Highlights • High quality MRI is very important in the diagnostic work-up of epilepsy. • VNS is increasingly used in the treatment of pharmacoresistant epilepsy. • MRI can be performed in ...VNS-patients under certain conditions. • Because of the resulting loss of image quality, subtle pathologies may be missed. • Image quality is adequate for detection and follow-up of ganglioglioma or PNH.
Chronic inflammatory demyelinating diseases of the CNS typically show a limited lesion size. However, extended lesions may appear with an atypical configuration. Large lesions with a diameter>2cm ...accompanied by tumor-like edema are entitled “tumefactive” and may occur in multiple sclerosis (MS) and other demyelinating diseases. Historically, differential diagnosis often requires histological analysis. Therefore, advanced imaging techniques are warranted to allow for a precise non-invasive diagnosis.
Cerebral sodium (23Na) MRI was recently described as a new method to investigate in vivo sodium accumulation. Indicating extended sodium levels in MS lesions, 23Na MRI is a promising differential diagnostic tool further elucidating the role of sodium in demyelinating lesions.
Repetitive 23Na MRI measurements in a MS patient with a tumefactive demyelinating lesion providing insight into the medium-term course of cerebral sodium levels.
23Na MRI depicts persistent lesional sodium accumulation after anti-inflammatory treatment and provides the opportunity of a non-invasive, in vivo analysis of sodium levels in inflammatory CNS lesions without need for contrast enhancing media. As a result of the extended dimension, tumefactive lesions may have an appropriate size for the analysis of inflammatory demyelination by 23Na MRI with sufficient resolution.
•23NaMRI provides information about cerebral sodium levels in-vivo.•In MS elevated cerebral sodium levels are correlated to inflammation.•23NaMRI shows persistent sodium accumulation in tumefactive lesions after treatment.
Abstract Background Chronic inflammatory demyelinating diseases of the CNS typically show a limited lesion size. However, extended lesions may appear with an atypical configuration. Large lesions ...with a diameter > 2 cm accompanied by tumor-like edema are entitled “tumefactive” and may occur in multiple sclerosis (MS) and other demyelinating diseases. Historically, differential diagnosis often requires histological analysis. Therefore, advanced imaging techniques are warranted to allow for a precise non-invasive diagnosis. Cerebral sodium (23 Na) MRI was recently described as a new method to investigate in vivo sodium accumulation. Indicating extended sodium levels in MS lesions,23 Na MRI is a promising differential diagnostic tool further elucidating the role of sodium in demyelinating lesions. Methods Repetitive23 Na MRI measurements in a MS patient with a tumefactive demyelinating lesion providing insight into the medium-term course of cerebral sodium levels. Results and conclusion23 Na MRI depicts persistent lesional sodium accumulation after anti-inflammatory treatment and provides the opportunity of a non-invasive, in vivo analysis of sodium levels in inflammatory CNS lesions without need for contrast enhancing media. As a result of the extended dimension, tumefactive lesions may have an appropriate size for the analysis of inflammatory demyelination by23 Na MRI with sufficient resolution.
To enable whole-brain quantitative CEST MRI at ultra-high magnetic field strengths (B
≥ 7T) within short acquisition times.
Multiple interleaved mode saturation (MIMOSA) was combined with fast ...online-customized (FOCUS) parallel transmission (pTx) excitation pulses and
correction to achieve homogenous whole-brain coverage. Examinations of 13 volunteers were performed on a 7T MRI system with 3 different types of pulse sequences: (1) saturation in circular polarized (CP) mode and CP mode readout, (2) MIMOSA and CP readout, and (3) MIMOSA and FOCUS readout. For comparison, the inverse magnetic transfer ratio metric for relayed nuclear Overhauser effect and amide proton transfer were calculated. To investigate the number of required acquisitions for a good
correction, 4 volunteers were measured with 6 different B
amplitudes. Finally, time point repeatability was investigated for 6 volunteers.
MIMOSA FOCUS sequence using
correction, with both single and multiple points, reduced inhomogeneity of the CEST contrasts around the occipital lobe and cerebellum. Results indicate that the most stable inter-subject coefficient of variation was achieved using the MIMOSA FOCUS sequence. Time point repeatability of MIMOSA FOCUS with single-point
correction showed a maximum coefficient of variation below 8% for 3 measurements in a single volunteer.
A combination of MIMOSA FOCUS with a single-point
correction can be used to achieve quantitative CEST measurements at ultra-high magnetic field strengths. Compared to previous
correction methods, acquisition time can be reduced as additional scans required for
correction can be omitted.
Abstract Background The X-linked creatine transporter deficiency (CRTD) caused by an SLC6A8 mutation represents the second most common cause of X-linked intellectual disability. The clinical ...phenotype ranges from mild to severe intellectual disability, epilepsy, short stature, poor language skills, and autism spectrum disorders. The objective of this study was to investigate phenotypic variability in the context of genotype, cerebral creatine concentration, and volumetric analysis in a family with CRTD. Patients and Methods The clinical phenotype and manifestations of epilepsy were assessed in a Caucasian family with CRTD. DNA sequencing and creatine metabolism analysis confirmed the diagnosis. Cerebral magnetic resonance imaging (cMRI) with voxel-based morphometry and magnetic resonance spectroscopy was performed in all family members. Results An SLC6A8 missense mutation (c.1169C>T; p.Pro390Leu, exon 8) was detected in four of five individuals. Both male siblings were hemizygous, the mother and the affected sister heterozygous for the mutation. Structural cMRI was normal, whereas voxel-based morphometry analysis showed reduced white matter volume below the first percentile of the reference population of 290 subjects in the more severely affected boy compared with family members and controls. Normalized creatine concentration differed significantly between the individuals ( P < 0.005). Conclusions There is a broad phenotypic variability in CRTD even in family members with the same mutation. Differences in mental development could be related to atrophy of the subcortical white matter.
Summary
Purpose: The objective of this study was to determine if levetiracetam (LEV) modulates brain γ‐aminobutyric acid (GABA) in patients with epilepsy.
Methods: Occipital GABA was assessed by ...protein magnetic resonance spectroscopy (1H‐MRS) in 16 patients with focal epilepsy at baseline and following the initiation of oral administration of LEV as monotherapy. Responder profiles were calculated as percentage of baseline seizure frequency. Alterations of GABA/Cr (creatine) of baseline measurements compared to GABA/Cr under LEV therapy were analyzed by Student’s t‐test for paired samples.
Results: After administration of LEV, partial seizure reduction (>50%) was noticed in 5 of 16 patients (31%; 7 of 16 (44%) patients turned out to be free of seizures. Patients with 50–100% seizure reduction under LEV titration were referred to as LEV responders. Of the 32 GABA spectra, only 22 (approximately 70%) yielded a result that met the criteria for spectral quality; therefore, GABA/Cr data from only seven patients were paired. A significant increase of GABA/Cr during titration with LEV was noted in patients responding to LEV (n = 5; p = 0.007). No differences in baseline GABA/Cr levels were detected between patients with and without previous antiepileptic treatment (p = 0.74).
Discussion: The increasing GABA/Cr levels under drug titration only in LEV‐responding epilepsy patients suggest a more complex and indirect influence of LEV on the GABAergic system.
SummaryPurpose:The objective of this study was to determine if levetiracetam (LEV) modulates brain g-aminobutyric acid (GABA) in patients with epilepsy.Methods:Occipital GABA was assessed by protein ...magnetic resonance spectroscopy (1H-MRS) in 16 patients with focal epilepsy at baseline and following the initiation of oral administration of LEV as monotherapy. Responder profiles were calculated as percentage of baseline seizure frequency. Alterations of GABA-Cr (creatine) of baseline measurements compared to GABA-Cr under LEV therapy were analyzed by Student's t-test for paired samples.Results:After administration of LEV, partial seizure reduction (>50%) was noticed in 5 of 16 patients (31%; 7 of 16 (44%) patients turned out to be free of seizures. Patients with 50-100% seizure reduction under LEV titration were referred to as LEV responders. Of the 32 GABA spectra, only 22 (approximately 70%) yielded a result that met the criteria for spectral quality; therefore, GABA-Cr data from only seven patients were paired. A significant increase of GABA-Cr during titration with LEV was noted in patients responding to LEV (n = 5; p = 0.007). No differences in baseline GABA-Cr levels were detected between patients with and without previous antiepileptic treatment (p = 0.74).Discussion:The increasing GABA-Cr levels under drug titration only in LEV-responding epilepsy patients suggest a more complex and indirect influence of LEV on the GABAergic system.
The objective of this study was to determine how metabolite values (total N-acetyl aspartate tNAA, glutamate plus glutamine Glx, total choline tCho, myoinositol mI, and total creatine tCr) vary ...across brain regions in healthy subjects. This study was implemented to create an internal reference database for patients with psychiatric disorders and epilepsy.
Using the multivoxel technique with a voxelwise phantom calibration on a 3-T magnetic resonance imaging scanner, metabolite levels of 29 healthy controls (13 men, 16 women; average age, 29 years) were obtained from the hippocampi, basal ganglia, insula cortex, cingulum, and precuneus. Additionally, gray and white matter metabolite values were obtained from the frontal and parietal lobes.
No significant effect of gender was noticed. The total magnitude of variation was greatest for Glx, followed by tNAA, mI, tCho, and tCr. Glx/tCr, Glx, and tCr were increased in gray matter, while tNAA/tCr, tCho/tCr, respectively tNAA and tCho, were elevated in white matter. These findings indicate (1) anterior-to-posterior increases of tNAA/tCr and Glx/tCr, respectively tNAA and Glx, along the midline in gray matter (cingulum); (2) increased tNAA/tCr, respectively tNAA, in white matter in the fiber tracts of the precentral region; (3) an accentuated anterior-to-posterior increase of tCr in the insula cortex; and (4) an anterior-to-posterior decrease of tCho/tCr and tCho in white matter.
There are significant metabolic differences within tissue types and within tissue types at different locations; therefore, the spectra and metabolite values presented should provide a useful internal reference for both clinical and research studies.
CEST suffers from two main problems long acquisitin times or restricted coverage as well as incoherent protocol settings. In this paper we give suggestions on how to optimise your protocol settings ...fro CEST and present one setting for APT CEST. To increase the coverage while keeping the acquisition time constant we suggest using a spatial temporal Compressed Sensing approach. Finally, 1.8mm isotropic whole brain APT CEST maps can be acquired in a little bit less than 2min with a fully integrated online reconstruction. This will pave the way to an even further clinical use of CEST.
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