Ashish Awasthi

Discriminant analysis to classify glioma grading using dynamic contrast-enhanced MRI and immunohistochemical markers.

IntroductionThe purpose of the present study was to look for the possible predictors which might discriminate between high- and low-grade gliomas by pooling dynamic contrast-enhanced (DCE)-perfusion derived indices and immunohistochemical markers.MethodsDCE-MRI was performed in 76 patients with different grades of gliomas. Perfusion indices, i.e., relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), permeability (ktrans and kep), and leakage (ve) were quantified. MMP-9-, PRL-3-, HIF-1α-, and VEGF-expressing cells were quantified from the excised tumor tissues. Discriminant function analysis using these markers was used to identify discriminatory variables using a stepwise procedure. To look for correlations between immunohistochemical parameters and DCE metrics, Pearsons correlation coefficient was also used.ResultsA discriminant function for differentiating between high- and low-grade tumors was constructed using DCE-MRI-derived rCBV, kep, and ve. The form of the functions estimated are “D1 = 0.642 × rCBV + 0.591 × kep − 1.501 × ve − 1.550” and “D2 = 1.608 × rCBV + 3.033 × kep + 5.508 × ve − 8.784” for low- and high-grade tumors, respectively. This function classified overall 92.1% of the cases correctly (89.1% high-grade tumors and 100% low-grade tumors). In addition, VEGF expression correlated with rCBV and rCBF, whereas MMP-9 expression correlated with kep. A significant positive correlation of HIF-1α with rCBV and VEGF expression was also found.ConclusionDCE-MRI may be used to differentiate between high-grade and low-grade brain tumors non-invasively, which may be helpful in appropriate treatment planning and management of these patients. The correlation of its indices with immunohistochemical markers suggests that this imaging technique is useful in tissue characterization of gliomas.

Diffusion tensor tractography indices in patients with frontal lobe injury and its correlation with neuropsychological tests.

OBJECTIVES Diffusion tensor tractography (DTT) was performed to quantify diffuse axonal injury (DAI) in major white matter (WM) fiber bundles (FBs) of patients with frontal lobe injury and to correlate these changes with neuropsychological tests (NPT) at 6 month follow-up. PATIENTS AND METHODS DTT was performed in 21 patients with moderate traumatic brain injury (TBI) within week and after 6 month follow-up, and in controls. DTI indices were calculated from the entire FBs in patients as well as controls. Bonferroni multiple comparisons Post hoc test was performed for determining the changes in DTI indices. Paired t-test was performed between DTI indices at baseline and follow-up. Pearsons correlation was performed between NPT scores and DTI indices. RESULTS Significant changes in DTI indices were observed in some of the FBs as compared to controls which incompletely recovered at 6 month follow-up. DTI indices of different WM FBs correlated significantly with some of the NPT. CONCLUSION We conclude that DTT based quantification helps in assessment of DAI in patients with moderate frontal lobe injury. Some of the FBs recover partially at 6 month follow-up and correlate with NPT scores.

Utility of Osteoporosis Self-Assessment Tool as a Screening Tool for Predicting Osteoporosis in Indian Men

The osteoporosis self-assessment tool (OSTA) predicts the risk of osteoporosis in an individual. It is a simple calculation-based tool [wt (kg) - age (yr)/5] and can be used for measuring bone mineral density (BMD). However, OSTA is influenced by ethnicity. We studied the performance of OSTA index as a screening tool for osteoporosis in 257 community-dwelling North Indian men above 50 yr age. Each subject underwent a detailed clinical, dietary, anthropometric, and biochemical assessment and bone density measurement using dual-energy X-ray absorptiometry. As per World Health Organization criteria, osteoporosis, osteopenia, and normal BMD were observed in 17.9%, 58.8%, and 23.3%, respectively. OSTA index ranged between -6.4 and 8.8. OST index ≤2 predicted osteoporosis with a sensitivity of 95.7% and a specificity of 33.6% and an area under the curve for a receiver operating characteristic curve of 0.702. The OSTA index is an effective screening tool for measuring BMD in elderly Indian men and can be used by primary care physicians.

Disparity in maternal, newborn and child health services in high focus states in India: a district-level cross-sectional analysis

Objectives To examine the level and trend in the coverage gap of a set of interventions of maternal and child health services using a summary index and to assess the disparity in usage of maternal and child health services in the districts of high focus states of India. Design Data for the present study are taken from the Annual Health Survey (AHS), 2010–2013 and Census of India, 2011. Settings This study used secondary data from states having higher mortality and fertility rates, termed as high focus states in India. Participants District-level information regarding children aged 12–23 months and ever married women aged 15–49 years has been extracted from the AHS (2010–2013), and household amenities, female literacy and main workforce information has been obtained from the Census of India 2011. Measures 2 summary indexes were calculated first for maternal and child health services and another for socioeconomic and development status, using data from AHS and Census. Cronbachs α was used to assess the internal consistency of the items used in the index. Results The result shows that the coverage gap is highest in Uttar Pradesh (37%) and lowest in Madhya Pradesh (21%). Converge gap and socioeconomic development are negatively correlated (r=−0.49, p=0.01). The average coverage gap was highest in the lowest quintile of socioeconomic development. There was an absolute change of 1.5% per year in coverage gap during 2009–2013. In regression analysis, the coefficient of determination was 0.24, β=−30.05, p=0.01 for a negative relationship between socioeconomic development and coverage gap. Conclusions There is a significant disparity in the usage of maternal and child healthcare services in the districts of India. Resource-rich people (urban residents and richest quintile) are way ahead of marginalised people (rural residents and poorest quintile) in the usage of healthcare services.

Intermediate outcomes of rheumatic mitral stenosis post-balloon mitral valvotomy.

Background Balloon mitral valvotomy is a standard therapeutic modality for managing rheumatic mitral stenosis. Data on intermediate outcomes of this procedure are limited. Thus we investigated the intermediate outcome after balloon mitral valvotomy performed at a large tertiary center in India. Methods Case records and follow-up data of 2330 patients who underwent valvotomy from June 1999 to December 2005 were retrieved from the hospital information system and analyzed. Results The median age of the patients was 32 ± 11 years, 1363 were female including 36 who were pregnant, and 379 were in atrial fibrillation. Follow-up ranged from 1 to 14 years (mean 4.5 years, median 4.0 years). The procedural success rate was 93%. Atrial fibrillation, higher functional class, and worse valve morphology were independent predictors of a poor procedural outcome. Patients with sinus rhythm had better event-free survival (10.43 years, 95% confidence interval: 10.1–10.7) compared to those with atrial fibrillation (8.17 years, 95% confidence interval: 7.5–8.8). Patients who achieved a valve area >1.75 cm2 had a better event-free survival (11.7 years, 95% confidence interval: 11.4–12.0) than those with a valve area of 1.5–1.74 cm2 (9.3 years, 95% confidence interval: 9.0–9.7). On multivariate analysis, higher functional class, worse valve morphology, and new significant mitral regurgitation were predictors of a poor outcome. Achieved mitral valve area >1.75 cm2 was an independent predictor of a good outcome. Conclusion Patients with sinus rhythm, less gross valve deformity, and a post-balloon mitral valvotomy area >1.75 cm2 had better intermediate outcomes.

Arterial spin labeling magnetic resonance perfusion study to evaluate the effects of age and gender on normal cerebral blood flow

PURPOSE Arterial spin labeling (ASL) is a noninvasive magnetic resonance (MR) perfusion technique to detect changes in blood flow. This study was undertaken to obtain a reference set of normal values of cerebral blood flow (CBF) in different age groups using three-dimensional pseudocontinuous ASL (3D PCASL) technique. The existence of an age-related decline in the gray matter (GM) and white matter (WM) CBF was evaluated. The gender-related CBF was also analyzed. MATERIALS AND METHODS One hundred and sixty normal volunteers of varying age (6-72 years), arranged in 4 age groups, underwent MR perfusion imaging using 3D PCASL technique at 3 Tesla (T). Mean CBF values in global and regional GM and WM in different age groups were extracted from the quantitative perfusion map. RESULTS A significant negative correlation was observed between the age and mean GM and WM CBF values (r = -0.80, P = 0.001; r = -0.59, P = 0.001, respectively). Similar results were also observed between age and various regional mean GM and WM CBF values (P = 0.001). No significant effect of gender on the GM CBF and WM CBF was found in any age group (P > 0.05). CONCLUSION PCASL technique provides reliable quantitative parameters for the precise mapping of age-related perfusion changes occurring in the normal brain.

Diagnostic accuracy of automatic normalization of CBV in glioma grading using T1- weighted DCE-MRI

PURPOSE Aim of this retrospective study was to compare diagnostic accuracy of proposed automatic normalization method to quantify the relative cerebral blood volume (rCBV) with existing contra-lateral region of interest (ROI) based CBV normalization method for glioma grading using T1-weighted dynamic contrast enhanced MRI (DCE-MRI). MATERIAL AND METHODS Sixty patients with histologically confirmed gliomas were included in this study retrospectively. CBV maps were generated using T1-weighted DCE-MRI and are normalized by contralateral ROI based method (rCBV_contra), unaffected white matter (rCBV_WM) and unaffected gray matter (rCBV_GM), the latter two of these were generated automatically. An expert radiologist with >10years of experience in DCE-MRI and a non-expert with one year experience were used independently to measure rCBVs. Cutoff values for glioma grading were decided from ROC analysis. Agreement of histology with rCBV_WM, rCBV_GM and rCBV_contra respectively was studied using Kappa statistics and intra-class correlation coefficient (ICC). RESULT The diagnostic accuracy of glioma grading using the measured rCBV_contra by expert radiologist was found to be high (sensitivity=1.00, specificity=0.96, p<0.001) compared to the non-expert user (sensitivity=0.65, specificity=0.78, p<0.001). On the other hand, both the expert and non-expert user showed similar diagnostic accuracy for automatic rCBV_WM (sensitivity=0.89, specificity=0.87, p=0.001) and rCBV_GM (sensitivity=0.81, specificity=0.78, p=0.001) measures. Further, it was also observed that, contralateral based method by expert user showed highest agreement with histological grading of tumor (kappa=0.96, agreement 98.33%, p<0.001), however; automatic normalization method showed same percentage of agreement for both expert and non-expert user. rCBV_WM showed an agreement of 88.33% (kappa=0.76,p<0.001) with histopathological grading. CONCLUSION It was inferred from this study that, in the absence of expert user, automated normalization of CBV using the proposed method could provide better diagnostic accuracy compared to the manual contralateral based approach.

Comparison of actual with default hematocrit value in dynamic contrast enhanced MR perfusion quantification in grading of human glioma

PURPOSE Dynamic contrast enhanced (DCE) MRI is used to grade and to monitor the progression of glioma while on treatment. Usually, a fixed hematocrit (Hct) value for adults is assumed to be ~45%; however, it is actually known for individual variations. Purpose of this study was to investigate the effect of measured Hct values in glioma grading using DCE-MRI. MATERIALS AND METHODS Fifty glioma patients were included in this study. Kinetic and hemodynamic parameters were estimated for each patient using assumed as well as measured Hct values. To look the changes in Hct value over time, Hct was measured multiple times from 10 of these glioma patients who were on treatment. Simulation was done to look for the effect of extreme variations of Hct values on perfusion metrics. The data was compared to look for significant differences in the perfusion metrics derived from assumed and measured Hct values. RESULTS The measured Hct value in patients was found to be (40.4±4.28)%. The sensitivity and specificity of DCE-MRI parameters in glioma grading were not significantly influenced by using measured vis-a-vis assumed Hct values. The serial Hct values from 10 patients who were on treatment showed a fluctuation of 15-20% over time. The simulated data showed linear influence of Hct values on kinetic parameters. The tumor grading was altered on altering the Hct values in borderline cases. CONCLUSION Hct values influence the hemodynamic and kinetic metrics linearly and may affect glioma grading. However, perfusion metrics values might change significantly with large change in Hct values, especially in patients who are on chemotherapy necessitating its use in the DCE model.

Multiparametric imaging-based differentiation of lymphoma and glioblastoma: using T1-perfusion, diffusion, and susceptibility-weighted MRI

AIM To compare the diagnostic performance of T1 perfusion magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and susceptibility-weighted imaging (SWI) for differentiating primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). MATERIALS AND METHODS This retrospective study comprised a cohort of 70 patients with glioblastoma and 30 patients with PCNSL. T1 perfusion MRI-derived rCBV_corr (leakage corrected relative cerebral blood volume), apparent diffusion coefficient (ADC) derived from DWI, and intratumoural susceptibility signals intensity (ITSS) measured on SWI were evaluated in these 100 patients. The Mann-Whitney U-test was used for pairwise comparison between groups. The diagnostic performance for differentiating PCNSL from glioblastoma was evaluated by using univariate and multivariable logistic regression analyses and receiver operating characteristic (ROC) analysis. RESULTS Minimum ADC, maximum rCBVs_corr, kep (back flux exchange rate), and ITSS scores were significantly lower in patients with PCNSL than in those with glioblastoma (p<0.05). On ROC analysis, ITSS showed the best discrimination ability for differentiation of GBM and PCNSL with an area under the ROC curve (AUC) of 0.80. rCBV_corr and ADC showed AUCs of 0.68 and 0.63, respectively. Multiparametric assessment using ADC, rCBV_corr, kep, and ITSS scores significantly increased the diagnostic ability for differentiating PCNSL from GBM as compared to mean ADC, mean rCBV_corr, and ITSS alone or a combination of these parameters. The multiparametric model could correctly discriminate 84% of tumours with a sensitivity and specificity of 90% and 70% with an AUC of 0.92. CONCLUSION Multiparametric MRI evaluation using DWI, T1 perfusion MRI, and SWI enabled reliable differentiation of PCNSL and GBM in the majority patients, and these results support an integration of advanced MRI techniques for the diagnostic work-up of patients with these tumours.