Background
Adipose tissue is closely related to bone mass, bone quality, and bone fractures, but the connection between fat and bone is complex and gender‐related. Fat–water magnetic resonance ...imaging (MRI) and MR spectroscopy (MRS) are very useful tools for identifying tissue fat.
Purpose
To assess gender interactions between bone mineral density (BMD), bone marrow fat, and body mass index (BMI) in the elderly using fat–water MRI and MRS.
Study Type
Prospective/cohort.
Population
Sixty‐six women and 38 men (mean age, 62.3 years; range, 50–75 years), Asian.
Field Strength
A 1.5T MR equipped with a body and spine array coil. STEAM MRS and T2* Dixon were performed.
Assessment
Vertebral bone marrow fat ratio (MFR), BMI, and BMD were measured. Correlations between these variables and differences in bone density in MFR were assessed between participants, divided into three groups based on bone density.
Statistical Tests
Multiple regression; Pearson tests; analysis of covariance; analysis of variance.
Results
Multiple regression analysis identified gender, vertebral bone MFR, and BMI as significant predictors of vertebral BMD (P < 0.001). Among the women, vertebral BMD was negatively correlated with vertebral MFR (P = 0.011), but among the men, it was positively correlated with BMI (P = 0.048), although this relationship was confounded by age and MFR. Moreover, vertebral bone marrow fat and BMI were indeed statistically uncorrelated in the elderly (P = 0.357 in women; P = 0.961 in men).
Data Conclusion
We found gender interactions between fat and bone in the elderly. Higher bone marrow fat was correlated with lower trabecular BMD in older women but not in men. On the other hand, the positive correlation between BMI and BMD was more pronounced in men than in women.
Level of Evidence: 2
Technical Efficacy Stage: 2
J. Magn. Reson. Imaging 2020;51:1382–1389.
Abstract Systemic lupus erythematosus (SLE) is an autoimmune disease frequently associated with neuropsychiatric manifestations. No follow-up case report has characterized white matter alterations in ...patients with neuropsychiatric lupus erythematosus (NPSLE) before and after treatment. In this study, a 16-year-old NPSLE patient with severe neuropsychological symptoms was treated with steroid pulse therapy, and was scanned with conventional magnetic resonance (MR) and diffusion tensor imaging (DTI) at onset and 17 months after treatment. Conventional MR images showed diffuse brain atrophy and focal vasogenic edema in the putamen, but they did not reveal abnormalities in the corpus callosum. Region-of-interest analysis of DTI images showed that fractional anisotropy and fiber tracts increased significantly, while axial diffusivity, radial, and mean diffusivity decreased significantly in the corpus callosum after treatment. The results indicated that the vasogenic edema was present in the corpus callosum at onset and was significantly reduced after treatment. These changes were generally compatible with the patient’s clinical manifestations. Hence, we concluded that MR-DTI and fiber tractography are helpful to reveal the relationship between white matter alterations and neurological dysfunctions in NPSLE patients.
Background Absence seizures are a subtype of epileptic seizures clinically characterized by transient alterations in states of consciousness and by electroencephalography indicating diffuse ...spike-wave discharges (SWD). Conventional brain magnetic resonance imaging (MRI) is not routinely used to establish the diagnosis, but rather to rule out other diseases. The present study investigated tissue integrity in children with SWD epilepsy using diffusion tensor imaging (DTI). Methods Magnetic resonance imaging (MRI)-DTI was conducted in 18 patients with absence seizures and 10 control participants. Brain areas were evaluated using diffusion maps, and fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ||), and perpendicular diffusivity (λ⊥) values were extracted and analyzed. Tractography at the regions of abnormal diffusion indices was then reconstructed in each group, and tract symmetry was evaluated by an index of asymmetry (AI). Statistical analyses were performed using nonparametric Mann–Whitney U tests, with p values < 0.05 indicating statistical significance. Results Compared to the control group, patients with SWD epilepsy had lower FA values and higher MD values at the genu of the corpus callosum. There was also a stronger negative correlation between MD and FA values at the genu of the corpus callosum in patients than in control participants. The AI for the fiber tracts through the genu of the corpus callosum in the SWD group was significantly higher than that of the control group, indicating that tract distribution was more asymmetric in patients with epilepsy. There were no significant differences between groups in diffusion indices for other brain areas. Conclusion We observed microstructural changes in the genu of the corpus callosum, as well as reduced FA values, increased λ⊥ values, increased MD values, and asymmetric distribution of fiber tracts, indicating that DTI is more sensitive than conventional MRI to detect brain abnormalities in children with absence seizures.
Radiosensitivity in the breasts increases the risk of carcinogenesis from exposure to the ionizing radiation of computed tomography (CT) administered in the course of medical attention. Bismuth ...shielding techniques have been used to reduce radiation, but image noise increased, degrading image quality.
The aim of this study was to investigate how the use of iterative reconstruction (IR) combined with bismuth shielding influences image quality.
Women aged at least 20 years with body mass indexes <28 were recruited and randomly assigned to 1 of 3 CT scanning protocols without shielding, with a bismuth breast shield before the scout view, or with a bismuth breast shield after the scout view. All obtained images were reconstructed using an IR algorithm. To evaluate radiation dose, 2 Gafchromic films were placed over the clothes, 1 near each nipple.
Average dose reduction was significant (27.99%, P < .05) when bismuth shielding was applied after the scout view. Using the contrast-to-noise ratio, the image quality was found to be superior when the IR algorithm was applied. Using quantitative evaluations by 2 radiologists applying a 4-point Likert scale, significant differences in image quality were not found among the 3 protocols.
Bismuth breast shields, particularly when used after acquiring scout images, are effective at reducing radiation dose without undermining the diagnostic value of the images when the IR technique is applied.
Patients with neuropsychiatric systemic lupus erythematosus (NPSLE) may exhibit corpus callosal atrophy and tissue alterations. Measuring the callosal volume and tissue integrity using diffusion ...tensor imaging (DTI) could help to differentiate patients with NPSLE from patients without NPSLE. Hence, this study aimed to use an automatic cell-competition algorithm to segment the corpus callosum and to investigate the effects of central nervous system (CNS) involvement on the callosal volume and tissue integrity in patients with SLE.
Twenty-two SLE patients with (N = 10, NPSLE) and without (N = 12, non-NPSLE) CNS involvement and 22 control subjects were enrolled in this study. For volumetric measurement, a cell-competition algorithm was used to automatically delineate corpus callosal boundaries based on a midsagittal fractional anisotropy (FA) map. After obtaining corpus callosal boundaries for all subjects, the volume, FA, and mean diffusivity (MD) of the corpus callosum were calculated. A post hoc Tamhane's T2 analysis was performed to statistically compare differences among NPSLE, non-NPSLE, and control subjects. A receiver operating characteristic curve analysis was also performed to compare the performance of the volume, FA, and MD of the corpus callosum in differentiating NPSLE from other subjects.
Patients with NPSLE had significant decreases in volume and FA but an increase in MD in the corpus callosum compared with control subjects, whereas no significant difference was noted between patients without NPSLE and control subjects. The FA was found to have better performance in differentiating NPSLE from other subjects.
A cell-competition algorithm could be used to automatically evaluate callosal atrophy and tissue alterations. Assessments of the corpus callosal volume and tissue integrity helped to demonstrate the effects of CNS involvement in patients with SLE.
The size and shape of corpus callosum are important indicators for assisting diagnosis of many neurological diseases involving morphological changes of corpus callosum. A new automatic segmentation ...approach was proposed in this paper for boundary delineation of corpus callosum. The basic idea of the proposed approach was to perform segmentation on the red component of color-coded map of diffusion tensor magnetic resonance image (MR-DTI). The boundary of corpus callosum was delineated in two phases. Firstly, a rough boundary surrounding corpus callosum was derived by using a built-in contour function in Matlab. Then, this cell competition algorithm was applied to the area inside the rough boundary derived in the first phase. The proposed segmentation approach has been evaluated and compared to the Chan and Vese level set method by using the MR-DTI images of a healthy volunteer and a systemic lupus erythematorsus (SLE) patient. The implementation results showed that the proposed approach could delineate the boundaries of corpus callosum reasonably well for both cases, whereas the Chan and Vese level set method failed to catch the weak edge for the SLE patient.
碩士
國立臺灣大學
醫學工程學研究所
93
Recently, the technique of Diffusion Magnetic Resonance Imaging (Diffusion MRI) has developed to make progress in explaining perpetual controversy about neuroscience in human ...brain. Diffusion Tensor magnetic resonance Imaging (DTI) has been recognized as an important tool to reveal the axonal fiber tracts in cerebral white matter noninvasively in the clinical diagnosis image. By probing the translational displacement of water molecules, it provides the primary direction of water molecular diffusion which is correlated to the main pathway of fiber bundles. The eigenvector of the diffusion tensor at each location in the cerebral white matter represents the fiber orientation at the same location. Based on this information, 3D reconstruction and visualization of white matter fiber pathways can be produced by tractography.
The last, MR-DTI has achieved a reasonable cognition and judgement, making a difference from the past acquisition strategies for complicated structure of white matter bundl
The effect of tamoxifen on Ca(2+) signaling and viability in Madin Darby canine kidney (MDCK) cells was investigated by using fura-2 as a Ca(2+) probe. Tamoxifen evoked a rise in cytosolic free ...Ca(2+) levels (Ca(2+)(i)) concentration-dependently between 1 and 50 microM with an EC50 of 10 microM. The response was decreased by extracellular Ca(2+) removal. In Ca(2+)-free medium, pretreatment with 5 microM tamoxifen abolished the Ca(2+)(i) increase induced by the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (1 microM), but pretreatment with brefeldin A (50 microM; a Ca(2+) mobilizer of the Golgi complex), thapsigargin (an inhibitor of the endoplasmic reticulum Ca(2+) pump), and carbonylcyanide m-chlorophenylhydrazone (CCCP; a mitochondrial uncoupler), only partly inhibited tamoxifen-induced Ca(2+)(i) increases. This suggests that tamoxifen released Ca(2+) from multiple pools. Addition of 3 mM Ca(2+) induced a Ca(2+)(i) rise after pretreatment with 5 microM tamoxifen in Ca(2+)-free medium. Inhibiting inositol 1,4,5-trisphosphate formation with the phospholipase C inhibitor U73122 (2 microM) did not alter 5 microM tamoxifen-induced Ca(2+) release. The Ca(2+)(i) increase induced by 5 microM tamoxifen was not altered by La(3+), nifedipine, verapamil, or diltiazem. Tamoxifen (1-10 microM) decreased cell viability in a concentration- and time-dependent manner. Tamoxifen (5 microM) also increased Ca(2+)(i) in neutrophils, bladder cancer cells, and prostate cancer cells from humans and glioma cells from rats. Collectively, it was found that tamoxifen increased Ca(2+)(i) in MDCK cells by releasing Ca(2+) from multiple Ca(2+) stores in a manner independent of the production of inositol 1,4, 5-trisphosphate and also by triggering Ca(2+) influx from extracellular space. The Ca(2+)(i) increase was accompanied by cytotoxicity.
The effect of tamoxifen on Ca2+ signaling and viability in Madin Darby canine kidney (MDCK) cells was investigated by using fura-2 as a Ca2+ probe. Tamoxifen evoked a rise in cytosolic free Ca2+ ...levels (Ca2+i) concentration-dependently between 1 and 50 μM with an EC50 of 10 μM. The response was decreased by extracellular Ca2+ removal. In Ca2+-free medium, pretreatment with 5 μM tamoxifen abolished the Ca2+i increase induced by the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (1 μM), but pretreatment with brefeldin A (50 μM; a Ca2+ mobilizer of the Golgi complex), thapsigargin (an inhibitor of the endoplasmic reticulum Ca2+ pump), and carbonylcyanide m-chlorophenylhydrazone (CCCP; a mitochondrial uncoupler), only partly inhibited tamoxifen-induced Ca2+i increases. This suggests that tamoxifen released Ca2+ from multiple pools. Addition of 3 mM Ca2+ induced a Ca2+i rise after pretreatment with 5 μM tamoxifen in Ca2+-free medium. Inhibiting inositol 1,4,5-trisphosphate formation with the phospholipase C inhibitor U73122 (2 μM) did not alter 5 μM tamoxifen-induced Ca2+ release. The Ca2+i increase induced by 5 μM tamoxifen was not altered by La3+, nifedipine, verapamil, or diltiazem. Tamoxifen (1–10 μM) decreased cell viability in a concentration- and time-dependent manner. Tamoxifen (5 μM) also increased Ca2+i in neutrophils, bladder cancer cells, and prostate cancer cells from humans and glioma cells from rats. Collectively, it was found that tamoxifen increased Ca2+i in MDCK cells by releasing Ca2+ from multiple Ca2+ stores in a manner independent of the production of inositol 1,4,5-trisphosphate and also by triggering Ca2+ influx from extracellular space. The Ca2+i increase was accompanied by cytotoxicity.
PDF
