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Purpose

The aim of this study was to present a tractography algorithm using a two-tensor unscented Kalman filter (UKF) to improve the modeling of the corticospinal tract (CST) by tracking through regions of peritumoral edema and crossing fibers.

Methods

Ten patients with brain tumors in the vicinity of motor cortex and evidence of significant peritumoral edema were retrospectively selected for the study. All patients underwent 3-T magnetic resonance imaging (MRI) including functional MRI (fMRI) and a diffusion-weighted data set with 31 directions. Fiber tracking was performed using both single-tensor streamline and two-tensor UKF tractography methods. A two-region-of-interest approach was used to delineate the CST. Results from the two tractography methods were compared visually and quantitatively. fMRI was applied to identify the functional fiber tracts.

Results

Single-tensor streamline tractography underestimated the extent of tracts running through the edematous areas and could only track the medial projections of the CST. In contrast, two-tensor UKF tractography tracked fanning projections of the CST despite peritumoral edema and crossing fibers. Based on visual inspection, the two-tensor UKF tractography delineated tracts that were closer to motor fMRI activations, and it was apparently more sensitive than single-tensor streamline tractography to define the tracts directed to the motor sites. The volume of the CST was significantly larger on two-tensor UKF than on single-tensor streamline tractography (\(p < 0.001\)).

Conclusion

Two-tensor UKF tractography tracks a larger volume CST than single-tensor streamline tractography in the setting of peritumoral edema and crossing fibers in brain tumor patients.
  相似文献   
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Objective: The co-occurrence of sleep problems, cognitive impairment, and depression among the elderly suggests that these three conditions are likely to be interrelated. Recent findings suggest that depressive symptoms moderate the relationship between sleep problems and cognitive impairment in elderly people but methodological problems have led to inconsistent conclusions. The present study aims to better understand the relationship between sleep quality, depressive symptoms, and cognitive function. Method: We administered the Repeatable Battery for the Assessment of Neuropsychological Status and self-report measures of sleep quality and depression to 380 elderly participants (Mage = 68 years, SD= 5.7). Bootstrapped moderation analyses were conducted to examine the role of depressive symptoms in the relationship between sleep and various aspects of cognitive function. Results: This moderation effect was significant in the domains of delayed memory (ΔR2 = .01, F = 4.5, p = .04), language (ΔR2 = .01, F = 4.6, p = .035), and general cognitive status (ΔR2 = .01, F = 5.3, p = .02). However, unlike previous studies, higher sleep quality corresponded to better outcomes in delayed memory, language abilities, and general cognitive status in participants with low levels of depressive symptoms. No significant relationship between sleep quality and any cognitive function was observed among participants with high levels of depressive symptoms. Conclusions: Among individuals who reported low levels of depressive symptoms, sleep quality was positively related to cognitive performance in the domains of delayed recall, language, and general cognitive status. However, sleep quality was not significantly associated with cognitive abilities in these domains among participants with elevated levels of depressive symptoms; participants had relatively poor outcomes in these cognitive domains regardless of their sleep quality.  相似文献   
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International Urology and Nephrology - In the original publication, the second author’s affiliation was incorrectly published as “Department of Physiology, RAK College of Medical...  相似文献   
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The literature on membranous nephropathy (MN) with monoclonal deposits on immunofluorescence (IF) and their outcome is very scarce. We report our experience of managing five patients with this clinical entity. The mean age of the patients was 33.2 ± 6.55 years. The mean proteinuria, serum albumin and serum creatinine was 5.73 ± 2.17 g/day, 2.86 ± 0.51 g/dL and 1.34 ± 1.19 mg/dL, respectively. None of the patients had a lymphoproliferative disorder. Only one patient had an elevated free light chain ratio. Four (80%) patients were M‐type phospholipase A2 receptor (PLA2R) negative (tissue and serum), and one (20%) was PLA2R related. Three (60%) cases had monoclonal IgG3/k, one IgG3/λ, whereas one patient with PLA2R positivity had an IgG3/IgG4k subtype. Two (67%) patients treated with cyclical cyclophosphamide and steroids (cCYC/GC) achieved complete remission and one patient (33%) with elevated baseline creatinine had a reduction in serum creatinine with persistent proteinuria at the end of the 12th month of follow‐up. One patient with PLA2R positive MN was treated with Rituximab and is in complete remission. The patient with an elevated free light chain at baseline was treated with Bortezomib/Thalidomide/Dexamethasone, had complete remission at 12 months, however, had a progressive rise in creatinine over the next 40 months of follow‐up. The current series, though limited by numbers, documents the efficacy of conventional therapies in non‐malignant associated MN with monoclonal deposits on IF.  相似文献   
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Factor VII deficiency is a rare congenital coagulopathy. Prolonged prothrombin time with normal partial thromboplastin time indicates factor VII deficiency. For the definitive diagnosis, the specific factor VII level should be investigated. We report a 20 day old, baby girl, born full-term who was admitted with the diagnosis of sepsis. Hematological tests revealed prolonged prothrombin time and a factor VII level of nine percent. After antibiotic therapy and fresh frozen plasma replacement, her clinical status improved but the prothrombin time continued to be prolonged. On the seventh day of discharge the baby died due to sudden intracranial hemorrhage.  相似文献   
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