scholarly journals Whole-brain 3D MR fingerprinting brain imaging: clinical validation and feasibility to patients with meningioma

2021 ◽  
Author(s):  
Thomaz R. Mostardeiro ◽  
Ananya Panda ◽  
Robert J. Witte ◽  
Norbert G. Campeau ◽  
Kiaran P. McGee ◽  
...  
Keyword(s):  
White Matter ◽  
Statistical Significance ◽  
Relaxation Times ◽  
Brain Structures ◽  
Centrum Semiovale ◽  
In Vivo Evaluation ◽  
Whole Brain ◽  
Mean Values ◽  
Caudate Head

Abstract Purpose MR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma. Materials and methods A whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman’s ANOVA test. Results MR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001) Conclusions Phantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.

scholarly journals Metabolic counterparts of sodium accumulation in multiple sclerosis: A whole brain 23Na-MRI and fast 1H-MRSI study

2017 ◽  
Vol 25 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Maxime Donadieu ◽  
Yann Le Fur ◽  
Adil Maarouf ◽  
Soraya Gherib ◽  
Ben Ridley ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Regression Models ◽  
Whole Brain ◽  
Sodium Accumulation ◽  
Normal Appearing White Matter ◽  
Clinical Scores ◽  
Z Scores ◽  
Relapsing Remitting Multiple Sclerosis

Background: Increase of brain total sodium concentrations (TSC) is present in multiple sclerosis (MS), but its pathological involvement has not been assessed yet. Objective: To determine in vivo the metabolic counterpart of brain sodium accumulation. Materials/methods: Whole brain 23Na-MR imaging and 3D-1H-EPSI data were collected in 21 relapsing-remitting multiple sclerosis (RRMS) patients and 20 volunteers. Metabolites and sodium levels were extracted from several regions of grey matter (GM), normal-appearing white matter (NAWM) and white matter (WM) T2 lesions. Metabolic and ionic levels expressed as Z-scores have been averaged over the different compartments and used to explain sodium accumulations through stepwise regression models. Results: MS patients showed significant 23Na accumulations with lower choline and glutamate–glutamine (Glx) levels in GM; 23Na accumulations with lower N-acetyl aspartate (NAA), Glx levels and higher Myo-Inositol (m-Ins) in NAWM; and higher 23Na, m-Ins levels with lower NAA in WM T2 lesions. Regression models showed associations of TSC increase with reduced NAA in GM, NAWM and T2 lesions, as well as higher total-creatine, and smaller decrease of m-Ins in T2 lesions. GM Glx levels were associated with clinical scores. Conclusion: Increase of TSC in RRMS is mainly related to neuronal mitochondrial dysfunction while dysfunction of neuro-glial interactions within GM is linked to clinical scores.

An In Vivo Evaluation of Two Types of Files used to Accurately Determine the Diameter of the Apical Constriction of a Root Canal: An In Vivo Study

2009 ◽  
Vol 10 (4) ◽  
pp. 43-50 ◽  
Author(s):  
Narendra Manwar ◽  
Sumeet Darda ◽  
D.D. Shori
Keyword(s):  
Root Canal ◽  
Univariate Analysis ◽  
File Size ◽  
In Vivo Evaluation ◽  
Apical Constriction ◽  
Iso Standard ◽  
Mean Values ◽  
Canal Diameter ◽  
Working Length

Abstract Aim The aim of this study was to compare sizes of the first instrument with or without a taper that binds at the apical constriction of a root canal after coronal flaring. Methods and Materials A total of 310 canals were evaluated in patients presenting for root canal therapy. Canals with intact apices were selected. After gaining straight line endodontic access, the coronal third was flared using Gates-Glidden drills. Working length was determined using an apex locator. ISO Standard K-files (tapered) were passively introduced into the canals starting with a No. 15 file. The first K-file size to bind against the canal walls without pushing and to reach the working length was recorded as the FKFB (First K File to Bind). Next, ISO Standard Lightspeed files (non-tapered instruments) starting with No. 20 were then gently introduced by hand to each canal in ascending order to the working length. The first size of a Lightspeed instrument to bind against the canal walls and reach the working length was recorded as FLSB (First Light Speed to Bind). In all instances a larger file was introduced to ensure it could not reach the same depth (i.e., working length). Statistical analysis was carried out using a univariate analysis of variance (ANOVA). Results The average size of the FLSB to bind against the canal walls first at the working length was approximately two ISO sizes larger than the FKFB (P<0.001). Conclusion The clinician should consider introducing a non-tapered instrument to working length after coronal flaring because determination of the initial narrow apical canal diameter plays a major factor in identifying the extent of final apical shaping. Because the first non-tapered instrument that binds the apical constriction is larger than the corresponding tapered instrument, it better reflects the actual narrow apical diameter of the canal. Clinical Significance The initiation of canal instrumentation with a K-file size three sizes beyond the mean values of the FLSB will result in greater final enlargement of the canal compared to starting with the FKFB. This increased canal enlargement facilitates improved mechanical and chemical cleansing of the root canal ensuring removal of more microorganisms and their substrates, thus, improving the outcome of the treatment. Citation Darda S, Manwar N, Chandak M, Shori DD. An In Vivo Evaluation of Two Types of Files used to Accurately Determine the Diameter of the Apical Constriction of a Root Canal: An In Vivo Study. J Contemp Dent Pract 2009 July; (10)4:043-050.

Measurements of T1 and T2 over Time in Formalin-Fixed Human Whole-Brain Specimens

1992 ◽  
Vol 33 (5) ◽  
pp. 400-404 ◽  
Author(s):  
M. Tovi ◽  
A. Ericsson
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Relaxation Times ◽  
Fixation Procedure ◽  
Whole Brain ◽  
T1 And T2 ◽  
Phospholipid Structure ◽  
Formalin Fixed ◽  
Over Time

Abstract T1 and T2 were measured in 5 formalin-fixed human whole-brain specimens as a function of time. Gray matter/white matter contrast reversal was observed around the 4th day and was considered to be due to the greater decrease in T1 in gray than in white matter. A possible explanation for this is that the decomposition of the myelin phospholipid structure by formalin somewhat counteracts the general reductive effect of the fixation procedure on relaxation times.

scholarly journals Insights into smouldering MS brain pathology with multimodal diffusion tensor and PET imaging

2020 ◽  
Author(s):  
Svetlana Bezukladova ◽  
Jouni Tuisku ◽  
Markus Matilainen ◽  
Anna Vuorimaa ◽  
Marjo Nylund ◽  
...  
Keyword(s):  
White Matter ◽  
Pet Imaging ◽  
Microglial Activation ◽  
Diffusion Tensor ◽  
Volume Ratio ◽  
Translocator Protein ◽  
Control Group ◽  
In Vivo Evaluation ◽  
Conventional Mri

Objective: To evaluate in vivo the co-occurrence of microglial activation and microstructural white matter damage in multiple sclerosis (MS) brain, and to examine their association with clinical disability. Methods: 18-kDa translocator protein (TSPO) brain PET imaging was performed for evaluation of microglial activation by using the radioligand [11C](R)-PK11195. TSPO-binding was evaluated as the distribution volume ratio (DVR) from dynamic PET images. Diffusion tensor imaging (DTI) and conventional MRI were performed at the same time. Mean fractional anisotropy (FA) and mean (MD), axial (AD) and radial (RD) diffusivities were calculated within the whole normal appearing white matter (NAWM) and segmented NAWM regions appearing normal in conventional MRI. 55 MS patients and 15 healthy controls were examined. Results: Microstructural damage was observed in the NAWM of MS brain. DTI parameters of MS patients were significantly altered in the NAWM, when compared to an age- and sex-matched healthy control group: mean FA was decreased, and MD, AD and RD were increased. These structural abnormalities correlated with increased TSPO binding in the whole NAWM and in the temporal NAWM (p<0.05 for all correlations; p<0.01 for RD in the temporal NAWM). Both compromised WM integrity and increased microglial activation in the NAWM correlated significantly with higher clinical disability measured with expanded disability status scale (EDSS). Conclusions: Widespread structural disruption in the NAWM is linked to neuroinflammation, and both phenomena associate with clinical disability. Multimodal PET and DTI imaging allows in vivo evaluation of widespread MS pathology not visible using conventional MRI.

scholarly journals Metabolic connectomics targeting brain pathology in dementia with Lewy bodies

2016 ◽  
Vol 37 (4) ◽  
pp. 1311-1325 ◽  
Author(s):  
Silvia P Caminiti ◽  
Marco Tettamanti ◽  
Arianna Sala ◽  
Luca Presotto ◽  
Sandro Iannaccone ◽  
...  
Keyword(s):  
Dementia With Lewy Bodies ◽  
Estimation Method ◽  
Lewy Bodies ◽  
Occipital Cortex ◽  
Brain Structures ◽  
Brain Regions ◽  
Normal Brain ◽  
Whole Brain ◽  
Metabolic Connectivity

Dementia with Lewy bodies is characterized by α-synuclein accumulation and degeneration of dopaminergic and cholinergic pathways. To gain an overview of brain systems affected by neurodegeneration, we characterized the [18F]FDG-PET metabolic connectivity in 42 dementia with Lewy bodies patients, as compared to 42 healthy controls, using sparse inverse covariance estimation method and graph theory. We performed whole-brain and anatomically driven analyses, targeting cholinergic and dopaminergic pathways, and the α-synuclein spreading. The first revealed substantial alterations in connectivity indexes, brain modularity, and hubs configuration. Namely, decreases in local metabolic connectivity within occipital cortex, thalamus, and cerebellum, and increases within frontal, temporal, parietal, and basal ganglia regions. There were also long-range disconnections among these brain regions, all supporting a disruption of the functional hierarchy characterizing the normal brain. The anatomically driven analysis revealed alterations within brain structures early affected by α-synuclein pathology, supporting Braak’s early pathological staging in dementia with Lewy bodies. The dopaminergic striato-cortical pathway was severely affected, as well as the cholinergic networks, with an extensive decrease in connectivity in Ch1-Ch2, Ch5-Ch6 networks, and the lateral Ch4 capsular network significantly towards the occipital cortex. These altered patterns of metabolic connectivity unveil a new in vivo scenario for dementia with Lewy bodies underlying pathology in terms of changes in whole-brain metabolic connectivity, spreading of α-synuclein, and neurotransmission impairment.

In vivo evaluation of white matter pathology in patients of progressive supranuclear palsy using TBSS

2011 ◽  
Vol 54 (7) ◽  
pp. 771-780 ◽  
Author(s):  
Jitender Saini ◽  
Bhavani Shankara Bagepally ◽  
Mangalore Sandhya ◽  
Shaik Afsar Pasha ◽  
Ravi Yadav ◽  
...  
Keyword(s):  
White Matter ◽  
Progressive Supranuclear Palsy ◽  
In Vivo Evaluation ◽  
White Matter Pathology

scholarly journals Brain structures associated with reading and their abnormalities in dyslexia: a whole-brain analysis

2020 ◽  
Author(s):  
T. Kujala ◽  
A. Thiede ◽  
P. Palo-oja ◽  
P. Virtala ◽  
M. Laasonen ◽  
...  
Keyword(s):  
White Matter ◽  
Grey Matter ◽  
Neurodevelopmental Disorder ◽  
Neuropsychological Testing ◽  
Brain Structures ◽  
Middle Temporal Gyrus ◽  
Subcortical Structures ◽  
Whole Brain ◽  
Technical Reading ◽  
The Right

AbstractDevelopmental dyslexia (DD) is a highly prevalent neurodevelopmental disorder, which often has a devastating influence on the individual’s academic achievement and career. Research on the neural origins of DD has continued for half a century, yielding, however, inconsistent results. The current study was set out to determine abnormalities of grey and white matter volumes in adults with DD and to shed light on neural architectures associated with reading and related skills. To this end, we conducted a whole-brain voxel based morphometry following current recommendations on analysis approaches, coupled with rigorous neuropsychological testing, to characterize the associations between neuroanatomy and skills vital for reading in DD. We found decreased volumes of grey matter in DD, comprising a left-hemispheric network including superior temporal and inferior frontal gyri, insula, the limbic system, and basal ganglia, and white matter, including the right middle temporal gyrus and hippocampus, as well as the right precuneus. These results are both consistent with the most robust previous findings on cortical abnormalities in DD and yield novel insight to the role of subcortical structures in DD, scarcely studied so far. Crucially, areas with decreased grey matter in DD overlapped with brain areas associated with technical reading skills. This supports the conclusion that the grey matter regions that we identified to have a low volume in DD are associated with the core areas vital for reading.

scholarly journals Comparative in vivo evaluation of marketed sustained release and optimized pulsatile formulation of propranolol hydrochloride

2020 ◽  
Vol 11 (2) ◽  
pp. 1896-1901
Author(s):  
Vamsi krishan B ◽  
Babu rao CH ◽  
Saikishore V
Keyword(s):  
Drug Delivery ◽  
Dosage Form ◽  
Statistical Significance ◽  
Oral Intake ◽  
Pharmacokinetic Parameters ◽  
Lag Phase ◽  
Pharmacokinetic Data ◽  
Propranolol Hydrochloride ◽  
In Vivo Evaluation

Chrono pharmaceutical drug delivery system is devoted to the availability of active on a pace that idyllically matches biological requisite of disease treatment. It embodies time controlled and site-specific drug delivery systems, subsequently optimizing therapeutic action and lessening side-effect’s. In the present study optimized pulsatile formulation of Propranolol Hydrochloride ought to deliver drug at pre-set pattern at right time and site is evaluated for pharmacodynamic and pharmacokinetic performance after oral administration and compared with an existing marketed sustained formulation of Propranolol Hcl. The study was carried out in male New Zealand albino rabbits through cross over design pattern and levels of plasma measured by means of LC-MS/MS method. Pharmacokinetic parameters of designed pulsatile formulation was measured and observed to have statistical significance with existing marketed sustained formulation. The In-house pulsatile dosage form able to show lag phase and the mean residence time of pulsatile dosage form (23.20.14h.) was found to be beyond the marketed sustained dosage form (14.8 0.01h.). Pharmacokinetic data revealed a maximum guard against adrenaline levels at 6 h post oral intake and dropped to 50% after 12 h with Marketed formulation. Whereas in case of pulsatile formulation administration a maximum protection was obtained at 12 h. and continued over a period of 18 h. It is concluded that the designed pulsatile formulation offers a promising way of drug release for a programmed time period at desired site, once the administration time and pulse time are aligned with circadian pattern.

In vivo relaxation times of gray matter and white matter in spinal cord

1999 ◽  
Vol 17 (4) ◽  
pp. 623-626 ◽  
Author(s):  
Ponnada Narayana ◽  
David Fenyes ◽  
Nicholas Zacharopoulos
Keyword(s):  
Spinal Cord ◽  
White Matter ◽  
Gray Matter ◽  
Relaxation Times

scholarly journals Evaluating High Spatial Resolution Diffusion Kurtosis Imaging at 3T: Reproducibility and Quality of Fit

2020 ◽  
Author(s):  
Loxlan W. Kasa ◽  
Roy A.M. Haast ◽  
Tristan K. Kuehn ◽  
Farah N. Mushtaha ◽  
Corey A. Baron ◽  
...  
Keyword(s):  
White Matter ◽  
High Resolution ◽  
Diffusion Kurtosis Imaging ◽  
List Type ◽  
Whole Brain ◽  
B Values ◽  
Phantom Data ◽  
Diffusion Kurtosis ◽  
Fitting Accuracy

ABSTRACTBackgroundDiffusion kurtosis imaging (DKI) quantifies the microstructure’s non-Gaussian diffusion properties. However, it has increased fitting parameters and requires higher b-values. Evaluation of DKI reproducibility is important for clinical purposes.PurposeTo assess reproducibility in whole-brain high resolution DKI at varying b-values.Study TypeProspective.Subjects and PhantomsForty-four individuals from the test-retest Human Connectome Project (HCP) database and twelve 3D-printed tissue mimicking phantoms.Field Strength/SequenceMultiband echo-planar imaging for in vivo and phantom diffusion-weighted imaging at 3T and 9.4T respectively. MPRAGE at 3T for in vivo structural data.AssessmentFrom HCP data with b-value =1000,2000,3000 s/mm2 (dataset A), two additional datasets with b-values=1000, 3000 s/mm2 (dataset B) and b-values=1000, 2000 s/mm2 (dataset C) were extracted. Estimated DKI metrics from each dataset were used for evaluating reproducibility and fitting quality in whole-brain white matter (WM), region of interest (ROI) and gray matter (GM).Statistical TestsDKI reproducibility was assessed using the within-subject coefficient of variation (CoV), fitting residuals to evaluate DKI fitting accuracy and Pearson’s correlation to investigate presence of systematic biases.ResultsCompared to dataset C, the CoV from DKI parameters from datasets A and B were comparable, with WM and GM CoVs <20%, while differences between datasets were smaller for the DKI-derived DTI parameters. Slightly higher fitting residuals were observed in dataset C compared to A and B, but lower residuals in dataset B were detected for the WM ROIs. A similar trend was observed for the phantom data with comparable CoVs at varying fiber orientations for datasets A and B. In addition, dataset C was characterized by higher residuals across the different fiber crossings.Data ConclusionThe comparable reproducibility of DKI maps between datasets A and B observed in the in vivo and phantom data indicates that high reproducibility can still be achieved within a reasonable scan time, supporting DKI for clinical purposes.HIGHLIGHTS:Reproducibility and fitting accuracy of high resolution DKI were evaluated as function of available b-values.A DKI dataset with b-values of 1000 and 3000 s/mm2 performs equally well as the original HCP three-shell dataset, while a dataset with b-values of 1000 and 2000 s/mm2 has lower reproducibility and fitting quality.In vivo results were verified using phantoms capable of mimicking different white matter configurations.These results suggest that DKI data can be obtained within less time, without sacrificing data quality.

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