Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography

Catheter/endoscope-based optical coherence tomography (OCT) is a powerful modality that visualizes structural information in luminal organs. Increases in OCT speed have reduced motion artifacts by enabling acquisition faster than or comparable to the time scales of physiological motion. However motion distortion remains a challenge because catheter/endoscope OCT imaging involves both circumferential and longitudinal scanning of tissue. This paper presents a novel image processing method to estimate and correct motion distortion in both the circumferential and longitudinal directions using a single en face image from a volumetric data set. The circumferential motion distortion is estimated and corrected using the en face image. Then longitudinal motion distortion is estimated and corrected using diversity of image features along the catheter pullback direction. Finally, the OCT volume is resampled and motion corrected. Results are presented on synthetic images and clinical OCT images of the human esophagus.     

Topical N-Acetylcysteine Improves Wound Healing Comparable to Dexpanthenol: An Experimental Study

In this study, we aimed to compare the effects of dexpanthenol and N-acetylcysteine on wound healing. The wound healing process is a multifaceted sequence of activities associated with tissue restoration process. A number of investigations and clinical studies have been performed to determine new approaches for the improvement of wound healing. A total of 30 rats were divided into 3 equal groups. A linear 2-cm incision was made in the rats'' skin. No treatment was administered in the first (control) group. Dexpanthenol cream was administered to the rats in the second group and 3% N-acetylcysteine cream was administered to the rats in the third group. The wound areas of all of the rats were measured on certain days. On the 21st day, all wounds were excised and histologically evaluated. The epithelialization and granulation rates between the groups were revealed to be similar in microscopic evaluations. Although the fibrosis was remarkable in the control group as compared with the other groups, it was similar in N-acetylcysteine and dexpanthenol groups. Angiogenesis rate was remarkable in the N-acetylcysteine group compared with the others. In multiple-comparison analysis, Dexpanthenol and N-acetylcysteine groups had similar results in terms of wound healing rates (P < 0.05), which were both higher than in the control group (P > 0.05). The efficacy of N-acetylcysteine in wound healing is comparable to dexpanthenol, and both substances can be used to improve wound healing.Key words: N-acetylcysteine, Dexpanthenol, Wound healingWound healing is a multifaceted sequence of activities associated with the tissue restoration process.¹ This activity takes place in 4 main steps: inflammation, proliferation, matrix deposition, and remodeling.^2,3 Moreover, there are many factors that might have harmful effects on the wound healing process. In this regard, there have been numerous analyses and clinical studies aiming to find new methods for the improvement of wound healing processes.⁴Dexpanthenol is the biologically-active alcohol of pantothenic acid, which leads to an elevation in the amount of coenzyme A in the cell. Dexpanthenol is extensively used in topical form, since it can easily penetrate the skin even at large local concentrations. When used in formulations, dexpanthenol is most effective for the stimulation of epithelialization, granulation, and the mitigation of itching.⁵N-acetylcysteine (NAC) is a prodrug that supplies bioavailable cysteine for glutathione replenishment and prevents oxidative damage as well as inflammation. It also leads to glutathione (GSH) formation in the body. Besides fostering angiogenesis, it is used to scavenge free radicals. NAC has a number of functions in the stages of repair process, including cell proliferation, migration, and scratch wound healing. Moreover, NAC has also been reported to promote wound healing in diabetic rats.⁶In this study, we aimed to compare the effects of dexpanthenol, a molecule that is widely used to improve wound healing, and NAC, a molecule that reduces oxidative stress and inflammation, on wound healing.     

Exercise testing induces fatal thromboembolism from mechanical mitral valve

Thromboembolism is still one of the most important complications of prosthetic heart valves. Embolism to a major coronary branch is rare, but acute proximal occlusions can be fatal, even when the coronary arteries are otherwise normal and intervention is rapid. We report a fatal complication of an exercise test in a patient who had a St. Jude bileaflet mitral valve. After an exercise test, a 42-year-old woman with a mechanical prosthetic valve had a severe hemodynamic collapse with acute ST segment changes. Coronary angiography showed a totally occluded left main coronary artery with TIMI grade 0 to 1 flow. Rapid injection of contrast material and the passage of a floppy guidewire through the thrombus restored a TIMI grade 3 flow. Angiography showed no coronary atherosclerostic involvement. Despite successful coronary reperfusion, intra-aortic balloon counterpulsation, and intensive medication, the patient died. This case demonstrates that exercise testing should be applied with great caution in patients with prosthetic valves, and only after a careful evaluation of valve function. We recommend transesophageal echocardiography prior to exercise testing in these patients.     

Body position and obstructive sleep apnea syndrome

In adults, influence of body position on the occurrence of respiratory events during sleep is recognized, and increased numbers of respiratory events occur when the supine position is assumed.1-4 In 1985, Orr et al. showed that body position did not influence respiratory events during sleep in children.5 Recently, Fernandes do Prado et al. showed that children had a lower obstructive apnea hypopnea index (AHI) in supine position.6 Results of these two studies are different from others performed on adults. Moreover, upper airway abnormalities were not considered in these studies.The aim of the present study was to evaluate the effect of body position on obstructive respiratory events in children with different upper airway findings.     

Intrauterine upper extremity thrombosis successfully treated with recombinant tissue plasminogen activator, enoxaparin and collagenase

Intrauterine ischemia of the limbs is a rare condition involving thrombosis and ischemia of the extremities before birth. The clinical presentation depends on the extremity affected as well as the timing of thrombosis. Very few cases with extremity hypoperfusion and gangrene due to intrauterine thrombosis have been reported in the literature, and therefore there is no consensus on the optimal therapeutic strategy for such cases. Presented here is a case of a newborn with intrauterine brachial arterial thrombosis of the right upper extremity who was successfully treated by a combination of recombinant tissue plasminogen activator, enoxaparin and collagenase application followed by surgery.     

Quantitative evaluation of right ventricle function by transthoracic echocardiography in childhood congenital heart disease patients with pulmonary hypertension

Introduction and Objective: The present study aims to quantitatively evaluate the right ventricle (RV) function by means of transthoracic echocardiography in normal children and childhood congenital heart disease patients with pulmonary hypertension. Patients and Methods: This study was conducted in a cohort including 40 healthy children and 30 pediatric patients with pulmonary hypertension who were diagnosed under close surveillance at the study center between October 2009 and November 2010. Results: Statistically significant differences were found between the patient and control groups for the right ventricle myocardial performance index (RVMPI), the left ventricle myocardial performance index (LVMPI), the tricuspid valve systolic flow velocity (Ts), the ratio of systolic pulmonary artery pressure to the right ventricle outflow tract systolic flow velocity time integral (sPAP/RVOT VTI), and the ratio of systolic pulmonary artery pressure to right ventricle outflow tract systolic flow velocity time integral × heart rate (sPAP/[RVOT VTI×HR]). When the children were divided into three groups based on their pulmonary vascular resistance significant differences emerged that predicted an increasing severity of RV dysfunction. Significant differences were also observed for the RVMPI, the LVMPI, and the Ts as well as for echocardiographic pulmonary flow (Qp) and systemic flow (Qs). Discussion: The present study demonstrates that echocardiographic parameters can be used for the quantitative detection of RV dysfunction in childhood congenital heart disease patients with high pulmonary artery pressure (systolic, diastolic, and mean) or pulmonary vascular resistance.     

Speaker Abstracts

Narcolepsy is a rare disorder characterised by sleep disturbances, cataplexy, sleep paralysis and hypnagogic, hypnopompic hallucinations. Although several treatment modalities, such as tricyclic antidepressants or selective serotonin reuptake inhibitors, have been used to treat different symptoms, there is no definite treatment for narcolepsy. Modafinil or amphetamine-like stimulants, such as dexamphetamine or methylphenidate, are used to treat sleepiness. Our case was a 58-year-old woman who was diagnosed as narcolepsy cataplexy syndrome. Her Epworth Sleepiness Scale (ESS) score was 14 and Beck Depression Inventory (BDI) score was 29 in the first evaluation. Imipramine and modafinil were begun for the treatment, but there was no improvement in her symptoms. Subsequently, bupropion was started at 150 mg/day and then dosage was increased to 300 mg/day. She was asymptomatic at the end of 3 months. To our knowledge, this is the second depressive narcoleptic patient who has responded to 300 mg/day of bupropion.