Actigraphy measures show sleep improvement after parathyroidectomy for primary hyperparathyroidism.

IMPORTANCE: The symptoms of primary hyperparathyroidism are often subtle, such as fatigue, mood changes, and sleep disturbances. After parathyroidectomy, patients often report improvement in sleep and mood; however, objective data supporting these improvements is lacking. OBJECTIVE: This prospective study uses standard measures to objectively and subjectively assess sleep in patients with primary hyperparathyroidism before and after parathyroidectomy. DESIGN: A longitudinal prospective study was conducted over three one-week-long periods: pre-parathyroidectomy, 1-week post-parathyroidectomy, and three months post-parathyroidectomy. During each time point, patients wore an actigraphy device, recorded a sleep diary, and completed the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Depression Anxiety Stress Scale (DASS). Statistical analysis was performed using repeated measures models to compare the average measures among the three time points and test for trends over time. SETTING: Single institution, tertiary care center. PARTICIPANTS: Patients with primary hyperparathyroidism from ages 18 to 89 years old. EXPOSURE: Parathyroidectomy between September 2020 and January 2024. MAIN OUTCOMES AND MEASURES: Actigraphy data, consensus sleep diary, Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Depression Anxiety Stress Scales - 21 Items (DASS). RESULTS: Thirty-six patients were enrolled, and 34 patients completed the study. Actigraphy data showed a significant negative trend in average sleep latency (p = 0.045) and average time in bed (p = 0.046). Sleep diary data showed additional differences in the number of awakenings (p = 0.002), wake after sleep onset (p < 0.001), sleep quality (p < 0.001), and sleep efficiency (p = 0.02) among the three time points and/or as a significant negative trend. PSQI and ISI scores were significantly different among the three time points (p = 0.002 and p < 0.001, respectively) and also declined significantly over time (p = 0.008 and p = 0.007, respectively). DASS depression, anxiety, and stress scores were significantly different among the three time points (p < 0.001, p = 0.01, and p < 0.001, respectively), and stress also declined significantly over time (p = 0.005). CONCLUSION AND RELEVANCE: This study represents the most extensive prospective study demonstrating objective and subjective sleep and mood improvement in patients with primary hyperparathyroidism after parathyroidectomy.

1H and 31P magnetic resonance spectroscopy reveals potential pathogenic and biomarker metabolite alterations in Lafora disease.

Lafora disease is a fatal teenage-onset progressive myoclonus epilepsy and neurodegenerative disease associated with polyglucosan bodies. Polyglucosans are long-branched and as a result precipitation- and aggregation-prone glycogen. In mouse models, downregulation of glycogen synthase, the enzyme that elongates glycogen branches, prevents polyglucosan formation and rescues Lafora disease. Mouse work, however, has not yet revealed the mechanisms of polyglucosan generation, and few in vivo human studies have been performed. Here, non-invasive in vivo magnetic resonance spectroscopy (1H and 31P) was applied to test scan feasibility and assess neurotransmitter balance and energy metabolism in Lafora disease towards a better understanding of pathogenesis. Macromolecule-suppressed gamma-aminobutyric acid (GABA)-edited 1H magnetic resonance spectroscopy and 31P magnetic resonance spectroscopy at 3 and 7 tesla, respectively, were performed in 4 Lafora disease patients and a total of 21 healthy controls (12 for the 1H magnetic resonance spectroscopy and 9 for the 31PMRS). Spectra were processed using in-house software and fit to extract metabolite concentrations. From the 1H spectra, we found 33% lower GABA concentrations (P = 0.013), 34% higher glutamate + glutamine concentrations (P = 0.011) and 24% lower N-acetylaspartate concentrations (P = 0.0043) in Lafora disease patients compared with controls. From the 31P spectra, we found 34% higher phosphoethanolamine concentrations (P = 0.016), 23% lower nicotinamide adenine dinucleotide concentrations (P = 0.003), 50% higher uridine diphosphate glucose concentrations (P = 0.004) and 225% higher glucose 6-phosphate concentrations in Lafora disease patients versus controls (P = 0.004). Uridine diphosphate glucose is the substrate of glycogen synthase, and glucose 6-phosphate is its extremely potent allosteric activator. The observed elevated uridine diphosphate glucose and glucose 6-phosphate levels are expected to hyperactivate glycogen synthase and may underlie the generation of polyglucosans in Lafora disease. The increased glutamate + glutamine and reduced GABA indicate altered neurotransmission and energy metabolism, which may contribute to the disease's intractable epilepsy. These results suggest a possible basis of polyglucosan formation and potential contributions to the epilepsy of Lafora disease. If confirmed in larger human and animal model studies, measurements of the dysregulated metabolites by magnetic resonance spectroscopy could be developed into non-invasive biomarkers for clinical trials.

Cutaneous Hydrophilic Polymer Embolism: An Important and Overlooked Clinical Entity.

ABSTRACT: Hydrophilic polymer embolism from vascular medical devices is an underrecognized clinical entity that can cause deleterious end-organ ischemia and culminate in mortality. This is concerning as we are in the era where minimally invasive procedures are commonplace. Diagnosis is often made retrospectively after obtaining histopathological tissue samples showing endoluminal, cerebriform, amorphous, anucleate, basophilic, nonrefractile, nonpolarizable foreign body material. We detail 2 more cases of cutaneous hydrophilic polymer embolism to underscore its salient clinicopathological features and increase awareness of this important iatrogenic entity.

Oncologic Safety of Close Margins in Patients With Low- to Intermediate-Grade Major Salivary Gland Carcinoma.

Importance: Postoperative radiation therapy for close surgical margins in low- to intermediate-grade salivary carcinomas lacks multi-institutional supportive evidence. Objective: To evaluate the oncologic outcomes for low- and intermediate-grade salivary carcinomas with close and positive margins. Design, Setting, and Participants: The American Head and Neck Society Salivary Gland Section conducted a retrospective cohort study from 2010 to 2019 at 41 centers. Margins were classified as R0 (negative), R1 (microscopically positive), or R2 (macroscopically positive). R0 margins were subclassified into clear (>1 mm) or close (≤1 mm). Data analysis was performed from June to October 2023. Main Outcomes and Measures: Main outcomes were risk factors for local recurrence. Results: A total of 865 patients (median [IQR] age at surgery, 56 [43-66] years; 553 female individuals [64%] and 312 male individuals [36%]) were included. Of these, 801 (93%) had parotid carcinoma and 64 (7%) had submandibular gland carcinoma, and 748 (86%) had low-grade tumors and 117 (14%) had intermediate-grade tumors, with the following surgical margins: R0 in 673 (78%), R1 in 168 (19%), and R2 in 24 (3%). Close margins were found in 395 of 499 patients with R0 margins (79%), for whom margin distances were measured. A total of 305 patients (35%) underwent postoperative radiation therapy. Of all 865 patients, 35 (4%) had local recurrence with a median (IQR) follow-up of 35.3 (13.9-59.1) months. In patients with close margins as the sole risk factor for recurrence, the local recurrence rates were similar between those who underwent postoperative radiation therapy (0 of 46) or observation (4 of 165 [2%]). Patients with clear margins (n = 104) had no recurrences. The local recurrence rate in patients with R1 or R2 margins was better in those irradiated (2 of 128 [2%]) compared to observed (13 of 64 [20%]) (hazard ratio [HR], 0.05; 95% CI, 0.01-0.24). Multivariable analysis for local recurrence found the following independent factors: age at diagnosis (HR for a 10-year increase in age, 1.33; 95% CI, 1.06-1.67), R1 vs R0 (HR, 5.21; 95% CI, 2.58-10.54), lymphovascular invasion (HR, 4.47; 95% CI, 1.43-13.99), and postoperative radiation therapy (HR, 0.10; 95% CI, 0.04-0.29). The 3-year local recurrence-free survivals for the study population were 96% vs 97% in the close margin group. Conclusions and Relevance: In this cohort study of patients with low- and intermediate-grade major salivary gland carcinoma, postoperative radiation therapy for positive margins was associated with decreased risk of local recurrence. In isolation from other risk factors for local recurrence, select patients with close surgical margins (≤1 mm) may safely be considered for observation.

Elucidating survival and functional outcomes in patients with primary head and neck malignancies treated in academic versus community settings.

BACKGROUND: Differences in treatment outcomes between community or academic centers are incompletely understood. METHODS: Retrospective review of head and neck cancer patients between 2010 and 2020 in a rural health region. Kaplan-Meier curves and log-rank tests were used to evaluate survival outcomes, along with bivariate and multivariable Cox proportional hazards models. Linear regression was used for functional outcomes of tracheotomy and gastrostomy tube dependence. RESULTS: Two hundred and forty-eight patients treated at an academic center were compared with 94 patients treated in community centers. In multivariable analysis, the risk of death (HR = 0.60, p = 0.019), and risk of recurrence were lower (HR = 0.29, p < 0.001) for patients treated in academic centers. Patients treated in community centers had longer gastrostomy tube dependence (p = 0.002). CONCLUSION: Our findings suggest that treatment at an academic center was associated with a lower risk of recurrence and shorter gastrostomy tube dependence compared to treatment in the community.

Postoperative Urinary Complications in Head and Neck Free Flap Reconstructive Surgery.

OBJECTIVE: The purpose of this study is to evaluate the postoperative urinary complications and the optimal timing of foley catheter removal in patients who underwent free flap reconstructive surgery for head and neck pathology. METHODS: A retrospective case-control study of head and neck patients who underwent free flap reconstructive surgery at a single institution between January 2009 and December 2021 was conducted. Patient risk factors for postoperative urinary retention (POUR) were analyzed. Fisher Exact and Wilcoxon Rank Sum tests were used to evaluate rates of foley replacement, straight catheterization, and catheter-associated urinary tract infection (CAUTI) and associated risk factors. RESULTS: Two hundred and eleven patients were included in this study. Older age, lower BMI, lower intraoperative fluid volumes, and need for straight catheterization were statistically significant for POUR requiring foley replacement. Shorter total (P = .04) and postoperative (P = .01) foley duration showed statistical significance for POUR requiring straight catheterization. About 60% of patients who had straight catheterization required a foley replacement (P < .001). Only one patient (0.5%) developed a urinary tract infection (UTI). CONCLUSION: Foley catheter duration impacts the risk of POUR requiring straight catheterization and subsequently, foley replacement. Optimal timing for foley catheter removal in the postoperative period remains to be elucidated. Removal of catheters between 21 and 48 hours after surgery may decrease the risk of POUR without increasing the rate of CAUTI in patients with head and neck pathology undergoing free flap reconstructive surgery.

Metabolic profile of complete spinal cord injury in pons and cerebellum: A 3T 1H MRS study.

The aim of this exploratory study was the assessment of the metabolic profiles of persons with complete spinal cord injury (SCI) in three region-of-interests (pons, cerebellar vermis, and cerebellar hemisphere), with magnetic resonance spectroscopy, and their correlations to clinical scores. Group differences and association between metabolic and clinical scores were examined. Fifteen people with chronic SCI (cSCI), five people with subacute SCI (sSCI) and fourteen healthy controls were included. Group comparison between cSCI and HC showed lower total N-acetyl-aspartate (tNAA) in the pons (p = 0.04) and higher glutathione (GSH) in the cerebellar vermis (p = 0.02). Choline levels in the cerebellar hemisphere were different between cSCI and HC (p = 0.02) and sSCI and HC (p = 0.02). A correlation was reported for choline containing compounds (tCho) to clinical scores in the pons (rho = - 0.55, p = 0.01). tNAA to total creatine (tNAA/tCr ratio) correlated to clinical scores in the cerebellar vermis (rho = 0.61, p = 0.004) and GSH correlated to the independence score in the cerebellar hemisphere (rho = 0.56, p = 0.01). The correlation of tNAA, tCr, tCho and GSH to clinical scores might be indicators on how well the CNS copes with the post-traumatic remodeling and might be further examined as outcome markers.

Effectiveness of smoking cessation interventions among persons with cancer: A systematic review.

OBJECTIVES: Continued smoking after cancer diagnosis is associated with worse outcomes, however, many persons diagnosed with cancer who smoke are unable to quit successfully. Effective interventions are needed to promote quitting in this population. The purpose of this systematic review is to understand the most effective interventions for smoking cessation among persons with cancer and to identify gaps in knowledge and methodology to suggest directions for future research. METHODS: Three electronic databases (The Cochrane Central Register of Controlled trials, MEDLINE, and EMBASE) were searched for studies of smoking cessation interventions among persons with cancer, published up to 1 July 2021. Title and abstract screening, full-text review, and data extraction was completed by two independent reviewers, via Covalence software, with any discordance resolved by a third reviewer. A quality assessment was completed using the Cochrane Risk of Bias Tool Version 2. RESULTS: Thirty-six articles were included in the review, including 17 randomized-controlled trials (RCTs) and 19 non-RCT studies. Of the 36 studies, 28 (77.8%) utilized an intervention that included both counseling and medication, with 24 (85.7%) providing medication to participants at no cost. Abstinence rates in the RCT intervention groups (n = 17) ranged from 5.2% to 75%, while the non-RCTs found abstinence rates ranging from 15% to 46%. Overall, studies met a mean of 2.28 out of seven quality items, ranging from 0 to 6. CONCLUSIONS: Our study highlights the importance of utilizing intensive combined behavioral and pharmacological interventions for persons with cancer. While combined therapy interventions seem to be the most effective, more research is needed, as current studies have several quality issues, including the lack of biochemical verification for abstinence.

Distribution and Clinical Characteristics of Periorbital Infantile Hemangiomas.

Background: Periorbital infantile hemangiomas (POIHs) are associated with a high incidence of visual complications. Objective(s): To analyze the sites of predilection of POIHs and to determine whether certain sites require earlier intervention due to their higher rate of visual complications. Methods: A retrospective case series study was conducted on patients from two tertiary care centers for 25 years. The location of POIHs was determined from clinical photographs, medical records, and radiological studies. The presence or absence of anisometropic astigmatism (anisoastigmatism) and amblyopia was recorded. Data were analyzed using a chi-square test. Results: There were 486 patients, of which 302 patients had ophthalmology evaluations and 245 patients had refractive error data. At presentation, 10% of patients already had amblyopia and 44% had anisoastigmatism. Medial eyelid lesions had the highest risk of developing anisoastigmatism (anisoastigmatism correlates with eyelid position, p = 0.0001). Segmental and upper medial lesions had the highest risk of amblyopia at initial evaluation. Conclusion: The site of POIH is an important indicator for developing clinically significant anisoastigmatism and amblyopia, underlining the need for early ophthalmologic assessment and management.

Improved signal-to-noise performance of MultiNet GRAPPA 1 H FID MRSI reconstruction with semi-synthetic calibration data.

PURPOSE: To further develop MultiNet GRAPPA, a neural-network-based reconstruction, for lower SNR proton MRSI (1 H MRSI) data using adapted undersampling schemes and improved training sets. METHODS: 1 H FID-MRSI data and an anatomical image for GRAPPA reconstruction were acquired in two slices in the human brain (n = 6) at 7T. MRSI data were retrospectively undersampled for a 4×, 6×, and 7× acceleration rate. Signal-to-noise, relative error (RE) between accelerated and fully sampled metabolic maps, RMS of the lipid artifacts, and fitting reliability were compared across acceleration rates, to the fully sampled data, and with different kinds and amounts of training images. RESULTS: Training with semi-synthetic images resulted in higher SNR and lower lipid RMS relative to training with acquired images from one or several subjects. SNR increased with the number of semi-synthetic training images and the 4× accelerated data retains ∼30% more SNR than other accelerated data. Spectra reconstructed with 20 semi-synthetic averages retained ∼100% more SNR and had ∼5% lower lipid RMS than those reconstructed with the center k-space points of one image as was originally proposed for very high SNR MRSI data and had higher fitting reliability. The metabolite RE was lowest when training with 20-semi-synthetic training images and highest when training with the center k-space points of one image. CONCLUSION: MultiNet GRAPPA is feasible with lower SNR 1 H MRSI data if 20-semi-synthetic training images are used at a 4× acceleration rate. This acceleration rate provided the best trade-off between scan time and spectral SNR.

Sensorimotor Cortex GABA Moderates the Relationship between Physical Exertion and Assessments of Effort.

Experiences of physical exertion guide our assessments of effort. While these assessments critically influence our decisions to engage in daily activities, little is known about how they are generated. We had female and male human participants exert grip force and assess how effortful these exertions felt; and used magnetic resonance spectroscopy to measure their brain GABA concentration. We found that variability in exertion (i.e., the coefficient of variation in their force exertion profile) was associated with increases in assessments of effort, making participants judge efforts as more costly. GABA levels in the sensorimotor cortex (SM1) moderated the influence of exertion variability on overassessments of effort. In individuals with higher sensorimotor GABA, exertion variability had a diminished influence on overassessments of effort. Essentially, sensorimotor GABA had a protective effect on the influence of exertion variability on inflations of effort assessment. Our findings provide a neurobiological account of how the brain's GABAergic system integrates features of physical exertion into judgments of effort, and how basic sensorimotor properties may influence higher-order judgments of effort.SIGNIFICANCE STATEMENT Feelings of effort critically shape our decisions to partake in activities of daily living. It remains unclear how the brain translates physical activity into judgments about effort (i.e., "How effortful did that activity feel?"). Using modeling of behavior and neuroimaging, we show how the nervous system uses information about physical exertion to generate assessments of effort. We found that higher variability in exertion was associated with increases in assessments of effort, making participants judge efforts as more costly. GABA, the brain's main inhibitory neurotransmitter, moderated the influence of exertion variability on overassessments of effort. These findings illustrate how low-level features of motor performance and sensorimotor neurochemistry influence higher-order cognitive processes related to feelings of effort.

Phrenic nerve schwannoma presenting as an asymptomatic neck mass.

Phrenic nerve schwannomas of the head and neck are exceedingly rare pathologies that can present as an asymptomatic neck mass. Surgery is the definitive treatment, and a conservative surgical approach is preferred if a benign pathology is suspected.

Multimodal Imaging and Visual Evoked Potentials Reveal Key Structural and Functional Features That Distinguish Symptomatic From Presymptomatic Huntington's Disease Brain.

BACKGROUND: Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by motor, cognitive, and psychiatric abnormalities. Currently, matched analyses of structural and functional differences in the brain from the same study cohort and, specifically, in HD patients from an ethnically diverse Indian population are lacking. Such findings aid in identifying noninvasive and sensitive imaging biomarkers. OBJECTIVE: The aim of the study was to understand the structural and functional differences between HD and control brain, and presymptomatic and symptomatic HD brain in the Indian population. MATERIALS AND METHODS: Seventeen HD (11 symptomatic HD [S-HD] and six presymptomatic HD [P-HD], with comparable CAG repeats), and 12 healthy controls were examined. Macrostructural (volume), microstructural (diffusivity), and functional (neurochemical levels and glucose metabolism) imaging of the brain was done along with the determination of visual latencies. RESULTS: HD brain showed increased intercaudate distance; significant subcortical volumetric loss; reduced fractional anisotropy; increased mean, axial, and radial diffusivity; lower levels of total N-acetyl aspartate; elevated total choline levels; and reduced glucose metabolism compared with control brain. Interestingly, compared with P-HD, S-HD patients demonstrated a strong inverse correlation between age at onset and CAG repeat length, and prolonged P100 latency. In addition, caudate and putamen in S-HD brain showed significant volumetric loss and increased diffusivity compared with P-HD brain. CONCLUSIONS: HD brain showed distinct macrostructural, microstructural, and functional differences compared with control brain in the Indian population. Interestingly, patients with S-HD had a significant volumetric loss, increased diffusivity, altered neurochemical profile, and delayed P100 latency compared with P-HD patients. Examining these alterations clinically could aid in monitoring the progression of HD.

Improved prospective frequency correction for macromolecule-suppressed GABA editing with metabolite cycling at 3T.

PURPOSE: To combine metabolite cycling with J-difference editing (MC MEGA) to allow for prospective frequency correction at each transient without additional acquisitions and compare it to water-suppressed MEGA-PRESS (WS MEGA) editing with intermittent prospective frequency correction. METHODS: Macromolecule-suppressed gamma aminobutyric acid (GABA)-edited experiments were performed in a phantom and in the occipital lobe (OCC) (n = 12) and medial prefrontal cortex (mPFC) (n = 8) of the human brain. Water frequency consistency and average offset over acquisition time were compared. GABA multiplet patterns, signal intensities, and choline subtraction artifacts were evaluated. In vivo GABA concentrations were compared and related to frequency offset in the OCC. RESULTS: MC MEGA was more stable with 21% and 32% smaller water frequency SDs in the OCC and mPFC, respectively. MC MEGA also had 39% and 40% smaller average frequency offsets in the OCC and mPFC, respectively. Phantom GABA multiplet patterns and signal intensities were similar. In vivo GABA concentrations were smaller in MC MEGA than in WS MEGA, with median (interquartile range) of 2.52 (0.27) and 2.29 (0.19) institutional units (i.u.), respectively in the OCC scans without prior DTI, and 0.99 (0.3) and 1.72 (0.5), respectively in the mPFC. OCC WS MEGA GABA concentrations, but not MC MEGA GABA concentrations were moderately correlated with frequency offset. mPFC WS MEGA spectra contained significantly more subtraction artifacts than MC MEGA spectra. CONCLUSION: MC MEGA is feasible and allows for prospective frequency correction at every transient. MC MEGA GABA concentrations were not biased by frequency offsets and contained less subtraction artifacts compared to WS MEGA.

Hippocampal and striatal responses during motor learning are modulated by prefrontal cortex stimulation.

While it is widely accepted that motor sequence learning (MSL) is supported by a prefrontal-mediated interaction between hippocampal and striatal networks, it remains unknown whether the functional responses of these networks can be modulated in humans with targeted experimental interventions. The present proof-of-concept study employed a multimodal neuroimaging approach, including functional magnetic resonance (MR) imaging and MR spectroscopy, to investigate whether individually-tailored theta-burst stimulation of the dorsolateral prefrontal cortex can modulate responses in the hippocampus and the basal ganglia during motor learning. Our results indicate that while stimulation did not modulate motor performance nor task-related brain activity, it influenced connectivity patterns within hippocampo-frontal and striatal networks. Stimulation also altered the relationship between the levels of gamma-aminobutyric acid (GABA) in the stimulated prefrontal cortex and learning-related changes in both activity and connectivity in fronto-striato-hippocampal networks. This study provides the first experimental evidence, to the best of our knowledge, that brain stimulation can alter motor learning-related functional responses in the striatum and hippocampus.

Organocatalytic Approach to Photochemical Lignin Fragmentation.

Herein, an organocatalytic method for photochemical C-O bond cleavage of lignin systems is reported. The use of photochemistry enabled fragmentation of the ß-O-4 linkage, the primary linkage in lignin, provides the fragmentation products in good to high yields. The approach was merged with reported oxidation conditions in a one-pot, two-step platform without any intermediary purification, suggesting its high fidelity. The future utility of the organocatalytic method was illustrated by applying the visible light-mediated protocol to continuous flow processing.

Comparison of Multivendor Single-Voxel MR Spectroscopy Data Acquired in Healthy Brain at 26 Sites.

Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better understand sources of the total variance in quantified metabolite levels. Purpose To compare multisite quantitative brain MR spectroscopy data acquired in healthy participants at 26 sites by using the vendor-supplied single-voxel point-resolved spectroscopy (PRESS) sequence. Materials and Methods An MR spectroscopy protocol to acquire short-echo-time PRESS data from the midparietal region of the brain was disseminated to 26 research sites operating 3.0-T MR scanners from three different vendors. In this prospective study, healthy participants were scanned between July 2016 and December 2017. Data were analyzed by using software with simulated basis sets customized for each vendor implementation. The proportion of total variance attributed to vendor-, site-, and participant-related effects was estimated by using a linear mixed-effects model. P values were derived through parametric bootstrapping of the linear mixed-effects models (denoted Pboot). Results In total, 296 participants (mean age, 26 years ± 4.6; 155 women and 141 men) were scanned. Good-quality data were recorded from all sites, as evidenced by a consistent linewidth of N-acetylaspartate (range, 4.4-5.0 Hz), signal-to-noise ratio (range, 174-289), and low Cramér-Rao lower bounds (≤5%) for all of the major metabolites. Among the major metabolites, no vendor effects were found for levels of myo-inositol (Pboot > .90), N-acetylaspartate and N-acetylaspartylglutamate (Pboot = .13), or glutamate and glutamine (Pboot = .11). Among the smaller resonances, no vendor effects were found for ascorbate (Pboot = .08), aspartate (Pboot > .90), glutathione (Pboot > .90), or lactate (Pboot = .28). Conclusion Multisite multivendor single-voxel MR spectroscopy studies performed at 3.0 T can yield results that are coherent across vendors, provided that vendor differences in pulse sequence implementation are accounted for in data analysis. However, the site-related effects on variability were more profound and suggest the need for further standardization of spectroscopic protocols. © RSNA, 2020 Online supplemental material is available for this article.

Retrospective motion compensation for edited MR spectroscopic imaging.

Edited magnetic resonance spectroscopic imaging (MRSI) is capable of mapping the distribution of low concentration metabolites such as gamma-aminobutyric acid (GABA) or and glutathione (GSH), but is prone to subtraction artifacts due to head motion or other instabilities. In this study, a retrospective motion compensation algorithm for edited MRSI is proposed. The algorithm identifies movement-affected signals by comparing residual water and lipid peaks between different transients recorded at the same point in k-space, and either phase corrects, replaces or removes affected spectra prior to spatial Fourier transformation. The method was tested on macromolecule-unsuppressed GABA-edited spin-echo MR spectroscopic imaging data acquired from 8 healthy adults scanned at 3T. Relative to non-motion compensated data sets, the motion compensated data had significantly less subtraction artifacts across subjects. The residual choline (Cho) peak in the spectrum (which is well resolved from as a different chemical shift from GABA and is completely absent in a spectrum without subtraction artifact) was used as a metric of motion artifact severity. The normalized Cho area was 5.14 times lower with motion compensation than without motion compensation. A 'removal-only' version of the technique is also shown to be promising in removing motion-corrupted artifacts in a GSH-edited MRSI acquisition acquired in 1 healthy subject. This study introduces a motion compensation technique and demonstrates that retrospective compensation in k-space is possible and significantly reduces the amount of subtraction artifacts in the resulting edited spectra.

Autologous Fat Grafting Restores Soft-tissue Contour Deformities after Vascular Anomaly Surgery.

BACKGROUND: Soft-tissue loss is expected after resection of large vascular lesions. Autologous fat transfer improves asymmetries; however, systematic outcomes are not previously described for vascular anomaly reconstruction. METHODS: Retrospective chart review from 2012 to 2015 included patients receiving autologous fat transfers for soft-tissue defects during or following vascular anomaly surgery at a tertiary care center. Patients received dermal en bloc fat grafts, lipoaspirates, or both. Pre- and postoperative photographs were blindly reviewed by 3 facial plastic surgeons using a 5-point scale. Dermal abdominal en bloc fat grafts were placed immediately after excision of a vascular anomaly. Lipoaspirate fat grafting was performed using liposuction (modified Coleman technique) and centrifugation. The effectiveness of fat transfers was assessed using patients' photographs. Final follow-up was 6 months to 5 years. RESULTS: There were 35 autologous fat transfer surgeries in 27 patients. Fourteen patients received en bloc dermal fat grafts (14 total), 13 lipoaspirate transfers (21 total), and 3 both. Ages ranged from 2 to 69 years (mean = 25 years). Majority of patients (81%) had head and neck lesions. Average volume of fat injected was 16.5 mL (range 0.8-100 mL). The average observer rating score was 2.45 [1-5 (5-point scale)] in the en bloc fat graft group versus 3.83 in the lipoaspirate group (P < 0.0001) with acceptable inter-rater reliability between 3 observers (coefficient of concordance = 0.76). Follow-up ranged from 6 months to 5 years. There were 2 complications in the dermal fat graft group and none in the lipoaspirate group. CONCLUSIONS: Autologous fat transfer improves symmetry and scarring after surgical treatment of vascular anomalies. Fat grafting is permanent and reliable and creates a more symmetric soft-tissue contour compared with dermal fat grafts.

Big GABA II: Water-referenced edited MR spectroscopy at 25 research sites.

Accurate and reliable quantification of brain metabolites measured in vivo using 1H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological challenge. In this study, spectrally edited γ-aminobutyric acid (GABA) MRS data were analyzed and GABA levels were quantified relative to an internal tissue water reference. Data from 284 volunteers scanned across 25 research sites were collected using GABA+ (GABA + co-edited macromolecules (MM)) and MM-suppressed GABA editing. The unsuppressed water signal from the volume of interest was acquired for concentration referencing. Whole-brain T1-weighted structural images were acquired and segmented to determine gray matter, white matter and cerebrospinal fluid voxel tissue fractions. Water-referenced GABA measurements were fully corrected for tissue-dependent signal relaxation and water visibility effects. The cohort-wide coefficient of variation was 17% for the GABA + data and 29% for the MM-suppressed GABA data. The mean within-site coefficient of variation was 10% for the GABA + data and 19% for the MM-suppressed GABA data. Vendor differences contributed 53% to the total variance in the GABA + data, while the remaining variance was attributed to site- (11%) and participant-level (36%) effects. For the MM-suppressed data, 54% of the variance was attributed to site differences, while the remaining 46% was attributed to participant differences. Results from an exploratory analysis suggested that the vendor differences were related to the unsuppressed water signal acquisition. Discounting the observed vendor-specific effects, water-referenced GABA measurements exhibit similar levels of variance to creatine-referenced GABA measurements. It is concluded that quantification using internal tissue water referencing is a viable and reliable method for the quantification of in vivo GABA levels.