Evaluation of moisture-related attenuation coefficient and water diffusion velocity in human skin using optical coherence tomography.

In this study, time-resolved optical coherence tomography (OCT) scanning images of the process of water diffusion in the skin that illustrate the enhancement in the backscattered intensities due to the increased water concentration are presented. In our experiments, the water concentration in the skin was increased by soaking the hand in water, and the same region of the skin was scanned and measured with the OCT system and a commercial moisture monitor every three minutes. To quantitatively analyze the moisture-related optical properties and the velocity of water diffusion in human skin, the attenuation coefficients of the skin, including the epidermis and dermis layers, were evaluated. Furthermore, the evaluated attenuation coefficients were compared with the measurements made using the commercial moisture monitor. The results demonstrate that the attenuation coefficient increases as the water concentration increases. Furthermore, by evaluating the positions of center-of mass of the backscattered intensities from OCT images, the diffusion velocity can be estimated. In contrast to the commercial moisture monitor, OCT can provide three-dimensional structural images of the skin and characterize its optical property, which together can be used to observe morphological changes and quantitatively evaluate the moisture-related attenuation coefficients in different skin layers.

Defect detection and property evaluation of indium tin oxide conducting glass using optical coherence tomography.

This study demonstrates a new approach for evaluating the properties of indium tin oxide (ITO) conducting glass and identifying defects using optical coherence tomography (OCT). A swept-source OCT system was implemented to scan the ITO conducting glass to enable two-dimensional or three-dimensional imaging. With OCT scanning, the defects can be clearly identified at various depths. Several parameters in addition to morphological information can be estimated simultaneously, including the thickness of the glass substrate, the refractive index, reflection coefficient, and transmission coefficient, all of which can be used to evaluate the quality of ITO conducting glass. This study developed a modified method for evaluating the refractive index of glass substrates without having to perform multiple scans as well as a segmentation algorithm to separate the interfaces. The results show the potential of OCT as an imaging tool for the inspection of defects in ITO conducting glass.

Therapeutic lung lavage with diluted surfactant in neonates with severe meconium aspiration syndrome.

Meconium aspiration syndrome (MAS) may result in considerable morbidity and mortality in newborn infants. The current standard treatment is still in need of improvement for the most severe patients. We report 3 cases with devastating MAS that was successfully treated with therapeutic lung lavage. These cases were all delivered in local obstetrics clinics or hospitals with meconium-stained amniotic fluid and non-vigorous appearance at birth. However, no endotracheal suction was performed when they were born. All of them suffered from severe hypoxia and unstable vital signs despite there being high ventilatory settings when they were transferred to the tertiary medical center. Therapeutic lung lavage with diluted surfactant (Survanta, 5 mg/mL, 30 mL/kg in 2 aliquots) was performed within 24 hours of age. Bloody fluid (about 40-50% of total lavage amount) was recovered in all 3 cases. Although brief desaturation and bradycardia were observed during the procedures, 2 of them tolerated the procedures well and improved soon after lavage. The other patient received lung lavage in a relatively unstable condition and needed chest tapping to relieve bilateral pleural effusion. Their respiratory condition improved after the procedures, and they were all discharged within 1 month without major respiratory complications. These successful experiences are compatible with previous animal studies and other case reports with different lavage protocols. We conclude that therapeutic lung lavage may improve the outcome in newborn infants with severe MAS, and there were no significant adverse side effects observed. Before performing lung lavage, stabilization and optimal support may prevent unexpected results during and after lavage.

Characteristics of Kawasaki disease in infants younger than six months of age.

BACKGROUND: Kawasaki disease is the leading cause of acquired heart disease in childhood. However, there are only a few reports in infants younger than 6 months. The objective of this study is to investigate the clinical and laboratory characteristics of Kawasaki disease in infants younger than 6 months. METHODS: From 1994 to 2003, 120 patients with Kawasaki disease diagnosed at our institution were included. Group 1 consisted of 20 (17%) patients younger than 6 months, and group 2 consisted of 100 (83%) patients older than 6 months. Clinical manifestations, laboratory results, echocardiographic findings, treatment and outcome were compared between these 2 groups. RESULTS: Clinical manifestations (hydrops of gallbladder: 0% versus 16%, P < 0.001) and laboratory results (white blood cell count 21,740 +/- 11,706 versus 11,830 +/- 4390/mm3, P < 0.001; hemoglobin 9.98 +/- 1.25 versus 10.8 +/- 1.37 g/dL, P = 0.015; platelet 483 +/- 393 versus 355 +/- 138 x 1000/mm3, P = 0.011; triglyceride 138 +/- 77.5 versus 107 +/- 17 mg/dL, P < 0.001) were different between patients with Kawasaki disease younger and older than 6 months, respectively. Younger infants were more likely to have incomplete presentation (35% versus 12%, P = 0.025), coronary involvement (65% versus 19%, P < 0.001), late intravenous immunoglobulin treatment and relatively poor outcome. CONCLUSIONS: Infants younger than 6 months with prolonged unexplained febrile illnesses should be suspected as having Kawasaki disease, despite the incomplete clinical presentation. Because early diagnosis and timely treatment are difficult in younger infants with Kawasaki disease because of delayed and incomplete clinical presentations, echocardiogram becomes an important implement for diagnosis. Early intravenous immunoglobulin treatment is required in view of the highest risk of coronary involvement in them.

Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode.

Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging.

An Efficient Interval Type-2 Fuzzy CMAC for Chaos Time-Series Prediction and Synchronization.

This paper aims to propose a more efficient control algorithm for chaos time-series prediction and synchronization. A novel type-2 fuzzy cerebellar model articulation controller (T2FCMAC) is proposed. In some special cases, this T2FCMAC can be reduced to an interval type-2 fuzzy neural network, a fuzzy neural network, and a fuzzy cerebellar model articulation controller (CMAC). So, this T2FCMAC is a more generalized network with better learning ability, thus, it is used for the chaos time-series prediction and synchronization. Moreover, this T2FCMAC realizes the un-normalized interval type-2 fuzzy logic system based on the structure of the CMAC. It can provide better capabilities for handling uncertainty and more design degree of freedom than traditional type-1 fuzzy CMAC. Unlike most of the interval type-2 fuzzy system, the type-reduction of T2FCMAC is bypassed due to the property of un-normalized interval type-2 fuzzy logic system. This causes T2FCMAC to have lower computational complexity and is more practical. For chaos time-series prediction and synchronization applications, the training architectures with corresponding convergence analyses and optimal learning rates based on Lyapunov stability approach are introduced. Finally, two illustrated examples are presented to demonstrate the performance of the proposed T2FCMAC.

Investigation of temporal vascular effects induced by focused ultrasound treatment with speckle-variance optical coherence tomography.

Focused ultrasound (FUS) can be used to locally and temporally enhance vascular permeability, improving the efficiency of drug delivery from the blood vessels into the surrounding tissue. However, it is difficult to evaluate in real time the effect induced by FUS and to noninvasively observe the permeability enhancement. In this study, speckle-variance optical coherence tomography (SVOCT) was implemented for the investigation of temporal effects on vessels induced by FUS treatment. With OCT scanning, the dynamic change in vessels during FUS exposure can be observed and studied. Moreover, the vascular effects induced by FUS treatment with and without the presence of microbubbles were investigated and quantitatively compared. Additionally, 2D and 3D speckle-variance images were used for quantitative observation of blood leakage from vessels due to the permeability enhancement caused by FUS, which could be an indicator that can be used to determine the influence of FUS power exposure. In conclusion, SVOCT can be a useful tool for monitoring FUS treatment in real time, facilitating the dynamic observation of temporal effects and helping to determine the optimal FUS power.

Noninvasive imaging of heart chamber in Drosophila with dual-beam optical coherence tomography.

The heart chamber of an adult Drosophila is approximately 2 mm long and 0.5 mm wide, and the interwall separation of different heart portions during systole and diastole range from tens of micrometers to hundreds of micrometers. Furthermore, the heart chamber has a curved structure, which results in the larger differences in depth between the different heart portions. However, applying the wavelength calibration process before Fourier transform in an optical coherence tomography (OCT) system may cause degradation in system sensitivity and longitudinal resolution when the optical path difference between the reference and sample arms increases, which makes imaging the entire heart chamber difficult with OCT system. Additionally, since the heartbeat rate of Drosophila is approximately 6 beats/s, a high-speed OCT system is necessary to record the dynamics of the heat beats. In this study, we propose a new approach to visualize the entire heart chamber including the conical chamber and four ostia portions, and to observe the retrograde and anterograde beats. A buffered Fourier-domain mode-locked (FDML) laser is implemented to provide a high imaging speed. Two output ports of the buffered FDML laser are used simultaneously to scan the different heart portions of Drosophila, and the effective A-scan rate of the OCT system can be doubled. Then, the two scanned images are merged into a single B-mode scan. Furthermore, with dual-beam OCT system, the beating behaviors of the different heart portions from 7-day-old and 21-day-old flies are compared.

Monitoring of wound healing process of human skin after fractional laser treatments with optical coherence tomography.

Fractional photothermolysis induced by non-ablative fractional lasers (NAFLs) or ablative fractional lasers (AFLs) can remodel the skin, regenerate collagen, and remove tumor tissue. However, fractional laser treatments may result in severe side effects, and multiple treatments are required to achieve the expected outcome. Thus, the treatment outcome and downtime after fractional laser treatments are key issues to determine the following treatment strategy. In this study, an optical coherence tomography (OCT) system was implemented for in vivo studies of wound healing after NAFL and AFL treatments. According to the OCT scanning results, the laser-induced photothermolysis including volatilization and coagulation could be morphologically identified. To continue monitoring the wound healing process, the treated regions were scanned with OCT at different time points, and the en-face images at various tissue depths were extracted from three-dimensional OCT images. Furthermore, to quantitatively evaluate the morphological changes at different tissue depths during wound healing, an algorithm was developed to distinguish the backscattering properties of untreated and treated tissues. The results showed that the coagulation damage induced by the NAFLs could be rapidly healed in 6 days. In contrast, the tissue volatilization induced by AFLs required a longer recovery time of 14 days. In conclusion, this study establishes the feasibility of this methodology as a means of clinically monitoring treatment outcomes and wound healing after fractional laser treatments.

Sudden and unexpected and near death during the early neonatal period: a multicenter study.

BACKGROUND: To investigate the incidence, clinical presentation and possible etiologies or risk factors of early onset of sudden and unexpected death or near-miss. METHODS: From 2001 to 2005, a retrospective analysis of observational database of neonates who were younger than one week old without any risk factors at five tertiary medical centers. The demographic data, clinical manifestations, laboratory data and possible etiologies were retrospectively collected and analyzed. RESULTS: Seventeen neonates presumed to be healthy at birth encountered early near death in five medical centers in Taipei city. The mean gestation age (GA) was 38.5 ± 1.2 weeks, mean birth body weight (BBW) was 2948.2 ± 327.8 gm. The median age at event was 26 hours old. Eleven patients were rooming-in babies with exclusive breast feeding. Seven patients (41.2%) died; seven patients (41.2%) survived with neurological sequelas, and the remaining three patients (17.6%) survived without complication. Possible causative factors included infection in two cases, urea cycle disorder in one case, hypertrophic cardiomyopathy in one case, hypocalcemia only in one case, hypocalcemia plus airway obstruction in one case, dehydration-related diseases in seven cases and unknown in 4 cases; there was no autopsy case. CONCLUSION: More effort on promotion of autopsy to discover the underlying disease is necessary and helpful. To build up an alarm system or protocol for education and early detection is the basis to prevent this tragedy.

Observations of cardiac beating behaviors of wild-type and mutant Drosophilae with optical coherence tomography.

Time-resolved optical coherence tomography (OCT) scanning images of wild-type and mutant fruit flies (Drosophila melanogaster), illustrating the heartbeat patterns for evaluating their cardiac functions, are demonstrated. Based on the heartbeat patterns, the beat rate and the relative phase between the first two heart segments can be evaluated. The OCT scanning results of mutant flies with impaired proteasome function in cardiac muscles show irregular heartbeat patterns and systematically decreased average beat rates, when compared with the regular patterns of ~4.97 beats/s in average beat rate of the wild-type. In both wild-type and proteasome mutant flies, the beatings at different locations in the same heart segment are essentially synchronized. However, between different heart segments, although the beating in the second segment shows a lag in phase behind that of the first segment in a wild-type, in a proteasome mutant, the beating in the second segment becomes significantly leading that of the first segment. Besides the comparison between the wild-type and proteasomal mutant flies, the influences of using different methods for immobilizing flies during OCT scanning on the heart functions are demonstrated.