Cerebrovascular reactivity (CVR) can give insight into the cerebrovascular function. CVR can be estimated by measuring a blood‐oxygen‐level‐dependent (BOLD) response combined with breath‐holding ...(BH). The reproducibility of this technique has been addressed and existing studies have focused on short‐term reproducibility using a 3 T magnetic resonance imaging (MRI) system. However, little is known about the long‐term reproducibility of this procedure and the corresponding reproducibility using a 1.5 T MRI system. Here, we systematically examined the short‐ and long‐term reproducibility of BOLD responses to BH across field strengths. Nine subjects participated in three MRI sessions separated by 30 minutes (sessions 1 and 2: short term) and 68–92 days (sessions 1 and 3, long term) at both 1.5 and 3 T MRI. Our findings revealed that significant differences between field strengths were detected in the activated gray matter volume and BOLD signal change (both P < 0.001), with smaller magnitudes at 1.5 T. However, activation patterns were reproducible, independent of the time interval, brain region or field strength. All interscan coefficient of variation values were below the 33% fiducial limit, and the intraclass correlation coefficient values were above 0.4, which is usually considered the acceptability limit in functional studies. These findings suggest that the response of BOLD signal to BH for assessing CVR is reproducible over time at 1.5 and 3 T. This technique can be considered a tool for monitoring longitudinal changes in patients with cerebrovascular diseases, and its use should be encouraged for clinical 1.5 T MRI systems.
Experimental conditions often hinder acquisition of artifact free spectra or impede acquisition of condition‐specific macromolecular spectra. Fitting estimates were unable to recover concentrations that were quantified from artefact free 1H MR spectra using an mismatched macromolecular basis spectrum. Estimation caused differences in quantified concentration for all of the neurochemicals that varied in magnitude among and within approaches. The spline was more tortuous when less constrained and when used in combination with estimated macromolecules and lipids.
Pneumonia is a common respiratory infectious disease that involves the inflammation of the pulmonary parenchyma. Periodontal disease is widespread and correlated with pneumonia. However, the ...relationship between periodontal treatment and clinical infectious outcomes in patients with pneumonia has remained undetermined. The aim of this study was to investigate the association between periodontal treatment and the risk of pneumonia events in the Taiwanese population. A nationwide population-based cohort study was conducted using data from the Taiwanese National Health Insurance Research Database (NHIRD). A total of 49,400 chronic periodontitis patients who received periodontal treatment from 2001 to 2012 were selected. In addition, 49,400 healthy individuals without periodontal diseases were picked randomly from the general population after propensity score matching according to age, gender, monthly income, urbanization, and comorbidities. The Cox proportional hazard regression analysis was adopted to assess the hazard ratio (HR) of pneumonia between the periodontal treatment cohort and the comparison cohort. The average ages of the periodontal treatment and comparison groups were 44.25 ± 14.82 years and 44.15 ± 14.5 years, respectively. The follow up durations were 7.66 and 7.41 years for the periodontal treatment and comparison groups, respectively. We found 2504 and 1922 patients with newly diagnosed pneumonia in the comparison cohort and the periodontal treatment cohort, respectively. The Kaplan-Meier plot revealed that the cumulative incidence of pneumonia was significantly lower over the 12 year follow-up period in the periodontal treatment group (using the log-rank test,
< 0.001). In conclusion, this nationwide population-based study indicated that the patients with periodontal treatment exhibited a significantly lower risk of pneumonia than the general population.
Background
Oral submucous fibrosis (OSF) is one of the well‐recognized oral potentially malignant disorders. In this study, we investigated the malignant transformation of OSF in a Taiwanese ...population.
Methods
A retrospective cohort study was analyzed from Taiwan's National Health Insurance Research Database. A comparison cohort was randomly frequency‐matched with the OSF cohort according to age, sex, and index year. Oral leukoplakia (OL) was further stratified to evaluate for the possible synergistic effects of OSF‐associated malignant transformation.
Results
In this cohort, 71 (9.13%) of 778 cases of OSF were observed to transform into oral cancer. The malignant transformation rate was 29.26‐fold in the OSF cohort than in the comparison cohort after adjustment (95% confidence intervals 20.55‐41.67). To further stratify with OL, OSF with OL (52.46%; 95% confidence intervals 34.88‐78.91) had higher risk of malignant transformation rate than OSF alone (29.84%; 95% confidence intervals 20.99‐42.42). The Kaplan‐Meier plot revealed the rate free of malignant transformation was significant over the 13‐year follow‐up period (log‐rank test, P<.001). The mean duration of malignant transformation was 5.1, 2.7, and 2.2 years for non‐OSF, OSF alone, and OSF with OL, respectively.
Conclusion
Oral submucous fibrosis patients exhibited a significantly higher risk of malignant transformation than those without OSF. OL could enhance malignant transformation in patients with OSF.
Background/Purpose Oral submucous fibrosis (OSF) has been regarded as a precancerous condition. Research examining the prevalence of OSF could be the first step in preventing or reducing malignant ...transformation. In this study, we probed a nationwide registered database to assess the prevalence, gender distribution, age, income, and urbanization status of OSF patients in Taiwan. Methods A retrospective study was conducted to analyze the registered database compiled by the National Health Insurance provided by the Ministry of Health and Welfare, Taiwan. We identified dental visit patients diagnosed with OSF during the period between January 1, 1996 and December 31, 2013. In addition, demographic characteristics were analyzed by multivariate Poisson regression. Results The prevalence of OSF increased significantly from 8.3 (per 105 ) in 1996 to 16.2 (per 105 ) in 2013 ( p < 0.0001). Men had a significantly higher OSF prevalence than women ( p < 0.001). The mean age of patients with OSF increased from 1996 to 2013. Individuals living in rural areas had a higher risk of OSF compared with those living in urban areas relative risk (RR), 1.10; 95% confidence interval (CI), 1.07–1.13. The higher income group had a lower risk of OSF compared with the lower income group (RR, 0.76; 95% CI, 0.73–0.80). Conclusion This large-scale government-centered survey demonstrates that the prevalence of OSF in Taiwan significantly increased from 1996 to 2013. The prevalence was higher among men than among women.
Abstract
Background
Altered neural activity based on the fractional amplitude of low-frequency fluctuations (fALFF) has been reported in patients with diabetes. However, whether fALFF can ...differentiate healthy controls from diabetic animals under anesthesia remains unclear. The study aimed to elucidate the changes in fALFF in a rat model of diabetes under isoflurane anesthesia.
Methods
The first group of rats (n = 5) received a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to cause the development of diabetes. The second group of rats (n = 7) received a single intraperitoneal injection of the same volume of solvent. Resting-state functional magnetic resonance imaging was used to assess brain activity at 4 weeks after STZ or solvent administration.
Results
Compared to the healthy control animals, rats with diabetes showed significantly decreased fALFF in various brain regions, including the cingulate cortex, somatosensory cortex, insula, and striatum (all P < 0.05). The decreased fALFF suggests the aberrant neural activities in the diabetic rats. No regions were detected in which the control group had a lower fALFF than that in the diabetes group.
Conclusions
The results of this study demonstrated that the fALFF could be used to differentiate healthy controls from diabetic animals, providing meaningful information regarding the neurological pathophysiology of diabetes in animal models.
Objective
Diffusion tensor imaging (DTI) is a useful approach for studying neuronal integrity in animals. However, the test–retest reproducibility of DTI techniques in animals has not been discussed. ...Therefore, the first part of this work was to systematically elucidate the reliability of DTI-derived parameters in an animal study. Subsequently, we applied the DTI approach to an animal model of diabetes in a longitudinal manner.
Materials and methods
In Study 1, nine rats underwent two DTI sessions using the same scanner and protocols, with a gap of 4 weeks. The reliability of the DTI-derived parameters was evaluated in terms of sessions and raters. In Study 2, nine rats received a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to develop diabetes. Longitudinal DTI scans were used to assess brain alterations before and 4 weeks after STZ administration.
Results
In the test–retest evaluation, the inter-scan coefficient of variation (CoV) ranged from 3.04 to 3.73% and 2.12–2.59% for fractional anisotropy (FA) and mean diffusivity (MD), respectively, in different brain regions, suggesting excellent reproducibility. Moreover, rater-dependence had minimal effects on FA and MD quantification, with all inter-rater CoV values less than 4%. Following the onset of diabetes, FA in striatum and cortex were noted to be significantly lower relative to the period where they had not developed diabetes (both
P
< 0.05). However, when compared to the control group, a significant change in FA caused by diabetes was detected only in the striatum (
P
< 0.05), but not in the cortex.
Conclusion
These results demonstrate good inter-rater and inter-scan reliability of DTI in animal studies, and the longitudinal setting has a beneficial effect on detecting small changes in the brain due to diseases.
The disparate or irregular dental care was associated with acute clinical problems that may lead to care seeking for emergency visits. The aim of this study was to determine the time trends, ...demographics, and conditions of emergency dental (ED) visits in Taiwan.
This cross-sectional study was conducted to analyze the insurance reimbursement of dental care services in National Health Insurance Research Database. The demographic characteristics and age-period effects of ED visits were estimated by multivariate Poisson regression. In addition, the top causes of ED visits were evaluated and stratified by traumatic and non-traumatic conditions.
The prevalence of ED visits were 3.18, 5.44, and 4.83 (per 10,000 persons) in 1997, 2002, and 2013, respectively. The primary diagnosis code for ED visits was 522 ‘pulp and periapical tissues’. Pulpitis (522.0), cellulitis (528.3), acute periodontitis (523.3), and caries (521.0) were the top 4 non-traumatic reasons for seeking ED visits. The top 3 traumatic conditions were open wound of internal structures of mouth without mention of complication (873.6), open wound of face without mention of complication (873.4), and loss of teeth due to trauma (525.1). The higher prevalence of ED visits were found in male (aRR = 1.50, 95% CI: 1.49–1.51), 6 y/o group (aRR = 1.56, 95% CI: 1.53–1.59), east region (aRR = 1.27, 95% CI: 1.25–1.29), and dependent coverage group (aRR = 1.16, 95% CI: 1.14–1.19).
Taken together, these demographic data could serve as a reference for the authorities concerned to improve the current situation of ED in Taiwan.
Periodontitis and psoriatic disease, including psoriasis (PS) and psoriatic arthritis (PsA), share the common risk factors and co-morbidities. However, the risk of periodontitis in patients with ...psoriatic disease still needs further investigation. This study was a nationwide population-based retrospective cohort study assessing the risk of periodontitis from psoriatic disease exposure.
Patients with newly diagnosed psoriatic disease from 2003 to 2012 were identified from the Taiwanese National Health Insurance Research Database. The 1:4 ratio propensity score matched controls were selected from no psoriatic disease participations. The subsequent risk of periodontitis was evaluated in exposure and comparison groups. Multiple Cox proportional hazard models were used for the estimation.
A total of 3,487 psoriatic disease patients and 13,948 controls were identified. Incidence rate of periodontitis was higher in patients with PsA. The adjusted hazard ratio (aHRs) for moderate/severe periodontitis were 0.85 (95% CI 0.65-1.11) in PS group and 1.66 (95% CI 0.99-2.78) in PsA group. The aHRs of PsA were increased over time, aHRs was changed from 0.65 (0-11 months from index date) to 1.34 (≥12 months from index date) in all types of periodontitis and from 1.09 to 1.79 in moderate/severe periodontitis group, respectively.
The increased risk of periodontitis was observed, especially the association between PsA and moderate/severe periodontitis. The patients with psoriatic disease should receive regular periodontal evaluation.
Cerebrovascular reactivity (CVR) is a specific indicator of autoregulatory efficiency. Studies have demonstrated that CVR depends on the baseline vascular dilation status between groups. Within the ...brain, there also exist spatial variations in both the resting cerebral blood flow (CBF) and CVR across different cerebral regions. However, the relationship between the regional CBF and CVR remains unclear. Hence, the primary goal of this study was to investigate the relationship between the resting CBF using pseudocontinuous arterial spin labeling (pCASL) technique and CVR using blood oxygenation level‐dependent (BOLD) technique across different cerebral regions. Eleven male and 14 female young volunteers were recruited in this study. Each subject was asked to perform the breath‐holding challenge to evaluate CVR at 3 T. The resting CBF was measured using pCASL in each subject. The relationships between CBF and CVR across the lobes were evaluated using the Spearman's rank test. The results showed that, for both sexes, the frontal lobe had the maximal resting perfusion but minimal vascular response to hypercapnia, whereas the occipital lobe had the lowest baseline CBF but maximal reactivity to hypercapnia, suggesting low and high autoregulatory efficiencies at high and low resting CBF in the brain, respectively. Sex‐related differences were observed in CBF but not in CVR. These findings may be of clinical interest in the assessment of cerebrovascular reserve and regional‐dependent vascular diseases.
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