Assessment of tissue heterogeneity using diffusion tensor and diffusion kurtosis imaging for grading gliomas

INTRODUCTION

In this work, we aim to assess the significance of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) parameters in grading gliomas.

METHODS

Retrospective studies were performed on 53 subjects with gliomas belonging to WHO grade II (n = 19), grade III (n = 20) and grade IV (n = 14). Expert marked regions of interest (ROIs) covering the tumour on T2-weighted images. Statistical texture measures such as entropy and busyness calculated over ROIs on diffusion parametric maps were used to assess the tumour heterogeneity. Additionally, we propose a volume heterogeneity index derived from cross correlation (CC) analysis as a tool for grading gliomas. The texture measures were compared between grades by performing the Mann-Whitney test followed by receiver operating characteristic (ROC) analysis for evaluating diagnostic accuracy.

RESULTS

Entropy, busyness and volume heterogeneity index for all diffusion parameters except fractional anisotropy and anisotropy of kurtosis showed significant differences between grades. The Mann-Whitney test on mean diffusivity (MD), among DTI parameters, resulted in the highest discriminability with values of P = 0.029 (0.0421) for grade II vs. III and P = 0.0312 (0.0415) for III vs. IV for entropy (busyness). In DKI, mean kurtosis (MK) showed the highest discriminability, P = 0.018 (0.038) for grade II vs. III and P = 0.022 (0.04) for III vs. IV for entropy (busyness). Results of CC analysis illustrate the existence of homogeneity in volume (uniformity across slices) for lower grades, as compared to higher grades. Hypothesis testing performed on volume heterogeneity index showed P values of 0.0002 (0.0001) and 0.0003 (0.0003) between grades II vs. III and III vs. IV, respectively, for MD (MK).

CONCLUSION

In summary, the studies demonstrated great potential towards automating grading gliomas by employing tumour heterogeneity measures on DTI and DKI parameters.

Targeted radiotherapy enhancement during electronic brachytherapy of accelerated partial breast irradiation (APBI) using controlled release of gold nanoparticles

Several studies have demonstrated low rates of local recurrence with brachytherapy-based accelerated partial breast irradiation (APBI). However, long-term outcomes on toxicity (e.g. telangiectasia) and cosmesis remain a major concern. The purpose of this study is to investigate the dosimetric feasibility of using targeted non-toxic radiosensitizing gold nanoparticles (GNPs) for localized dose enhancement to the planning target volume (PTV) during electronic brachytherapy APBI while reducing normal tissue toxicity. We propose to incorporate GNPs into a micrometer-thick polymer film on the surface of routinely used lumpectomy balloon applicators and provide subsequent treatment using a 50 kVp Xoft device. An experimentally determined diffusion coefficient was used to determine space-time customizable distribution of GNPs for feasible in-vivo concentrations of 7 mg/g and 43 mg/g. An analytical approach from previously published work was employed to estimate the dose enhancement due to GNPs as a function of distance up to 1 cm from the lumpectomy cavity surface. Clinically significant dose enhancement values of at least 1.2, due to 2 nm GNPs, were found at 1 cm away from the lumpectomy cavity wall when using electronic brachytherapy APBI. Higher customizable dose enhancement was also achieved at other distances as a function of nanoparticle size. Our preliminary results suggest that significant dose enhancement can be achieved to residual tumor cells targeted with GNPs during APBI with electronic brachytherapy.

Interscalene brachial plexus block for shoulder arthroscopic surgery: Prospective randomised controlled study of effects of 0.5% ropivacaine and 0.5% ropivacaine with dexamethasone

BACKGROUND AND AIMS

Various adjuvants have been used to prolong the duration of local anaesthetic action after peripheral and regional nerve blocks. We evaluated the effect of dexamethasone on the duration of pain relief in shoulder arthroscopic surgeries performed under interscalene brachial plexus using ropivacaine as local anaesthetic.

METHODS

After Ethical Committee approval and informed consent from patients we performed a prospective, randomised, comparative study on patients scheduled for arthroscopic shoulder surgery under interscalene block (ISB). Patients in ropivacaine group (Group R) received 30 ml of 0.5% ropivacaine plus 2 ml normal saline (n = 50) and dexamethasone-ropivacaine (Group RD) received 0.5% ropivacaine 30 ml plus 8 mg dexamethasone (4 mg/ml) (n = 50). Duration of analgesia, onset of sensory and motor block, success and failure of block, and complications were recorded and compared. Computer software SPSS version-16 (SPSS Inc., Chicago, Illinois, USA) was used for statistical analysis. Chi-square test and Student's t-test were used and P < 0.05 was considered as significant.

RESULTS

The mean duration of analgesia in Group RD was 1103.72 ± 296.027 min and in Group R it was 551.54 ± 166.92 min (P = 0.0001). Onset of sensory block in Group RD was 12.24 ± 1.88 min and in Group R was 13.48 ± 1.81 min (P = 0.5170). Onset of motor block in Group RD was 16.24 ± 2.04 min and in Group R was 17.76 ± 2.21 min (P = 0.2244). Onset of surgical anaesthesia in Group RD was19.46 ± 1.86 min and in Group R was 20.84 ± 1.71 min (P = 0.0859).

CONCLUSION

Dexamethasone significantly prolonged duration of analgesia of ropivacaine during ISB used for arthroscopic surgeries of shoulder. Dexamethasone when mixed with ropivacaine had no effect on the onset of sensory and motor effects of ISB with ropivacaine.

Adaptive k-space sampling design for edge-enhanced DCE-MRI using compressed sensing

The critical challenge in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is the trade-off between spatial and temporal resolution due to the limited availability of acquisition time. To address this, it is imperative to under-sample k-space and to develop specific reconstruction techniques. Our proposed method reconstructs high-quality images from under-sampled dynamic k-space data by proposing two main improvements; i) design of an adaptive k-space sampling lattice and ii) edge-enhanced reconstruction technique. A high-resolution data set obtained before the start of the dynamic phase is utilized. The sampling pattern is designed to adapt to the nature of k-space energy distribution obtained from the static high-resolution data. For image reconstruction, the well-known compressed sensing-based total variation (TV) minimization constrained reconstruction scheme is utilized by incorporating the gradient information obtained from the static high-resolution data. The proposed method is tested on seven real dynamic time series consisting of 2 breast data sets and 5 abdomen data sets spanning 1196 images in all. For data availability of only 10%, performance improvement is seen across various quality metrics. Average improvements in Universal Image Quality Index and Structural Similarity Index Metric of up to 28% and 24% on breast data and about 17% and 9% on abdomen data, respectively, are obtained for the proposed method as against the baseline TV reconstruction with variable density random sampling pattern.

Analysis of carbapenem-resistant Acinetobacter from a tertiary care setting in North India

Multidrug-resistant (MDR) Acinetobacter baumannii is a worldwide concern as cause of serious nosocomial infections. We analysed 140 non-duplicate Acinetobacter sp. isolates from hospitalised patients in a tertiary care centre; 87% were MDR and 20% (28/140) meropenem resistant. Metallo-β-lactamase was produced by 16 of these, detected by ethylene-diamine-tetra-acetic acid disc synergy test. AmpC β-lactamase and efflux pump were present in 17 and 4 of the meropenem-resistant Acinetobacter, respectively. 9/16 MBL-positive isolates carried genes for carbapenem resistance as shown by polymerase chain reaction.

Caregiver characteristics and economic cost of home-based care: a case study of Maun and Gumare villages in North West District, Botswana

The home-based care programme in Botswana was initiated partly to augment hospital or clinical care by reducing the healthcare costs associated with chronic illnesses such as HIV/AIDS. A number of studies have pointed to the psyco-social impacts of home based care, however there has been few attempts to quantify the direct and indirect costs associated with home based care. This study was carried out in the North West District of Botswana, which is noted for a relatively larger proportion of households with critically ill persons. The objectives of the study were to identify the characteristics of the caregivers and their patients; to estimate the direct and indirect costs of home-based care; and to estimate caregivers' willingness to pay for care services. Data was collected using a structured questionnaire addressed to 120 primary caregivers and analyzed using SPSS. The economic cost of caregiving was estimated using the replacement cost method. The annual value per caregiver was estimated at P31 320 (US$4818.46). The study also revealed that more often than not, women are involved in caregiving activities.

Gossypiboma mimicking posterior urethral stricture

INTRODUCTION

Foreign bodies in the urogenital tract are not uncommon. Hairpins, glass rods, umbilical tapes, ball point pen are described in lower urogenital tract. Retained gauze piece (gossypiboma) in posterior urethra may cause diagnostic dilemma. Symptoms and investigations may mimic stricture of posterior urethra.

PRESENTATION OF CASE

Two cases of retained gauze pieces in the urethra are described here. The micturating cystourethrogram was suggestive of posterior urethral stricture.

DISCUSSION

Two cases described here had retained gauze piece as a cause of filling defect and abnormal appearance in the micturating cystourethrogram. Gossypiboma may be a possibility where posterior urethral stricture are seen after previous surgery in paediatric age group.

CONCLUSION

In the setting of previous urogenital surgery gossypiboma should be kept in the differential diagnosis where posterior urethral stricture are seen in the paediatric age group.

Biliary atresia with aneurysmal dilatation of hepatic artery: A rare anomaly

INTRODUCTION

The coexistent biliary atresia with aneurysmal dilatation of hepatic artery is a rare association. To know these anomalies will avoid many per operative complications. It is also important to mention that these children require liver transplantation in the long run then these vascular anomalies become more relevant.

PRESENTATION OF CASE

A four month old male child presented with features of biliary atresia. On exploration a cystic expansile mass was detected beneath thread like common bile duct. Subsequent aspiration and studies proved it to be aneurysmal dilatation of hepatic artery.

DISCUSSION

With biliary atresia many vascular and cardiac malformations have been described but aneurysmal dilatation of hepatic artery is a rare association. These anomalies may have impact on aetiopathogenesis of biliary atresia and also future liver transplantation.

CONCLUSION

Awareness of rare association of hepatic artery aneurysm with biliary atresia will help in understanding aetiopathogenesis of biliary atresia and planning liver transplantation in such cases.