Resistivity Index Research Articles

Evaluation of Doppler Indices for Umbilical Artery in Hypertensive Women in Third Trimester of pregnancy

Background: The hypertensive disorders affect pregnant women and can create complications for the women in last trimester of pregnancy. To assess the impact of high hypertension, doppler scan is recommended in the third trimester.
 Objective: Present explores values of PSV, EDV, S/D ratio, RI and PI among normotensive and hypertensive pregnant women during third trimester of pregnancy in Islamabad, Pakistan.
 Material and Methods: A Cross-sectional study was conducted at PIMS hospital Islamabad with objectives to evaluate doppler indices in fetal umbilical artery among hypertensive pregnant women in the third trimester of pregnancy. Data were collected from 1st February 2022 to 15th May 2022. A total of 93 pregnant women were recruited from already registered at maternal child health care center of PIMS and recommended for doppler indices scan. Toshiba Aplio 300 Ultrasound System was used for the assessment. Data about S/D ratio, RI and PI was analyzed by using IBM SPSS® software platform.
 Results: Mean Age of pregnant women in our study conducted was 26.722 ± 4.133. Also the mean gestational week for pregnant women was 32.163 ± 2.35. Doppler indices were significantly raised in hypertensive women as compared to normotensive women. Doppler indices i.e. Pulsatility Index (Mean 1.049 ± 0.312 vs 1.360 ± 0.421), Resistivity Index (Mean 0.631 ± 0.114 vs 0.743 ± 0.01), Systolic/Diastolic flow (Mean 2.672 ± 0.512 vs 3.818 ± 0.986) were increased in third trimester of hypertensive women as compared to normotensive patients.
 Conclusion: In this study, among doppler indices pulsatility index and resistivity index were identified as significant after applying null hypothesis test. Doppler ultrasound should be used to identify vascular resistance and evaluating degree of fetoplacental blood flow in hypertensive pregnant women.

Body composition and risk factors associated with sarcopenia in post-COVID patients after moderate or severe COVID-19 infections.

BackgroundPost-COVID-19 syndrome is characterized by diverse symptoms and abnormalities that persist beyond 12 weeks from the onset of acute COVID-19. Severity disease has been associated with more musculoskeletal alterations such as muscle weakness, dyspnea, and distance walking. The aim was to evaluate the impact of invasive mechanical ventilation (IMV) on body composition and investigate risk factors associated with sarcopenia in post-COVID-19 patients three months after moderate or severe COVID-19 infections.MethodsCross-sectional study. 530 patients with PCR-confirmed diagnoses of moderate to severe COVID-19, > 18 years old, oxygen saturation ≤ 93%, PaO2/FiO2 ratio < 300, who required hospitalization and were discharged were included. We excluded those who died before the follow-up visit, declined to participate, or could not be contacted.ResultsThe mean age was 53.79 ± 12.90 years. IMV subjects had lower phase angle and handgrip strength and higher impedance index, frequency of low muscle mass, and low muscle strength than those without IMV. The risk factors of sarcopenia were > 60 years of age, diabetes, obesity, IMV, and prolonged hospital stay. The multivariate model showed that age > 60 years (OR: 4.91, 95% CI: 2.26–10.63), obesity (OR: 3.73, 95% CI: 1.21–11.54), and interaction between prolonged length of hospital stay and IMV (OR: 2.92; 95% CI: 1.21–7.02) were related to a higher risk of sarcopenia.ConclusionObesity and the interaction between prolonged length of hospital stay and IMV are associated with a higher risk of sarcopenia at 3 months after severe or moderate COVID-19 infection.

Retrieving effective acoustic impedance and refractive index for size mismatch samples

In this paper, we have presented an analytical solution to extract the effective properties of acoustic metamaterials from the measured complex transmission and reflection coefficients when the metamaterial and impedance tube have different sizes. We first considered the air gap as a separate domain and modeled the problem as a bilayer metamaterial inside a duct. Then, we established theoretically that when the dimensions of an acoustic metamaterial are known, the effective properties may be derived by solving a set of eight linear equations. Finally, we assessed the proposed technique using numerical simulation data. The proposed method is shown to calculate the effective refractive index and impedance with an error of less than 1%. This method provides an efficient approach to analyze the effective properties of acoustic metamaterials of different sizes.

Ocular blood flow and retinal, choroidal, and retinal nerve fiber layer thickness in children with familial Mediterranean fever with at least five attacks.

This study aimed to evaluate ocular blood flow and, retinal, choroidal and retinal nerve fiber layer thickness in children with familial Mediterranean fever (FMF) with patients who had at least five attacks. Fifty-six patients with FMF and 56 healthy subjects were enrolled in the study. Each participant's choroidal thickness (CT) and retinal thickness (RT) measurements were performed in the foveola and at horizontal nasal and temporal quadrants within 500-μm intervals up to 1.500μm from the foveola using spectral-domain optical coherence tomography as well as the retinal nerve fiber layer thickness (RNFLT). Disc boundaries were determined manually by identifying seven points on the inner edge of the scleral ring. Following complete ophthalmological evaluation, peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) values in the central retinal artery (CRA), ophthalmic artery (OA), and nasal posterior ciliary artery (NPCA) were measured using color Doppler ultrasonography (CDU) in the left eyes of the patients diagnosed with FMF and the controls. The results were subsequently compared. No statistically significant differences were observed between the groups in terms of all RNFLT quadrant and RT measurements. All CT measurements were thinner in patients with FMF than in the controls (For Central and Temporal_1500 p = 0.01; For Temporal_500, Nasal 500 and Nasal_1000 p < 0.001; Temporal_1000 p = 0.002) except than the Nasal_1500 point. For nasal_1500 p = 0.121). The PSV and EDV values in the OA, CRA, and NPCA were significantly lower in patients with FMF compared to healthy controls (p < 0.001 for all). In contrast, the RI values of all arteries were significantly higher than in the control group (Regarding OA, CRA and NPCA RI, p = 0.003, p = 0.039, and p = 0.039, respectively). The results of this study support the idea that chronic inflammation and frequent attacks in FMF may have an effect on decreased ocular blood flow and choroidal thinning.

MO164: Is there a Place for the Resistivity and Pulsatility Index in Diabetic Nephropathy?

Abstract BACKGROUND AND AIMS Resistivity index (RI) and pulsatility index (PI) are important Doppler ultrasound (US) parameters for the evaluation of intrarenal haemodynamics. One of the pathogenetic mechanism in diabetic nephropathy (DKD) is the arteriolar hyalinosis and the interlobar arteries were proved as hallmarks for distal vasoconstriction or dilatation. Therefore, Doppler parameters are commonly used in the early detection of intrarenal vasoconstriction. We compared the results of colour Doppler parameters RI and PI in type 2 diabetic nephropathy (DKD) with hypertensive (HT) patients with proteinuria and tried to assess the risk for the disease progression. METHOD A total of 141 patients with DKD and 146 hypertensive patients were examined using an Esaote MyLab X8 eXP Ultrasound device following a precise protocol by a single examiner. All patients had proteinuria values 300–500 mg/24 h. RI and PI were measured in the interlobar arteries on three levels for each kidney, and a mean was calculated. All patients were age and sex matched and had eGFR over 45 mL/min/1.73 m2. GraphPad Prism program was used, and correlation indices were calculated. RESULTS Mean RI values were 0.71 for ND group (SD = 0.06; 95% CI), 0.66 for HT group (SD 0.06; 95% CI); t-test was highly significant (P &amp;lt; .05). Mean PI values were 1.27 for ND group (SD = 0.33; 95% CI), 1.04 for HT group (SD = 0.24), t-test was also highly significant between the two groups with P values under.05. Cut-off values for RI in DKD were above 0.72. PI values were higher with age in diabetic patients. PI and RI were highly significant in case of patients with more than 5 years from the onset of diabetes. CONCLUSION RI can be considered a suggestive parameter for the presence of DN. PI alongside RI correlated with the duration of diabetes, age and incipient DN. We recommend the use of RI in the early evaluation of DKD. Although Doppler US examination is time-consuming, it can be easily performed in non-obese and compliant patients.

Two-megahertz impedance index prediction equation for appendicular lean mass in Korean older people

BackgroundWhole-body bioelectrical impedance analysis (BIA) has been accepted as an indirect method to estimate appendicular lean mass (ALM) comparable to dual-energy X-ray absorptiometry (DXA). However, single or limited frequencies currently used for these estimates may over or under-estimate ALM. Accordingly, there is a need to measure the impedance parameter with appendicular lean-specific across multiple frequencies to more accurately estimate ALM. We aimed to validate muscle-specific frequency BIA equation for ALM using multifrequency BIA (MF-BIA) with DXA as the reference.Methods195 community-dwelling Korean older people (94 men and 101 women) aged 70 ~ 92y participated in this study. ALM was measured by DXA and bioimpedance measures at frequencies of 5 kHz ~ 3 MHz were assessed for independent predictive variables. Regression analyses were used to find limb-specific frequencies of bioimpedance, to develop the ALM equations and to conduct the internal cross-validation. The six published equations and the final equation of MF-BIA were externally cross-validated.Results195 participants completed the measurements of MF-BIA and DXA. Using bivariate regression analysis, the 2 MHz impedance index explained R2 = 91.5% of variability (P < 0.001) in ALM and predictive accuracy of standard error of estimate (SEE) was 1.0822 kg ALM (P < 0.001). Multiple stepwise regression analysis obtained in the development group had an adjusted R2 of 9.28% (P < 0.001) and a SEE of 0.97 kg ALM. The cross-validation group had no significant difference between the measured ALM and the predicted ALM (17.8 ± 3.9 kg vs. 17.7 ± 3.8 kg, P = .486) with 93.1% of R2 (P < 0.001) and 1.00 kg ALM of total error. The final regression equation was as follows: ALM = 0.247ZI@2 MHz + 1.254SEXM1F0 + 0.067Xc@5 kHz + 1.739 with 93% of R2 (P < 0.001), 0.97 kg ALM of SEE (Subjective Rating as “excellent” for men and “very good” for women). In the analysis of the diagnostic level for sarcopenia of the final regression, the overall agreement was 94.9% (k = 0.779, P < 0.001) with 71.4% of sensitivity, 98.8% of specificity, 91.3 of positive prediction value and 95.3% of negative prediction value.ConclusionThe newly developed appendicular lean-specific high-frequency BIA prediction equation has a high predictive accuracy, sensitivity, specificity, and agreement for both individual and group measurements. Thus, the high-frequency BIA prediction equation is suitable not only for epidemiological studies, but also for the diagnosis of sarcopenia in clinical settings.

Resistivity and pulsatility indexes in feline kidney disease: a systematic review.

Doppler ultrasonography is used in the evaluation of hemodynamics, and the resistivity (RI) and pulsatility (PI) indexes provide information about resistance to blood flow within a vessel. This systematic review was carried out to evaluate renal RI and PI in clinically healthy and nonsedated cats and as well as their usefulness in the evaluation of kidney disease in cats. An electronic search in the PubMed, Scopus, and Web of Science databases was carried out using the terms "resistive index" or "resistivity index" or "pulsatility index;" "Doppler;" "renal" or "kidney;" and "cat" or "feline" in titles, abstracts, and keywords. Variables of interest related to experimental model features, research methods, and technical resources were extracted from the studies. The methodological quality was assessed with SYRCLE's risk of bias tool. Thus, 14 studies involving healthy and sick cats were selected. Interestingly, the upper limits estimated for both RI and PI varied among studies. The upper limits of renal RI for healthy cats varied between 0.64 and 0.72, while for PI, the values varied from 1.06 to 1.29. A limited number of studies evaluated cats with kidney disease. In most studies, RI values of kidneys with different conditions were significantly different from kidneys of healthy animals, indicating that RI values increase with kidney disease. The parameters body weight, heart rate, and age seem to influence the RI values. Standardized studies regarding its realization and description are still necessary to define normal values and analyze its applicability in the clinical diagnostic routine.

Characteristics of the Maternal Jugular Venous Pulse Waveform by Combined Doppler-Electrocardiogram Assessment.

Standardized combined Doppler-electrocardiogram assessment was performed longitudinally at three different locations of internal jugular veins between 12 wk of gestation and 6 wk postnatally in 24 uncomplicated pregnancies. All images were classified as typical or non-typical based on the presence of the physiologic deflections A, X, H and C. Linear mixed models with random intercepts of typical images were used to investigate gestational changes in venous pulse transit time and venous impedance index. Unequivocal identification of venous pulse transit time and venous impedance index was possible in 2617 of 3798 (69%) and 2234 of 3798 (59%) images, respectively. The best identification rate (80%, 1018/1266) was at the right distal internal jugular vein. Venous pulse transit time increased with gestational age at all locations; venous impedance index decreased at the right sided internal jugular vein. Maternal jugular venous pulse waveform by combined Doppler-electrocardiogram allows unequivocal identification of A-deflection and calculation of venous pulse transit time and venous impedance index in around two-thirds of assessments, with the highest success rate at the right distal internal jugular vein. Gestational evolutions of venous pulse transit time and venous impedance index are similar to those reported at the level of renal interlobar and hepatic veins.

Study of testicular vascularity after totally extraperitoneal repair in inguinal hernia

Background: Totally extra-peritoneal repair is one of the commonly used method for repair of inguinal hernia which is gaining popularity in recent days. Its effect on testicular vascularity has not been well established. The objective of this study was to study testicular vascularity following totally extra-peritoneal repair [TEP] in inguinal hernia.Methods: This study was prospective observational study performed on patients with inguinal hernia undergoing TEP where testicular USG doppler parameters like peak systolic velocity (PSV), end diastolic velocity (EDV), resistivity index (RI) and pulsatilty index (PI) were measured on pre-operative day, on 3rd postoperative day and 90th postoperative day, and serum values of FSH, LH and Testosterone were measured preoperatively and 90th postoperative day and these values were compared.Results: 42 patients were included in this study. There was no statistically significant difference in the values of PSV (p=0.497), EDV (p=0.981), RI (p=0.290) and PI (p=0.733) between preoperative value, 3rd postoperative day, and 90th postoperative day. There was no statistically significant difference in the serum values of FSH (p=0.376), LH (p=0.101) and Testosterone (p=0.506) between preoperative and 90th postoperative day level.Conclusions: It was concluded that totally extra-peritoneal repair (TEP) do not affect testicular perfusion. However large scale multi-institute trails with bigger sample size is required to find out effect of TEP on testicular vascularity.

Interleukin 37; a possible marker of arterial stiffness in Behçet's disease

BackgroundInterleukin 37 (IL-37) is an anti-inflammatory cytokine previously studied in Behçet's disease (BD) and atherosclerosis. However, little is known about its relation to macro and microcirculations in BD. Previous studies relied mainly on common carotid artery (CCA) intima-media thickness (IMT) and ankle brachial index (ABI) to study atherosclerosis in BD with conflicting results. This study evaluated flow parameters of CCA, ABI and nailfold videocapillaroscopy in relation to serum IL-37 in BD. MethodsForty BD patients and 30 healthy controls were included. IMT, peak-systolic, end-diastolic velocities, resistivity index of CCA and ABI were measured by duplex ultrasound. Capillary loop, length, diameter and morphology were recorded by nailfold videocapillaroscopy. Serum IL-37 levels were measured using enzyme-linked immunosorbent assay (ELISA). ResultsCompared to controls, patients had higher mean CCA IMT (p < 0.0001), resistivity index (p < 0.001) and peak-systolic velocity (p=0.09) and lower mean CCA end-diastolic velocity (p=0.002), capillary loop, length, arterial, venous limbs diameter and serum IL-37 (p < 0.001). Patients with ABI ≥ 1.4 “indicating stiff arteries” had higher serum IL-37 (p < 0.05 on left, p>0.05 right sides). Serum IL-37 correlated negatively with left CCA end-diastolic velocity “denoting atherosclerosis” and positively with left posterior tibial artery ABI and CRP (p < 0.03) “denoting inflammation”. Multiple regression analysis showed only association with left CCA end-diastolic velocity. ConclusionsIL-37 may be related to arterial stiffness in BD and could be used as a possible marker of arteriosclerosis in the disease for further investigations. Changes of CCA peak-systolic, end-diastolic velocities, resistivity index and IMT refer to increased atherosclerosis in larger elastic arteries. In smaller muscular “crural” arteries, vasculitis with possible medial disease may be more evident.

Оценка возрастных изменений параметров глазного кровотока диска зрительного нерва методом лазерной спекл-флоуграфии

The most common eye diseases, including glaucoma and diabetic retinopathy, are associated with impaired perfusion of the eye. To date, LSFG is a reliable method for quantifying ocular circulation. Purpose. To assess the ocular blood flow age- related changes using Laser Speckle Flowgraphy (LSFG). Material and methods. This cross-sectional study included 90 eyes of 45 healthy, non-smoking volunteers, between 20 to 75 years old. LSFG instrument was applied to measure ocular blood flow at the optic nerve head. The mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for different regions of the ONH. Three parameters of ocular perfusion derived from the pulse-waveform analysis of MBR for big vessels (MV) and microcirculatory bad (MT) including blowout time (BOT), blowout score (BOS) and resistivity index (RI) were also recorded. Results. Artifact-free LSFG images meeting the quality criteria for automated image analysis were obtained. Measurements of MBR showed excellent repeatability. MBR-related blood flow indices exhibited significant age dependence (p&lt;0.05). BOT, BOS and RI changes also analysed. Conclusion. LSFG represents a reliable method for the quantitative assessment of ocular blood flow. Our data affirms that the LSFG-parameters may be useful biomarkers of ocular perfusion for age-related and patologic changes. Key words: ocular perfusion, microcirculation, optic nerve disc, laser speckle flowgraphy, LSFG, glaucoma, diabetic retinopathy

Estimating geoacoustic properties of sediments with a wide grain-size distribution using sediment organic content and the viscous grain shearing model

Interstitial organic matter (OM) is a ubiquitous constituent of marine sediment, particularly prevalent in sediments with significant silt/clay fractions, and is often quantified across a wide range of disciplines. OM suspends silt and clay particles in the sediment matrix, adsorbs onto mineral surfaces, and resides primarily between mineral contacts, all of which are hypothesized to alter geoacoustic properties, yet OM has not been included in sediment acoustics models. Recent studies have shown that OM content (OC) correlates well with sediment geoacoustic properties, such as porosity and index of impedance, from sediments found in the Baltic Sea to seagrass-bearing sediments in Texas to mud banks in Brazil. In Mobile Bay, Alabama, OC correlated well not only with porosity and index of impedance, but also with grain-shearing coefficients described by the viscous grain shearing (VGS) model. Using empirical regressions derived from a subset of the Mobile Bay biogeoacoustic data and VGS, OC will be used to estimate geoacoustic properties of Mobile Bay sediments with a wide grain-size distribution. The efficacy and potential of using OC to predict sediment geoacoustic properties (and vice versa) in Mobile Bay and in other sediments with similar composition will be discussed. [Work supported by ONR.]

A study on effect of diabetes mellitus and hypertension on ocular blood flow by colour doppler ultrasonography

Background: Diabetes mellitus (DM) and hypertension (HT) have been the two major medical and public health issues for over 40 years worldwide. Colour doppler imaging (CDI) is widely used to evaluate ocular circulation. It is non-invasive, safe, and useful tool, most commonly used to investigate circulatory parameters in retrobulbar blood vessels. The aim was to study ocular blood flow (OBF) velocity in the ophthalmic artery (OA), central retinal artery (CRA) and central retinal vein (CRV) in patients with DM and HT by CDI. Materials and methods: A cross-sectional observational study was done for 6 months (June 2021–November 2021) on 40 patients of age 40 years and above with DM and/or HT of a minimum 6 months duration. Retrobulbar circulation was assessed in all subjects bilaterally. Subjects were further divided into groups with or without retinopathy. Results: Of the total number of 40 participants, 26 (65%) were male, and 14 (35%) were female. 16 (40%) participants were diabetics, 8 (20%) were hypertensive, and 16 (40%) had both DM and HT. 57.5% were diagnosed with retinopathy changes. The mean values of the pulsatile index (PI) were: 1.23 in patients with DM, 1.30 in patients with HTN, and 1.33 in patients with DM and HTN. Conclusion: Our study showed reduced blood flow velocity and increased resistivity index (RI) in patients with DM and/or HT. Significant changes were noted in retrobulbar blood flow in patients with retinopathy. These results can potentially provide prognostic values in times to come regarding altered OBF even before retinopathy develops.

Comparison of Placental Elasticity and Different Spectral Doppler Indices in Normal and Intrauterine Growth Restricted Fetuses

Objective: Comparison of Placental Elasticity and different spectral Doppler indices in normal and intrauterine growth restricted fetuses to establish efficacy of shear wave elastography in early detection of Intrauterine Growth Restricted (IUGR). Design: Cross sectional comparative. 290 pregnant women previously diagnosed by ultrasound as normal and intrauterine growth restriction fetuses which were included in this study, placental elasicity in both groups was evalauted by SWE (shearwave elastography) and compared. Methods: Primarily both groups were scanned for grayscale and Color Doppler ultrasonography in which we took the measurements of resistivity and pulsatility indices of umbilical artery (UA), uterine artery and MCA (middle cerebral artery). In these groups placental elasticity was evaluated by SWE .The ratios of strain were compared between both groups. Statistical study was carried out by using Mann-Whitney test. Cut-off values for elasticity were analyzed by plotting receiver operative characteristic curve (ROC), sensitivity. Specificity and DA&#x0D; (diagnostic accuracy) for IUGR were designed established on Shear wave elastography measurements. Results: The mean placental elasticity in intrauterine growth restriction (IUGR) and in normal groups was 28.71+7.28 and 5.64+1.53, respectively while in the IUGR group median placental elasticity was 27+7 and 5.50+2 with statistically elevated median among patients in the IUGR group (P

Evaluation of the impact of childhood obesity on retrobulbar hemodynamics and retinal microvasculature.

To evaluate changes in retrobulbar ocular blood flow parameters by using Colour Doppler Imaging (CDI) and changes in foveal microvasculature by using Optical Coherence Tomography Angiography (OCTA) in pediatric obese patients and to compare them with a group of healthy children. Children diagnosed with obesity without hypertension and diabetes (39 subjects, obese group) and age-matched healthy controls (26 subjects, control group) underwent CDI and OCTA imaging. Peak systolic velocity, end-diastolic velocity and resistivity index from ophthalmic, central retinal and posterior ciliary arteries on CDI; superficial and deep capillary plexus vascular density and foveal avascular zone area on OCTA imaging were obtained in each group. Central foveal and subfoveal choroidal thicknesses were also measured. CDI and OCTA parameters were compared between two groups. Peak systolic and end-diastolic velocities were found to be significantly lower in obese children than in controls in all three examined arteries (p < 0.05). Resistivity index values were similar between the groups. OCTA imaging did not reveal significant changes in superficial and deep capillary plexus vascular densities and foveal avascular zone area across analysed retinal regions between the groups. Subfoveal choroid was thicker in obese group than in control group (325.89 ± 52.77 µm vs. 304.52 ± 21.76 µm, p = 0.04). An apparent decrease was present in retrobulbar hemodynamics in obese children. This arises the possibility of early ocular macrovascular compromise rather than retinal microvascular impairment in childhood obesity.

Resistivity index in the diagnosis and assessment of loss of renal function in diabetic nephropathy.

The aim of this study was to determine the haemodynamics of the intrarenal arteries from the relationship between resistivity index (RI) and kidney function, and to identify the predictors of high RI among patients with diabetic nephropathy (DN) and those with diabetes mellitus (DM) without DN. This was a cross-sectional survey of 133 participants, comprising 40 subjects with DM without DN, 53 with DM with DN and 40 healthy controls. Information obtained was demographics, lifestyle, medical and medication histories, while anthropometric and blood pressure measurements were taken. Albuminuria and estimated glomerular filtration rate were determined and RI was measured using a Doppler ultrasound scan. The mean intrarenal artery RIs were higher among the patients with DM without DN (0.60 ± 0.04) and the group with DM with DN (0.61 ± 0.04) than in the controls (0.56 ± 0.04) (p = 0.02). Glycated haemoglobin (HbA1c) predicted high RI in the DM without DN group (OR 2.81; CI: 1.73-9.03) while hypertension (OR 3.60; CI: 1.06-12.22) predicted high RI in the DM with DN group. Elevated intrarenal artery RI was prevalent among patients with DM without DN and those with DM with DN, while elevated HbA1c level and hypertension predicted elevated RI in subjects with DM without DN and those with DM with DN.

Correlation between the range of motion of the tibiotarsal joint and blood circulation in the lower limbs in diabetic individuals.

The aim of this study was to evaluate the relationship between the range of motion and lower-limb hemodynamic indices in the tibiotarsal joint of individuals with diabetic neuropathy. Twenty volunteers of both sexes, with a mean age of 61.45±7.05 years, were diagnosed with type 2 diabetes mellitus and diabetic peripheral neuropathy. Arterial blood flow was assessed using Doppler ultrasound, and the variables such as average velocity, pulsatility index, and resistivity index were also evaluated. A range of dorsiflexion and plantar flexion joint movements were assessed using digital goniometry before and after exercise. Data distribution was assessed using the Shapiro-Wilk test, followed by Pearson's correlation for normal data and Spearman's correlation for non-normal data, in order to verify the association between variables. A moderate correlation was found between dorsiflexion and pulse rate on two occasions before (rs=0.497) and after initial evaluation (rs=0.511). A low correlation was found between plantar flexion and mean velocity (rs=-0.357), pulsatility index (rs=0.439), and resistivity index (rs=0.328); dorsiflexion and mean velocity (rs=0.374), pulse rate (rs=0.332), and resistance index (rs=0.327) before evaluation, and peak (rs=0.346) was observed after the evaluation of blood circulation. There is a correlation between the range of motion of the tibiotarsal joint and the blood circulation of diabetics, ranging from moderate to poor for the different variables evaluated.

Correlation of resistive index of main renal artery and inter-lobar artery with degree of hydronephrosis.

Objective: To study the correlation of resistive index of main renal artery and inter-lobar artery with degree of hydronephrosis. For the purpose of this study data collection was carried through different research works conducted previously regarding hydronephrosis and its effects on the resistivity index of renal arteries. Study Design: Systemic Review. Setting: Radiology Research Section, University of Lahore. Period: September 2018 to May 2020. Material &amp; Methods: Research was conducted with the help of keywords. One hundred and three articles were found at initial stage. A table was designed for data collection purpose including the information such as author of article, year of research, type of hydronephrosis, number of patients, and the resistive index of renal arteries. The data included both male and female patients of any age suffering from hydronephrosis of any origin and no area or time limitation was applied. Results: Pooling results of this systematic review depicts that the researchers conducted various researches addressing the cause of hydronephrosis, the effect of type of hydronephrosis on the resistive index, difference between resistivity index of obstructive and non-obstructive hydronephrosis, level of obstruction and its effect on RI of the renal artery, factors that influence RI other than renal in origin but not a single research conducted on human subject represents the correlation of different grades or degrees of hydronephrosis with either main renal artery or inter-lobar arteries. Out of 17 articles, 8 (47%) articles discuss the resistive index for both obstructive and non-obstructive hydronephrosis while remaining 9 (53%) articles discuss only the mean resistive index for the obstructed kidney. Conclusion: Although renal resistive index is the parameter which is influenced by a variety of other factors such as age of patient, plasma renin level, and the simultaneous presence of certain diseases like hypertension, cardiac diseases, diabetes mellitus, and renal disorders. The presence of any of these factors may rise the RI values even if there is no renal obstruction. Yet different research mainly shows that the values of RI are high i.e. &gt;0.70 in case of obstructed kidney while generally the values of RI are &lt;0.70 in case of none obstructed kidney.

Microscopic Conductivity Mechanism and Saturation Evaluation of Tight Sandstone Reservoirs: A Case Study from Bonan Oilfield, China

Core samples of the tight sandstone reservoir in the Bonan Oilfield were analyzed by using multiple petrophysical experimental techniques, then a multi-scale three-dimensional digital rock model was constructed. The pore structure parameters of tight sandstone and homogeneous Berea sandstone were compared. The electrical simulation method based on the digital rock model was utilized to quantitatively reveal the influence of five micro-pore structure parameters (pore size, throat size, pore-throat size, coordination number, and shape factor) on the rock’s electrical properties. In addition, the saturation of tight sandstone reservoirs was evaluated in combination with the three-component automatic mixed-connection conductivity model. The results show that the “non-Archie” phenomenon in sandstone is obvious, which is mainly caused by the small radius of the maximum connected pore throat and the complex structure of the pore throat. We noted that: with an increase in pore radius, throat radius, and coordination number, the formation factor decreases and tends to be stable; the pore-throat size increases and the formation factor decreases in the form of power function; the shape factor increases, and the formation factor increases; the larger the pore–throat ratio and shape factor, the greater the resistivity index; with an increase in coordination number, the resistivity index decreases; and the pore-throat size has no effect on the resistivity index. The calculation accuracy of oil saturation is improved by 6.54% by constructing the three-component automatic mixed-conductivity saturation model of tight sandstone.

Comprehensive assessment of systemic arteriosclerosis in relation to the ocular resistive index in acute coronary syndrome patients

This study aimed to investigate the relationship between ocular vascular resistance parameters, evaluated by laser speckle flowgraphy (LSFG), and systemic atherosclerosis, renal parameters and cardiac function in acute coronary syndrome (ACS) patients. We evaluated 53 ACS patients between April 2019 and September 2020. LSFG measured the mean blur rate (MBR) and ocular blowout time (BOT) and resistivity index (RI). 110 consequent patients without a history of coronary artery disease who visited ophthalmology as a control group. Significant positive correlations were observed between ocular RI and systemic parameters in ACS patients, including intima-media thickness (r = 0.34, P = 0.015), brachial-ankle pulse-wave velocity (r = 0.41, P = 0.002), cystatin C (r = 0.32, P = 0.020), and E/e’ (r = 0.34, P = 0.013). Ocular RI was significantly higher in the ACS group than in the control group in male in their 40 s (0.37 ± 0.02 vs. 0.29 ± 0.01, P < 0.001) and 50 s (0.36 ± 0.02 vs. 0.30 ± 0.01, P = 0.01). We found that the ocular RI was associated with systemic atherosclerosis, early renal dysfunction, and diastolic cardiac dysfunction in ACS patients, suggesting that it could be a useful non-invasive comprehensive arteriosclerotic marker.