Mean Phase Values Research Articles

Electrical Impedance Myography in Dogs With Degenerative Myelopathy.

Canine degenerative myelopathy (DM) leads to disuse and neurogenic muscle atrophy. Currently there is a lack of non-invasive quantitative measures of muscle health in dogs with DM. Muscle pathology has been previously quantified in other disorders using the technique of electrical impedance myography (EIM) but it has not been reported for DM. The objective of this study was to compare EIM between DM-affected and similar aged healthy dogs as well as assess EIM changes over time in DM-affected dogs. Multifrequency EIM was performed on DM affected dogs at baseline and during disease progression and on age-matched healthy dogs. Muscles evaluated in the pelvic limbs included the craniotibialis, gastrocnemius, gracilis, sartorius, and biceps femoris. The 100 kHz phase angle was extracted from the full frequency set for analysis. Phase values were lower in DM dogs as compared to healthy controls. Specifically, phase of the gastrocnemius was lower on the left (θ = 7.69, 13.06; p =0.002) and right (θ= 6.11, 11.72; p = 0.001) in DM vs. control dogs, respectively. The mean phase value of all measured muscles was also lower on the left (θ = 9.24, 11.62; p = 0.012) and right (θ = 9.18, 11.72; p = 0.021). Other individual muscles measured did not reach statistical significance, although values were consistently lower in DM-affected dogs. With disease progression, downward trends in phase values were detected in DM-affected dogs when monitored serially over time. This study demonstrates that EIM 100 kHz phase values are sensitive to muscle pathology in DM and that phase values are decreased in dogs with DM. Measurements from the gastrocnemius muscle show the greatest differences from similar aged healthy dogs suggesting it may be the preferred muscle for future EIM studies.

Multimodal on-chip nanoscopy and quantitative phase imaging reveals the nanoscale morphology of liver sinusoidal endothelial cells

Visualization of three-dimensional (3D) morphological changes in the subcellular structures of a biological specimen is a major challenge in life science. Here, we present an integrated chip-based optical nanoscopy combined with quantitative phase microscopy (QPM) to obtain 3D morphology of liver sinusoidal endothelial cells (LSEC). LSEC have unique morphology with small nanopores (50-300 nm in diameter) in the plasma membrane, called fenestrations. The fenestrations are grouped in discrete clusters, which are around 100 to 200 nm thick. Thus, imaging and quantification of fenestrations and sieve plate thickness require resolution and sensitivity of sub-100 nm along both the lateral and the axial directions, respectively. In chip-based nanoscopy, the optical waveguides are used both for hosting and illuminating the sample. The fluorescence signal is captured by an upright microscope, which is converted into a Linnik-type interferometer to sequentially acquire both superresolved images and phase information of the sample. The multimodal microscope provided an estimate of the fenestration diameter of 119 ± 53 nm and average thickness of the sieve plates of 136.6 ± 42.4 nm, assuming the constant refractive index of cell membrane to be 1.38. Further, LSEC were treated with cytochalasin B to demonstrate the possibility of precise detection in the cell height. The mean phase value of the fenestrated area in normal and treated cells was found to be 161 ± 50 mrad and 109 ± 49 mrad, respectively. The proposed multimodal technique offers nanoscale visualization of both the lateral size and the thickness map, which would be of broader interest in the fields of cell biology and bioimaging.

Demyelination and remyelination detected in an alternative cuprizone mouse model of multiple sclerosis with 7.0\xa0T multiparameter magnetic resonance imaging

The aim of this study was to investigate the mechanisms underlying demyelination and remyelination with 7.0 T multiparameter magnetic resonance imaging (MRI) in an alternative cuprizone (CPZ) mouse model of multiple sclerosis (MS). Sixty mice were divided into six groups (n = 10, each), and these groups were imaged with 7.0 T multiparameter MRI and treated with an alternative CPZ administration schedule. T2-weighted imaging (T2WI), susceptibility-weighted imaging (SWI), and diffusion tensor imaging (DTI) were used to compare the splenium of the corpus callosum (sCC) among the groups. Prussian blue and Luxol fast blue staining were performed to assess pathology. The correlations of the mean grayscale value (mGSV) of the pathology results and the MRI metrics were analyzed to evaluate the multiparameter MRI results. One-way ANOVA and post hoc comparison showed that the normalized T2WI (T2-nor), fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) values were significantly different among the six groups, while the mean phase (Φ) value of SWI was not significantly different among the groups. Correlation analysis showed that the correlation between the T2-nor and mGSV was higher than that among the other values. The correlations among the FA, RD, MD, and mGSV remained instructive. In conclusion, ultrahigh-field multiparameter MRI can reflect the pathological changes associated with and the underlying mechanisms of demyelination and remyelination in MS after the successful establishment of an acute CPZ-induced model.

Temperature annual cycle variations and responses to surface solar radiation in China between 1960 and 2016

AbstractThe annual temperature cycle affects atmospheric circulation, biomass cycling, and human life. Its variation is influenced by surface solar radiation, which plays a key role in surface energy budgets. In this study, the Fourier transform method is used to analyse the spatial distribution and long‐term variations in temperature phase, amplitude, and baseline terms between 1960 and 2016 in China. Mean surface air temperature has a north–south gradient for phase, amplitude, and baseline. The regional mean phase values of the maximum, minimum, and mean temperatures in South China are larger than in North China, indicating that the timing of the annual cycle in Southern China is several days later than in Northern China. At the national scale, the annual maximum, minimum, and mean surface air temperature cycles are advancing, decreasing in range, and have a rising baseline. Linear regression is used to quantify the effect of surface solar radiation on temperature by removing its contribution on the raw maximum and mean temperatures. The surface solar radiation increases the phase of maximum and mean daily air temperatures, but reduces the amplitude and baseline. The surface solar radiation effect on maximum temperature is especially significant on the Yunnan‐Guizhou Plateau located in the south‐southwest. The phase of maximum temperature adjusted for solar radiation for the Plateau is similar to South China at the same latitude and later than the raw maximum temperature.

Longitudinal Study of Iron Deposition and Volume in the Precentral Gyrus in Patients with Relapse-Remitting Multiple Sclerosis

Objective: To longitudinally assess dynamic changes of iron deposition and volume of the precentral gyrus and its correlation with clinical manifestations of Relapse-Remitting Multiple Sclerosis(RRMS) by using 3D enhanced T2* weighted angiography(ESWAN). Methods: Thirty RRMS patients and thirty age- and sex-matched healthy controls were recruited and underwent ESWAN and 3D T1WI twice interval of one year with the same parameters. The mean phase values (MPVs) and volumes in precentral gyrus gray matter (PGM) were measured, and change of iron content and its correlation with volume, clinical manifestations were analyzed. Results: Compared with controls, the RRMS had higher iron deposition in both single-time measurements, but the volume decreased. Comparing to the first scan, we found significant difference in MPVs between the two times (P rs = 0.764, P rs = 0.592, P rs = 0.582, P rs = -0.399, P rs = -0.745, P rs = -0.367, P < 0.05). Conclusions: With the disease progression, the content of iron in PGM in RRMS patients is increasing, while the volume has no obvious change, suggesting that the iron deposition may precede or develop faster than cerebral atrophy.

Common-Mode Noise Suppression Technique in Interferometric Fiber-Optic Sensors

Efficient suppression of common-mode noises (CMNs) is significant for the performance of interferometric fiber-optic sensor system. To suppress CMNs, a reference interferometer is normally required as noise canceller. In this paper, we firstly report a detailed correlation analysis between the outputs of the sensing and reference interferometers. By using a band-limited noise decomposing method, we show that the correlation coefficient of the two interferometer outputs is a strong function over their mean phase difference, which appears as the limiting factor of the CMN suppression effect. Based on the analysis, we propose a novel CMN suppression technique by locking the mean phase value of the sensing interferometer using a reference interferometer with a 3 × 2 coupler. Experimental results show that our technique can increase the correlation coefficient between the outputs of sensing and reference interferometers by 6% (to 0.93) and reduce its standard deviation by $\sim$ 70% compared to traditional method. The CMNs suppression factor is measured as $-$ 8.49 dB in the frequency range from 300 Hz to 1 kHz, comparing to $\sim -$ 6 dB achieved by traditional method of simple subtraction. Our results set a new benchmark on the noise level of interferometric fiber-optic sensors.

Optic radiations are thinner and show signs of iron deposition in patients with long-standing remitting-relapsing multiple sclerosis: an enhanced T2*-weighted angiography imaging study

ObjectiveThis study aimed to investigate iron deposition and thickness and signal changes in optic radiation (OR) by enhanced T2*-weighted angiography imaging (ESWAN) in patients with relapsing-remitting multiple sclerosis (RRMS) with unilateral and bilateral lesions or no lesions.MethodsFifty-one RRMS patients (42 patients with a disease duration [DD] ≥ 2 years [group Mor], nine patients with a DD < 2 years [group Les]) and 51 healthy controls (group Con) underwent conventional magnetic resonance imaging (MRI) and ESWAN at 3.0 T. The mean phase value (MPV) of the OR was measured on the phase image, and thickness and signal changes of the OR were observed on the magnitude image.ResultsThe average MPVs for the OR were 1,981.55 ± 7.75 in group Mor, 1,998.45 ± 2.01 in group Les, and 2,000.48 ± 5.53 in group Con. In group Mor, 28 patients with bilateral OR lesions showed bilateral OR thinning with a heterogeneous signal, and 14 patients with unilateral OR lesions showed ipsilateral OR thinning with a heterogeneous signal. In the remaining nine patients without OR lesions and in group Con, the bilateral OR had a normal appearance. In the patients, a negative correlation was found between DD and OR thickness and a positive correlation was found between MPV and OR thickness.ConclusionsWe confirmed iron deposition in the OR in the RRMS patients, and the OR thickness was lower in the patients than in the controls.Key Points• Enhanced T2*-weighted magnetic resonance angiography (ESWAN) provides new insights into multiple sclerosis (MS).• Focal destruction of the optic radiation (OR) is detectable by ESWAN.• Iron deposition in OR can be measured on ESWAN phase image in MS patients.• OR thickness was lower in the patients than in the controls.• Iron deposition and thickness changes of the OR are associated with disease duration.

Correlation of iron deposition and change of gliocyte metabolism in the basal ganglia region evaluated using magnetic resonance imaging techniques: an in vivo study.

IntroductionWe assessed the correlation between iron deposition and the change of gliocyte metabolism in healthy subjects’ basal ganglia region, by using 3D-enhanced susceptibility weighted angiography (ESWAN) and proton magnetic resonance spectroscopy (1H-MRS).Material and methodsSeventy-seven healthy volunteers (39 female and 38 male subjects; age range: 24–82 years old) were enrolled in the experiment including ESWAN and proton MRS sequences, consent for which was provided by themselves or their guardians. For each subject, the mean phase value gained by ESWAN was used to evaluate the iron deposition; choline/creatine (Cho/Cr) and mI/Cr ratios gained by 1H-MRS were used to evaluate gliocyte metabolism in the basal ganglia region of both sides. The paired t test was used to test the difference between the two sides of the basal ganglia region. Linear regression was performed to evaluate the relation between mean phase value and age. Pearson's correlation coefficient was calculated to analyze the relationship between the result of ESWAN and 1H-MRS.ResultsThere was no difference between the two sides of the basal ganglia region in the mean phase value and Cho/Cr. But in mI/Cr the mean phase value of each nucleus in bilateral basal ganglia decreased with increasing age. There are 16 r-values between the mean phase value and Cho/Cr and mI/Cr in bilateral basal ganglia region. And each of all p-values is less than 0.001 (p < 0.001).ConclusionsIron deposition in the bilateral basal ganglia is associated with the change of gliocyte metabolism with increasing age. Iron deposition in each nucleus of the basal ganglia region changes with age.

An improved electrical impedance myography (EIM) tongue array for use in clinical trials

ObjectivesElectrical impedance myography (EIM) measurements of the tongue could provide valuable information about bulbar dysfunction in amyotrophic lateral sclerosis (ALS). A prototype tongue depressor EIM array produced gag reflexes. The objectives of this study were to determine the reliability, mean phase values, and tolerability of tongue EIM measurements using a smaller electrode array. MethodsTongue EIM measurements were performed in a total of 31 healthy individuals and four neuromuscular patients with lingual abnormalities. Reliability was assessed by calculating the intraclass correlation coefficient (ICC) and percent difference in addition to performing Bland–Altman analyses. Standard descriptive statistics, including results of a Mann–Whitney test, were also determined. ResultsAt the 50kHz frequency, the ICCs for intra- and inter-rater reliability were 0.76 with 5.17% difference and 0.78 with 5.34% difference respectively. The mean EIM phase values of healthy participants (11.61°±1.00°) and patients (9.87°±1.28°) were significantly different (p=0.0051). None of the participants experienced gag reflexes or discomfort. ConclusionsThe small tongue array provided good inter- and intra-rater reliability, could preliminarily distinguish between healthy and diseased muscle, and was well-tolerated. SignificanceBiomarker information about tongue health could be more comfortably obtained with a smaller EIM array.

Quantitative phase microscopy: automated background leveling techniques and smart temporal phase unwrapping.

In order for time-dynamic quantitative phase microscopy to yield meaningful data to scientists, raw phase measurements must be converted to sequential time series that are consistently phase unwrapped with minimal residual background shape. Beyond the initial phase unwrapping, additional steps must be taken to convert the phase to time-meaningful data sequences. This consists of two major operations both outlined in this paper and shown to operate robustly on biological datasets. An automated background leveling procedure is introduced that consistently removes background shape and minimizes mean background phase value fluctuations. By creating a background phase value that is stable over time, the phase values of features of interest can be examined as a function of time to draw biologically meaningful conclusions. Residual differences between sequential frames of data can be present due to inconsistent phase unwrapping, causing localized regions to have phase values at similar object locations inconsistently changed by large values between frames, not corresponding to physical changes in the sample being observed. This is overcome by introducing a new method, referred to as smart temporal unwrapping that temporally unwraps and filters the phase data such that small motion between frames is accounted for and phase data are unwrapped consistently between frames. The combination of these methods results in the creation of phase data that is stable over time by minimizing errors introduced within the processing of the raw data.

Susceptibility-Weighted Imaging Manifestations in the Brain of Wilson's Disease Patients.

PurposeIt is well known that patients with Wilson’s disease (WD) suffer copper metabolism disorder. However, recent studies point to an additional iron metabolism disorder in WD patients. The purpose of our study was to examine susceptibility-weighted imaging (SWI) manifestations of WD in the brains of WD patients.MethodsA total of 33 patients with WD and 18 normal controls underwent conventional MRI (Magnetic resonance imaging) and SWI. The phase values were measured on SWI-filtered phase images of the bilateral head of the caudate nuclei, globus pallidus, putamen, thalamus, substantia nigra, and red nucleus. Student’s t-tests were used to compare the phase values between WD groups and normal controls.ResultsThe mean phase values for the bilateral head of the caudate nuclei, globus pallidus, putamen, thalamus, substantia nigra, and red nucleus were significantly lower than those in the control group (P < 0.001), and bilateral putamen was most strongly affected.ConclusionsThere is paramagnetic mineralization deposition in brain gray nuclei of WD patients and SWI is an effective method to evaluate these structures.

Iron deposition in the gray matter in patients with relapse-remitting multiple sclerosis: A longitudinal study using three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN)

PurposeTo investigate the relationship between the iron content by magnetic resonance imaging (MRI) and clinic correlation in patients with relapse-remitting multiple sclerosis (RRMS) over a two-year period. MethodsThirty RRMS patients and 30 healthy control subjects were examined twice, two years apart, by undergoing brain conventional MRI and three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN) sequences at 3.0T. Quantitative differences in iron content in deep gray matter (GM) nuclei and precentral gyrus GM between patients and control subjects with repeated-measures the mean phase values (MPVs) for ESWAN-filtered phase images. Spearman's rank correlation coefficient analysis was used to evaluate correlations of the MPVs, both 2-year-difference and single-time measurements, to disease duration, expanded disability status scale (EDSS) and times of recurrence. ResultsThe RRMS patients had higher GM iron concentration than that of the healthy control subjects in both single-time measurements, but only the substantia nigra (SN), and the precentral gyrus GM (PGM) showed a significant statistical difference (p<0.05). Using the paired samples t test, we found that there were significant differences in two-year-difference measurements of the MPVs in the putamen (PUT), the globus pallidus (GP), the head of the caudate nucleus (HCN), the thalamus (THA), SN, the red nucleus (RN), the dentate nucleus (DN) and PGM, especially in SN (t=2.92, p=0.007) in RRMS patients. The MPVs of the PUT, GP, HCN, THA, SN, RN, DN and PGM for the subgroup with RRMS patients in times of recurrence less than twice were similar to the healthy controls. There was no significant difference in all regions of interests (ROIs). However, there were significant differences in all ROIs except THA and GP for the other subgroup with RRMS patients in times of recurrence more than and equal to twice. Spearman's rank correlation coefficient analysis showed there were significant negative correlations between disease duration and the MPVs in the HCN (r=−0.516, p=0.004), DN (r=−0.468, p=0.009) and PGM (r=−0.84, p=0). However, no correlations were found between the EDSS scores and the MPVs. ConclusionsIron content in the GM can be measurable using MRI and our results confirmed that iron concentration was increasing in the GM of MS patients during two-year period compared to healthy controls. Furthermore, this study had also shown significant and substantial correlation of iron concentration with disease severity.

Preparing arbitrary pure states of spatial qudits with a single phase-only spatial light modulator

We present a new method for preparing multidimensional spatial qudits by means of a single phase-only spatial light modulator (SLM). This method improves previous ones that use two SLMs, one working in amplitude regime and the other in phase regime. To that end, we addressed diffraction gratings on the slits that define the state and then we performed a spatial filtering in the Fourier plane. The amplitude of the coefficients of the quantum state are determined by the modulation deep of the diffraction gratings, and the relative phase is the mean phase value of the diffraction gratings. This encoding result to be more compact, less expensive and use the photons more efficiently.

VALIDATION OF HIPPOCAMPAL TEXTURE FOR EARLY ALZHEIMER'S DISEASE DETECTION: GENERALIZATION TO INDEPENDENT COHORTS AND EXTRAPOLATION TO VERY EARLY SIGNS OF DEMENTIA

neurofibrillary tangles than LOAD patients. However, these findings have not been substantiated in clinical studies. Studies using Positron Emission Tomography (PET) with carbon-11-labelled Pittsburgh compound-B (PiB) were not conclusive in replicating the post-mortem findings. A previous study suggested that iron accumulation, which may reveal AD pathology and more specifically amyloid deposition, is reflected by phase information from 7T T 2*-weighted MRI sequences. The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of AD pathology, between EOAD and LOAD patients using 7T MR phase images. Methods: 12 EOAD patients, 17 LOAD patients and 17 healthy elderly controls (table 1) were scanned at 7T using a 2D transverse T 2*-weighted scan with a total imaging duration of 10 minutes. MRI scans were analyzed quantitatively by measuring lobar peak-to-peak phase shifts in the frontal, parietal, and left and right temporoparietal regions. Cortical parcellation was performed on the T 2*-weighted images using the segmented cortex and an anatomical atlas (AAL atlas) (figure 1). The regional mean gray matter (GM)/ white matter (WM) contrast was computed as the difference between the mean phase value of the GM and WM ROIs. Results: An increased peak-to-peak phase shift was found for all lobar regions in EOAD patients compared with LOAD patients (p1⁄40.05) (table 2). Regional mean phase contrast in EOAD patients was higher than in LOAD patients in the superior medial and middle frontal gyrus, anterior and middle cingulate gyrus, postcentral gyrus, superior and inferior parietal gyrus, and precuneus (p<0.042) (table 3). Conclusions: These data suggest that EOAD patients have an increased iron accumulation, as compared with LOAD patients, in specific cortical regions, which could also be related to increased amyloid deposition.

Relationship between the Phase Value of ESWAN and Fractional Anisotropy of Diffusion Tensor Imaging in Patients with Cerebral Microbleeds: Preliminary Results

Aims: The purpose of the present study was to measure phase values (PVs) and fractional anisotropy (FA) of cerebral microbleeds (CMBs) using phase and FA map, and to investigate the potential relationship between PVs and FAs in CMBs in vivo. Methods: We retrospectively analyzed 30 patients with CMBs using enhanced T2*-weighted angiography and diffusion tensor imaging. The PVs and FAs of CMBs were measured and documented, and the mean FAs were compared between CMBs and the corresponding normal brain tissue. The mean PVs were correlated with FAs in CMBs in seven different brain regions. Results: A total of 106 CMBs were defined, and the mean FA of the CMBs in white matter, EC/IC/CR, thalamus, and cerebellum were significantly lower than that of normal brain tissue in the control group (p < 0.05). Positive correlations were observed between the PV and FA of CMBs in white matter, external capsule, internal capsule and corona radiata (r = 0.70, 0.38). Conclusion: Enhanced T2*-weighted angiography and diffusion tensor imaging sequence may be useful neuroimaging sequences that could reflect the severity of damage of white matter by measuring the FA of CMBs and provide useful reference data for the quantitative assessment of CMBs.

Quantitative assessment of iron deposition in the midbrain using 3D-enhanced T2 star weighted angiography (ESWAN): A preliminary cross-sectional study of 20 Parkinson’s disease patients

Conventional magnetic resonance imaging (MRI) assesses neurodegenerative structural changes in the cerebral anatomy of Parkinson's disease (PD) patients but cannot detect non-structural abnormalities; however, enhanced T2 star weighted angiography (ESWAN) can precisely indicate PD-related substantia nigra (SN) iron deposition. The differences in ESWAN-based parameters between different PD stages were assessed using midbrain iron deposits of 20 PD patients aged 64.3±12.7 (41–85) years grouped by Hoehn and Yahr staging into minimal (stages ≤2.5) or moderate to severe (stages ≥3.0) motor impairment groups and 14 healthy control subjects. Conventional MRI and ESWAN measurements of mean phase value (MPV) and midbrain dimensions (width and diameter) revealed similar anatomical characteristics; however, ESWAN revealed the presence of smaller MPVs and SN pars compacta (SNc) (P<0.01) and a negative correlation between reduction extent and motor impairment (P<0.01). SNc width to midbrain diameter was reduced in moderate to severe impairment patients versus control and minimal impairment patients (both P<0.01). A positive correlation was found between MPV and width or SNc width to midbrain diameter ratio (P<0.01 and P<0.05, respectively). Minimal impairment group mean MPV and substantia nigra pars reticulata (SNr) width evidenced no significant reduction, unlike significant reductions in the moderate to severe impairment group (P<0.01). No significant changes were observed in MPV or width in the RN region (P>0.05). ESWAN allows for early and accurate iron deposition determination in PD patients, particularly useful as a supplement to conventional MRI in early-stage PD patients.

Effect of Age on MRI Phase Behavior in the Subcortical Deep Gray Matter of Healthy Individuals

It has been demonstrated that increased levels of iron in the brain occur with aging. In this study we investigated the nature of the association between age and SWI-filtered phase values, indicative of iron content, in the subcortical deep gray matter of healthy individuals. A total of 210 healthy individuals (men: n = 89, women: n = 121), mean age, 39.8 years (standard deviation = 15.5; range = 6-76 years), were imaged on a 3T scanner. Mean MRI phase, mean phase of low-phase voxels, and normalized volumes were determined for total subcortical deep gray matter, caudate, putamen, globus pallidus, thalamus, pulvinar nucleus, hippocampus, amygdala, nucleus accumbens, red nucleus, and substantia nigra. Linear and nonlinear regression models were used to explore the relationship between phase and volume measures, and aging. Mean phase values of subcortical deep gray matter structures showed a quadratic relationship, with individuals in late middle age (40-59 years) having the lowest mean phase values, followed by a reversal of this trend in the elderly. In contrast, mean phase of low-phase voxel measurements showed strong negative linear relationships with aging. Significantly lower phase values were detected in women compared with men (P < .001), whereas no sex differences were observed for mean phase of low-phase voxels. Normalized volume measurements were also linearly related to aging, and women showed smaller normalized volumes of subcortical deep gray matter structures than men (P < .001). Lower mean phase of low-phase voxels was related to decreased volume measures. A strong association between phase (quadratic effect; phase decreases are followed by increases), mean phase of low-phase voxels (linear effect), volume (linear effect), and age was observed. Low phase was related to brain atrophy.

Quantification of Phase Values of Cerebral Microbleeds in Hypertensive Patients Using ESWAN MRI

The presence of cerebral microbleeds (CMBs) may have predictive and diagnostic value for cerebrovascular diseases. The purpose of our study was to measure the phase values (PVs) of CMBs by phase maps. We retrospectively analyzed 75 patients with hypertension who had CMBs using enhanced T2*-weighted angiography (ESWAN). The PVs of CMBs were measured and documented. The mean PVs of CMBs were correlated with demographic features and the grade of white matter lesions for seven brain regions. A total of 275 CMBs were found. Their mean PV was - 1.39 ± 0.29 radians. The mean PV of CMBs in seven brain regions was significantly lower than that of red nucleus and substantia nigra of healthy controls (P < .05). The mean PV of CMBs in the basal ganglia gray matter was significantly lower than that of the brainstem, subcortical white matter, and cerebellum (P < 0.05). In subcortical white matter, the PVs were significantly lower in patients with hypertension < 10 years than for those patients with hypertension ≥ 10 years (P < 0.05). In basal ganglia gray matter, the PVs were significantly lower in men than in women (P < 0.05). There was no significant correlation between the PVs of CMBs and the demographic features addressed or the grade of white matter lesions. Measurement of the PV of phase maps using ESWAN sequence provides quantitative information for detection of CMBs. The measurement data reported herein will provide a reference for a longitudinal study of CMBs in the future.

Iron deposition in the precentral grey matter in patients with multiple sclerosis: A quantitative study using susceptibility-weighted imaging

PurposeSeveral studies suggest that iron deposition may play a role in multiple sclerosis (MS) pathology. Three-dimensional (3D) enhanced T2*-weighted angiography (ESWAN) at 3T was used to quantify iron deposition in the precentral grey matter in MS and its relationship with disease duration, atrophy and Expanded Disability Status Scale (EDSS) scores. MethodsWe recruited 33 patients with diagnosis of clinically definite MS and 31 age- and sex-matched healthy controls who underwent conventional brain MRI, 3D-ESWAN and 3D T1sequences. We obtained the mean phase values (MPVs) of the precentral grey matter on ESWAN-filtered phase images and volume of the precentral gyrus on 3D T1 images. We investigated the correlation between precentral grey matter MPVs, precentral gyrus volume, disease duration and EDSS scores of MS patients and healthy controls. ResultsThe precentral grey matter MPVs in MS patients and controls were 1870.83±56.61 and 1899.22±51.73 respectively and had significant difference in the MS group vs. the control group (t=−2.09, P=0.04). There was significant negative correlation between precentral grey matter MPVs and disease duration (r=−0.365, P=0.03). No correlation was found between MPVs and EDSS scores. Mean precentral gyrus volume in MS patients was 4368.55±867.78 whereas in controls was 5701.00±1184.03 with significant difference between volume of the precentral gyrus in MS patients compared to healthy controls (t=−5.167, P<0.001). There was a positive correlation between MPVs and precentral gyrus volume (r=0.291, P=0.020). ConclusionsOur study demonstrated that quantitative assessment of abnormal iron deposition in the precentral grey matter in MS patients can be measured using 3D-ESWAN.

Iron deposition of the deep grey matter in patients with multiple sclerosis and neuromyelitis optica: A control quantitative study by 3D-enhanced susceptibility-weighted angiography (ESWAN)

Previous studies have detected abnormal iron deposition in the deep grey matter (DGM) of multiple sclerosis (MS). The regional specificity of the DGM iron deposition in neuromyelitis optica (NMO) is still unclear. We compared the differences in the DGM iron concentration between MS and NMO patients. We enrolled 42 relapsing-remitting MS (RRMS) patients, 42 NMO patients and 42 healthy controls undergoing brain conventional MRI and three-dimensional (3D)-enhanced T(2)*-weighted angiography (ESWAN) sequences. We obtained the mean phase values (MPVs) for ESWAN-filtered phase images. An analysis of covariance (ANCOVA) was used to compare MPVs among three groups. The correlations of MPVs changes with disease duration and expanded disability status scale (EDSS) were analyzed. The RRMS patients had higher DGM iron concentration than did the NMO and control groups, but only the bilateral substantia nigra (SN) showed a significant statistical difference among three groups (p<0.05). In the RRMS group, the iron concentration in the bilateral head of the caudate nucleus (HCN) (left: p<0.0001; right: p=0.0134) and the dentate nucleus (DN) (p<0.05 for both) were correlated with disease duration. In the NMO group, no correlation was found between the DGM iron concentration and disease duration (p>0.05). Furthermore, no correlations were found between the DGM iron concentration and EDSS (p>0.05). We confirm the iron concentration in the DGM iron content of MS patients is more than NMO patients and healthy controls in the same age range. Furthermore, the disease duration was found to be a significant contributor to patients with MS.