Inversion Recovery Magnetic Resonance Imaging Research Articles

Dark Rims: Novel Sequence Enhances Diagnostic Specificity in Multiple Sclerosis.

The 2010 McDonald criteria are designed to sensitively detect MS; however, the low specificity of these criteria can occasionally lead to the misdiagnosis of MS. The purpose of this study was to determine whether a novel double inversion recovery MR imaging technique has the potential to increase the specificity of diagnostic criteria distinguishing MS from non-MS white matter lesions. This was a cross-sectional observational study. MR imaging data were acquired between 2011 and 2016. A novel double inversion recovery sequence that suppresses CSF and GM signal was used (GM-double inversion recovery). We compared WM lesions in a group of patients with multiple sclerosis and in a second group of positive controls with white matter lesions who did not have a diagnosis of MS. The presence of a rim on the GM-double inversion recovery MR imaging sequence was combined with the 2001 and 2010 McDonald disseminated-in-space criteria. Multiple MR imaging markers, including lesion location, size, and the presence of a rim, were compared between groups as well as a quantitative measure of lesion T1 hypointensity. MR images from 107 patients with relapsing-remitting MS (median age, 32 years) and 36 positive control (median age, 39 years) subjects were analyzed. No significant differences were found in age and sex. In patients with MS, 1120/3211 lesions (35%) had a rim on GM-double inversion recovery; the positive control group had only 9/893 rim lesions (1%). Rims were associated with a decrease in the lesion T1 ratio. Using the 2010 MR imaging criteria plus the presence of rims on GM-double inversion recovery, we achieved 78% and 97% specificity in subjects with ≥1 and ≥2 rim lesions, respectively. The addition of a novel GM-double inversion recovery technique enhanced specificity for diagnosing MS compared with established MR imaging criteria.

Clinical features and imaging characteristics of Meniere's disease verified by intravenous gadolinium contrast-enhanced magnetic resonance imaging

Objective: To analyze the clinical features and imaging characteristics of Meniere's disease (MD)verified by intravenous gadolinium contrast-enhanced magnetic resonance imaging(MRI). Methods: A total of 174 patients with Meniere's disease were involved in this study between March 2016 and October 2017. All of them underwent 3D-fluid attenuated inversion recovery (FLAIR) MRI and presented endolymphatic hydrops and clinical characteristics of suspected Meniere's disease. The clinical characteristics, the grades of endolymphatic hydrops (EH) using Nakashima grading standard were analyzed, and the correlation between grade and clinical features was evaluated. Results: There were totally 174 patients (88 males, 86 females), with the age of 7-83 years [mean age of (51.0±15.0)] years. Age of onset and disease course was 7-83 years [mean age of (44.6±16.6) years], 36.0 (12.0, 111.0) months (from 2 days to 70 years), respectively. EH was found in all the patients, and 169 cases (97.1%) manifested as modest or severe hydrops. Among the 174 patients, 139 cases (79.9%) presented unilateral EH, and 35 cases (20.1%) presented bilateral EH. The degree of EH in the latter was more serious than the former. For 174 patients, clinical characteristics were inconsistent, which was not in accord with the existing diagnostic criteria. Furthermore, there was a correlation between degree of hydrops and degree of hearing loss (P<0.05). Conclusions: EH in Meniere's disease can be measured objectively by intravenous gadolinium contrast-enhanced MRI. Clinical characteristics in MD verified by EH are not accordant with the existing criteria, which means the significance of EH in diagnosis of MD. Moreover, there's a correlation between degree and distribution of hydrops and degree of hearing loss.

Hippocampal subfield segmentation in temporal lobe epilepsy: Relation to outcomes.

ObjectiveTo investigate the clinical and surgical outcome correlates of preoperative hippocampal subfield volumes in patients with refractory temporal lobe epilepsy (TLE) using a new magnetic resonance imaging (MRI) multisequence segmentation technique.MethodsWe recruited 106 patients with TLE and hippocampal sclerosis (HS) who underwent conventional T1‐weighted and T2 short TI inversion recovery MRI. An automated hippocampal segmentation algorithm was used to identify twelve subfields in each hippocampus. A total of 76 patients underwent amygdalohippocampectomy and postoperative seizure outcome assessment using the standardized ILAE classification. Semiquantitative hippocampal internal architecture (HIA) ratings were correlated with hippocampal subfield volumes.ResultsPatients with left TLE had smaller volumes of the contralateral presubiculum and hippocampus‐amygdala transition area compared to those with right TLE. Patients with right TLE had reduced contralateral hippocampal tail volumes and improved outcomes. In all patients, there were no significant relationships between hippocampal subfield volumes and clinical variables such as duration and age at onset of epilepsy. There were no significant differences in any hippocampal subfield volumes between patients who were rendered seizure free and those with persistent postoperative seizure symptoms. Ipsilateral but not contralateral HIA ratings were significantly correlated with gross hippocampal and subfield volumes.ConclusionsOur results suggest that ipsilateral hippocampal subfield volumes are not related to the chronicity/severity of TLE. We did not find any hippocampal subfield volume or HIA rating differences in patients with optimal and unfavorable outcomes. In patients with TLE and HS, sophisticated analysis of hippocampal architecture on MRI may have limited value for prediction of postoperative outcome.

Multiple sclerosis: High prevalence of the 'central vein' sign in white matter lesions on susceptibility-weighted images.

Purpose The aim of this study was to determine the occurrence and distribution of the 'central vein' sign in white matter lesions on susceptibility-weighted magnetic resonance images in patients with multiple sclerosis (MS) and cerebral small vessel disease (CSVD). Materials and methods T2-weighted and fluid-attenuated inversion recovery magnetic resonance images of 19 MS patients and 19 patients affected by CSVD were analysed for the presence and localisation of focal hyperintense white matter lesions. Lesions were subdivided into periventricular or non-periventricular (juxtacortical, subcortical, deep white matter and cerebellar) distributed. The number and localisation of lesions presenting with the central vein sign were recorded and compared between MS and CSVD lesions. Results A total of 313 MS patients and 75 CSVD lesions were identified on T2-weighted and fluid-attenuated inversion recovery magnetic resonance images. The central vein sign was found in 128 MS lesions (40.9%), and the majority of them (71/128, 55.5%) had a periventricular distribution. The central vein sign was found in 22 out of 75 (29.3%) CSVD lesions, and periventricular distribution was seen in six out of 22 (27.2%) CSVD lesions. The difference in the proportion of white matter hyperintense lesions that presented with the central vein sign on susceptibility-weighted images in patients with MS and CSVD was statistically different, and a significantly higher number of MS patients presented with lesions with the central vein sign compared to CSVD patients. Conclusion The presence of the central vein sign on susceptibility-weighted images for MS lesions improves the understanding of the periventricular distribution of MS lesions and could contribute as adjunctive diagnostic criteria for MS disease.

Iliopsoas Disorder in Athletes with Groin Pain: Prevalence in 638 Consecutive Patients Assessed with MRI and Clinical Results in 134 Patients with Signal Intensity Changes in the Iliopsoas.

Background:Although iliopsoas disorder is one of the most frequent causes of groin pain in athletes, little is known about its prevalence and clinical impact.Methods:We retrospectively reviewed the cases of 638 consecutive athletes who had groin pain. Each athlete was assessed with magnetic resonance imaging (MRI). First, we identified the prevalence of changes in signal intensity in the iliopsoas. Then we classified the changes in signal intensity in the iliopsoas, as visualized on short tau inversion recovery MRI, into 2 types: the muscle-strain type (characterized by a massive high-signal area in the muscle belly, with a clear border) and the peritendinitis type (characterized by a long and thin high-signal area extending proximally along the iliopsoas tendon from the lesser trochanter, without a clear border). Finally, we compared the time to return to play for the athletes who had these signal intensity changes.Results:Changes in signal intensity in the iliopsoas were detected in 134 (21.0%) of the 638 athletes. According to our MRI classification, 66 athletes had peritendinitis changes and 68 had muscle-strain changes. The time from the onset of groin pain to return to play was significantly shorter for the patients with muscle-strain changes on MRI than for those with peritendinitis changes (8.6 ± 8.3 versus 20.1 ± 13.9 weeks, respectively; p < 0.0001).Conclusions:Changes in MRI signal intensity in the iliopsoas were observed in 21.0% of 638 athletes who had groin pain. Distinguishing between muscle-strain changes and peritendinitis changes could help to determine the time to return to play.

Correlations Between the Degree of Endolymphatic Hydrops and Symptoms and Audiological Test Results in Patients With Menière's Disease: A Reevaluation.

This study was performed to reevaluate the diagnostic significance of clinically well-accepted audiological tests in indicating endolymphatic hydrops (EH) in Menière's disease (MD). Retrospective case review. Hospital. Fifty patients (52 affected ears) diagnosed with MD were enrolled. Diagnostic. To analyze the correlations between endolymphatic hydrops and results of audiological test including the pure-tone audiometry threshold, suprathreshold function tests, electrocochleogram, and glycerol test. Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging demonstrated EH in either the vestibule or cochlea to various degrees in all of the MD patients, 24 hours after intratympanic gadolinium chelate injection. Both vestibular and cochlear EH were significantly correlated with PTA threshold. However, EH was not associated with alternate binaural loudness balance or the tone decay test, although a correlation was observed with the short-increment sensitivity index. There was also a correlation between vestibular EH, but not cochlear EH, and the negative summating potential/action potential (-SP/AP) ratio. Neither vestibular EH nor cochlear EH was correlated with the glycerol test results. In addition, the frequency of vertigo attacks, the existence of tinnitus, and aural fullness did not correlate with EH. Disrupted ionic homeostasis in the inner ear, but not the EH, may contribute to changes in the -SP/AP ratio. The relevance of glycerol test in identifying EH through detection of hearing changes needs further investigation in the future.

Chronic recurrent multifocal osteomyelitis: a case report

BackgroundChronic recurrent multifocal osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis, is a rare, noninfectious inflammatory disorder that causes multifocal bone lesions with swelling and pain. Lytic and sclerotic bone lesions could be found on X-ray. Short tau inversion recovery magnetic resonance imaging (STIR MRI) shows bone marrow oedema, bone expansion, lytic areas and periosteal reaction. CRMO is characterized by periodic exacerbations and remissions of unclear/unknown pathogenesis.Case presentationA 10 years old girl, suffering from pain in her right shoulder since the age of 9 years presented to our Department. Thanks to clinical data, laboratoristic and radiological findings and bone biopsy CRMO was diagnosed. So patient started anti-inflammatory treatment and her conditions improved.ConclusionsIn a child with bone pain should be considered also rare condition as CRMO to perform a correct diagnosis and start an adequate treatment avoiding complications such as bone damage. This condition should be suspected in a child with recurrent bone pain, modest increase of inflammatory indices, lytic or sclerotic bone lesion on X Ray. Typical CRMO localizations are metaphyses of long bones, pelvis, clavicle, vertebral column, sternum, ribs, jaw, but any bone can be involved. The most common CRMO differential diagnosis is represented by infections, malignant bone tumors, Langerhans Cells Histiocytosis (LCH).

Significance of novel subcortical low intensity score on transient neurological events after revascularization surgery for moyamoya disease

ObjectivesTransient neurological events (TNEs) are frequently observed after revascularization surgery for moyamoya disease (MMD). Recently, two signs on fluid-attenuated inversion recovery magnetic resonance images, a cortical hyperintensity belt (CHB) sign possibly reflecting vasogenic edema and a transient subcortical low intensity (SCLI) sign possibly reflecting cytotoxic edema, were reported associated with TNEs. The purpose of this study was to create a SCLI score and to investigate the significance of the score in TNEs. Patients and methodsThe authors retrospectively analyzed 18 cerebral hemispheres in 16 consecutive patients with revascularization surgery for MMD. The SCLI sign was defined as a transient SCLI in surgically treated hemispheres, and blindly graded as the SCLI score (0–4) based on the extent. The relationships among SCLI, CHB signs and TNEs were evaluated. ResultsPostoperative TNEs, SCLI and CHB signs were detected in 8 (44.4%), 9 (50.0%) and 12 (66.7%) hemispheres, respectively. Patients with SCLI and CHB signs had a significantly higher TNE occurrence rate than those without these signs (p = 0.015, and p = 0.013, respectively). Patients with TNEs showed significantly higher SCLI scores than those without TNEs (p = 0.009), while the difference of CHB scores did not reach significance between patients with and without TNEs. For the occurrence of postoperative TNEs, SCLI score with a cut-off value of 1.0 resulted in a specificity of 80.0% and a sensitivity of 87.5%. ConclusionThe novel SCLI score may be useful for diagnosing TNEs after revascularization surgery for MMD, although both vasogenic and cytotoxic edema may be involved in postoperative TNEs.

Abrogation of fluid suppression in intracranial postcontrast fluid‐attenuated inversion recovery magnetic resonance imaging: A clinical and phantom study

Postcontrast, fluid-attenuated inversion recovery (FLAIR) sequences are reported to be of variable value in veterinary and human neuroimaging. The source of hyperintensity in postcontrast-T2 FLAIR images is inconsistently reported and has implications for the significance of imaging findings. We hypothesized that the main source of increased signal intensity in postcontrast-T2 FLAIR images would be due to gadolinium leakage into adjacent fluid, and that the resulting gadolinium-induced T1 shortening causes reappearance of fluid hyperintensity, previously nulled on precontrast FLAIR images. A retrospective, descriptive study was carried out comparing T2 weighted, pre- and postcontrast T1 weighted and pre- and postcontrast weighted T2 FLAIR images in a variety of intracranial diseases in dogs and cats. A prospective, experimental, phantom, in vitro study was also done to compare the relative effects of gadolinium concentration on T2 weighted, T1 weighted, and FLAIR images. A majority of hyperintensities on postcontrast-T2 FLAIR images that were not present on precontrast FLAIR images were also present on precontrast T2 weighted images, and were consistent with normal or pathological fluid filled structures. Phantom imaging demonstrated increased sensitivity of FLAIR sequences to low concentrations of gadolinium compared to T1 weighted sequences. Apparent contrast enhancement on postcontrast-T2 FLAIR images often reflects leakage of gadolinium across normal or pathology specific barriers into fluid-filled structures, and hyperintensity may therefore represent normal fluid structures as well as pathological tissues. Findings indicated that postcontrast-T2 FLAIR images may provide insight into integrity of biological structures such as the ependymal and subarachnoid barriers that may be relevant to progression of disease.

Utilizing 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) to define suspected nonenhancing tumor for radiation therapy planning of glioblastoma

AimThe authors sought to evaluate the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and the presence of suspected nonenhancing tumors compared with standard magnetic resonance imaging (MRI). Methods and materialsPatients with GBM and contrast-enhanced MRI scans showing regions suspicious of nonenhancing tumor underwent postoperative FET-PET before commencing radiation therapy. Two clinical target volumes (CTVs) were created using pre- and postoperative MRI: MRI fluid-attenuated inversion recovery (FLAIR) sequences (CTVFLAIR) and MRI contrast sequences with an expansion on the surgical cavity (CTVSx). FET-PET was used to create biological tumor volumes (BTVs) by encompassing FET-avid regions, forming BTVFLAIR and BTVSx. Volumetric analyses were conducted between CTVs and respective BTVs using Wilcoxon signed-rank tests. The volume increase with addition of FET was analyzed with respect to BTVFLAIR and BTVSx. Presence of focal gadolinium contrast enhancement within previously nonenhancing tumor or within the FET-avid region was noted on MRI scans at 1 and 3 months after radiation therapy. ResultsTwenty-six patients were identified retrospectively from our database, of whom 24 had demonstrable FET uptake. The median CTVFLAIR, CTVSx, BTVFLAIR, and BTVSx were 57.1 mL (range, 1.1-217.4), 83.6 mL (range, 27.2-275.8), 62.8 mL (range, 1.1-307.3), and 94.7 mL (range, 27.2-285.5), respectively. When FET-PET was used, there was a mean increase in volume of 26.8% from CTVFLAIR to BTVFLAIR and 20.6% from CTVSx to BTVSx. A statistically significant difference was noted on Wilcoxon signed-rank test when assessing volumetric change between CTVFLAIR and BTVFLAIR (P < .0001) and CTVSx and BTVSx (P < .0001). Six of 24 patients (25%) with FET avidity before radiation therapy showed focal gadolinium enhancement within the radiation therapy portal. ConclusionsFET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component. This may result in improved radiation therapy target delineation and reduce the risk of potential geographical miss. SummaryWe investigated the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and a suspected nonenhancing tumor compared with standard magnetic resonance imaging. We performed volumetric analyses between clinical target volumes and respective biological target volumes using Wilcoxon signed-rank tests. FET-PET may help improve delineation of GBM in cases with a suspected nonenhancing component and reduce the risk of potential geographical miss.

Clinical value of 4-hour delayed gadolinium-Enhanced 3D FLAIR MR Images in Acute Vestibular Neuritis.

To investigate the clinical significance of 4-hour delayed-enhanced 3.0 Tesla three-dimensional (3D) fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging in acute vestibular neuritis. A prospective observational study. Twenty-nine vestibular neuritis patients were enrolled between January 2017 and June 2017. Vestibular function tests, comprising the caloric and video head impulse tests and vestibular-evoked myogenic potential measurements, were performed. Precontrast, 10-minute, and 4-hour delayed-enhanced 3D-FLAIR MR images using double-dose IV gadolinium were obtained. After laterality and extent of inner ear enhancement were defined, the patients were divided into groups based on the patterns of enhancement, and clinical parameters were analyzed according to the groups. Twenty patients (20 of 29, 69.0%) had obviously asymmetric enhancement of the affected inner ear structures on 4-hour delayed images, whereas only three patients (10.3%) had marked enhancement on 10-minute delayed images. The duration of spontaneous nystagmus (DurSN) was significantly longer in the patients with enhancement, especially with enhancement of the whole inner ear, including the vestibule and semicircular canals (P < 0.033). Spontaneous nystagmus resolved within 12 days in patients without laterality of enhancement, and within 16 days in ipsilesional enhancement confined to the inner auditory canal and fundus. Other results of vestibular function tests did not reveal any significant associations with MR enhancement. Contrast enhancement of the vestibular nerve and inner ear structures can be identified on 4-hour delayed-enhanced 3T 3D-FLAIR MR images in acute vestibular neuritis. The extent of inner ear enhancement may be associated with the DurSN. 4. Laryngoscope, 1946-1951, 2018.

Ventricular and Periventricular Anomalies in the Aging and Cognitively Impaired Brain.

Ventriculomegaly (expansion of the brain’s fluid-filled ventricles), a condition commonly found in the aging brain, results in areas of gliosis where the ependymal cells are replaced with dense astrocytic patches. Loss of ependymal cells would compromise trans-ependymal bulk flow mechanisms required for clearance of proteins and metabolites from the brain parenchyma. However, little is known about the interplay between age-related ventricle expansion, the decline in ependymal integrity, altered periventricular fluid homeostasis, abnormal protein accumulation and cognitive impairment. In collaboration with the Baltimore Longitudinal Study of Aging (BLSA) and Alzheimer’s Disease Neuroimaging Initiative (ADNI), we analyzed longitudinal structural magnetic resonance imaging (MRI) and subject-matched fluid-attenuated inversion recovery (FLAIR) MRI and periventricular biospecimens to map spatiotemporally the progression of ventricle expansion and associated periventricular edema and loss of transependymal exchange functions in healthy aging individuals and those with varying degrees of cognitive impairment. We found that the trajectory of ventricle expansion and periventricular edema progression correlated with degree of cognitive impairment in both speed and severity, and confirmed that areas of expansion showed ventricle surface gliosis accompanied by edema and periventricular accumulation of protein aggregates, suggesting impaired clearance mechanisms in these regions. These findings reveal pathophysiological outcomes associated with normal brain aging and cognitive impairment, and indicate that a multifactorial analysis is best suited to predict and monitor cognitive decline.

Contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging was useful in detecting inflammation of the meninges in neuropsychiatric systemic lupus erythematosus: a case report

A 49-year-old woman was admitted to our hospital with recurrent episodes of paresthesia attacks evolving in 5 to 15 minutes from the left hand to the left leg through the left trunk. Neurological examination revealed cortical sensory disturbance in her left hand. Although contrast-enhanced T1-weighted MRI findings were unremarkable, contrast-enhanced fluid-attenuated inversion recovery (FLAIR) MRI revealed abnormal leptomeningeal enhancement over the sulcus of the parietal lobe, including the sulcus around the postcentral gyrus. Because we assumed the cause of the recurrent sensory attack to be meningeal inflammation around the primary somatosensory cortex, we treated this patient by increasing the dose of prednisolone. The increase in prednisolone dose completely resolved the symptom, as well as the abnormal leptomeningeal enhancement on contrast-enhanced FLAIR MRI. In patients with suspected meningeal inflammation, contrast-enhanced FLAIR MRI, which is reported to be more sensitive than contrast-enhanced T1-weighted MRI in detecting subtle abnormal leptomeningeal enhancement, should be the modality of choice.

Innovation in the imaging perianal fistula: a step towards personalised medicine.

Background:Perianal fistula is a topic both hard to understand and to teach. The key to understanding the treatment options and the likely success is deciphering the exact morphology of the tract(s) and the amount of sphincter involved. Our aim was to explore alternative platforms better to understand complex perianal fistulas through three-dimensional (3D) imaging and reconstruction.Methods:Digital imaging and communications in medicine images of spectral attenuated inversion recovery magnetic resonance imaging (MRI) sequences were imported onto validated open-source segmentation software. A specialist consultant gastrointestinal radiologist performed segmentation of the fistula, internal and external sphincter. Segmented files were exported as stereolithography files. Cura (Ultimaker Cura 3.0.4) was used to prepare the files for printing on an Ultimaker 3 Extended 3D printer. Animations were created in collaboration with Touch Surgery™.Results:Three examples of 3D printed models demonstrating complex perianal fistula were created. The anatomical components are displayed in different colours: red: fistula tract; green: external anal sphincter and levator plate; blue: internal anal sphincter and rectum. One of the models was created to be split in half, to display the internal opening and allow complexity in the intersphincteric space to better evaluated. An animation of MRI fistulography of a trans-sphincteric fistula tract with a cephalad extension in the intersphincteric space was also created.Conclusion:MRI is the reference standard for assessment of perianal fistula, defining anatomy and guiding surgery. However, communication of findings between radiologist and surgeon remains challenging. Feasibility of 3D reconstructions of complex perianal fistula is realized, with the potential to improve surgical planning, communication with patients, and augment training.

Regional tract-specific white matter hyperintensities are associated with patterns of aging-related brain atrophy via vascular risk factors, but also independently

IntroductionWe sought to investigate associations of regional white matter hyperintensities (WMHs) within white matter (WM) tracts with cardiovascular risk and brain aging-related atrophy throughout adulthood in the general population, leveraging state of the art pattern analysis methods. MethodsWe analyzed a large sample (n = 2367) from the Study of Health in Pomerania, Germany (range 20–90 years). WMHs were automatically segmented on T1-weighted and fluid-attenuated inversion recovery magnetic resonance images, and WMH volumes were calculated in WM regions defined using the John Hopkins University WM tractography atlas. Regions with the highest average WMH volume were selected. We calculated a subject-specific index, Spatial Pattern of Alteration for Recognition of Brain Aging, to measure age-related atrophy patterns. The Framingham cardiovascular disease risk score summarized the individual cardiovascular risk profile. We used structural equation models, independently for each region, using Spatial Pattern of Alteration for Recognition of Brain Aging as a dependent variable, age as an independent variable, and cardiovascular disease risk score and regional WMH volumes as mediators. ResultsSelected 12 WM regions included 75% of the total WMH burden in average. Structural equation models showed that the age effect on Spatial Pattern of Alteration for Recognition of Brain Aging was mediated by WMHs to a different extent in the superior frontal WM, anterior corona radiata, inferior frontal WM, superior corona radiata, superior longitudinal fasciculus, middle temporal WM, posterior corona radiata, superior parietal WM, splenium of corpus callosum, posterior thalamic radiation, and middle occipital WM (variance explained between 2.8% and 10.3%, P < .0001 Bonferroni corrected), but not in precentral WM. ConclusionsOur results indicate that WMHs, in most WM tracts, might accelerate the brain aging process throughout adulthood in the general population as a result of vascular risk factors, but also independent of them. Preventive strategies against WMHs (such as controlling vascular risk factors or microglia depletion) could delay brain aging.

Diagnosis of Meningitis Caused by Pathogenic Microorganisms Using Magnetic Resonance Imaging: A Systematic Review

Introduction:Bacterial meningitis is an acute infectious inflammation of the protective membranes covering the brain. Its early diagnosis is vital because of its high morbidity and mortality. It is mostly diagnosed by a gold standard diagnostic tool i.e. Cerebrospinal Fluid (CSF) analysis. However, it is sometimes difficult and or impossible to do this procedure and an alternative diagnostic tool is needed. Contrast enhanced magnetic resonance imaging can detect the pus or other changes in subarachnoid space. But our optimal aim is to use an imaging method without using contrast to be useable and available in more specific condition.Methods:This study aimed to survey the role of non-contrast Magnetic Resonance Imaging (MRI) in the diagnosis of the bacterial meningitis. MEDLINE/PubMed Central, Web of Science and Scopus were searched without time period and language limitation until March 2017. We found 6410 papers in our initial search. After assessing the content of the papers based on Cochrane library guidelines and inclusion/exclusion criteria, 6 relevant studies were included in the systematic review. All of included studies were observational studies.Results:MRI studies demonstrated that Fluid Attenuation Inversion Recovery (FLAIR) and Diffusion-Weighted Image (DWI) MR imaging among all MRI modalities can detect some abnormalities compatible with bacterial meningitis. FLAIR and DWI-MR imaging are potentially useful to diagnose bacterial meningitis and can be used in emergent condition in which bacterial meningitis is highly suspicious and the other diagnostic tools are not available or feasible.

Carotid Intima-Media Thickness Is Associated With White Matter Hyperintensities: The Northern Manhattan Study.

Brain white matter hyperintensities (WMH) have been associated with increased risk of stroke, cognitive decline, and dementia. WMH can be a manifestation of small vessel disease, although the total microvascular contribution to multifactorial WMH pathophysiology remains unknown. We hypothesized a possible relationship between carotid intima-media thickness (cIMT), an ultrasound imaging marker of subclinical vascular disease, and brain WMH in a multiethnic, elderly stroke-free community-based cohort. We evaluated the relationship between cIMT and WMH in the population-based Northern Manhattan Study, among individuals free of stroke. We used linear regression to examine the association of continuous measures of cIMT with quantitatively derived WMH volume, as a proportion of cranial volume, measured from fluid-attenuaded inversion recovery magnetic resonance imaging while adjusting for sociodemographics, lifestyle, and vascular risk factors. In a cohort of 1229 participants (mean age, 71±9 years; 60% women, 15% White; 18% Black; 65% Hispanics), the mean cIMT was 0.71±0.08 mm and the median log-transformed WMH volume was 0.36 (interquartile range, 0.21-0.76). In a multivariable model, larger cIMT was significantly associated with greater WMH volume (β=0.046 per SD cIMT; P=0.04). Age and race/ethnicity were significant modifiers (P for age, 0.02; and P for race/ethnicity, 0.04). cIMT was associated with WMH volume in participants 70 years or older (β=0.088 per SD cIMT; P=0.01) and among Hispanics (β=0.084 per SD cIMT; P=0.003). Larger cIMT was associated with greater burden of cerebral WM lesions independently of demographics and traditional vascular risk factors, particularly among elderly and Hispanic participants, who are at high risk for stroke and cognitive decline.

Low cortical iron and high entorhinal cortex volume promote cognitive functioning in the oldest-old

The aging brain is characterized by an increased presence of neurodegenerative and vascular pathologies. However, there is substantial variation regarding the relationship between an individual's pathological burden and resulting cognitive impairment. To identify correlates of preserved cognitive functioning at highest age, the relationship between β-amyloid plaque load, presence of small vessel cerebrovascular disease (SVCD), iron-burden, and brain atrophy was investigated. Eighty cognitively unimpaired participants (44 oldest-old, aged 85–96 years; 36 younger-old, aged 55–80 years) were scanned by integrated positron emission tomography–magnetic resonance imaging for assessing beta regional amyloid plaque load (18F-flutemetamol), white matter hyperintensities as an indicator of SVCD (fluid-attenuated inversion recovery–magnetic resonance imaging), and iron load (quantitative susceptibility mapping). For the oldest-old group, lower cortical volume, increased β-amyloid plaque load, prevalence of SVCD, and lower cognitive performance in the normal range were found. However, compared to normal-old, cortical iron burden was lower in the oldest-old. Moreover, only in the oldest-old, entorhinal cortex volume positively correlated with β-amyloid plaque load. Our data thus indicate that the co-occurrence of aging-associated neuropathologies with reduced quantitative susceptibility mapping measures of cortical iron load constitutes a lower vulnerability to cognitive loss.

Hyperintensity of Cerebrospinal Fluid on T2-Weighted Fluid-Attenuated Inversion Recovery Magnetic Resonance Imaging Caused by High Inspired Oxygen Fraction.

In veterinary medicine, patients undergo magnetic resonance imaging (MRI) under general anesthesia to enable acquisition of artifact-free images. The fraction of inspired oxygen (FiO2) ranges between 30 and 95%. In humans, a high FiO2 is associated with incomplete signal suppression of peripheral cerebrospinal fluid (CSF) spaces on T2-weighted fluid-attenuated inversion recovery (T2w-FLAIR) sequences. The influence of FiO2 on T2w-FLAIR images remains unreported in small animals. The aim of this prospective study was to investigate whether a high FiO2 is associated with hyperintensity in peripheral CSF spaces on T2w-FLAIR images in dogs and cats. Client-owned patients undergoing brain MRI were prospectively enrolled. Animals with brain parenchymal abnormalities and/or meningeal contrast enhancement on MRI images and/or abnormal CSF analysis were excluded. Consequently, twelve patients were enrolled. Anesthesia was maintained by isoflurane 0.5–1 minimal alveolar concentration in 30% oxygen. After acquisition of transverse and dorsal T2w-FLAIR images, the FiO2 was increased to 95%. The T2w-FLAIR sequences were then repeated after 40 min. Arterial blood gas analysis was performed in six patients at the same time as T2w-FLAIR sequence acquisition. Plot profiles of the signal intensity (SI) from CSF spaces of three cerebral sulci and adjacent gray and white matter were generated. SI ratios of CSF space and white matter were compared between the T2w-FLAIR images with 30 and 95% FiO2. An observer blinded to the FiO2, subjectively evaluated the SI of peripheral CSF spaces on T2w-FLAIR images as high or low. There was significant difference in the partial pressure of oxygen between the two arterial samples (P < 0.001). The SI ratios obtained from the T2w-FLAIR images with 95% FiO2 were significantly higher compared with those obtained from the T2w-FLAIR images with 30% FiO2 (P < 0.05). The peripheral CSF spaces were subjectively considered hyperintense in 11 of 12 cases on T2w-FLAIR images with 95% FiO2 (P < 0.005). A clear difference in SI, dependent on the FiO2 was seen in the peripheral CSF spaces on T2w-FLAIR images. In conclusion, the influence of FiO2 must be considered when differentiating pathological and normal CSF spaces on T2w-FLAIR images in dogs and cats.

A large margin algorithm for automated segmentation of white matter hyperintensity

Precise detection and quantification of white matter hyperintensity (WMH) is of great interest in studies of neurological and vascular disorders. In this work, we propose a novel method for automatic WMH segmentation with both supervised and semi-supervised large margin algorithms provided by the framework. The proposed algorithms optimize a kernel based max-margin objective function which aims to maximize the margin between inliers and outliers. We show that the semi-supervised learning problem can be formulated to learn a classifier and label assignment simultaneously, which can be solved efficiently by an iterative algorithm. The model is learned first via the supervised approach and then fine-tuned on a target image by using the semi-supervised algorithm. We evaluate our method on 88 brain fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) images from subjects with vascular disease. Quantitative evaluation of the proposed approach shows that it outperforms other well known methods for WMH segmentation.