Spectral waveform analysis of blood flow velocity in the major arteries of six healthy, conscious immature micropigs was determined using Doppler ultrasonography. Doppler spectral tracings were recorded from the external iliac artery, femoral artery, and renal arcuate artery. Tracings were also taken from three parts of the common carotid artery and two parts of the abdominal aorta. Spectral Doppler parameters included peak systolic velocity, early diastolic velocity, peak systolic velocity-to-end diastolic velocity ratio, resistive index, and pulsatility index. In addition, the diameter of major arteries and indirect blood pressure were measured. These results from spectral Doppler analysis in major arteries may be useful as reference ranges in the future studies of vascular hemodynamics in immature micropigs.
Animals ; Arteries/physiology/*ultrasonography ; Blood Flow Velocity/physiology/*veterinary ; Male ; Swine ; Swine, Miniature ; Ultrasonography, Doppler, Color/*veterinary

Quantitative measurement of strain distribution of arterial vessel walls due to pulsatile blood flow within the vascular lumen is valuable for evaluating the elasticity of arterial wall and predicting the evolution of plaques. The present paper shows that the three-dimensional (3D) strain distribution are estimated through uni-directional coupling for 3D vessel and blood models reconstructed from intravascular ultrasound (IVUS) images with the computational. fluid dynamics (CFD) numerical simulation technique. The morphology of vessel wall and plaques as well as strain distribution can be visually displayed with pseudo-color coding.
Arteries ; diagnostic imaging ; physiology ; Elasticity ; Hemodynamics ; Humans ; Imaging, Three-Dimensional ; Pulsatile Flow ; Ultrasonography

BACKGROUNDThe offspring of women with gestational diabetes mellitus (GDM) are prone to macrosomia. However, birth weight is difficult to be correctly estimated by ultrasound because of fetal asymmetric growth characteristics. This study aimed to investigate the correlations between fetal hemodynamics, fetal growth indices in late pregnancy, and birth weight in GDM.

METHODSA total of 147 women with GDM and 124 normal controls (NC) were enrolled in this study. Fetal hemodynamic indices, including the systolic/diastolic ratio (S/D), resistance index (RI), pulsatility index (PI) of umbilical artery (UA), middle cerebral artery (MCA), and renal artery (RA), were collected. Fetal growth indices, including biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length, were also measured by ultrasound. Birth weight, newborn gender, and maternal clinical data were collected.

RESULTSThe independent samples t-test showed that BPD, HC, and AC were larger in GDM than in NC (P < 0.05). Fetal hemodynamic indices of the UA and MCA were lower (P < 0.05), but those of the RA were higher (P < 0.001) in GDM than in NC. Birth weight was higher in GDM than in NC (P < 0.001). Pearson's correlation analysis showed that hemodynamic indices of the UA were negatively correlated with birth weight, BPD, HC, and AC in both groups (P < 0.05). MCA (S/D, PI, and RI) was negatively correlated with birth weight, HC, and AC in GDM (r = -0.164, -0.206, -0.200, -0.226, -0.189, -0.179, -0.196, -0.177, and - 0.172, respectively, P< 0.05), but there were no correlations in NC (P > 0.05). RA (S/D, PI, and RI) was positively correlated with birth weight in GDM (r = 0.168, 0.207, and 0.184, respectively, P< 0.05), but there were no correlations in NC (P > 0.05).

CONCLUSIONFetal hemodynamic indices in late pregnancy might be helpful for estimating newborn birth weight in women with GDM.

Adult ; Birth Weight ; physiology ; Cerebral Arteries ; physiology ; Diabetes, Gestational ; physiopathology ; Female ; Fetal Development ; physiology ; Hemodynamics ; physiology ; Humans ; Infant, Newborn ; Male ; Pregnancy ; Pregnancy Outcome ; Renal Artery ; physiology ; Ultrasonography, Prenatal ; Umbilical Arteries ; physiology

Transcranial Doppler (TCD) was carried out to determine the resistive index (RI) values of normal canine cerebral arteries and its reproducibility and to evaluate the change of cerebral vascular resistance following diuretics administration. RI values of rostral cerebral artery (RCA) were compared between fontanelle window and temporal window. Normal ranges and reproducibility of the RI values were examined in the rostal cerebral artery (RCA) and caudal cerebral artery (CCA). And after administration of diuretics, TCD-derived RI values were measured at RCA and CCA. Cerebral vascular RI values of RCA and CCA were 0.55 +/- 0.05 and 0.55 +/- 0.03 in the normal dogs, respectively. There was no significant difference of RI between male and female; between fontanelle window and temporal window. Reproducibility of RI measurements between intraobserver and interobserver were relatively high. The RI of RCA and CCA were significantly increased 15 minutes after mannitol administration (p<0.01) and returned to baseline values by 30 minutes, but it did not significantly change after furosemide and saline administration. The results suggest that TCD is a useful test which can obtain reproducible results from any window and has the advantage of detecting subtle changes in cerebral vascular resistance.
Animals ; Cerebral Arteries/drug effects/*ultrasonography ; Diuretics/pharmacology ; Dogs/*physiology ; Feasibility Studies ; Furosemide/pharmacology ; Mannitol/pharmacology ; Reference Values ; Reproducibility of Results ; Ultrasonography, Doppler/*veterinary ; Vascular Resistance/drug effects/*physiology

Focus on the defects of the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds (such as the limited data, great amount of work and low reproducibility), we combine the earlier research results and the basic rules of the velocity spectrum image, and employing the visual basics plateau, to design and develop a software to extract the velocity signals from the spectrum image automatically. Compare the mean velocity and RNS between the PIV and the PDU resulting from the method, the correlations are r = 0.93 and r = 0.78 respectively. The study reveals the software increase the amount of valid data, decrease the amount of work and increase reproducibility of the signals extraction. The method may be an effective way to analyse the velocity spectrum image of PDU in clinic.
Arteries ; diagnostic imaging ; Blood Flow Velocity ; physiology ; Humans ; Pulsatile Flow ; Signal Processing, Computer-Assisted ; Software ; Ultrasonography, Doppler, Pulsed ; methods

In order To evaluate whether the parameters of spiral artery blood flow, as measured by transvaginal color Doppler, may be used to assess endometrium receptivity prior to embryo transfer (ET), a retrospective study of 94 infertile women who had undergone ART treatments with different outcomes (pregnant or nonpregnant) was done. Subendometrial blood flow was evaluated. The resistance index (RI), systolic/diastolic ratio (S/D) and pulsatility index (PI) were significantly lower in those who achieved pregnancy as compared with those who did not: 0.62+/-0.04 vs 0.68+/-0.04 (P<0.001), 2.66+/-0.33 vs 3.19+/-0.39 (P<0.01) and 1.15+/-0.17 vs 1.34+/-0.22 (P<0. 05), respectively. Furthermore, when RI>0. 2, PI>1. , and S/D>3. , no pregnancy occurred. These data suggest that the parameters of spiral artery blood flow could be used as a new assay in predicting endometrial receptivity before ET.
Arteries/ultrasonography ; Embryo Implantation/*physiology ; Embryo Transfer ; Endometrium/*blood supply ; Endometrium/*physiology ; Endometrium/ultrasonography ; Fertilization in Vitro ; Infertility, Female/physiopathology ; Regional Blood Flow ; Sperm Injections, Intracytoplasmic ; Treatment Outcome ; Ultrasonography, Doppler, Color

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

The changes of arterial carbon dioxide partial pressure considerably influence cerebral blood flow and different anesthetic agents have different effects on cerebrovascular physiology. However the importance of these differences in neuroanesthetic practice are unclear. Transcranial Doppler ultrasonography allows the noninvasive direct measurements of cerebral blood flow velocity and direction in the basal brain arteries. The authors performed transcranial Doppler ultrasonography to measure the blood flow velocity of middle cerebral artery in 12 patients who were anesthetized with 10 mcg/kg of fentanyl and 66 % nitrous oxide in oxygen(fentanyl group) and 12 patients with 1.0 vo1% isoflurane and 66 % nitrous oxide in oxygen(isoflurane group) during normocapnia(P(ET)CO(2)=38 mmHg) and hypocapnia(P(ET)CO(2)=28 mmHg)state. The carbon dioxide reactivity was expressed as the changes in mean blood flow velocity per unit changes in endtidal carbon dioxide partial pressure(P(ET)CO(2)). Mean blood flow velocity of middle cerebral artery decreased from 46.6+/-8.9 cm/s to 30.0+/-5.3 cm/s in the fentanyl group and 42.7+/-5.6 cm/s to 32.5+/-4.6 cm/s in the isoflurane group as the P(ET)CO(2) decreased from 38 mmHg to 28 mmHg. There was a significant difference between the CO2 reactivity of fentanyl group(1.7+/-0.7 cm/s/mmHg) and isoflurane group(1,0+/-0,2 cm/s/mmHg) (p<0.05). It is concluded that hyperventilation is more likely to affect cerebral blood flow during fentanyl-nitrous oxide anesthesia than during isoflurane-nitrous oxide anesthesia.
Anesthesia ; Anesthetics ; Arteries ; Blood Flow Velocity ; Brain ; Carbon Dioxide ; Fentanyl* ; Humans ; Hyperventilation ; Isoflurane* ; Middle Cerebral Artery ; Nitrous Oxide ; Partial Pressure ; Physiology ; Ultrasonography, Doppler, Transcranial

The severity of carotid intima-media thickness (IMT) is an independent predictor of atherosclerosis which causes transient cerebral ischemia, stroke, and coronary events such as myocardial infarction. The IMT consists of intima thickness (IT) and media thickness (MT). However, the Individual clinical significance of IT and MT has not been well studied. We devised a method of measuring IT, MT, and IMT using B-mode ultrasound image processing technique for the diagnosis of atherosclerosis. To inspect the clinical significance of IT, MT, and IMT, one hundred forty-four consecutive patients (mean age; 57 years old, 72 males) were underwent common carotid artery scanning using high-resolution ultrasound. Results showed that, the IT (p<0.05), MT (p<0.05) as well as IMT (p<0.01) of patients with atherosclerotic disease were significantly thicker than that of the patients without atherosclerotic disease. Patients with hypertension showed significantly thicker IT (p<0.01), MT (p<0.001), and IMT (p<0.001). However, only IT was thicker in patients with smoking (p<0.01). The IT (r=0.374, p=0.001), MT (r=0.433, p=0.000), and IMT (r=0.479, p=0.000) showed positive correlation with age. The coefficients of determination (r(2)) were estimated to be 92.4% for IMT and MT, 49.1% for IMT and IT, and 27.4% for IT and MT. This result suggests that the intima layer of the carotid artery has a different physiology with the media layer.
Atherosclerosis ; Carotid Arteries ; Carotid Artery, Common ; Carotid Intima-Media Thickness ; Diagnosis ; Humans ; Hypertension ; Ischemic Attack, Transient ; Middle Aged ; Myocardial Infarction ; Physiology ; Smoke ; Smoking ; Stroke ; Ultrasonography