Resistivity Index Research Articles

Doppler ocular ultrasound in patients with type 2 diabetes mellitus

Purpose: To determine ocular blood flow parameters by Doppler ultrasound scanning in type 2 diabetic patients with different stages of diabetic retinopathy. Material and Methods: In this prospective study, forty-five patients (90 eyes) with type 2 diabetes mellitus were divided into three groups of 15 patients each: no diabetic retinopathy group (DR0), non-proliferative retinopathy (NPDR), and proliferative retinopathy (PDR) groups. Doppler indices such as systolic blood flow velocity (Vs), diastolic blood flow velocity (Vd), time-averaged maximum velocity (TAMXV), pulsatility index (PI) and resistivity index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were determined. ANOVA was used for quantitative comparisons between the three groups. Results: There was a significant (р less 0.05) decrease in (a) the Vs from 71.1 +- 20.6 cm/s in the DR0 group to 59.9 +- 16.7 cm/s in the NPDR group and 47.4 +- 16.4 cm/s in the PDR group, (b) Vd from 22.1 +- 6.9 cm/s to 17.0 +- 6.6 cm/s and 12.3 +- 5.9 cm/s, respectively; and (c) TAMXV from 37.2 +- 11.3 cm/s to 31.9 +- 9.1 cm/s and 25.3 +- 9.7 cm/s, respectively, and an increase in the RI from 0.69 +- 0.06 cm/s to 0.71 +- 0.09 cm/s and 0.75 +- 0.08 cm/s, respectively, in the OA. In addition, there was a significant decrease in the Vd from 9.9 +- 5.4 cm/s in the DR0 group to 8.1 +- 3.8 cm/s in the NPDR group and 5.5 +- 3.1 cm/s in the PDR group, and an increase in the PI from 1.34 +- 0.16 cm/s to 1.46 +- 0.28 cm/s and 1.54 +- 0.24 cm/s, respectively, and in the RI from 0.71 +- 0.06 cm/s to 0.75 +- 0.07 cm/s and 0.80 +- 0.05 cm/s, respectively, in the CRA. Moreover, there was a significant decrease in the Vd from 4.3 +- 1.6 cm/s in the DR0 group to 3.2 +- 2.0 cm/s in the NPDR group and 3.1 +- 2.2 cm/s in the PDR group, and an increase in the PI from 1.32 +- 0.21 cm/s to 1.37 +- 0.24 cm/s and 1.54 +- 0.26 cm/s, respectively, and in the RI from 0.76 +- 0.04 cm/s to 0.82 +- 0.06 cm/s and 0.82 +- 0.06 cm/s, respectively, in the SPCA. Conclusion: We found that the arteries examined in patients with diabetic retinopathy tended to have decreased blood flow velocities and increased resistivity and pulsatility indices, with the greatest changes observed in patients with PDR. In addition, the difference in mean values of most Doppler indices between the PDR and NPDR groups was larger than that between the NPDR and DR0 groups.

Pore-scale analysis of hydrate saturation on the physical parameters of hydrate-bearing sediment with different particle shapes

Methane hydrate is the most potential novel energy source with huge reserves to be developed, and is the priority of countries' future energy development strategies. Evaluating the basic physical characteristics of hydrate reservoirs, especially permeability, thermal, and electrical conductivity, is essential for clarifying the main controlling factors of physical characteristics and formulating a reasonable development strategy. Accordingly, 16 cementing hydrate-bearing models with different particle shapes were constructed account of a new three dimensions morphologic modeling algorithm for hydrate in this study. Based on the above models, the evolution of pore space distribution and basic physical properties of hydrate-bearing sediments (HBS) have been analyzed via pore network modeling (PNM) and finite volume method (FVM). The results show that (1) the quantity of pores and throats of HBS with round particles is higher, and the average radius is smaller than those of HBS with irregular particles, (2) increasing hydrate saturation leads to a decrease in absolute permeability, with a more rapid decrease in permeability for HBS with irregular particles, (3) the thermal conductivity of HBS with round particles exceeds those of HBS with irregular particles, and the their curves remain parallel with increasing hydrate saturation, (4) the resistivity index of HBS with round particles increases faster as hydrate forms, and the conductivity is always smaller than those of HBS with irregular particles.

Experimental measurements and response analysis of resistivity of reservoirs with complex wettability: A case study of Yan’an Formation, Ordos Basin, China

Resistivity logs are commonly used to distinguish oil and water reservoirs. However, the complex hydrocarbon accumulation pattern in the study area leads to complex wettability, which significantly affects the resistivity as well as the density and neutron logs and causes difficulties in fluid-type identification. To understand the resistivity characteristics and accurately identify the fluid types, resistivity experiments of core samples selected by the density and neutron logs are performed. The nuclear magnetic resonance (NMR) is simultaneously measured to determine the rock wettability. Instead of the conventional “aged” method for restoring the original wettability, a new set of experimental procedures is developed for obtaining resistivity and NMR [Formula: see text] spectra of samples with wettability as close as possible to that of the original reservoir. Specifically, samples with and without oil washing are measured separately, and a simple correction method for the resistivity index is developed. Moreover, the difference in the water salinity of different wells is considered. The results find that the resistivity index of samples drilled from possible oil-wet reservoirs indicated by the “abnormal” density and neutron responses varied from 2.807 to 5.388, whereas that of possible water-wet reservoirs was less than 2.0. The [Formula: see text] spectra at different states confirm the wettability of the samples. The resistivity index versus saturation ([Formula: see text]–[Formula: see text]) curves of oil-wet rocks are nearly straight lines other than the theoretical concave lines in double-logarithmic coordinates. Oil washing changes the rock wettability to varying degrees. Furthermore, the resistivity log responses of the reservoirs are accurately interpreted using the experimental data. The resistivity is simultaneously affected by the salinity, wettability, and saturation. Finally, based on the factors affecting the reservoir resistivity, fluid identification plots are established for reservoirs with different wettabilities. The agreement rates of identification using the crossplots and oil test are greater than 90%.

Wireless Acquisition for Resistivity Index in Centrifuge – WiRI: A Comparative Study of Three Pc-RI Methods

Technological improvements and innovations are made to offer solutions with superior efficiency in terms of cost, quality, speed, or all of them. In the special core analysis (SCAL) field, the conventional resistivity index measurement (the porous plate technique) is a cost-effective method that provides good-quality results but is very time consuming. For this purpose, several methods were developed to reduce the time taken to acquire resistivity measurements. In 2017, we proposed the ultra-fast capillary pressure and resistivity index measurements (UFPCRI) combining centrifugation, nuclear magnetic resonance (NMR) imaging, and resistivity profiling. Since 2021, the wireless resistivity index (WiRI) method allows the acquisition of capillary pressure and resistivity index in a matter of days. This method is based on a new in-house system to acquire wirelessly resistivity indexes along a rock sample during centrifugation. The determination of the resistivity vs. saturation curve and the n exponent of Archie’s law is done thanks to an optimization algorithm. In this paper, we present the results obtained from multiple simulations and experiments for WiRI, UFPCRI, and porous plate to discuss the advantages and drawbacks of each method in terms of reliability and experimental duration. Six rock samples are studied. A comparison of the three methods regarding Archie’s n exponent, resistivity indexes, and capillary pressure curves is performed.

Analytical Models for Predicting the Formation Resistivity Factor and Resistivity Index at Overburden Conditions

In this study, new parameters referred to as rock resistivity modulus (RRM) and true resistivity modulus (TRM) were defined. Analytical models were developed based on RRM, TRM, and Archie’s equation for predicting formation resistivity factor (FRF) and resistivity index (RI) under overburden pressure conditions. The results indicated that overburden FRF is dependent on FRF at initial pressure (ambient FRF), RRM, and net confining pressure difference. RRM decreases with cementation factor and rock compressibility. The proposed FRF model was validated using 374 actual core data of 79 plug samples (31 sandstone and 48 carbonate plug samples) from three sandstone reservoirs and four carbonate reservoirs, measured under four to six different overburden pressures. The developed FRF model fitted the experimental data with an average relative error of 2% and 3% for sandstone and carbonate samples, respectively. Moreover, the applications and limitations of the models have been investigated and discussed. Further theoretical analysis showed that overburden RI is a function of RI at initial pressure, TRM, and net confining pressure difference. The developed models supplement resistivity measurements and can be applied to estimate FRF, RI, and saturation exponent (n) variations with overburden pressure.

Use of Doppler indices of vascular impedance for diagnosing testicular degeneration in stallions

Spectral Doppler ultrasonography is used to evaluate testicular blood flow in males. Further, the correlation between testicular function and values of Doppler indices, Resistive Index (RI), and Pulsatility Index (PI) were reported in men and several animal species (Velasco and Ruiz. Animals 2020;11:1-13). We have previously shown that stallions with oligospermia associated with medically induced testicular degeneration (TD) have higher values of Doppler indices of testicular blood flow than normal stallions (Pozor et al. JEVS 2014;34:38-9). The goal of this retrospective study was to validate Doppler indices of vascular impedance for the identification of stallions with TD. Medical records from five adult stallions with clinical signs of testicular degeneration (small, flaccid, hypoechoic testes; oligospermia or azoospermia, necrospermia; immature germ cells, detached sperm heads) were reviewed. Three of the five subfertile stallions were later castrated, and severe TD was confirmed histologically. Spectral Doppler ultrasound examination of the marginal aspect of the testicular artery was performed by the same operator, and values of RI and PI were determined for each testis. Doppler indices in the five subfertile stallions were compared with those of five normal fertile stallions, evaluated four times in different seasons, using Kruskal-Wallis One-Way ANOVA method. There were no significant differences betweensubfertile and normal stallions for RI (Mean: 0.66 vs. 0.63, SD: 0.08 vs. 0.11, respectively; P>0.5) or PI (Mean: 1.18 vs. 1.22, SD: 0.23 vs. 0.40, respectively; P>0.5). In addition, information from a pony stallion was obtained over four consecutive years. An initial testicular blood flow evaluation was performed on this stallion at 18 yrs. of age, when good fertility and normal semen parameters were confirmed. Over the four years, the pony stallion's testicular volume decreased from 95 cm3 to 41 cm3. The stallion's total sperm numbers fell from an average of 4.6 billion in Year 1 to 0 in Year 4, indicating progressive TD, which was later confirmed histologically. Values of Doppler indices of vascular impedance in the affected stallion were compared to a pony stallion of a similar size and age with normal testicular and seminal parameters. Doppler indices in the affected stallion did not change significantly over the 4 years evaluated (RI: 0.58 – 0.65; PI: 1.02 – 1.12). Further, the Doppler indices in the affected stallion were not different from the normal pony stallion. Based on data collected from this small population of stallions, Doppler indices of testicular blood flow may not be reliable for diagnosing testicular degeneration in stallions. We have no clear explanation for why the results presented here differ from our previous study. Perhaps different etiologies of TD, acute induced vs chronic progressive, contributed to this difference.

Impact of ovulation inducers on ovarian artery in mares: pulsatility and resistivity indexes

A failure of vascular development in reproductive organs may be the cause of several dysfunctions during the estrous cycle and gestation. Therefore, it is important to evaluate the in vivo influences of ovarian vaso- irrigation on ovulation. The ovarian follicles need an adequate blood supply for oxygen, nutrients, and hormones, besides eliminating CO2 and other metabolites (Bruno et al. Animal Reproduction. 2009; 6, 2:371-379). Transrectal ultrasonography (US) with color, power, and spectral Doppler US has been used to study blood flow and ovarian perfusion in mares (Acosta et al. Biology of Reproduction. 2004b; 71, 2: 502-507). Studies have shown a daily increase in vascularization of the wall of the dominant follicle as it approaches the day of ovulation (Gastal et al. Animal Reproduction Science. 2007; 102, 3-4: 314-321); However, a few hours before ovulation, an abrupt decrease in blood perfusion of the follicular wall has been detected (Ginther et al. Journal of Equine Veterinary Science. 2007a; 27, 1: 20-27). The drugs most used as ovulation inducers in horses are human chorionic gonadotropin (hCG) and analogues of gonadotropin-releasing hormone (GnRH), such as deslorelin (Chavatte & Palmer Equine Veterinary Education. 1998; 10, 26-30). Using different ovulation inducers, this study aimed to evaluate changes in ovarian arteryblood flow after induction of ovulation in mares with follicles ≥ 35mm diameter. Twenty-eight estrous cycles were followed, randomly and equally distributed: GI: control mares without treatment; GII: 1000 IU IV of hCG; GIII: 750µl IV of deslorelin; GIV: 250µg IM of hysterelin. The ovarian artery pulsatility and resistivity indexes (PI and RI) were measured. Thereafter, estrous cycles were followed every 12 hours from time 0 (induction) until ovulation using B-mode US and spectral mode Doppler US of ovarian arteries. Statistical analysis was performed with ANOVA, a p-value of <0.05 was considered significant. No statistical difference was found in PI between groups (p=0.1297) of at the different evaluation times. When the times of analysis were compared separately between the groups, no statistical difference was found between 0h (p= 0.7092), 12h (p= 0.5148), 24h (p=0.2642), and 36h (p=0.582). Similarly, the RI did not differ between the groups analyzed (p= 0.1397), regardless of the time of evaluation, nor between the timepoints analyzed separately between 0h (p= 0.5049), 12h (p= 0.7334), 24h (p=0.3589) and 36h (p=0.1621). It can be concluded that although an increase in vascularization of the wall of the dominant follicle occurred, the PI and RI of the ovarian artery were not influenced by any ovulation inducer of the pre-ovulatory follicles.

Role of Multiparametric Ultrasound in Evaluating Hepatic Acute Graft-versus-Host Disease: An Animal Study.

Hepatic acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is one of the leading causes of early non-recurrent death. The current diagnosis is based mainly based on clinical diagnosis, and there is a lack of non-invasive quantitative diagnosis methods. We propose a multiparametric ultrasound (MPUS) imaging method and explore its effectiveness in evaluating hepatic aGVHD. In this study, 48 female Wistar rats were used as receptors and 12 male Fischer 344 rats were used as donors for allo-HSCT to establish aGVHD models. After transplantation, 8 rats were randomly selected for ultrasonic examination weekly, including color Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and shear wave dispersion (SWD) imaging. The values of nine ultrasonic parameters were obtained. Hepatic aGVHD was subsequently diagnosed by histopathological analysis. A classification model for predicting hepatic aGVHD was established using principal component analysis and support vector machines. According to the pathological results, the transplanted rats were categorized into the hepatic aGVHD and non-GVHD (nGVHD) groups. All parameters obtained by MPUS differed statistically between the two groups. The first three contributing percentages of principal component analysis results were resistivity index, peak intensity and shear wave dispersion slope, respectively. The accuracy of classifying aGVHD and nGVHD using support vector machines reached 100%. The accuracy of the multiparameter classifier was significantly higher than that of the single parameter. The MPUS imaging method has proven to be useful in detecting hepatic aGVHD.

Doppler Evaluation of Uterine Arteries in Different Phases of Menstrual Cycle in Young Adult Females with Regular Cycles

Background: The menstrual cycle is nature's cyclical method of getting ready for pregnancy. The uterine lining grows each month in preparation for implantation by a fertilized ovum. Cyclic endometrium may be non-invasively assessed with Doppler sonography and leads to alterations in local vascular patterns. The pulsatility index (PI), which measures the uterine artery (UtA) impedance, displays a predictable pattern during the typical menstrual cycle. Aim: To evaluate the flow of blood through the uterine arteries in young adult women with regular cycles during various menstrual cycle stages. Place of study and duration of study: Department of Radiology, University Ultrasonography Clinic in Green Town, Lahore. Between January 2022 and October 2022. Methodology: A comparative study was carried out at the University Ultrasonography Clinic in Green Town, Lahore, Pakistan. In this study, 180 patients between the ages of 16 and 35 were enrolled using a convenient sampling technique.All the married, and unmarried ages between 13- and 40 years old having regular periods once a month were involved in this study. Results: 180 patients in all were involved in this study comprising 60 females of each phase of the menstrual phase, 23 patients age were 25 age, 19 patients were 23 age, 20 patients were 18 age, 15 patients were 22, and 9 patients were the age of 29,30,31 years. RI of the right ovary was 0.5938 ± 0.8, the mean RI of the left ovary was 6.5083 ± 0.92357 forthe 10-20 days phase cycle, RI of the right ovary was 0.5937 ± .05266, the mean RI of the left ovary was 10.6967 ± 1.13466 of 11-20 days phase cycle, RI of right ovary was 0.5925 ± .05423, mean RI of left ovary was 6.7083±1.10258 of 21-30 days phase cycle.The uterine artery's resistivity index is compared in three menstrual cycle phases which are days 1 to 10, 11 to 20, and 21 to 30. No statistical difference was found in the right three means of the uterine artery's resistivity index as P-value=0.989 &gt; ∞=0.05. The averages of the Resistivity index of the uterine artery(left)in the three phases of the menstrual cycle are proved to be equal as we failed to find statistically significant differences where P-value=0.975 &gt; ∞=0.050. Conclusion: In this study, we have concluded that endometrial thickness and uterine artery resistivity index, determined ultrasonographically depend upon the phase of the menstrual cycle. The endometrialthickness progressively increases throughout the menstrual phase with no change in the resistive index of both uterine arteries. Keywords: Doppler ultrasound, uterine arteries, resistive index, pulsative index, endometrium stripe thickness.

(359) Validation of Peripheral Endothelial Assessment and Central Arterial Tonometry as Tools in Arteriogenic Erectile Dysfunction and Can These Tools Aid in Better Selection of Patients for LI-ESWT Treatment Improving Success Rates?

Abstract Introduction An important mechanism of ED is vascular endothelial function injury or disorder and low-intensity extracorporeal shock wave therapy (LI-ESWT) can stimulate and promote vascular regeneration, especially in failed PDE5i. The present selection criteria used for EDSWT are subjective in the form of IIEF, EHS or SEP with no objective definition of the extent of vascular involvement. There is a need to comprehensively evaluate ED including the extent of local and systemic involvement. Objective To develop objective parameters of validated assessment of endothelium in men with organic erectile dysfunction and to evaluate if they could be used to plan accurate PDE5i, non-invasive modalities of treatment. Methods In a prospective study, patients who were earlier evaluated and had vasculogenic ED and failed PDE5i treatment were clinically re-evaluated with questionnaires and CDDU. Additionally endothelial function and large arterial stiffness was assessed with the Vendys (reactive hyperaemia) &amp; Sphygmocor (central arterial pressure waveform analysis). Categories identified were, endothelial dysfunction by Vendys, Aortic augmentation index abnormality by Sphygmocor (age corrected), combined abnormality with poor scores with or without metabolic comorbidity. All three groups underwent LI-ESWT with low dose PDE5 inhibitors with a revised protocol. Results Validation of diagnostic tools was done in thirty five patients aged 48.24 ± 4.6 years (mean ± SD) with a mean IIEF score of 8.4 were evaluated by the three techniques. Positive predictive value (PPV) of the three techniques was similar, in the range 89-91% and a negative predictive value (NPV) around 41-45%. CDDU had highest sensitivity at 85%, but low specificity of 55%, followed by Sphygmocor® at 77% and Vendys at 75% and the latter techniques had better specificity of 70%. Parameter Penile Doppler SphygmoCor® Vendys® Value 95% CI Value 95% CI Value 95% CI Sensitivity 85 % 70.1-94.3 77.5 % 61.5-89.1 75 % 58.8-87.3 Specificity 55.6 % 21.2-86.3 70.0 % 34.7-93.3 70 % 34.7-93.3 Positive likelihood Ratio 1.91 0.91-4.02 2.58 0.99-6.76 2.50 0.95-6.55 Negative likelihood Ratio 0.27 0.11-0.69 0.32 0.16-0.65 0.36 0.18-0.70 PSV (N) IIEF Class (N) % &amp;lt; 25 (22) Severe (18) 81.82 44.00 Mod (3) 13.64 Mild (1) 4.55 25-30 (17) Severe (0) 0.00 34.00 Mod (14) 82.35 Mild (3) 17.65 CDDU Vs IIEF score The patients were grouped into three arms Vendys abnormality, Sphygmocor and combined; for Li-ESWT treatment (15 each). Pre and Post questionnaire based assessment was done and maximum improvement of IIEF was in the Alx abnormality arm with poor results in combined abnormality. Conclusions The aortic strain index and distensibility index were impaired in patients with ED. Vendys® SphygmoCor® are new tools in diagnosis of ED and superior to penile Doppler or questionnaire assessment. Li-ESWT is most beneficial in patients with Aortic elastic abnormality probably due shock wave effect on sheer stress of vessels by altering vessel wall pulsatality and resistivity index. Disclosure No

Effect of terlipressin on systemic and hepatic hemodynamics in patients undergoing liver transplantation

ABSTRACT Background and Aims Liver transplantation is associated with hemodynamic instability. Systemic and Splanchnic circulations interact closely. Portal hypertension is linked to vasodilatory molecules resulting in arterial vasodilatation. Terlipressin, is a synthetic vasopressin analogue causes selective vasoconstriction of splanchnic arteriols, thus decreasing splanchnic blood flow and shifting blood from the splanchnic to the systemic circulation resulting in enhanced systemic hemodynamics. This study aimed to assess the impact of intraoperative terlipressin on systemic and hepatic hemodynamics in recipients of living donor liver transplantation (LDLT). Methods The present longitudinal observational study was carried out at Ain Shams Center for Organ Transplant on 30 cases suffering from portal hypertension and chronic liver disease undergoing LDLT. Subjects were equally categorized into two groups: Group 1(control): patients did not receive intraoperative terlipressin, Group 2 (terlipressin): patients received terlipressin (1 mg intravenously over 10 min) just after exposure of the portal vein to maintain mean arterial blood pressure over 65 mmHg. Results Systolic and diastolic blood pressure were better preserved in the terlipressin group, with reduced norepinephrine requirements as well as a substantial decline in the heart rate during the anhepatic and reperfusion phases (P < 0.05). Terlipressin significantly decreases portal venous pressure with (P = 0.03) and portal vein flow (P < 0.001) without altering the hepatic artery resistivity index (HARI) (P = 0.219). Conclusion Intraoperative terlipressin during liver transplantation surgery was associated with improved systemic hemodynamics despite decreased portal venous pressure and blood flow, without affecting HARI.

Novel superpixel method to visualize fundus blood flow resistivity in healthy adults

We aimed to perform superpixel segmentation of ocular blood flow maps obtained using laser speckle flowgraphy (LSFG) and investigate the effects of systemic parameters such as body weight, height, and sex on ocular blood flow resistivity. We studied 757 healthy participants (583 men, 174 women). We calculated the average beat strength over mean blur rate (BOM) as a LSFG resistivity index, as a function of age and sex using ordinary regions of interest (ROI) centered on the optic nerve head (ONH), the retinal vessels region and tissue around the ONH, and the choroid (CHD). We compared the ROI and superpixel-based methods, which are segmented based on image processing, for calculating the BOM. The sex differences in the BOM for the ONH, retinal-vessels region and tissue region of the ONH and CHD were significant for individuals aged ≤ 50 years (P < 0.01) but not those > 50 years old (P > 0.05). The average BOMs calculated using the ROI and superpixel methods were strongly correlated in the ONH (coefficient = 0.87, R2 = 0.8, P < 0.0001, n = 5465). In summary, a superpixel-segmented BOM map is suitable for two-dimensional visualization of ocular blood flow resistivity.

DOPPLER INDICES OF FETAL MIDDLE-CEREBRAL AND UMBILICAL ARTERIES IN NORMAL 28–40 WEEKS PREGNANCIES

Objectives: The aim of the study was to establish normative data for the pulsatility index (PI), resistive index, and cerebro placental ratio of umbilical artery (UA), and fetal middle cerebral artery (MCA) of Indian pregnant women in the third trimester of pregnancy using multiples of the median and percentile reference range. Methods: It was a cross-sectional study; the study was carried out at the Department of Obstetrics and Gynaecology and Radiology in MGM Medical College and LSK Hospital, the tertiary care and teaching hospital. A total of 200 cases were enrolled for this study. Patients with Singleton low-risk pregnancies with confirmed gestational age, normal anatomy, normal estimated fetal weight, and born at term with birth weight between 10th and 90th percentile and gestational age was based on LMP date, corrected if required by trimester first/second (Before 20 weeks) fetal sonographic parameters were included in the study. Results: We found from 28 weeks to 39 weeks of gestational age, MCA PI showed a significantly positive correlation with the cerebro-placental ratio (CPR) 40th week of gestational age. We found no significant correlation. While from 28 weeks to 40 weeks of gestational age, UA PI showed a significantly negative correlation with the CPR. Conclusion: Doppler ultrasound is used as a part of the clinical protocol in the surveillance of pregnancies. The UA and MCA Doppler indices and CPR are currently used to modify the scheduling of antepartum surveillance and, in some cases, to timely delivery of the compromised fetus. Researchers measured the pulsatility, resistivity, and cardiac indices of the UA and the fetal MCA between 28 and 40 weeks of gestation to establish a normal range.

Climatic seasons and time of the day influence thermoregulation and testicular hemodynamics in Santa Inês rams raised under humid tropical conditions

This study evaluated the possible association between the diurnal variations of climatic factors during the rainy (RS) or less rainy (LS) seasons on the testicular hemodynamics and thermoregulatory responses of hair sheep rams raised in a humid tropical climate. Santa Inês rams (n = 6) underwent evaluation of general and testicular physiological parameters (heart and respiratory rates, internal and scrotal temperatures, internal-scrotal temperature gradient, scrotal distention, and color Doppler ultrasound evaluation of the spermatic cords and spectral analyses of testicular arteries) over six consecutive weeks per season at three separate times daily (morning = 8:00 a.m., noon = 12:00 p.m., and afternoon = 5:00 p.m.) during the RS and LS. Climatic air temperature and relative humidity data were recorded, and the temperature and humidity index (THI) was calculated. Higher thermal challenge was observed in LS relative to RS (air temperature = 28.0 vs. 30.9 °C; relative humidity = 84.1 vs. 69.9%; THI = 80.0 vs. 82.5; P < 0.05). In both seasons, respiratory rate and internal temperature were normal, demonstrating the animals’ adaptability. In RS, however, a higher scrotal temperature was recorded in relation to LS (35.0 vs. 34.7 °C; P < 0.05), with a gradual increase from morning to afternoon. Lower resistivity (0.40 vs. 0.64; P < 0.05) and pulsatility (0.55 vs. 1.14; P < 0.05) indices, and a higher rate of high-velocity blood flow of testicular arteries (71.1 vs. 60.6%; P < 0.05) were observed in RS compared to LS. The lowest correlations between testicular hemodynamic, physiological variables, and environmental parameters (P < 0.05) were observed in the morning. In conclusion, testicular thermoregulation and testicular hemodynamics were influenced by the climatic seasons and time of the day, being more efficient in the LS season and with less interference from environmental factors in the morning.

Evaluation of cerebral hemodynamic alterations by transcranial Doppler in neonatal sepsis

Background Transcranial Doppler is a noninvasive approach with high temporal resolution, permitting continuous cerebral blood flow velocity recording through major cerebral arteries. Aim To determine cerebral blood flow (CBF) changes in neonatal sepsis (NS) by ultrasound (US) Doppler examination. Patients and methods This prospective case–control trial was conducted on 60 neonates who were divided into two groups: group I (sepsis): 32 neonates with NS diagnosed by clinical and laboratory data and group II (control): 28 healthy neonates with gestational age and sex matched. All cases underwent detailed antenatal and natal history, clinical and laboratory investigations and transcranial Doppler examination with assessment of CBF. Results As regards anterior cerebral artery (ACA) and middle cerebral artery (MCA), peak systolic velocity (PSV) (cm/s) and end-diastolic velocity (EDV) (cm/s) were significantly increased in the sepsis group than in the control group (P&lt;0.001), but both resistive index and pulsatility index were significantly decreased, in the sepsis group than in the control group (P&lt;0.001). Validity of MCA PSV with a cut-off point of 55.4 detects a sensitivity of 94% and specificity of 86%; validity of MCA EDV with a cutoff point of 18 detects a sensitivity of 94% and specificity of 89%; validity of ACA PSV with a cutoff point of 49.3 detects a sensitivity of 88% and specificity of 93%; validity of ACA EDV with a cutoff point of 21 detects a sensitivity of 91% and specificity of 93%. Conclusion NS was found to elevate both PSV, EDV, decrease resistivity, and pulsatility indices causing an elevated CBF and a decreased resistance.

A Scoping Review of Cerebral Doppler Arterial Waveforms in Infants.

Cerebral Doppler ultrasound has been an important tool in pediatric diagnostics and prognostics for decades. Although the Doppler spectrum can provide detailed information on cerebral perfusion, the measured spectrum is often reduced to simple numerical parameters. To help pediatric clinicians recognize the visual characteristics of disease-associated Doppler spectra and identify possible areas for future research, a scoping review of primary studies on cerebral Doppler arterial waveforms in infants was performed. A systematic search in three online bibliographic databases yielded 4898 unique records. Among these, 179 studies included cerebral Doppler spectra for at least five infants below 1 y of age. The studies describe variations in the cerebral waveforms related to physiological changes (43%), pathology (62%) and medical interventions (40%). Characteristics were typically reported as resistance index (64%), peak systolic velocity (43%) or end-diastolic velocity (39%). Most studies focused on the anterior (59%) and middle (42%) cerebral arteries. Our review highlights the need for a more standardized terminology to describe cerebral velocity waveforms and for precise definitions of Doppler parameters. We provide a list of reporting variables that may facilitate unambiguous reports. Future studies may gain from combining multiple Doppler parameters to use more of the information encoded in the Doppler spectrum, investigating the full spectrum itself and using the possibilities for long-term monitoring with Doppler ultrasound.

Preliminary study on the application of bioimpedance analysis to measure the psoas major muscle in older adults.

For the assessment of sarcopenia or other geriatric frailty syndromes, psoas major area may be one of the primary indicators. Aim to develop and cross-validate the psoas cross-sectional area estimation equation of L3-L4 of the elderly over 60 years old by bioelectrical impedance analysis (BIA). Ninety-two older adults with normal mobility were enrolled (47 females, 45 males), and were randomly divided into a modeling group (MG, n = 62) and validation group (VG, n = 30). Computed tomography (CT) was used to measure the psoas major area at the' L3-L4 lumbar vertebrae height as a predictor. Estimated variables were height (h), whole body impedance (Zwhole), whole body impedance index (h2/Zwhole, WBI), age, gender (female = 0, male = 1), and body weight (weight) by standing BIA. Relevant variables were estimated using stepwise regression analysis. Model performance was confirmed by cross-validation. BIA estimation equation for PMM obtained from the MG was: (PMMBIA = 0.183 h2/Z- 0.223 age + 4.443 gender + 5.727, r2 = 0.702, n = 62, SEE = 2.432 cm2, p < 0.001). The correlation coefficient r obtained by incorporating the VG data into the PMM equation was 0.846, and the LOA ranged from -4.55 to 4.75 cm2. PMMBIA and PMMCT both correlate highly with MG or VG with small LOA. The fast and convenient standing BIA for measuring PMM may be a promising method that is worth developing.

Intrarenal Doppler ultrasonography in patients with HFrEF and acute decompensated heart failure undergoing recompensation

ObjectivesRenal venous congestion due to backward heart failure leads to disturbance of renal function in acute decompensated heart failure (ADHF). Whether decongestion strategies have an impact on renal venous congestion is unknown. Objective was to evaluate changes in intrarenal hemodynamics using intrarenal Doppler ultrasonography (IRD) in patients with heart failure with reduced ejection fraction (HFrEF) and ADHF undergoing recompensation.MethodsProspective observational study in patients with left ventricular ejection fraction (LV-EF) ≤ 35% hospitalized due to ADHF. IRD measurement was performed within the first 48 h of hospitalisation and before discharge. Decongestion strategies were based on clinical judgement according to heart failure guidelines. IRD was used to assess intrarenal venous flow (IRVF) pattern, venous impedance index (VII) and resistance index (RI). Laboratory analyses included plasma creatinine, eGFR and albuminuria.ResultsA number of 35 patients with ADHF and LV-EF ≤ 35% were included into the study. IRD could be performed in 30 patients at inclusion and discharge. At discharge, there was a significant reduction of VII from a median of 1.0 (0.86–1.0) to 0.59 (0.26–1.0) (p < 0.01) as well as improvement of IRVF pattern categories (p < 0.05) compared to inclusion. Albuminuria was significantly reduced from a median of 78 mg/g creatinine (39–238) to 29 mg/g creatinine (16–127) (p = 0.02) and proportion of patients with normoalbuminuria increased (p = 0.01). Plasma creatinine and RI remained unchanged (p = 0.73; p = 0.43).DiscussionThis is the first study showing an effect of standard ADHF therapy on parameters of renal venous congestion in patients with HFrEF and ADHF. Doppler sonographic evaluation of renal venous congestion might provide additional information to guide decongestion strategies in patients with ADHF.Graphical abstract

Resistivity index mapping in Kidney based on ultrasensitive Pulsed-Wave Doppler and automatic spectrogram envelope detection.

In recent years, ultrasensitive Pulsed-Wave Doppler (uPWD) ultrasound (US) has emerged as an alternative imaging approach for microcirculation imaging and as a complementary tool to other imaging modalities, such as positron emission tomography (PET). uPWD is based on the acquisition of a large set of highly spatiotemporally coherent frames, which allows high-quality images of a wide field of view to be obtained. In addition, these acquired frames allow calculation of the resistivity index (RI) of the pulsatile flow detected over the entire field of view, which is of great interest to clinicians, for example, in monitoring the transplanted kidney course. This work aims to develop and evaluate a method to automatically obtain an RI map of the kidney based on the uPWD approach. The effect of time gain compensation (TGC) on the visualization of vascularization and aliasing on the blood flow frequency response, was also assessed. A pilot study conducted in patients referred for renal transplant Doppler examination showed that the proposed method provided relative errors of about 15% for RI measurements with respect to conventional pulsed-wave (PW) Doppler.

Frequency of Diabetic Nephropathy, through Renal Resistive Index, among Type 2 Diabetic patients with Normal Albuminuria.

Background: The diabetes mellitus is an old known disease and closely related to the renal impairment as a cause. The exact duration for any damage to renal functions is not known but early detection of any such happening is a requirement. Many measures explain the renal damage, proteinuria is one among them. Still it appears after some damage is done. Aim: To measure the RRI for renal arteries and find frequency of diabetic nephropathy among type II diabetic patients with normal albuminuria. Methods: It was a cross-sectional study performed at Shaikh Zayed hospital Lahore, in collaboration of Diabetes Clinic and Radiology Department during January 2020 to January 2021. Here 300 diabetic patients of type 2, with normal albumin creatinine ratio were selected. Both genders with age above 18 years with albuminuria below 30 mg/g and no known diabetic nephropathy were included. Pregnant women, patients with GFR &lt;60ml/min/1.73m2 and those having any history of renal stones and known CKD patients were excluded. Results: One hundred and seventy seven (59.0%) were males, only 38(12.7%) were above 60 years age, 37(12.3%) were obese and 180(60.0%) had duration of diabetes ≤5 years. There were 60(20.0%) smokers, 106(35.3%) had hypertension and 5.0% had fatty liver of grade III. On ultrasound 75(25.0%) cases had both kidneys with irregular contour while 44(14.7%) had raised Parenchymal &amp; sinus echoes in both kidneys. On RRI, 23.3% of the cases were diagnosed to have diabetic nephropathy with max(RRI) &gt;0.70. Conclusion: Renal resistive indexcan diagnose diabetic nephropathy at early stage. Keywords: Diabetic nephropathy, Renal resistivity index, Type II diabetes mellitus, Normal albuminuria