Simultaneous proton density, T
            1
            , T
            2
            , and flip‐angle mapping of the brain at 7 T using multiparametric 3D SSFP imaging and parallel‐transmission universal pulses

Purpose: To compare the detectability of small experimental intracranial haemorrhages on MR imaging at 0.5 T and 1.5 T, from hyperacute to subacute stages. Material and Methods: 1 ml of autologous blood was injected into the brain of 15 rabbits to create intraparenchymal haematomas. Since the blood partially escaped into the cerebrospinal fluid (CSF) spaces, detectability of subarachnoid and intraventricular blood was also evaluated. MR imaging at 0.5 T and at 1.5 T was repeated up to 14 days, including T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. The last MR investigation was compared to the formalin-fixed brain sections in 7 animals. Results: The intraparenchymal haematomas were best revealed with T2*-w GE sequences, with 100% of sensitivity at 1.5 T and 90–95% at 0.5 T. Blood in the CSF spaces was significantly ( p < 0.05) better detected at 1.5 T with T2*-w GE sequences and detected best during the first 2 days. The next most sensitive sequence for intracranial blood was FLAIR. SE sequences were rather insensitive. Conclusion: 1.5 T equipment is superior to 0.5 T in the detection of intracranial haemorrhages from acute to subacute stages. T2*-w GE sequences account for this result but other sequences are also needed for a complete examination.

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Spinal cord grey matter lesions in multiple sclerosis detected by post-mortem high field MR imaging

Multiple Sclerosis Journal ◽

10.1177/1352458508096876 ◽

2008 ◽

Vol 15 (2) ◽

pp. 180-188 ◽

Cited By ~ 49

Author(s):

CP Gilmore ◽

JJG Geurts ◽

N Evangelou ◽

JCJ Bot ◽

RA van Schijndel ◽

...

Keyword(s):

Spinal Cord ◽

White Matter ◽

Mr Imaging ◽

High Field ◽

Grey Matter ◽

Great Majority ◽

Proton Density ◽

Post Mortem ◽

Mr Images ◽

The Brain

Background Post-mortem studies demonstrate extensive grey matter demyelination in MS, both in the brain and in the spinal cord. However the clinical significance of these plaques is unclear, largely because they are grossly underestimated by MR imaging at conventional field strengths. Indeed post-mortem MR studies suggest the great majority of lesions in the cerebral cortex go undetected, even when performed at high field. Similar studies have not been performed using post-mortem spinal cord material. Aim To assess the sensitivity of high field post-mortem MRI for detecting grey matter lesions in the spinal cord in MS. Methods Autopsy material was obtained from 11 MS cases and 2 controls. Proton Density-weighted images of this formalin-fixed material were acquired at 4.7Tesla before the tissue was sectioned and stained for Myelin Basic Protein. Both the tissue sections and the MR images were scored for grey matter and white matter plaques, with the readers of the MR images being blinded to the histopathology results. Results Our results indicate that post-mortem imaging at 4.7Tesla is highly sensitive for cord lesions, detecting 87% of white matter lesions and 73% of grey matter lesions. The MR changes were highly specific for demyelination, with all lesions scored on MRI corresponding to areas of demyelination. Conclusion Our work suggests that spinal cord grey matter lesions may be detected on MRI more readily than GM lesions in the brain, making the cord a promising site to study the functional consequences of grey matter demyelination in MS.

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A finite element model for predicting the distribution of drugs delivered intracranially to the brain

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.273.5.r1810 ◽

1997 ◽

Vol 273 (5) ◽

pp. R1810-R1821 ◽

Cited By ~ 25

Author(s):

S. Kalyanasundaram ◽

V. D. Calhoun ◽

K. W. Leong

Keyword(s):

Drug Delivery ◽

Finite Element ◽

Spin Echo ◽

Interleukin 2 ◽

Chemical Species ◽

Transport Processes ◽

Proton Density ◽

Clear Understanding ◽

Tissue Properties ◽

The Brain

Drug therapy to the central nervous system is complicated by the presence of the blood-brain barrier. The development of new drug delivery techniques to overcome this obstacle will be aided by a clear understanding of the transport processes in the brain. A rigorous theoretical framework of the transport of drugs delivered locally to the parenchyma has been developed using the finite element method. Magnetic resonance imaging has been used to track the transport of paramagnetic contrast markers in the brain. The information obtained by postprocessing spin-echo, T1-weighted, and proton density images has been used to refine the mathematical model that includes realistic brain geometry and salient anatomic features and allows for two-dimensional transport of chemical species, including both diffusive and convective contributions. In addition, the effects of regional differences in tissue properties, ventricular boundary, and edema on the transport have been considered. The model has been used to predict transport of interleukin-2 in the brain and study the major determinants of transport, at both early and late times after drug delivery.

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Quantitative T 1 and proton density mapping with direct calculation of radiofrequency coil transmit and receive profiles from two-point variable flip angle data

NMR in Biomedicine ◽

10.1002/nbm.3460 ◽

2016 ◽

Vol 29 (3) ◽

pp. 349-360 ◽

Cited By ~ 16

Author(s):

Simon Baudrexel ◽

Sarah C. Reitz ◽

Stephanie Hof ◽

René-Maxime Gracien ◽

Vinzenz Fleischer ◽

...

Keyword(s):

Direct Calculation ◽

Flip Angle ◽

Proton Density ◽

Variable Flip Angle ◽

Density Mapping ◽

Radiofrequency Coil ◽

Angle Data

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Multiparametric mapping in post-mortem perinatal MRI: a feasibility study

British Journal of Radiology ◽

10.1259/bjr.20190952 ◽

2020 ◽

Vol 93 (1111) ◽

pp. 20190952

Author(s):

Amy R McDowell ◽

Susan C Shelmerdine ◽

Sara Lorio ◽

Wendy Norman ◽

Rod Jones ◽

...

Keyword(s):

Flip Angle ◽

Whole Body ◽

Proton Density ◽

Single Shot ◽

Post Mortem ◽

Variable Flip Angle ◽

High Quality ◽

Isotropic Resolution ◽

Tissue Contrast ◽

Magnetic Transfer

Objectives: To demonstrate feasibility of a 3 T multiparametric mapping (MPM) quantitative pipeline for perinatal post-mortem MR (PMMR) imaging. Methods: Whole body quantitative PMMR imaging was acquired in four cases, mean gestational age 34 weeks, range (29–38 weeks) on a 3 T Siemens Prisma scanner. A multicontrast protocol yielded proton density, T1 and magnetic transfer (MT) weighted multi-echo images obtained from variable flip angle (FA) 3D fast low angle single-shot (FLASH) acquisitions, radiofrequency transmit ﬁeld map and one B0 ﬁeld map alongside four MT weighted acquisitions with saturation pulses of 180, 220, 260 and 300 degrees were acquired, all at 1 mm isotropic resolution. Results: Whole body MPM was achievable in all four foetuses, with R1, R2*, PD and MT maps reconstructed from a single protocol. Multiparametric maps were of high quality and show good tissue contrast, especially the MT maps. Conclusion: MPM is a feasible technique in a perinatal post-mortem setting, which may allow quantification of post-mortem change, prior to being evaluated in a clinical setting. Advances in knowledge: We have shown that the MPM sequence is feasible in PMMR imaging and shown the potential of MT imaging in this setting.

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Nuclear Magnetic Resonance (NMR) II. Imaging in Dementia

The British Journal of Psychiatry ◽

10.1192/bjp.146.1.31 ◽

1985 ◽

Vol 146 (1) ◽

pp. 31-35 ◽

Cited By ~ 31

Author(s):

J. A. O. Besson ◽

F. M. Corrigan ◽

E. Iljon Foreman ◽

L. M. Eastwood ◽

F. W. Smith ◽

...

Keyword(s):

Senile Dementia ◽

Lattice Relaxation ◽

Lattice Relaxation Time ◽

Spin Lattice Relaxation ◽

Proton Density ◽

Alzheimer Type ◽

Spin Lattice ◽

Nmr Parameters ◽

Severity Of Dementia ◽

The Brain

SummaryProton NMR imaging of the brain is rapidly becoming established as a useful investigative tool in medicine. This paper examines the usefulness of the NMR parameters—spin-lattice relaxation time (T1) and proton density (PD)—in differentiating groups of patients with senile dementia of Alzheimer type (SDAT) and multi-infarct dementia (MID) from each other, and from elderly controls. T1 values increase with severity of dementia. NMR parameters may also be of use in localising regions of brain damage.

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