Monoexponential, biexponential and stretched exponential models of diffusion weighted magnetic resonance imaging in glioma in relation to histopathologic grade and Ki-67 labeling index using high B values.

PURPOSE: To explore the performance of various parameters obtained from monoexponential (Gaussian), biexponential and stretched exponential (non-Gaussian) models of Diffusion Weighted Magnetic Resonance Imaging in differentiating gliomas with correlation to histopathology and Ki-67 labeling index (LI). MATERIALS AND METHODS: This Institute Review Board approved retrospective study included 51 pathologically proven glioma patients (WHO Grade I, n = 1; Grade II, n = 19, Grade III, n = 12; Grade IV, n = 19), and immunohistochemistry for Ki-67 LI was obtained. The conventional Magnetic Resonance (MR) images and Diffusion Weighted (DW) images with 19 non-zero b values (0-4500 s/mm2) followed by contrast-enhanced MR images were obtained at 3T preoperatively. All images were processed with Advantage Workstation 4.5 (GE Medical Systems). Region of interest (ROI) in the solid part of the tumor was manually drawn along the border meticulously excluding areas of edema, cyst, hemorrhage, necrosis, and/or calcification, and the parameters: Apparent Diffusion Coefficient (ADC) of monoexponential; pure molecular diffusion coefficient (Dslow), pseudo-diffusion coefficient (Dfast), and perfusion fraction (f) of biexponential; Distributed Diffusion Coefficient (DDC), and heterogeneity index (α) of stretched exponential models were obtained. ROI of 50 mm2 in the contralateral normal appearing white matter (NAWM) was drawn for the internal control either on centrum semiovale or white matter of the frontal lobe. Analysis of reliability by Intra-class Correlation Coefficient (ICC); correlation with Ki-67 LI by Spearman's rank correlation; comparison between high grade glioma (HGG) and low grade glioma (LGG) by either Mann Whitney U test or Independent t-Test; comparison among Grade II, III and IV gliomas by one-way ANOVA with Bonferroni; and diagnostic performance by analysis of Area Under Receiver Operating Characteristic (ROC) Curve (AUC) were conducted. RESULTS: Highly significant differences were found between HGG and LGG for all the parameters (P < 0.001 for all). In differentiating HGG from LGG, AUC values were 0.955 for Ki-67 LI; 0.926 for α; 0.903 for Dslow; 0.897 for f; 0.863 for DDC; 0.852 for ADC; 0.820 for Dfast (P < 0.001 for all). The parameters ADC, Dslow, Dfast, f, DDC, and α showed moderate to good negative correlation with Ki-67 LI (P < 0.001 for all). The ICCs of all the parameters were found greater than 0.75 (P < 0.05 for all) suggesting good reliability of measurements. CONCLUSION: In comparison to ADC derived from monoexponential model, the parameters α and Dslow derived from stretched exponential, and biexponential models respectively can efficiently differentiate HGG from LGG with high diagnostic accuracy. Additionally, f and DDC derived from biexponential, and stretched exponential models respectively are also more useful in differentiating HGG from LGG in comparison to ADC.

Age and anatomical location related hemodynamic changes assessed by 4D flow MRI in the carotid arteries of healthy adults.

PURPOSE: To evaluate hemodynamic changes (volume, velocity, wall shear stress, pressure gradient, and energy loss) in the common carotid artery (CCA) and internal carotid artery (ICA) of healthy adults among different ages and anatomical locations using 4D flow MRI. METHODS: Sixty-two healthy volunteers aged 20-75 years were enrolled in this study. 4D flow MRI examinations were performed for each subject and were analyzed using the CVI42 platform to generate hemodynamic parameters. Hemodynamic parameters were compared among different age groups and anatomical locations (proximal CCA, distal CCA, proximal ICA and distal CCA) using one-way ANOVA. The paired t-test was used to estimate the differences between left and right vessels. The relationship between age and hemodynamic parameters was quantified by Pearson's correlation coefficient. RESULTS: There were no differences between the left and right carotid arteries for any of the hemodynamic parameters (all p values > 0.05), so we set each vessel as an independent sample. The proximal ICA had significantly lower volume, velocity, wall shear stress, and pressure gradient values than the values determined for other locations (p < 0.05), and energy loss was similar among different locations. Wall shear stress (except in the distal ICA), velocity, pressure gradient, and energy loss decreased with age (p < 0.05). CONCLUSIONS: The multiparameter analysis of 4D flow MRI can identify age and anatomical location changes in hemodynamic parameters in the carotid arteries of healthy adults. The lower velocity, wall shear stress, and pressure gradient in the proximal ICA and the reduced trend with age may be associated with disease occurrence.

Prevalence of Cardiovascular Risk Factors in Apparently Healthy Urban Adult Population of Kathmandu.

BACKGROUND: Cardiovascular diseases account for most deaths and major proportion of disabilities worldwide. Major cardiovascular risk factors are implicated in almost 75% of cardiovascular diseases. There has been a rapid increase in prevalence of such risk factors in apparently healthy young adults of urban population. This study aimed to find prevalence of such risk factors in order to implement preventive strategies against cardiovascular diseases in our setting. METHODS: A free heart camp was organized following wide dissemination of information through print, online, TV, radio and social media. Pretested data collection tool was used by trained enumerators using standard guidelines and calibrated devices. Demographic, anthropometric, physical examination and blood investigation data were obtained. Standard guidelines were followed to define and categorize the obtained information. Data was analyzed using SPSS V20. RESULTS: A total of 5530 participants were enrolled after carefully applying inclusion and exclusion criteria. Mean age of study population was 38.14±13.03 years. There were 3298 (59.6%) males with mean age of 37.67±12.99 years and 2232 (40.4%) females with mean age of 38.84±13.05 years. Majority of study population (29.6%) belonged to 30-39 years age group. Prevalence of tobacco and alcohol consumption was 29.3%(95%CI:28.1-30.5) and 32.7%(95%CI:31.5-34.) respectively. Prevalence of inadequate fruits and vegetables intake, low physical activity and overweight or obesity was 75.4%(95%CI:74.3-76.6), 61.1%(95%CI:59.8-62.4) and 41.3%(95%CI:40.0-42.6) respectively. Prevalence of hypertension, diabetes and dyslipidemia was 26.4%(95%CI:25.3-27.6), 5.3%(95%CI:4.7-5.9) and 86.9%(95%CI:85.9-87.7) respectively. These results were statistically significant in both age and sex based distribution. CONCLUSIONS: Prevalence of major cardiovascular risk factors in apparently healthy adult population of Kathmandu Valley was high. Dyslipidemia, unhealthy diet, physical inactivity and overweight or obesity were most prevalent cardiovascular risk factors.

Correction to: Arthroscopic release using F and C method versus conventional open release method in the treatment of gluteal muscle contracture: a comparative study.

Upon publication of this article [1], it was requested that: the corresponding author, Hong Wang's affiliation address be changed from.

Bleeding events associated with a low dose (110 mg) versus a high dose (150 mg) of dabigatran in patients treated for atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: The newer oral anticoagulant dabigatran is considered to be more beneficial in patients with non-valvular Atrial Fibrillation (AF) when compared to warfarin. However, because bleeding events which are associated with a low dose (110 mg) versus a high dose (150 mg) of dabigatran have seldom been compared, we aimed to systematically solve this important issue through this meta-analysis. METHODS: English publications comparing 110 mg with 150 mg dabigatran in patients who were treated for AF were electronically searched through medical databases. Bleeding outcomes were the major clinical endpoints to be assessed. Odds Ratios (OR) and 95% Confidence Intervals (CIs) for each subgroup were calculated and the main analysis was carried out by the latest version of the RevMan 5.3 software. RESULTS: Twenty-nine thousand two hundred and sixty-four (29,264) patients were included in this meta-analysis. Fifteen thousand eight hundred and forty-eight (15,848) patients were treated with 110 mg dabigatran whereas 13,416 patients were treated with 150 mg dabigatran. 110 mg dabigatran was associated with a significantly lower rate of minor bleeding (OR: 1.19, 95% CI: 1.10-1.27; P < 0.00001). A similar rate of fatal and major bleeding was observed with both dosages (OR: 1.12, 95% CI: 0.69-1.82; P = 0.65) and (OR: 1.09, 95% CI: 0.86-1.37; P = 0.49) respectively. However, ischemic stroke insignificantly favored a higher dose of dabigatran, (OR: 0.77, 95% CI: 0.51-1.16; P = 0.21). In addition, this analysis showed mortality to significantly favor 150 mg of dabigatran (OR: 0.41, 95% CI: 0.34-0.50; P < 0.00001). CONCLUSION: No significant differences in major and fatal bleedings were observed with 110 mg versus 150 mg dabigatran. However, 110 mg dabigatran was associated with a significantly lower risk of minor bleeding. These results should further be confirmed in future trials.

Arthroscopic release using F and C method versus conventional open release method in the treatment of gluteal muscle contracture: a comparative study.

BACKGROUND: Gluteal muscle contracture (GMC), a debilitating disease, usually starts in early childhood after variable dose of injections around the buttock, if left untreated it worsens gradually and persists throughout the life. Because the disease mostly affects adolescents and adults, there is always an aesthetic concerns. Purposeof the study was to introduce the arthroscopic F and C method of GMC release, and to compare its clinical efficiency with conventional open surgery in terms of clinical outcome, rate of complications, patient's satisfactions, and recurrence. METHODS: Between Jan 2013 and July 2015, 75 patients received an arthroscopic release with F and C release method and 71 patients received conventional open release of GMC. Primary surgeries in 16 years or older patients were included in the study. Two groups were compared clinically using Hip Outcome Scores - Activities of Daily Living Subscale (HOS-ADL), Hip Outcome Scores - Sports Subscale (HOS-Sports), Visual Analogue Scale (VAS), and Ye et al. evaluation criteria. RESULTS: No statistically significant differences were observed in Hip Outcome Scores - Activities of Daily Living Subscale (HOS-ADL) (P = 0.078), Hip Outcome Scores - Sports Subscale (HOS-Sports) (P = 0.340), and Visual Analogue Scale (VAS) (P = 0.524) between the two groups. 74 (98.7%) patients in the arthroscopic surgery group had good to excellent results, whereas 69 (97.1%) patients in the conventional open surgery group had good to excellent results (P = 0.727). No statistically significant difference was observed in recurrence rate (P = 0.612). Statistically significant differences were observed in incision length, use of post-operative analgesia, post-operative off-bed activity, and hospital stay. Complications were significantly higher in the conventional open surgery group (n = 21) than in the arthroscopic surgery group (n = 10) (P = 0.016). More importantly, cosmetic satisfaction was 100% in arthroscopic release group, whereas only 71% had cosmetic satisfaction in conventional open surgery group (P < 0.001). CONCLUSION: Both, arthroscopic surgery and conventional open surgery, are highly effective tools for the GMC release in adolescent and adult patients. Arthroscopic GMC release with F and C method allows precise and selective release of contracture bands with small surgical trauma resulting fewer complications, high cosmetic satisfaction and minimal recurrence.

Evaluation of different mathematical models and different b-value ranges of diffusion-weighted imaging in peripheral zone prostate cancer detection using b-value up to 4500 s/mm2.

OBJECTIVES: To evaluate the diagnostic performance of different mathematical models and different b-value ranges of diffusion-weighted imaging (DWI) in peripheral zone prostate cancer (PZ PCa) detection. METHODS: Fifty-six patients with histologically proven PZ PCa who underwent DWI-magnetic resonance imaging (MRI) using 21 b-values (0-4500 s/mm2) were included. The mean signal intensities of the regions of interest (ROIs) placed in benign PZs and cancerous tissues on DWI images were fitted using mono-exponential, bi-exponential, stretched-exponential, and kurtosis models. The b-values were divided into four ranges: 0-1000, 0-2000, 0-3200, and 0-4500 s/mm2, grouped as A, B, C, and D, respectively. ADC, , D*, f, DDC, α, Dapp, and Kapp were estimated for each group. The adjusted coefficient of determination (R2) was calculated to measure goodness-of-fit. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of the parameters. RESULTS: All parameters except D* showed significant differences between cancerous tissues and benign PZs in each group. The area under the curve values (AUCs) of ADC were comparable in groups C and D (p = 0.980) and were significantly higher than those in groups A and B (p< 0.05 for all). The AUCs of ADC and Kapp in groups B and C were similar (p = 0.07 and p = 0.954), and were significantly higher than the other parameters (p< 0.001 for all). The AUCs of ADC in group D was slightly higher than Kapp (p = 0.002), and both were significantly higher than the other parameters (p< 0.001 for all). CONCLUSIONS: ADC derived from conventional mono-exponential high b-value (3200 s/mm2) models is an optimal parameter for PZ PCa detection.

Gluteal muscle contracture: diagnosis and management options.

Gluteal muscle contracture (GMC), a debilitating disease, exists all over the globe but it is much more prevalent in China. Patients typically present with abduction and external rotation of the hip and are unable to bring both the knees together while squatting. Multiple etiologies have been postulated, the commonest being repeated intramuscular injection into the buttocks. The disease is diagnosed primarily by clinical features but radiological features are necessary for the exclusion of other pathological conditions. Non-operative treatment with physiotherapy can be tried before surgery is considered but it usually fails. Different surgical techniques have been described and claimed to have a better outcome of one over another but controversy still exists. Based on published literatures, the clinical outcome is exceptionally good in all established methods of surgery. However, endoscopic surgery is superior to conventional open surgery in terms of cosmetic outcome with fewer complications. Nevertheless, its use has been limited by lack of adequate knowledge, instrumentations, and some inherent limitations. Above all, post-operative rehabilitation plays a key role in better outcome, which however should be started gradually.

Comparing the clinical outcomes in patients with atrial fibrillation receiving dual antiplatelet therapy and patients receiving an addition of an anticoagulant after coronary stent implantation: A systematic review and meta-analysis of observational studies.

BACKGROUND: Data regarding the clinical outcomes in patients with atrial fibrillation (AF) receiving dual antiplatelet therapy (DAPT) and an anticoagulant in addition to DAPT (DAPT + vitamin K antagonist [VKA]) after coronary stent implantation are still controversial. Therefore, in order to solve this issue, we aim to compare the adverse clinical outcomes in AF patients receiving DAPT and DAPT + VKA after percutaneous coronary intervention and stenting (PCI-S). METHODS: Observational studies comparing the adverse clinical outcomes such as major bleeding, major adverse cardiovascular events, stroke, myocardial infarction, all-cause mortality, and stent thrombosis (ST) in AF patients receiving DAPT + VKA therapy, and DAPT after PCI-S have been searched from Medline, EMBASE, and PubMed databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to express the pooled effect on discontinuous variables, and the pooled analyses were performed with RevMan 5.3. RESULTS: Eighteen studies consisting of a total of 20,456 patients with AF (7203 patients received DAPT + VKA and 13,253 patients received DAPT after PCI-S) were included in this meta-analysis. At a mean follow-up period of 15 months, the risk of major bleeding was significantly higher in DAPT + VKA group, with OR 0.62 (95% CI 0.50-0.77, P < 0.0001). There was no significant differences in myocardial infarction and major adverse cardiovascular event between DAPT + VKA and DAPT, with OR 1.27 (95% CI 0.92-1.77, P = 0.15) and OR 1.17 (95% CI 0.99-1.39, P = 0.07), respectively. However, the ST, stroke, and all-cause mortality were significantly lower in the DAPT + VKA group, with OR 1.98 (95% CI 1.03-3.81, P = 0.04), 1.59 (95% CI 1.08-2.34, P = 0.02), and 1.41 (95% CI 1.03-1.94, P = 0.03), respectively. CONCLUSION: At a mean follow-up period of 15 months, DAPT + VKA was associated with significantly lower risk of stroke, ST, and all-cause mortality in AF patients after PCI-S compared with DAPT group. However, the risk of major bleeding was significantly higher in the DAPT + VKA group.