Signal Intensity In White Matter Research Articles

Very-long T2-weighted imaging of the non-lesional brain tissue in multiple sclerosis patients.

The purpose of this study is to demonstrate that T2-weighted imaging with very long echo time (TE > 300 ms) can provide relevant information in neurodegenerative/inflammatory disorder. Twenty patients affected by relapsing-remitting multiple sclerosis with stable disease course underwent 1.5T 3D FLAIR, 3D T1-weighted, and a multi-echo sequence with 32 echoes (TE = 10-320 ms). Focal lesions (FL) were identified on FLAIR. T1-images were processed to segment deep gray matter (dGM), white matter (WM), FL sub-volumes with T1 hypo-intensity (T1FL), and dGM volumes (atrophy). Clinical-radiological parameters included Expanded Disability Status Scale (EDSS), disease duration, patient age, T1FL, and dGM atrophy. Correlation analysis was performed between the mean signal intensity (SI) computed on the non-lesional dGM and WM at different TE versus the clinical-radiological parameters. Multivariable linear regressions were fitted to the data to assess the association between the dependent variable EDSS and the independent variables obtained by T1FL lesion load and the mean SI of dGM and WM at the different TE. A clear trend is observed, with a systematic strengthening of the significance of the correlation at longer TE for all the relationships with the clinical-radiological parameters, becoming significant (p < 0.05) for EDSS, T1FL volumes, and dGM atrophy. Multivariable linear regressions show that at shorter TE, the SI of the T2-weighted sequences is not relevant for describing the EDSS variability while the T1FL volumes are relevant, and vice versa, at very-long TEs (around 300 ms); the SI of the T2-weighted sequences significantly (p < 0.05) describes the EDSS variability. By very long TE, the SI primarily originates from water with a T2 longer than 250 ms and/or free water, which may be arising from the perivascular space (PVS). Very-long T2-weighting might detect dilated PVS and represent an unexplored MR approach in neurofluid imaging of neurodegenerative/inflammatory diseases.

Temporal Changes on Postgadolinium MR Vessel Wall Imaging Captures Enhancement Kinetics of Intracranial Atherosclerotic Plaques and Aneurysms.

Analysis of vessel wall contrast kinetics (ie, wash-in/washout) is a promising method for the diagnosis and risk-stratification of intracranial atherosclerotic disease plaque (ICAD-P) and the intracranial aneurysm walls (IA-W). We used black-blood MR imaging or MR vessel wall imaging to evaluate the temporal relationship of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws compared with normal anatomic reference structures. Patients with ICAD-Ps or IAs who underwent MR vessel wall imaging with precontrast, early postcontrast (5-15 minutes), and delayed postcontrast (20-30 minutes) 3D T1-weighted TSE sequences were retrospectively studied. ROIs of a standardized diameter (2 mm) were used to measure the signal intensities of the cavernous sinus, pituitary infundibulum, temporalis muscle, and choroid plexus. Point ROIs were used for ICAD-Ps and IA-Ws. All ROI signal intensities were normalized to white matter signal intensity obtained using ROIs of 10-mm diameter. Measurements were acquired on precontrast, early postcontrast, and delayed postcontrast 3D T1 TSE sequences for each patient. Ten patients with 17 symptomatic ICAD-Ps and 30 patients with 34 IA-Ws were included and demonstrated persisting contrast uptake (P < .001) of 7.21% and 10.54% beyond the early phase (5-15 minutes postcontrast) and in the delayed phase (20-30 minutes postcontrast) on postcontrast MR vessel wall imaging. However, normal anatomic reference structures including the pituitary infundibulum and cavernous sinus demonstrated a paradoxical contrast washout in the delayed phase. In both ICAD-Ps and IA-Ws, the greatest percentage of quantitative enhancement (>70%-90%) occurred in the early phase of postcontrast imaging, consistent with the rapid contrast uptake kinetics of neurovascular pathology. Using standard MR vessel wall imaging techniques, our results demonstrate the effects of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws with extended accumulating enhancement into the delayed phase (> 15 minutes) as opposed to normal anatomic reference structures that conversely exhibit decreasing enhancement. Because these relative differences are used to assess qualitative patterns of ICAD-P and IA-W enhancement, our findings highlight the importance of standardizing acquisition time points and MR vessel wall imaging protocols to interpret pathologic enhancement for the risk stratification of cerebrovascular pathologies.

Effect of gadolinium contrast medium administration on susceptibility-weighted imaging of the canine brain.

Susceptibility-weighted imaging (SWI) is a gradient echo (GE) MRI sequence. Intravenous administration of gadolinium (Gd) may affect GE images, but its effect on SWI has not been investigated in veterinary medicine. This cross-sectional prospective study evaluated the effects of Gd on SWI. Seventy-one dogs that underwent brain MRI were included and distributed in two groups. Susceptibility-weighted imaging was performed pre- and postcontrast, obtained immediately after Gd administration (Group A: n=35) or delayed (Group B: n=36; median delay 19.9 min). Pre- and post-Gd SWI were analyzed for signal intensity changes in the lentiform nuclei of gray matter (GM), in the centrum semiovale of white matter (WM), and in brain lesions. No difference in GM signal intensity was identified in either group between pre- and postcontrast images (Group A, P=.395; Group B, P=.895). In group A, WM signal intensity was lower in pre- than post-Gd sequences (P=.019). Brain lesions were identified in 30/71 (41%) cases; the signal intensity of intracranial lesions was significantly lower in pre- than post-Gd images in both groups (P<.001); the number of lesions influenced the difference in signal intensity in group B (P=.043). Susceptibility artifacts did not change in appearance between pre- and postcontrast images in either the normal brain or in parenchymal lesions. In conclusion, Gd may modify the signal intensity of WM and brain lesions but does not affect the susceptibility artifacts and does not interfere with SWI interpretation.

Long-Term Disease Course of Pontocerebellar Hypoplasia Type 10

BackgroundPontocerebellar hypoplasia type 10 (PCH10) due to CLP1 gene mutations is characterized by structural brain anomalies, progressive microcephaly, severe intellectual and physical disabilities, and spasticity. In this follow-up study, evolution of phenotypic and neurological characteristics of patients with PCH10 is discussed. MethodsPhenotype, growth parameters, motor functions, developmental tests, spasticity assessments, functional independence assessments, electroencephalography (EEG), and brain magnetic resonance imaging (MRI) of 10 patients with PCH10 were monitored on separate examinations. Alterations were recorded. ResultsPatients were followed-up for an average of 2.83 years. The tone of the upper extremities was significantly higher than that of the lower extremities, according to Modified Ashworth Scale (MAS) values. Sixty percent of patients could sit unsupported; 20% achieved supported sitting initially but lost the ability during follow-up. Absence of grabbing or sitting was observed in 20% of patients. During follow-up, one person achieved supported sitting and one person achieved head holding. Only one patient was able to speak a few words. Cerebellar atrophy (two of 10), pons hypoplasia (four of 10), cortical atrophy (seven of 10), enlarged ventricles (10 of 10), thinning of the corpus callosum (10 of 10), hypomyelination (six of 10), and increased white matter signal intensity (six of 10) were the observed MRI findings. ConclusionsProgressive cerebral and cerebellar atrophy was demonstrated radiologically for the first time in a PCH10 cohort. It is of crucial importance to identify these patients promptly with the help of dysmorphic findings and spasticity being pronounced in the upper extremities. Furthermore, we note that phenotypic and neurological examination findings tend to change slightly over time.

Characterizing the association between complement-mediated TMA and cognitive dysfunction using MRI and neurocognitive assessment

AbstractComplement-mediated thrombotic microangiopathy (CM-TMA) is a rare, life-threatening thrombotic microangiopathy caused by a defect in the alternative complement pathway. It is associated with renal failure and acute encephalopathy, but long-term neurocognitive effects are uncertain. Using magnetic resonance imaging (MRI) and neurocognitive tests, we can further evaluate the long-term neurocognitive complications in CM-TMA and compare them with controls. In this study, we analyzed microstructural changes in the cerebral white matter and neurocognitive testing results of patients with CM-TMA. Seven adult patients with CM-TMA in remission and 6 healthy controls were included. All patients were treated with C5 complement blockade. They were followed-up for 12 months after study entry. All patients had consecutive MRI scans (standard-of-care and quantitative sequences) to assess for white matter changes and concurrent neurocognitive testing. Patients with CM-TMA had increased white matter signal intensity in most regions of the brain compared with controls. This was accompanied by increased depression and neurocognitive dysfunction (impaired concentration, short-term memory, and verbal memory). These findings were also present up to 12 months after the initial study visit. In summary, patients with previous CM-TMA were found to have significant, albeit nonspecific, cerebral white matter abnormalities, with impaired memory and concentration. Larger studies with longitudinal follow-up to assess neurocognitive complications in CM-TMA are required. This trial was registered at Clinical Trials Ontario (ctontario.ca; project ID: 1318).

Gray–white matter contrast reversal on T1-weighted spin-echo in postmortem brain

PurposeThe image contrast of postmortem magnetic resonance imaging (MRI) may differ from that of antemortem MRI because of circulator arrest, changes in postmortem tissue, and low-body-temperature scanning conditions. In fact, we have found that the signal intensity of white matter (WM) on T1-weighted spin-echo (T1WSE) images of the postmortem brain was lower than that of gray matter (GM), which resulted in image contrast reversal between GM and WM relative to the living brain. However, the reason for this phenomenon is unclear. Therefore, the aim of this study is to clarify the reason why image contrast reversal occurs between GM and WM of the postmortem brain. Materials and methodsTwenty-three corpses were included in the study (mean age, 60.6 years; range: 19–60 years; mean rectal temperature at scan, 6.9℃; range: 4–11℃). On a 1.5 T MRI system, postmortem T1W-SE MRI of the brain was conducted in the 23 corpses prior to medico-legal autopsy. Next, T1 and T2 of the GM and WM at the level of the basal ganglia were determined in the same participants using inversion recovery and multiple SE sequences, respectively. The proton density (PD) was also calculated from the T1 and T2 images (in the same slice). ResultsT1W-SE image contrast between the GM and WM of all postmortem brains was inverted relative to the living brain. T1 (579 ms in GM and 307 ms in WM) and PD (64 in GM and 44 in WM) of the postmortem brain decreased compared with the living brain. While T1 of WM/GM remained below 1 even postmortem, the PD of WM/GM decreased. T2 (110 ms in GM and 98 ms in WM) of the postmortem brain did not differ from the living brain. ConclusionThe decrease in PD of WM/GM in the postmortem brain may be the major driver of contrast reversal between the GM and WM relative to the living brain.

The impact of paramagnetic rim lesions on cortical thickness and gray to white matter contrast in relapsing-remitting multiple sclerosis.

Paramagnetic rim lesions (PRLs) on susceptibility magnetic resonance sequences have been suggested as an imaging marker of disease progression in multiple sclerosis. This retrospective cross-sectional study aimed to investigate the impact of PRLs on cortical thickness and gray matter (GM) to white matter (WM) contrast in relapsing-remitting multiple sclerosis (RRMS). A total of 82 RRMS patients (40 patients with at least 1 PRL and 42 patients without PRL) and 43 healthy controls (HC) were included in this study. The T1-weighted images (T1WI) were processed with the FreeSurfer pipeline. GM to WM signal intensity ratio (GWR) was obtained from T1WI by dividing the GM signal intensity by the WM signal intensity for each vertex. Group differences in cortical thickness and GWR were tested on reconstructed cortical surface. Compared to HC, patients with PRL had thinner mean cortical thickness (P<0.001), higher mean GWR (P=0.001), and lower brain structure volumes (cortex volume, P=0.001; WM volume, P<0.001; deep GM volume, P<0.001). Vertex-based analysis found significant cortical thinning in several regions and increased GWR in a wider range of regions in patients with PRL. The two types of clusters had both overlapping regions and independent regions. However, in patients without PRL, only a few regions showed significant cortical thickness changes. Correlation analysis found that in patients with PRL, only PRL volume showed a significant negative correlation with mean cortical thickness (P=0.048), and PRL volume and count, non-PRL count, and total lesion volume were significantly and positively correlated with mean GWR (P<0.05). There were significant changes in cortical thickness, GWR, and brain structure volume in RRMS patients with PRL that may contribute to further understanding of the pathological mechanisms underlying neurological tissue damage.

Decay in Entorhinal White Matter/Gray Matter contrast in Alzheimer’s Disease Patients is reduced by 40Hz sensory stimulation

AbstractBackgroundPrevious research has shown that white matter (WM) and gray matter (GM) tissues exhibit regionally selective pathological changes in Alzheimer’s disease (AD). The contrast between WM and GM signal intensities (WM/GM contrast) measured by magnetic resonance imaging (MRI) has previously been proposed as a method for quantifying these changes. It has been shown that WM/GM contrast can provide sensitive, independent, and distinct information about pathologies compared with traditional MRI measures. Studies have also shown, including entorhinal WM/GM contrast to traditional MRI measures resulted in better discrimination between AD and controls. We previously demonstrated that 40Hz auditory‐visual stimulation therapy reduced WM atrophy and myelin loss in AD patients. The present study quantified the effects of the therapy on the WM/GM contrast in the entorhinal region.MethodThis study used neuroimaging data from Overture, a phase I/II randomized, placebo‐controlled feasibility study (NCT03556280) in patients on the AD spectrum. Treatment group received 40Hz gamma sensory stimulation daily at home for six months, whereas placebo group received sham stimulation. Structural MRI was obtained at baseline, month 3 and month 6 visits using 1.5 Tesla scanner. FreeSurfer was used to process T1 MRI including entorhinal parcellation and cortical reconstructions for 38 participants (66% Treatment, 34% Placebo). For each vertex, WM signal intensity (WMI) is sampled at 1mm below, and GM signal intensity (GMI) is sampled at 30% of cortical thickness above the WM/GM border. WM/GM contrast was calculated as 100*(WMI–GMI)/(0.5*(WMI+GMI)) %. Bayesian linear mixed effects modeling was used to model changes in WM/GM contrast in the entorhinal region.ResultFollowing 6 months of treatment, we observed that the treatment group demonstrated 0.06±0.99% decrease and the placebo group demonstrated 1.26±1.04% decrease in WM/GM contrast (p&lt;0.022).ConclusionWe found that six months of 40Hz gamma sensory therapy reduced the decline in WM/GM contrast in the entorhinal region. Since WM/GM contrast is associated with AD severity, and the entorhinal region is of particular interest in the early stages of AD, early intervention of the therapy may result in enhanced tissue preservation and reduced neurological damage.

Gray to White Matter Signal Ratio as a novel biomarker of neurodegeneration in Alzheimer’s disease

AbstractBackgroundAlzheimer’s disease (AD) is characterized neuropathologically by ß‐amyloid (Aß) plaques, hyperphosphorylated tau neurofibrillary tangles, and neurodegeneration which leads to a phenotypically heterogeneous cognitive‐behavioral dementia syndrome. Our understanding of how these neuropathological and neurodegeneration biomarkers relate to each other is still evolving. A relatively new approach to measuring structural brain change, gray matter to white matter signal intensity ratio (GWR), quantifies the signal contrast between these tissue compartments, and has emerged as a promising marker of AD‐related neurodegeneration. We sought to validate GWR as a novel MRI biomarker of neurodegeneration.MethodTwenty‐nine amyloid‐, tau‐, and neurodegeneration positive patients with atypical syndromes of AD (16 Posterior Cortical Atrophy, 10 logopenic variant of Primary Progressive Aphasia, and 3 Amnestic Dysexecutive phenotype) and 24 amyloid‐negative control participants underwent structural MRI, 11C‐Pittsburgh Compound B (PiB) PET, and 18F‐flortaucipir (FTP) PET scans. Whole‐cortex vertex‐wise general linear models (GLM) were created to identify areas of the cerebral cortex where AD patients showed abnormal signal in each modality, and Pearson’s correlation coefficients were computed to examine the strength of bivariate associations between each pair of modalities at the group level. We then constructed linear mixed‐effects models to test the relative contribution of each non‐FTP modality to explaining the variance in regional FTP uptake.ResultWe found that GWR was associated with cortical thickness, tau PET, and amyloid PET, with GWR showing a larger magnitude of abnormality than cortical thickness. We also found that combining GWR, cortical thickness, and amyloid PET better explained observed tau PET signal than using these modalities alone, suggesting that the three imaging biomarkers contribute independently and synergistically to explaining the variance in the distribution of tau pathology.ConclusionWe conclude that GWR is a uniquely sensitive in vivo marker of neurodegenerative change that reflects pathological mechanisms which may occur prior to cortical atrophy. By using all of these imaging biomarkers of AD together, we may be better able to capture, and possibly predict, AD neuropathologic changes in vivo, which we hope will ultimately contribute to better endpoints to evaluate the efficacy of therapeutic interventions as we move toward an era of disease‐modifying treatments for this devastating disease.

Cortical gray to white matter signal intensity ratio as a sign of neurodegeneration and cognition independent of β-amyloid in dementia.

Cortical gray to white matter signal intensity ratio (GWR) measured from T1-weighted magnetic resonance (MR) images was associated with neurodegeneration and dementia. We characterized topological patterns of GWR during AD pathogenesis and investigated its association with cognitive decline. The study included a cross-sectional dataset and a longitudinal dataset. The cross-sectional dataset included 60 cognitively healthy controls, 61 mild cognitive impairment (MCI), and 63 patients with dementia. The longitudinal dataset included 26 participants who progressed from cognitively normal to dementia and 26 controls that remained cognitively normal. GWR was compared across the cross-sectional groups, adjusted for amyloid PET. The correlation between GWR and cognition performance was also evaluated. The longitudinal dataset was used to investigate GWR alteration during the AD pathogenesis. Dementia with β-amyloid deposition group exhibited the largest area of increased GWR, followed by MCI with β-amyloid deposition, MCI without β-amyloid deposition, and controls. The spatial pattern of GWR-increased regions was not influenced by β-amyloid deposits. Correlation between regional GWR alteration and cognitive decline was only detected among individuals with β-amyloid deposition. GWR showed positive correlation with tau PET in the left supramarginal, lateral occipital gyrus, and right middle frontal cortex. The longitudinal study showed that GWR increased around the fusiform, inferior/superior temporal lobe, and entorhinal cortex in MCI and progressed to larger cortical regions after progression to AD. The spatial pattern of GWR-increased regions was independent of β-amyloid deposits but overlapped with tauopathy. The GWR can serve as a promising biomarker of neurodegeneration in AD.

Double inversion recovery MRI of subcortical band heterotopia and its variations.

Subcortical band heterotopia (SBH) is a malformation of cortical development diagnosed via MRI. Currently, patients with SBH are classified according to Di Donato's classification. We aimed to show a variation of SBH and the usefulness of double inversion recovery (DIR) images. We retrospectively reviewed the MRI findings of 28 patients with SBH. The patients were classified according to Donato's classification by using conventional MR images, and their DIR findings were reviewed. Of 28 patients, 20 were grade 1 and 8 were grade 2 according to Di Donato's classification. In 15 of 28 patients, the following four types of atypical MRI findings were detected: asymmetry distribution (four cases), coexistence of thin and thick SBH (five cases), and DIR faint abnormal signal intensity in subcortical white matter (five cases) and in deep white matter (five cases). The latter two types were detected on DIR alone and have not been reported. Additionally, these were identified only in the mild group (Di Donato's classification 1-1 or 1-2). DIR is a useful MRI sequence for detecting faint white matter signal abnormalities, and it can aid in the accurate classification of SBH and identification of its variations, which may reflect the pathology of SBH.

Stroke-like presentation of acute toxic leukoencephalopathy due to capecitabine treatment with extensive intramyelinic edema.

Stroke-like presentation of acute toxic leukoencephalopathy due to capecitabine treatment with extensive intramyelinic edema.

Diagnostic value of contrast-enhanced 3D FLAIR sequence in acute optic neuritis.

Contrast-enhanced fluid-attenuated inversion recovery (FLAIR) sequence of the brain has the potential for detecting optic nerve abnormality. This study aimed to compare the diagnostic value of whole-brain contrast-enhanced three-dimensional FLAIR with fat suppression (CE 3D FLAIR FS) sequence in detecting acute optic neuritis to dedicated orbit MRI and clinical diagnosis. Twenty-two patients with acute optic neuritis who underwent whole-brain CE-3D-FLAIR FS and dedicated orbit MRI were retrospectively included. The hypersignal FLAIR of the optic nerve on whole-brain CE-3D-FLAIR FS, enhancement, and hypersignal T2W on orbit images were assessed. The optic nerve to frontal white matter signal intensity ratio on CE-FLAIR FS was calculated as maximum signal intensity ratio (SIR) and mean SIR. Twenty-six hypersignals of optic nerves were found on CE-FLAIR FS from 30 pathologic nerves. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CE FLAIR FS brain and dedicated orbital images for diagnosing acute optic neuritis were 77%, 93%, 96%, 65%, and 82% and 83%, 93%, 96%, 72%, and 86%, respectively. Optic nerve to frontal white matter SIR of the affected optic nerves was higher than that of normal optic nerves. Using a cutoff maximum SIR of 1.24 and cutoff mean SIR of 1.16, the sensitivity, specificity, PPV, NPV, and accuracy were 93%, 86%, 93%, 80%, and 89% and 93%, 86%, 93%, 86%, and 91%, respectively. The hypersignal of the optic nerve on whole-brain CE 3D FLAIR FS sequence has qualitative and quantitative diagnostic potential in patients with acute optic neuritis.

Light without TORCH: Periventricular Haemorrhage and Group B Streptococcal Meningitis in a Neonate

Post-infectious hydrocephalus is a common entity needing attention of paediatricians and neurosurgeons. Periventricular Haemorrhage (PVH) affects both preterm and term babies. Risk factors include male gender, short gestation, labour and vaginal delivery. Congenital infections such as Toxoplasma and CMV are associated with hydrocephalus and intracranial calcification. We present an unusual association of Group B Streptococcal infection with periventricular haemorrhage. A Caucasian female was born at 37 weeks gestation by normal vaginal delivery. Birth weight was 2.72kg and OFC was 33cm (50th centile). There were no antenatal problems or maternal infections. On day 2 of life, the patient presented with unusual cry, lethargy and reduced feeding. Group B Streptococcal meningitic septicaemia was confirmed with positive CSF and blood cultures. At 7 weeks, she presented with a two-week history of increasing head circumference. Ventriculo Peritoneal (VP) shunt was inserted for post-infectious hydrocephalus. There was difficulty in waking the patient up post-operatively and subsequent CT Brain showed the presence of multiple high attenuation foci in the periventricular region suggestive of haemorrhage or calcification. MR imaging confirmed numerous foci of abnormal signal intensity in the periventricular white matter, most likely blood products. To our knowledge, this is the first report of an association between Group B Streptococcal meningitis and PVH.

Gray to white matter signal ratio as a novel biomarker of neurodegeneration in Alzheimer’s disease

Alzheimer’s disease (AD) is characterized neuropathologically by β-amyloid (Aβ) plaques, hyperphosphorylated tau neurofibrillary tangles, and neurodegeneration, which lead to a phenotypically heterogeneous cognitive-behavioral dementia syndrome. Our understanding of how these neuropathological and neurodegeneration biomarkers relate to each other is still evolving. A relatively new approach to measuring structural brain change, gray matter to white matter signal intensity ratio (GWR), quantifies the signal contrast between these tissue compartments, and has emerged as a promising marker of AD-related neurodegeneration. We sought to validate GWR as a novel MRI biomarker of neurodegeneration in 29 biomarker positive individuals across the atypical syndromic spectrum of AD. Bivariate correlation analyses revealed that GWR was associated with cortical thickness, tau PET, and amyloid PET, with GWR showing a larger magnitude of abnormality than cortical thickness. We also found that combining GWR, cortical thickness, and amyloid PET better explained observed tau PET signal than using these modalities alone, suggesting that the three imaging biomarkers contribute independently and synergistically to explaining the variance in the distribution of tau pathology. We conclude that GWR is a uniquely sensitive in vivo marker of neurodegenerative change that reflects pathological mechanisms which may occur prior to cortical atrophy. By using all of these imaging biomarkers of AD together, we may be better able to capture, and possibly predict, AD neuropathologic changes in vivo. We hope that such an approach will ultimately contribute to better endpoints to evaluate the efficacy of therapeutic interventions as we move toward an era of disease-modifying treatments for this devastating disease.

A-161 Neuropsychological Findings and Atypical Motoric Features Associated with Hashimoto Encephalopathy in a 52-year-old Male

Abstract Objective: Hashimoto encephalopathy (HE) is a rare neurological condition with pathophysiology associated with elevated autoimmune anti-thyroid antibodies. The condition, associated with Hashimoto’s thyroiditis, is found more commonly in women. Clinical presentations of HE vary significantly, with cognitive deficit and generalized seizures as the most prominent manifestations. While there is robust literature illustrating HE in female populations, literature on HE in male patients, particularly with dominant motoric features, remains limited. Methods: A 52-year-old, right-handed, Caucasian male presented for evaluation reporting difficulties with short-term memory, word-finding, disorientation, and motor deficits. The patient exhibited significant motor symptoms including myotonia, micrographia, fasciculations and paresthesias, phantosmia, and myoclonic jerking, beginning in 2017 with progressive decline. Relevant medical history includes Hashimoto thyroiditis (2021), focal temporal EEG abnormalities (2021), dystonia (2021), and migraines. Prior to presenting concerns, the patient was otherwise generally healthy. Neuroimaging (MRI) revealed increased signal intensity in the subcortical white matter of the right frontal lobe. He was dependent in several instrumental activities of daily living. Results: His premorbid baseline was estimated to be in the average range. His neurocognitive profile was marked by mild impairments in immediate and delayed verbal memory and recognition paradigms, whereas he demonstrated moderate impairments in processing speed and motor functioning. Conculsion: Taken together, his neurocognitive profile, clinical history, and functional independence are consistent with the clinical presentation of HE. His cognitive deficits and epileptiform activity are consistent with prominent manifestations of HE, whereas his pronounced motoric features are seemingly aberrant in HE. Furthermore, post-steroidal treatment revealed increased cognitive proficiency on a single mental status examination.

Universal pulses for homogeneous excitation using single channel coils

PurposeUniversal Pulses (UPs) are excitation pulses that reduce the flip angle inhomogeneity in high field MRI systems without subject-specific optimization, originally developed for parallel transmit (PTX) systems at 7 T. We investigated the potential benefits of UPs for single channel (SC) transmit systems at 3 T, which are widely used for clinical and research imaging, and for which flip angle inhomogeneity can still be problematic. MethodsSC-UPs were designed using a spiral nonselective k-space trajectory for brain imaging at 3 T using transmit field maps (B1+) and off-resonance maps (B0) acquired on two different scanner types: a ‘standard’ single channel transmit system and a system with a PTX body coil.The effect of training group size was investigated using data (200 subjects) from the standard system. The PTX system was used to compare SC-UPs to PTX-UPs (15 subjects). In two additional subjects, prospective imaging using SC-UP was studied. ResultsAverage flip angle homogeneity error fell from 9.5 ± 0.5 % for ‘default’ excitation to 3.0 ± 0.6 % using SC-UPs trained over 50 subjects. Performance of the UPs was found to steadily improve as training group size increased, but stabilized after ~15 subjects.On the PTX-enabled system, SC-UPs again outperformed default excitation in simulations (4.8 ± 0.6 % error versus 10.6 ± 0.8 % respectively) though greater homogenization could be achieved with PTX-UPs (3.9 ± 0.6 %) and personalized pulses (SC-PP 3.6 ± 1.0 %, PTX-PP 2.9 ± 0.6 %).MP-RAGE imaging using SC-UP resulted in greater separation between grey and white matter signal intensities than default excitation. ConclusionsSC-UPs can improve excitation homogeneity in standard 3 T systems without further calibration and could be used instead of a default excitation pulse for nonselective neuroimaging at 3 T.

Magnetic resonance imaging findings of two cases with West syndrome and hypomelanosis of Ito with hemimegalencephaly: a report of two cases

BackgroundHemimegalencephaly is an unusual congenital non-familial malformation of the brain which is characterized by enlargement of the whole or part of one hemisphere due to neural proliferation and dysfunction in the cell migration. The brain stem and cerebellum may also be involved. There are also the common cortical malformation, unusual white matter proliferation, gliosis, and abnormal myelination in hemimegalencephaly. In addition, structural brain abnormalities like atrophy/hypertrophy, demyelination, gliosis, increased thickness of the cortical grey matter, increase signal intensity in the subcortical white matter, abnormal gyral patterns, blurring of the grey-white matter transition, and hamartomatous aspect can be observed on magnetic resonance imaging.Case presentationTwo patients who underwent brain magnetic resonance imaging because of West syndrome and hypomelanosis of Ito were diagnosed as hemimegalencephaly. The first case was a 9-day-old male patient initially diagnosed with West syndrome. On the brain magnetic resonance imaging performed for epilepsy, right total hemimegalencephaly, diffuse polymicrogyria, and heterotopic grey matter foci on the right hemisphere were observed. In addition, right cerebellar dysgenesis, upward angulation in the lateral ventricle's anterior horn, and colpocephalic dilatation in the posterior horn were evident. The second case was a 2-year-old female patient with hypomelanosis of Ito disease. The main reason for her parents' hospital visit was the shortness of the right leg. Initial examination showed the hypopigmented lesions on the right side and hemihypertrophy in the left leg. Brain magnetic resonance imaging revealed mild hemimegalencephaly in the right cerebral hemisphere, T1-weighted isointense, T2-weighted hyperintense white matter lesions extending from the basal ganglia to the ventricular body and the periventricular fronto-parieto-occipital white matter, and dilatation of the lateral ventricle.ConclusionsHemimegalencephaly is a rare condition which may accompany syndromic cases with epilepsy or neurocutaneous disease. Brain magnetic resonance imaging should be performed in patients with a suspicious medical history in order to make the correct diagnosis of hemimegalencephaly and to determine the severity of brain involvement, if any.

Optimization of magnetization transfer contrast for EPI FLAIR brain imaging.

To evaluate the impact of magnetization transfer (MT) on brain tissue contrast in turbo-spin-echo (TSE) and EPI fluid-attenuated inversion recovery (FLAIR) images, and to optimize an MT-prepared EPI FLAIR pulse sequence to match the tissue contrast of a clinical reference TSE FLAIR protocol. Five healthy volunteers underwent 3T brain MRI, including single slice TSE FLAIR, multi-slice TSE FLAIR, EPI FLAIR without MT-preparation, and MT-prepared EPI FLAIR with variations of the MT-preparation parameters, including number of preparation pulses, pulse amplitude, and resonance offset. Automated co-registration and gray matter (GM) versus white matter (WM) segmentation was performed using a T1-MPRAGE acquisition, and the GM versus WM signal intensity ratio (contrast ratio) was calculated for each FLAIR acquisition. Without MT preparation, EPI FLAIR showed poor tissue contrast (contrast ratio = 0.98), as did single slice TSE FLAIR. Multi-slice TSE FLAIR provided high tissue contrast (contrast ratio = 1.14). MT-prepared EPI FLAIR closely approximated the contrast of the multi-slice TSE FLAIR images for two combinations of the MT-preparation parameters (contrast ratio = 1.14). Optimized MT-prepared EPI FLAIR provided a 50% reduction in scan time compared to the reference TSE FLAIR acquisition. Optimized MT-prepared EPI FLAIR provides comparable brain tissue contrast to the multi-slice TSE FLAIR images used in clinical practice.

Cortical Gray to White Matter Signal Intensity Ratio as an Early Sign of Cognitive Decline in Alzheimer's Dementia and Mild Cognitive Impairment

Cortical Gray to White Matter Signal Intensity Ratio as an Early Sign of Cognitive Decline in Alzheimer's Dementia and Mild Cognitive Impairment