Color Doppler Ultrasound Measurements Research Articles

Changes of testicular blood flow after vasectomy: Assessment by color Doppler ultrasound resistive index measurement

Objective: The objectives of this study were to evaluate the testicular blood flow in patients after vasectomy by use of color Doppler ultrasound resistive index measurement.

Hemodynamic responses of the caudal artery to toxic tall fescue in beef heifers1

Color Doppler ultrasonography was used to compare blood flow characteristics in the caudal artery of heifers fed diets with endophyte (Neotyphodium coenophialum) infected (E+) or noninfected (E-) tall fescue seed. Eighteen crossbred (Angus x Brangus) heifers were assigned to 6 pens and were fed chopped alfalfa hay for 5 d and chopped alfalfa hay plus a concentrate that contained E-tall fescue seed for 9 d during an adjustment period. An 11-d experimental period followed, with animals in 3 pens fed chopped alfalfa hay plus a concentrate with E+ seed and those in the other 3 pens fed chopped hay plus concentrate with E E- seed. Color Doppler ultrasound measurements (caudal artery area, peak systolic velocity, end diastolic velocity, mean velocity, heart rate, stroke volume, and flow rate) and serum prolactin were monitored during the adjustment (baseline measures) and during the experimental period. Three baseline measures were collected on d 3, 5, and 6 during the adjustment period for comparison to post E+ seed exposure. Statistical analyses compared the proportionate differences between baseline and response at 4, 28, 52, 76, 100, 172, and 268 h from initial feeding of E+ seed. Serum prolactin concentrations on both diets were lower (P <0.001) than baseline beginning at 4 h from the start of the experimental period. However, trends in serum prolactin concentrations for heifers on the E- diet suggested ambient temperature was affecting these concentrations. Caudal artery area in E+ heifers had declined (P <0.10) from baseline by 4 h and was consistently lower (P <0.05) for the remainder of the period. Heart rates for E+ heifers were lower than the baseline rate from 4 (P <0.10) to 100 (P <0.001) h, but were similar (P >0.10) to the baseline for 172 and 268 h measures. Blood flow in E+ heifers was consistently lower than the baseline from 4 (P <0.05) to 172 (P <0.001) h, but was similar to the baseline at 268 h when heart rate was similar to the baseline rate. Caudal artery areas for the E- diet were similar to baseline areas except at 100 h when it was greater than baseline. Heart rates and flow rates for E- heifers did not differ (P >0.10) from baseline measures during the experimental period. Results indicated that onset of toxicosis was within 4 h of cattle exposure to E+ tall fescue and is related to vasoconstriction and reduction in heart rate.

Assessment of renal function with color Doppler ultrasound in autosomal dominant polycystic kidney disease.

Measurement of renal blood flow by color Doppler ultrasound is useful for assessment of renal function in a variety of renal disorders. In autosomal dominant polycystic kidney disease (ADPKD), however, it might be difficult to visualize interlobar arteries because of deformity of renal structure. To evaluate the usefulness of color Doppler in ADPKD, parameters determined by blood flow examination were compared with the results of ordinal renal function tests. Twenty-one patients with ADPKD were examined by color Doppler ultrasound measurement. In each patient, 10 interlobar arteries in both kidneys were investigated. Minimum blood flow velocity (Vmin), maximum blood flow velocity (Vmax), mean blood flow velocity (Vmean), acceleration, resistive index and pulsatility index were measured in relation to the results of creatinine clearance, serum creatinine, blood urea nitrogen and 15 and 120 min values of the phenolsulfonphthalein test. In all patients, interlobar arteries were able to be visualized and blood-flow profile was measured. Although variations of Vmin, Vmax, Vmean and acceleration were relatively large, the resistive index and pulsatility index varied little in each kidney. Mean values of Vmin (P < 0.005), Vmean (P < 0.05), resistive index (P < 0.005) and pulsatility index (P < 0.005) were well correlated to creatinine clearance with statistical significance. In ADPKD, color Doppler ultrasound measurement is a useful method for assessment of renal function and could be used for monitoring the dynamic state of renal blood flow as a non-invasive technique.

Uteroplacental circulation in patients with first-trimester threatened abortion

Objective: To assess uteroplacental circulation in patients with first-trimester threatened abortion with a living embryo. Design: Prospective, cross-sectional study. Setting: Tertiary care university hospital. Patient(s): Forty-nine patients with first-trimester threatened abortion and a living embryo and 129 women with singleton, low-risk, normally developing first-trimester pregnancies recruited as controls. Intervention(s): Transvaginal color Doppler ultrasound measurement of the peak systolic velocity and pulsatility index of the uterine arteries and the spiral arteries. Main Outcome Measure(s): Uteroplacental blood flow and pregnancy outcome. Result(s): There was a significant relation between gestational age and the peak systolic velocity and pulsatility index in the uterine arteries and between gestational age and the peak systolic velocity and pulsatility index in the spiral arteries in controls. There were no differences in any Doppler parameter assessed between the study group and the controls, even in those pregnancies that ended in spontaneous abortion. Conclusion(s): No apparent alteration occurs in the early uteroplacental circulation in patients with threatened abortion with a living embryo. The use of transvaginal color Doppler ultrasound is not helpful for predicting pregnancy outcome in these cases.

Importance of the Renal Resistive Index in Children Suffering from Vesicoureteral Reflux

Objective: in our study, we wanted to assess changes and values of the renal resistive index (RI) in children with vesicoureteral reflux (VUR) using color Doppler ultrasound (CDUS) techniques. Methods: We investigated 92 kidney units in 46 children (mean age 6 ± 4 years) with VUR by means of CDUS. The RI was measured at the level of the interlobar and/or arcuate arteries using a color Doppler unit Acuson 128 XP/10. The CDUS findings were correlated with those obtained using standard renal scintigraphy. Results: Children with VUR grades I–III showed a RI of 0.6 ± 0.07, whereas patients suffering from VUR grades IV and V demonstrated a significantly increased RI of 0.77 ± 0.07 (p < 0.0001). The correlation of the CDUS measurements with the scintigraphic findings revealed a positive correlation coefficient of r² = 0.61. Conclusions: CDUS seems to be a helpful, radiation-free, noninvasive, and inexpensive tool in children with VUR, demonstrating a significant change in the RI especially in high-grade reflux. Moreover, the RI findings represent a good correlation with standard renal scintigraphy. Therefore, CDUS with assessment of the RI allows a perfect follow-up study of affected children.

The effects of carotid endarterectomy on ocular haemodynamics.

To determine the profile of blood flow velocities and resistive indices in the ocular vessels of patients with atherosclerotic carotid disease and characterise the effect of endarterectomy on these parameters. Following a preliminary study on healthy volunteers, ophthalmic colour Doppler ultrasound examinations were performed on 27 male and 11 female patients with carotid disease. These measurements were compared with central retinal artery perfusion pressures and intraoperative internal carotid artery stump pressures. Significant changes were seen on the endarterectomised side. The peak systolic velocity in the ophthalmic artery, and resistive indices in the ophthalmic artery, central retinal artery and nasal posterior ciliary artery, rose from pre-operative values. No correlation between colour Doppler ultrasound measurements and intraoperative internal carotid artery stump pressures was present. When compared with ophthalmodynamometry readings, a relationship was noted with maximum velocities in the central retinal vein. Carotid endarterectomy alters the haemodynamics in selected vessels of the ocular circulation as measured by colour Doppler ultrasound, but more work is required to determine the clinical utility of this investigative modality.

A Comparison of Compression Ultrasound With Color Doppler Ultrasound for the Diagnosis of Symptomless Postoperative Deep Vein Thrombosis

Despite advances in primary prophylaxis, venous thromboembolism still occurs in a considerable number of high-risk surgical patients. Screening with conventional ultrasound imaging to detect asymptomatic deep vein thrombosis (DVT) has been suggested as a strategy to improve management of such patients, but it is insufficiently sensitive. We evaluated the ability of color Doppler ultrasound to improve the sensitivity of compression ultrasound in the detection of asymptomatic DVT in high-risk orthopedic patients. We prospectively evaluated bilateral compression and color Doppler ultrasound measurements of the entire leg in 204 consecutive patients who underwent elective hip or knee replacement surgery, using contrast venography as the reference test. The sensitivity, specificity, and positive predictive value of the ultrasonography tests were determined. The sensitivity, specificity, and positive predictive value (with 95% confidence intervals [CIs]) of compression ultrasound for the detection of proximal DVT were 60% (39%-81%), 96% (92%-99%), and 71% (48%-89%) respectively. The sensitivity, specificity, and positive predictive value (with 95% CIs) of compression ultrasound for the detection of calf vein thrombosis were 33% (18%-52%), 91% (83%-96%), and 58% (34%-80%), respectively. Color Doppler ultrasonography did not identify any additional proximal or calf vein thrombi to those detected by compression ultrasound alone. The sensitivity for all thrombi was 47% (95% CI, 34%-61%) with a positive predictive value of 65% (95% CI, 48%-79%). Color Doppler ultrasonography has a moderate to low accuracy for the detection of DVT in patients who have had hip and knee replacement surgery. Color Doppler ultrasonography does not increase the detection rate for asymptomatic DVT over compression ultrasound and thus cannot be recommended as a screening test in this setting.

Intraobserver variation in transvaginal Doppler blood flow measurements in benign ovarian tumors.

Intraobserver variation in transvaginal color Doppler ultrasound measurements in ovarian tumors was evaluated in 20 women selected from a group of patients undergoing surgical exploration for an ovarian lesion. Only those cases who were suspected of having a benign ovarian tumor other than a unilocular simple cyst were recruited. Pulsatility index (PI), resistance index (RI), peak systolic velocity (PSV) and time-averaged maximum velocity (TAMXV) were measured from intratumoral arteries in two repeat ultrasound sessions by the same observer. In each session, only two vessels with optimum Doppler signals were investigated. The repeatability of the measurements was studied by calculation of the within-subjects standard deviation (SD), the value below which the difference between the repeat measurements will lie with a probability of 0.95, the coefficient of variation (CV) and the intraclass correlation coefficient (intra-CC). The CV was 15% for the PI, 13% for the RI, 17% for the PSV and 23% for the TAMXV when the average value from two vessels was used. The corresponding intra-CC values were 0.86, 0.83, 0.96 and 0.90, respectively. In contrast, when a lowest (PI or RI) or a highest (PSV or TAMXV) value was preferred, the CV increased to 25% for the PI, to 18% for the RI, to 28% for the PSV and to 33% for the TAMXV. Similarly, the intra-CC values decreased. All in all, the averaged PI and RI measurements in intratumoral arteries were considered to be reliable. Averaged PSV and TAMXV measurements had high CV figures, raising some doubt as to the consistency of these variables. Averaged index values were more consistent than the extreme (lowest or highest) values.

Color Doppler ultrasound measurement of beta-blocker response in normal tension glaucoma

Perfusion of the optic nerve head is a factor in the pathogenesis of glaucoma particularly in ‘normal tension glaucoma’ by whatever name. Along with intraocular pressure, vascular parameters in the watershed zone of the short posterior ciliary arteries probably determine stability or loss of nerve function as reflected in the visual field. Color Doppler ultrasound was used to measure the response of ten patients with normal tension glaucoma to topical timolol and betaxolol compared with baseline. Betaxolol lowered the index of vascular resistivity in the short posterior ciliary arteries in these patients (p<o.o5). Other comparisons were not statistically significant.

Color Doppler Ultrasound Analysis of Ocular Circulation After Topical Calcium Channel Blocker

To investigate the effect of topical administration of the calcium channel blocker verapamil on intraocular pressure and retrobulbar hemodynamics. In this randomized, prospective, double-masked study, we examined the effects of single-dose topical administration of verapamil in ten normal human volunteers by using color Doppler ultrasound imaging to measure hemodynamic parameters. Limitations of this study include single-dose application of verapamil and relatively small sample size. No systemic effect on heart rate or blood pressure was detected after administration of topical verapamil. The intraocular pressure significantly decreased compared with baseline two hours after topical 0.125% and 0.25% verapamil (P = .015 and .040, respectively). Pourcelot's ratio, an index of vascular resistance, measured in the central retinal artery was significantly reduced after topical application of 0.125% verapamil (P = .008). The change in Pourcelot's ratio primarily resulted from an increased end diastolic velocity in the central retinal artery. No significant differences compared with baseline values were detected in the color Doppler ultrasound measurements of the posterior ciliary arteries and the central retinal vein two hours after topically administered verapamil. Topical administration of verapamil decreases intraocular pressure and alters ocular hemodynamics, reducing the vascular resistance index in the central retinal artery.

Accuracy of colour Doppler ultrasound velocity measurements in small vessels

Colour Doppler ultrasound offers the possibility of imaging small vessels not visible by B-mode alone. The colour Doppler image of velocities allows the course of small vessels to be imaged in the X-Y plane of the scan provided the Doppler frequency shift is of sufficient magnitude. This permits alignments of the Doppler cursor, allowing angle correction to provide true velocity measurements from the Doppler shift obtained. Before attempting to make velocity measurements, however, it is essential to be aware of the possible error in the Z plane caused by the thickness of the Doppler sample volume. To quantify this source of error, hydrophone and flow-rig measurements were performed on an Acuson 128 colour Doppler scanner with both 5 MHz linear-array and 3.5 MHz phased-array transducers. Measurements of the transmitted pulses using a point hydrophone showed that both probes employ approximately 3.5 MHz Doppler pulses (in both colour and pulsed Doppler modes). The two transducers have the same axial resolution. In colour Doppler mode the axial length of the sample volume increases automatically with depth by up to 0.5 mm. Measurements of colour and pulsed Doppler signal strength were obtained in a controlled flow rig. Both transducers produced accurate colour flow images of the phantom at their optimum depths; flow velocity errors due to Z-plane thickness are < 5%. There was, however, substantial error outside these optimum conditions (up to 20%).

Vesicoureteric reflux in children: prediction with color Doppler imaging. Work in progress.

Unlike gray-scale sonography, color Doppler ultrasonography allows reliable visualization of the ureteric jet phenomenon. A study was undertaken to determine whether any measurable parameter predicts the presence of vesicoureteric reflux. Measurements of mean urine jet velocity, longitudinal angle, transverse angle, and distance of the origin of the jet from the midline of the bladder were obtained on 31 infants and children (62 ureters) with a proved urinary tract infection. Of these measurements, only the distance of the ureteric orifice from the midline of the bladder was found to correlate with vesicoureteric reflux (mean distance in the reflux group, 10.25 mm +/- 2.40 (standard deviation [SD]); in the nonreflux group, 7.98 mm +/- 2.40 [P = .004]). The authors conclude that the more laterally positioned the ureteric orifice, the more likely it is to reflux. Color Doppler ultrasound measurement of the laterality of the ureteric orifice may be useful for predicting which children with a urinary tract infection would benefit from voiding cystourethrography.