scholarly journals How to Arrange Follow-Up Time-Intervals for Longitudinal Brain MRI Studies in Neurodegenerative Diseases

2021 ◽  
Vol 15 ◽  
Author(s):  
Hans-Peter Müller ◽  
Anna Behler ◽  
G. Bernhard Landwehrmeyer ◽  
Hans-Jürgen Huppertz ◽  
Jan Kassubek
Keyword(s):  
Temporal Dynamics ◽  
Linear Trend ◽  
Neurological Diseases ◽  
Brain Mri ◽  
Time Intervals ◽  
Mri Studies ◽  
Longitudinal Mri ◽  
Longitudinal Imaging ◽  
Analytical Approaches

BackgroundLongitudinal brain MRI monitoring in neurodegeneration potentially provides substantial insights into the temporal dynamics of the underlying biological process, but is time- and cost-intensive and may be a burden to patients with disabling neurological diseases. Thus, the conceptualization of follow-up time-intervals in longitudinal MRI studies is an essential challenge and substantial for the results. The objective of this work is to discuss the association of time-intervals and the results of longitudinal trends in the frequently used design of one baseline and two follow-up scans.MethodsDifferent analytical approaches for calculating the linear trend of longitudinal parameters were studied in simulations including their performance of dealing with outliers; these simulations were based on the longitudinal striatum atrophy in MRI data of Huntington’s disease patients, detected by atlas-based volumetry (ABV).ResultsFor the design of one baseline and two follow-up visits, the simulations with outliers revealed optimum results for identical time-intervals between baseline and follow-up scans. However, identical time-intervals between the three acquisitions lead to the paradox that, depending on the fit method, the first follow-up scan results do not influence the final results of a linear trend analysis.ConclusionsThis theoretical study analyses how the design of longitudinal imaging studies with one baseline and two follow-up visits influences the results. Suggestions for the analysis of longitudinal trends are provided.

scholarly journals Semiautomatic segmentation and follow-up of multicomponent low-grade tumors in longitudinal brain MRI studies

2014 ◽  
Vol 41 (5) ◽  
pp. 052303 ◽  
Author(s):  
Lior Weizman ◽  
Liat Ben Sira ◽  
Leo Joskowicz ◽  
Daniel L. Rubin ◽  
Kristen W. Yeom ◽  
...  
Keyword(s):  
Brain Mri ◽  
Low Grade ◽  
Semiautomatic Segmentation ◽  
Mri Studies

Long-term seizure outcomes after pediatric temporal lobectomy: does brain MRI lesion matter?

2019 ◽  
Vol 24 (2) ◽  
pp. 200-208
Author(s):  
Ravindra Arya ◽  
Francesco T. Mangano ◽  
Paul S. Horn ◽  
Sabrina K. Kaul ◽  
Serena K. Kaul ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Hippocampal Sclerosis ◽  
Brain Mri ◽  
Temporal Lobectomy ◽  
Seizure Freedom ◽  
Seizure Onset

OBJECTIVEThere is emerging data that adults with temporal lobe epilepsy (TLE) without a discrete lesion on brain MRI have surgical outcomes comparable to those with hippocampal sclerosis (HS). However, pediatric TLE is different from its adult counterpart. In this study, the authors investigated if the presence of a potentially epileptogenic lesion on presurgical brain MRI influences the long-term seizure outcomes after pediatric temporal lobectomy.METHODSChildren who underwent temporal lobectomy between 2007 and 2015 and had at least 1 year of seizure outcomes data were identified. These were classified into lesional and MRI-negative groups based on whether an epilepsy-protocol brain MRI showed a lesion sufficiently specific to guide surgical decisions. These patients were also categorized into pure TLE and temporal plus epilepsies based on the neurophysiological localization of the seizure-onset zone. Seizure outcomes at each follow-up visit were incorporated into a repeated-measures generalized linear mixed model (GLMM) with MRI status as a grouping variable. Clinical variables were incorporated into GLMM as covariates.RESULTSOne hundred nine patients (44 females) were included, aged 5 to 21 years, and were classified as lesional (73%), MRI negative (27%), pure TLE (56%), and temporal plus (44%). After a mean follow-up of 3.2 years (range 1.2–8.8 years), 66% of the patients were seizure free for ≥ 1 year at last follow-up. GLMM analysis revealed that lesional patients were more likely to be seizure free over the long term compared to MRI-negative patients for the overall cohort (OR 2.58, p < 0.0001) and for temporal plus epilepsies (OR 1.85, p = 0.0052). The effect of MRI lesion was not significant for pure TLE (OR 2.64, p = 0.0635). Concordance of ictal electroencephalography (OR 3.46, p < 0.0001), magnetoencephalography (OR 4.26, p < 0.0001), and later age of seizure onset (OR 1.05, p = 0.0091) were associated with a higher likelihood of seizure freedom. The most common histological findings included cortical dysplasia types 1B and 2A, HS (40% with dual pathology), and tuberous sclerosis.CONCLUSIONSA lesion on presurgical brain MRI is an important determinant of long-term seizure freedom after pediatric temporal lobectomy. Pediatric TLE is heterogeneous regarding etiologies and organization of seizure-onset zones with many patients qualifying for temporal plus nosology. The presence of an MRI lesion determined seizure outcomes in patients with temporal plus epilepsies. However, pure TLE had comparable surgical seizure outcomes for lesional and MRI-negative groups.

scholarly journals Progression of cerebral infarction before and after thrombectomy is modified by prehospital pathways

2021 ◽  
pp. neurintsurg-2020-017155
Author(s):  
Alexander M Kollikowski ◽  
Franziska Cattus ◽  
Julia Haag ◽  
Jörn Feick ◽  
Alexander G März ◽  
...  
Keyword(s):  
Patient Characteristics ◽  
Large Vessel ◽  
Stroke Severity ◽  
Large Vessel Occlusion ◽  
Time Intervals ◽  
Vessel Occlusion ◽  
Before And After ◽  
Transferred Patients ◽  
Stroke Center

BackgroundEvidence of the consequences of different prehospital pathways before mechanical thrombectomy (MT) in large vessel occlusion stroke is inconclusive. The aim of this study was to investigate the infarct extent and progression before and after MT in directly admitted (mothership) versus transferred (drip and ship) patients using the Alberta Stroke Program Early CT Score (ASPECTS).MethodsASPECTS of 535 consecutive large vessel occlusion stroke patients eligible for MT between 2015 to 2019 were retrospectively analyzed for differences in the extent of baseline, post-referral, and post-recanalization infarction between the mothership and drip and ship pathways. Time intervals and transport distances of both pathways were analyzed. Multiple linear regression was used to examine the association between infarct progression (baseline to post-recanalization ASPECTS decline), patient characteristics, and logistic key figures.ResultsASPECTS declined during transfer (9 (8–10) vs 7 (6-9), p<0.0001), resulting in lower ASPECTS at stroke center presentation (mothership 9 (7–10) vs drip and ship 7 (6–9), p<0.0001) and on follow-up imaging (mothership 7 (4–8) vs drip and ship 6 (3–7), p=0.001) compared with mothership patients. Infarct progression was significantly higher in transferred patients (points lost, mothership 2 (0–3) vs drip and ship 3 (2–6), p<0.0001). After multivariable adjustment, only interfacility transfer, preinterventional clinical stroke severity, the degree of angiographic recanalization, and the duration of the thrombectomy procedure remained predictors of infarct progression (R2=0.209, p<0.0001).ConclusionsInfarct progression and postinterventional infarct extent, as assessed by ASPECTS, varied between the drip and ship and mothership pathway, leading to more pronounced infarction in transferred patients. ASPECTS may serve as a radiological measure to monitor the benefit or harm of different prehospital pathways for MT.

scholarly journals Hemochromatosis Mutations, Brain Iron Imaging, and Dementia in the UK Biobank Cohort

2021 ◽  
pp. 1-9
Author(s):  
Janice L. Atkins ◽  
Luke C. Pilling ◽  
Christine J. Heales ◽  
Sharon Savage ◽  
Chia-Ling Kuo ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Brain Mri ◽  
European Ancestry ◽  
Uk Biobank ◽  
Brain Iron ◽  
Mri Features ◽  
Incident Dementia ◽  
Hfe Mutations ◽  
The Uk

Background: Brain iron deposition occurs in dementia. In European ancestry populations, the HFE p.C282Y variant can cause iron overload and hemochromatosis, mostly in homozygous males. Objective: To estimated p.C282Y associations with brain MRI features plus incident dementia diagnoses during follow-up in a large community cohort. Methods: UK Biobank participants with follow-up hospitalization records (mean 10.5 years). MRI in 206 p.C282Y homozygotes versus 23,349 without variants, including T2 * measures (lower values indicating more iron). Results: European ancestry participants included 2,890 p.C282Y homozygotes. Male p.C282Y homozygotes had lower T2 * measures in areas including the putamen, thalamus, and hippocampus, compared to no HFE mutations. Incident dementia was more common in p.C282Y homozygous men (Hazard Ratio HR = 1.83; 95% CI 1.23 to 2.72, p = 0.003), as was delirium. There were no associations in homozygote women or in heterozygotes. Conclusion: Studies are needed of whether early iron reduction prevents or slows related brain pathologies in male HFE p.C282Y homozygotes.

Arthroscopic Versus Open Anterior Shoulder Stabilization: A Prospective Randomized Clinical Trial With 15-Year Follow-up With an Assessment of the Glenoid Being “On-Track” and “Off-Track” as a Predictor of Failure

2021 ◽  
pp. 036354652110182
Author(s):  
Craig R. Bottoni ◽  
John D. Johnson ◽  
Liang Zhou ◽  
Sarah G. Raybin ◽  
James S. Shaha ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Shoulder Instability ◽  
Anterior Shoulder Instability ◽  
Shoulder Stabilization ◽  
Mri Studies ◽  
Open Stabilization ◽  
The Mean ◽  
Recurrent Anterior Shoulder Instability

Background: Recent studies have demonstrated equivalent short-term results when comparing arthroscopic versus open anterior shoulder stabilization. However, none have evaluated the long-term clinical outcomes of patients after arthroscopic or open anterior shoulder stabilization, with inclusion of an assessment of preoperative glenoid tracking. Purpose: To compare long-term clinical outcomes of patients with recurrent anterior shoulder instability randomized to open and arthroscopic stabilization groups. Additionally, preoperative magnetic resonance imaging (MRI) studies were used to assess whether the shoulders were “on-track” or “off-track” to ascertain a prediction of increased failure risk. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A consecutive series of 64 patients with recurrent anterior shoulder instability were randomized to receive either arthroscopic or open stabilization by a single surgeon. Follow-up assessments were performed at minimum 15-year follow-up using established postoperative evaluations. Clinical failure was defined as any recurrent dislocation postoperatively or subjective instability. Preoperative MRI scans were obtained to calculate the glenoid track and designate shoulders as on-track or off-track. These results were then correlated with the patients’ clinical results at their latest follow-up. Results: Of 64 patients, 60 (28 arthroscopic and 32 open) were contacted or examined for follow-up (range, 15-17 years). The mean age at the time of surgery was 25 years (range, 19-42 years), while the mean age at the time of this assessment was 40 years (range, 34-57 years). The rates of arthroscopic and open long-term failure were 14.3% (4/28) and 12.5% (4/32), respectively. There were no differences in subjective shoulder outcome scores between the treatment groups. Of the 56 shoulders, with available MRI studies, 8 (14.3%) were determined to be off-track. Of these 8 shoulders, there were 2 surgical failures (25.0%; 1 treated arthroscopically, 1 treated open). In the on-track group, 6 of 48 had failed surgery (12.5%; 3 open, 3 arthroscopic [ P = .280]). Conclusion: Long-term clinical outcomes were comparable at 15 years postoperatively between the arthroscopic and open stabilization groups. The presence of an off-track lesion may be associated with a higher rate of recurrent instability in both cohorts at long-term follow-up; however, this study was underpowered to verify this situation.

scholarly journals Debridement, Antibiotics, and Implant Retention Is a Viable Treatment Option for Early Periprosthetic Joint Infection Presenting More Than 4 Weeks After Index Arthroplasty

2019 ◽  
Vol 71 (3) ◽  
pp. 630-636 ◽  
Author(s):  
Claudia A M Löwik ◽  
Javad Parvizi ◽  
Paul C Jutte ◽  
Wierd P Zijlstra ◽  
Bas A S Knobben ◽  
...  
Keyword(s):  
Treatment Failure ◽  
Periprosthetic Joint Infection ◽  
Joint Infection ◽  
Viable Option ◽  
Time Intervals ◽  
Implant Retention ◽  
Time Point ◽  
Viable Treatment

Abstract Background The success of debridement, antibiotics, and implant retention (DAIR) in early periprosthetic joint infection (PJI) largely depends on the presence of a mature biofilm. At what time point DAIR should be disrecommended is unknown. This multicenter study evaluated the outcome of DAIR in relation to the time after index arthroplasty. Methods We retrospectively evaluated PJIs occurring within 90 days after surgery and treated with DAIR. Patients with bacteremia, arthroscopic debridements, and a follow-up &lt;1 year were excluded. Treatment failure was defined as (1) any further surgical procedure related to infection; (2) PJI-related death; or (3) use of long-term suppressive antibiotics. Results We included 769 patients. Treatment failure occurred in 294 patients (38%) and was similar between time intervals from index arthroplasty to DAIR: the failure rate for Week 1–2 was 42% (95/226), the rate for Week 3–4 was 38% (143/378), the rate for Week 5–6 was 29% (29/100), and the rate for Week 7–12 was 42% (27/65). An exchange of modular components was performed to a lesser extent in the early post-surgical course compared with the late course (41% vs 63%, respectively; P &lt; .001). The causative microorganisms, comorbidities, and durations of symptoms were comparable between time intervals. Conclusions DAIR is a viable option in patients with early PJI presenting more than 4 weeks after index surgery, as long as DAIR is performed within at least 1 week after the onset of symptoms and modular components can be exchanged.

scholarly journals REscan: inferring repeat expansions and structural variation in paired-end short read sequencing data

2020 ◽  
Author(s):  
Russell Lewis McLaughlin
Keyword(s):  
Structural Variation ◽  
Sequence Data ◽  
Neurological Diseases ◽  
Repeat Expansion ◽  
Sequencing Data ◽  
Short Read ◽  
Short Read Sequencing ◽  
Repeat Expansions ◽  
Paired End Sequencing

Abstract Motivation Repeat expansions are an important class of genetic variation in neurological diseases. However, the identification of novel repeat expansions using conventional sequencing methods is a challenge due to their typical lengths relative to short sequence reads and difficulty in producing accurate and unique alignments for repetitive sequence. However, this latter property can be harnessed in paired-end sequencing data to infer the possible locations of repeat expansions and other structural variation. Results This article presents REscan, a command-line utility that infers repeat expansion loci from paired-end short read sequencing data by reporting the proportion of reads orientated towards a locus that do not have an adequately mapped mate. A high REscan statistic relative to a population of data suggests a repeat expansion locus for experimental follow-up. This approach is validated using genome sequence data for 259 cases of amyotrophic lateral sclerosis, of which 24 are positive for a large repeat expansion in C9orf72, showing that REscan statistics readily discriminate repeat expansion carriers from non-carriers. Availabilityand implementation C source code at https://github.com/rlmcl/rescan (GNU General Public Licence v3).

Healing of Carotid Stents: A Prospective Duplex Ultrasound Study

2003 ◽  
Vol 10 (3) ◽  
pp. 636-642 ◽  
Author(s):  
Andrea Willfort-Ehringer ◽  
Ramazanali Ahmadi ◽  
Michael E. Gschwandtner ◽  
Angelika Haumer ◽  
Gottfried Heinz ◽  
...  
Keyword(s):  
Carotid Arteries ◽  
Duplex Ultrasound ◽  
Stable Phase ◽  
Carotid Stent ◽  
Time Intervals ◽  
Unstable Phase ◽  
Ultrasound Study ◽  
Maximal Thickness ◽  
Second Year

Purpose: To study the dynamics of carotid stent healing over a 2-year period using duplex ultrasound imaging. Methods: One hundred twelve patients with 121 successfully stented carotid arteries were examined with color-coded duplex ultrasound the day after the stent procedure and at 1, 3, 6, 12, and 24 months in follow-up. The maximal thickness and echogenicity of the layer between the stent and the perfused lumen (SPL) were evaluated. Echogenicity was classified as echogenic if the SPL layer was clearly detected in B mode and echolucent if the SPL layer was barely visible in B mode, its border defined by assistance of color-coded flow. Results: At day 1, an echolucent SPL layer with a median thickness of 0.7 mm was interpreted as a thrombotic layer, which decreased at 1 month to practically zero (i.e., not detectable). In follow-up, increases in thickness (mainly up to 6 months) and echogenicity (up to 12 months) of the SPL layer were interpreted as neointimal ingrowth. At 3, 6, and 12 months, the median maximal thickness of the SPL layer was 0.5 mm, 0.9 mm, and 1.0 mm, respectively, whereas the percentage of patients with an echogenic SPL layer was 27% (32/119), 56% (66/117), and 95% (105/110), respectively, at the same time intervals. No further change was observed at the 24-month examination. Conclusions: Three phases of carotid stent incorporation are defined: (1) an early unstable period soon after stent placement with an echolucent (thrombotic) SPL layer, (2) a moderately unstable phase with ingrowing neointima (1–12 months), and (3) a stable phase from the second year on. These data may indicate the need for different intensities of therapy and surveillance intervals.

Learning as a Function of Subliminal Reinforcements

1963 ◽  
Vol 12 (2) ◽  
pp. 387-398
Author(s):  
Austin Jones ◽  
Melvin Manis ◽  
Bernard Weiner
Keyword(s):  
Relative Frequency ◽  
Probability Learning ◽  
Linear Trend ◽  
Stimulus Category ◽  
Time Intervals ◽  
Significant Linear Trend ◽  
Tachistoscopic Presentation ◽  
Stimulus Classes ◽  
Learning Trials ◽  
Correct Discrimination

Three studies were conducted to assess the effects of subliminal reinforcements on learning. In the first two, Ss were given a discrimination task in which five geometric forms, repeated over 100 trials, were to be assigned to one of two categories. The categories were unbalanced; four geometric forms comprised one category, the remaining form the other. Response was required on each trial. Immediately after each response, the appropriate reinforcing word, “Right” or “Wrong,” was flashed at a subliminal brightness-contrast In Exp. I, under low motivation (without money incentives), Ss showed no learning of the correct discrimination, nor any evidence of probability learning with respect to relative frequency of stimulus categories. In Exp. II, the above procedure was replicated with money as the incentive. There again was no evidence of discrimination learning, i.e., acquisition of the correct response. There was, however, a significant linear trend ( p < .05) in the proportion of responses made to the more frequent stimulus category; Ss showed an increasing tendency to “match” the relative frequency of their two classes of response with the corresponding two stimulus classes. In Exp. III, Ss who were motivated by a money incentive attempted to guess whether E was thinking of an odd or an even number. Following each response, Ss were reinforced by tachistoscopic presentation of the word “Right” or “Wrong,” at time intervals which were too brief to permit recognition; half of the Ss were positively reinforced for emitting the response “Odd,” and half for the response “Even.” After 100 learning trials had been completed, the reinforcement contingencies were switched for an additional 20 trials, e.g., Ss who had been reinforced for “Odd” were now reinforced for “Even.” Ss in Exp. III showed no evidence of probability learning. Some possible explanations for the conflicting results of Exps. II and III were discussed.

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