Fluid-attenuated Inversion Recovery Magnetic Resonance Imaging Research Articles

Predicting Outcome after Pediatric Traumatic Brain Injury by Early Magnetic Resonance Imaging Lesion Location and Volume.

Brain lesions after traumatic brain injury (TBI) are heterogeneous, rendering outcome prognostication difficult. The aim of this study is to investigate whether early magnetic resonance imaging (MRI) of lesion location and lesion volume within discrete brain anatomical zones can accurately predict long-term neurological outcome in children post-TBI. Fluid-attenuated inversion recovery (FLAIR) MRI hyperintense lesions in 63 children obtained 6.2±5.6 days postinjury were correlated with the Glasgow Outcome Scale Extended-Pediatrics (GOS-E Peds) score at 13.5±8.6 months. FLAIR lesion volume was expressed as hyperintensity lesion volume index (HLVI)=(hyperintensity lesion volume / whole brain volume)×100 measured within three brain zones: zone A (cortical structures); zone B (basal ganglia, corpus callosum, internal capsule, and thalamus); and zone C (brainstem). HLVI-total and HLVI-zone C predicted good and poor outcome groups (p<0.05). GOS-E Peds correlated with HLVI-total (r=0.39; p=0.002) and HLVI in all three zones: zone A (r=0.31; p<0.02); zone B (r=0.35; p=0.004); and zone C (r=0.37; p=0.003). In adolescents ages 13-17 years, HLVI-total correlated best with outcome (r=0.5; p=0.007), whereas in younger children under the age of 13, HLVI-zone B correlated best (r=0.52; p=0.001). Compared to patients with lesions in zone A alone or in zones A and B, patients with lesions in all three zones had a significantly higher odds ratio (4.38; 95% confidence interval, 1.19-16.0) for developing an unfavorable outcome.

Comparison of noninvasive evaluation of endolymphatic space in healthy volunteers in different age groups using magnetic resonance imaging

Conclusions: Noninvasive standard evaluation of normal endolymphatic space and endolymphatic hydrops using magnetic resonance imaging (MRI) in various age groups is reported for the first time. Objective: To compare the standard evaluation of endolymphatic space in healthy volunteers in the cochlea and the vestibule among different age groups by applying noninvasive intratympanic gadolinium (Gd) perfusion through the eustachian tube and three-dimensional fluid-attenuated inversion recovery MRI (3D-FLAIR MRI). Methods: This was a prospective study. 3D-FLAIR MRI was performed with a 3 T unit 24 h after intratympanic administration of Gd through the eustachian tube in 60 healthy volunteers aged 20–55 years. Pure-tone test and tympanometry were performed 24 h before and 1 week after Gd administration. Results: There was no significant difference in the ratios of the area of the endolymphatic space to that of the fluid space in the cochlea and the vestibule between males and females, or among 20–30-, 31–44-, and 45–55-year-old healthy volunteers. In 20–55-year-old healthy volunteers, the normal value of the endolymphatic space in the cochlea ranged between 7% and 27%, and that in the vestibule was between 17% and 39%. No significant changes in pure-tone test or tympanometry were noted.

Unidentified Bright Objects on Brain Magnetic Resonance Imaging Affect Vestibular Neuritis.

ObjectivesThe aim of this study was to investigate the differences in clinical manifestations of in two groups of vestibular neuritis (VN) patients with or without unidentified bright objects (UBOs).MethodsA prospective, observational study with 46 patients diagnosed with VN between May 2013 and November 2013 was executed. A caloric test, a cervical vestibular-evoked myogenic potentials (cVEMPs) test, brain magnetic resonance imaging (MRI), spontaneous nystagmus test, head impulse test, and head-shaking nystagmus test were performed.ResultsOf the patients, 56.5% (n=26) were classified as UBO-positive by MRI. These showed lower caloric weakness and more prominent cVEMP asymmetry compared with the UBO-negative group (P<0.05). Total VN (TVN) was the most common in the UBO-positive group (45.0%), followed by superior VN (SVN, 30.0%), and inferior VN (IVN, 25.0%). However, in the UBO-negative group, SVN (75.0%) was the most common, followed by TVN and IVN (P<0.05). The recovery rate was not influenced by UBOs (P>0.05).ConclusionUBOs on T2-weighted or fluid attenuated inversion recovery MRI may affect the patterns of the vestibular nerve in patients with VN.

Automated Feature Extraction in Brain Tumor by Magnetic Resonance Imaging Using Gaussian Mixture Models.

This paper presents a novel method for Glioblastoma (GBM) feature extraction based on Gaussian mixture model (GMM) features using MRI. We addressed the task of the new features to identify GBM using T1 and T2 weighted images (T1-WI, T2-WI) and Fluid-Attenuated Inversion Recovery (FLAIR) MR images. A pathologic area was detected using multithresholding segmentation with morphological operations of MR images. Multiclassifier techniques were considered to evaluate the performance of the feature based scheme in terms of its capability to discriminate GBM and normal tissue. GMM features demonstrated the best performance by the comparative study using principal component analysis (PCA) and wavelet based features. For the T1-WI, the accuracy performance was 97.05% (AUC = 92.73%) with 0.00% missed detection and 2.95% false alarm. In the T2-WI, the same accuracy (97.05%, AUC = 91.70%) value was achieved with 2.95% missed detection and 0.00% false alarm. In FLAIR mode the accuracy decreased to 94.11% (AUC = 95.85%) with 0.00% missed detection and 5.89% false alarm. These experimental results are promising to enhance the characteristics of heterogeneity and hence early treatment of GBM.

Visualization of brain white matter tracts using heavily t2-weighted three-dimensional fluid-attenuated inversion-recovery magnetic resonance imaging.

The purpose of this study was to elucidate which white matter (WM)-tracts are visualized on heavily T2-weighted three-dimensional fluid-attenuated inversion-recovery (hT2w-3D-FLAIR) images. Records of seven patients who underwent hT2w-3D-FLAIR and diffusion tensor imaging (DTI) of the head at 3 Tesla were analyzed. Two neuroradiologists determined WM-tracts visualized on hT2w-3D-FLAIR and identified anatomical points through which they ran. A third neuroradiologist determined the WM-tracts running through those points on DTI. Correspondence between hT2w-3D-FLAIR and DTI WM-tracts was used to confirm technique validity. As a result, the corticospinal tract (CST), medial lemniscus (ML), and superior cerebellar peduncle (SCP) were visualized as high intensity on hT2w-3D-FLAIR and ran through the following points: CST, 20 mm lateral from the lateral margin of the third ventricle at the thalamic level; ML, 6 mm anterior to the anterior margin of the fourth ventricle at the trigeminal nerve level; and SCP, just lateral to the fourth ventricle at the trigeminal nerve level. The third neuroradiologist determined that the WM-tracts ran through those points on DTI in all patients. Consequently, WM-tracts determined on hT2w-3D-FLAIR and DTI completely corresponded. In conclusion, the CST, ML, and SCP were visualized as high intensity on hT2w-3D-FLAIR. This technique is a potentially supplemental DTI neurographic modality.

Contrast-Enhanced FLAIR (Fluid-Attenuated Inversion Recovery) for Evaluating Mild Traumatic Brain Injury

PurposeTo evaluate whether adding a contrast-enhanced fluid-attenuated inversion recovery (FLAIR) sequence to routine magnetic resonance imaging (MRI) can detect additional abnormalities in the brains of symptomatic patients with mild traumatic brain injury.Materials and MethodsFifty-four patients with persistent symptoms following mild closed head injury were included in our retrospective study (M∶F = 32∶22, mean age: 59.8±16.4, age range: 26–84 years). All MRI examinations were obtained within 14 days after head trauma (mean: 3.2±4.1 days, range: 0.2–14 days). Two neuroradiologists recorded (1) the presence of traumatic brain lesions on MR images with and without contrast-enhanced FLAIR images and (2) the pattern and location of meningeal enhancement depicted on contrast-enhanced FLAIR images. The number of additional traumatic brain lesions diagnosed with contrast-enhanced FLAIR was recorded. Correlations between meningeal enhancement and clinical findings were also evaluated.ResultsTraumatic brain lesions were detected on routine image sequences in 25 patients. Three additional cases of brain abnormality were detected with the contrast-enhanced FLAIR images. Meningeal enhancement was identified on contrast-enhanced FLAIR images in 9 cases while the other routine image sequences showed no findings of traumatic brain injury. Overall, the additional contrast-enhanced FLAIR images revealed more extensive abnormalities than routine imaging in 37 cases (p<0.001). In multivariate logistic regression analysis, subdural hematoma and posttraumatic loss of consciousness showed a significant association with meningeal enhancement on contrast-enhanced FLAIR images, with odds ratios 13.068 (95% confidence interval 2.037 to 83.852), and 15.487 (95% confidence interval 2.545 to 94.228), respectively.ConclusionMeningeal enhancement on contrast-enhanced FLAIR images can help detect traumatic brain lesions as well as additional abnormalities not identified on routine unenhanced MRI. Therefore contrast-enhanced FLAIR MR imaging is recommended when a contrast MR study is indicated in a patient with a symptomatic prior closed mild head injury.

Detection of acute small amount of subarachnoid hemorrhage: Comparison between fluid-attenuated inversion recovery MR imaging and CT

PurposeTo evaluate the possibility of detecting small amount of acute subarachnoid hemorrhage (ASH) diluted by CSF not revealed by CT but identified on fluid-attenuated inversion recovery (FLAIR) MRI. Patients and methods50 patients with acute neurological symptoms were referred from the neurosurgery department to the radiodiagnosis department for computed tomography CT and magnetic resonance imaging MRI examination. ResultsLumbar puncture proved 41 positive cases, MRI (FLAIR) interpreted 43 positive cases (40 true positive and 3 false positive) and 7 negative cases (6 true negative and one false negative) while CT interpreted 39 positive cases (37 true positive and 2 false positive) and 11 negative cases (7 true negative and 4 false negative). ConclusionFLAIR MRI was more sensitive and more accurate in the diagnosis of acute SAH than CT scan, having a much higher negative predictive value to exclude acute SAH, however its positive predictive value was slightly lower than CT, but there was no statistically significant difference statistically between the two in diagnosis of SAH.

In Vivo Assessment of Brain White Matter Inflammation in Multiple Sclerosis with (18)F-PBR111 PET.

PET radioligand binding to the 18-kD translocator protein (TSPO) in the brains of patients with multiple sclerosis (MS) primarily reflects activated microglia and macrophages. We previously developed genetic stratification for accurate quantitative estimation of TSPO using second-generation PET radioligands. In this study, we used (18)F-PBR111 PET and MR imaging to measure relative binding in the lesional, perilesional, and surrounding normal-appearing white matter of MS patients, as an index of the innate immune response. (18)F-PBR111 binding was quantified in 11 MS patients and 11 age-matched healthy volunteers, stratified according to the rs6971 TSPO gene polymorphism. Fluid-attenuated inversion recovery and magnetization transfer ratio (MTR) MR imaging were used to segment the white matter in MS patients as lesions, perilesional volumes, nonlesional white matter with reduced MTR, and nonlesional white matter with normal MTR. (18)F-PBR111 binding was higher in the white matter lesions and perilesional volumes of MS patients than in white matter of healthy controls (P < 0.05). Although there was substantial heterogeneity in binding between different lesions, a within-subject analysis showed higher (18)F-PBR111 binding in MS lesions (P < 0.05) and in perilesional (P < 0.05) and nonlesional white matter with reduced MTR (P < 0.005) than in nonlesional white matter with a normal MTR. A positive correlation was observed between the mean (18)F-PBR111 volume of distribution increase in lesions relative to nonlesional white matter with a normal MTR and the MS severity score (Spearman ρ = 0.62, P < 0.05). This study demonstrates that quantitative TSPO PET with a second-generation radioligand can be used to characterize innate immune responses in MS in vivo and provides further evidence supporting an association between the white matter TSPO PET signal in lesions and disease severity. Our approach is practical for extension to studies of the role of the innate immune response in MS for differentiation of antiinflammatory effects of new medicines and their longer term impact on clinical outcome.

Audiovestibular Characteristics of Small Cochleovestibular Schwannomas in Neurofibromatosis Type 2

Describe the relationship between cochleovestibular schwannoma (CVS) volume, audiovestibular characteristics, and magnetic resonance imaging (MRI) findings in patients with neurofibromatosis type 2 (NF2). Subgroup analysis of NF2 prospective natural history study from 2008 to 2011. Quaternary medical research institute. NF2 patients with small treatment-naive CVSs (volume <1000 mm(3)) by ear; N = 49 ears (32 patients). Cross-sectional analysis of the following parameters was performed: tumor size, auditory brainstem response (ABR), 4-frequency pure-tone average (4f-PTA; 0.5, 1, 2, and 4KHz), cervical vestibular evoked myogenic potential (cVEMP), caloric testing, 240° velocity step test (VST), and MRI findings. For all physiologic measures but the 4f-PTA, larger tumors correlated with abnormal responses (P < .05). For abnormal ABR, mean tumor volume was 405 vs 151 mm(3) (P = .0007) for normal ABR. Similarly, larger tumors correlated with weak caloric responses (mean 521 vs 165 mm(3); P = .0007) and weak cVEMP (mean 357 vs 192 mm(3); P = .0262). Tumor volume was not significantly correlated with 4f-PTA. Elevated intralabyrinthine protein on MRI fluid-attenuated inversion recovery sequences was correlated with larger tumor volume (mean 333 vs 55 mm(3); P = .001) and abnormal ABR and 4f-PTA (P < .05) but did not correlate with cVEMP, VST, or caloric responses. In our cohort, ABR, caloric response, cVEMP, and elevated intralabyrinthine protein correlated with tumor volume, but 4f-PTA did not. Abnormal ABR and 4f-PTA correlated with elevated intralabyrinthine protein. These findings may provide insight on the effect of small CVS on the inner ear and cochleovestibular nerves, which may aid in their optimal management.

Pediatric MRI of the Brain: A Primer

1. Kamakshya P. Patra, MD* 2. Jeffrey D. Lancaster, MD* 3. Jeffery Hogg, MD† 4. Jeffrey S. Carpenter, MD† 1. *Department of Pediatrics, Section of Hospital Pediatrics, West Virginia University Children’s Hospital, Morgantown, WV. 2. †Department of Neuroradiology, West Virginia University Health Sciences Center, Morgantown, WV. * Abbreviations: ADHD: : attention-deficit/hyperactivity disorder CSF: : cerebrospinal fluid CT: : computed tomography DWI: : diffusion-weighted magnetic resonance imaging FLAIR: : fluid-attenuated inversion recovery fMRI: : functional magnetic resonance imaging MRI: : magnetic resonance imaging MRV: : magnetic resonance venography NAA: : N -acetylaspartate SDH: : subdural hematoma Because of recent advances in magnetic resonance imaging (MRI) techniques, pediatricians should be aware of the different modalities and their unique advantages and appropriateness in different clinical situations. After completing this article, readers should be able to: 1. Understand the pros and cons of MRI and computed tomography of the brain. 2. Know the basic principles of MRI and its different image modalities. 3. Be aware of the appropriateness of different modalities in specific clinical situations. Magnetic resonance imaging (MRI) is based on the absorption and emission of radiofrequency energy by hydrogen protons whose spin is influenced by changing magnetic fields (0.3 to 1.5 T). Unlike computed tomography (CT), there is no radiation exposure. T1-weighted images cause fat (eg, myelin in white matter) to appear bright and water (eg, cerebrospinal fluid [CSF] or edema) to appear dark on this sequence. The gray-white interfaces of the brain are well depicted on these sequences, especially if with the images are thinly sliced. T2-weighted images cause water (eg, CSF and edema) to appear bright and fat to appear dark. The MRI-based intravenous contrast agents (eg, gadolinium) are frequently used in T1-weighted images (Fig 1A and B) to make serum appear bright. The blood-brain barrier typically serves to limit the passage of many molecules out of the blood vessels. If disease processes break down this barrier (such as infection, tumors, or inflammation), intravenous contrast agents can cross into the brain, causing areas of contrast entry to appear very bright. Figure 1. T1-weighted image at the level of midbrain. A. The cerebrospinal fluid (CSF) appears dark. B. The CSF appears bright. Note the gray and white matter differentiation …

Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images

White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH), and we establish the I O -V WMH relationship. Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311ml (bias and 95% confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency.

Coexisting cytotoxic and vasogenic edema in Wernicke encephalopathy

Wernicke encephalopathy (WE) is caused by a thiamine deficiency and typically results in symmetrical lesions in areas of the brain including the paraventricular regions of the thalamus and hypothalamus, the mammillary bodies, the periaqueductal region of the midbrain, the floor of the fourth ventricle and the superior cerebellar vermis. We observed a case of WE that exhibited simultaneous cytotoxic and vasogenic edema. Although cytotoxic edema and vasogenic edema are typical findings of Wernicke encephalopathy, it is very rare for both pathogenic findings to be observed together. A 52-year-old woman with a history of total colectomy was admitted for management of epigastric discomfort, nausea and vomiting 7 days in duration. The patient suffered from recurrent paralytic ileus due to systemic sclerosis. Three months prior to admission, the patient underwent a total colectomy due to colon obstruction. The patient had no prior history of hypertension, diabetes, or cerebrovascular diseases. She did not have a history of smoking or alcohol consumption (Fig. 1). Despite administration of antiemetics, vomiting persisted. The patient was treated with intravenous glucose and electrolyte solution without vitamin supplementation. After 15 days of hospitalization, the patient was referred to the Neurology Department for evaluation of convulsive movement, diplopia, and ataxia. On examination, the patient was alert, but disoriented. There was complete ophthalmoplegia with coarse spontaneous nystagmus. The upper and lower limbs were symmetrically hypotonic and weak. The patient was unable to maintain a sitting position or standing position without support due to truncal ataxia, and deep tendon reflexes were slightly depressed. Laboratory studies revealed anemia, leukocytosis and elevated liver enzymes. The serum thiamine level was below the normal range (14.5 lg/L, normal 28–85). Magnetic resonance imaging (MRI) performed on the referral day showed high signal intensity lesions in both medial thalami, the mammillary bodies, the periaqueductal region, the tectum of the midbrain and the medullary tegmentum in T2-weighted and fluid-attenuated inversion recovery (FLAIR) MR imaging. Diffusion-weighted images (DWI) showed more extensive symmetrical high signal intensities in the aforementioned areas, and also in both the central and precentral sulcus. Apparent diffusion coefficient (ADC) mapping showed low intensity areas in both cortical sulcal lesions, the most medial part of the thalami, the mammillary bodies, and the dorsal and upper part of the midbrain tectum, and simultaneous high or iso intensities in the rest of the medial thalamus, midbrain tectum and medullary tegmentum. The patient was given 100 mg of thiamine per day intravenously. Seven days after thiamine supplementation, her ocular motor function had improved, and 21 days after thiamine treatment began, the patient was able to walk without titubation. Many case investigations using DWI to examine patients with Wernicke encephalopathy have S. Kim S.-H. Kim J.-S. Kim (&) Department of Neurology, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, 505, Banpo-dong, Seocho-gu, Seoul 137-701, South Korea e-mail: neuronet@catholic.ac.kr

脳梁離断症候群を示したインフルエンザワクチン接種後急性散在性脳脊髄炎の1例

We present a case of callosal disconnection syndrome as a rare manifestation of acute disseminated encephalomyelitis (ADEM). A dextral 48-year-old Japanese woman received trivalent inactivated influenza vaccine in mid-November 2011. Twenty days later, she was found to be in a daze. Subsequently, she developed abnormal behavior and gait disturbance, and she was disoriented regarding time and place. Nystagmus and abnormal ocular movements were absent. Upper limb power was normal, whereas her lower limbs were mildly weak. Tendon reflexes were normally evoked without pathological reflexes. There was no sensory impairment. Serum CRP levels were slightly elevated; other routine laboratory tests, thyroid functions, and vitamin B1 levels were within the normal range. Cerebrospinal fluid examination revealed that it was acellular with a protein level of 54 mg/dl and high myelin basic protein level. Fluid-attenuated inversion recovery MR images revealed a large hyperintense lesion in the corpus callosum, but the lower part of the splenium was spared. Flow voids were observed in the pericallosal arteries. She was diagnosed with post-vaccination ADEM and vigorously treated with an intravenous infusion of methylprednisolone (1 g/day for 6 days) and immunoglobulin (1.2 g/kg). Gait disturbance and disorientation rapidly improved; however, tactile anomia, ideomotor apraxia, ideational apraxia, and agraphia of the left hand were present one month after onset. She had no aphasia or alexia.Interestingly, the patient's left unilateral agraphia was more prominent in kana than kanji (an article in Japanese text) for polysyllabic words, whereas she could write kana characters to dictation. Changes in the sequential order of kana characters within a word were observed. These findings were similar to those observed in pure agraphia associated with lesions in the posterior part of the left middle frontal gyrus. Thus, an interhemispheric mechanism is probably involved in the selection and arrangement of kana characters to form words.

Longitudinal relaxographic imaging of white matter hyperintensities in the elderly.

BackgroundIncidental white matter hyperintensities (WMHs) are common findings on T2-weighted magnetic resonance images of the aged brain and have been associated with cognitive decline. While a variety of pathogenic mechanisms have been proposed, the origin of WMHs and the extent to which lesions in the deep and periventricular white matter reflect distinct etiologies remains unclear. Our aim was to quantify the fractional blood volume (vb) of small WMHs in vivo using a novel magnetic resonance imaging (MRI) approach and examine the contribution of blood–brain barrier disturbances to WMH formation in the deep and periventricular white matter.MethodsTwenty-three elderly volunteers (aged 59–82 years) underwent 7 Tesla relaxographic imaging and fluid-attenuated inversion recovery (FLAIR) MRI. Maps of longitudinal relaxation rate constant (R1) were prepared before contrast reagent (CR) injection and throughout CR washout. Voxelwise estimates of vb were determined by fitting temporal changes in R1 values to a two-site model that incorporates the effects of transendothelial water exchange. Average vb values in deep and periventricular WMHs were determined after semi-automated segmentation of FLAIR images. Ventricular permeability was estimated from the change in CSF R1 values during CR washout.ResultsIn the absence of CR, the total water fraction in both deep and periventricular WMHs was increased compared to normal appearing white matter (NAWM). The vb of deep WMHs was 1.8 ± 0.6 mL/100 g and was significantly reduced compared to NAWM (2.4 ± 0.8 mL/100 g). In contrast, the vb of periventricular WMHs was unchanged compared to NAWM, decreased with ventricular volume and showed a positive association with ventricular permeability.ConclusionsHyperintensities in the deep WM appear to be driven by vascular compromise, while those in the periventricular WM are most likely the result of a compromised ependyma in which the small vessels remain relatively intact. These findings support varying contributions of blood–brain barrier and brain-CSF interface disturbances in the pathophysiology of deep and periventricular WMHs in the aged human brain.

Potential of fluid-attenuated inversion recovery MRI as an alternative to contrast-enhanced MRI for oral and maxillofacial vascular malformations: experimental and clinical studies

To determine the potential of fluid-attenuated inversion recovery (FLAIR) imaging of oral and maxillofacial vascular malformations as an alternative to contrast-enhanced magnetic resonance imaging (MRI), we investigated the influence of differences in T1 and T2 values on image contrast in FLAIR images and evaluated the diagnostic utility of such images. FLAIR imaging and heavily T2-weighted (hT2-weighted) imaging were performed using a phantom. FLAIR and hT2-weighted images of 32 lesions (11 mucous cysts, 12 vascular malformations, and 9 tumors) were also studied retrospectively. The contrast-to-noise ratios (CNRs) and CNR change ratios were compared. All aqueous solutions except those with a short T2 value were discriminated by CNR change ratio (P<.05). All 3 types of lesions were discriminated by CNR change ratio (P<.05). FLAIR imaging has potential as an alternative to contrast-enhanced MRI in differentiating vascular malformations from other types of lesions in the oral and maxillofacial region.

Audiovestibular Characteristics of Small Cochleovestibular Schwannomas in Neurofibromatosis Type 2

Objectives: Describe the relationship between cochleovestibular schwannoma (CVS) volume, audiovestibular changes, and magnetic resonance imaging (MRI) findings in patients with neurofibromatosis Type 2 (NF-2). Methods: Subgroup analysis of NF-2 prospective natural history study from June 2008 to June 2011. Subjects: NF-2 patients with small treatment- naïve CVS (volume &lt; 1cm3) by ear. N = 49 ears, 32 patients. Setting: Quaternary medical research institute. Intervention: None. Outcome Measurements: Tumor size, auditory brainstem response (ABR), audiogram (4-frequency PTA - 0.5, 1, 2, 4KHz), vestibular evoked myogenic potential (VEMP), caloric videonystagmography (VNG), rotary chair testing (240°/sec velocity step test), and magnetic resonance imaging (MRI) findings. Results: Larger tumor volume (mean 0.489cm3; 95% confidence interval [CI] 0.313-0.664) correlated with abnormal ABR findings, compared to smaller tumors with normal ABR (mean 0.151cm3; 95%CI 0.89-0.213). Larger tumors also correlated with weak caloric response (mean 0.520cm3; 95%CI 0.300-0.741 vs. mean 0.199cm3; 95%CI 0.102-0.296). Tumor volume was not significantly correlated with PTA, VEMP, or rotary chair testing. Elevated intralabyrinthine protein on MRI fluid-attenuated inversion recovery sequences was correlated with larger tumor size (mean volume 0.331cm3; 95%CI 0.246-0.419 vs. 0.055cm3; 95%CI 0.008-0.103) and abnormal ABR and PTA ( P &lt; 0.05), but it did not correlate with VEMP or caloric responses. Conclusions: In our sample, ABR, caloric response, and intralabyrinthine protein correlated with tumor volume, but PTA, VEMP, and high velocity step testing did not. Abnormal ABR and PTA were correlated with elevated protein. These findings may provide insight on the effect of small CVS on the inner ear and cochleovestibular nerves, which may aid in their management.

Neuroimaging of six neurosyphilis cases mimicking viral encephalitis

BackgroundNeurosyphilis is known as “the great imitator” due to its wide range of clinical symptoms and abnormalities upon magnetic resonance imaging (MRI). Typical findings of both neurosyphilis and viral encephalitis include unilateral or bilateral MR hyperintensities in mesiotemporal lobes upon T2-weighted imaging or fluid attenuation inversion recovery (FLAIR) imaging. Accordingly, patients with neurosyphilis are frequently misdiagnosed with viral encephalitis, which prevents them from receiving appropriate treatment and often results in greater neurologic damage. MethodsClinical characteristics and MRI changes of 6 neurosyphilis patients admitted to our hospital between March 2012 and November 2012 were retrospectively reviewed. ResultsAll 6 cases were tested positive for assays measuring Treponema pallidum hemagglutination (TPHA), rapid plasma reagin (RPR), and antibodies against syphilis in the serum and cerebrospinal fluid (CSF). Likewise, all patients were negative for antibodies against viral pathogens. T2-weighted or FLAIR MRI of the brains in all cases revealed either unilateral or bilateral hyperintensities in the mesiotemporal lobes, including the hippocampi. Electroencephalography showed relevant, localized slow or spiked waves. Patient prognoses were good in the 4 cases that received early anti-syphilis treatment, but the 2 cases that received delayed treatment due to misdiagnoses did not see substantial symptomatic improvements. ConclusionsNeurosyphilis should be considered when there is mesiotemporal involvement upon MRI. Early treatment for syphilis is critical for positive outcomes.

The Leptomeningeal Ivy Sign on Fluid-Attenuated Inversion Recovery Images in Moyamoya Disease: Positron Emission Tomography Study

Background: The ivy sign is sometimes seen on fluid-attenuated inversion recovery (FLAIR) images in moyamoya disease (MMD). In recent studies using single-photon emission computed tomography, ivy sign proliferation correlated with decreases in cerebrovascular reserve. However, a decreased vascular reserve is not concrete. The purpose of this study was to evaluate the correlation between ivy sign proliferation and the findings of ¹⁵O gas positron emission tomography (PET). Methods: In 19 MMD patients (12 women, age 31-69 years) with ischemic symptoms, FLAIR magnetic resonance imaging and ¹⁵O gas PET were performed. We classified the middle cerebral artery (MCA) territory into 2 regions in each hemisphere, and the degree of the ivy sign (ivy sign score) in each region was classified into 3 grades (0-2), where grade 0 indicated an absence of the ivy sign, grade 1 indicated that the ivy sign was seen on less than half of the cortical surface in each region, and grade 2 indicated that the ivy sign was seen on more than half of the cortical surface. We examined the relationship among the ivy sign score, the severity of ischemic symptoms and PET parameters in 76 MCA regions of 19 patients. Results: Ivy sign scores of the regions were 0 (n = 19), 1 (n = 40), and 2 (n = 17). Total ivy sign score of a hemisphere increased as clinical symptoms became more severe. Cerebral blood flow (CBF) values were lower, cerebral blood volume (CBV) values were higher, and CBF/CBV values were lower than those of controls as symptoms became severe (p < 0.05). CBF and CBF/CBV values decreased and CBV values increased as the ivy sign score increased, and were significantly higher and lower, respectively, than control values (p < 0.05). No significant differences in cerebral metabolic rate of oxygen and oxygen extraction fraction were found between the 3 ivy sign scores. A positive correlation was found between ivy sign score and increases in CBV (p < 0.01), and a more obvious negative correlation was found between ivy sign score and decreases in CBF/CBV (p < 0.001). Conclusions: We evaluated the correlation between ivy sign proliferation and the findings of ¹⁵O gas PET. We suggested that ivy sign proliferation was associated with both dilated pial vasculature and the slow flow of developed leptomeningeal collaterals in patients with MMD.

Bevacizumab as a treatment for radiation necrosis of brain metastases post stereotactic radiosurgery

Cerebral radiation necrosis (RN) is a difficult to treat complication of stereotactic radiosurgery (SRS) that can result in progressive neurologic decline. Currently, steroids are the standard of care treatment for brain RN despite their adverse effect profile and limited efficacy. The purpose of this study was to evaluate the treatment efficacy of cerebral RN to bevacizumab in patients with brain metastases previously treated with SRS. We retrospectively reviewed 14 lesions in 11 patients treated with bevacizumab for brain RN secondary to SRS for their brain metastases. Steroid dosing, RN-associated symptoms, and magnetic resonance imaging (MRI) scans were examined before, during, and after bevacizumab administration. Of the 11 patients included, 6 had metastatic non-small cell lung cancer, and 5 had metastatic breast cancer. The mean percentage decrease in RN volume seen on T1 post-Gadolinium and fluid-attenuated inversion recovery (FLAIR) MRI at first follow-up, at a mean of 26 days (range, 15-43 days), was 64.4% and 64.3%, respectively. MRI changes were sustained on follow-up MRI scans, obtained at a mean of 33 days (range, 7-58 days) after bevacizumab discontinuation. After bevacizumab treatment, all patients initially receiving steroids had a reduction in steroid requirement, and all but one had an improvement in or stability of RN-associated symptoms. No patients experienced intratumoral bleeds or other adverse effects related to their bevacizumab treatment. Bevacizumab is effective and safe for the treatment of RN after SRS for brain metastasis. In this context, bevacizumab offers symptomatic relief, a reduction in steroid requirement, and a dramatic radiographic response.

Increasing the contrast of the brain MR FLAIR images using fuzzy membership functions and structural similarity indices in order to segment MS lesions.

Segmentation is an important step for the diagnosis of multiple sclerosis (MS). This paper presents a new approach to the fully automatic segmentation of MS lesions in Fluid Attenuated Inversion Recovery (FLAIR) Magnetic Resonance (MR) images. With the aim of increasing the contrast of the FLAIR MR images with respect to the MS lesions, the proposed method first estimates the fuzzy memberships of brain tissues (i.e., the cerebrospinal fluid (CSF), the normal-appearing brain tissue (NABT), and the lesion). The procedure for determining the fuzzy regions of their member functions is performed by maximizing fuzzy entropy through Genetic Algorithm. Research shows that the intersection points of the obtained membership functions are not accurate enough to segment brain tissues. Then, by extracting the structural similarity (SSIM) indices between the FLAIR MR image and its lesions membership image, a new contrast-enhanced image is created in which MS lesions have high contrast against other tissues. Finally, the new contrast-enhanced image is used to segment MS lesions. To evaluate the result of the proposed method, similarity criteria from all slices from 20 MS patients are calculated and compared with other methods, which include manual segmentation. The volume of segmented lesions is also computed and compared with Gold standard using the Intraclass Correlation Coefficient (ICC) and paired samples t test. Similarity index for the patients with small lesion load, moderate lesion load and large lesion load was 0.7261, 0.7745 and 0.8231, respectively. The average overall similarity index for all patients is 0.7649. The t test result indicates that there is no statistically significant difference between the automatic and manual segmentation. The validated results show that this approach is very promising.