Predictors of unfavorable responses to therapy in rifampicin-sensitive pulmonary tuberculosis using an integrated approach of radiological presentation and sputum mycobacterial burden.

INTRODUCTION: Despite the exalted status of sputum mycobacterial load for gauging pulmonary tuberculosis treatment and progress, Chest X-rays supplement valuable information for taking instantaneous therapeutic decisions, especially during the COVID-19 pandemic. Even though literature on individual parameters is overwhelming, few studies have explored the interaction between radiographic parameters denoting severity with mycobacterial burden signifying infectivity. By using a sophisticated approach of integrating Chest X-ray parameters with sputum mycobacterial characteristics, evaluated at all the three crucial time points of TB treatment namely pre-treatment, end of intensive phase and completion of treatment, utilizing the interactive Cox Proportional Hazards model, we aimed to precisely deduce predictors of unfavorable response to TB treatment. MATERIALS AND METHOD: We extracted de-identified data from well characterized clinical trial cohorts that recruited rifampicin-sensitive Pulmonary TB patients without any comorbidities, taking their first spell of anti-tuberculosis therapy under supervision and meticulous follow up for 24 months post treatment completion, to accurately predict TB outcomes. Radiographic data independently obtained, interpreted by two experienced pulmonologists was collated with demographic details and, sputum smear and culture grades of participants by an independent statistician and analyzed using the Cox Proportional Hazards model, to not only adjust for confounding factors including treatment effect, but also explore the interaction between radiological and bacteriological parameters for better therapeutic application. RESULTS: Of 667 TB patients with data available, cavitation, extent of involvement, lower zone involvement, smear and culture grade at baseline were significant parameters predisposing to an unfavorable TB treatment outcome in the univariate analysis. Reduction in radiological lesions in Chest X-ray by at least 50% at 2 months and 75% at the end of treatment helped in averting unfavorable responses. Smear and Culture conversion at the end of 2 months was highly significant as a predictor (p<0.001). In the multivariate analysis, the adjusted hazards ratios (HR) for an unfavorable response to TB therapy for extent of involvement, baseline cavitation and persistence (post treatment) were 1.21 (95% CI: 1.01-1.44), 1.73 (95% CI: 1.05-2.84) and 2.68 (95% CI: 1.4-5.12) respectively. A 3+ smear had an HR of 1.94 (95% CI: 0.81-4.64). Further probing into the interaction, among patients with 3+ and 2+ smears, HRs for cavitation were 3.26 (95% CI: 1.33-8.00) and 1.92 (95% CI: 0.80-4.60) while for >2 zones, were 3.05 (95% CI: 1.12-8.23) and 1.92 (95% CI: 0.72-5.08) respectively. Patients without cavitation, zonal involvement <2, and a smear grade less than 2+ had a better prognosis and constituted minimal disease. CONCLUSION: Baseline Cavitation, Opacities occupying >2 zones and 3+ smear grade individually and independently forecasted a poorer TB outcome. The interaction model revealed that Zonal involvement confined to 2 zones, without a cavity and smear grade up to 2+, constituting "minimal disease", had a better prognosis. Radiological clearance >50% along with smear conversion at the end of intensive phase of treatment, observed to be a reasonable alternative to culture conversion in predicting a successful outcome. These parameters may potentially take up key positions as stratification factors for future trials contemplating on shorter TB regimens.

Cost-Effective, Integrated In Vitro Phantoms for Cardiac MRI.

To provide lab scale in vitro phantom solutions for cardiac MR (CMR) studies that can be used for imaging structure and function as well as calorimetric measurements. The phantoms were purposed to accept user inputs such as beats per minute (BPM) and flow rate. We developed two generations of phantoms. The first phantom was developed using poly vinyl alcohol driven by a mechanical setup. The second was a 3D-printed phantom controlled through a user interface (UI) and a peristaltic pump. These phantoms were scanned for the characteristics mentioned above, which were qualitatively and quantitatively assessed through postprocessing of CMR images and compared with in vivo data.

Microleakage patterns of glass ionomer cement at cement-band and cement-enamel interfaces in primary teeth.

CONTEXT: In-vitro studies of microleakage are an initial screening method to assess the maximum theoretical loss of sealing ability in-vivo. AIMS: Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC) and resin-modified GIC (RMGIC) for band cementation. METHODS: Forty caries-free second primary molars were randomly divided into two groups of 20 teeth each. Preformed molar bands in the two groups were cemented to enamel with one of two types of cement: Conventional GIC (Fuji I, GC Corporation; Tokyo, Japan) and RMGIC (Fuji Plus, GC Corporation; Tokyo, Japan). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces. STATISTICAL ANALYSIS USED: Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The mean microleakage value for conventional GIC (Fuji I) at cement-band and cement-enamel interfaces was 2.41 mm and 2.15 mm, respectively. The mean microleakage value for RMGIC (Fuji Plus) at cement-band and cement-enamel interfaces was 0.44 mm and 0.46 mm, respectively. Compared to conventional GIC, RMGIC showed less microleakage at both cement-band and cement-enamel interfaces. P < 0.001 and it was statistically highly significant. CONCLUSIONS: Bands cemented with RMGIC had significantly less microleakage between the cement-band and cement-enamel interfaces than conventional GIC.

Rapid Prototyping of Two-Dimensional Non-Cartesian K-Space Trajectories (ROCKET) Using Pulseq and Graphical Programming Interface.

Magnetic resonance imaging is a well-established method for diagnostics and/or prognostics of various pathological conditions. Cartesian k-space trajectory-based acquisition is the popular choice in clinical magnetic resonance imaging, owing to its simple acquisition, reconstruction schemes, and well-understood artifacts. However, non-Cartesian trajectories are relatively more time efficient, with involved methods for image reconstruction. In this review, we survey non-Cartesian trajectories from the standpoint of rapid prototyping and/or implementation. We provide examples of two-dimensional (2D) and 3D non-Cartesian k-space trajectories with analytical equations, merits, limitations, and applications. We also demonstrate implementation of three variants of the 2D radial and spiral trajectories (standard, golden angle, and tiny golden angle), using open-source software. For rapid prototyping, pulse sequences were designed with the help of Pulseq. In-vitro phantom and in-vivo brain data were acquired with three variants of radial and spiral trajectories. The obtained raw data were reconstructed using a graphical programming interface. The signal-to-noise ratios of each of these reconstructions were quantified and assessed.

Multiband fMRI as a plausible, time-saving technique for resting-state data acquisition: Study on functional connectivity mapping using graph theoretical measures.

BACKGROUND AND OBJECTIVES: Ensuring patient comfort and compliance by emphasizing reduced time frame for image acquisition, without compromising image quality is the key aspect with functional MRI examination. Multiband resting state fMRI (MB-rsfMRI) is a fairly new technique that potentially shortens MR image acquisition time by providing increased number of time points. The study aims to compare signal characteristics as well as the functional connectivity using conventional resting-state fMRI (rsfMRI) with that of MB-rsfMRI technique. MATERIALS AND METHODS: 9 healthy volunteers have prospectively undergone conventional resting-state fMRI and Multiband rsfMRI scanning technique in a 3T GE scanner (Discovery MR750w™). We compared the temporal SNR (tSNR) of conventional rs-fMRI with that of MB-rsfMRI. We looked at the language network connectivity and small world network characteristics from graph theoretical measures to compare the two techniques. RESULTS: We computed the tSNR of conventional resting-state fMRI (rsfMRI) and MB-rsfMRI technique. A strong positive correlation was seen between graph theoretical measures from MB-rsfMRI and conventional rsfMRI (Pearson Correlation, r = 0.99). Both techniques showed similar small world network characteristics in healthy controls. CONCLUSION: The present study demonstrates negligible differences between the conventional-rsfMRI and MB-rsfMRI acquisitions on the computed graph theoretic measures. Accordingly current analysis proves that MB-rs-fMRI may be used as a time reducing acquisition technique that enables mapping of functional connectivity with similar outcome as conventional rs-fMRI in healthy subjects.

Pulseq-Graphical Programming Interface: Open source visual environment for prototyping pulse sequences and integrated magnetic resonance imaging algorithm development.

PURPOSE: To provide a single open-source platform for comprehensive MR algorithm development inclusive of simulations, pulse sequence design and deployment, reconstruction, and image analysis. METHODS: We integrated the "Pulseq" platform for vendor-independent pulse programming with Graphical Programming Interface (GPI), a scientific development environment based on Python. Our integrated platform, Pulseq-GPI, permits sequences to be defined visually and exported to the Pulseq file format for execution on an MR scanner. For comparison, Pulseq files using either MATLAB only ("MATLAB-Pulseq") or Python only ("Python-Pulseq") were generated. We demonstrated three fundamental sequences on a 1.5 T scanner. Execution times of the three variants of implementation were compared on two operating systems. RESULTS: In vitro phantom images indicate equivalence with the vendor supplied implementations and MATLAB-Pulseq. The examples demonstrated in this work illustrate the unifying capability of Pulseq-GPI. The execution times of all the three implementations were fast (a few seconds). The software is capable of user-interface based development and/or command line programming. CONCLUSION: The tool demonstrated here, Pulseq-GPI, integrates the open-source simulation, reconstruction and analysis capabilities of GPI Lab with the pulse sequence design and deployment features of Pulseq. Current and future work includes providing an ISMRMRD interface and incorporating Specific Absorption Ratio and Peripheral Nerve Stimulation computations.

Assessment of Coronal Leakage with Two Intracanal Medicaments After Exposure to Human Saliva-An In Vitro Study.

INTRODUCTION: One among the various reasons for root canal failure in endodontics is the leakage of an intracanal medicament due to improper coronal sealing. AIM: To assess the coronal leakage of two intracanal medicaments sealed with two different temporary filling materials. MATERIALS AND METHODS: An in-vitro study was done on 55 teeth where they were divided into three groups with two root canal medicaments namely calcium hydroxide + 0.2% chlorhexidine solution, triple antibiotic paste, and a control group. These three groups were restored temporarily with MD Temp and IRM, and these samples were checked for coronal leakage after 30 days. RESULTS: The group, triple antibiotic paste with IRM stayed for more number of days without leakage with the mean of 24.5 days, followed by group triple antibiotic paste with MD Temp. The least coronal leakage was seen in group MD Temp without Intracanal medicament with the mean of eight and half days followed by group IRM without Intracanal medicament. When comparing the two temporary filling materials without any medicament, there was no significant difference between the same. When comparing within MD Temp group, the least microleakage was seen with Triple antibiotic paste with MD Temp. In the IRM group, the least microleakage was seen with Triple antibiotic paste with IRM. CONCLUSION: Triple antibiotic paste was found to be the most promising intracanal medicament with an appropriate seal. CLINICAL SIGNIFICANCE: The best intracanal medicament, which is triple antibiotic paste in the present study could prevent microorganism leakage and inhibit bacterial growth.How to cite this article: Balaji S, Kumar K, Venkatesan R, Krishnamoorthy S, Manoharan V, Marimuthu S. Assessment of Coronal Leakage with Two Intracanal Medicaments After Exposure to Human Saliva-An In Vitro Study. Int J Clin Pediatr Dent., 2018;11(5):406-411.

Psychosocial Effects of Fractured Anterior Teeth among Rural Children.

AIM: The aim of the study is to determine how rural children view children with visible incisor fracture. MATERIALS AND METHODS: Class 7 (aged 11-12 years) and class 10 (aged 14-15 years) schoolchildren (the participants) were invited to make a social judgment about the color photograph of two children (the subjects). Participants were randomly allocated either (i) pictures of children without incisor fracture or (ii) pictures of the same children whose photographs had been digitally modified to visible incisor fracture. Using a child-centered questionnaire, participants rated subjects using a four-point Likert scale for three negative and six positive attributes. Total attribute scores were tested for significant differences, according to whether the subject had visible incisor fracture or not, using multivariate analysis of variance (p < 0.05). RESULTS: Both class 7 and 10 children rated subjects with visible incisor fracture more negatively than the subjects without incisor fracture. Female participants of class 10 have rated the male subject with incisor fracture significantly negatively (p < 0.01) than male subject without incisor fracture. How to cite this article: Venkatesan R, Naveen M, Teja R, Paulindraraj S, Vallabhaneni SK, Arumugam SB. Psychosocial Effects of Fractured Anterior Teeth among Rural Children. Int J Clin Pediatr Dent 2016;9(2):128-130.

Compressed sensing MRI: a review.

Compressed sensing (CS) is a mathematical framework that reconstructs data from highly undersampled measurements. To gain acceleration in acquisition time, CS has been applied to MRI and has been demonstrated on diverse MRI methods. This review discusses the important requirements to qualify MRI to become an optimal application of CS, namely, sparsity, pseudo-random undersampling, and nonlinear reconstruction. By utilizing concepts of transform sparsity and compression, CS allows acquisition of only the important coefficients of the signal during the acquisition. A priori knowledge of MR images specifically related to transform sparsity is required for the application of CS. In this paper, Section I introduces the fundamentals of CS and the idea of CS as applied to MRI. The requirements for application of CS to MRI is discussed in Section II, while the various acquisition techniques, reconstruction techniques, the advantages of combining CS and parallel imaging, and sampling mask design problems are discussed in Section III. Numerous applications of CS in MRI due to its ability to improve imaging speed are reviewed in section IV. Clinical evaluations of some of the CS applications recently published are discussed in Section V. Section VI provides information on available open source software that could be used for CS implementations.

Volumetric fat-water separated T2-weighted MRI.

BACKGROUND: Pediatric body MRI exams often cover multiple body parts, making the development of broadly applicable protocols and obtaining uniform fat suppression a challenge. Volumetric T2 imaging with Dixon-type fat-water separation might address this challenge, but it is a lengthy process. OBJECTIVE: We develop and evaluate a faster two-echo approach to volumetric T2 imaging with fat-water separation. MATERIALS AND METHODS: A volumetric spin-echo sequence was modified to include a second shifted echo so two image sets are acquired. A region-growing reconstruction approach was developed to decompose separate water and fat images. Twenty-six children were recruited with IRB approval and informed consent. Fat-suppression quality was graded by two pediatric radiologists and compared against conventional fat-suppressed fast spin-echo T2-W images. Additionally, the value of in- and opposed-phase images was evaluated. RESULTS: Fat suppression on volumetric images had high quality in 96% of cases (95% confidence interval of 80-100%) and were preferred over or considered equivalent to conventional two-dimensional fat-suppressed FSE T2 imaging in 96% of cases (95% confidence interval of 78-100%). In- and opposed-phase images had definite value in 12% of cases. CONCLUSION: Volumetric fat-water separated T2-weighted MRI is feasible and is likely to yield improved fat suppression over conventional fat-suppressed T2-weighted imaging.

ANTHEM: anatomically tailored hexagonal MRI.

PURPOSE: This study aimed to investigate the use of anatomically tailored hexagonal sampling for scan-time and error reduction in MRI. MATERIALS AND METHODS: Anatomically tailored hexagonal MRI (ANTHEM), a method that combines hexagonal sampling with specific symmetry in anatomical geometry, is proposed. By using hexagonal sampling, aliasing artifacts are moved to regions where, due to the nature of the anatomy, aliasing is inconsequential. This can be used to either reduce scan time while maintaining spatial resolution or reduce residual errors in speedup techniques like UNFOLD and k-t BLAST/SENSE, which undersample k-space and unwrap fold-over artifacts during reconstruction. Computer simulations as well as phantom and volunteer studies were used to validate the theory. A simplified reconstruction algorithm for hexagonally sampled and subsampled k-space data was also used. RESULTS: A reduction in sampling density of 13.4% and 25% in each hexagonally sampled dimension was achieved for spherical and conical geometries without aliasing or reduction in spatial resolution. Optimal subsampling schemes that can be utilized by UNFOLD and k-t BLAST/SENSE were derived using hexagonal subsampling, which resulted in maximal, isotropic dispersal of the aliases. In combination with UNFOLD, ANTHEM was shown to move residual aliasing artifacts to the corners of the field of view, yielding reduced artifacts in CINE reconstructions. CONCLUSIONS: ANTHEM was successful in reducing acquisition time in conventional MRI and in reducing errors in UNFOLD imaging.

Diffusion-weighted EPI with magnetization transfer contrast.

Capabilities of diffusion-weighted (DW) and magnetization transfer (MT) imaging are well established for tissue characterization in various pathologies individually. However, the effect of suppression of macromolecules on applying MT pulse on signals associated with DW imaging and resulting change in the apparent diffusion coefficient (ADC) of water molecules has not been demonstrated previously. In the present study, we have performed DW echo planar imaging (EPI) with and without MT preparation pulse to see the effect of macromolecular signal suppression on ADC. A total of 10 normal volunteers and 20 patients with different intracranial cystic lesions [abscesses (n=10), cystic tumors (n=5), arachnoid cysts (n=5)] were subjected to DW imaging (b=0 and 1000 s/mm(2)) with and without MT saturation pulse. Analysis of region of interest (ROI) from different areas of white matter in normal volunteers and in the wall and cavity of cystic lesions in patients was carried out for calculating the ADC values. We found a significant increase (P<.05) in the ADC values in brain parenchyma and cavity of those intracranial cystic lesions having considerable amount of proteins after the application of MT preparation pulse except for arachnoid cysts. This is due to the size of the macromolecules present in the normal and abnormal tissue. Our studies suggest that this technique is likely to give a novel image contrast and may be of value in improving the tissue specificity in pathologies associated with variable macromolecular size.