Central Slices Research Articles

Deep neural network based CEST and AREX processing: Application in imaging a model of Alzheimer's disease at3T.

To optimize and apply deep neural network based CEST (deepCEST) and apparent exchange dependent-relaxation (deepAREX) for imaging the mouse brain with Alzheimer's disease (AD) at 3T MRI. CEST and T1 data of central and anterior brain slices of 10 AD mice and 10 age-matched wild type (WT) mice were acquired at a 3T animal MRI scanner. The networks of deepCEST/deepAREX were optimized and trained on the WT data. The CEST/AREX contrasts of AD and WT mice predicted by the networks were analyzed and further validated by immunohistochemistry. After optimization and training on CEST data of WT mice, deepCEST/deepAREX could rapidly (~1 s) generate precise CEST and AREX results for unseen CEST data of AD mice, indicating the accuracy and generalization of the networks. Significant lower amide weighted (3.5 ppm) signal related to amyloid β-peptide (Aβ) plaque depositions, which was validated by immunohistochemistry results, was detected in both central and anterior brain slices of AD mice compared to WT mice. Decreased magnetization transfer (MT) signal was also found in AD mice especially in the anterior slice. DeepCEST/deepAREX could rapidly generate accurate CEST/AREX contrasts in animal study. The well-optimized deepCEST/deepAREX have potential for AD differentiation at 3T MRI.

P57.04 Predicting Treatment Response to 1st- line Pembrolizumab in Advanced Non-Small Cell Lung Cancer (NSCLC) Patients with High PDL1 Expression

Combination of pembrolizumab and chemotherapy has shown improved survival in advanced NSCLC compared to chemotherapy alone. However, the overall response rate has only increased from 45% to 60% by adding chemotherapy to pembrolizumab alone for patients with high PDL1 expression (PD-L1 ≥50%). Currently no biomarker or clinicopathological features can be used to identify the subgroup with tumors PD-L1 ≥ 50% who would respond well to pembrolizumab alone in the 1st-line setting. We hypothesize a machine learning model trained on pre-treatment CT image radiomic features can be used as a digital biomarker to select the aforementioned subgroup, thereby reducing chemotherapy related toxicity and mitigating health care expenditure. We retrospectively identified stage III/IV NSCLC patients who received 1st-line single pembrolizumab at British Columbia Cancer (Vancouver, Canada), with PDL1 ≥50% and all had baseline staging CT within 6 weeks prior to starting immunotherapy and the 1st follow-up (FU) CT within 12 weeks after treatment initiation. The baseline and 1st follow-up CTs were reviewed by two oncological radiologists to identified the lung tumors on the baseline CT images and assess tumor response (i.e., partial response, PR vs progressive disease, PD) using RECIST 1.1 criteria. Utilizing an in-house CT Otsu based thresholding segmentation program and radiomic feature extraction pipeline, we identified potentially discriminating features from CT lung tumor images. We performed sequential forward feature selection to identify the 10 most highly classifying features from discrete shape, texture, and intensity radiomic features generated for 3 distinct tumor segmentation masks (lesion core, core with perimeter transition pixels, and the ring of parenchymal tissue surrounding the lesion). In this study, we leveraged an 8-Xfold validation Linear Discriminate Analysis (LDA), a simple machine learning method trained on these 10 features, to discriminate tumor response to 1st-line pembrolizumab as evaluated at FU CT scans. Sixty-eight patients were included (44% male, 73±6 yrs, 52ES/12CS/4NS; pack years: 43±18; ECOG range: 0-3). Twenty-eight showed response to the 1st-line pembrolizumab and forty had progressive disease. We identified eighty-four lung tumors in these patients which we extracted radiomic features from the five central slices, providing us with a pseudo-volumetric CT image training and test set (N=380). ROC analysis of the LDA model resulted in an accuracy of 79.4% [SN: 0.882, SP: 0.684] (AUC: 0.79) for our patient dataset. Given our class label imbalance, we performed precision-recall (PPV vs Sensitivity) analysis to identify sources of class bias (AUC vs No-skill AUC: 0.80 vs 0.59). Our data showed that a rudimentary and interpretable machine learning method can lead to appropriate treatment paths for advanced stage lung cancers. A combination of all mask features performed well on this task with a majority of the features selected being texture and intensity features from the core plus edge transitionary boundary pixels. Future analysis will be conducted using other machine learning methods to validate these findings, while keeping the LDA as the primary analysis method.

Association of Elbow Flexor MRI Fat Fraction With Loss of Hand-to-Mouth Movement in Patients With Duchenne Muscular Dystrophy.

Background and ObjectivesTo study the potential of quantitative MRI (qMRI) fat fraction (FF) as a biomarker in nonambulant patients with Duchenne muscular dystrophy (DMD), we assessed the additive predictive value of elbow flexor FF to age at loss of hand-to-mouth movement.MethodsNonambulant patients with DMD (age ≥8 years) were included. Four-point Dixon MRI scans of the right upper arm were performed at baseline and at the 12-, 18-, or 24-month follow-up. Elbow flexor FFs were determined from 5 central slices. Loss of hand-to-mouth movement was determined at study visits and by phone calls every 4 months. FFs were fitted to a sigmoidal curve by use of a mixed model with random slope to predict individual trajectories. The added predictive value of elbow flexor FF to age at loss of hand-to-mouth movement was calculated from a Cox model with the predicted FF as a time-varying covariate, yielding a hazard ratio.ResultsForty-eight MRIs of 20 patients with DMD were included. The hazard ratio of a percent-point increase in elbow flexor FF for the time to loss of hand-to-mouth movement was 1.12 (95% confidence interval 1.04–1.21; p = 0.002). This corresponded to a 3.13-fold increase in the instantaneous risk of loss of hand-to-mouth movement in patients with a 10–percent points higher elbow flexor FF at any age.DiscussionIn this prospective study, elbow flexor FF predicted loss of hand-to-mouth movement independently of age. qMRI-measured elbow flexor FF can be used as a surrogate endpoint or stratification tool for clinical trials in nonambulant patients with DMD.Classification of EvidenceThis study provides Class II evidence that qMRI FF of elbow flexor muscles in patients with DMD predicts loss of hand-to-mouth movement independently of age.

Femoro-Epiphyseal Acetabular Roof (FEAR) Index and Anterior Acetabular Coverage Correlate With Labral Length in Developmental Dysplasia of the Hip

The aim of this study was to evaluate the association between labral length and radiographic parameters of lateral and anterior acetabular coverage and the femoro-epiphyseal acetabular roof (FEAR) index in patients with developmental dysplasia of the hip (DDH). We retrospectively analyzed data from patients with DDH who visited our hip joint clinic for the first time due to hip symptoms. DDH presence was defined as a lateral center-edge angle (LCEA) of ≤25°. The labral lengths on the anterior and lateral sides were measured on central axial and central coronal slices of T1-weighted magnetic resonance imaging, respectively. The Pearson correlation coefficients (r) and simple linear regression analyses were performed to determine the association of the lateral and anterior labral lengths with the radiographic parameters, including the LCEA, acetabular roof obliquity, FEAR index, anterior wall index, and vertical center anterior angle. This study included 88 patients, with a mean age of 39.6 ± 11.8 years. There were 65 women and 23 men. The lateral and anterior labral lengths correlated with all parameters of dysplasia. Specifically, the lateral labral length had a strong positive correlation with the FEAR index (R= 0.65, P < .001). The anterior labral length had a strong negative correlation with the anterior wall index (R= -0.66, P < .001). The lateral labral length had a strong positive correlation with the FEAR index. Furthermore, the anterior labral length had a correlation with the anterior dysplasia. Level III, retrospective cross-sectional study.

Comparative observer effects in 2D and 3D localization tasks.

.Purpose: Three-dimensional “volumetric” imaging methods are now a common component of medical imaging across many imaging modalities. Relatively little is known about how human observers localize targets masked by noise and clutter as they scroll through a 3D image and how it compares to a similar task confined to a single 2D slice.Approach: Gaussian random textures were used to represent noisy volumetric medical images. Subjects were able to freely inspect the images, including scrolling through 3D images as part of their search process. A total of eight experimental conditions were evaluated (2D versus 3D images, large versus small targets, power-law versus white noise). We analyze performance in these experiments using task efficiency and the classification image technique.Results: In 3D tasks, median response times were roughly nine times longer than 2D, with larger relative differences for incorrect trials. The efficiency data show a dissociation in which subjects perform with higher statistical efficiency in 2D tasks for large targets and higher efficiency in 3D tasks with small targets. The classification images suggest that a critical mechanism behind this dissociation is an inability to integrate across multiple slices to form a 3D localization response. The central slices of 3D classification images are remarkably similar to the corresponding 2D classification images.Conclusions: 2D and 3D tasks show similar weighting patterns between 2D images and the central slice of 3D images. There is relatively little weighting across slices in the 3D tasks, leading to lower task efficiency with respect to the ideal observer.

Novel Methodology for Measuring Regional Myocardial Efficiency.

Our approach differs from the usual global measure of cardiac efficiency by using PET/MRI to measure efficiency of small pieces of cardiac tissue whose limiting size is equal to the spatial resolution of the PET scanner. We initiated a dynamic cardiac PET study immediately prior to the injection of 15.1 mCi of 11C-acetate acquiring data for 25 minutes while simultaneously acquiring MRI cine data. 1) A 3D finite element (FE) biomechanical model of the imaged heart was constructed by utilizing nonrigid deformable image registration to alter the Dassault Systèmes FE Living Heart Model (LHM) to fit the geometry in the cardiac MRI cine data. The patient specific FE cardiac model with estimates of stress, strain, and work was transformed into PET/MRI format. 2) A 1-tissue compartment model was used to calculate wash-in (K1) and the linear portion of the decay in the PET 11C-acetate time activity curve (TAC) was used to calculate the wash-out k2(mono) rate constant. K1 was used to calculate blood flow and k2(mono) was used to calculate myocardial volume oxygen consumption ( MVO2 ). 3) Estimates of stress and strain were used to calculate Myocardial Equivalent Minute Work ( MEMW ) and Cardiac Efficiency = MEMW/MVO2 was then calculated for 17 tissue segments of the left ventricle. The global MBF was 0.96 ± 0.15 ml/min/gm and MVO2 ranged from 8 to 17 ml/100gm/min. Six central slices of the MRI cine data provided a range of MEMW of 0.1 to 0.4 joules/gm/min and a range of Cardiac Efficiency of 6 to 18%.

Diffraction-Ray Optics of Femtosecond Laser Pulses Propagating in Air Under the Influence of the Normal Group Velocity Dispersion

Results of theoretical study of the femtosecond Ti:Sa laser pulse propagation in air under the influence of the normal group velocity dispersion are presented. The use of the diffraction-ray tube method for an analysis of numerical solutions of the nonlinear Schrodinger equation in chromatic dispersion medium with the Kerr and plasma nonlinearity makes it possible to determine the main regularities of the femtosecond laser pulse selffocusing and filamentation in air for various pulse durations, initial beam radii, and peak powers. It is shown that under the influence of the group velocity dispersion, the filamentation terminates with an increase in the initial radius of the laser beam even at high values of supercritical powers. With an increase in the dispersion distortions of the pulse, the radius of the energetically replenishing diffraction-ray tube, the angular divergence of the post-filamentation light channel, and the nonlinear focus coordinate normalized to the Rayleigh length increase in the central time slices of the laser pulse and its integral pattern.

Clinical implementation of accelerated T2 mapping: Quantitative magnetic resonance imaging as a biomarker for annular tear and lumbar disc herniation

ObjectivesThis study evaluates GRAPPATINI, an accelerated T2 mapping sequence combining undersampling and model-based reconstruction to facilitate the clinical implementation of T2 mapping of the lumbar intervertebral disc.MethodsFifty-eight individuals (26 females, 32 males, age 23.3 ± 8.0 years) were prospectively examined at 3 T. This cohort study consisted of 19 patients, 20 rowers, and 19 volunteers. GRAPPATINI was conducted with the same parameters as a conventional 2D multi-echo spin-echo (MESE) sequence in 02:27 min instead of 13:18 min. Additional T2 maps were calculated after discarding the first echo (T2-WO1ST) and only using even echoes (T2-EVEN). Segmentation was done on the four most central slices. The resulting T2 values were compared for all four measurements.ResultsT2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1ST of the nucleus pulposus of normal discs differed significantly from those of bulging discs or herniated discs (all p < 0.001). For the posterior annular region, only T2-GRAPPATINI showed a significant difference (p = 0.011) between normal and herniated discs. There was a significant difference between T2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1ST of discs with and without an annular tear for the nucleus pulposus (all p < 0.001). The nucleus pulposus’ T2 at different degeneration states showed significant differences between all group comparisons of Pfirrmann grades for T2-GRAPPATINI (p = 0.000–0.018), T2-MESE (p = 0.000–0.015), T2-EVEN (p = 0.000–0.019), and T2-WO1ST (p = 0.000–0.015).ConclusionsGRAPPATINI facilitates the use of T2 values as quantitative imaging biomarkers to detect disc pathologies such as degeneration, lumbar disc herniation, and annular tears while simultaneously shortening the acquisition time from 13:18 to 2:27 min.Key Points• T2-GRAPPATINI, T2-MESE, T2-EVEN, and T2-WO1STof the nucleus pulposus of normal discs differed significantly from those of discs with bulging or herniation (all p < 0.001).• The investigated T2mapping techniques differed significantly in discs with and without annular tearing (all p < 0.001).• The nucleus pulposus’ T2showed significant differences between different stages of degeneration in all group comparisons for T2-GRAPPATINI(p = 0.000–0.018), T2-MESE(p = 0.000–0.015), T2-EVEN(p = 0.000–0.019), and T2-WO1ST(p = 0.000–0.015).

Temperature dependence and temporal stability of stacked radiochromic sheets for three-dimensional dose verification.

Recently a novel radiochromic sheet dosimeter, termed as PRESAGE sheets, consisting of leuco crystal violet dye and radical initiator had been developed and characterized. This study examines the dosimeter's temporal stability and storage temperature dependence postirradiation, and its applicability for dose verification in three dimensions (3D) as a stack dosimeter. PRESAGE sheets were irradiated using 6MV photons at a dose range of 0-20Gy with the change in optical density measured using a flatbed scanner. Following their irradiation, PRESAGE sheets were stored in different temperature environments (-18 °C, 4 °C, and 22 °C) and scanned at different time points, ranging from 1 to 168h postirradiation, to track changes in measured signal and linearity of dose response. Multiple PRESAGE sheets were bound together to create a 12×13×8.7cm3 film stack, with EBT3 film inserted between the sheets in the central region of the stack, that was treated using a clinical VMAT plan. Based on the results from the time and storage temperature study, two-dimensional (2D) relative dose distribution measurements in PRESAGE were acquired promptly following irradiation at selected planes in the coronal, sagittal, and axial orientation of the film stack and compared to the treatment planning system calculations in their respective axes. Dose distribution measurements on the coronal axis of the stack dosimeter were also independently verified using EBT3 film. The dose response was observed to be linear (R2 >0.995) with sheets stored in colder temperatures retaining their signal and dose response sensitivity for extended periods postirradiation. Sheets stored in 22 °C environment should be measured within an hour postirradiation. Sheets stored in a 4 °C and -18 °C environment can be scanned up to 20- and 72 h postirradiation, respectively, while preserving the integrity of their dose response sensitivity and linearity of dose response within a mean absolute percent error of 2.0%. For instance, at 20 h postirradiation the dose response sensitivity for sheets stored in a -18 °C, 4 °C, and 22 °C temperature environment was measured to be 97%, 91%, and 77% of their original values measured within an hour postirradiation, respectively. The 2D gamma pass rate for central slices exceed 95% for PRESAGE film stack compared with treatment planning system on selected planes in the axial, coronal, and sagittal orientation and EBT3 film in the coronal orientation using a 2D gamma index of 2%/2mm. The gamma pass rate in comparing the calculated dose distribution with the measured dose distribution from PRESAGE-LCV was observed to decrease in sheets scanned at later elapsed times postirradiation. In one example, the gamma pass rate for 2%/2mm criteria in the coronal plane was observed to decrease from 97.7% pass rate when scanned within an hour postirradiation to 92.1% pass rate when scanned at 20 h postirradiation under room temperature conditions. This is the first study to demonstrate that the temporal stability of PRESAGE sheets can be enhanced through its storage in colder temperature environments postirradiation and that sheets as a film stack dosimeter hold promise for precise relative dose distribution measurements in 3D where advanced optical CT is unavailable.

MUSCLE IMAGING – MRI: P.166 Muscle MRI as biomarker of disease progression in Becker muscular dystrophy: a 2 year follow-up study

Becker muscular dystrophy (BMD) is hallmarked by clinical variability and slow but unpredictable deterioration. Biomarkers are needed that correlate with function and reliably detect disease progression within the time of a trial. We explored the feasibility of quantitative muscle MRI (qMRI) in BMD as such a biomarker. In this 2 year follow up study, 24 BMD patients were included at baseline. 3-point Dixon 3T MRI scans (23 slices of 1 cm, 0.5cm gap) were acquired of the thigh and lower leg (LL). Weighted average fat fractions (wFF) of 12 thigh and 7 LL muscles and 5 muscle groups were determined over three central slices (3S) using landmarks, and over the whole muscle (WM). Functional assessment included 6-minute walk test (6MWT), North Star Ambulatory Assessment (NSAA) and maximal voluntary contraction of knee extension and flexion. Wilcoxon signed rank test and Spearman's correlation were used for statistics (significance p<0.05). Nineteen patients (median age 40.4 years, range 18.8-66.3) completed baseline and follow-up assessments. Baseline vastus lateralis and quadriceps wFF 3S and MW correlated highly to all functional parameters (rho>=0.720). At 2 years, wFF of 3S and WM increased in 11 of 19 muscles. The median FF increase was similar in 3S and WM for all muscles. High standardized response means (SRMs; >=0.8) were obtained in the thigh for all individual quadriceps WMs (SRMs 0.89-1.00) but not for 3S (SRMs 0.67-0.79). In the LL, only the SRM of gastrocnemius medialis WM was high (0.95). In muscle groups, highest SRMs were obtained for both 3S and WM in quadriceps and whole thigh (SRMs 0.91-1.21). Among function tests, only NSAA (-3.0, SD 4.0) and 10-meter run test velocity (-0.29m/s, SD 0.48) decreased, resulting in SRMs of -0.75 and -0.62. Knee flexion strength decreased by 2.1kg (SD 2.64, SRM -0.78). Due to high correlations with function and high SRMs, we propose qMRI as feasible biomarker in BMD. Composite WM thigh group SRMs were highest, potentially allowing for smaller sample sizes when used as outcome measure in trials.

An increasing Cr recovery from soil with catholyte-enhanced electrokinetic remediation: Effects on voltage redistribution throughout soil sections

The evolution of potential gradient across different soil sections that were responsible for divergence of Cr migration in electrokinetic (EK) remediation need further investigate. Here, the redistribution of Cr and voltage was conducted out under four kinds of catholytes applying a constant potential. The results showed that the total removal efficiency of dissolved Cr from soil matrix achieved 51.7% with humic acid (HA) catholyte, compared to 40.4, 36.5 and 31.9% with KCl, citric aicd (CA) and H2O catholytes, respectively. The voltage drops on soil cells were enhanced with assisted catholytes, in which facilitating the migration capacity of Cr out of soil in a faster way. The voltage shifted to cathode electrode with a significant value of above 17 V over 12 d due to polarization in EK-H2O, which may become the limiting factor for driving the Cr migration. The voltage located in the last two soil slices that controlled by electric conductivity of pore water made a large proportion of 4.3–5.2 V (1.08–1.4 V cm−1) in EK-CA, which was consistent with the highest Cr removal efficiency of 64.3–85.6%. Whilst the voltage concentrated in the first soil slice and central slices related to water holding capacity reached 3.3–5.6 V (0.83–1.40 V cm−1) in EK-HA, contributing to a remarkably increasing Cr removal efficiency of 49.3–58.7%. In addition, HA can restrain the transformation and migration of Ca and S ions. Furthermore, higher migration potential for Cr indicated the voltage were efficiently consumed on Cr depletion in EK-HA. These suggested that HA was optional catholyte for site with the utmost Cr recovery and lower energy loss.

Accelerated T2 Mapping of the Lumbar Intervertebral Disc: Highly Undersampled K-Space Data for Robust T2 Relaxation Time Measurement in Clinically Feasible Acquisition Times.

Fifty-eight individuals (26 female; mean age, 23.3 ± 8.1 years) were prospectively studied at 3 T. GRAPPATINI was conducted with the same parameters as the 2D-MESE while shortening the acquisition time from 13:18 to 2:27 minutes. The setup was also validated in a phantom experiment using a 6.48-hour-long single echo-spin echo sequence as reference. The IVDs were manually segmented on 4 central slices. The median nucleus pulposus showed a strong Pearson correlation coefficient between T2GRAPPATINI and T2MESE (rp = 0.919; P < 0.001). There was also a significant correlation for the ventral (rp = 0.241; P < 0.001) and posterior (rp = 0.418; P < 0.001) annular regions.In the single spin-echo phantom experiment, the most accurate T2 estimation was achieved using T2GRAPPATINI with a median absolute deviation of 15.3 milliseconds as compared with T2MESE with 26.5 milliseconds. GRAPPATINI facilitates precise T2 mapping at 3 T in accordance with clinical standards and reference methods using the same parameters while shortening acquisition times from 13:18 to 2:27 minutes with the same parameters.

A transmit-receive array for brain imaging with a high-performance gradient insert.

The aim of this work was to provide parallel imaging capability for the human head in a gradient insert of 33-cm inner diameter within the related constraints of space, encoding ambiguity, and eddy current immunity. Eddy current behavior of the 8-channel transmit-receive array coil was investigated via heating and field deviation measurements. RF performance was evaluated using S-parameters, noise statistics, B1 maps, and g-factor maps. In vivo images of a human head and knee were acquired with Cartesian readout and TE below 0.45ms. Under intense gradient use, the shield was heated up to 55°C and other coil structures to 40°C. After standard preemphasis calibration, eddy current-related field distortions caused by the developed RF coil were smaller than for a commercial receive-only coil. In the ambiguous regions of the gradient, is 20dB lower than in the center of the FOV. Coupling between elements is below -15dB, and noise correlation is less than 0.31 when the coil is loaded with a head. Power efficiency was 0.52 ± 0.02μT/√W, and the SD of the flip angle was below 10% in central slices of the brain. 2D, up to fourfold acceleration causes less than 30% noise amplification. The RF coil can be used during full gradient performance. Based on the described features, the presented coil enables parallel imaging in the high-performance gradient insert.

The optimal cutoff value for levator-urethra gap measurements using tomographic ultrasound imaging in avulsion diagnosis is population specific.

The levator-urethra gap (LUG), the distance between the urethral lumen center and levator insertion on the inferior pubic rami, can be used for diagnosing levator avulsion, with a previously suggested cutoff of LUG ≥2.5 cm. The aim of this study is to determine an optimal cutoff value for LUG measurements in a high-risk patient population. Women followed prospectively after sustaining obstetric anal sphincter injury underwent an interview pelvic examination questionnaires and four-dimensional-transperineal ultrasound examination. Levator avulsion was diagnosed on contraction using tomographic ultrasound imaging. Ultrasound datasets were analyzed offline at a later time blinded to previous data. LUG was measured on each side of the three central slices, yielding six measurements and the highest available value was obtained on each side. Different cutoffs were evaluated using receiver-operating characteristics (ROC) curve analysis and Youden's test. The cutoff was validated against symptoms and signs, and sonographic findings using logistic regression analysis. A total of 618 complete datasets were available for analysis, median age 29 years, median body mass index of 23.4 kg/m2 , parity 1, and 26.4% instrumental deliveries. Youden's test and ROC curve analysis gave the best area under the curve of 0.869 for a cutoff of 2.305 (95% confidence interval, 0.839-0.9). Women diagnosed with avulsion based on this cutoff were more symptomatic, whereas using larger cutoffs missed more avulsion defects. LUG measurement is useful but should be individualized to the population studied, in our case, in a high-risk population, 2.305 cm was the optimal cutoff. Using larger cutoffs may be more specific but is likely to miss more cases.

Malmström vacuum or Kielland forceps: which causes more damage to pelvic floor?

To determine whether differences exist in the rate of levator ani muscle (LAM) avulsion between women who had undergone either Malmström vacuum delivery (MVD) or Kielland forceps delivery (KFD), allowing for potential confounding factors. This was a prospective observational study of nulliparous women undergoing instrumental delivery using Malmström vacuum extractor or Kielland forceps, at two hospital centers in Spain. Fetal head position (anterior, posterior or transverse) and fetal head station (low or mid) were assessed by ultrasound and digital examination, respectively. Avulsion was defined on tomographic ultrasound imaging as an abnormal insertion of the LAM in the three central slices from the plane of minimal hiatal dimensions. In total, 414 patients were included in the study (212 MVD and 202 KFD). We observed a higher rate of LAM avulsion in the KFD group (KFD 49.5% vs MVD 32.5%; P = 0.001). When the results were evaluated according to fetal head position and station, we observed no differences in LAM avulsion. The crude odds ratio (OR) for the difference in avulsion between women in the KFD and MVD groups was 2.03 (95% CI, 1.36-3.03). However, when adjusted for duration of second stage of labor, fetal head circumference and fetal head station, the OR was no longer statistically significant (OR, 2.14 (95% CI, 0.95-4.85); P = 0.068). When potential confounding factors are taken into account, the rate of LAM avulsion does not differ between women according to whether they have undergone KFD or MVD. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Evaluation of the Fermentation Dynamics of Commercial Baker’s Yeast in Presence of Pistachio Powder to Produce Lysine-Enriched Breads

The present work was carried out to evaluate the microbiological, physicochemical, and sensory characteristics of fortified pistachio breads. Pistachio powder (5% w/w) was added to flour or semolina and fermented by a commercial baker’s yeast (Saccharomyces cerevisiae). Pistachio powder did not influence the biological leavening of the doughs. The kinetics of pH and total titratable acidity (TTA) during dough fermentation showed that the leavening process occurred similarly for all trials. The concentration of yeasts increased during fermentation and reached levels of 108 CFU/g after 2 h. Pistachio powder decreased the height and softness of the final breads and increased cell density of the central slices. The amount of lysine after baking increased in pistachio breads and this effect was stronger for semolina rather than flour trials. Sensory evaluation indicated that fortified breads processed from semolina were those more appreciated by the judges. This work clearly indicated that the addition of pistachio powder in bread production represents a promising strategy to increase the availability of lysine in cereal-based fermented products.

Is levator trauma an independent risk factor for anal incontinence?

To determine the role of levator ani trauma in anal incontinence (AI), whilst controlling for anal sphincter injury. The records of 1273 patients who had attended a tertiary urogynaecology unit between 1st of January to 31st December 2016 were reviewed. AI was assessed using St Mark's score and visual analogue scale (VAS). Levator muscle and anal sphincter trauma were examined by translabial ultrasound using tomographic imaging, with archived data sets investigated blinded against all clinical data. A complete avulsion was diagnosed if at least three central tomographic slices showed an abnormal muscle insertion, rated separately for each side. A significant anal sphincter defect was diagnosed if at least four out of six slices showed a defect of ≥30°. Avulsion was associated with St Mark's score (P=0.005) and VAS bother of AI (P=0.022) both on univariate analysis and when controlling for external anal sphincter (EAS) trauma on translabial imaging, forceps, body mass index (BMI) and age (P=0.011 and P=0.04, respectively). AI expressed as a binary variable was significantly associated with avulsion on univariate analysis (P=0.011), although the association became nonsignificant after controlling for anal sphincter trauma, age, BMI and forceps delivery (P=0.084). In this retrospective observational study, we found a weak association between levator ani avulsion and measures of AI, which largely remained significant when controlling for anal sphincter trauma. However, given the large data set, any clinical effect of levator trauma on AI is likely to be minor.

Segmentation and Modelling of the Nuclear Envelope of HeLa Cells Imaged with Serial Block Face Scanning Electron Microscopy.

This paper describes an unsupervised algorithm, which segments the nuclear envelope of HeLa cells imaged by Serial Block Face Scanning Electron Microscopy. The algorithm exploits the variations of pixel intensity in different cellular regions by calculating edges, which are then used to generate superpixels. The superpixels are morphologically processed and those that correspond to the nuclear region are selected through the analysis of size, position, and correspondence with regions detected in neighbouring slices. The nuclear envelope is segmented from the nuclear region. The three-dimensional segmented nuclear envelope is then modelled against a spheroid to create a two-dimensional (2D) surface. The 2D surface summarises the complex 3D shape of the nuclear envelope and allows the extraction of metrics that may be relevant to characterise the nature of cells. The algorithm was developed and validated on a single cell and tested in six separate cells, each with 300 slices of 2000 × 2000 pixels. Ground truth was available for two of these cells, i.e., 600 hand-segmented slices. The accuracy of the algorithm was evaluated with two similarity metrics: Jaccard Similarity Index and Mean Hausdorff distance. Jaccard values of the first/second segmentation were 93%/90% for the whole cell, and 98%/94% between slices 75 and 225, as the central slices of the nucleus are more regular than those on the extremes. Mean Hausdorff distances were 9/17 pixels for the whole cells and 4/13 pixels for central slices. One slice was processed in approximately 8 s and a whole cell in 40 min. The algorithm outperformed active contours in both accuracy and time.

Utilization of an optimum low-pass filter during filtered back-projection in the reconstruction of single photon emission computed tomography images of small structures

Introduction:Low-pass filters eliminate noise, and accordingly improve the quality of filtered back-projection (FBP) in the reconstruction of single photon emission computed tomography (SPECT) images. This study aimed at selection of an optimum low-pass filter for FBP reconstruction of SPECT images of small structures. Material and Methods:Spheres A, B, and C (16 mm, 12 mm, and 11 mm in diameter, respectively) attached to capillary stems were filled with technetium-99m solution (activity concentration 300 kBq/mL). They were then mounted inside a Jaszczak Phantom forming a V-shaped structure. The phantom was then filled with distilled water. Two-dimensional (2D) projections were acquired on 128 128 pixels using a Siemens E-Cam dual-head gamma camera. The Parzen, Shepp-Logan, Low Pass Cosine filters (cut-off frequencies: 0.2-0.9), and Butterworth filter (order: 1-9; cut-off frequencies: 0.3-0.9) were employed during FBP reconstruction. The line command of ImageJ software was used to draw the point spread functions of acquired 2D transaxial central slices and for the measurement of their full-width at half-maximum (FWHM). Results:The FWHM of 2D central image slices of spheres A, B, and C reconstructed using a Butterworth filter measured 20, 20, and 10 pixels, respectively. In comparison, the reconstructed images using the Parzen, Low Pass Cosine, and Shepp-Logan filters measured to 27, 25 and, 22 pixels for sphere A, 24, 22, 20 pixels for B, and 22, 20, 18 pixels for C, respectively. Conclusion: The low-pass filters successfully suppressed noise during the FBP reconstruction of SPECT images of small structures. Accordingly, the Butterworth is a suitable choice.

Quantitative magnetization transfer imaging of the human locus coeruleus

The locus coeruleus (LC) is the major origin of norepinephrine in the central nervous system, and is subject to age-related and neurodegenerative changes, especially in disorders such as Parkinson's disease and Alzheimer's disease. Previous studies have shown that neuromelanin (NM)-sensitive MRI can be used to visualize the LC, and it is hypothesized that magnetization transfer (MT) effects are the primary source of LC contrast. The aim of this study was to characterize the MT effects in LC imaging by applying high spatial resolution quantitative MT (qMT) imaging to create parametric maps of the macromolecular content of the LC and surrounding tissues. Healthy volunteers (n = 26; sex = 17 F/9M; age = 41.0 ± 19.1 years) underwent brain MRI on a 3.0 T scanner. qMT data were acquired using a 3D MT-prepared spoiled gradient echo sequence. A traditional NM scan consisting of a T1-weighted turbo spin echo sequence with MT preparation was also acquired. The pool-size ratio (PSR) was estimated for each voxel using a single-point qMT approach. The LC was semi-automatically segmented on the MT-weighted images. The MT-weighted images provided higher contrast-ratio between the LC and surrounding pontine tegmentum (PT) (0.215 ± 0.031) than the reference images without MT-preparation (−0.005 ± 0.026) and the traditional NM images (0.138 ± 0.044). The PSR maps showed significant differences between the LC (0.090 ± 0.009) and PT (0.188 ± 0.025). The largest difference between the PSR values in the LC and PT was observed in the central slices, which also correspond to those with the highest contrast-ratio. These results highlight the role of MT in generating NM-related contrast in the LC, and should serve as a foundation for future studies aiming to quantify pathological changes in the LC and surrounding structures in vivo.