3D Fluid-attenuated Inversion Recovery Research Articles

Age independently affects myelin integrity as detected by magnetization transfer magnetic resonance imaging in multiple sclerosis.

BackgroundMultiple sclerosis (MS) is a heterogeneous disorder with a progressive course that is difficult to predict on a case-by-case basis. Natural history studies of MS have demonstrated that age influences clinical progression independent of disease duration.ObjectiveTo determine whether age would be associated with greater CNS injury as detected by magnetization transfer MRI.Materials and methodsForty MS patients were recruited from out-patient clinics into two groups stratified by age but with similar clinical disease duration as well as thirteen controls age-matched to the older MS group. Images were segmented by automated programs and blinded readers into normal appearing white matter (NAWM), normal appearing gray matter (NAGM), and white matter lesions (WMLs) and gray matter lesions (GMLs) in the MS groups. WML and GML were delineated on T2-weighted 3D fluid-attenuated inversion recovery (FLAIR) and T1 weighted MRI volumes. Mean magnetization transfer ratio (MTR), region volume, as well as MTR histogram skew and kurtosis were calculated for each region.ResultsAll MTR measures in NAGM and MTR histogram metrics in NAWM differed between MS subjects and controls, as expected and previously reported by several studies, but not between MS groups. However, MTR measures in the WML did significantly differ between the MS groups, in spite of no significant differences in lesion counts and volumes.ConclusionsDespite matching for clinical disease duration and recording no significant WML volume difference, we demonstrated strong MTR differences in WMLs between younger and older MS patients. These data suggest that aging-related processes modify the tissue response to inflammatory injury and its clinical outcome correlates in MS.

Fluid-attenuated inversion recovery vascular hyperintensities are not visible using 3D CUBE FLAIR sequence

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH), initially described on 2D FLAIR images, are a useful imaging marker in patients with acute ischaemic stroke. We aimed to compare the sensitivity of the 3D CUBE FLAIR sequence with 2D FLAIR for the detection of FVH. Forty-seven consecutive patients admitted for a suspected stroke were explored by 2D and 3D CUBE FLAIR MR sequences at 1.5 and 3 T. Three blinded readers assessed FVH defined as hyperintensities within cerebral arteries. Location of FVH, acute brain infarct and arterial stenosis were also assessed. 2D images were compared with 3D images for the detection of FVH. Agreement between readers was assessed. Of the 47 patients, 21 FVHs were observed on 2D FLAIR images of 15 patients (11 with acute brain infarct and 11 with an arterial stenosis). No FVH was visualised on 3D CUBE FLAIR images for either proximal or distal locations. Agreement between readers was excellent. FVHs are not visible using 3D CUBE FLAIR images. This study suggests that, in suspected acute ischaemic stroke, the assessment of FVH should only be performed on conventional 2D FLAIR images. • Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are of neuroradiological importance. • FVHs are useful imaging markers in patients with an acute ischaemic stroke. • FVHs are not visible using 3D CUBE FLAIR images. • Assessment of FVH should be performed on conventional 2D FLAIR images.

Abstract WP214: Cortical Microinfarcts as a Putative MRI Marker for Cerebral Amyloid Angiopathy

Background: Cortical microinfarcts (CMIs) are frequently detected in autopsy brains of elderly subjects, and distributed predominantly in the area of predilection for cerebral amyloid angiopathy (CAA). Recently these lesions have been detected on high-filed MRI using double inversion recovery (DIR) and 3D-fluid attenuated inversion recovery (FLAIR). Radiological diagnosis according to Boston criteria for CAA may be reinforced by detecting CMIs. Methods: We performed a prospective analysis of 36 patients diagnosed as clinically probable CAA by Boston criteria, including multiple strictly lobar microbleeds as a diagnostic indicator. These patients were recruited at the Department of Neurology, Mie University Hospital from August 2009 to April 2012. 3-tesla MR images including susceptibility-weighted imaging (SWI), DIR and 3D- FLAIR were reviewed. Results: CMIs were found in 9 of 36 (25%) patients. Most CMIs were located in close proximity to lobar microbleeds. Cortical superficial siderosis was observed in 6 of 36 (16.6%) patients, among which 5 (83.3%) showed CMIs. There were 5 patients with symptomatic subcortical hemorrhage, and 3 of these (60%) showed both CMIs and superficial siderosis. Conclusions: These results indicate that CMIs strengthen radiological diagnosis of CAA if these lesions coexist with multiple strictly lobar microbleeds and cortical superficial siderosis.

Estimation of Perilymph Enhancement after Intratympanic Administration of Gd-DTPA by Fast T1-mapping with a Dual Flip Angle 3D Spoiled Gradient Echo Sequence

Eleven patients with suspected Ménière's disease received intratympanic (IT) administration of gadolinium (gadopentetate dimeglumine; Gd) prior to acquisition of 3-dimensional (3D) fluid-attenuated inversion recovery (FLAIR), 3D real inversion recovery (IR), and fast T₁ mapping by dual flip angle 3D gradient echo (FT₁-map) imaging sequences to evaluate the degree of perilymph enhancement. Though 3-dimensional FLAIR could detect lower concentrations of gadolinium than 3D real IR, in 2 patients, poor enhancement still prevented visualization of the endolymphatic space using 3D FLAIR. We could predict poor contrast enhancement in these 2 patients using the FT₁-map technique.

Semi-quantification of Endolymphatic Size on MR Imaging after Intravenous Injection of Single-dose Gadodiamide: Comparison between Two Types of Processing Strategies

Many inner ear disorders, including Ménière's disease, are believed to be based on endolymphatic hydrops. We evaluated a newly proposed method for semi-quantification of endolymphatic size in patients with suspected endolymphatic hydrops that uses 2 kinds of processed magnetic resonance (MR) images. Twenty-four consecutive patients underwent heavily T2-weighted (hT2W) MR cisternography (MRC), hT2W 3-dimensional (3D) fluid-attenuated inversion recovery (FLAIR) with inversion time of 2250 ms (positive perilymph image, PPI), and hT2W-3D-IR with inversion time of 2050 ms (positive endolymph image, PEI) 4 hours after intravenous administration of single-dose gadolinium-based contrast material (IV-SD-GBCM). Two images were generated using 2 new methods to process PPI, PEI, and MRC. Three radiologists contoured the cochlea and vestibule on MRC, copied regions of interest (ROIs) onto the 2 kinds of generated images, and semi-quantitatively measured the size of the endolymph for the cochlea and vestibule by setting a threshold pixel value. Each observer noted a strong linear correlation between endolymphatic size of both the cochlea and vestibule of the 2 kinds of generated images. The Pearson correlation coefficients (r) were 0.783, 0.734, and 0.800 in the cochlea and 0.924, 0.930, and 0.933 in the vestibule (P<0.001, for all). In both the cochlea and vestibule, repeated-measures analysis of variance showed no statistically significant difference between observers. Use of the 2 kinds of generated images generated from MR images obtained 4 hours after IV-SD-GBCM might enable semi-quantification of endolymphatic size with little observer dependency.

Clinical application of multi-contrast 7-T MR imaging in multiple sclerosis: increased lesion detection compared to 3 T confined to grey matter

Seven-Tesla MRI demonstrated new pathological features of multiple sclerosis (MS) using T2-weighted sequences. However, a clinical MRI protocol at 7 T has never been investigated. We evaluated the clinical value of 7-T MRI by investigating the sensitivity of lesion detection compared with 3 T. Thirty-eight MS patients and eight healthy controls underwent multi-contrast MRI using 3D T1-weighted (3D-T1w), 2D dual-echo T2-weighted (2D-T2w) and 3D fluid-attenuated inversion recovery (3D-FLAIR) at 3 and 7 T. Images were analysed for focal lesions, which were counted and categorised according to anatomical location. The study was approved by the institutional review board. Lesion-wise analysis showed increased lesion counts in cortical grey matter (GM) at 7 T of 91, 75 and 238 % for 3D-T1w, 2D-T2w and FLAIR sequences, respectively. Patient-wise analysis confirmed this for 2D-T2w and FLAIR (P < 0.023 and P < 0.001). Seven-Tesla white matter (WM) lesion detection was not increased; 3D-FLAIR even detected significantly more WM lesions at 3 T. Using a clinical multi-contrast MRI protocol, increased lesion detection was observed in cortical GM but not in WM. Given the clinical relevance of GM abnormalities, this may have consequences for clinical outcome measures, prognostic classification and future diagnostic criteria incorporating GM abnormalities.

Pitfalls of 3D FLAIR Brain Imaging: A Prospective Comparison with 2D FLAIR

To prospectively compare the image contrast of various brain lesions on two-dimensional (2D) and three-dimensional (3D) fluid-attenuated inversion-recovery (FLAIR) images and to highlight the pitfalls of 3D FLAIR. Institutional review board approval was obtained. We examined 94 brain lesions with 2D and 3D FLAIR at 3T. First, we optimized the repetition time and echo time of 3D FLAIR with a volunteer study. Then, we assessed the conspicuity and detection of the various lesions qualitatively, and the contrast ratio between the gray or white matter and lesions was calculated as a quantitative assessment. We also performed a phantom study to investigate the effects of different flow velocities on 2D and 3D FLAIR. With regard to the conspicuity and detection of most lesions (multiple sclerosis, ischemic lesions or infarction, brain tumors, or chronic trauma), 3D FLAIR was equal or superior to 2D FLAIR. For these lesions, the mean contrast ratios were higher on 3D FLAIR than on 2D FLAIR images. In terms of lesion conspicuity in the patients with hippocampal sclerosis and leptomeningeal metastasis, however, 3D FLAIR was equal or inferior to 2D FLAIR. The ivy sign in patients with moyamoya disease was frequently obscured on 3D FLAIR. The phantom study demonstrated that the signal-intensity ratio on 3D FLAIR decreased more rapidly with increasing velocity than that on 2D FLAIR. Although 3D FLAIR may replace 2D FLAIR images for most patients, radiologists should keep in mind that 3D has some pitfalls.

MP2RAGE Multiple Sclerosis Magnetic Resonance Imaging at 3 T

Lesion detection and characterization in multiple sclerosis (MS) are an essential part of its clinical diagnosis and an important research field. In this pilot study, we applied the recently introduced two inversion-contrast magnetization-prepared rapid gradient echo sequence (MP2RAGE) to patients with early-stage MS. The MP2RAGE is a 3-dimensional (3D) magnetization-prepared rapid gradient echo derivative providing homogeneous T1 weighting and simultaneous T1 mapping. The MP2RAGE performance was compared with that of 2 clinical routine sequences (2D fluid-attenuated inversion recovery [FLAIR] and 3D magnetization-prepared rapid gradient echo [MP-RAGE]) and 2 state-of-the art clinical research sequences (the 3D FLAIR-SPACE [sampling perfection with application-optimized contrasts by using different flip-angle evolutions], a fluid-attenuated variable flip-angle fast spin echo technique, and the 3D double-inversion recovery SPACE). A cohort of 10 early-stage female MS patients (age, 31.6 ± 4.7 years; disease duration, 3.8 ± 1.9 years; median expanded disability status scale score, 1.75) and 10 age- and gender-matched controls were enrolled after approval of the local institutional review board was obtained. Multiple sclerosis lesions were identified and assigned to brain locations and tissue types by two experienced physicians in all 5 contrasts. Subsequently, lesions were manually delineated for comparison and statistical analysis of lesion count, volume and quantitative measures. The results show that the 3D T1-weighted high-resolution MP2RAGE contrast provides a sensitive means for MS lesion assessment. The additional quantitative T1 relaxation time maps obtained with the MP2RAGE provide further potential diagnostic and prognostic information that could help (a) to better discriminate lesion subtypes and (b) to stage and predict the activity and the evolution of MS. Results also indicate that the T2-weighted double-inversion recovery and FLAIR-SPACE contrasts are attractive complements to the MP2RAGE for lesion detection.

Ultrahigh-Field MRI in Human Ischemic Stroke – a 7 Tesla Study

IntroductionMagnetic resonance imaging (MRI) using field strengths up to 3 Tesla (T) has proven to be a powerful tool for stroke diagnosis. Recently, ultrahigh-field (UHF) MRI at 7 T has shown relevant diagnostic benefits in imaging of neurological diseases, but its value for stroke imaging has not been investigated yet. We present the first evaluation of a clinically feasible stroke imaging protocol at 7 T. For comparison an established stroke imaging protocol was applied at 3 T.MethodsIn a prospective imaging study seven patients with subacute and chronic stroke were included. Imaging at 3 T was immediately followed by 7 T imaging. Both protocols included T1-weighted 3D Magnetization-Prepared Rapid-Acquired Gradient-Echo (3D-MPRAGE), T2-weighted 2D Fluid Attenuated Inversion Recovery (2D-FLAIR), T2-weighted 2D Fluid Attenuated Inversion Recovery (2D-T2-TSE), T2* weighted 2D Fast Low Angle Shot Gradient Echo (2D-HemoFLASH) and 3D Time-of-Flight angiography (3D-TOF).ResultsThe diagnostic information relevant for clinical stroke imaging obtained at 3 T was equally available at 7 T. Higher spatial resolution at 7 T revealed more anatomical details precisely depicting ischemic lesions and periinfarct alterations. A clear benefit in anatomical resolution was also demonstrated for vessel imaging at 7 T. RF power deposition constraints induced scan time prolongation and reduced brain coverage for 2D-FLAIR, 2D-T2-TSE and 3D-TOF at 7 T versus 3 T.ConclusionsThe potential of 7 T MRI for human stroke imaging is shown. Our pilot study encourages a further evaluation of the diagnostic benefit of stroke imaging at 7 T in a larger study.

Automated quantification of white matter disease extent at 3 T: Comparison with volumetric readings

To develop and validate an algorithm to automatically quantify white matter hyperintensity (WMH) volume. Images acquired as part of the Dallas Heart Study, a multiethnic, population-based study of cardiovascular health, were used to develop and validate the algorithm. 3D magnetization prepared rapid acquisition gradient echo (MP-RAGE) and 2D fluid-attenuated inversion recovery (FLAIR) images were acquired from 2082 participants. Images from 161 participants (7.7% of the cohort) were used to set an intensity threshold to maximize the agreement between the algorithm and a qualitative rating made by a radiologist. The resulting algorithm was run on the entire cohort and outlier analyses were used to refine the WMH volume measurement. The refined, automatic WMH burden estimate was then compared to manual quantitative measurements of WMH volume in 28 participants distributed across the range of volumes seen in the entire cohort. The algorithm showed good agreement with the volumetric readings of a trained analyst: the Spearman's Rank Order Correlation coefficient was r = 0.87. Linear regression analysis showed a good correlation WMHml[automated] = 1.02 × WMHml[manual] - 0.48. Bland-Altman analysis showed a bias of 0.34 mL and a standard deviation of 2.8 mL over a range of 0.13 to 41 mL. We have developed an algorithm that automatically estimates the volume of WMH burden using an MP-RAGE and a FLAIR image. This provides a tool for evaluating the WMH burden of large populations to investigate the relationship between WMH burden and other health factors.

Generalized Multiple-Layer Appearance of the Cerebral Cortex with 3D FLAIR 7.0-T MR Imaging

To examine the multiple-layer appearance of the cerebral cortex with fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging at 7.0 T, whole-brain volumetric three-dimensional (3D) magnetization prepared FLAIR images were acquired in 12 volunteers (0.8 3 0.8 3 0.8-mm spatial resolution). Signal intensity profiles were evaluated for the anterior frontal (Brodmann area [BA] 10), posterior frontal (BA 6), parietal (BA 7), precentral (BA 4), postcentral (BA 3), occipital (BA 18), and calcarine (BA 17) regions. Variance of the normalized profile was used as the metric for the multiple-layer appearance. Wilcoxon signed-rank tests were performed to compare variances of the profiles between all areas. All cortical areas showed multiple-layered appearances, with a prominent hyperintense band at the external surface of the cortex, a hypointense band deeper in the cortex, and a hyperintense third band. The ranking from least- to most-pronounced layer appearance was as follows: postcentral (variance, 0.04), posterior frontal (variance, 0.05), calcarine (variance, 0.05), precentral (variance, 0.06), parietal (variance, 0.08), anterior frontal (variance, 0.10), and occipital (variance, 0.11). Each region was significantly different from at least one other region. In conclusion, a multiple-layer appearance of the cerebral cortex was found for all cortical regions with high-spatial-resolution 3D FLAIR MR imaging at 7.0 T.

Postmortem verification of MS cortical lesion detection with 3D DIR

To assess the sensitivity and specificity of 3D double inversion recovery (DIR) MRI for detecting multiple sclerosis (MS) cortical lesions (CLs) using a direct postmortem MRI to histopathology comparison. Single-slab 3D DIR and 3D fluid-attenuated inversion recovery (FLAIR) images of 56 matched fresh brain samples from 14 patients with chronic MS were acquired at 1.5 T. The images of both sequences were prospectively scored for CLs in consensus by 3 experienced raters who were blinded to histopathology and clinical data. Next, CLs were identified histopathologically and were scored again on 3D DIR and 3D FLAIR (retrospective scoring). CLs were classified as intracortical or mixed gray matter (GM)-white matter lesions. Deep GM lesions were also scored. False-positive scores were noted and, from this, specificity was calculated. We found a sensitivity for 3D DIR to detect MS CLs of 18%, which is 1.6-fold higher than 3D FLAIR (improves to 37% with retrospective scoring; 2.0-fold higher than 3D FLAIR). We detected mixed GM-white matter lesions with a sensitivity of 83% using 3D DIR (65% sensitivity for 3D FLAIR), which improved to 96% upon retrospective scoring (91% for 3D FLAIR). For purely intracortical lesions, 3D DIR detected more than 2-fold more than 3D FLAIR (improved to >3-fold upon retrospective scoring). The specificity of 3D DIR to MS CLs was found to be 90%. In this postmortem verification study, we have shown that 3D DIR is highly pathologically specific, and more sensitive to CLs than 3D FLAIR in MS.

Imaging of Endolymphatic and Perilymphatic Fluid after Intravenous Administration of Single-dose Gadodiamide

To visualize endolymph as bright signal after intravenous injection of single-dose gadodiamide, we shortened the inversion time of heavily T(2)-weighted 3-dimensional (3D) fluid-attenuated inversion recovery (FLAIR) to 2050 ms. In 14 patients with suspected Ménière's disease, we observed high signal of vestibular endolymph in all ears, including 6 ears without vestibular endolymphatic hydrops. We observed high signal of cochlear endolymph in 17 ears with cochlear endolymphatic hydrops but not 11 ears without cochlear endolymphatic hydrops.

3D FLAIRED: 3D fluid attenuated inversion recovery for enhanced detection of lesions in multiple sclerosis

Contrast optimization of a three-dimensional (3D) Fluid-attenuated inversion recovery (FLAIR) sequence is examined in the context of multiple sclerosis. In order to develop 3D FLAIR for enhanced detection of lesions, an iterative approach based on theoretical considerations was used. The 3D FLAIR sequence was systematically acquired with incremental parameter changes on a single subject with multiple sclerosis in a 3-T MRI scanner. Region of interest analysis was performed on the images, and the best estimate of the optimal acquisition parameters was established. This process was iterated on subsequent patients with multiple sclerosis until only marginal gains in quality were obtained. Three-dimensional FLAIR for enhanced detection produced increased lesion detection and identification in the supratentorial and infratentorial regions when compared with default GE 3D FLAIR and two-dimensional FLAIR sequences. Lesion border delineation was enhanced as evidenced by better lesion and white matter contrast ratios, demonstrating that the approach is a viable method for improved lesion detection.

3D Fluid-Attenuated Inversion Recovery Imaging: Reduced CSF Artifacts and Enhanced Sensitivity and Specificity for Subarachnoid Hemorrhage

FLAIR images are highly sensitive for SAH. However, CSF flow artifacts caused by conventional FLAIR can produce false-positive results. Here, we compare 3D and 3D FLAIR sequences, focusing on their potential for containing these artifacts and their sensitivity and specificity for detection of SAHs. We evaluated the following 4 FLAIR sequences: 1) 2D FLAIR at 1.5T, 2) 2D FLAIR, 3) 2D PROPELLER-FLAIR, and 4) 3D Cube-FLAIR at 3T. All sequences were performed in 5 healthy volunteers; sequences 2 and 4 were also performed under routine conditions in 10 patients with focal epilepsy and in 10 patients with SAH. Two neuroradiologists independently conducted the analysis. The presence of flow artifacts in the ventricles and cisterns of healthy volunteers and patients with epilepsy was evaluated and scored on a 4-point scale. Mean values were calculated and compared by using paired t tests. Sensitivity and specificity for SAH detection in sequences 2 and 4 were determined. Cube-FLAIR showed almost no CSF artifacts in the volunteers and the patients with epilepsy; therefore, it was superior to any other FLAIR (P < .001). Sensitivity and specificity of SAH detection by 3T FLAIR were 58.3% and 89.4%, respectively, whereas Cube-FLAIR had a sensitivity of 95% and a specificity of 100%. Cube-FLAIR allows FLAIR imaging with almost no CSF artifacts and is, thus, particularly useful for SAH detection.

Contrast enhancement of the inner ear after intravenous administration of a standard or double dose of gadolinium contrast agents

Conclusion. Imaging of the endolymphatic space was possible in most cases after administering a standard dose of gadolinium (Gd) by using heavily T2-weighted 3D fluid-attenuated inversion recovery (hT(2)W-3D-FLAIR) magnetic resonance imaging (MRI). Objectives. The aim of this study was to characterize the contrast enhancement in the inner ear after intravenous injection of Gd and to compare the signal intensity after a double dose or standard dose of Gd. Methods: We injected a standard dose of gadodiamide hydrate (DTPA-BMA) or a double dose of gadoteridol (HP-DO3A) intravenously in patients affected by Meniere's disease and performed hT(2)W-3D-FLAIR 3 T MRI. Contrast enhancement of the basal turn of the cochlea was evaluated semiquantitatively. Results: Endolymphatic hydrops was observed in the cochlea and vestibule of the affected ears of patients with Meniere's disease in both the double-dose group and the standard-dose group.

Transport Augmentation Through the Blood-Inner Ear Barriers of Guinea Pigs Treated With 3-Nitropropionic Acid and Patients With Acute Hearing Loss, Visualized With 3.0 T MRI

To visualize the permeability changes in the blood-inner ear barriers of guinea pigs with acute mitochondria dysfunction and in patients with acute hearing loss using contrast agent-enhanced MRI. An animal model of acute mitochondria dysfunction-induced hearing loss was created by introducing 3-nitropropionic acid (3-NP) intratympanically in guinea pigs. Vestibular disorder and hearing loss were evaluated. An MRI was performed at 2 h after either intravenous (IV) or intratympanic administration of dimeglumine gadopentetate (Gd-DTPA), using 3D fast-recovery fast spin-echo (FRFSE) and 3D fluid-attenuated inversion recovery (FLAIR) sequences. The inner ears of patients with acute hearing loss were imaged using a 3D-FLAIR sequence with a 3 T MRI machine at 2 h post-IV injection with Gd-DTPA at a routine dosage. Guinea pigs treated with 3-NP showed severe hearing loss and vestibular dysfunction. MR imaging with a 3D-FLAIR sequence at 2 h post-IV injection of Gd-DTPA was an optimal method for visualizing transport augmentation through the blood-inner ear barriers. Apoptosis appeared in the stria vascularis and Reissner's membrane of cochleae treated with 3NP. Similar MRI changes were observed in patients with SSHL and Ménière's disease 2 h post-IV injection with Gd-DTPA using the 3D-FLAIR sequence. Variations of Gd-DTPA transport through the blood-inner ear barriers induced by mitochondria toxin was visualized in guinea pigs using a clinical 3.0 T machine. IV injection of Gd-DTPA with 2 h of waiting time and imaging with 3D-FLAIR are optimal methods. The MRI observation of the inner ear in the animal model was translatable to patients with acute hearing loss, using an IV injection of Gd-DTPA at the routine dosage.

Endolympathic hydrops in patients with vestibular schwannoma: visualization by non-contrast-enhanced 3D FLAIR

Signal intensity of ipsilateral labyrinthine lymph fluid has been reported to increase in most cases with vestibular schwannoma (VS) on 3D fluid attenuated inversion recovery (FLAIR). The purpose of this study was twofold, (1) to evaluate if endolymphatic space can be recognized in the patients with VS on non-contrast-enhanced 3D-FLAIR images and (2) to know if the vertigo in the patients with VS correlates to vestibular endolymphatic hydrops. From the introduction of 32-channel head coil at 3 T in May 2008 to June 2010, 15 cases with unilateral VS were identified in the radiology report database. The two cases without a significant signal increase on 3D FLAIR were excluded. Resting 13 cases were retrospectively analyzed in regard to the recognition of endolymphatic hydrops in the cochlea and vestibule and to the correlation between the patients' symptoms and endolymphatic hydrops. In all cases, vestibular endolymphatic space can be recognized on non-contrast-enhanced 3D FLAIR. Cochlear endolymphatic space can be identified only in one case with significant hydrops. Vestibular hydrops was identified in four cases. Among these four cases, three had vertigo, and one had no vertigo. In those nine cases without hydrops, two had vertigo, and seven did not have vertigo. No significant correlation between vertigo and vestibular hydrops was found. Vestibular endolymphatic space can be recognized on non-contrast-enhanced 3D FLAIR. In some patients with VS, vestibular hydrops is seen; however, endolymphatic hydrops in the vestibule might not be the only responsible cause of vertigo in the patients with VS.

A change in the apparent diffusion coefficient after treatment with bevacizumab is associated with decreased survival in patients with recurrent glioblastoma multiforme.

The aim of this study was to determine the prognostic significance of changes in parameters derived from diffusion tensor imaging (DTI) that occur in response to treatment with bevacizumab and irinotecan in patients with recurrent glioblastoma multiforme. 15 patients with recurrent glioblastoma multiforme underwent serial 1.5 T MRI. Axial single-shot echo planar DTI was obtained on scans performed 3 days and 1 day prior to and 6 weeks after initiation of therapy with bevacizumab and irinotecan. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps were registered to whole brain contrast-enhanced three-dimensional (3D) spoiled gradient recalled and 3D fluid attenuation inversion recovery (FLAIR) image volumes. Anatomic image volumes were segmented to isolate regions of interest defined by tumour-related enhancement (TRE) and FLAIR signal abnormality (FSA). Mean ADC and mean FA were calculated for each region. A Bland-Altman repeatability coefficient was also calculated for each parameter based on the two pre-treatment studies. A patient was considered to have a change in FA or ADC after therapy if the difference between the pre- and post-treatment values was greater than the repeatability coefficient for that parameter. Survival was compared using a Cox proportional hazard model. DTI detected a change in ADC within FSA after therapy in nine patients (five in whom ADC was increased; four in whom it was decreased). Patients with a change in ADC within FSA had significantly shorter overall survival (p=0.032) and progression free survival (p=0.046) than those with no change. In patients with recurrent glioblastoma multiforme treated with bevacizumab and irinotecan, a change in ADC after therapy in FSA is associated with decreased survival.

Contrast Enhancement of the Anterior Eye Segment and Subarachnoid Space: Detection in the Normal State by Heavily T2-weighted 3D FLAIR

Fluid-attenuated inversion recovery (FLAIR) has been reported more sensitive than T(1)-weighted images in detecting low concentration gadolinium-based contrast media (GBCM) in fluid, and heavily T(2)-weighted (hT(2)W) 3-dimensional (3D) FLAIR has recently been reported even more sensitive than conventional 3D FLAIR. We investigated whether high signal of the anterior eye segment (AES) and subarachnoid space (SAS) in various locations as well as cerebrospinal fluid (CSF) in cisterns and ventricles can be detected on hT(2)W 3D FLAIR images obtained 4 hours after intravenous administration of GBCM in subjects without eye and SAS diseases. Ten patients suspected of having Ménière's disease underwent hT(2)W 3D FLAIR 4 hours after intravenous administration of single-dose GBCM to evaluate endolymphatic hydrops. We evaluated signal intensity of AES, SAS surrounding the optic nerve, SAS in Meckel's cave, CSF in the internal auditory canal, CSF in the prepontine cistern, CSF in the lateral and fourth ventricles, and lymph fluid in the cochlea by comparison with non-contrast images obtained in a separate group of 5 patients. The signal intensity of each structure was normalized by that of the pontine parenchyma. We observed no signal difference in images of the pontine parenchyma obtained before and after enhancement. Significant signal difference was seen in all structures except the lateral and fourth ventricles. Four hours after intravenous injection, GBCM can be detected by hT(2)W 3D FLAIR in various fluid-containing spaces, such as the AES and various SAS and CSF spaces.