Changes In T2 Research Articles

Evaluation of the Upper Arch Morphological Changes after Two Different Protocols of Expansion in Early Mixed Dentition: Rapid Maxillary Expansion and Invisalign® First System.

Background: The objective of this retrospective study was to analyze the morphological changes of the upper arch after two protocols of expansion, the Invisalign® First system and rapid maxillary expansion (RME), in mixed dentition by means of geometric morphometric analysis (GMM). Methods: Digital dental casts of 32 children treated either with RME (RME group: 17 subjects; mean age 8.1 years) or the First system (First group: subjects; mean age 8.4 years) were collected. For both the RG and FG, pre-(T1) and post-treatment(T2) digital models were created. A total of 14 landmarks were digitized and GMM was applied. Procrustes analysis and principal component analysis (PCA) were performed. Results: The PC1 resulting from the T2–T1 comparison in the RG g showed statistically significant morphological changes in the posterior region of the upper arch shape, without significant variations in the anterior region. The comparison of the T2–T1 changes in the FG showed an increase in the transverse dimension at the level of the canine and the first deciduous molar widths, with morphological variation in the anterior region due to frontal teeth alignment. Conclusions: The First system induced shape modifications of the upper arch during expansion in contrast to RME. The FG presented an improvement in the maxillary arch shape, while the RG maintained the initial triangular shape.

Reduced Pollutant Emissions and Slagging Rate of Biomass Pellet Combustion by Optimizing the Multilayer Distribution of Secondary Air.

The utilization of coal and other fossil fuels is becoming increasingly restricted. Biomass, as a clean and renewable energy, plays a significant role in achieving zero carbon emissions. However, biomass is prone to slagging in the combustion process due to its high alkali metal content. The ash slagging rate and pollutant emission level of flue gas can be reduced by optimizing the air distribution, in order to decrease the fuel layer temperature in the combustion chamber. The results reveal opposite change trends of CO and NOx concentrations in the flue gas. The NOx emissions of corn stalk combustion under the multilayer secondary air distribution are obvious compared with those of rice husk combustion. The slagging rate of corn stalks is highly correlated with temperature T1 of the fuel bed. The silica ratio (G), alkali/acid ratio (B/A), Na content index (Na (index)), and alkaline index (Alc) cannot accurately predict the slagging tendency when temperature T1 changes. Therefore, the modified predictive index (Gt) was proposed to predict the slagging tendency of corn stalks with the combustion zone temperature T1 effectively. The experimental results can contribute to the efficient combustion and low pollutant emissions of biomass.

Local Patterns in 2-Year T1ρ and T2 Changes of Hip Cartilage Are Related to Sex and Functional Data: A Prospective Evaluation on Hip Osteoarthritis Participants.

Although T1ρ and T2 have emerged as early indicators for hip osteoarthritis (OA), there is little information regarding longitudinal changes across the cartilage in the early stages of this disease. To characterize the variability in 2-year hip cartilage T1ρ and T2 changes and investigate associations between these patterns of change and common indicators of hip OA. Prospective. A total of 25 women (age: 51.9 ± 16.3 years old; BMI: 22.6 ± 2.0 kg/m2 ) and 17 men (age: 55.8 ± 14.9 years old; body mass index (BMI): 24.4 ± 3.8kg/m2 ) who were healthy or with early-to-moderate hip OA. A 3 T MRI (GE), 3D combined T1ρ /T2 magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots. Principal component (PC) analysis of Z-score difference maps of 2-year changes in hip cartilage T1ρ and T2 relaxation times, participant hip disability and osteoarthritis outcome scores (HOOS) and functional tests at 2-year follow-up. Shapiro-Wilk test, unpaired t-tests, Kruskal Wallis tests, Pearson or Spearman (ρ) correlations. Significance was set at P < 0.05. Women (-6.40 ± 14.48) had significantly lower T1ρ PC1 scores than men (10.05 ± 26.15). T1ρ PC4 was significantly correlated with HOOSsport , HOOSsymptoms , HOOSpain , HOOSadl , and HOOSqol at 2-year follow-up (ρ: [0.36, 0.50]). T1ρ PC2 and PC4 were significantly correlated with 30-second chair test (ρ=-0.39 and ρ=0.24, respectively) and side plank (ρ=-0.32 and ρ=0.21). T1ρ and T2 PC2 were significantly correlated with 40 m walk test (ρ=0.34 and ρ=0.31) and 30-second chair rise test (ρ=-0.39 and ρ=-0.32). Men exhibited accelerated T1ρ increases across the femoral cartilage compared to women, suggesting sex should be considered when evaluating early hip OA. Participants with poorer HOOS and function exhibited greater T1ρ and T2 increases in superior and anterior femoral cartilage and greater T1ρ increases in the anterior femoral cartilage. These patterns of short-term relaxometry increases could indicate hip OA progression. 2 TECHNICAL EFFICACY: Stage 3.

Redirecting mandibular growth through orthodontic dentoalveolar height development in growing patients with Class III malocclusion undergoing maxillary orthopedic protraction

To control mandibular growth could be the determining factor for any growing patients with Class III malocclusion undergoing maxillary orthopedics. It has been reported that orthodontic dentoalveolar height development (ODHD) through orthodontic total arch extrusion might redirect mandibular growth backward and downward in growing patients with Class III malocclusion. We hypothesized bimaxillary-ODHD (bimax-ODHD) should be equal to or exceed the mandibular condylar growth to redirect the mandible to grow downward and backward in growing patients with Class III malocclusion. Twenty-seven consecutive growing patients with Class III malocclusion who underwent maxillary orthopedics (MO) were recruited in this study, including 13 control patients (aged 12.70 ± 2.09 years) who underwent treatment of MO with no ODHD and another 14 patients who underwent MO and ODHD (ODHD group; aged 12.75 ± 1.40 years). The pretreatment (T1) and posttreatment (T2) CBCT images were superimposed and measured for the amount of ODHD and maxillary downward growth (ODHD-Mx), ODHD in the mandible (ODHD-Mn), T2 - T1 changes on facial convexity, y-axis, maxillary and condylar growth, and mandibular posture. The data were analyzed statistically. The T2 - T1 treatment duration was 7.5 months, significantly (P= 0.028) shorter in the ODHD group. The maxillary and condylar growth were similar among the groups. The mandible grew forward and downward in the control group, the ODHD-Mx and ODHD-Mn were significantly (P= 0.011) more in the ODHD group, and the mandible significantly (P= 0.001) grew backward and downward. The mandible grew backward and downward when the bimax-ODHD (ODHD-Mx+ ODHD-Mn) exceeded the condylar growth (r= 0.715; P<0.001). The bimax-ODHD, including the downward growth of the maxilla, should be equal to or exceed the mandibular condylar growth to redirect the mandible to grow downward and backward and improve the skeletal facial convexity in growing patients with Class III malocclusion.

Association of Superficial Cartilage Transverse Relaxation Time With Osteoarthritis Disease Progression: Data From the Foundation for the National Institutes of Health Biomarker Study of the Osteoarthritis Initiative.

To study whether layer-specific cartilage transverse relaxation time (T2) and/or longitudinal change is associated with clinically relevant knee osteoarthritis (OA) disease progression. The Foundation for the National Institutes of Health Biomarker Consortium was a nested case-control study on 600 knees from 600 Osteoarthritis Initiative participants. Progressor knees had both medial tibiofemoral radiographic joint space width (JSW) loss (≥0.7 mm) and a persistent increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score (≥9 on a 0-100 scale) at 24-48 months from baseline (n=194). Multiecho spin-echo (MESE) magnetic resonance images (MRIs) for cartilage T2 analysis had been acquired in the right knees only (97 progressor knees). These were compared to 104 control knees without JSW or pain progression. Fifty-three knees had JSW progression, and 57 pain progression only. Cartilage thickness segmentations obtained from double-echo steady-state MRI were matched to MESE MRI to extract superficial and deep femorotibial cartilage T2. Superficial medial femorotibial compartment (MFTC) T2 at baseline was the primary, and change in deep MFTC T2 between baseline and 12 months was the secondary analytic outcome of this post hoc exploratory study. Baseline superficial MFTC T2 was significantly elevated in progressor knees (adjusted mean 47.2 msec [95% confidence interval (95% CI) 46.5, 48.0]) and JSW progression only knees (adjusted mean 47.3 msec [95% CI 46.3, 48.3]), respectively, versus non-progressor knees (45.8 msec [95% CI 45.0, 46.5]) after adjustment for age, sex, body mass index, WOMAC pain score, and medial joint space narrowing grade (analysis of covariance). Change in T2 was not significantly associated with case status. Baseline superficial, but not deep, medial cartilage T2 is associated with clinically relevant disease progression in knee OA.

Muscle activity with 0.5 T upright MRI-DESS to measure T2 in biceps and triceps.

The purpose of this study was to determine if muscle activity of the biceps followed by isometric flexion changes T2 measured in the biceps. It is hypothesized that an increase in T2 will be observed in the biceps but not in the triceps after flexion exercise. Ten healthy volunteers were imaged with a one-channel neck coil while seated in a 0.5 T upright open magnetic resonance imaging (MRI) scanner using a three-dimensional double echo steady-state (DESS) sequence. Volunteers were imaged while relaxing their arm for 10, 20, and 30 minduring an isometric biceps flexion immediately following performance of biceps curls to exhaustion, and again after relaxing for 10 and 20 min. Voxel-wise T2 was calculated by fitting to a DESS signal equation in regions segmented at muscle centers to determine mean T2 . During isometric biceps flexion immediately following biceps curls, mean T2 increased (average 33%, p < 0.05) in the biceps but not in the triceps. By 20 min after curls, mean T2 decreased (p < 0.05), and was near preactivity values. In contrast, there was no change in triceps T2 across any activity or postactivity time points. Intra-rater repeatability was excellent (ICC: 0.90-0.97). This study demonstrated that measuring T2 in an active muscle is feasible using a DESS sequence in an upright open MRI scanner. This could enable the study of muscle function while the muscle is working and weight-bearing, rather than of the "fatigue" of the muscles after activity. In comparison to electromyography, MRI also enables the study of deep muscles and allows simultaneous assessment of activity and function.

Ternary Alloy PtWMn as a Mn Nanoreservoir for High‐Field MRI Monitoring and Highly Selective Ferroptosis Therapy

Ferroptosis exhibits potential to damage drug-resistant cancer cells. However, it is still restricted with the "off-target" toxicity from the undesirable leakage of metal ions from ferroptosis agents, and the lack of reliable imaging for monitoring the ferroptosis process in living systems. Herein, we develop a novel ternary alloy PtWMn nanocube as a Mn reservoir, and further design a microenvironment-triggered nanoplatform that can accurately release Mn ions within the tumor to increase reactive oxygen species (ROS) generation, produce O2 and consume excess glutathione for synergistically enhancing nonferrous ferroptosis. Moreover, this nanoplatform exerts a responsive signal in high-field magnetic resonance imaging (MRI), which enables the real-time report of Mn release and the monitoring of ferroptosis initiation through the signal changes of T1 -/T2 -MRI. Thus, our nanoplatform provides a novel strategy to store, deliver and precisely release Mn ions for MRI-guided high-specificity ferroptosis therapy.

Microstructure in patients with visual snow syndrome: an ultra-high field morphological and quantitative MRI study.

Visual snow syndrome is a neurological condition characterized by continuous visual disturbance and a range of non-visual symptoms, including tinnitus and migraine. Little is known about the pathological mechanisms underlying visual snow syndrome. Here, we assessed brain morphometry and microstructure in visual snow syndrome patients using high-resolution structural and quantitative MRI. Forty visual snow syndrome patients (22 with migraine) and 43 controls underwent 7-Tesla MRI (MP2RAGE, 0.75 mm isotropic resolution). Volumetric and quantitative T1 values were extracted for white and grey matter regions and compared between groups. Where regions were significantly different between groups (false discovery rate corrected for multiple comparisons), post hoc comparisons were examined between patients with and without migraine. For visual snow syndrome patients, significant MRI variables were correlated with clinical severity (number of visual symptoms, perceived visual snow intensity, disruptiveness, fatigue and quality of life) and psychiatric symptoms prevalent in visual snow syndrome (depression, anxiety and depersonalization). Finally, cortical regions and individual thalamic nuclei were studied. Compared with controls, visual snow syndrome patients demonstrated a trend towards larger brain and white matter volumes and significantly lower T1 values for the entire cortex (P < 0.001), thalamus (P = 0.001) and pallidum (P = 0.001). For the patient group, thalamic T1 correlated with number of visual symptoms (P = 0.019, r = 0.390) and perceived disruptiveness of visual snow (P = 0.010, r = 0.424). These correlations did not survive multiple comparison corrections. As for specificity in visual snow syndrome group, T1 changes were most evident in caudal regions (occipital cortices) followed by parietal, temporal and prefrontal cortices. T1 values differed between groups for most individual thalamic nuclei. No differences were revealed between patients with and without migraine. In visual snow syndrome patients, we observed no changes in morphometry, instead widespread changes in grey matter microstructure, which followed a caudal-rostral pattern and affected the occipital cortices most profoundly. Migraine did not appear to independently affect these changes. Lower T1 values may potentially result from higher neurite density, myelination or increased iron levels in the visual snow syndrome brain. Further investigation of these changes may enhance our understanding of the pathogenesis of visual snow syndrome, ultimately leading to new treatment strategies.

Ternary Alloy PtWMn as a Mn Nanoreservoir for High‐Field MRI Monitoring and Highly Selective Ferroptosis Therapy

AbstractFerroptosis exhibits potential to damage drug‐resistant cancer cells. However, it is still restricted with the “off‐target” toxicity from the undesirable leakage of metal ions from ferroptosis agents, and the lack of reliable imaging for monitoring the ferroptosis process in living systems. Herein, we develop a novel ternary alloy PtWMn nanocube as a Mn reservoir, and further design a microenvironment‐triggered nanoplatform that can accurately release Mn ions within the tumor to increase reactive oxygen species (ROS) generation, produce O2and consume excess glutathione for synergistically enhancing nonferrous ferroptosis. Moreover, this nanoplatform exerts a responsive signal in high‐field magnetic resonance imaging (MRI), which enables the real‐time report of Mn release and the monitoring of ferroptosis initiation through the signal changes of T1‐/T2‐MRI. Thus, our nanoplatform provides a novel strategy to store, deliver and precisely release Mn ions for MRI‐guided high‐specificity ferroptosis therapy.

Gelatin-Agar Liver Phantom to Simulate Typical Enhancement Patterns of Hepatocellular Carcinoma for MRI

Background: Hepatocellular carcinoma (HCC) is one of the most common cause of cancer-related deaths worldwide. The objective of this study is to detect the various stages of HCC through the utilization of a dynamic liver phantom with MRI. Methods: Three liver phantoms composed of different gelatin concentrations (2.5%wt, 4.0%wt, and 5.0%wt) and fixed agar concentrations were used. The HCC samples consisted of agarose and glycerol and were of varying sizes (0.5,1.0, and 2.0cm). The chemical, mechanical, electrical, and imaging properties of the phantoms were examined. The consistency of T1 and T2 signal intensities over a six-week period was studied. In addition, dynamic contrast-enhanced MRI was used to detect the HCC samples through the Dixon sequence. Results: The gelatin concentration of 5%wt was the most stable in regard to density, exhibited the lowest average compressive strength of 0.22MPa, and had the lowest electrical conductivity over the course of a six-week period. During this time, an increase in the T1 signal intensity was observed as the gelatin concentration in the sample increased. On the contrary, the least change in T1 and T2 was noted in the first sample with the 2.5% wt of gelatin. The HCC samples simulated the typical appearance of HCC, with the minimum sample size the body coil could detect being 1cm. Conclusion: Typical Enhancement patterns of HCC were simulated under MRI.

Assessment of Fasudil on Contrast-Associated Acute Kidney Injury Using Multiparametric Renal MRI.

Aims: To evaluate the utility of fasudil in a rat model of contrast-associated acute kidney injury (CA-AKI) and explore its underlying mechanism through multiparametric renal magnetic resonance imaging (mpMRI). Methods: Experimental rats (n = 72) were grouped as follows: controls (n = 24), CA-AKI (n = 24), or CA-AKI + Fasudil (n = 24). All animals underwent two mpMRI studies (arterial spin labeling, T1 and T2 mapping) at baseline and post iopromide/fasudil injection (Days 1, 3, 7, and 13 respectively). Relative change in renal blood flow (ΔRBF), T1 (ΔT1) and T2 (ΔT2) values were assessed at specified time points. Serum levels of cystatin C (CysC) and interleukin-1β (IL-1β), and urinary neutrophil gelatinase-associated lipocalin (NGAL) concentrations were tested as laboratory biomarkers, in addition to examining renal histology and expression levels of various proteins (Rho-kinase [ROCK], α-smooth muscle actin [α-SMA]), hypoxia-inducible factor-1α (HIF-1α), and transforming growth factor-β1 (TGF-β1) that regulate renal fibrosis and hypoxia. Results: Compared with the control group, serum levels of CysC and IL-1β, and urinary NGAL concentrations were clearly increased from Day 1 to Day 13 in the CA-AKI group (all p < 0.05). There were significant reductions in ΔT2 values on Days 1 and 3, and ΔT1 reductions were significantly more pronounced at all time points (Days 1–13) in the CA-AKI + Fasudil group (vs. CA-AKI) (all p < 0.05). Fasudil treatment lowered expression levels of ROCK-1, and p-MYPT1/MYPT1 proteins induced by iopromide, decreasing TGF-β1 expression and suppressing both extracellular matrix accumulation and α-SMA expression relative to untreated status (all p < 0.05). Fasudil also enhanced PHD2 transcription and inhibition of HIF-1α expression after CA-AKI. Conclusions: In the context of CA-AKI, fasudil appears to reduce renal hypoxia, fibrosis, and dysfunction by activating (Rho/ROCK) or inhibiting (TGF-β1, HIF-1α) certain signaling pathways and reducing α-SMA expression. Multiparametric MRI may be a viable noninvasive tool for monitoring CA-AKI pathophysiology during fasudil therapy.

Quantification of changes in myocardial T1 * values with exercise cardiac MRI using a free-breathing non-electrocardiograph radial imaging.

To develop and evaluate a free breathing non-electrocardiograph (ECG) myocardial T1 * mapping sequence using radial imaging to quantify the changes in myocardial T1 * between rest and exercise (T1 *reactivity ) in exercise cardiac MRI (Ex-CMR). A free-running T1 * sequence was developed using a saturation pulse followed by three Look-Locker inversion-recovery experiments. Each Look-Locker continuously acquired data as radial trajectory using a low flip-angle spoiled gradient-echo readout. Self-navigation was performed with a temporal resolution of ∼100 ms for retrospectively extracting respiratory motion. The mid-diastole phase for every cardiac cycle was retrospectively detected on the recorded electrocardiogram signal using an empirical model. Multiple measurements were performed to obtain mean value to reduce effects from the free-breathing acquisition. Finally, data acquired at both mid-diastole and end-expiration are picked and reconstructed by a low-rank plus sparsity constraint algorithm. The performance of this sequence was evaluated by simulations, phantoms, and in vivo studies at rest and after physiological exercise. Numerical simulation demonstrated that changes in T1 * are related to the changes in T1 ; however, other factors such as breathing motion could influence T1 * measurements. Phantom T1 * values measured using free-running T1 * mapping sequence had good correlation with spin-echo T1 values and was insensitive to heart rate. In the Ex-CMR study, the measured T1 * reactivity was 10% immediately after exercise and declined over time. The free-running T1 * mapping sequence allows free-breathing non-ECG quantification of changes in myocardial T1 * with physiological exercise. Although, absolute myocardial T1 * value is sensitive to various confounders such as B1 and B0 inhomogeneity, quantification of its change may be useful in revealing myocardial tissue properties with exercise.

T2*-Mapping of Knee Cartilage in Response to Mechanical Loading in Alpine Skiing: A Feasibility Study.

Purpose: This study intends to establish a study protocol for the quantitative magnetic resonance imaging (qMRI) measurement of biochemical changes in knee cartilage induced by mechanical stress during alpine skiing with the implementation of new spring-loaded ski binding. Methods: The MRI-knee-scans (T2*-mapping) of four skiers using a conventional and a spring-loaded ski binding system, alternately, were acquired before and after 1 h/4 h of exposure to alpine skiing. Intrachondral T2* analysis on 60 defined regions of interest in the femorotibial knee joint (FTJ) was conducted. Intra- and interobserver variability and relative changes in the cartilage T2* signal and thickness were calculated. Results: A relevant decrease in the T2* time after 4 h of alpine skiing could be detected at the majority of measurement times. After overnight recovery, the T2* time increased above baseline. Although, the total T2* signal in the superficial cartilage layers was higher than that in the lower ones, no differences between the layers in the T2* changes could be detected. The central and posterior cartilage zones of the FTJ responded with a stronger T2* alteration than the anterior zones. Conclusions: For the first time, a quantitative MRI study setting could be established to detect early knee cartilage reaction due to alpine skiing. Relevant changes in the T2* time and thus in the intrachondral collagen microstructure and the free water content were observed.

P.079 MT-TA: A mitochondrial genome cause of developmental and epileptic encephalopathy

Background: MT-TA (OMIM 590000), one of 22 mitochondrial transfer-RNA (mt-tRNA) genes, encodes the mt-tRNA for alanine. Pathogenic variants in mt-tRNA genes affect the translation of respiratory chain complexes I, III, and IV; which leads to mitochondrial dysfunction and a clinically variable phenotype. MT-TA pathogenic variants have been described in only seven patients, all of whom had isolated myopathy Methods: Case report. Results: Our patient initially presented with drug-resistant West syndrome, later evolving towards a Lennox Gastaut phenotype. Although she had hypotonia, serum creatine kinase and electromyography were normal. Brain-MRI showed bilateral symmetric hypointense T1, hyperintense T2-fluid-attenuated-inversion-recovery and restricted-diffusion signal changes in the dentate nuclei. Mitochondrial genome testing identified a previously published pathogenic variant in MT-TA (m.5591G&gt;A) with 14% blood heteroplasmy and 16% urine heteroplasmy. The variant was absent in serum sampled from the patient’s mother Conclusions: Our case extends the phenotypic spectrum of MT-TA variants to include developmental and epileptic encephalopathy, in the apparent absence of muscle disease. We hypothesize that our patient may have the greatest degree of heteroplasmy in brain tissue; however, animal models and induced pluripotent stem cell (iPSC) models are needed to identify the precise mechanism by which MT-TA dysfunction results in variable phenotypes with variable degrees of heteroplasmy.

Characterization of proton T2 relaxation time of bovine lactoferrin powder before and after high-temperature storage

Proton T2 relaxation is a useful parameter for investigating the motion of and interaction between dried proteins and water molecules. This study aimed to investigate the relationship of proton T2 relaxation with aggregation and water hydration or dehydration in five bovine lactoferrin powders (LFs) before and after storage at 40 °C or 50 °C. Using time-domain nuclear magnetic resonance (TD-NMR), we detected T2short and T2long with different relaxation times. The two fractions and their average T2 relaxation time (T2) were used for analysis. Average T2 was positively correlated with the pre-storage water content. For the 40°C-storage test, T2 increased in all LFs; this increase can be explained by the monomer loss rate and change in water content. Conversely, for the 50°C-storage test, the change in T2 was correlated with the change in water content. Furthermore, the tendency for change in T2 showed variation with the monomer ratio and water content before storage. Thus, this study provides a novel insight that the factors contributing to the change in T2 during storage vary with storage temperature. In addition, we suggested that the T2 relaxation time was not sufficient as a predictor of susceptibility to aggregation.

Catalytic reductive ring opening of epoxides enabled by zirconocene and photoredox catalysis

Catalytic reductive ring opening of epoxides enabled by zirconocene and photoredox catalysis

The influence of tone on proximal femoral and acetabular geometry in neuromuscular hip displacement: A comparison of cerebral palsy and spinal muscular atrophy.

Purpose:The aim of this article was to compare longitudinal changes in hip morphology in cerebral palsy (hypertonic) and spinal muscular atrophy (hypotonic) to examine the influence of muscle tone on development of hip displacement.Methods:Children with spinal muscular atrophy (Types I and II) and cerebral palsy (Gross Motor Function Classification System IV and V) with hip displacement (migration percentage >30%) were included. Head shaft angle, migration percentage, and acetabular index were measured at T1 (1–2.5 years), T2 (3–5 years), and T3 (6–8 years). Analysis of variance testing and linear regression were utilized.Results:Sixty patients (cerebral palsy, N = 41; spinal muscular atrophy, N = 19) were included. Hip displacement occurred earlier in spinal muscular atrophy (34 months) than cerebral palsy (49 months) (p = 0.003). Head shaft angle was high and did not change between T1, T2, and T3, but significant changes in migration percentage were found (cerebral palsy: 23%, 36%, 45% (p < 0.01) and spinal muscular atrophy: 37%, 57%, 61% (p = 0.02)). Migration percentage increased by age in cerebral palsy (r = 0.41, p < 0.001), but not in spinal muscular atrophy (r = 0.18, p = 0.09). Acetabular index increased with migration percentage (cerebral palsy: r = 0.41, p < 0.001; spinal muscular atrophy: r = 0.48, p < 0.001).Conclusion:Persistent lateral physeal tilt by head shaft angle was found for both spinal muscular atrophy and cerebral palsy. Abnormal physeal alignment may be causally related to weakness of the hip abductor muscles rather than spasticity or muscle imbalance, resulting in coxa valga and secondary acetabular dysplasia.Level of evidence:III (case–control study).

ON THE ASSOCIATION BETWEEN DEEP LEARNING ASSESSED MRI MORPHOLOGICAL PHENOTYPE AND 4-YEARS CHANGES IN CARTILAGE THICKNESS AND T2 RELAXATION TIMES

Purpose: Previous studies have leveraged deep learning to identify morphological phenotypes as well as to compute T2 relaxation times and change in cartilage thickness on the Osteoarthritis Initiative (OAI) knee MRI dataset. Deep learning-generated ROAMES phenotyping of osteoarthritis (OA) has been demonstrated to predict incidence of structural and symptomatic OA as well as likelihood of total knee replacement (TKR) within 96 months. While associations vary by cartilage compartment, T2 relaxation times have also been associated with OA incidence and TKR after 5 years.

Using magnetic resonance fingerprinting to characterize periventricular nodular heterotopias in pharmacoresistant epilepsy.

We aimed to use a novel magnetic resonance fingerprinting (MRF) technique to examine in vivo tissue property characteristics of periventricular nodular heterotopia (PVNH). These characteristics were further correlated with stereotactic-electroencephalographic (SEEG) ictal onset findings. We included five patients with PVNH who had SEEG-guided surgery and at least 1 year of seizure freedom or substantial seizure reduction. High-resolution MRF scans were acquired at 3 T, generating three-dimensional quantitative T1 and T2 maps. We assessed the differences between T1 and T2 values from the voxels in the nodules located in the SEEG-defined seizure onset zone (SOZ) and non-SOZ, on -individual and group levels. Receiver operating characteristic analyses were performed to obtain the optimal classification performance. Quantification of SEEG ictal onset signals from the nodules was performed by calculating power spectrum density (PSD). The association between PSD and T1 /T2 values was further assessed at different frequency bands. Individual-level analysis showed T1 was significantly higher in SOZ voxels than non-SOZ voxels (p<.05), with an average 73% classification accuracy. Group-level analysis also showed higher T1 was significantly associated with SOZ voxels (p<.001). At the optimal cutoff (normalized T1 of 1.1), a 76% accuracy for classifying SOZ nodules from non-SOZ nodules was achieved. T1 values were significantly associated with ictal onset PSD at the ultraslow, θ, β, γ, and ripple bands (p<.05). T2 values were significantly associated with PSD only at the ultraslow band (p<.05). Quantitative MRF measures, especially T1 , can provide additional noninvasive information to separate nodules in SOZ and non-SOZ. The T1 and T2 tissue property changes carry electrophysiological underpinnings relevant to the epilepsy, as shown by their significant positive associations with power changes during the SEEG seizure onset. The use of MRF as a supplementary noninvasive tool may improve presurgical evaluation for patients with PVNH and pharmacoresistant epilepsy.

Development of a novel task-based functional magnetic resonance imaging phantom based on a bubble-compression approach.

Phantoms used in previous functional magnetic resonance imaging (fMRI) studies have drawbacks, such as a complicated circuit and equipment use, a single signal-change rate, and T2 * values that do not correspond to those of living human brains. We aimed to develop a phantom for use in task-based fMRI studies (gradient-echo echo-planar imaging; GRE-EPI) with bioequivalent T1 and T2 * values, using an innovative method to control the rate of signal change. A gel phantom with T1 and T2 * values equivalent to that of the living brain gray matter was fixed in a 150mm diameter container, with five holes, each of which could hold a 30-ml syringe. The gel phantom contained microscopic air bubbles; this made it possible to control the percent signal change by injector-induced water pressure changes. Using this phantom, we investigated the percent signal change, derived an equation that can approximately reproduce an arbitrary percent signal change, compared different gel phantom samples, investigated the change in relaxation time and bubble size during signal change, and assessed the change in values in each sample over time. The relaxation time of the gel phantom was similar to the literature values for gray matter. The percent signal change achieved was approximately 0%-13.51% and was dependent on the water pressure change. The derived equation was y=0.000008x3 - 0.000771x2 + 0.034222x - 0.026054, with y being the percent signal change and x being the pressure in kPa; the reproducibility was high. No significant difference was detected among samples of gray matter gel phantoms (P>0.05). The change in the rate of signal change with the change in water pressure was due to the change in T2 * value with the change in bubble size. With pressure increasing from 0 to 151.7kPa, the T2 * value increased from 52ms to 85ms. The newly developed gel phantom was stable for 60 days, but its bubble size changed after 21 days. We developed a novel phantom for use in fMRI, which could reproduce minute signal changes similar to the blood-oxygen-level-dependent effect and with bioequivalent T1 and T2 * values, and used an innovative method to control the percent signal change by compressing the air contained in the phantom for validation of fMRI using GRE-EPI. This phantom reproduced the percent signal change due to changes in T2 * values, which is very similar to scanning a human body. This phantom is expected to be a powerful tool for advancing the study of task-based fMRI.