Changes In T2 Research Articles

RADT-08. BASAL GANGLIA TOXICITY FOLLOWING PROTON THERAPY OF THE PINEAL REGION WITH BILATERAL ACTION-INDUCED MYOCLONUS

Abstract INTRODUCTION We sought to evaluate the toxicity profile for children receiving 54Gy to the pineal region with a significant dose delivered to posterior thalamus and basal ganglia. METHODS We performed a retrospective review of patients treated at a single institution with intensity modulated proton therapy (IMPT) receiving 54Gy to the pineal region. Multiple beam angles were utilized for planning. Patient characteristics and dosimetric data were correlated with late-toxicity and imaging. RESULTS From 2021-2023, six children were treated, and at a median follow-up of 13 months [9-26], all patients remain disease-free. Three patients had non-germinomatous germ cell tumors, 1 low-grade glioma, 1 atypical teratoid rhabdoid tumor (ATRT), and 1 embryonal tumor with multilayered rosettes. Age range was 2.4 to 16.8 years. All patients received chemotherapy prior to IMPT. Neuropsychological evaluation indicated range of intellectual functioning (mean = 98.3 [83-118]). One patient, a 4-year-old female with ATRT, developed T2 changes within the globus pallidus and thalamus on 3 month follow-up. At 5 months, she developed bilateral action-induced myoclonus with corresponding enhancing lesions in the globus pallidus bilaterally. Neuropsychological evaluation at 5 months post-treatment indicated memory impairments. She was treated with dexamethasone without improvement. Between 912 months post-treatment, tremors improved with physical therapy and imaging showed near complete resolution of enhancement within globus pallidus. CONCLUSION One of six children developed grade 3 toxicity manifesting as bilateral action-induced myoclonus with imaging changes in the globus pallidus bilaterally following IMPT and exhibited related neuropsychological deficits. While brainstem toxicity from IMPT is well documented, globus pallidus toxicity is not well characterized. Given the contiguous neuronal tracts with the brainstem, it is logical to apply similar treatment planning techniques, i.e. minimizing hotspots within the globus pallidus and thalamic “core” structures, and being cognizant of LET/RBE effects for treatment involving the pineal region in young children.

Pedestrian-ground contact injury protection method under the constraint of the vehicle-front end shape and its robust analysis

This research paper introduces a novel approach for protecting pedestrians from ground contact injuries through incorporating vehicle front-end shape constraints in the braking control method. The feasibility of the proposed method is evaluated through simulations, and its resilience to different disturbances is studied. Results indicate that the proposed method effectively manages vehicle movement by monitoring the first head-vehicle contact time (t1 ) between the pedestrian’s head and the vehicle. The simulations show that the proposed method reduces ground-related Weighted Injury Cost (WIC) by up to 84%, and the proportion of ‘safe’ mechanisms increases to 74%. The robustness of the braking control method is also evidenced by its high performance during disturbances such as changes in friction coefficient, lag time, and t1 . Furthermore, the anti-disturbance abilities of each vehicle shape are comparable except for t1 disturbance. There are no significant variations in the braking control protection effect between different friction coefficients and each t1 , but noticeable differences exist between lag times. Further analysis reveals that parameter disturbances affect the deceleration of the vehicle and the impact speed of the pedestrian and vehicle, leading to changes in the Vz (Vertical head-to-ground impact velocity), thorax acceleration, pelvic lateral impact force, and knee lateral bending angle, which subsequently increases the risk of pedestrian ground contact injuries. The proposed method offers an efficient solution for protecting pedestrians from ground contact injuries by controlling vehicle braking, highlighting its practical utility.

MRI-based sensing of pH-responsive content release from mesoporous silica nanoparticles

A proof of principle study toward developing a novel methodology which could be applicable for a non-invasive monitoring of the release of cargo molecules from therapeutic and diagnostic nanoparticles, as well as for possible monitoring of tissue pH variations. This was achieved by quantifying changes in longitudinal relaxation time (T1) before and after the pH-responsive release of contrast agents, for magnetic resonance imaging (MRI), from the pores of mesoporous silica nanoparticles (MSNs). The pores were filled with the FDA-approved contrast agent Gadobutrol (GdB), and its retention inside the pores ensured by covalent attachment of β-cyclodextrin monoaldehyde to hydrazine-functionalized MSN, through acidification-cleavable hydrazone linkage. The release kinetics of GdB was measured by fluorescence spectroscopy which revealed that the release of the contrast agent was enhanced at pH 5.0 in comparison to the release at pH 6.0 and 7.4. Furthermore, the changes in T1, occurring in response to the enhanced release of GdB from the pores of MSN at weakly acidic conditions, were successfully demonstrated by MRI measurements. It is envisioned that this approach using contrast agent-loaded nanoparticles before the treatment with the drug-filled analogs, could be applied in the future for tracking the locations and efficacies of nanomedicines for therapeutic cargo delivery.Graphical Pores of of β-maleimidopropionic acid hydrazide (BMPH)-functionalized mercaptopropyl-functionalized mesoporous silica nanoparticles (MPMSNs) were loaded with the contrast agent Gadobutrol and capped with β-cyclodextrin monoaldehyde. In weakly acidic environment the release of contrast agents was induced, and the enhanced release of GdB at pH 5.0 vs. pH 7.4 was evidenced by magnetic resonance imaging measurements.

Adverse myocardial and vascular side effects of immune checkpoint inhibitors: a prospective multimodal cardiovascular assessment.

Immune checkpoint inhibitors (ICIs) can induce cardiovascular toxicities. To prospectively assess the incidence of major cardiovascular events (MACE) on ICIs in solid cancer patients: myocarditis, pericarditis, acute coronary syndrome, heart failure, high-degree conduction abnormalities or sustained ventricular arrhythmias, or cardiovascular death at 6weeks (early MACE), including asymptomatic clinical changes by an independent adjudication committee using current recommended diagnostic criteria. The secondary objective was the incidence of the above-mentioned events adding atrial fibrillation (AF) at 6months (late MACE). Participants underwent pre-ICIs and repeated multimodality cardiac imaging (echocardiogram, cardiac magnetic resonance (CMR)), serum biomarkers (ultrasensitive troponin I), and rhythm surveillance (ambulatory ECG monitoring) at 6weeks and 6months. Forty-nine patients (38 (77.6%) male; mean age 64.3 (SD 11.0) years old) were included (June 2020-December 2021). Early MACE were observed in 9 (18.4%) patients at mean 40.1 (SD 5.9) days, with heart failure (HF) in 5 (10.2%), ventricular arrhythmias, or new conduction disorders in 4 (8.2%) patients. History of AF (HR 4.49 (CI 1.11-18.14), P = 0.035) predicted early MACE. At 6months follow-up, 18 MACE were observed in 15/49 (31%) patients, with 6 (12.2%) HF events, 5 (10.2%) significant ventricular arrhythmias, or conduction disorders, and 4 (8.2%) AF. There was a significant decline in LVEF (P < 0.001) in patients with no MACE (P = 0.003) or HF (P = 0.0028). Higher creatinine at inclusion (HR 0.99 [0.98-1.00], P = 0.006) predicted HF on multivariate analysis. There were no significant T1 or T2 mapping changes in our study cohort on repeated CMR. Cardiotoxicity on ICIs is more frequent than previously described when using a thorough detection strategy, consisting mainly in HF and asymptomatic rhythm disorders.

Quantitative muscle magnetic resonance imaging in limb-girdle muscular dystrophy type R1 (LGMDR1): A prospective longitudinal cohort study.

Limb-girdle muscular dystrophy (LGMD) type R1 (LGMDR1) is the most common subtype of LGMD in Europe. Prospective longitudinal data, including clinical assessments and new biomarkers such as quantitative magnetic resonance imaging (qMRI), are needed to evaluate the natural course of the disease and therapeutic options. We evaluated eight thigh and seven leg muscles of 13 LGMDR1 patients (seven females, mean age 36.7 years, body mass index 23.9 kg/m2) and 13 healthy age- and gender-matched controls in a prospective longitudinal design over 1 year. Clinical assessment included testing for muscle strength with quick motor function measure (QMFM), gait analysis and patient questionnaires (neuromuscular symptom score, activity limitation [ACTIVLIM]). MRI scans were performed on a 3-T MRI scanner, including a Dixon-based sequence, T2 mapping and diffusion tensor imaging. The qMRI values of fat fraction (FF), water T2 relaxation time (T2), fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity were analysed. Within the clinical outcome measures, significant deterioration between baseline and follow-up was found for ACTIVLIM (p= 0.029), QMFM (p= 0.012). Analysis of qMRI parameters of the patient group revealed differences between time points for both FF and T2 when analysing all muscles (FF: p< 0.001; T2: p= 0.016). The highest increase of fat replacement was found in muscles with an FF of between 10% and 50% at baseline. T2 in muscles with low-fat replacement increased significantly. No significant differences were found for the diffusion metrics. Significant correlations between qMRI metrics and clinical assessments were found at baseline and follow-up, while only T2 changes in thigh muscles correlated with changes in ACTIVLIM over time (ρ = -0.621, p< 0.05). Clinical assessments can show deterioration of the general condition of LGMDR1 patients. qMRI measures can give additional information about underlying pathophysiology. Further research is needed to establish qMRI outcome measures for clinical trials.

Navigator-based motion compensation for liver BOLD measurement with five-echo SAGE EPI and breath-hold task.

The purpose of this work is to apply multi-echo spin- and gradient-echo (SAGE) echo-planar imaging (EPI) combined with a navigator-based (NAV) prospective motion compensation method for a quantitative liver blood oxygen level dependent (BOLD) measurement with a breath-hold (BH) task. A five-echo SAGE sequence was developed to quantitatively measure T2 and T2* to depict function with sufficient signal-to-noise ratio, spatial resolution and sensitivity to BOLD changes induced by the BH task. To account for respiratory motion, a navigator was employed in the form of a single gradient-echo projection readout, located at the diaphragm along the inferior-superior direction. Prior to each transverse imaging slice of the spin-echo EPI-based readouts, navigator acquisition and fat suppression were incorporated. Motion data was obtained from the navigator and transmitted back to the sequence, allowing real-time adjustments to slice positioning. Six healthy volunteers and three patients with liver carcinoma were included in this study. Quantitative T2 and T2* were calculated at each time point of the BH task. Parameters of t value from first-level analysis using a general linear model and hepatovascular reactivity (HVR) of Echo1, T2 and T2* were calculated. The motion caused by respiratory activity was successfully compensated using the navigator signal. The average changes of T2 and T2* during breath-hold were about 1% and 0.7%, respectively. With the help of NAV prospective motion compensation whole liver t values could be obtained without motion artifacts. The quantified liver T2 (34.7 ± 0.7 ms) and T2* (29 ± 1.2 ms) values agreed with values from literature. In healthy volunteers, the distribution of statistical t value and HVR was homogeneous throughout the whole liver. In patients with liver carcinoma, the distribution of t value and HVR was inhomogeneous due to metastases or therapy. This study demonstrates the feasibility of using a NAV prospective motion compensation technique in conjunction with five-echo SAGE EPI for the quantitative measurement of liver BOLD with a BH task.

Interactions of cumulative load with biomarkers of cartilage turnover predict knee cartilage change over 2 years: data from the osteoarthritis initiative.

The purpose was to investigate relationships of cumulative load and cartilage turnover biomarkers with 2-year changes in cartilage in knee osteoarthritis. From participants with Kellgren-Lawrence (KL) grades of 1 to 3, cartilage thickness and transverse relaxation time (T2) were computed from 24-month (baseline) and 48-month magnetic resonance images. Cumulative load was the interaction term of the Physical Activity Scale for the Elderly (PASE) and body mass index (BMI). Serum cartilage oligomeric matrix protein (COMP) and the nitrated form of type II collagen (Coll2-1 NO2) were collected at baseline. Multiple regressions (adjusted for baseline age, KL grade, cartilage measures, pain, comorbidity) evaluated the relationships of cumulative load and biomarkers with 2-year changes. In 406 participants (63.7 (8.7) years), interactions of biomarkers with cumulative load weakly predicted 2-year cartilage changes: (i) COMP × cumulative load explained medial tibia thickness change (R2 increased 0.062 to 0.087, p < 0.001); (ii) Coll2-1 NO2 × cumulative load explained central medial femoral T2 change (R2 increased 0.177 to 0.210, p < 0.001); and (iii) Coll2-1 NO2 × cumulative load explained lateral tibia T2 change (R2 increased 0.166 to 0.188, p < 0.001). Moderate COMP or Coll2-1 NO2 at baseline appeared protective. High COMP or Coll2-1 NO2, particularly with high BMI and low PASE, associated with worsening cartilage. Moderate serum concentrations of cartilage turnover biomarkers, at high and low physical activity, associated with maintained cartilage outcomes over 2 years. In conclusion, high concentrations of cartilage turnover biomarkers, particularly with high BMI and low physical activity, associated with knee cartilage thinning and increasing T2 over 2 years. Key Points • Higher quality cartilage may be better able to tolerate a larger cumulative load than poor quality cartilage. • Among participants enrolled in the Osteoarthritis Initiative Biomarkers Consortium Project, a representation of cumulative load exposure and its interaction with cartilage turnover biomarkers were weakly related with 2-year change in knee cartilage. • These findings suggest that cartilage turnover is a factor that modifies the relationship between loading exposure and cartilage loss in knee OA.

#3063 MRI assessment of skin and muscle sodium (23Na) and fluid volume in haemodialysis patients

Abstract Background and Aims Haemodialysis (HD) is life sustaining for patients with end-stage kidney disease (ESKD). In healthy people, sodium balance is regulated by the kidneys; in ESKD this is achieved by sodium removal during HD. Recent evidence suggests non-osmotically stored sodium in the muscle and/or skin may be a critical factor impacting the development of hypertension and cardiovascular disease (CVD). Sodium (23Na) MRI allows skin and muscle sodium storage assessment and may provide a valuable tool in evaluating sodium storage in dialysis patients. Here, 23Na MRI is used to measure muscle and skin tissue sodium concentration (TSC) in HD participants. HD participants are scanned before and after a single haemodialysis session using 23Na MRI as well as 1H T2 relaxometry to study changes in fluid status. Method Data were collected on HD patients who underwent a pre-HD 23Na MRI calf scan, then had their usual dialysis session with a dialysate sodium of 137 mmol/L, followed by a repeat post-HD 23Na MRI scan. Patient dialysis vintage, residual renal function, and ultrafiltration volume, and blood measures pre- and post-HD were collected. 1H scans were acquired for localisation and muscle segmentation (mDIXON) along with T1 and T2 mapping. 23Na images were acquired for (TSC) quantification. Reference bottles (10, 20, 30 and 40 mmol/L NaCl) were placed above the leg to calibrate TSC muscle and skin maps. Regions-of-interest (ROIs) of each muscle group and the skin were manually segmented on mDIXON scans. In each muscle group the voxel-wise mode (to avoid influence of signals from vessels) of TSC and T2 was estimated. A paired-sample t-test was performed between metrics pre-HD and post-HD. Absolute measures of ΔTSC and ΔT2 were correlated with clinical measures. Results Ten people receiving HD were recruited (age 55-73 yrs, 5 M:5F). Figure 1 shows TSC maps of the HD patients pre-HD and post-HD, with a significant reduction (p &amp;lt; 0.05) in TSC in the extensor, peroneus and gastrocnemius muscles post-HD but skin sodium showed no detectable change. Post-HD TSC significantly positively correlated with post-HD Systolic Blood Pressure (SBP) (P &amp;lt; 0.004) but not with plasma sodium. 1H T2-maps (Fig. 2A) show a significant reduction (p &amp;lt; 0.01) in muscle T2 post-HD compared to pre-HD all muscle groups (Fig. 2B). There were no significant correlations between T2 and 23Na measures, or T2 and clinical measures. There was no significant detectable change in 1H T1. Conclusion Post-HD TSC values are consistent with published data from patients dialysed against a dialysate sodium of 137 mmol/L, and shows a significant correlation of post-HD TSC with post-HD SBP. 1H muscle T2 reduced post-HD, consistent with published data, as patients change from a pre-HD hypervolemia state closer to a post-HD to euvolemia state after fluid removal. There was no correlation of absolute or ΔTSC and 1H T2 and ΔT2 values, suggesting different mechanisms for equilibrium conditions of water and sodium ion concentrations. Future studies will study the effect of dialysate sodium on muscle TSC and mechanistic links to CVD, and include the use of a dedicated skin coil to study skin sodium alongside bioimpedance fluid measures.

How do implants overlying the spine influence “The Law of Diminishing Returns” in early-onset scoliosis patients?

PurposeThe “law of diminishing returns” (LODR) in early-onset scoliosis (EOS) is well-known. We hypothesized that previously observed variations between constructs may be related to the lateral distance that each construct lies from the spine. We therefore sought to determine whether the curve magnitude improvement and spinal length gains for distraction-based constructs in EOS are positively correlated with the collinearity of the spine and the convex-sided implant on posteroanterior radiographs.MethodsA prospectively-collected, multicenter EOS registry was queried for all patients who underwent non-fusion, distraction-based instrumentation surgery. Post-index radiographs were graded from 1 to 5 based on amount of overlap between the convex-sided rod and the apical vertebra. Grade 1: convex rod is lateral to convex-sided pedicle; Grade 2: overlaps the convex-sided pedicle; Grade 3: lies between pedicles; Grade 4: overlaps concave-sided pedicle; Grade 5: medial to concave-sided pedicle. ANOVA assessed the correlations between post-index overlap grade and change in (a) curve magnitude and (b) T1–T12 height. Multivariable regression modeling further assessed these associations.Results284 patients met all selection criteria and were included. On ANOVA, post-index grade was associated with curve magnitude (p <0.001) and T1-12 height (p = 0.028) change. Better curve correction and height change were associated with higher grade. On regression modeling, curve correction (R = 0.574) and T1–T12 height change (R = 0.339) remained significantly associated with grade when controlling for time, anchor locations, age, underlying diagnosis, and pre-index curve magnitude.ConclusionMore apical overlap by the convex rod was associated with better spinal deformity control and improved height gain.Level of Evidence IIITherapeutic.

Ultra-High Contrast MRI: Using Divided Subtracted Inversion Recovery (dSIR) and Divided Echo Subtraction (dES) Sequences to Study the Brain and Musculoskeletal System.

Divided and subtracted MRI is a novel imaging processing technique, where the difference of two images is divided by their sum. When the sequence parameters are chosen properly, this results in images with a high T1 or T2 weighting over a small range of tissues with specific T1 and T2 values. In the T1 domain, we describe the implementation of the divided Subtracted Inversion Recovery Sequence (dSIR), which is used to image very small changes in T1 from normal in white matter. dSIR has shown widespread changes in otherwise normal-appearing white matter in patients suffering from mild traumatic brain injury (mTBI), substance abuse, and ischemic leukoencephalopathy. It can also be targeted to measure small changes in T1 from normal in other tissues. In the T2 domain, we describe the divided echo subtraction (dES) sequence that is used to image musculoskeletal tissues with a very short T2*. These tissues include fascia, tendons, and aponeuroses. In this manuscript, we explain how this contrast is generated, review how these techniques are used in our research, and discuss the current challenges and limitations of this technique.

Physiological and Metabolic Responses to Low-Volume Sprint Interval Exercises: Influence of Sprint Duration and Repetitions.

This study aimed to determine physiological and metabolic responses to two different sprint interval exercises (SIE) matched for total sprint duration and sprint-rest ratio. After having measured peak oxygen uptake (V̇O 2peak ), 14 healthy males (27.1 ± 4.8 yr, 169.6 ± 6.0 cm, 64.5 ± 8.4 kg, V̇O 2peak : 47.2 ± 7.7 mL·kg -1 ·min -1 ) performed four 10-s sprints with 80-s recovery (SIE10) and two 20-s sprints with 160-s recovery (SIE20) on different occasions in a counterbalanced crossover manner. Pulmonary V̇O 2 and changes in tissue oxygenation index (∆TOI) at vastus lateralis (VL) and rectus femoris (RF) were measured during the SIE. Furthermore, T2-weighted magnetic resonance imaging was taken immediately before and after the SIE to determine the activation levels of VL, RF, vastus medialis, vastus intermedius, adductor magnus, biceps femoris long head, semitendinosus, and semimembranosus at 50% of right thigh length. In SIE10, increases in V̇O 2 and ∆TOI at VL and RF plateaued after the second sprint, whereas session-averaged ∆TOI was greater in SIE20 than SIE10 in both muscles (VL: 20.9 ± 7.4 vs 14.2% ± 5.9%, RF: 22.8 ± 9.3 vs 12.9% ± 6.6%, P = 0.00). Although both SIE significantly increased T2 values in all eight muscles, those magnitudes were similar between the conditions (SIE10 vs SIE20: 5%-16% vs 8%-16%). This study showed blunted responses of whole-body (V̇O 2 ) and peripheral (∆TOI) oxidative responses with successive sprints (sprint 1 < sprints 2-4) in SIE10, suggesting that increasing sprint repetitions does not necessarily induce greater oxidative metabolism or stimulus. Moreover, greater peripheral oxygen extraction (∆TOI) was achieved with SIE20, whereas %changes of T2 indicates that the thigh muscles were similarly activated between the SIE conditions.

Quantifying Tendon Degeneration Using Magic Angle Insensitive Ultra-Short Echo Time Magnetization Transfer: A Phantom Study in Bovine Tendons.

The aim of this study was to qualitatively and quantitatively assess changes in bovine flexor tendons before and after collagen degradation and at different angles in relation to the static B 0 field using 3-dimensional ultra-short echo time (UTE) magnetization transfer (MT) imaging within a clinically feasible acquisition time. Eight bovine flexor tendons were examined at 3 T magnetic resonance imaging including 3-dimensional UTE MT and UTE T2* research application sequences (acquired within 4:04 and 6:38 minutes, respectively) before and after enzyme-induced degradation. The tendons were divided into 2 groups: group 1 (controls) treated with phosphate-buffered saline and group 2 treated with collagenase I to induce collagen degeneration. Magnetic resonance imaging was repeated at 0, 27, 55, and 90 degrees to the B 0 field. To calculate quantitative tissue properties, all tendons were semiautomatically segmented, and changes in quantitative UTE T2* and UTE MT ratios (MTRs) were compared at different angles and between groups. In addition to descriptive statistics, the coefficient of variation was calculated to compare UTE MT and UTE T2* imaging. Ultra-short echo time MTR showed a significantly lower coefficient of variation compared with UTE T2* values, indicating a more robust imaging method (UTE MTR 9.64%-11.25%, UTE T2* 18.81%-24.06%, P < 0.001). Both methods showed good performance in detecting degenerated tendons using histopathology as reference standard, with UTE MT imaging having a better area under the curve than UTE T2* mapping (0.918 vs 0.865). Falsely high UTE T2* values were detected at the 55 degrees acquisition angle, whereas UTE MTR values were robust, that is, insensitive to the MAE. Ultra-short echo time MT imaging is a reliable method for quantifying tendon degeneration that is robust to the MAE and can be acquired in a clinically reasonable time.

Sex-and age-related variations in myocardial tissue composition of the healthy heart: a native T1 mapping cohort study.

Cardiovascular diseases manifest differently in males and females, potentially influenced by inherent sex- and age-related differences in myocardial tissue composition. Such inherent differences are not well-established in the literature. With this study using cardiac magnetic resonance (CMR) native T1 mapping, we aim to determine the effect of sex and age on myocardial tissue composition in healthy individuals. CMR native T1 mapping was performed in 276 healthy individuals (55% male, age 8---84 years) on a 1.5 Tesla scanner using a MOLLI 5(3)3 acquisition scheme. Additionally, 30 healthy participants (47% male, age 24-68 years) underwent a 1-year follow-up CMR to assess the longitudinal changes of native T1. Mean native T1 values were 1000 ± 22 ms in males and 1022 ± 23 ms in females [mean difference (MD) = 22 ms, 95% confidence interval (CI) (17, 27)]. Female sex was associated with higher native T1 in multivariable linear regression adjusting for age, heart rate, left ventricular mass index, and blood T1 [β=10 ms, 95% CI (3.4, 15.8)]. There was no significant interaction between sex and age (P = 0.27). Further, age was not associated with native T1 [β=0.1 ms, 95% CI (-0.02, 0.2)], and native T1 did not change during a 1-year period [MD -4 ms, 95% CI (-11, 3)]. Female sex was associated with higher native T1; however, there was no association between age and native T1. Additionally, there was no evidence of an interaction between sex and age. Our findings indicate intrinsic sex-based disparities in myocardial tissue composition.

Changes in Parent-Student Text Message and Phone Call Communication During the Transition to College as Predictors of Cannabis and Simultaneous Use During the First Year.

Parent communication can be protective against cannabis use among young adults. However, changes in parent-student communication frequency naturally occur during the transition from high school to college. Recent research suggests declines in parent-student communication frequency predict increased drinking and consequences during the first year of college, yet these effects on other risky behaviors are unknown. The current study investigated whether post-matriculation changes in frequency of texting/calling with parents predict cannabis use and simultaneous use of cannabis and alcohol, and whether pre-matriculation cannabis and simultaneous use predict changes in communication. First-year students (N = 287, 61.3% female, 50.9% White) reported cannabis and simultaneous use pre- and post-matriculation (T1 & T3) and changes in frequency of texting/calling their mother/father per day (T2). Negative binomial hurdle models examined whether T2 changes in communication frequency predicted T3 cannabis and simultaneous use, and logistic regression models examined whether T1 cannabis and simultaneous use predicted T2 changes in communication frequency. Results revealed that increasing (vs. decreasing) frequency of calling with mothers and texting with fathers was protective against cannabis use, whereas increasing frequency of calling with fathers was associated with greater risk of use. Changes in communication did not significantly predict simultaneous use, nor did pre-matriculation cannabis or simultaneous use predict changes in either mode of communication with parents during the college transition. These findings highlight that changes in mother and father communication may be both beneficial and detrimental to cannabis use depending on the parent and mode of communication. Implications for these findings are discussed.

Is two-staged gamma knife surgery a reasonable management option for very large cerebellar metastases? A case series of three patients.

Two-staged gamma knife surgery (GKS) is a method that may extend the upper tumor volume limit for using GKS in the management of brain metastases. However, the safety of treating very large posterior fossa lesions with this technique has not been well demonstrated. Therefore, we analyzed our experience in treating cerebellar metastases larger than 12 cm3 with two-staged GKS. Four consecutive patients harboring 12 to 30 cm3 cerebellar metastases scheduled two-staged GKS were included in the study, and all but one patient completed the treatment. The treatment doses were 10-13Gy. All patients were followed with regular MR imaging and clinical assessments, and the tumor volumes were measured on all treatment and follow-up images. Tumor progression was not demonstrated in any of the patients. Tumor volumes decreased by, on average, more than half between the two stages. The median survival was 22months, and no patient died due to intracranial tumor progression. Peritumoral edema at the first GKS resolved in all patients, replaced by asymptomatic mild T2 changes in two of them not requiring any treatment. No radiation-induced complication has developed thus far. Staged GKS seems to be a feasible management option for very large cerebellar metastases.

Effect of inhaled oxygen level on dynamic glucose-enhanced MRI in mouse brain.

To investigate the effect of inhaled oxygen level on dynamic glucose enhanced (DGE) MRI in mouse brain tissue and CSF at 3 T. DGE data of brain tissue and CSF from mice under normoxia or hyperoxia were acquired in independent and interleaved experiments using on-resonance variable delay multi-pulse (onVDMP) MRI. A bolus of 0.15 mL filtered 50% D-glucose was injected through the tail vein over 1 min during DGE acquisition. MRS was acquired before and after DGE experiments to confirm the presence of D-glucose. A significantly higher DGE effect under normoxia than under hyperoxia was observed in brain tissue (p = 0.0001 and p = 0.0002 for independent and interleaved experiments, respectively), but not in CSF (p > 0.3). This difference is attributed to the increased baseline MR tissue signal under hyperoxia induced by a shortened T1 and an increased BOLD effect. When switching from hyperoxia to normoxia without glucose injection, a signal change of ˜3.0% was found in brain tissue and a signal change of ˜1.5% was found in CSF. DGE signal was significantly lower under hyperoxia than that under normoxia in brain tissue, but not in CSF. The reason is that DGE effect size of brain tissue is affected by the baseline signal, which could be influenced by T1 change and BOLD effect. Therefore, DGE experiments in which the oxygenation level is changed from baseline need to be interpreted carefully.

The Performance of Pulmonary Function Tests in Predicting Systemic Sclerosis—Interstitial Lung Disease in the European Scleroderma Trial and Research Database

Background and Objectives: In SSc, ILD is a major cause of morbidity and mortality. We aimed to investigate the performance of DLCO (diffusing capacity of lung carbon monoxide) and FVC (forced vital capacity) delta change (Δ) and baseline values in predicting the development of SSc-ILD. Methods: Longitudinal data of DLCO, FVC, and ILD on the HRCT of SSc patients from the EUSTAR database were evaluated at baseline (t0) and after 12 (±4) (t1) and 24 (±4) (t2) months. Results: 474/17805 patients were eligible for the study (403 females); 46 (9.7%) developed ILD at t2. Positivity for anti-topoisomerase antibodies (117 patients) showed an association with ILD development at t2 (p = 0.0031). Neither the mean t0 to t1 change (Δ) of DLCO nor the mean t0 to t1 FVCΔ predicted the appearance of ILD at t2. Investigating the possible role of baseline DLCO and FVC values in predicting ILD appearance after 24 (±4) months, we observed a moderate predictive capability of t0 DLCO &lt; 80%, stronger than that of FVC &lt; 80%. Conclusions: We suggest that an impaired baseline DLCO may be predictive of the appearance of ILD after 2 years of follow-up. This result advances the hypothesis that a reduction in gas exchange may be considered an early sign of lung involvement. However, further rigorous studies are warranted to understand the predictive role of DLCO evaluation in the course of SSc.

Retrospectively gated ultrashort-echo-time MRI T1 mapping reveals compromised pulmonary microvascular NO-dependent function in a murine model of acute lung injury.

This study sought to develop noninvasive, in vivo imaging schemes that allow for quantitative assessment of pulmonary microvascular functional status based on the combination of pulmonary T1 mapping and dynamic contrast-enhanced (DynCE) imaging. Ultrashort-echo-time (UTE) imaging at 9.4 T of lung parenchyma was performed. Retrospective gating was based on modulation of the first point in each recorded spoke. T1 maps were obtained using a series of five consecutive images with varying RF angles and analyzed with the variable flip angle approach. The obtained mean T1 lung value of 1078 ± 38 ms correlated well with previous reports. Improved intersession variability was observed, as evident from a decreased standard deviation of motion-resolved T1 mapping (F-test = 0.051). Animals received lipopolysaccharide (LPS) and were imaged at t= 2, 6, and 12 h after administration. The nitric oxide (NO)-dependent function was assessed according to changes in lung T1 after L-NAME injection, while microvascular perfusion and oxidant stress were assessed with contrast-enhanced imaging after injection of gadolinium or 3-carbamoyl-proxyl nitroxide radical, respectively. Retrospectivel gated UTE allowed robust, motion-compensated imaging that could be used for T1 mapping of lung parenchyma. Changes in lung T1 after L-NAME injection indicated that LPS induced overproduction of NO at t= 2 and 6 h after LPS, but NO-dependent microvascular function was impaired at t= 12 h after LPS. DynCE imaging at t= 6 h after LPS injection revealed decreased microvascular perfusion, with increased vascular permeability and oxidant stress. MRI allows to visualize and quantify lung microvascular NO-dependent function and its concomitant impairment during acute respiratory distress syndrome development with high sensitivity. UTE T1 mapping appears to be sensitive and useful in probing pulmonary microvascular functional status.

Longitudinal prospective comparison of pancreatic iron by magnetic resonance in thalassemia patients transfusion-dependent since early childhood treated with combination deferiprone-desferrioxamine vs deferiprone or deferasirox monotherapy.

In transfusion-dependent thalassemia patients who started regular transfusions in early childhood, we prospectively and longitudinally evaluated the efficacy on pancreatic iron of a combined deferiprone (DFP) + desferrioxamine (DFO) regimen versus either oral iron chelator as monotherapy over a follow-up of 18 months. We selected patients consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia network who received a combined regimen of DFO+DFP (No.=28) or DFP (No.=61) or deferasirox (DFX) (No.=159) monotherapy between the two magnetic resonance imaging scans. Pancreatic iron overload was quantified by the T2* technique. At baseline no patient in the combined treatment group had a normal global pancreas T2* (≥26 ms). At follow-up the percentage of patients who maintained a normal pancreas T2* was comparable between the DFP and DFX groups (57.1 vs 70%; p=0.517).Among the patients with pancreatic iron overload at baseline, global pancreatic T2* values were significantly lower in the combined DFO+DFP group than in the DFP or DFX groups. Since changes in global pancreas T2* values were negatively correlated with baseline pancreas T2* values, the percent changes in global pancreas T2* values, normalized for the baseline values, were considered. The percent changes in global pancreas T2* values were significantly higher in the combined DFO+DFP group than in either the DFP (p=0.036) or DFX (p=0.030) groups. In transfusion-dependent patients who started regular transfusions in early childhood, combined DFP+DFO was significantly more effective in reducing pancreatic iron than was either DFP or DFX.

NMR analysis of structural geometry and molecular dynamics in perovskite-type N(CH3)4CdBr3 crystal near high-temperature phase transition.

The NMR chemical shifts, linewidths, spin-lattice relaxation times in the rotating system T1ρ, and spin-lattice relaxation times in the laboratory system T1 were evaluated for the perovskite-type N(CH3)4CdBr3 crystal, aiming to understand the changes in the structural geometry and molecular dynamics from phase I to phase II. From the temperature-dependence of the 1H, 13C, 14N, and 113Cd NMR chemical shifts, the structural geometry underwent a continuous change, without anomalous changes around (TC = 390 K). However, the linewidths in phase I were narrower than those in phase II, indicating that the motional averaging effects were caused by the rapid rotation of the N(CH3)4 group. Sudden changes in T1 and T1ρ were observed near TC, for which the activation energy Ea in phase I was approximately 12 times larger than that in phase II; the small Ea values in phase II indicate a large degree of freedom for the methyl group and CdBr6 octahedra, whereas the large Ea in phase I was primarily attributed to the overall N(CH3)4 and the 113Cd in the CdBr6 groups. Consequently, the phase transition mechanisms of N(CH3)4CdBr3 are related to reorientation of the N(CH3)4 group and the arrangement of the CdBr6 groups.