Asymmetry Ratio Research Articles

Amide proton transfer-weighted CEST MRI for radiotherapy target delineation of glioblastoma: a prospective pilot study

BackgroundExtensive glioblastoma infiltration justifies a 15-mm margin around the gross tumor volume (GTV) to define the radiotherapy clinical target volume (CTV). Amide proton transfer (APT)-weighted imaging could enable visualization of tumor infiltration, allowing more accurate GTV delineation. We quantified the impact of integrating APT-weighted imaging into GTV delineation of glioblastoma and compared two APT-weighted quantification methods—magnetization transfer ratio asymmetry (MTRasym) and Lorentzian difference (LD) analysis—for target delineation.MethodsNine glioblastoma patients underwent an extended imaging protocol prior to radiotherapy, yielding APT-weighted MTRasym and LD maps. From both maps, biological tumor volumes were generated (BTVMTRasym and BTVLD) and added to the conventional GTV to generate biological GTVs (GTVbio,MTRasym and GTVbio,LD). Wilcoxon signed-rank tests were performed for comparisons.ResultsThe GTVbio,MTRasym and GTVbio,LD were significantly larger than the conventional GTV (p ≤ 0.022), with a median volume increase of 9.3% and 2.1%, respectively. The GTVbio,MTRasym and GTVbio,LD were significantly smaller than the CTV (p = 0.004), with a median volume reduction of 72.1% and 70.9%, respectively. There was no significant volume difference between the BTVMTRasym and BTVLD (p = 0.074). In three patients, BTVMTRasym delineation was affected by elevated signals at the brain periphery due to residual motion artifacts; this elevation was absent on the APT-weighted LD maps.ConclusionLarger biological GTVs compared to the conventional GTV highlight the potential of APT-weighted imaging for radiotherapy target delineation of glioblastoma. APT-weighted LD mapping may be advantageous for target delineation as it may be more robust against motion artifacts.Relevance statementThe introduction of APT-weighted imaging may, ultimately, enhance visualization of tumor infiltration and eliminate the need for the substantial 15-mm safety margin for target delineation of glioblastoma. This could reduce the risk of radiation toxicity while still effectively irradiating the tumor.Trial registrationNCT05970757 (ClinicalTrials.gov).Key PointsIntegration of APT-weighted imaging into target delineation for radiotherapy is feasible.The integration of APT-weighted imaging yields larger GTVs in glioblastoma.APT-weighted LD mapping may be more robust against motion artifacts than APT-weighted MTRasym.Graphical

Bending of polymer films: a method for obtaining a compressive modulus of thin films.

Due to the advent of various foldable electric devices, it is becoming increasingly important to understand the bending properties of film materials. Bending of isotropic materials may be trivial if elastic deformation is small within a range of linear elasticity, which is often the case for bending. However, bending of polymer films, often used in recent foldable devices, may not be the case. Polymer films are frequently fabricated with stretching, which induces anisotropic orientation of molecular chains. In addition, there are many studies on bimodulus materials, which suggest the importance of the difference in tensile and compressive elastic moduli, i.e., the importance of elastic asymmetry, considering that bending involves compression and extension. In this study, we extended the standard linear elastic theory to include elastic anisotropy and elastic asymmetry and developed a method for obtaining compressive moduli of films, which cannot be obtained by a simple compression test because thin films under compression buckle at small strains. Our method is based on a bending test combined with a uniaxial tension test, which allows the measurement of Poisson's ratio in addition to Young's modulus, which are both anisotropic and asymmetric. To test our theory and method, we further performed experiments on biaxially stretched poly(ethylene terephthalate) (PET) films. As a result, we found non-negligible anisotropy in Poisson's ratio and non-negligible asymmetry (bimodulus) in tensile and compressive moduli. We further justify our framework by demonstrating a clear data collapse to show agreement between experiment and theory, clarifying limitations. Our results suggest the importance of elastic anisotropy and elastic asymmetry in bending of industrial films and give fundamental knowledge on this subject, which would be useful for applications. Such applications include the control of the position of the neutral plane and precise measurements of elastic moduli and Poisson's ratio, which are crucial, e.g., for the development of tough flexible electric devices and for the structural designs using compliant mechanisms.

Video head impulse gain is impaired in myotonic dystrophy types 1 and 2.

This study was undertaken to examine vestibulo-ocular reflex (VOR) characteristics in myotonic dystrophy type 1 (DM1) and type 2 (DM2) using video head impulse testing (vHIT). VOR gain, refixation saccade prevalence, first saccade amplitude, onset latency, peak velocity, and duration were compared in DM1, DM2, age-matched normal controls, and patients with peripheral and central vestibulopathies. Fifty percent of DM1 and 37.5% of DM2 patients demonstrated reduced VOR gain. Refixation saccade prevalence for horizontal canal (HC) and posterior canal (PC) was significantly higher in DM1 (101 ± 42%, 82 ± 47%) and DM2 (70 ± 45%, 61 ± 38%) compared to controls (40 ± 28% and 43 ± 33%, p < 0.05). The first saccade amplitudes and peak velocities were higher in HC and PC planes in DM1 and DM2 compared to controls (p < 0.05). HC slow phase eye velocity profiles in DM1 showed delayed peaks. The asymmetry ratio, which represents the percentage difference between the first and second halves of the slow phase eye velocity response, was therefore negative (-22.5 ± 17%, -2.3 ± 16%, and - 4.7 ± 8% in DM1, DM2, and controls). HC VOR gains were lower and gain asymmetry ratio was larger and negative in patients with DM1 with moderate to severe ptosis and a history of imbalance and falls compared to the remaining DM1 patients (p < 0.05). In peripheral vestibulopathies, saccade amplitude was larger, peak velocity was higher, and onset latency was shorter (p < 0.05) than in DM1. In central vestibulopathy (posterior circulation strokes), saccade peak velocity was higher, but amplitude and onset latency were not significantly different from DM1. VOR impairment is common in DM1 and DM2. In DM1, refixation saccade characteristics are closer to central than peripheral vestibulopathies. Delayed peaks in the vHIT eye velocity profile observed in patients with DM1 may reflect extraocular muscle weakness. VOR impairment and VOR asymmetry in DM1 are associated with imbalance and falls.

Assessing the Correlation Between Retinal Arteriolar Bifurcation Parameters and Coronary Atherosclerosis.

The aim of this study was to examine the relationship between the morphological parameters of retinal arteriolar bifurcations and coronary artery disease (CAD). In this cross-sectional observational study, fundus photography was conducted on 444 participants to capture retinal arteriolar bifurcations. A total of 731 fundus photographs yielded 9625 measurable bifurcations. Analyzed bifurcation parameters included the diameters of the parent vessel (d0), the larger branch (d1), and the smaller branch (d2), as well as the angles (θ1) and (θ2) representing the orientation of each branch in relation to the parent vessel, respectively. Additionally, theoretical optimal angles ( ) and ( ), calculated from the measured parameters, provided a benchmark for ideal bifurcation geometry. The study assessed the variation in these parameters across different levels of coronary atherosclerosis severity. After adjusting for anatomical characteristics including the asymmetry ratio, area ratio, and distance to the optic disc, we observed that patients with severe coronary artery stenosis had significant deviations from the theoretical optimal bifurcation angles, with a decrease in ( ) and an increase in ( ) compared to those with moderate stenosis. The findings suggest a clear alteration in retinal arteriolar bifurcation morphology among patients with severe CAD, which could potentially serve as an indicator of disease severity.

Reference ranges and test-retest reliability of subject visual horizontal from different head-tilt angles in young healthy adults

Objective:To establish the normal values of subjective visual horizontal（SVH） under different head tilt angles, analyze the test-retest reliability, and provide a normal value reference for the refined diagnosis and functional assessment of SVH in clinical vestibular disorders. Methods:Thirty-one healthy young people were selected to wear visual reality glasses to test SVH data in five different head tilt angles: upright head position 0°, head tilted 45°to the left（L45°）, head tilted 45° to the right（R45°）, head tilted 90° to the left（L90°）, and head tilted 90° to the right（R90°）, and were re-tested 2 weeks later. Results:①The normal values of SVH at 0°, L45°, R45°, L90°, and R90°were 0.30±1.32, 5.94±5.54, -11.44±5.32, -0.87±8.63, -2.70±8.02, respectively. ②The 95% confidence intervals of SVH at 0°, L45°, R45°, L90°, and R90° were: （-2.34,2.94）,（-5.14,17.02）,（-22.08,-0.80）,（-18.13,16.39）,（-18.74，13.34）, respectively. The ratio of asymmetry in the absolute value of bilateral 45° deviation was 26.4% and the ratio of asymmetry in the absolute value of bilateral 90° deviation was 1.3%. ③The intra-class correlation coefficient（ICC） for 0°, L45°, R45°, L90° and R90° was 0.625, 0.641, 0.564, 0.769, 0.656, respectively. Conclusion:SVH has good test-retest reliability and high clinical test stability and stability. The data on normal values of SVH at different head tilt angles established in this study can provide clinical references for the refined diagnosis and functional assessment of vestibular system disorders.

Intraocular Pressure and Cup-to-Disc Ratio Asymmetry in Diagnosing Iris Melanoma.

Distinguishing an iris melanoma from an iris nevus can be challenging as few clinical features other than documented growth are helpful in making the diagnosis. In this study, we compared the presenting intraocular pressure (IOP) and cup-to-disc ratio (CDR) between affected and unaffected eyes in patients with iris melanoma and iris nevus. This was a single-institution retrospective case series of patients treated for iris melanoma and iris nevus from January 2013 to October 2022. Thirty-nine subjects with iris melanoma and forty age-matched patients with iris nevus were included. We analyzed the difference in IOP, CDR, and diagnosis of glaucoma between affected and unaffected eyes in patients with iris melanoma and control iris nevus cohort. The average IOP for eyes with iris melanoma and iris nevus was 18.8±6.1 mmHg and 14.6±3.5 mmHg (P<0.001), respectively. The average CDR was 0.36±0.27 and 0.24±0.14 (P=0.02), respectively. The average IOP of the contralateral unaffected eye in iris melanoma patients was 16.3±3.5 mmHg, significantly less than the affected eye (P=0.03). The average CDR of the contralateral unaffected eye in iris melanoma was 0.25±0.15, which was trending towards being less than the affected eye (P=0.05). There was no difference in the average IOP (P=0.89) or average CDR (P=0.49) between the affected and unaffected eye in patients with iris nevus. We demonstrate that patients with iris melanoma are more likely to have greater IOP and CDR in the affected eye compared to the unaffected eye, and a diagnosis of unilateral glaucoma than eyes with iris nevus. Patients with iris melanoma had greater IOP asymmetry between the affected and unaffected eye. Therefore, IOP and CDR asymmetry may suggest a diagnosis of iris melanoma.

Evaluation of bone-conducted oVEMPs using frontal medial and mastoid stimulations

AimsTo determine the optimal stimulation intensity for frontal stimulation with a modified slit lamp holder and to compare the reliability and symmetry of bone-conducted ocular vestibular evoked myogenic potentials (oVEMPs) using two stimulation sites: frontal medial and mastoid. MethodsThis observational study included 33 healthy volunteers (15 women, 18 men; mean age 24.5years) at the University Hospital of Lausanne. Participants underwent otoneurological assessments, and those with normal results were included. Bone-conducted oVEMPs were recorded using a Brüel and Kjaer mini-shaker type 4810. A modified slit lamp holder was used for frontal stimulation to ensure consistent application pressure, freeing the examiner's hands. Mastoid stimulation was performed manually. ResultsThe best reproducibility of oVEMP recordings was observed at 70dB nHL. Frontal stimulation demonstrated lower dispersion of data and lower asymmetry ratios of latencies (up to 7%) and amplitudes (up to 50%) compared to mastoid stimulation (up to 40% for latencies). Single stimulations at both frontal and mastoid sites were sufficient to obtain reliable measurements of both utricles. ConclusionFrontal stimulation at 70dB nHL using a modified slit lamp holder is recommended for bone-conducted oVEMP recordings due to its superior reproducibility, comfort, and reliability. This study establishes a new standard for optimal stimulation intensity and supports the use of frontal stimulation in clinical practice.

Comparison of Multifrequency Narrow-Band CE-Chirp and Tone Burst Evoked Cervical Vestibular Evoked Myogenic Potentials.

Cervical vestibular evoked myogenic potentials (cVEMPs) are inhibitory myogenic responses that have commonly been elicited using a variety of stimuli. Yet the comparison of the effects of multifrequency tone bursts and narrow-band Claus Elberling chirps (NB CE-chirps) on cVEMPs has never been studied in homogeneous age groups. The present study focused on comparing the effect of multifrequency NB CE-chirps and tone bursts on the various parameters of cVEMP responses in normal-hearing younger adults. A within-group study design was applied, and purposive sampling was utilized for the collection of the data sample. The present study involved the elicitation of NB CE-chirp and tone burst-evoked cVEMPs across four-octave frequencies in 25 normal-hearing younger adults. NB CE-chirp and tone burst evoked cVEMPs were found to have a 100% response rate for all frequencies except 4,000 Hz. Across frequencies, P1 and N1 latencies were seen to be significantly shorter for NB CE-chirps than tone bursts at 500 Hz and 1,000 Hz stimulation. No differences were seen in the P1N1 amplitudes and interaural asymmetry ratio between the two stimuli across all four-octave frequencies. Furthermore, we found a significantly higher number of ears tuned to NB CE-chirps than tone bursts at 500 Hz. Comparative differences in the latencies of cVEMP responses between and within stimuli could be due to the variation in stimuli duration. Also, the difference in amplitudes across stimulation frequencies might have resulted due to the predominance of saccular responses at lower mechanical resonance frequencies. Thus, the tuning was also seen at 500 Hz and was relatively higher for NB CE-chirps than tone bursts.

Chronic Unilateral Vestibular Hypofunction: Insights into Etiologies, Clinical Subtypes, Diagnostics and Quality of Life.

Background/Objectives: Chronic unilateral vestibular hypofunction (UVH) can lead to disabling vestibular symptoms and a decrease in quality of life. The aim of this study was to investigate etiologies, clinical subtypes, symptoms, and quality of life (QoL) in patients with chronic UVH. Methods: A retrospective study was performed on 251 UVH patients in a tertiary referral center. Inclusion criteria comprised reduced or absent caloric responses, with a caloric asymmetry ratio ≥25%. Patients with central vestibular pathology, symptom duration <3 months, and incomplete responses to questionnaires were excluded. Patient records were assessed for etiologies, secondary vestibular diagnoses, clinical subtypes, and questionnaires related to QoL. Additionally, multiple linear regression analysis was performed to evaluate factors influencing QoL. Results: Thirteen different etiologies were identified, with Menière's Disease as the most prevalent (31%, n = 79). The most frequently reported secondary vestibular diagnoses were benign paroxysmal positional vertigo (BPPV) (21%, n = 54) and persistent postural perceptual dizziness (PPPD) (19%, n = 47). Five distinct clinical subtypes were identified: recurrent vertigo with UVH (47%), rapidly progressive UVH (25%), idiopathic/unknown UVH (18%), slowly progressive UVH (8%), and congenital UVH (2%). Over 80% of UVH patients experienced moderate-to-severe handicap, as indicated by the Dizziness Handicap Inventory. Approximately 20-25% of UVH patients exhibited moderate-to-severe depression and anxiety, based on the Hospital Anxiety and Depression Scale. Multiple linear regression analyses demonstrated that the presence of PPPD significantly reduced QoL in chronic UVH patients. Conclusions: Chronic UVH is a heterogeneous disorder. Secondary vestibular diagnoses like BPPV and PPPD often co-exist and can significantly impact QoL. A structured diagnostic approach and tailored interventions are crucial to address the diverse needs of UVH patients.

Balance Impairment in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis.

Balance weaknesses related to mobility and fall risk in patients with rheumatic diseases are well-known. Vestibular dysfunction could negatively contribute to the balance ability of this patient population. This study aims to investigate the effects of Rheumatoid Arthritis (RA) and Ankylosing Spondylitis (AS), among the most common rheumatic diseases, on postural balance related to vestibular function. Seventy-eight participants were grouped as RA (n=34, 43%), AS (n=24, 30.7%), and the control group consisted of healthy individuals (n=20, 25.6%). Cervical Vestibular Evoked Myogenic Potentials (cVEMP) test, which assesses the vestibular function objectively, Dizziness Handicap Inventory (DHI), which evaluates vertigo subjectively, and Berg Balance Scale (BBS) were performed. Different degrees of VEMP latency prolongations were found in the AS and RA groups. Right, and left ear N1 latencies were significantly longer in the AS group than in RA and control. Right ear P1 latency prolongation was statistically significant in the RA group. Amplitude asymmetry ratio (AAR) was found to be considerably higher in the RA and AS groups than in the control group (p<0.05). The mean BBS score in the AS group was below the fall risk score of 45. A negative statistically significant effect was observed between latency prolongation and BBS in AS groups. The abnormal VEMP findings in individuals with RA and AS shows inner ear vestibular system dysfunction. This vestibular impairment strictly contributes to their postural imbalance and requires a focused vestibular rehabilitation program for balance treatment.

Near-pure red emission of highly thermally stable Eu3+ doped multi-component transparent oxyfluoride aluminosilicate glass-ceramic for red lasers and trichromatic WLEDs

In this paper, Eu3+ doped multi-component transparent aluminosilicate and oxyfluoride aluminosilicate glasses were fabricated by the melt-quenching procedure, and the glass-ceramics containing LiAlSi2O6 microcrystals (LAS glass-ceramics) were produced by a two-step heat treatment process. The XRD, SEM, and EDS data demonstrate that spherical single-phase LiAlSi2O6 microcrystals have precipitated from the glass matrices. The microhardness and flexural strength of the glass-ceramics vary in 6.27–6.66 GPa and 89.18–155.75 MPa, respectively. Phonon sideband analysis reveals that the phonon energies for both fluorine-containing and fluorine-free LAS glass-ceramics are approximately 971 cm−1, and the multiphonon relaxation rates (Wmp/W0) of the former are lower than those of the latter. Given its lower Wmp/W0 values, the fluorine-containing LAS glass-ceramic exhibits a higher emission intensity and a longer lifetime. Under 394 nm excitation, the fluorine-containing LAS glass-ceramic presents a warm and nearly pure red emission, characterized by a correlated color temperature of less than 3300 K and a color purity approaching 100 %. Time-resolved emission spectra support the photoluminescent stability of the Eu3+ ions. According to the Judd-Ofelt theory and spectral results, the fluorine-containing LAS glass-ceramic possesses lower Ω2/Ω4 and asymmetry ratios, leading to a more symmetrical local environment for the Eu3+ ions. Benefiting from its enhanced red emission, the 5D0→7F2 transition in the fluorine-containing LAS glass-ceramic exhibits a higher branching ratio (69.28 % > 50 %), emission cross-section (8.94 × 10−22 cm2), and gain bandwidth (12.12 × 10−28 cm3). Additionally, temperature-dependent photoluminescence spectra substantiate the excellent thermal stability of the Eu3+ doped fluorine-containing LAS glass-ceramic. Specifically, the intensity of the 5D0→7F2 transition at 150 °C remains 80 % of the initial intensity. Therefore, the Eu3+ doped multi-component transparent oxyfluoride aluminosilicate glass-ceramic has a significant competitive advantage in the field of red lasers and trichromatic WLEDs.

Anterior Sacroiliac Fracture Dislocation: A Comparative Radiologic analysis of Crescent Fractures in Pelvic Ring Injuries: A Retrospective Study.

Background and Objectives: Anterior sacroiliac fracture dislocation (ASFD), also known as locked pelvis, is a rarely reported diagnosis. The types of ASFDs are often misdiagnosed as lateral compression fractures due to the presence of crescent fractures. In this study, we distinguished ASFD from lateral compression fractures (LC 2) and studied their characteristics. Materials and Methods: This is a retrospective study involving patients from a Level 1 trauma center. Fifty-nine patients under the age of 65 years with crescent fractures caused by a high-energy mechanism were investigated. Results: The incidence of ASFD was 25% (15 of 59) in patients with crescent fractures. Among the 15 patients, 6 had override of the ilium over the sacrum, inhibiting reduction in the sacroiliac joint. Pre-operative radiographic evaluations revealed that vertical displacement of the ASFD was larger than that of lateral compression fracture (LC 2) in the outlet view (mean 9.5 vs. 1.9 mm, p = 0.013), and the pelvic asymmetry ratio was larger in ASFD (mean 7.8 vs. 4.1, p = 0.006) in the pelvis AP view. All patients achieved union after surgery. Post-operative radiography showed no significant vertical displacement difference. There was no difference in vascular injury or hemodynamic instability requiring embolization or preperitoneal pelvic packing (PPP) between the two groups. Conclusions: Patients with ASFD have greater vertical displacement and asymmetry compared to patients with LC 2 fractures. These fractures must be distinguished for appropriate reduction and anterior plate fixation.

Otolith function in Usher type II syndrome

Background Usher’s syndrome type II (USH2) is a rare genetic disorder encompassing hearing loss, vision impairment, and apparent intact vestibular function. Recent research suggests a potential involvement of the otolith vestibular receptors in USH2. Aims/Objectives Evaluate otolith dynamic function in USH2. Material and Methods Twenty-two USH2 (median age 53.9 ± 2.99) and age-matched controls underwent a complete battery vestibular testing including air conducted cervical and ocular vestibular evoked myogenic potentials (c-VEMPs and o-VEMPs). Vestibular function tests were correlated with Activities Balance Scale (ABC) and Dizziness Handicap Inventory (DHI) scores. Results Fourteen USH2 reported previous vertigo (vs none control). Among 88 ears, c-VEMPs were absent in 15 USH2 cases and 4 controls (p = 0.034), while o-VEMPs were absent in 22 USH2 cases and 12 controls (p = 0.129). There were significant differences between USH2 vs controls in right ear o-VEMP N1 latencies (median 11.60/10.40, p < 0.010), N1-P1 amplitudes (median 5.15/10.10, p < 0.003) and in o-VEMP N1-P1 asymmetry ratio (median 24.78/40.50, p < 0.014). USH2 showed a strong correlation between o-VEMP amplitude and DHI score (p = 0.003, ρ = 0.769). No association was found between vertigo and VEMPs subgroups. Conclusions and Significance Our findings suggest the presence of otolith dysfunction in USH2, which is independent from subjectively reported dizziness. Incorporating vestibular testing into USH2 evaluation and monitoring could enhance characterization of this multisensory disease.

Maternal heart rate variability at 3-months postpartum is associated with maternal mental health and infant neurophysiology

Previous research has demonstrated a critical link between maternal mental health and infant development. However, there is limited understanding of the role of autonomic regulation in postpartum maternal mental health and infant outcomes. In the current study, we tested 76 mother-infant dyads from diverse socioeconomic backgrounds when infants were 3-months of age. We recorded simultaneous ECG from dyads while baseline EEG was collected from the infant; ECG heart rate variability (HRV) and EEG theta-beta ratio and alpha asymmetry were calculated. Dyadic physiological synchrony was also analyzed to better understand the role of autonomic co-regulation. Results demonstrated that lower maternal HRV was associated with higher self-reported maternal depression and anxiety. Additionally, mothers with lower HRV had infants with lower HRV. Maternal HRV was also associated with higher infant theta-beta ratios, but not alpha asymmetry. Exploratory analyses suggested that for mother-infant dyads with greater physiological synchrony, higher maternal HRV predicted increased infant theta-beta ratio via infant HRV. These findings support a model in which maternal mental health may influence infant neurophysiology via alterations in autonomic stress regulation and dyadic physiological co-regulation.

Tweaking the structure and symmetry of Y2B2O7:Eu3+ by B-site engineering for efficient and thermally stable phosphor: Y2Zr2O7 versus Y2Ge2O7

There is an urgent need for synthesizing red emitting phosphor with high photoluminescence quantum yield (PLQY) and good thermal stability for high performing phosphor converted light emitting diodes (pc-LEDs) which are in demand to mitigate carbon emission. Here we have achieved the same through symmetry alteration and structural modification strategy which leads to high PLQY and improved thermal stability. In this work we have synthesized highly symmetric cubic fluorite Y2Zr2O7:Eu3+pyrochlore and replacing the B-site Zr4+by Ge4+ to lower the symmetry and induce structural change to tetragonal Y2Ge2O7:Eu3+ by organic solvent free solid state reactions. Among the three composition Y2Ge2O7: Eu is exhibiting higher emission intensity, higher asymmetry ratio and enhanced PLQY (32.3 %) by virtue of lower symmetry of tetragonal phase. On the other hand, higher thermal stability was achieved for Y2Zr2O7: Eu (97 % at 450 K) endowed by higher structural integrity and stability of pyrochlore phase.

Test-retest reliability of subjective visual vertical from different head-tilt angles in young healthy adults

Objective:To establish the normal values of subjective visual vertical （SVV） in different head deflection angles and analyze its test and retest reliability, in order to provide a reference for the clinical application of SVV in the evaluation of vestibular disorders. Methods:Thirty-one healthy young people were selected to wear VR glasses, and the SVV data were tested in five different head-tilt, namely, 0° in the upright head position, 45°in the left head position, 45° in the right head position, 90° in the left head position, and 90° in the right head position, and were re-tested 2 weeks later. Results:①The mean values of SVV at 5 different head-tilt angles of 0°, left 45°, right 45°, left 90°, and right 90° were -0.07±1.71, 4.30±5.39, -6.51±5.58, -3.76±7.42, and 0.40±8.02, respectively, The 95% confidence limits of SVV at 0°, left 45°, right 45°, left 90°, right 90°, and right 90° were （-3.42, 3.28）, （-6.26, 14.86）, （-17.45, 4.43）, （-18.30, 10.78）, and（-15.32, 16.12）, respectively; ②The absolute values of SVV at 4 different head-tilt angles of left 45°, right 45°, left 90°, and right 90° were 5.62±3.96, 6.90±5.07, 6.82±4.70 and 6.48±4.68, respectively. The 95% confidence limits of SVV at left 45°, right 45°, left 90°, right 90°, and right 90° were（0，12.11）,（0，15.21）,（0，14.53）and（0，14.16）, respectively. The asymmetry ratio is 10% for the absolute value of the 45 ° deviation and 3% for the absolute value of the 90° deviation; ③Intra-class correlation coefficients（ICC） for 0°, left 45°, right 45°, left 90°, right 90°were 0.757, 0.673, 0.674, 0.815, and 0.856, respectively. Conclusion:SVV has good retest reliability and high stability, and the SVV normal value data of different head deviation angles established in the present study can be used as a reference for the diagnosis and evaluation of vestibular disorders.

Iodine-123-Iomazenil Single-Photon Emission Computed Tomography Revealed Recovery of Neuronal Viability in Association With Improvement of Cognitive Dysfunction After Revascularization in Moyamoya Disease.

Recent studies indicate that 123I-iomazenil (123I-IMZ) single-photon emission computed tomography (SPECT) can demonstrate neuronal viability. Although cognitive dysfunction has been recognized as an important issue in adult patients with moyamoya disease (MMD), no standard neuroradiological methods to define such conditions have been established. We examined the relationship between cognitive function and 123I-IMZ SPECT before and after revascularization in patients with MMD. The study participants were 16 adult patients with MMD whose cerebrovascular reactivities were decreased only on the surgical sides of combined revascularization. Cognitive function was examined using the Mini-Mental State Examination (MMSE; cutoff: 27) and the Frontal Assessment Battery (FAB; cutoff: 16) before and at 3 to 6 months after surgery. 123I-iodoamphetamine (123I-IMP) SPECT with acetazolamide challenge and 123I-IMZ SPECT were performed concurrently while evaluating cognitive function. The radioreactivities of 123I-IMZ SPECT in regions with decreased cerebrovascular reactivities on 123I-IMP SPECT were investigated using affected-to-contralateral side asymmetry ratio (IMZ-ACR). Twelve patients showed normal cognitive function (MMSE: 29.8 ± 0.4, FAB: 18 ± 0) before surgery. No evident laterality of 123I-IMZ uptake was seen (IMZ-ACR: 0.98 ± 0.04). Neither cognitive function nor 123I-IMZ SPECT worsened after surgery (MMSE: 29.8 ± 0.3, FAB: 18 ± 0, IMZ-ACR: 1.00 ± 0.04). By contrast, 4 patients presented cognitive dysfunction (MMSE: 24.3 ± 3.9, FAB: 14.8 ± 2.7) before revascularization. Preoperative imaging of these patients showed decreased 123I-IMZ uptake, and their IMZ-ACRs (0.83 ± 0.08) were significantly lower than those of the normal group. After revascularization, cognitive functions and 123I-IMZ uptake tended to ameliorate (MMSE: 27.5 ± 1.7, FAB: 16.3 ± 2.2, IMZ-ACR: 0.94 ± 0.09). Preoperative cognitive function was associated with 123I-IMZ uptake in adult patients with MMD. After revascularization, cognitive function could be recovered in the viable areas of the brain, which is consistent with 123I-IMZ SPECT findings.

Joint k-ω Space Image Reconstruction and Data Fitting for Chemical Exchange Saturation Transfer Magnetic Resonance Imaging.

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is a novel MRI technology to image certain compounds at extremely low concentrations. Long acquisition time to measure signals at a set of offset frequencies of the Z-spectra and to repeat measurements to reduce noise pose significant challenges to its applications. This study explores correlations of CEST MR images along the spatial and Z-spectral dimensions to improve MR image quality and robustness of magnetization transfer ratio (MTR) asymmetry estimation via a joint k-ω reconstruction model. The model was formulated as an optimization problem with respect to MR images at all frequencies ω, while incorporating regularizations along the spatial and spectral dimensions. The solution was subject to a self-consistency condition that the Z-spectrum of each pixel follows a multi-peak data fitting model corresponding to different CEST pools. The optimization problem was solved using the alternating direction method of multipliers. The proposed joint reconstruction method was evaluated on a simulated CEST MRI phantom and semi-experimentally on choline and iopamidol phantoms with added Gaussian noise of various levels. Results demonstrated that the joint reconstruction method was more tolerable to noise and reduction in number of offset frequencies by improving signal-to-noise ratio (SNR) of the reconstructed images and reducing uncertainty in MTR asymmetry estimation. In the choline and iopamidol phantom cases with 10.5% noise in the measurement data, our method achieved an averaged SNR of 31.0 dB and 32.2 dB compared to the SNR of 24.7 dB and 24.4 dB in the conventional reconstruction approach. It reduced uncertainty of the MTR asymmetry estimation over all regions of interest by 54.4% and 43.7%, from 1.71 and 2.38 to 0.78 and 1.71, respectively.

Lung Volume and Pneumatization Changes in Children in Early Post-Surgical Period After Correction of Severe Neuromuscular Scoliosis Complicated with Respiratory Failure: Cohort Study

Background. The effect of spinal deformity surgical correction in children with severe neuromuscular scoliosis (NMS) on lung function remains unexplored. Objective. The aim of the study is to — to survey the dynamics of volume and structure of lungs pneumatization in children after surgical correction of severe neuromuscular deformities of the spine complicated by respiratory disorders. Methods. CT scans of lungs from 5 children with right-sided NMS, grade IV (Cobb angle &gt; 50°) and functional respiratory disorders (lung capacity &lt; 30% of normal value according to spirometry data and/or clinical signs of respiratory failure) were retrospectively studied. Right and left lungs volumes, their ratio (asymmetry index), indicators of distribution of tissue density of each lung (as a percentage of total volume) before (not earlier than 2 months) and after (not later than 3 months) surgical correction of scoliosis were determined via the data processing from CT scans of the thoracic spine. Results. All children had both lung volumes below reference values (healthy peers) before surgery. The right lung volume increased by 11% (6.4–40.6%), the left lung — by 41% (22.5–90%) with the asymmetry index approaching the reference values for the corresponding age after correction of spinal deformity (the value of scoliotic deformity decreased (median) from 94 to 68°). The volume of normal ventilation zones increased from 30 to 50% on the right side, and from 41 to 55% on the left side, primarily due to decrease in the volume of hypoventilation zones, but not atelectasis and emphysema. Conclusion. Surgical correction of spinal deformity in children with NMS, grade IV, complicated with respiratory failure led to normalization of lungs volume and tissue density characteristics already in the early postoperative period.

Hippocampal Glutamate Levels and Their Correlation With Subregion Volume in School-Aged Children With MRI-Negative Epilepsy: A Preliminary Study.

Abnormal levels of glutamate constitute a key pathophysiologic mechanism in epilepsy. The use of glutamate chemical exchange saturation transfer (GluCEST) imaging to measure glutamate levels in pediatric epilepsy is rarely reported in research. To investigate hippocampal glutamate level variations in pediatric epilepsy and the correlation between glutamate and hippocampal subregional volumes. Cross-sectional, prospective. A total of 38 school-aged pediatric epilepsy patients with structurally normal MRI as determined by at least two independent radiologists (60% males; 8.7 ± 2.5 years; including 20 cases of focal pediatric epilepsy [FE] and 18 cases of generalized pediatric epilepsy [GE]) and 17 healthy controls (HC) (41% males; 9.0 ± 2.5 years). 3.0 T; 3D magnetization prepared rapid gradient echo (MPRAGE) and 2D turbo spin echo GluCEST sequences. The relative concentration of glutamate was calculated through pixel-wise magnetization transfer ratio asymmetry (MTRasym) analysis of the GluCEST data. Hippocampal subfield volumes were computed from MPRAGE data using FreeSurfer. This study used t tests, one-way analysis of variance, Kruskal-Wallis tests, and Pearson correlation analysis. P < 0.05 was considered statistically significant. The MTRasym values of both the left and right hippocampi were significantly elevated in GE (left: 2.51 ± 0.23 [GE] vs. 2.31 ± 0.12 [HCs], right: 2.50 ± 0.22 [GE] vs. 2.27 ± 0.22 [HCs]). The MTRasym values of the ipsilateral hippocampus were significantly elevated in FE (2.49 ± 0.28 [ipsilateral] vs. 2.29 ± 0.16 [HCs]). The MTRasym values of the ipsilateral hippocampus were significantly increased compared to the contralateral hippocampus in FE (2.49 ± 0.28 [ipsilateral] vs. 2.35 ± 0.34 [contralateral]). No significant differences in hippocampal volume were found between different groups (left hippocampus, P = 0.87; right hippocampus, P = 0.87). GluCEST imaging have potential for the noninvasive measurement of glutamate levels in the brains of children with epilepsy. 2 TECHNICAL EFFICACY: Stage 1.