Signal intensity of motor and sensory cortices on T2-weighted and FLAIR images: intraindividual comparison of 1.5T and 3T MRI

The non-linear correlation between the volume of cerebral white matter lesions and incidence of bipolar disorder: A secondary analysis of data from a cross-sectional study

Cerebral white matter lesions (WML) are major risk factors for bipolar disorder (BD). However, studies on the association between cerebral WML volume and BD risk are limited. This study aimed to investigate the relationship between cerebral WML volume and BD incidence. This is a secondary retrospective analysis of patients (N = 146, 72 males, 74 females, mean age = 41.77 years) who have previously undergone magnetic resonance imaging examinations. Information was obtained from the Dryad database. Univariate analysis, piecewise linear regression model, and multivariable logistic regression model were used for statistical analysis. A non-linear relationship was recognized between the cerebral WML volume and BD incidence, in which the inflection point of the WML volume was 6,200 mm³. The effect sizes and confidence intervals on the left and right sides of the emphasis point were 1.0009 (1.0003, 1.0015) and 0.9988 (0.9974, 1.0003), respectively. Subgroup analysis (WML volume < 6,200 mm³) showed that the cerebral WML volume (for 0.1 mm³ increase) was positively related to the BD incidence (OR = 1.11, 95% confidence interval [CI] (1.03, 1.21)). Here we show that the cerebral WML volume is positively and non-linearly correlated to the BD risk. Volumetric analysis of WML provide a better understanding of the association between WML and the BD risk, and thereby the pathophysiological mechanisms of BD.

Graphical abstract

A non-linear relationship between the volume of cerebral white matter lesions (WML) and bipolar disorder (BD) incidence is shown. The cerebral WML volume is positively and non-linearly correlated to the BD risk. The correlation is stronger when the cerebral WML volume was <6,200 mm³.Graphical AbstractA non-linear relationship between the volume of cerebral white matter lesions and bipolar disorder incidence is shown after adjusting for age; sex; lithium, atypical antipsychotic, antiepileptic, and antidepressant drug use; BMI; migraine; smoking; hypertension; diabetes mellitus; substance and alcohol dependency; and anxiety disorder.

Quantification of the Intrinsic T1 and T2 of Heschl's Gyri with MR Fingerprinting

PURPOSE

The human primary auditory cortex is located in the Heschl's gyrus (HG). To assess the intrinsic MR property in the gray matter of the HG (GM-HG) with T1 and T2 values using a commercially available MR fingerprinting (MRF) technique.

METHODS

The subjects were 10 healthy volunteers (with 20 HGs; mean age, 31.5 years old; range, 25-53 years old). Coronal T1 and T2 maps were obtained with commercially available MRF using a 3-Tesla MR system. Two radiologists measured the T1 and T2 values of the GM-HG, the GM in the superior temporal gyrus (GM-STG), and the GM in the middle temporal gyrus (GM-MTG) by drawing a ROI on coronal maps.

RESULTS

For both radiologists, the mean T1 and T2 values of the GM-HG were significantly lower than those in the GM-STG or GM-MTG (P < 0.01). The interobserver reliability using the intraclass correlation coefficients (ICC) (2,1) showed strong agreement for the measurement of the T1 and T2 values (ICCs =⃥ 0.80 and 0.78 for T1 and T2 values, respectively).

CONCLUSION

The T1 and T2 values on MRF for the GM-HG were lower than those for the GM-STG and GM-MTG, likely reflecting a higher myelin content and iron deposition in the GM-HG. Quantitative measurements using the MRF can clarify cortical properties with high reliability, which may indicate that MRF mapping provides new insights into the structure of the human cortical GM.

Localization of the central sulcus using the distinctive high signal intensity of the paracentral lobule on T1-weighted images

PURPOSE

The central sulcus is an important landmark in the brain. This study aimed to investigate the distinctive signal of the paracentral lobule (PL) on T1-weighted images (T1WIs; the white PL sign) and evaluate its usefulness as a new method of identifying the central sulcus.

METHODS

T1WIs of the brain of 96 participants (age, 58.9 ± 17.9 years; range, 8-87 years) scanned at 3-T MR system were retrospectively reviewed. First, we qualitatively analyzed the signal of the cortex of the PL by comparing it with that of the ipsilateral superior frontal gyrus on a 4-point grading score. Second, we compared the cortical signal intensity and gray/white-matter contrast between the PL and superior frontal gyrus. Third, we evaluated the usefulness of the PL signal for identifying the central sulcus.

RESULTS

The PL cortex was either mildly hyperintense (grade 2) or definitely hyperintense (grade 3) in comparison with that of superior frontal cortex in all participants. The signal intensity of the PL cortex was significantly higher than that of the superior frontal cortex (p < 0.001), whereas the gray/white-matter contrast of the PL was weaker than that of the superior frontal gyrus (p < 0.001). The central sulci were identified with 94.3% accuracy (181/192) using the new method.

CONCLUSION

The white PL sign may be helpful in identifying the central sulcus, and this approach can be recognized as a new method for identification of the central sulcus.

Reduced gray-white matter contrast localizes the motor cortex on double inversion recovery (DIR) 3T MRI

PURPOSE

Reduced gray-white matter contrast along the central sulcus has been described on T1- and T2-weighted magnetic resonance imaging (MRI). The purpose of this study was to assess the gray-white matter contrast of the motor cortex on double inversion recovery (DIR), a sequence with superior gray-white matter differentiation.

METHODS

The gray-white matter signal on DIR was retrospectively compared to T1-weighted magnetization-prepared rapid gradient echo (T1-MPRAGE) using normal (n = 25) and abnormal (n = 25) functional MRI (fMRI) exams. Quantitative gray-white matter contrast ratios (CR) of the precentral and adjacent gyri were obtained on normal exams. Two neuroradiologists qualitatively rated reduced gray-white matter contrast of the hemispheres of both normal and abnormal exams. Hand motor functional mapping was used as a reference.

RESULTS

In normal hemispheres (n = 50), the mean CR was significantly lower on DIR (0.44) vs T1-MPRAGE (0.63, p < 0.001). Reduced gray-white matter contrast was categorized as "definitely present" more frequently on DIR than T1-MPRAGE by reviewers in both normal (n = 50; reviewer 1 DIR 88% and MPRAGE 68%, p = 0.02; reviewer 2 DIR 86% and T1-MPRAGE 64%; p=0.01) and abnormal hemispheres (n = 50; reviewer 1 DIR 80% and T1-MPRAGE 38%, p < 0.001; reviewer 2 DIR 74% and T1-MPRAGE 46%, p = 0.005).

CONCLUSION

Reduced gray-white matter contrast of the motor cortex is more pronounced on DIR compared to T1-MPRAGE on quantitative and qualitative assessments of normal MRI exams. In abnormal cases, reviewers more definitively identified the motor cortex on DIR. In cases with distorted brain anatomy, DIR may be a useful adjunct sequence to localize the motor cortex.

Signal intensity of cerebral gyri in corticobasal syndrome on phase difference enhanced magnetic resonance images: Comparison of progressive supranuclear palsy and Parkinson's disease

We evaluated cerebral gyri (CG) on phase difference enhanced imaging (PADRE) of corticobasal syndrome (CBS), progressive supranuclear palsy (PSP), and Parkinson's disease (PD) patients to determine whether it is possible to discriminate among them on an individual basis. Two radiologists reviewed appearance of the normal CG and that of CBS patients on PADRE, and deviations from the appearance of the normal CG were recorded. Next, based on the CG abnormalities, two other reviewers reviewed PADRE images from 12 CBS, 14 PSP, and 30 PD patients. In healthy subjects on the PADRE images, the signal intensity (SI) of the gray matter (GM) was homogeneously, slightly hyperintense to the subcortical white matter (SCWM), and the SI of the SCWM was homogeneously hypointense. In CBS patients, hypointense layer in superficial GM and disappearance of hypointense in SCWM. The frequency of the abnormal findings on PADRE in the blinded manner by two readers was 100% (12/12), 3% (1/30), and 29% (4/14 in Reader 1) or 36% (5/14 in Reader 2) in CBS PD, and PSP patients, respectively. Laterality of the PADRE findings was showed in 12 (100%) CBS patients and 3 (21%) PSP, but not in any PD patients. The previously reported typical findings in CBS on conventional magnetic resonance image (MRIs) were observed in only 42% (5/12) of CBS patients. In conclusion, the abnormal findings in CG on PADRE appears more useful than conventional MRI findings for discriminating CBS from PD on an individual basis.

Facial nerve atrophy in patients with amyotrophic lateral sclerosis: Evaluation with fast imaging employing steady-state acquisition (FIESTA)

BACKGROUND

In amyotrophic lateral sclerosis (ALS), motor neurons in the brainstem markedly deplete, whereas sensory neurons are less severely affected.

PURPOSE

To determine whether facial nerve (FN) measurement on 3D fast imaging employing steady-state acquisition (FIESTA) is useful for ALS diagnosis.

STUDY TYPE

Retrospective.

SUBJECTS

Fifteen ALS patients and 16 controls.

FIELD STRENGTH/SEQUENCE

3T FIESTA MR.

ASSESSMENT

The cross-sectional area of the FN and cochlear nerve (CN) were measured, and the FN/CN ratio (FCR) was assessed. For qualitative assessment, the FN cross-sectional area was compared with that of the CN and the following scores were assigned: score 1 (large), the FN is larger than the CN; score 2 (almost equal), the size difference between the FN and CN is within 10%; score 3 (small), the FN is smaller than the CN (10-50%); score 4 (significantly small), size of the FN is less than half the size of the CN.

STATISTICAL TESTS

The differences in FCR between the ALS patients and the controls were tested using the Wilcoxon Mann-Whitney U-test. For the qualitative and quantitative assessments, we performed a receiver operating characteristic analysis for the diagnosis of ALS with an abnormal finding as score 3 or 4.

RESULTS

The mean FCR was significantly smaller for ALS patients (0.71 ± 0.17) than for controls (0.95 ± 0.08) (P < 0.001) and the area under the curve was 0.93. When an FN score was 3 or 4, indicative of FN atrophy, the sensitivity and specificity values of FIESTA for discriminating ALS patients from controls were 93.3% (14/15) and 90.0% (18/20), respectively.

DATA CONCLUSION

The FN atrophy revealed on FIESTA, which may reflect lower motor neuron impairment in ALS, allowed us to distinguish ALS patients from controls with a high degree of accuracy.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:757-766.

Signal intensity of peri-rolandic cortex identifies the central sulcus on double inversion recovery MRI

BACKGROUND

Identification of the central sulcus can require inspection of subtle differences or require certain pulse sequences. This study identifies the central sulcus by signal intensity on Double Inversion Recovery (DIR) images in multiple anatomic locations and imaging planes.

METHODS

49 patients (98 hemispheres) were retrospectively reviewed by three neuroradiologists and one radiology resident. The central sulcus was compared to the surrounding sulci for differences in signal intensity at axial hand knob, axial operculum, and lateral convexity sagittal images (294 locations) on DIR images. The use of the 'disappearing central sulcus sign' where the window level is increased at constant width and black/white inversion were also assessed.

RESULTS

In 49 patients (22 female, 27 male; median age 36 years), the central sulcus cortex signal intensity was lower than adjacent sulci with a frequency of 90/98 (91.8%) at the axial hand knob level, 68/98 (69.4%) at the axial operculum level, and 76/98 (77.5%) at the sagittal level. With black and white inversion, the frequencies were of 96/98 (98%), 92/98 (94%), and 87/98 (89%). The central sulcus was the first to disappear at all three levels with high degrees of inter-reader agreement (86%-99%). Traditional anatomic landmarks were absent or conflicting in seven hemispheres (5 patients). The central sulcus was identified by DIR signal intensity in all seven hemispheres.

CONCLUSIONS

The central sulcus can be identified by differences in signal intensity of the peri-rolandic cortex on DIR. Use of black/white inversion and the disappearing central sulcus sign may further facilitate identification.

Invisible cortex sign: A highly accurate feature to localize the inferolateral central sulcus

INTRODUCTION

The central sulcus is a key landmark on MRI of the brain, but its inferolateral portion is difficult to identify if unable to trace the sulcus superoinferiorly. The authors observed that the cortex abutting the central sulcus appears isointense to the adjacent white matter on DWI, we named this the 'invisible cortex sign' and our study evaluates whether it could be used to identify the inferolateral central sulcus.

METHODS

Observational study of 108 consecutive 'normal' MRI studies performed from May 2016 to January 2017. A single axial DWI image - obtained in the anterior commissure-posterior commissure plane - was selected from each scan just above the subcentral gyrus such that it included the most inferolateral portion of the central sulcus. These single images were given to 10 readers (neuroradiologists, a neuroradiology fellow and radiology trainees) who marked the central sulcus based on the presence of the 'invisible cortex sign'. Their accuracy in identifying the central sulcus was compared with that of the principal investigators, who used tri-planar T1 volumetric MRI sequences.

RESULTS

One hundred and eight consecutive patients (55 female, 53 male) were selected, ranging from 18 to 81 years old (mean = 40.5, σ = 18.2). The central sulcus was correctly identified in 95.5% of cases (σ = 3.7%; range 89.4-99.1%).

CONCLUSION

The 'invisible cortex sign' is a highly accurate method of identifying the inferolateral central sulcus on a single axial DWI slice without relying on the more superior aspects of the sulcus.

Motor cortex hypointensity on susceptibility-weighted imaging: a potential imaging marker of iron accumulation in patients with cognitive impairment

PURPOSE

To assess the prevalence and characteristics of motor cortex hypointensity on 3-T susceptibility-weighted imaging (SWI) in patients with cognitive impairment and examine its clinical significance.

METHODS

The institutional review board approved this retrospective study and waived the requirement for informed consent. A total of 127 patients with a clinical diagnosis of probable Alzheimer's disease (AD) (n = 32) or mild cognitive impairment (MCI) (n = 95) and 127 age- and sex-matched control subjects underwent 3-T brain magnetic resonance imaging. SWI was analyzed for both subjective visual scoring and the quantitative estimation of phase shift in the posterior bank of the motor cortex. A multivariate logistic regression analysis was performed to identify clinical and imaging variables associated with motor cortex hypointensity on SWI.

RESULTS

Motor cortex hypointensity on SWI was observed in 94/127 cognitively impaired patients (74.0%) and 72/127 control subjects (56.7%) (p = 0.004). Age was the only variable that was significantly associated with motor cortex hypointensity in patients with cognitive impairment (odds ratio, 1.15; 95% confidence interval, 1.065-1.242; p < 0.001). The quantitative analysis confirmed a significant increase in phase shifting in the posterior bank of the motor cortex in patients with positive motor cortex hypointensity on SWI (p < 0.001).

CONCLUSION

Motor cortex hypointensity on SWI was more frequently found in patients with cognitive impairment than in age-matched controls and was positively associated with age. Thus, it may be a potential imaging marker of iron accumulation in patients with MCI or AD.

The "White Gray Sign" Identifies the Central Sulcus on 3T High-Resolution T1-Weighted Images

BACKGROUND AND PURPOSE

The central sulcus is an important anatomic landmark, but most methods of identifying it rely on variable gyral and sulcal patterns. We describe and assess the accuracy of reduced gray-white contrast along the central sulcus, an observation we term the "white gray sign."

MATERIALS AND METHODS

We conducted a retrospective review of 51 fMRIs with a T1-weighted 3D inversion recovery fast-spoiled gradient-echo and concomitant hand-motor fMRI, which served as confirmation for the location of the central sulcus. To measure gray-white contrast across the central and adjacent sulci, we performed a quantitative analysis of 25 normal hemispheres along the anterior and posterior cortices and intervening white matter of the pre- and postcentral gyri. 3D inversion recovery fast-spoiled gradient-echo axial images from 51 fMRIs were then evaluated by 2 raters for the presence of the white gray sign as well as additional established signs of the central sulcus: the bracket, cortical thickness, omega, and T signs.

RESULTS

The mean gray-white contrast along the central sulcus was 0.218 anteriorly and 0.237 posteriorly, compared with 0.320 and 0.295 along the posterior precentral and anterior postcentral sulci, respectively (P < .001). Both raters correctly identified the central sulcus in all 35 normal and 16 abnormal hemispheres. The white gray sign had the highest agreement of all signs between raters and was rated as present the most often among all the signs.

CONCLUSIONS

Reduced gray-white contrast around the central sulcus is a reliable sign for identification of the central sulcus on 3D inversion recovery fast-spoiled gradient-echo images.

Signal intensity of superficial white matter on phase difference enhanced imaging as a landmark of the perirolandic cortex

Background The superficial white matter (SWM), which fills the space between the deep white matter and the cortex, has not been well characterized. Purpose To determine whether the assessment of the relative signal intensity (SI) of the SWM in the precentral and postcentral gyri on phase difference enhanced (PADRE) images contributes in establishing anatomical landmark. Material and Methods The study population consisted of 43 normal subjects (28 women, 15 men; mean age, 52.9 years; age range, 22-90 years). By the consensus of two observers, the precentral gyri, postcentral gyri, and superior frontal cortex (SFC) were identified based on the established anatomical methods. The SI of the SWM in the precentral and postcentral gyri on PADRE images was divided into three grades in comparison with that of the SFC: Grade I, isointense; Grade II, slightly hypointense; and Grade III, markedly hypointense. Results The SWM in the precentral and postcentral gyri showed hypointensity on PADRE images. In the SI analyses of the PADRE images, the Grade I, Grade II, and Grade III appearances were found in one (1%), 20 (23%), and 65 (76%) of the 86 precentral gyri (43 subjects), respectively, and in one (1%), 23 (27%), and 62 (72%) of the 86 postcentral gyri, respectively. Conclusion On PADRE images, the perirolandic SWM showed hypointensity compared to other cerebral cortices, which probably reflects differences in the concentrations of the nerve fibers, as well as the higher myelin content. PADRE may be useful for the identification of the central sulcus by assessing the SI of the SWM.

Zebra sign of precentral gyri in amyotrophic lateral sclerosis: A novel finding using phase difference enhanced (PADRE) imaging-initial results

OBJECTIVE

We compared the precentral gyri (PG) on the PADRE of patients with amyotrophic lateral sclerosis (ALS) and healthy subjects (HSs) in order to determine whether it is possible to discriminate between ALS patients and HSs on an individual basis.

METHODS

First, two radiologists reviewed the appearance of the normal PG and that of ALS patients on PADRE in a non-blinded manner, and deviations from the appearance of the normal PG were recorded. Next, based on the presence of PG abnormalities on PADRE, we performed an observer performance study using 16 ALS patients and 16 HSs.

RESULTS

The radiologists were able to consensually define the PG as abnormal on PADRE when a low-signal-intensity layer was observed in the gray matter of the PG; a three- or four-layer organization (zebra sign) was characterized by the low-signal-intensity layer. The observer performance study demonstrated that the sensitivity, specificity, and accuracy of PG abnormalities on PADRE for discriminating ALS patients from HSs were 94 %, 94 %, and 94 %, respectively, for reviewers 1 and 2.

CONCLUSIONS

It was possible to discriminate between ALS patients and HSs based on the presence of PG abnormalities on PADRE, which may reflect upper motor neuron impairment in ALS.

KEY POINTS

• PADRE reveals low-signal-intensity layer in the PG of ALS • By PADRE findings on PG, we can discriminate ALS from HSs • PADRE may be a useful method for detecting UMN impairment in ALS.

Pitfalls of 3D FLAIR brain imaging: a prospective comparison with 2D FLAIR

RATIONALE AND OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

Although 3D FLAIR may replace 2D FLAIR images for most patients, radiologists should keep in mind that 3D has some pitfalls.

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.

T₂* mapping and B₀ orientation-dependence at 7 T reveal cyto- and myeloarchitecture organization of the human cortex

Ultra-high field MRI (≥ 7 T) has recently shown great sensitivity to depict patterns of tissue microarchitecture. Moreover, recent studies have demonstrated a dependency between T₂* and orientation of white matter fibers with respect to the main magnetic field B₀. In this study we probed the potential of T₂* mapping at 7 T to provide new markers of cortical architecture. We acquired multi-echo measurements at 7 T and mapped T₂* over the entire cortex of eight healthy individuals using surface-based analysis. B₀ dependence was tested by computing the angle θ(z) between the normal of the surface and the direction of B₀, then fitting T₂*(θ(z)) using model from the literature. Average T₂* in the cortex was 32.20 +/- 1.35 ms. Patterns of lower T₂* were detected in the sensorimotor, visual and auditory cortices, likely reflecting higher myelin content. Significantly lower T₂* was detected in the left hemisphere of the auditory region (p<0.005), suggesting higher myelin content, in accordance with previous investigations. B₀ orientation dependence was detected in some areas of the cortex, the strongest being in the primary motor cortex (∆R₂*=4.10 Hz). This study demonstrates that quantitative T₂* measures at 7 T MRI can reveal patterns of cytoarchitectural organization of the human cortex in vivo and that B₀ orientation dependence can probe the coherency and orientation of gray matter fibers in the cortex, shedding light into the potential use of this type of contrast to characterize cyto-/myeloarchitecture and to understand the pathophysiology of diseases associated with changes in iron and/or myelin concentration.

Brain iron deposition and sequence characteristics in Parkinsonism: comparison of SWI, T₂* maps, T₂-weighted-, and FLAIR-SPACE

OBJECTIVES

To compare quantitatively T2- and T2*-based magnetic resonance imaging sequences in patients with symptoms of Parkinson disease and to evaluate the information content of those sequences regarding brain iron concentration.

MATERIALS AND METHODS

We imaged 51 patients with symptoms of Parkinson disease on 3-T magnetic resonance imaging with T2-weighted sampling perfection with application optimized contrasts using different flip-angle evolution (SPACE), fluid attenuation inversion recovery (FLAIR)-SPACE, susceptibility-weighted imaging (SWI), and parametric T2* sequence (MapIt). Signal analysis was performed in 22 regions of interest in the brain.

RESULTS

Correlations (r2 = 0.82...0.96) with brain iron concentration were excellent. Contrast and tissue separability ratios were best in the T2* maps and FLAIR-SPACE, respectively. Good correlations of contrast were reached between SWI and both T2-weighted SPACE and FLAIR-SPACE. Their relation to quantitative T2* values was reminiscent of a quadratic curve shape. However, separation into gray and white matter revealed a linear positive and negative correlation, respectively.

CONCLUSIONS

SWI showed potential in differentiating illnesses characterized by brain iron deposition. Closely similar information was given by T2-weighted SPACE and FLAIR-SPACE, whereas other sequence comparisons revealed dispersion from intersequence agreement.

Superficial siderosis associated with a chronic subdural hematoma: T2-weighted MR imaging at 3T

RATIONALE AND OBJECTIVES

The purposes of this study were to assess the association between superficial siderosis (SS) and subdural hematoma (SDH) and to evaluate the magnetic resonance imaging (MR) characteristics of SS in patients with the presence or histories of SDH compared to those with histories of aneurysmal subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

A radiology database for a 4-year period contained data on patients with diagnoses of SDH. From these patients, 47 patients were further selected who underwent brain MR examinations using a 3-T MR system (the SDH group). Using T2-weighted images, two neuroradiologists evaluated the presence or absence and the characteristics of SS findings by comparing the patients with histories of aneurysmal subarachnoid hemorrhage (the SAH group; n = 36). The SS findings were classified into three types: apical (SS at the top of the surface of the gyrus of the cerebral hemisphere), gyral (SS surrounding the gyrus), and mixed.

RESULTS

SS findings were seen in 13 patients (27.7%) in the SDH group (SS-SDH) and 13 patients (36.1%) in the SAH group (SS-SAH); all 13 cases of SS-SDH were the apical type, whereas the 13 cases of SS-SAH were either the gyral (n = 9 [69.2%]) or mixed (n = 4 [30.8%]) type. SS-SDH was seen only in the cerebral hemisphere ipsilateral to the side of the SDH (12 of 13 [92.3%]). All 13 cases of SS-SDH were accompanied by thinning of gray-matter intensity in the cerebral cortex, which was more frequently seen than in SS-SAH (P < .01).

CONCLUSION

SDH occasionally causes the SS-like MR findings, and the pathogenesis of SS-SDH may be also different from that of SS-SAH.