scholarly journals Quantitative T1 mapping of the normal brain from early infancy to adulthood

2020 ◽  
Author(s):  
Daniel Gräfe ◽  
Jens Frahm ◽  
Andreas Merkenschlager ◽  
Dirk Voit ◽  
Franz Wolfgang Hirsch
Keyword(s):  
White Matter ◽  
Spatial Resolution ◽  
Gray Matter ◽  
T1 Mapping ◽  
Relaxation Times ◽  
Early Infancy ◽  
Normal Brain ◽  
Regression Equations ◽  
T1 Relaxation ◽  
Pediatric Brain

Abstract Background Quantitative mapping of MRI relaxation times is expected to uncover pathological processes in the brain more subtly than standard MRI techniques with weighted contrasts. So far, however, most mapping techniques suffer from a long measuring time, low spatial resolution or even sensitivity to magnetic field inhomogeneity. Objective To obtain T1 relaxation times of the normal brain from early infancy to adulthood using a novel technique for fast and accurate T1 mapping at high spatial resolution. Materials and methods We performed whole-brain T1 mapping within less than 3 min in 100 patients between 2 months and 18 years of age with normal brain at a field strength of 3 T. We analyzed T1 relaxation times in several gray-matter nuclei and white matter. Subsequently, we derived regression equations for mean value and confidence interval. Results T1 relaxation times of the pediatric brain rapidly decrease in all regions within the first 3 years of age, followed by a significantly weaker decrease until adulthood. These characteristics are more pronounced in white matter than in deep gray matter. Conclusion Regardless of age, quantitative T1 mapping of the pediatric brain is feasible in clinical practice. Normal age-dependent values should contribute to improved discrimination of subtle intracerebral alterations.

scholarly journals Quantitative T1 mapping under precisely controlled graded hyperoxia at 7T

2016 ◽  
Vol 37 (4) ◽  
pp. 1461-1469 ◽  
Author(s):  
Alex A Bhogal ◽  
Jeroen CW Siero ◽  
Jaco Zwanenburg ◽  
Peter R Luijten ◽  
Marielle EP Philippens ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
White Matter ◽  
T1 Mapping ◽  
Brain Parenchyma ◽  
Arterial Oxygen ◽  
Longitudinal Magnetization ◽  
Fluid Content ◽  
T1 Relaxation ◽  
End Tidal ◽  
Induced Changes

Increasing the concentration of oxygen dissolved in water is known to increase the recovery rate (R1 = 1/T1) of longitudinal magnetization (T1 relaxation). Direct T1 changes in response to precise hyperoxic gas challenges have not yet been quantified and the actual effect of increasing arterial oxygen concentration on the T1 of brain parenchyma remains unclear. The aim of this work was to use quantitative T1 mapping to measure tissue T1 changes in response to precisely targeted hyperoxic respiratory challenges ranging from baseline end-tidal oxygen (PetO2) to approximately 500 mmHg. We did not observe measureable T1 changes in either gray matter or white matter parenchymal tissue. The T1 of peripheral cerebrospinal fluid located within the sulci, however, was reduced as a function of PetO2. No significant T1 changes were observed in the ventricular cerebrospinal fluid under hyperoxia. Our results indicate that care should be taken to distinguish actual T1 changes from those which may be related to partial volume effects with cerebrospinal fluid, or regions with increased fluid content such as edema when examining hyperoxia-induced changes in T1 using methods based on T1-weighted imaging.

[14C]iodoantipyrine and microsphere blood flow estimates in cat brain

1987 ◽  
Vol 253 (5) ◽  
pp. H1289-H1297
Author(s):  
F. J. Schuier ◽  
S. C. Jones ◽  
T. Fedora ◽  
M. Reivich
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Spatial Resolution ◽  
Gray Matter ◽  
Local Cerebral Blood Flow ◽  
Normal Appearance ◽  
Diffusion Limited ◽  
Cat Brain ◽  
Temporal And Spatial

A comparison of local cerebral blood flow estimates with the microsphere and the 4-[N-methyl-14C]iodoantipyrine ([14C]IAP) techniques has been performed in cats. Good correlation of [14C]IAP with microsphere flow estimates in the gray matter was found. In the white matter, however, [14C]IAP flow estimates were consistently lower than microsphere flow estimates. Error analysis of both techniques and comparison with previous studies suggest that peculiarities of white matter arterial vasculature with preferential microsphere accumulation may lead to this discrepancy. Microspheres did not interfere with flow as shown by the normal appearance of subsequent [14C]IAP autoradiograms. The number of microspheres seen on autoradiograms was used for an estimate of microvessels blocked by spheres and found to be negligible. The study also demonstrates that [14C]IAP is not diffusion limited up to the observed flow values of 2 ml.g-1.min-1. Both techniques might be used together for a combination of their respective advantages, which are temporal and spatial resolution for microsphere and [14C]IAP, respectively.

MTR and T1 provide complementary information in MS NAWM, but not in lesions

2000 ◽  
Vol 6 (5) ◽  
pp. 327-331 ◽  
Author(s):  
C M Griffin ◽  
G JM Parker ◽  
G J Barker ◽  
A J Thompson ◽  
D H Miller
Keyword(s):  
Relaxation Time ◽  
White Matter ◽  
Mixed Model ◽  
Relaxation Times ◽  
Tissue Type ◽  
Tissue Characterisation ◽  
Complementary Information ◽  
T1 Relaxation Time ◽  
T1 Relaxation ◽  
The Relationship

MTR and T1 relaxation times are abnormal in MS lesions and NAWM, and may reflect tissue damage such as demyelination and axonal loss. Their relationship and potential to provide complementary information in tissue characterisation is explored. The aim of this study was to document the relationship between magnetisation transfer ratio (MTR) and T1 relaxation time in Multiple Sclerosis (MS) lesions and normal appearing white matter (NAWM) in order to determine whether the combination provides a more comprehensive tissue characterisation than either parameter in isolation. Ten patients with relapsing remitting MS and 10 age matched healthy controls underwent imaging using a protocol which included the measurement of both MTR and T1 relaxation times. The MTR and T1 values were compared statistically using a commonly adopted correlation approach and a mixed-model regression approach. There was a strong correlation between MTR and T1 in MS lesions (r=0.74). The correlation was seen equally in T1 hypointense and isointense lesions. The relationship was much weaker in MS NAWM (r=0.24) and no correlation was found in control white matter (r=0.06). Mixed-model regression analysis confirmed that the relationship between T1 and MTR is strongly dependent upon tissue type (MS lesion, MS NAWM, or control white matter). The relationship between MTR and T1 relaxation time measurements varies markedly between pathological and normal tissue types. In MS, the complementary information obtained from MTR and T1 is most apparent in NAWM. The results emphasise the potential for combinations of MR parameters to improve tissue characterisation, which in turn should improve understanding of disease pathology and treatment monitoring.

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 T1 Relaxation Times in the Cortex and Thalamus Are Associated With Working Memory and Information Processing Speed in Patients With Multiple Sclerosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Christian Thaler ◽  
Isabelle Hartramph ◽  
Jan-Patrick Stellmann ◽  
Christoph Heesen ◽  
Maxim Bester ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Working Memory ◽  
Cognitive Impairment ◽  
Information Processing ◽  
Processing Speed ◽  
T1 Mapping ◽  
Relaxation Times ◽  
Healthy Controls ◽  
Information Processing Speed ◽  
T1 Relaxation

Background: Cortical and thalamic pathologies have been associated with cognitive impairment in patients with multiple sclerosis (MS).Objective: We aimed to quantify cortical and thalamic damage in patients with MS using a high-resolution T1 mapping technique and to evaluate the association of these changes with clinical and cognitive impairment.Methods: The study group consisted of 49 patients with mainly relapsing-remitting MS and 17 age-matched healthy controls who received 3T MRIs including a T1 mapping sequence (MP2RAGE). Mean T1 relaxation times (T1-RT) in the cortex and thalami were compared between patients with MS and healthy controls. Additionally, correlation analysis was performed to assess the relationship between MRI parameters and clinical and cognitive disability.Results: Patients with MS had significantly decreased normalized brain, gray matter, and white matter volumes, as well as increased T1-RT in the normal-appearing white matter, compared to healthy controls (p < 0.001). Partial correlation analysis with age, sex, and disease duration as covariates revealed correlations for T1-RT in the cortex (r = −0.33, p < 0.05), and thalami (right thalamus: r = −0.37, left thalamus: r = −0.50, both p < 0.05) with working memory and information processing speed, as measured by the Symbol-Digit Modalities Test.Conclusion: T1-RT in the cortex and thalamus correlate with information processing speed in patients with MS.

Abstract 18706: Multi-Sequence Non-Contrast MRI Characterisation of Experimental Venous Thrombi Predicts Susceptibility to Lysis and is Feasible in Man

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Prakash Saha ◽  
Alkystis Phinikaridou ◽  
Marcelo E Andia ◽  
Ashish S Patel ◽  
Steven P Grover ◽  
...  
Keyword(s):  
T1 Mapping ◽  
Relaxation Times ◽  
Magnetisation Transfer ◽  
Roc Curve Analysis ◽  
Venous Thrombus ◽  
Vein Thrombosis ◽  
Diffusion Weighted Images ◽  
T1 Relaxation ◽  
Apparent Diffusion ◽  
Deep Vein

Introduction: We have previously demonstrated that non-contrast MRI using magnetisation transfer rate (MTR), apparent diffusion coefficient (ADC) and T1 mapping can characterise different aspects of organisation in a resolving venous thrombus. We now investigate whether the combination of these non-contrast agent MRI sequences can be used to identify thrombi suitable for lysis in an experimental model, and whether multi-sequence thrombus imaging (MSTI) can be translated to man. Methods: Magnetisation transfer, diffusion weighted images and T1 relaxation times were measured at days 2, 4, 7, 10, 14, 21 and 28 after venous thrombus induction in 8-10wk old male BALB/C mice (n=8/gp). Tissue plasminogen activator (10mg/kg) was administered through tail vein injection immediately after imaging at each time point and mice scanned 24hrs later to evaluate the effect of lysis. This was considered successful if more than 50% of the vein recanalised. Murine imaging sequences were combined and optimised to image the pelvic veins in man using healthy volunteers in order to produce a clinically useable imaging card. MSTI sequences were validated using phantoms before application to patients with iliofemoral deep vein thrombosis (DVT) undergoing lysis. Results: ROC curve analysis shows that the combination of MTR smaller than 2,900(%/cm3), ADC larger than 0.93(x10-3 mm2/s) and T1 shorter than 784ms has a sensitivity of 88% and specificity of 97% to identify experimental thrombi amenable to lysis. MSTI is feasible in man, with optimisation leading to successful characterisation of iliofemoral DVT in under 25mins (Figure 1). Conclusions: Non-contrast MR imaging, using a combination of MTR, ADC and T1 mapping, accurately identifies experimental venous thrombi susceptible to lysis. These MSTI sequences can also be readily translated to man where may find utility in characterising the age and structure of thrombus, and to stratify patients undergoing thrombolysis.

Characterization of periventricular edema in normal-pressure hydrocephalus by measurement of water proton relaxation times

1990 ◽  
Vol 73 (6) ◽  
pp. 864-870 ◽  
Author(s):  
Norihiko Tamaki ◽  
Takayuki Shirakuni ◽  
Kazumasa Ehara ◽  
Satoshi Matsumoto
Keyword(s):  
Relaxation Time ◽  
White Matter ◽  
Gray Matter ◽  
Normal Pressure Hydrocephalus ◽  
Relaxation Times ◽  
Normal Pressure ◽  
Water Proton ◽  
Proton Relaxation ◽  
Csf Shunting ◽  
Significant Difference

✓ The magnetic resonance longitudinal relaxation time (T1) and transverse relaxation time (T2) of the water proton of the periventricular white and cortical gray matter were measured for 17 control patients and 21 patients with suspected normal-pressure hydrocephalus (NPH). Of the latter group, 14 showed good response to shunting (true-NPH group) and seven showed no response (false-NPH group). In the true-NPH group, both the T1 and the T2 of the periventricular white matter were significantly prolonged compared to the control values, and slowly shortened after cerebrospinal fluid (CSF) shunting. The true-NPH group showed significantly longer T1 and T2 of the white matter than did the false-NPH group. The T1 and T2 of the white matter were longer than those of the gray matter in this group, which was the reverse of the relationship observed in the control patients. In the white matter of the false-NPH group, there was a significant prolongation of T1 only; no difference was seen in the T2 compared to control values. There was no change in either T1 or T2 of this region after CSF shunting. The false-NPH group showed no significant difference in either T1 or T2 between the white and the gray matter. There was no difference in either T1 or T2 of the gray matter between the false-NPH and control groups or between preshunt and postshunt measurements in each patient group. It is suggested that a distinction between true- and false-NPH, which cannot be made from the radiographic appearance alone, may be possible from measurement of relaxation times. The mechanism of varied relaxation behavior between two entities may be explained by a difference in properties of the biological water and its environment.

scholarly journals Shaping of Regional Differences in Oligodendrocyte Dynamics by Regional Heterogeneity of the Pericellular Microenvironment

2021 ◽  
Vol 15 ◽  
Author(s):  
Amin Sherafat ◽  
Friederike Pfeiffer ◽  
Akiko Nishiyama
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Regional Differences ◽  
Phenotypic Variability ◽  
Adult Brain ◽  
Normal Brain ◽  
Regional Heterogeneity ◽  
Myelin Sheaths ◽  
Oligodendrocyte Precursor ◽  
Functional States

Oligodendrocyte precursor cells (OPCs) are glial cells that differentiate into mature oligodendrocytes (OLs) to generate new myelin sheaths. While OPCs are distributed uniformly throughout the gray and white matter in the developing and adult brain, those in white matter proliferate and differentiate into oligodendrocytes at a greater rate than those in gray matter. There is currently lack of evidence to suggest that OPCs comprise genetically and transcriptionally distinct subtypes. Rather, the emerging view is that they exist in different cell and functional states, depending on their location and age. Contrary to the normal brain, demyelinated lesions in the gray matter of multiple sclerosis brains contain more OPCs and OLs and are remyelinated more robustly than those in white matter. The differences in the dynamic behavior of OL lineage cells are likely to be influenced by their microenvironment. There are regional differences in astrocytes, microglia, the vasculature, and the composition of the extracellular matrix (ECM). We will discuss how the regional differences in these elements surrounding OPCs might shape their phenotypic variability in normal and demyelinated states.

Sign in / Sign up

Export Citation Format

Share Document