Ultrasound Estimation Research Articles

A prospective blinded diagnostic accuracy study to assess the accuracy of fetal weight estimation at term by clinical method using Leopold’s maneuvers and ultrasonography in predicting the actual birth weight

ABSTRACT Context: Over-medicalization of normal pregnancy is associated with unnecessary inductions of labor leading to operative deliveries. In a busy outpatient department (OPD) or low-resource setup where ultrasound availability, experience, and cost will be a concern, routine ultrasound at term can be avoided if the clinical estimation of fetal weight is more or less equal to the actual birth weight. Aims: To assess the reliability and validity of fetal weight estimation at term by ultrasound and clinical estimation. Settings and Design: A prospective study of diagnostic accuracy was done over a period of 1.5 years in a tertiary hospital, which included 100 women with term singleton pregnancies admitted in obstetric wards or labor room. Methods and Material: To find out the agreement between actual birthweight and ultrasound fetal weight interclass correlation coefficient (ICC) was used. Mean difference plots (Bland–Altman plots) were done. The mean percentage error was compared with the consultant estimate and registrar estimate across groups. The sensitivity, specificity, and predictive values by clinical and ultrasound estimate were calculated for actual birth weight ≤ 2.5 kg. Results: Both methods of fetal weight estimation have moderate reliability in predicting the actual birth weight. The sensitivity of identifying birthweight < 2.5 kg babies by ultrasound was slightly higher. For birth weight less than 2.5 kg, there was an overestimation of fetal weight by clinical estimation done by postgraduate with mean percentage error being statistically significant as compared with ultrasound estimation. Conclusions: In a developing country like ours where ultrasound is not readily available in all healthcare setups, the clinical method is an easy, cost-effective, simple one that can be used by all medical professionals after adequate training.

Application en routine des résultats d’un essai randomisé : performance de l’échographie en pratique courante pour le dépistage de la macrosomie fœtale

ObjectiveTo evaluate the performance of ultrasound at 36 weeks of gestation for screening fetal macrosomia according to the criteria of the randomized “DAME” trial. MethodRetrospective observational study over 2 years in a type 3 maternity hospital. The primary outcome was birth weight above the 97th percentile on Audipog birth weight curves. The sensitivity, specificity, positive and negative predictive value of ultrasound at 36 SA for predicting macrosomia were calculated. For each patient, the absolute value of the difference between actual and estimated weight [EPF difference=(Birth weight − Estimated weight)/Birth weight] was calculated. Among undetected macrosomic newborns (≥97th Audipog percentile), risk factors associated with misdiagnosis were investigated (false negatives versus true positives). ResultsUltrasound estimation of fetal weight at 36 SA to detect fetal macrosomia had a sensitivity of 43.7% and a specificity of 82.1%. With a positive predictive value for ultrasound of 36,9% and a negative predictive value of 85.8%. The mean absolute value of the difference between estimated and actual birth weight was 287g (95% CI [115–409]), with a mean relative difference of 6.8% (95% CI [3.0–11.3]). A relative difference of less than 10% between the estimated weight and the birth weight was found in 68.5% of the patients. Among macrosomic newborns (≥97th percentile), a third-trimester estimated fetal weight at or above the 90th percentile, along with a history of fetal macrosomia in a previous pregnancy, reduced the risk of false negatives in the screening ultrasound at 36 weeks of gestation. ConclusionUltrasound performed at 36 weeks’ gestation in a population targeted for suspected fetal macrosomia in routine practice has moderate sensitivity and positive predictive value. It would be timely for teams also applying this protocol to share their results, in order to verify whether or not our findings can be generalized to a larger scale.

Novel Quantitative Liver Steatosis Assessment Method With Ultrasound Harmonic Imaging.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent liver disorder in Western countries, with approximately 20%-30% of the MASLD patients progressing to severe stages. There is an urgent need for noninvasive, cost-effective, widely accessible, and precise biomarkers to evaluate liver steatosis. This study aims to assess and compare the diagnostic performance of a novel reference frequency method-based ultrasound attenuation coefficient estimation (ACE) in both fundamental (RFM-ACE-FI) and harmonic (RFM-ACE-HI) imaging for detecting and grading liver steatosis. An Institutional Review Board-approved prospective study was carried out between December 2018 and October 2022. A total number of 130 subjects were enrolled in the study. The correlation between RFM-ACE-HI values and magnetic resonance imaging proton density fat fraction (MRI-PDFF), as well as between RFM-ACE-FI values and MRI-PDFF were calculated. The diagnostic performance of RFM-ACE-FI and RFM-ACE-HI was evaluated using receiver operating characteristic (ROC) curve analysis, as compared to MRI-PDFF. The reproducibility of RFM-ACE-HI was assessed by interobserver agreement between two sonographers. A strong correlation was observed between RFM-ACE-HI and MRI-PDFF, with R = 0.88 (95% confidence interval [CI]: 0.83-0.92; P < .001), while the correlation between RFM-ACE-FI and MRI-PDFF was R = 0.65 (95% CI: 0.50-0.76; P < .001). The area under the ROC (AUROC) curve for RFM-ACE-HI in staging liver steatosis grades of S ≥ 1 and S ≥ 2 was 0.97 (95% CI: 0.91-0.99; P < .001) and 0.98 (95% CI: 0.93-1.00; P < .001), respectively, and 0.76 (95% CI: 0.65-0.85) and 0.80 (95% CI: 0.70-0.88) for RFM-ACE-FI, respectively. Great reproducibility was achieved for RFM-ACE-HI, with an interobserver agreement of R = 0.97 (95% CI: 0.94-0.99; P < .001). The novel RFM-ACE-HI method offered high liver steatosis diagnostic accuracy and reproducibility, which has important clinical implications for early disease intervention and treatment evaluation.

Ultrasonographic estimation of kidney size in adult Bangladeshi population without known renal disease: a preliminary report

Background: The kidney size of a patient is a valuable diagnostic parameter in clinical practice. Renal size varies with age, gender, body mass index (BMI), pregnancy, race and co-morbid conditions like diabetes mellitus (DM) and hypertension (HTN). Measurements of renal dimensions can be carried out by using different modern techniques like ultrasonography (USG), computed tomography (CT) scan and magnetic resonance imaging (MRI). Out of these modalities USG is choice because of its simplicity, inexpensive, easily available, non-invasive and easy reproducibility. There is no established nomogram for renal size in the Bangladeshi population. Aim of the study was to determine the ultrasonographic renal size in adult Bangladeshi population with no known renal disease and to correlate renal size with age, gender and BMI. In addition, we assess whether hypertension and diabetes mellitus affect renal size. Methods: This cross-sectional study was done in BIRDEM General Hospital and included 55 patients with age &gt;18 years over 6 month period. Study population were not known to have renal disease documented by urine routine microscopy, spot urine for albumin creatinine ratio (ACR), serum creatinine and USG. Their body weight, height and BMI were calculated along with duration of DM and HTN. Analysis was done for differences due to age, gender and laterality. The correlation of renal dimensions with anthropometric parameters were also done. Results: A total of 55 patients were analyzed. There were 19 (34.5%) male and 36 (65.5%) female. The mean age was 46±.10 years. There mean weight, height and BMI were 61 ± 11 kg, 1.54±.069 meter, 25.7 ± 4.8 kg/m2 respectively. In total population 34.5% (19) were diabetic and 32.5% (18) were hypertensive. The means of length, width and parenchymal thickness (PT) of right kidneys (RK) were 10.1 ± 0.87, 4.2 ± 0.67 and 1.4± 0.32 cm respectively. The means of length, width and PT of left kidneys (LK) were 10.3 ± 0.89, 4.5 ± 0.49 and 1.5 ± 0.32 cm respectively. Measurements were significantly higher in LK than those of RK respectively (p=.003, p&lt;.001 and p=.041). There were significant differences in kidney length and PT between sex and age. There were also significant differences in kidney length and PT between subjects of higher BMI, long duration of DM and HTN. The correlation between renal length and weight showed a positive correlation (r = 0.16, p &lt; 0.023). Conclusion: The variation of parameters of both kidneys varies on gender, age, obesity, comorbidity like DM &amp; HTN and with their duration. Length of both kidneys depends on body weight. Further study needed with large samples. BIRDEM Med J 2024; 14(3): 151-157

Accuracy of supervised measurement of fetal weight in a residency program.

To evaluate the accuracy of ultrasound estimates of fetal weight made by residents. A cross-sectional study was conducted on consecutive pregnancies attended in an obstetric ward. All participants provided their consent to participate. Inclusion criteria were singleton pregnancies with ultrasound evaluation and delivery within 14 days. Congenital abnormalities and stillbirths were excluded. Ultrasound scans were performed by two residents, one observer per subject, following standardized methodology and supervised by senior staff. Fetal weight was calculated using the four-parameter Hadlock 1985 formula. Birth weight was measured using a standard clinical scale. Bland-Altman and mixed-effects analyses were performed. In a 6-month period, 95 gestations were recruited at 30-41 weeks, and birth weights ranged from 1200 to 4080 g. The bias between methods was -28 g (CI95%, -74 to 18) with 95% limits of agreement of ±440 g. The 95% deviation between methods was of ±16%. Parity had the most significant effect on the bias between methods; operator and maternal weight had no significant effect. Supervised measurement of fetal weight by residents demonstrated high accuracy. Parity bias may be associated with visceral fat deposition independent of maternal weight gain. A methodology for medical evaluation is presented.

Ultrasound normalized cumulative residual entropy imaging: Theory, methodology, and application

Background and Objective:Ultrasound information entropy imaging is an emerging quantitative ultrasound technique for characterizing local tissue scatterer concentrations and arrangements. However, the commonly used ultrasound Shannon entropy imaging based on histogram-derived discrete probability estimation suffers from the drawbacks of histogram settings dependence and unknown estimator performance. In this paper, we introduced the information-theoretic cumulative residual entropy (CRE) defined in a continuous distribution of cumulative distribution functions as a new entropy measure of ultrasound backscatter envelope uncertainty or complexity, and proposed ultrasound CRE imaging for tissue characterization. Methods:We theoretically analyzed the CRE for Rayleigh and Nakagami distributions and proposed a normalized CRE for characterizing scatterer distribution patterns. We proposed a method based on an empirical cumulative distribution function estimator and a trapezoidal numerical integration for estimating the normalized CRE from ultrasound backscatter envelope signals. We presented an ultrasound normalized CRE imaging scheme based on the normalized CRE estimator and the parallel computation technique. We also conducted theoretical analysis of the differential entropy which is an extension of the Shannon entropy to a continuous distribution, and introduced a method for ultrasound differential entropy estimation and imaging. Monte-Carlo simulation experiments were performed to evaluate the estimation accuracy of the normalized CRE and differential entropy estimators. Phantom simulation and clinical experiments were conducted to evaluate the performance of the proposed normalized CRE imaging in characterizing scatterer concentrations and hepatic steatosis (n = 204), respectively. Results:The theoretical normalized CRE for the Rayleigh distribution was π/4, corresponding to the case where there were ≥10 randomly distributed scatterers within the resolution cell of an ultrasound transducer. The theoretical normalized CRE for the Nakagami distribution decreased as the Nakagami parameter m increased, corresponding to that the ultrasound backscattered statistics varied from pre-Rayleigh to Rayleigh and to post-Rayleigh distributions. Monte-Carlo simulation experiments showed that the proposed normalized CRE and differential entropy estimators can produce a satisfying estimation accuracy even when the size of the test samples is small. Phantom simulation experiments showed that the proposed normalized CRE and differential entropy imaging can characterize scatterer concentrations. Clinical experiments showed that the proposed ultrasound normalized CRE imaging is capable to quantitatively characterize hepatic steatosis, outperforming ultrasound differential entropy imaging and being comparable to ultrasound Shannon entropy and Nakagami imaging. Conclusion:This study sheds light on the theory and methodology of ultrasound normalized CRE. The proposed ultrasound normalized CRE can serve as a new, flexible quantitative ultrasound envelope statistics parameter. The proposed ultrasound normalized CRE imaging may find applications in quantified characterization of biological tissues. Our code will be made available publicly at https://github.com/zhouzhuhuang.

Historical Assessment, Practical Management, and Future Recommendations for Abnormal Amniotic Fluid Volumes.

Objective: The purpose of this review is to examine the evidence that defines normal and abnormal amniotic fluid volumes (AFVs) and current recommendations on the management of abnormalities of AFV. Methods: The studies establishing normal actual AFVs and the ultrasound estimates used to identify normal and abnormal AFVs were evaluated. Recommendations from national and international organizations were reviewed for guidance on the definitions and management of abnormal AFVs. Results: A timeline of the development of the thresholds that define abnormal AFVs was created. Recommendations from 13 national and international guidelines were identified, but the definitions and management recommendations for abnormal AFVs varied considerably between groups. An algorithm for the management of oligohydramnios and polyhydramnios was developed. Knowledge gaps and the structure of future studies were examined. Conclusions: Assessment of AFV is performed multiple times per day in antenatal clinics and hospitals. Current recommendations on defining and managing abnormal AFVs differ between national and international organizations. We have proposed algorithms to assist in the management of abnormal AFVs until further studies can be undertaken.

Point-of-Care Ultrasound for Gastric Volume Measurement in a Pediatric Patient-Look Beyond the Antrum: A Case Report.

Gastric ultrasound estimates stomach contents in perioperative patients. A 10-year-old boy with abdominal rhabdomyosarcoma, who received abdominal radiation, developed gastroparesis and was scheduled for endoscopic gastrointestinal pyloric dilation. Point-of-care gastric ultrasound revealed gastric antral cross-sectional area of 6.5 cm2 (estimated gastric content ~30 mL). However, dynamic right-to-left ultrasound revealed more hypoechoic material in the fundus of the stomach. On induction ~125 mL of stomach contents was suctioned. Antral measurements may not accurately predict the stomach contents in the setting of a stiff/fixed antrum. Scanning from antrum to fundus determined contents more accurately, especially with a prior history of abdominal radiation.

Comparing Fetal Weight Estimates in the Third Trimester: Clinical Examination Findings, Ultrasonographic Estimation, and Actual Birth Weight

Comparing Fetal Weight Estimates in the Third Trimester: Clinical Examination Findings, Ultrasonographic Estimation, and Actual Birth Weight

Comparison of methods for estimating Young’s moduli of mortar specimens

Precisely estimating material parameters for cement-based materials is crucial for assessing the structural integrity of buildings. Both destructive (e.g., compression test) and non-destructive methods (e.g., ultrasound, computed tomography) are used to estimate Young’s modulus. Since ultrasound estimates the dynamic Young’s modulus, a formula is required to adapt it to the static modulus. For this formulas from the literature are compared. The investigated specimens are cylindrical mortar specimens with four different sand-to-cement mass fractions of 20%, 35%, 50%, and 65%. The ultrasound signals are analyzed in two distinct ways: manual onset picking and full-waveform inversion. Full-waveform inversion involves comparing the measured signal with a simulated one and iteratively adjusting the ultrasound velocities in a numerical model until the measured signal closely matches the simulated one. Using computed tomography measurements, Young’s moduli are semi-analytically determined based on sand distribution in cement images. The reconstructed volume is segmented into sand, cement, and pores. Young’s moduli, as determined by compression tests, were better represented by full-waveform inversions (best RMSE = 0.34 GPa) than by manual onset picking (best RMSE = 0.87 GPa). Moreover, material parameters from full-waveform inversion showed less deviation than those manually picked. The maximal standard deviation of a Young’s modulus determined with FWI was 0.36, while that determined with manual picking was 1.11. Young’s moduli from computed tomography scans match those from compression tests the closest, with an RMSE of 0.13 GPa.

Estimation of fetal weight at term by clinical and sonographic assessment and its correlation with the birth weight – A prospective cohort study in a tertiary care hospital

Estimation of fetal weight is necessary to decide on the time and route of delivery. Different clinical and ultrasound methods for estimating fetal weight are followed by different institutions. Antenatal assessment of fetal weight is necessary to achieve better feto-maternal outcomes. The objectives of this study were: (a) fetal weight estimation by ultrasound (Hadlock’s formula) and clinical methods (Johnson’s formula and Dare’s formula) and (b) to compare them with the actual weight of the baby after birth. A prospective cohort study was conducted in a tertiary care centre at Puducherry, India including all singleton, term pregnant women with vertex presentation, normal AFI and BMI &amp;#60;35 kg/m who delivered within the next 48 hours of assessment. The agreement between the different methods of fetal weight estimation and actual birth weight were calculated using intraclass correlation coefficient. Bland and Altman plot was done to identify the intervals of agreements. A total of 400 term antenatal women with age range of 17 to 44 years participated in the study. Intraclass correlation coefficient for Johnson’s formula was 0.816, Dare’s formula was 0.672 and Hadlock’s formula was 0.912. All the three methods had statistically significant correlation with the actual birth weight. Ultrasound estimation of fetal weight is the best out of the three methods and it correlated well with the actual birth weight. Johnson’s formula also gave results close to actual birth weight. With a correlation coefficient comparable to that of ultrasound estimation, Johnson’s formula can be used in low resource settings where ultrasound facilities are not available.

Comparing Fetal Ultrasound Biometric Measurements to Neonatal Anthropometry at the Extremes of Birth Weight.

Error in birthweight prediction by sonographic estimated fetal weight (EFW) has clinical implications, such as avoidable cesarean or misclassification of fetal risk in labor. We aimed to evaluate optimal timing of ultrasound and which fetal measurements contribute to error in fetal ultrasound estimations of birth size at the extremes of birthweight. We compared differences in head circumference (HC), abdominal circumference (AC), femur length, and EFW between ultrasound and corresponding birth measurements within 14 (n = 1,290) and 7 (n = 617) days of birth for small- (SGA, <10th percentile), appropriate- (AGA, 10th-90th), and large-for-gestational age (LGA, >90th) newborns. Average differences between EFW and birthweight for SGA neonates were: -40.2 g (confidence interval [CI]: -82.1, 1.6) at 14 days versus 13.6 g (CI: -52.4, 79.7) at 7 days; for AGA, -122.4 g (-139.6, -105.1) at 14 days versus -27.2 g (-50.4, -4.0) at 7 days; and for LGA, -242.8 g (-306.5, -179.1) at 14 days versus -72.1 g (-152.0, 7.9) at 7 days. Differences between fetal and neonatal HC were larger at 14 versus 7 days, and similar to patterns for EFW and birthweight, differences were the largest for LGA at both intervals. In contrast, differences between fetal and neonatal AC were larger at 7 versus 14 days, suggesting larger error in AC estimation closer to birth. Using a standardized ultrasound protocol, SGA neonates had ultrasound measurements closer to actual birth measurements compared with AGA or LGA neonates. LGA neonates had the largest differences between fetal and neonatal size, with measurements 14 days from delivery showing 3- to 4-fold greater differences from birthweight. Differences in EFW and birthweight may not be explained by a single fetal measurement; whether estimation may be improved by incorporation of other knowable factors should be evaluated in future research. · Ultrasound measurements may be inadequate to predict neonatal size at birth.. · Birthweight estimation error is higher for neonates >90th percentile.. · There is higher error in AC closer to birth..

Accuracy of antenatal ultrasound in predicting large-for-gestational-age babies: population-based cohort study

Pregnancies with large for gestational age fetuses are at increased risk of adverse maternal and neonatal outcomes. There is uncertainty about how to manage birth in such pregnancies. Current guidelines recommend a discussion with women of the pros and cons of options including expectant management, induction of labour and caesarean birth. For women to be able to make an informed decision about birth, antenatal detection of large for gestational age is essential. To investigate the ability of antenatal ultrasound scans to predict large for gestational age at birth. In this retrospective cohort study, we analysed data from a routinely collected database from the West Midlands, United Kingdom. We included pregnancies that had an antenatal ultrasound estimated fetal weight between 35+0 and 38+0 weeks gestation for any indication, as well as a subgroup where the reason for scan was that the fetus was suspected to be big. Large for gestational age was defined as >90th customized GROW centile, for estimated fetal weight as well as for neonatal weight. We also tested performance of an uncustomized standard, with Hadlock fetal weight >90th centile and neonatal weight >4kg. We calculated diagnostic characteristics for the whole population as well as groups with different maternal body mass indices. The study cohort consisted of 26,527 pregnancies which on average had a scan at 256 days gestation and delivered 20 days later at a median of 276 days (interquartile range 15). In total 2241 (8.4%) of neonates were large for gestational age by customized centiles, of which 1459 (65.1%) had a scan estimated fetal weight >90th centile, with a false positive rate of 8.6% and a positive predictive value of 41.0%. In the subgroup of 912 (3.4%) pregnancies scanned for a suspected large fetus, 293 (32.1%) babies were large for gestational age at birth, giving a positive predictive value of 50.3%, with sensitivity of 77.1% and false positive rate 36.0%. When comparing subgroups from low (<18.5kg/m2) to high body mass index (>30kg/m2), sensitivity increased from 55.6 to 67.8%, false positive rate from 5.2 to 11.5% and positive predictive value from 32.1 to 42.3%. A total of 2585 (9.7%) babies were macrosomic (birthweight >4kg), and of these 1058 (40.9%) were large for gestational age (>90th centile) antenatally by Hadlock's growth standard, with a false positive rate of 4.9% and a positive predictive value 41.0%. Analysis within subgroups showed better performance by customized compared to uncustomized standards for low body mass index (<18.5; diagnostic odds ratio 23.0 vs 6.4) and high body mass index (>30; diagnostic odds ration 16.2 vs 8.8). Late third trimester ultrasound estimation of fetal weight for any indication has good ability to identify and predict large for gestational age at birth, and improves with the use of a customised standard. Detection rate is better when ultrasound is performed for a suspected large fetus, however at the risk of higher false positive diagnosis. Our results provide information for women and clinicians to aid antenatal decision making about birth of a fetus suspected of being large for gestational age.

Effects of Size Polydispersity and Dense Media on Quantitative Ultrasound Estimates.

Quantitative ultrasound (QUS) techniques based on the backscatter coefficient (BSC) aim to characterize the scattering properties of biological tissues. A scattering model is fit to the measured BSC, and the fitted QUS parameters can provide local tissue microstructure, namely, scatterer size and acoustic concentration. However, these techniques may fail to provide a correct description of tissue microstructure when the medium is polydisperse and/or dense. The objective of this study is to investigate the effects of scatterer size polydispersity in sparse or dense media on the QUS estimates. Four scattering models (i.e., the monodisperse and polydisperse sparse models, and the monodisperse and polydisperse concentrated models based on the structure factor) are compared to assess their accuracy and reliability in quantifying the QUS estimates. Simulations are conducted with different scatterer size distributions for sparse, moderately dense, and dense media (volume fractions of 1%, 20%, and 73%, respectively). The QUS parameters are estimated by using model-based inverse methods at different center frequencies between 8 and 50 MHz. Experimental data are also analyzed using colon adenocarcinoma HT29 cell pellet biophantoms to further validate the results obtained from simulations at the volume fraction of 73%. Our findings reveal that the choice of scattering model has a significant impact on the accuracy of QUS estimates. For sufficiently high frequencies and dense media, the polydisperse concentrated model outperforms the other models and enables more accurate quantification. Furthermore, our results contribute to advancing our understanding of the complexities associated with scatterer size polydispersity and dense media in spectral-based QUS techniques.

DETERMINANTS AND ASSOCIATIONS OF COMMON CAROTID INTIMA-MEDIA ROUGHNESS IN PATIENTS WITH HYPERTENSION AND TYPE 2 DIABETES

Objective: Carotid atherosclerosis, including increased intima-media thickness (IMT) and plaque, is associated with increased cardiovascular (CV) risk. The role of the irregularity of the carotid intima-media surface in terms of total CV risk has been insufficiently investigated. This study investigated determinants and associations of common carotid intima-media roughness in patients with type 2 diabetes and hypertension. Design and method: Adults with type-2 diabetes and hypertension were evaluated with (i) 24h ambulatory blood pressure (ABP) monitoring (20 min intervals, Microlife WatchBPO3), (ii) carotid ultrasonography for the calculation of the common carotid IMT (use of automated software that allows the calculation of the average value of multiple measurements), carotid plaque score (CPS), and standard deviation (SD) of the common carotid intima-media (derived for the multiple measurements performed for the calculation of the IMT), and (iii) ultrasound estimation of left ventricular mass index (LVMI). Results: Ninety-five individuals were analyzed [age 66.3±8.9 years, 61 men, body mass index (BMI) 30.8±4.8 kg/m2, HbA1c 6.6±0.8%, 24-hour ABP (systolic/diastolic) 123±13/69.4±7.3 mmHg, IMT 0.83±0.16 mm, SD IMT 0.07±0.03 mm, CPS 5.5±4.8 mm]. SD IMT was correlated with IMT (r=0.49, p&lt;0.001), nighttime systolic ABP (r=0.21, p&lt;0.05), 24h weighted SD of systolic ABP (r=0.26, p&lt;0.05), CPS (r=0.30, p&lt;0.01) and LVMI (r=0.39, p&lt;0.001). In stepwise multivariable regression analysis with age, nighttime systolic ABP, 24h weighted SD of systolic ABP, total number of IMT measurements and IMT as independent variables, the SD IMT was determined by IMT (β=0.08, p&lt;0.001) and 24h weighted SD of systolic ABP (β=0.003, p&lt;0.05). Conclusions: These preliminary data suggest that in patients with type-2 diabetes and hypertension, carotid intima-media roughness is determined by IMT and the variability of 24h systolic ABP, and is associated with the severity of carotid atherosclerosis and left ventricular hypertrophy.

Utilité de la mesure échographique du segment utérin inférieur avant accouchement parmi les femmes ayant un antécédent de césarienne : revue de la littérature

Identifying women with a history of cesarean delivery and at real risk for uterine rupture is an important aim in obstetric care. It is with this objective that different authors have evaluated the interest of ultrasound for predicting the risk of a cesarean scar defect by measuring the thickness of the lower uterine segment. The literature is sparse and subject to numerous biases because they are mainly prospective cohort studies with small numbers. However, the results are concordant: Ultrasound measurements of lower uterine segment thickness are strongly correlated with the operative findings observed during cesarean delivery. Moreover, the thinner the lower uterine segment on ultrasound, the higher the likelihood of a uterine defect. Two randomized trials have recently been published. The PRISMA cluster randomized controlled trial evaluated a multifaceted intervention including an ultrasound estimation of the risk of uterine rupture by ultrasound measurement of the lower uterine segment thickness and aimed at helping women in their choice of mode of delivery after a previous cesarean delivery. This multifaceted intervention resulted in a significant reduction in the rates of major perinatal and maternal morbidity, without any increase in the rate of cesarean delivery or uterine rupture. However, due to its design, it is impossible to specifically specify the benefit of lower uterine segment measurement in reducing major maternal and perinatal morbidity since the trial combined several interventions. The LUSTrial randomized controlled trial evaluated the impact on maternal-fetal morbidity and mortality of proposing a mode of delivery based on ultrasound measurement of the lower uterine segment thickness compared to usual care among women with a history of cesarean delivery. Ultrasound measurement of lower uterine segment thickness was not associated with a statistically significant reduction in maternal-fetal morbidity and mortality compared to usual care. In this literature review, we will mainly detail and analyze the results of this trial.

Transcranial ultrasound estimation of viscoelasticity and fluidity in brain tumors aided by transcranial shear waves

Cerebral diseases, such as brain tumors, are intricately linked to the mechanical properties of brain tissues. Estimating the mechanical properties of brain tumors using transcranial ultrasound is a promising approach. However, the complexity of cranial features introduces challenges, such as ultrasound attenuation and interference from multidirectional transcranial shear waves induced by impact vibrations. To address these issues, this study proposes a transcranial ultrasound estimation method assisted by transcranial shear vibrations. Transcranial vibrations apply shear forces on the parietal bone, inducing unidirectional transcranial shear waves within brain tissue, as validated through simulations. Shear waves at different frequencies were captured via transcranial ultrasound, which were used to assess the viscoelasticity and fluidity of brain tumors. Transcranial experimental validations were conducted in 3D-printed models with tumor phantoms and ex vivo animal tumors. Vibration safety assessments were also performed. The results demonstrate that transcranial ultrasound can detect micron displacements induced by transcranial shear waves. In phantom and ex vivo animal experiments, speed distribution maps were employed to determine the size and location of one or two tumors enclosed in the skull model. The results revealed that the proposed approach could detect tumors with a minimum diameter of 0.8 cm and an inter-tumor distance of 0.8 cm. Notably, significant differences in viscoelasticity and fluidity between normal brain tissue and brain tumors were found (p<0.001). The maximum assessment errors for the elasticity, viscosity, and fluidity using transcranial ultrasound were 11.90%, 4.82%, and 0.73%, respectively, indicating that fluidity was more robust than viscoelasticity. The maximum accelerations of the skull were only 3.21 ms−2.

Fractional anisotropy within zone of destruction, tremor evaluation and MRI manifestation follow up after focused ultrasound thalamotomy for patients with Parkinson’s disease

Purpose. Assessment of MRI manifestation including fractional anisotropy within nucleus of destruction after focused ultrasound thalamotomy and estimation of its correlation with tremor severity.Material and methods. 7 patients with clinically approved Parkinson's disease were included. MRI examinations of the brain were performed before FUS-thalamotomy, within 3 hours, after 24 hours, after 3 and 6 months after the operation. The study protocol included routine MR sequences; fractional anisotropy maps were generated. Before surgery, after a day, 3 and 6 months, the severity of tremor was assessed by the CRST scale; CRST values correlation with the values of fractional anisotropy, as well as the correlation of the coordinates of the destruction focus with the residual therapeutic effect of the operation was estimated using a linear regression model.Results. The general patterns of the MRI manifestation were revealed: the appearance after the operation of the nucleus of destruction with the accumulation of paramagnetic substances in the structure and perifocal edema. The severity of the MRI-changes reached a maximum one day after the operation, regressed and were practically not visualized after 3 and 6 months. There was a high correlation between the volumes of the nucleus of destruction and perifocal edema, no correlation between the severity of tremor and the values of fractional anisotropy in the nucleus of destruction, a weak correlation between the localization of the nucleus of destruction and the value of the residual therapeutic effect of FUS-thalamotomy 6 months after surgery.Conclusions. The MRI manifestation during 6 months after FUS-thalamotomy had a similar character in all patients, reached a maximum severity one day after the operation and had gradual regression. Fractional anisotropy values did not correlate with tremor severity. For a prolonged therapeutic effect the contribution of the localization of the focus along the sagittal axis is possible.

Investigating the relationship between quantitative-based ultrasound and MRI estimations of rotator cuff fatty infiltration.

Fatty infiltration (FI) of the rotator cuff has important clinical implications. Quantitatively estimating FI using ultrasound (US) has considerable benefits for assessing FI in a non-invasive, accessible manner. This research investigated whether FI of the supraspinatus (SS) and infraspinatus (IS), estimated using US was related to intramuscular fat fractions measured from magnetic resonance images (MRI). Data from 12 healthy young adult participants were used for analysis. US images of the SS and IS were captured using multiple transducer placement techniques from which echogenicity of the muscle region was quantified. Shoulder MRI were captured from which SS and IS were manually segmented and intramuscular fat fractions calculated. Six upper limb strength exertions were performed, resisted by a hand dynamometer. IS and SS echogenicity explained a significant amount of variance in MRI fat fractions for certain body positions and transducer techniques. Echogenicity agreement was higher for IS than SS. Significant relationships were identified between strength exertions and both echogenicity and MRI muscle volume, but not MRI fat fraction. This research provides preliminary evidence showing that quantitative-based US methods can be used to estimate MRI calculated fat fractions for the rotator cuff.

A Novel Poroelastography Method for High-quality Estimation of Lateral Strain, Solid Stress and Fluid Pressure In Vivo.

Assessment of mechanical and transport properties of tissues using ultrasound elasticity imaging requires accurate estimations of the spatiotemporal distribution of volumetric strain. Due to physical constraints such as pitch limitation and the lack of phase information in the lateral direction, the quality of lateral strain estimation is typically significantly lower than the quality of axial strain estimation. In this paper, a novel lateral strain estimation technique based on the physics of compressible porous media is developed, tested and validated. This technique is referred to as "Poroelastography-based Ultrasound Lateral Strain Estimation" (PULSE). PULSE differs from previously proposed lateral strain estimators as it uses the underlying physics of internal fluid flow within a local region of the tissue as theoretical foundation. PULSE establishes a relation between spatiotemporal changes in the axial strains and corresponding spatiotemporal changes in the lateral strains, effectively allowing assessment of lateral strains with comparable quality of axial strain estimators. We demonstrate that PULSE can also be used to accurately track compression-induced solid stresses and fluid pressure in cancers using ultrasound poroelastography (USPE). In this study, we report the theoretical formulation for PULSE and validation using finite element (FE) and ultrasound simulations. PULSE-generated results exhibit less than 5% percentage relative error (PRE) and greater than 90% structural similarity index (SSIM) compared to ground truth simulations. Experimental results are included to qualitatively assess the performance of PULSE in vivo. The proposed method can be used to overcome the inherent limitations of non-axial strain imaging and improve clinical translatability of USPE.