultrasound. Abdominal ultrasound and uterine artery Doppler were done in a week before delivery. Results: There was a direct relationship between presence of lacunae especially high grade, placental vascularity (abnormal) and the mean values of uterine artery PI, RI and presence of peripartum maternal and fetal complications. Conclusion: the gray scale and color Doppler ultrasound have a high diagnostic value in the diagnosis by certain placental morphological features, Including loss of retro-placetal clear zone, thinning of myometrial thickness, Intraplacental lacunae, Intraplacental vascularity and exophytic mass into bladder space. Ultrasound is helpful and non-invasive tool in prediction of maternal and fetal outcome. High grade of placental lacunae and abnormal placental vascularity were highly associated with maternal and fetal complications. Uterine artery Doppler PI and RI is also useful in prediction of maternal complications and fetal complications of placenta previa and placenta previa accreta.

Diagnosis of Placenta Accreta by Uterine Artery Doppler Velicometry in Patients with Placenta Previa

Background: Placenta accreta occurs in the complete or partial absence of the decidua basalis. Women with previous cesarean delivery or placenta previa are known to be at greater risk of placenta accreta. Objectives: to evaluate ultrasound accuracy in diagnosing placenta accreta and its variants and to detect the potential value of uterine artery Doppler in diagnosing placenta accreta and to assess the impact of antenatal diagnosis in Egyptian population. Patients and Methods: This prospective study was conducted on (100) pregnant women diagnosed as placenta previa by ultrasonography and were candidates for either emergency or elective repeated CS or hysterectomy (if the diagnosis of placenta accreta is confirmed). All these patients were randomly selected from the Obstetrics Clinic at Beni-Suef General Hospital during their 3rd trimester. The study was approved by the medical ethics committee of Al-Azhar University academic and ethical committee and a written informed consent was obtained from all patients. Results: The results obtained from this study indicated no statistically significant differences regarding the mean values of uterine artery Doppler PI and RI between cases of placenta accreta and non accreta (p value =.078 & 0.58 respectively) in correlation with histopathological assessment. Our results showed no statistically significant correlation regarding mean values of uterine artery Doppler PI and RI between cases of placenta accreta and placenta non accreta (p values = 0.341, 0.953 respectively) in correlation with intra-operative assessment. Conclusion: Several ultrasound criteria can be used in diagnosis of placenta accreta, as this study showed their high accuracy. They include loss of retroplacental clear zone, presence of abnormal placental lacunae, myometrial thinning and utero-vesical hypervascularity. On the other hand, both loss of retroplacental clear zone, abnormal placental lacunae can predict which patient will mostly have CS hysterectomy.

Diagnosis of Placenta Accreta by Uterine Artery Doppler Velicometry in Patients with Placenta Previa

Background: Placenta accreta occurs in the complete or partial absence of the decidua basalis. Women with previous cesarean delivery or placenta previa are known to be at greater risk of placenta accreta. Objectives: to evaluate ultrasound accuracy in diagnosing placenta accreta and its variants and to detect the potential value of uterine artery Doppler in diagnosing placenta accreta and to assess the impact of antenatal diagnosis in Egyptian population. Patients and Methods: This prospective study was conducted on (100) pregnant women diagnosed as placenta previa by ultrasonography and were candidates for either emergency or elective repeated CS or hysterectomy (if the diagnosis of placenta accreta is confirmed). All these patients were randomly selected from the Obstetrics Clinic at Beni-Suef General Hospital during their 3rd trimester. The study was approved by the medical ethics committee of Al-Azhar University academic and ethical committee and a written informed consent was obtained from all patients. Results: The results obtained from this study indicated no statistically significant differences regarding the mean values of uterine artery Doppler PI and RI between cases of placenta accreta and non accreta (p value =.078 & 0.58 respectively) in correlation with histopathological assessment. Our results showed no statistically significant correlation regarding mean values of uterine artery Doppler PI and RI between cases of placenta accreta and placenta non accreta (p values = 0.341, 0.953 respectively) in correlation with intra-operative assessment. Conclusion: Several ultrasound criteria can be used in diagnosis of placenta accreta, as this study showed their high accuracy. They include loss of retroplacental clear zone, presence of abnormal placental lacunae, myometrial thinning and utero-vesical hypervascularity. On the other hand, both loss of retroplacental clear zone, abnormal placental lacunae can predict which patient will mostly have CS hysterectomy.

Hypertensive disorders of pregnancy associated with adverse pregnant outcomes in patients with systemic lupus erythematosus: a multicenter retrospective study.

Hypertension disorders in pregnancy (HDP) were common complications in women with systemic lupus erythematosus (SLE). However, the impact of HDP and the measures to prevent HDP-related fetal adverse pregnancy outcomes (APOs) remained to be explored. A multicenter retrospective study of 342 pregnant women with SLE was performed. Variables related to SLE and APOs were recorded. Fetal development was evaluated by umbilical artery Doppler ultrasonography. HDP was diagnosed in 45 (13.2%) patients, including pre-eclampsia in 42 and gestational hypertension in 3. Patients with HDP had higher incidence of preterm birth (71.1% vs 20.9%, P < 0.001), intrauterine growth retardation (IUGR) (37.8% vs 11.8%, P < 0.001), low-birth-weight infants (62.2% vs 17.2%, P < 0.001), and very-low-birth-weight infants (37.8% vs 2.7%, P < 0.001), compared with lupus patients without HDP. A total of 35 (77.8%) HDP patients had disease activation during pregnancy. All the events occurred during the second and third trimesters, mainly presenting as moderate-to-high activity (65.7%). Active disease [odds ratios (OR) = 3.9, 95% confidential interval (CI) 1.5-9.7, P = 0.004] and positive anticardiolipin (aCL) antibody (OR = 7.6, 95% CI 2.7-18.6, P < 0.001) were independent risk factors for HDP in lupus patients. Doppler RI and S/D ratio predicted APOs in patients with HDP. The optimal cut-off values for RI and S/D ratio were 0.7 (sensitivity 48.1%, specificity 53.3%) and 3.4 (sensitivity 66.7%, specificity 100%), respectively. HDP was a common pregnant complication and caused various fetal and maternal adverse outcomes in patients with SLE. Umbilical artery Doppler ultrasonography was effective in predicting fetal APOs in lupus patients with HDP.Key Points• HDP induced preterm birth, IUGR, low-birth-weight infants, and very-low-birth-weight infants in patients with SLE.• HDP led to lupus activation during the second and third trimesters.• Disease activation and aCL positivity were predictors for HDP.• RI and S/D ratio from umbilical artery Doppler predicted APOs in patients with HDP.

Early detection with renal Doppler resistive index measurements of hemorrhagic shock in polytrauma patients

Background: Poly trauma is a major cause of morbidity and mortality in both developed and developing countries. The aim was to investigate whether renal Doppler RI changes occur early with posttraumatic bleeding and whether the renal Doppler RI may enable accurate prediction of occult hypoperfusion and thus be predictive of the development of hemorrhagic shock in polytrauma patients.Methods: It was a prospective study involving patients admitted in the causality and evaluated by radiology department. Study was done in a period of 6 months from June 2016-December 2016. Renal Doppler RI was measured in 48 hemodynamically stable adult patients admitted in emergency because of polytrauma.Results: 26 patients developed hemorrhagic shock, and 22 did not. Hemorrhagic shock group, as compared with the nonhemorrhagic shock group, had higher renal Doppler RI (mean, 0.79±0.11 [standard deviation] vs 0.61±0.2; P&lt;0.01), injury severity score (mean, 33±12 vs 25±9; P&lt;0.01), and standard base excess (mean, -4.0mEq/L±4 vs 1mEq/L±3; P≤0.05) values. At logistic regression analysis, a renal Doppler RI greater than 0.9 was the only independent risk factor for progression to hemorrhagic shock (P&lt;0.001).Conclusions: Renal Doppler RI measurement may represent a clinically useful non-invasive method for the early detection of occult hemorrhagic shock.

Decidual natural killer cell receptor expression is altered in pregnancies with impaired vascular remodeling and a higher risk of pre-eclampsia.

During pregnancy, a specialized type of NK cell accumulates in the lining of the uterus (decidua) and interacts with semiallogeneic fetal trophoblast cells. dNK cells are functionally and phenotypically distinct from PB NK and are implicated in regulation of trophoblast transformation of the uterine spiral arteries, which if inadequately performed, can result in pregnancy disorders. Here, we have used uterine artery Doppler RI in the first trimester of pregnancy as a proxy measure of the extent of transformation of the spiral arteries to identify pregnancies with a high RI, indicative of impaired spiral artery remodeling. We have used flow cytometry to examine dNK cells isolated from these pregnancies compared with those from pregnancies with a normal RI. We report a reduction in the proportion of dNK cells from high RI pregnancies expressing KIR2DL/S1,3,5 and LILRB1, receptors for HLA-C and HLA-G on trophoblast. Decreased LILRB1 expression in the decidua was examined by receptor blocking in trophoblast coculture and altered dNK expression of the cytokines CXCL10 and TNF-α, which regulate trophoblast behavior. These results indicate that dNK cells from high RI pregnancies may display altered interactions with trophoblast via decreased expression of HLA-binding cell-surface receptors, impacting on successful transformation of the uterus for pregnancy.

Fetal inflow hydrostatic pressure measurements in the ex-vivo perfused placenta correlate with umbilical artery Doppler RI and PI values

Fetal inflow hydrostatic pressure measurements in the ex-vivo perfused placenta correlate with umbilical artery Doppler RI and PI values

Splenic Doppler Resistive Index for Early Detection of Occult Hemorrhagic Shock After Polytrauma in Adult Patients

The objective of this study was to evaluate whether direct assessment of splenic circulation by splenic Doppler resistive index (Doppler RI) is a clinically useful noninvasive method for an early detection of occult hemorrhagic shock after polytrauma in adult patients. Splenic Doppler RI was measured in 49 hemodynamically stable adult patients admitted to the emergency department because of polytrauma. Renal Doppler RI was also determined in 20 patients. Spleen size, Injury Severity Score, systolic blood pressure, heart rate, blood lactate, standard base excess, pH, hemoglobin, and inferior vena cava diameter values were recorded at admission and at 24 h. Patients were grouped according to whether signs of hemorrhagic shock did (n = 22) or did not (n = 27) occur within the first 24 h from admission. Patients who developed hemorrhagic shock had significantly higher splenic and renal Doppler RI, higher Injury Severity Score, and lower standard base excess at admission. By multivariate logistic regression, splenic Doppler RI resulted to be a predictor of hemorrhagic shock development within the first 24 h from admission. Splenic Doppler RI may represent a clinically useful noninvasive method for early detection of occult hemorrhagic shock and persistent occult hypoperfusion after polytrauma in adult patients.

OP37.10: Ophthalmic artery Doppler in pregnant women with systemic lupus erythematosus

The Doppler changes and pregnancy outcomes were analyzed with independent sample t-test, Fisher’s exact test and Pearson’s correlation using the SPSS statistical software (version 12.0; SPSS Inc, Chicago, IL). Results: Twenty one patients with myomas and 30 normal patients were enrolled in this study. The RI and S/D ratio of the uterine artery on both sides were not differ in the myoma group and in control group (P = 0.42, P = 0.15, P = 0.29, P = 0.12, in Right RI, Left RI, Right S/D, Left S/D, respectively). In patients with right side dominant myoma and with left side dominant myoma, the uterine artery Doppler RI and S/D ratio were not differ significantly (P = 0.65, P = 0.22, P = 0.39, P = 0.28, in Right RI, Left RI, Right S/D, Left S/D, respectively). Age is significantly higher in the myoma group (P = 0.03), but there were no differences in gestational age at birth, birth weight, five minute APGAR score, Cesarean section due to fetal distress and neonatal intensive unit care (P = 0.62, P = 0.20, P = 0.08, P = 0.99, P = 0.10, respectively). Conclusions: According to this study, the presence of myoma as well as the location and the size of myoma didn’t change the uterine artery Doppler velocimetry and didn’t affect the pregnancy outcome. Cesarean section or early delivery due to large myoma could be reserved in prenatal management. Further study with a larger study population would be needed for better outcome.

0470: Ultrasound in Crohns Disease

High-resolution ultrasonography has greatly improved the diagnostic potential of ultrasound in the assessment of inflammatory bowel disease. Ultrasonography is not only a method used by radiologists, but also a clinical tool that can be applied to evaluate patients with Crohn's disease: both for bed-side tentative diagnosis, pre-operative scanning, and for out-patient follow-up. This lecture reviews some of the principles, common findings and methods that can be used in ultrasonographic scanning of the GI tract in patients with Crohn's disease. Ultrasound of the GI tract has proved to be useful as an imaging modality in patients with symptoms or clinical signs that indicate inflammatory bowel disorder as well as for assessing the anatomical extension of Crohn's lesions at primary diagnosis. Mb. Crohn often starts with symptoms like abdominal pain, diarrhoea or weight loss. Ultrasonography is a very relevant method to rule out different causes of these symptoms and to detect changes compatible with Crohn's disease. A normal bowel wall is considered to have a wall thickness below 2-4mm, depending on the actual localisation. Typical ultrasound findings in Crohn's disease are: Increased GI-wall thickness most often seen in the distal ileum, dilated bowel loops, ulcerations or fistulas, abscesses, reduced motility, decreased Resistive Index, and in some cases ascites. In some cases, full endoscopic examination is not possible due to a stenotic GI segment, e.g. of the colon or pyloric ulceration leading to gastric retention. In such circumstances, transabdominal ultrasound can image the more central part of the intestines and give valuable information about the length of the stenotic part. Ultrasonic determination of the extent of the GI-wall affection will also aid in distinguishing between ulcerative colitis and Crohn's disease. Another indication is the ambulant follow-up of patients who have established Crohn's disease. High-frequency ultrasonography may play a key role in the detection of luminal and mesentery complications or for the evaluation of disease extension during a clinical flare-up. The patients can act as their own controls over time and the effect of treatment can be monitored by ultrasonography. The role of bowel ultrasound in the assessment of disease activity is controversial, but the use of Doppler RI and i.v. contrast agents has the potential to differentiate inflammatory from fibrotic intestinal strictures. Contrast-enhanced power Doppler ultrasound has high sensitivity and specificity in the detection and evaluation of inflammatory abdominal masses associated with Crohn's disease, and compares favourably with computed tomography. The spatial resolution and sensitivity of contrast-enhanced power Doppler ultrasound enables the detection of small inflammatory abdominal masses. The absence of radiation dose to the patient allows multiple and serial examinations to be undertaken. In conclusion, ultrasonography is a very useful clinical tool in the management of patients with Crohn's disease. New ultrasound technologies, such intravenous contrast agents, advanced Doppler methods, and elastography may further increase the diagnostic capability of GI ultrasonography.

Three-dimensional ultrasound and three-dimensional power Doppler in the assessment of ovarian tumors

Objective To determine preoperative method that predicts nature of ovarian tumors. Methods Fifty patients with complex pelvic masses assessed preoperatively with two-dimensional ultrasound (2DUS), two-dimensional power Doppler (2DPD), three-dimensional ultrasound (3DUS), three-dimensional power Doppler (3DPD), color Doppler. Results All patients underwent exploration, 19 (38%) had benign tumors, 31 (62%) had ovarian cancer. 2DUS identified 29 cases suspicious for malignancy giving sensitivity, specificity, PPV and accuracy of 80%, 78%, 86%, and 80%. 2DUS with 2DPD identified 28 suspicious cases giving sensitivity, specificity, PPV and accuracy of 80%, 84%, 89%, and 82%. 3DUS identified 31 suspicious cases including 28 cancers giving sensitivity, specificity, PPV and accuracy of 90%, 84%, 90%, and 88%. 3DUS with 3DPD, identified 34 suspicious cases including all 31 cancers giving sensitivity, specificity, PPV and accuracy of 100%, 84%, 91%, and 94%. Color Doppler RI of 0.48 identified 28 cases of 31 cancers giving sensitivity of 90%. Conclusion Evaluation by 3DUS with 3DPD improves diagnostic accuracy of ovarian tumors.

Vascular endothelial growth factor and insulin-like growth factor-1 in polycystic ovary syndrome and their relation to ovarian blood flow

Objectives: (1) To determine the serum levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) in women with polycystic ovary syndrome (PCOS). (2) To study Doppler blood flow changes within the ovarian stroma of women with PCOS. (3) To evaluate the relationship between VEGF and IGF-1 and Doppler indices as well as hormonal profile. Setting: Department of Obstetrics and Gynecology, and Department of Biochemistry, Faculty of Medicine, Assiut University, Egypt. Design: Cross-sectional study. Patients and methods: Fifty infertile women with PCOS diagnosed by ultrasound examination and a history of oligomenorrhea, hirsutism and obesity were studied. Serum levels of vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1) and hormonal profile were measured. Doppler blood flow velocity waveforms analysis in both right and left intraovarian arteries was done. Twenty healthy and fertile women with regular menstrual cycles served as a comparison group were similarly studied at the third day of the cycle. Results: The serum levels of VEGF, IGF-1 (4.79 ± 0.91, 253.15 ± 70.07 versus 2.39 ± 0.42, 186.65 ± 42.7) were significantly elevated ( P < 0.001 and P < 0.01, respectively) in women with PCOS compared with control. Doppler indices, PI (2.01 ± 0.77, 2.66 ± 1.00 versus 2.98 ± 0.77, 3.75 ± 0.98) and RI (0.77 ± 0.12, 0.82 ± 0.09 versus 0.87 ± 0.09, 0.89 ± 0.09) in both right and left intraovarian vessels were significantly lower in the patients than controls. The VEGF and IGF-1 levels were negatively correlated with RI and PI in the uterine and intraovarian arteries. VEGF level was positively correlated with IGF-1 ( r = 0.41, P < 0.05) in women with PCOS. Conclusions: Higher serum levels of VEGF and IGF-1 in PCOS women may be related to the increased vascularity that underlies the increased blood flow demonstrated by Doppler blood flow measurements in these women.

Understanding the Doppler RI: impact of renal arterial distensibility on the RI in a hydronephrotic ex vivo rabbit kidney model.

The aim of this study was to evaluate the influence of elevated ureteral pressure on renal arterial distention, and thereby on the Doppler resistive index. Seven isolated rabbit kidneys were subjected to a pulsatile perfusion while the renal pelvis was pressurized via the ureter. Renal vascular pressure, flow, resistance (pressure/flow) and conductance (flow/pressure) were compared to simultaneous resistive index measurements using linear regression analysis. Changes in the Conductance Index (systolic conductance - diastolic conductance/systolic conductance) were likewise compared to the resistive index. Elevations in ureteral pressure were significantly correlated with (1) increased resistive index values, (2) increased mean renal vascular resistance, (3) decreased mean conductance, and (4) increased conductance index values (for all correlations P < 0.05). The increases in the resistive index correlated significantly with increases in the conductance index. This study shows that elevated ureteral pressure, likely acting via interstitial pressure, diminishes the conductance of the renal vascular bed. Because this effect is more dramatic at diastole, the cyclic patterns of flow are altered, resulting in elevated resistive index values. The results indicate the importance of the interaction between vascular distensibility and pulsatile flow, rather than overall mean renal vascular resistance, in determining resistive index values.

Understanding the Doppler RI: impact of renal arterial distensibility on the RI in a hydronephrotic ex vivo rabbit kidney model.

The aim of this study was to evaluate the influence of elevated ureteral pressure on renal arterial distention, and thereby on the Doppler resistive index. Seven isolated rabbit kidneys were subjected to a pulsatile perfusion while the renal pelvis was pressurized via the ureter. Renal vascular pressure, flow, resistance (pressure/flow) and conductance (flow/pressure) were compared to simultaneous resistive index measurements using linear regression analysis. Changes in the Conductance Index (systolic conductance - diastolic conductance/systolic conductance) were likewise compared to the resistive index. Elevations in ureteral pressure were significantly correlated with (1) increased resistive index values, (2) increased mean renal vascular resistance, (3) decreased mean conductance, and (4) increased conductance index values (for all correlations P < 0.05). The increases in the resistive index correlated significantly with increases in the conductance index. This study shows that elevated ureteral pressure, likely acting via interstitial pressure, diminishes the conductance of the renal vascular bed. Because this effect is more dramatic at diastole, the cyclic patterns of flow are altered, resulting in elevated resistive index values. The results indicate the importance of the interaction between vascular distensibility and pulsatile flow, rather than overall mean renal vascular resistance, in determining resistive index values.

Placental vessel morphometry in growth retardation and increased resistance of the umbilical artery Doppler flow.

To study the tertiary-stem villi vessel lumen and wall thickness of placenta in pregnancy complicated with placental insufficiency and intrauterine growth retardation (IUGR), its correlation with the umbilical artery Doppler flow study, and compare with normal and non-IUGR pregnancies. Placentas from 45 deliveries (between 28 and 38 weeks) were collected for morphometric study of the tertiary-stem villi vessels. Each pregnancy had clinical suspicion of IUGR and was confirmed by serial ultrasound biometry, HC/AC ratio, and had abnormal umbilical artery Doppler velocimetry (RI). Each placenta was weighed after trimming of the membrane and the cord. Sections of the placenta (4 micron) were stained with hematoxylin and eosin and periodic acid-Schiff reagents. Tertiary-stem villi vessels were identified under a microscope (x40) and morphometric study was performed. Inner and outer circumferences (2.pi.r) were measured, radii (r) were calculated, and vessel wall thickness was determined (outer r - inner r). These findings were compared with the findings from 78 placentas from normal pregnancies (between 28-40 weeks) and 27 placentas from pregnancies with medical complications without IUGR (non-IUGR) and with normal Doppler velocimetry (between 33 and 38 weeks). Weight of placentas were significantly (P < 0.005) lower in IUGR than the normal and non-IUGR groups. The vessel wall thickness was significantly (P < 0.0001) increased in IUGR group (mean 21.17 +/- 3.16 micron [SD]) compared to normal and non-IUGR groups (mean 13.19 +/- 1.66 micron). With advancing gestational age, the thicknesses of vessel walls in all groups were significantly (P < 0.001) decreased. There was significant (P < 0.001) decrease in lumen circumference in the IUGR group (mean 173 +/- 31 micron) compared to normal and non-IUGR groups (mean 69 +/- 23 micron). Significant (P < 0.001) correlation was observed between the thickness of a vessel wall and the increase in Doppler RI. Pregnancies with growth retardation are associated with smaller placentas, increase in the thickness of tertiary-stem villi vessel wall, and decrease in lumen circumference. These changes are associated with an increase in the resistance index of the umbilical artery Doppler flow velocimetry.

Adjusted resistive index: a method to estimate rapidly renal blood flow: preliminary validation in hypertensives

The Doppler RI, measured in a blinded fashion, was correlated with RBF, RVR, and GFR calculated by simultaneous clearance measurements. Nine hypertensive patients were studied weekly while receiving increasing doses of the vasodilator minoxidil. In 36 studies, RI was significantly correlated with RBF (r = -0.42) but not with RVR or GFR. When RI values were adjusted for ERV, correlations strikingly improved and were further improved by adjustment for pulse pressure. The ARI allowed semiquantitative predictions of RBF and RVR more accurately than blood urea nitrogen or serum creatinine levels. Correlation with GFR was weak.