Spectral trimming technique: a new approach for suppressing motion artefacts in stress electrocardiography.

Motion artefacts in electrocardiographic (ECG) signal are suppressed mainly by adaptive noise cancellation and wavelet denoising. While the former requires a motion sensor in addition to ECG electrodes, the latter removes some of the desired low-frequency components in the signal. In this paper spectral trimming technique is being introduced for suppressing the motion artefacts in stress electrocardiography. In this method, Fourier spectral coefficients up to 1.221 Hz of noisy signal are trimmed on the basis of template derived from resting ECG signal in the same subject. The proposed spectral trimming technique has yielded the lowest value of mean ± standard deviation for root mean square error (18.92 ± 8.71) and highest value of the signal to noise ratio (6.439 ± 4.266) as compared to other three methods, namely adaptive noise cancellation, wavelet decomposition and adaptive line enhancement with compatible value of correlation coefficient. Subsequently, spectral trimming technique has been implemented in real-time (deferred by 8.2 s) application for stress electrocardiography. Spectral trimming technique thus offers a method of choice for motion artefact suppression in offline as well as deferred online applications. This method takes care of the limitations of conventional methods such as adaptive noise cancellation or wavelet denoising for suppressing motion artefacts in stress electrocardiography.

A Critical Assessment of the Golden Hour and the Impact of Procedural Timing in Stroke Thrombectomy.

BACKGROUND AND PURPOSE: Previous studies in acute ischemic stroke have demonstrated the importance of minimizing delays to endovascular treatment and keeping thrombectomy procedural times at <30-60 minutes. The purpose of this study was to investigate the impact of thrombectomy procedural times on clinical outcomes. MATERIALS AND METHODS: We retrospectively compared 319 patients having undergone thrombectomy according to procedural time (<30 minutes, 30-60 minutes, and >60 minutes) and time from stroke onset to endovascular therapy (≤6 or >6 hours). Clinical characteristics of patients with postprocedural intracranial hemorrhage were also assessed. Logistic regression was used to determine independent predictors of poor outcome at 90 days (mRS ≥3). RESULTS: Greater age (OR, 1.03; 95% CI, 1.01-1.06; P = .016), higher admission NIHSS score (OR, 1.10; 95% CI, 1.04-1.16; P = .001), history of diabetes mellitus (OR, 1.96; 95% CI, 1.05-3.65; P = .034), and postprocedural intracranial hemorrhage were independently associated with greater odds of poor outcome. Modified TICI scale scores of 2c (OR, 0.11; 95% CI, 0.04-0.28; P < .001) and 3 (OR, 0.15; 95% CI, 0.06-0.38; P < .001) were associated with reduced odds of poor outcome. Although not statistically significant on univariate analysis, onset to endovascular therapy of >6 hours was independently associated with increased odds of poor outcome (OR, 2.20; 95% CI, 1.11-4.36; P = .024) in the final multivariate model (area under the curve = 0.820). Procedural time was not independently associated with clinical outcome in the final multivariate model (P > .05). CONCLUSIONS: Thrombectomy procedural times beyond 60 minutes are associated with lower revascularization rates and worse 90-day outcomes. Procedural time itself was not an independent predictor of outcome. While stroke thrombectomy procedures should be performed rapidly, our study emphasizes the significance of achieving revascularization despite the requisite procedural time. However, the potential for revascularization must be weighed against the risks associated with multiple thrombectomy attempts.

Development of a miniature and ASIC based impedance cardiograph.

In view of cardiac output monitoring application of impedance cardiography a miniature impedance cardiograph has been developed, which is based on an application specific integrated circuit (analog front end chip AFE4300). Carrier current capability of this chip has been enhanced four times (up to 3.2 milliamperes) for cardiology applications with the help of an external resistance, not provisioned in the original design. Also the sensed signal is externally amplified before feeding to AFE chip to increase resolution in the impedance range of 10-50 Ohms.The AFE chip is interfaced to a Personal Computer with the help of a microcontroller board through a USB cable. Application software programs the AFE chip for sending a carrier current of 3.2 milliamperes (peak to peak) to the subject's body segment through current output ports and sensing the chest impedance through voltage input ports. The chest impedance is read in detector mode and communicated to Laptop through serial peripheral interface of the chip. Chest impedance, change in impedance as a function of time and rate of change of impedance are displayed on the graphic user interface. Fifteen minute data from volunteers have shown consistent recordings, as described in this paper.

Pipeline Diameter Significantly Impacts the Long-Term Fate of Jailed Side Branches during Treatment of Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Although covered side branches typically remain patent acutely following Pipeline Embolization Device embolization of intracranial aneurysms, the long-term fate of these vessels remains uncertain. We therefore elected to investigate factors that may influence the long-term patency of these covered side branches. MATERIALS AND METHODS: We retrospectively evaluated the long-term patency of side branches covered by the Pipeline Embolization Device at our institution during treatment of intracranial aneurysms with at least 6 months of conventional angiography follow-up. Procedural and anatomic factors that might influence the fate of covered side branches were explored. RESULTS: One hundred forty-eight Pipeline Embolization Device treatments in 137 patients met the inclusion criteria. In 217 covered side branches, 29 (13.4%) were occluded on follow-up, and 40 (18.4%) were stenotic. All stenoses and occlusions were asymptomatic. In the entire cohort and in the largest subset of ophthalmic arteries, a smaller Pipeline Embolization Device diameter was associated with branch vessel occlusion (P = .001, P = .013). When we considered stenotic and occluded side branches together, smaller Pipeline Embolization Device size (P = .029) and administration of intraprocedural abciximab (P = .03) predicted side branch stenosis/occlusion, while anterior choroidal branch type (P = .003) was a predictor of gross side branch patency. CONCLUSIONS: A smaller Pipeline Embolization Device diameter is associated with delayed side branch stenosis/occlusion following Pipeline Embolization Device treatment, likely due to the higher metal density of smaller caliber devices. Although hemodynamic factors, including the potential for collateral flow, are still paramount in determining the fate of covered side branches, the amount of metal coverage at the side branch orifice also plays an important role.

Harmonic analysis of peripheral pulse for screening subjects at high risk of diabetes.

Power spectral density (PSD) of peripheral pulses in human has been investigated in the past for its clinical applications. Continuing the efforts, data acquired using Peripheral Pulse Analyser in research projects sponsored by Board of Research in Nuclear Sciences in 207 control subjects, 18 descendants of diabetic patients and 22 patients with systemic hypertension have been subjected to PSD analysis for its study of harmonics. Application software, named Pulse Harmonic Analyser specifically developed for this work, selected 131,072 samples from each data file, obtained PSD, derived 52 PHA parameters and saved them in an Excel sheet. Coefficient of variation in control data was reduced significantly by application of Central Limit Theorem, which enabled use of parametric methods for statistical analysis of the observations. Data in hypertensive patients have shown significant difference in comparison to that of controls in eight parameters at low values of α and ß. Data in offspring of diabetic patients also have shown significant difference in one parameter indicating its usefulness in screening subjects with genetic disposition of acquiring Type-II Diabetes. PHA analysis has also yielded sub-harmonic components, which are related to combined variability in the heart rate, pulse volume and pulse morphology and has a potential to become method of choice for real time variability monitoring.

The Efficacy of Shielding Systems for Reducing Operator Exposure during Neurointerventional Procedures: A Real-World Prospective Study.

BACKGROUND AND PURPOSE: Neurointerventional surgery may expose patients and physician operators to substantial amounts of ionizing radiation. Although strategies for reducing patient exposure have been explored in the medical literature, there has been relatively little published in regards to decreasing operator exposure. The purpose of this study was to evaluate the efficacy of shielding systems in reducing physician exposure in a modern neurointerventional practice. MATERIALS AND METHODS: Informed consent was obtained from operators for this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study. Operator radiation exposure was prospectively measured during 60 consecutive neurointerventional procedures from October to November 2013 using a 3-part lead shielding system. Exposure was then evaluated without lead shielding in a second 60-procedure block from April to May 2014. A radiation protection drape was randomly selected for use in half of the cases in each block. Two-way analysis of covariance was performed to test the effect of shielding systems on operator exposure while controlling for other covariates, including procedure dose-area product. RESULTS: Mean operator procedure dose was 20.6 µSv for the entire cohort and 17.7 µSv when using some type of shielding. Operator exposure significantly correlated with procedure dose-area product, but not with other covariates. After we adjusted for procedure dose-area product, the use of lead shielding or a radiation protection drape significantly reduced operator exposure by 45% (F = 12.54, P < .0001) and 29% (F = 7.02, P = .009), respectively. The difference in protection afforded by these systems was not statistically significant (P = .46), and their adjunctive use did not provide additional protection. CONCLUSIONS: Extensive lead shielding should be used as much as possible in neurointerventional surgery to reduce operator radiation exposure to acceptable levels. A radiation protection drape is a reasonable alternative when standard lead shielding is unavailable or impractical to use without neglecting strategies to minimize the dose.

Sclerosing mesenteric panniculitis in a young patient : common cause of diagnostic dilemma and treatment refractoriness.

BACKGROUND: Sclerosing mesenteric panniculitis (SMP) is an idiopathic chronic fibroinflammatory disorder of the intra-abdominal fat. CASE PRESENTATION: Herin, we report a case of SMP, involving the omentum, mesentery and peri-colic fat in a 18 year old male, who presented with significant and recurrent abdominal distension for 4.5 years. Computed tomogram revealed ascites, with nodular and irregular omental thickening and foci of calcification. Non-specific radiological and histological features made an accurate diagnosis extremely difficult. After a thorough work up and exclusion of other differentials, diagnosis of a nodular SMP (Weber Christian disease) was given. After showing resistance to chemotherapeutic agents, slow response was noted with cyclophosphamide, followed by rapid symptomatic improvement with mesenterectomy. CONCLUSION: SMP is an uncommon benign mesenteric/ omental inflammation, and is a diagnosis of exclusion. As treatment refractoriness is common, management should be individualized and continued for along period. Surgical omentectomy may be helpful.

Attitudes and Awareness Regarding Hepatitis B and Hepatitis C Amongst Health-care Workers of a Tertiary Hospital in India.

BACKGROUND: Hepatitis is an inflammatory disease of the liver. In sever cases, it may lead to permanent liver damage including liver cirrhosis or hepato-cellular carcinoma and may ultimately lead to death. Health-care workers (HCWs), due to their regular contact with patients are at a high-risk of acquiring this disease. AIM: The aim of this study was to assess the knowledge and attitude toward hepatitis B and C infection among the health-care interns and correlate the level of awareness to the attitude they behold toward the disease. SUBJECTS AND METHODS: A closed ended questionnaire consisting of questions to evaluate the knowledge regarding hepatitis B and C infection and attitude of the (HCWs/interns) was duly filled by 255 participants including, 100 dental, 100 medical, and 55 nursing interns. Statistical analysis was carried out using the Chi-square test, ANOVA test, post-hoc test and Pearson's correlation. RESULTS: Although most of the interns were aware of the existence of hepatitis B and C infection, the level of awareness regarding the modes of transmission and vaccination was found to be dissatisfactory. Awareness level regarding the infection among nursing interns was statistically significantly lower than the dental and medical interns. A direct positive correlation as found between awareness score and behavior score, which reveals that interns with better awareness level had better attitudes toward the infection and prevention of its transmission. CONCLUSION: There is an urgent need to increase the level and quality of training among HCWs to prevent the spread of hepatitis B virus and hepatitis C virus.

A comparative evaluation of probiotics on salivary mutans streptococci counts in Indian children.

AIM: Probiotics and their effect on oral health have been a focus of numerous trials in recent times. No documented trials have been reported from developing countries such as India with its focus on probiotic use, especially in the paediatric population. The aim of this study is to evaluate the effect of probiotics on salivary mutans streptococci (MS) counts of children using the two commercially and widely available preparations and to explore their anti-caries potential. STUDY DESIGN: A placebo controlled study was undertaken with 3 parallel arms comprising a total of 150 healthy children (7-14 years). The subjects were randomly divided into the groups (each comprising 50 children): group A - placebo powder, Group B - a freeze dried powdered combination of Lactobacillus rhamnosus and Bifidobacterium species, Group C - a freeze dried powdered preparation of Bacillus coagulans. The subjects were instructed to mix the preparation in 20 ml of water and to follow a swish and swallow method for 14 days. Mutans streptococci colony counts per ml of saliva were performed on Mitis-Salivarius Bacitracin agar collected on the first day and 14 days post-intervention. RESULTS: A statistically significant reduction (p<0.001) in salivary mutans streptococci counts was recorded in both groups B and C after 14 days of probiotic ingestion. CONCLUSION: A cost-effective probiotic such as Bacillus coagulans might be a subject for further research for prevention of caries in children.

Single prediction equation for bioelectrical impedance analysis in adults aged 22-59 years.

The purpose of this study was to validate a single bioelectrical impedance analysis (BIA) equation in healthy Indian subjects aged 22-59 years with a body mass index (BMI) between 16.8 and 47.3 kg m⁻². Healthy subjects (34 men and 30 women) were measured by two methods: bone mineral content (BMC) was measured by a commercial body composition analyser and bioelectrical impedance at various frequencies was measured by a newly developed bioelectrical impedance measurement system. As correlations were high and prediction error was low, a single equation was developed using all subjects as follows: BMC = -3.5268 + (0.0279  x  h) + (0.0145  x  w) + (184  x  (h²/Z(body50)))-(1.08  x  (w x  h²/Z(body6.25)))-(0.0032  x  (age))-(0.103  x  (sex); men = 1, women = 0). BMC measured from commercial instrument InBody720 was 2.552 ±â€Š0.457 kg. BMC predicted by equation was 2.554 ±â€Š0.447 kg (R = 0.976, adjusted R²â€Š= 0.948, standard error of estimate = 0.104 kg, total error = 0.09987 kg). The results of this study show that the newly developed multi-frequency bioelectrical impedance measurement system with the single prediction BIA equation can be used in screening the subjects suspected with osteoporosis and for follow-up study of the patient under the therapy for osteoporosis. For validation of commercial instrument InBody720, BMC of 22 healthy subjects was measured by InBody720 and dual-energy X-ray absorptiometry. High correlation (R = 0.9531) and low error (total error = 0.0913 kg) was found between these two methods.

Application of crisp and fuzzy clustering algorithms for identification of hidden patterns from plethysmographic observations on the radial pulse.

Radial Pulse forms the most basic and essential physical sign in clinical medicine. The paper proposes the application of crisp and fuzzy clustering algorithms under supervised and unsupervised learning scenarios for identifying non-trivial regularities and relationships of the radial pulse patterns obtained by using the Impedance Plethysmographic technique. The objective of our paper is to unearth the hidden patterns to capture the physiological variabilities from the arterial pulse for clinical analysis, thus providing a very useful tool for disease characterization. A variety of fuzzy algorithms including Gustafson-Kessel (GK) and Gath-Geva (GG)have been intensively tested over a diverse group of subjects and over 4855 data sets. Exhaustive testing over the data set show that about 80 % of the patterns are successfully classified thus providing promising results. A Rank Index of 0.7739 is obtained under supervised learning, which provides an excellent conformity of our process with the results of plethysmographic experts. A correlation of the patterns with the diseases of heart, liver and lungs is judiciously performed.

Clinical validation of software for a versatile variability analyzer: Assessment of autonomic function.

Study of physiological variability is an upcoming area of research having manifold clinical applications. Considerable work has been done on heart rate variability and blood pressure variability during the past four decades. Electronics division, Bhabha Atomic Research Centre, has developed an instrument called medical analyzer, which can be used to study several variabilities simultaneously. This instrument has been used to collect data from control subjects and patients with established diagnosis. The data has been analyzed with the help of a software package developed for this purpose and has been found to be consistent with expected manifestations of the disease on the autonomic nervous system. The description of the software package and results of the study are briefly described in this paper.

Corrected formula for estimating peripheral blood flow by impedance plethysmography.

In this paper, the limitations of the conventional formula for the computation of peripheral blood flow from impedance plethysmograms are highlighted, and a correction to the formula is suggested. A conductivity cell experiment is described to show the dependence of the value of the blood flow index (BFI), obtained from the conventional formula, on the mean resistivity of the cell. It is also shown that the value of the corrected BFI is independent of the mean resistivity. Anomalies observed in the amplitude of systolic waves in impedance plethysmograms of patients with oedema are explained.

Impedance plethysmography of thoracic region: impedance cardiography.

Impedance plethysmograms were recorded from thoracic region in 254 normal subjects, 183 patients with coronary artery disease, 391 patients with valvular heart disease and 107 patients with congenital septal disorder. The data in 18 normal subjects and 55 patients showed that basal impedance decreases markedly during exercise in patients with ischaemic heart disease. Estimation of cardiac index by this technique in a group of 99 normal subjects has been observed to be more consistent than that of the stroke volume. Estimation of systolic time index from impedance plethysmograms in 34 normal subjects has been shown to be as reliable as that from electrocardiogram, phonocardiogram and carotid pulse tracing. Changes in the shape of plethysmographic waveform produced by valvular and congenital heart diseases are briefly described and the role of this technique in screening cardiac patients has been highlighted.

Effect of pulmonary circulation on vector impedance cardiogram.

Vector impedance cardiograms in horizontal lead configuration [VICG(H)] were recorded in 34 normal subjects, 18 patients with mitral stenosis, 9 patients with mitral regurgitation, 14 patients with aortic regurgitation and 13 patients with non- cyanotic septal disorders. Data in normal subjects revealed that most of the phase reversal points in VICG(H) waveform did not coincide with those of conventional impedance cardiogram. The shape of VICG(H) waveform and values of VICG indices were observed to be markedly affected in patients having significant alteration in the pulmonary circulation and the changes observed were specific of the type of the disorder. The results of the study suggested that right side of the heart had dominant contribution in generation of VICG(H) waveform.

Evaluation of state of circulation in radiation injury using impedance plethysmography.

Seven patients with history of radiation burn were subjected to impedance plethysmographic investigation at Non-invasive Vascular Laboratory, K. E. M. Hospital. Impedance plethysmograms were recorded from various locations in both the upper extremities in supine and digits of both the hands in supine as well as on hyper-abduction in sitting position. Control values of blood flow index (BFI) and differential pulse arrival time (DPAT) were derived from similar data in 15 normal subjects. It was observed that digits having thinning of epidermis of skin recorded marked decrease in values of BFI and significant change in value of DPAT and these observations correlated well with thermography and vascular scintigraphy. Digits recording significant decrease in BFI, which were clinically normal, were found to have changes in the skin during follow up examination. Thus IPG provided a sensitive modality for detecting ischaemia in early stages in patients with history of radiation injury.

Diagnosis of peripheral arterial occlusive diseases using impedance plethysmography.

Impedance plethysmographic observations have been compared with arteriographic findings in 216 patients with peripheral arterial occlusive diseases. Impedance plethysmographic diagnosis in these patients was obtained by Parulkar's method without apriori knowledge of arteriographic diagnosis. But for minor discrepancy in the anatomical location of the block in few patients, impedance plethysmographic observations correlated very well with arteriographic findings. Impedance plethysmographic diagnosis was found to be correct in 312, wrong in 53, false negative in 8 limbs respectively, yielding a sensitivity of 97.5% and specificity of 98.1% of this technique.

Impedance plethysmographic observations in thoracic outlet syndrome.

Forty patients with symptoms of neuro-vascular compression in the upper extremities were subjected to impedance plethysmographic study using Parulkar's method. Two patients recorded decreased blood flow (BFI) in supine position and were diagnosed as having partial occlusion at subclavian level. Sixteen of the patients recorded decreased BFI on 90 degrees abduction and hyper-abduction. Twelve of these patients had radiological evidence of anomalous cervicle ribs. In remaining four patients extrinsic impression on the subclavian artery due to fibrous deposits was confirmed by arteriography. Remaining 22 patients recorded normal impedance plethysmograms. Impedance plethysmography thus provided a non-invasive modality for confirmation of vascular compression in thoracic outlet syndrome.

Diagnosis of venous disorders using impedance plethysmography.

Impedance plethysmography (IPG) was carried out in one hundred and forty-one patients suspected of venous disorders using Parulkar's method. In these patients occlusive impedance phlebography (OIP) and venography were also carried out using standard procedures. Comparison of IPG and OIP observations with venographic findings revealed sensitivity of these methods to be 65% and 77.7% in the diagnosis of primary varicosity of veins and chronic deep vein thrombosis respectively with a specificity of 85%. Occlusive impedance phlebograms showing unilateral decrease in OIP parameters were observed to be sufficiently diagnostic. IPG observations in 5 patients with arterio-venous malformation were observed to be different from those in patients with deep vein thrombosis.