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Item does not contain fulltext OBJECTIVES: The reproducibilities of CT lung volume and densitometric measures of emphysema were assessed over 1 week. The influence of breathhold on reproducibility was assessed. METHODS: HRCT was performed on 44 subjects at inspiration on two visits with a 7-day interval. CT lung volume, relative area below -950HU (RA950-raw), and 15th percentile density (PD15-raw) were computed. Volume correction was used to obtain RA950-adj and PD15-adj. Reproducibilities between visits were assessed using concordance correlation coefficient (CCC) and repeatability coefficient (RC). Reproducibilities were compared between raw and adjusted measures. Differences between visits were computed for volume and density measures. Correlations were computed for density differences versus volume difference. Subgroup analysis was performed using a 0.25 L volume difference threshold. RESULTS: High CCC were observed for all measures in full group (CCC > 0.97). Reproducibilities of volume (RC = 0.67 L), RA950-raw (RC = 2.3%), and PD15-raw (RC = 10.6HU) were observed. Volume correction significantly improved PD15 (RC = 3.6HU) but not RA950 (RC = 1.7%). RA950-raw and PD15-raw had significantly better RC in /=0.25 L. Significant correlations with volume were observed for RA950-raw and PD15-raw (R (2) > 0.71), but not RA950-adj or PD15-adj (R (2) < 0.11). CONCLUSIONS: Good breathhold and RA950 reproducibilities were achieved. PD15 was less reproducible but improved with volume correction or superior breathhold reproduction. KEY POINTS : * Good breath-hold reproducibility is achievable between multiple CT examinations. * Reproducibility of densitometric measures may be improved by statistical volume correction. * Volume correction may result in decreased signal. * Densitometric reproducibility may also be improved by achieving good breath-hold reproduction. * Careful consideration of signal and noise is necessary in reproducibility assessment. 01 februari 2012

This study investigated the reproducibility of HRCT densitometric measures of emphysema in patients scanned twice one week apart. 24 emphysema patients from a multicenter study were scanned at full inspiration (TLC) and expiration (RV), then again a week later for four scans total. Scans for each patient used the same scanner and protocol, except for tube current in three patients. Lung segmentation with gross airway removal was performed on the scans. Volume, weight, mean lung density (MLD), relative area under -950HU (RA-950), and 15 th percentile (PD-15) were calculated for TLC, and volume and an airtrapping mask (RA-air) between -950 and -850HU for RV. For each measure, absolute differences were computed for each scan pair, and linear regression was performed against volume difference in a subgroup with volume difference

A new emphysema treatment uses endobronchial valves to perform lobar volume reduction. The degree of fissure completeness may predict treatment efficacy. This study investigated the behavior of a semiautomated algorithm for quantifying lung fissure integrity in CT with respect to reconstruction kernel and dose. Raw CT data was obtained for six asymptomatic patients from a high-risk population for lung cancer. The patients were scanned on either a Siemens Sensation 16 or 64, using a low-dose protocol of 120 kVp, 25 mAs. Images were reconstructed using kernels ranging from smooth to sharp (B10f, B30f, B50f, B70f). Research software was used to simulate an even lower-dose acquisition of 15 mAs, and images were generated at the same kernels resulting in 8 series per patient. The left major fissure was manually contoured axially at regular intervals, yielding 37 contours across all patients. These contours were read into an image analysis and pattern classification system which computed a Fissure Integrity Score (FIS) for each kernel and dose. FIS values were analyzed using a mixed-effects model with kernel and dose as fixed effects and patient as random effect to test for difference due to kernel and dose. Analysis revealed no difference in FIS between the smooth kernels (B10f, B30f) nor between sharp kernels (B50f, B70f), but there was a significant difference between the sharp and smooth groups (p = 0.020). There was no significant difference in FIS between the two low-dose reconstructions (p = 0.882). Using a cutoff of 90%, the number of incomplete fissures increased from 5 to 10 when the imaging protocol changed from B50f to B30f. Reconstruction kernel has a significant effect on quantification of fissure integrity in CT. This has potential implications when selecting patients for endobronchial valve therapy.

This study aims to evaluate the separability of bone from iodine- and gadolinium-based intravenous contrastagents using dual energy CT techniques in a phantom. The phantom was prepared containing varying concen-trations of iodine-based contrast, gadolinium-based contrast, and calcium hydroxyapatite (to simulate bone).Thirteen iodine concentrations from 0.1 to 12 mg/mL, twelve gadolinium concentrations from 0.72 to 34.42mg/mL, and four calcium concentrations from 0 to 200 mg/mL were used. These phantoms were scanned ona dual source CT using two die rent source spectra, producing one set of data at 80 kVp and another at 140kVp. On each resulting image, the mean HU was measured at every concentration level for iodine, gadolin-ium, and calcium, and plotted on a graph of HU value at 80 versus 140 kVp. Linear regression was used toproduce a best-“t line for each material. These lines were compared to test for a die rence of slopes betweencalcium and iodine as well as between calcium and gadolinium. Each material exhibited a linear relationshipbetween the HU values at 140 and 80 kVp ( R

Plasma process induced damage on rapid thermal nitrided oxide (RTNO) and decoupled plasma nitrided oxide (DPNO) gate dielectrics are evaluated. It is found that the level of plasma induced damage on DPNO is comparable to that of RTNO. Hence, we can conclude that the decoupled plasma nitridation (DPN) process does not introduce significant damage to the silicon dioxide gate dielectric. We also discovered that RTNO fares better than DPNO in term of plasma charging damage immunity when both gate dielectrics are subjected to simulated plasma charging stresses.

Plasma induced charging damage from polysilicon gate etch was studied using both end-of-line polysilicon antenna test structures and in-line surface potential measurement (SPM) techniques. This study is performed on a 0.15 /spl mu/m gate patterning process using two different polysilicon etch chambers. In the study, the standard deviation and range of surface potentials obtained from the SPM technique show the same trend as those of threshold voltages obtained from polysilicon antenna test structures. The SPM technique could be used as an add-on method to antenna test structures for monitoring plasma induced charging damage.

The effects of the poly-Si annealing on gate oxide charging damage in the gate etching process were investigated. Our electrical test results show that gate oxide charging damage can be reduced if the poly-Si is not annealed prior to the gate etching process.

Introduction:This study aims to characterize patients with Brugada syndrome (BrS) in Singapore, and its association with SCN5A-encoded cardiac sodium channel mutations.Methods:The study population consisted of 30 unrelated individuals (28 males, 93%) with either spontaneous or drug induced type 1 coved ST-segment elevation in leads V1–V3.Results:The mean age of symptom onset was 40.8 years (SD 13.5, min 11, max 72). The mean follow up duration was 3.6 years. Nine patients had an ICD implanted, none had appropriate ICD shocks.Mutation in the SCN5A gene was found in 5 out of the 30 individuals (16.7%). The PR interval in SCN5A mutation carriers was significantly prolonged (201.40 +/− 28.35 ms vs 168.92 +/− 27.67 ms, p=0.024). One individual had compound heterozygous mutation and presented with syncope and VT at the age of 11. A total of 6 mutations were identified, four of which were novel (67%).Conclusion:In this study, a mutation in the SCN5A gene was found in 16.7% of patients with BrS. The presence of a SCN5A mutation results in a longer PR interval. Compound heterozygosity in one individual appears to confer a more severe phenotype and an earlier onset of symptoms.

Permanent cardiac pacing is the treatment of choice in patients with symptomatic bradyarrhythmias. The SCDB is a prospective registry of interventional cardiac procedures done in Singapore since July 2000. This report looks at the data from NHC during the period from 2000–2010. There were 1724 pacemakers implanted during the 10 year with almost yearly increase in the number of pacemakers implanted at this single centre. The mean age of the patients was 69.86 years+12.2 old (median 71 years old, range 11–98 years). Over the 10 year period, there were more females (54.2% females vs 45.8% males). Sick sinus syndrome remains the most common indication for pacemaker implantation (60.7%) and the second most common indication was AV block (35.3%). This trend was consistently seen over the decade. The number of females was higher in the sick sinus syndrome group (59.8% females vs 40.2% males) whereas the proportion of males was higher in the complete heart block group (46.5% females vs 53.5% males). In conclusion, there is an increase in the number of pacemakers implanted likely due to an aging population. Females remain consistently higher and sick sinus syndrome remains the most important indication for pacing. With the rapidly aging population, it would be expected that this trend would continue to increase over the next decade.

Catheter ablation provides curative treatment of outflow tract VT or frequent symptomatic ventricular arrhythmias. The remote magnetic navigation system (Stereotaxis) involves moving a catheter with a magnetic tip inside a 0.08–0.1 Tesla magnetic field and mapping done with the CARTO and ablation with a coolflow catheter. We report our experience with the Stereotaxis from July 2009 to May 2011 for ablation of outflow tract VA. There were 42 pts (19 males: 23 females) with a mean age of 45.0+13.8 years. The arrhythmias were RVOT VT in 37, aortic cusp VT 4 and aorto-mitral in 1. 72% of the patients had the procedure done with a single catheter only. The mean procedure time was 160.7+69.6 mins (range 63–330 mins) and mean fluoroscopy time 15.4+22.0 mins (range 1.0–120 mins). When compared to a previous group of 44 outflow tract VT ablation using manual technique, the mean procedure time was 153.9+55.4 mins (80–285 mins) and mean fluoroscopy time was 39.3+25.8 mins (10.9–117.6 mins). Acutely 92.8% of the cases were successfully ablated. There were no major complications. In conclusion, remote magnetic navigation with the Stereotaxis allows precise mapping and successful ablation in the majority of pts with outflow tract ventricular arrhythmias. The procedure time is not reduced significantly but there is a reduction in fluoroscopy time.

Background: Catheter ablation of atrial fibrillation (AF) remains a challenging procedure. We aim to describe the EP characteristics of patients who underwent 2 or more ablations for AF. Methods: 17.7% of 243 patients (n=43) underwent repeat ablation for drug refractory AF. All patients underwent instrumentation of the left atrium (LA) after LA clots were excluded. Mapping of the pulmonary veins (PVs) and ablation to achieve PV isolation was performed. Additional triggers after induction were ablated. Results: The types of AF were paroxysmal AF (PAF) (n=25) or non-paroxysmal AF (NPAF) (n=18). Recovered PV potentials were seen in 97.7%: LSPV: 93%, RSPV 86%, RIPV 84% and LIPV 76%. 76.7% (n=33) of patients required additional ablation. NPAF patients required more ablation than PAF: CFAE (77.8% vs 8%, p

Introduction: We report two cases of recurrent VT, successfully controlled by EndoEpicardial ablation using Stereotaxis System. Case 1: 65 year female had ICD, PTCA and Mitral valve replacement, presented with recurrent monomorphic VT (CL 430 ms, LBBB superior axis), LVEF 20%. Mapping done with CARTO and Stereotaxis. RF ablation at earliest endocardial activation and low voltage areas unable to terminate VT. Epicardial approach was attempted via pericardial window. Earliest activation and presystolic potentials noted in mid posterior septal LV, RF ablation at this site terminated the VT. Subsequently slower VT 2 (CL 520 ms) was induced with earliest activation more laterally. RF ablations in mid posterior LV from lateral LV to near the septum terminated VT. Case 2: 43 year male case of dialated cardiomyopathy, LV dysfunction (EF 25%) previously failed endocardial RF ablation for VT. Percutaneous subxiphiod epicardial access was obtained. VT1 (CL 610 ms, right inferior axis, RBBB pattern) was spontaneously induced during epicardial instrumentation. Scar and area of double potentials mapped epicardially at basal anterolateral LV. Ablation at this site terminated VT. PES subsequently induced VT2 (CL 340 ms) and VT3 (CL 210 ms). Both VT mapped and ablated endocardially. Conclusion: Enhanced maneuverability of catheter by using Stereotaxis permits accurate mapping of difficult reach areas, with minimal trauma to cardiac tissue and radiation exposure.

Background: In secondary prevention patients, ICD detection zones are often tailored individually. We aim to determine whether patients initial presenting VT tachycardia cycle length (TCL) prior to ICD implant predicts subsequent VT TCL.Methods: All secondary prevention ICD patients on follow up with available records of appropriate ICD therapy for VT within a 3-year period were studied.Results: 249 VT events in 20 patients were analysed. Mean age 55.8 years, median 5-years follow up. All had sustained VT on 12-lead ECG prior to ICD implant. Mean presenting VT TCL was 313±46 (SD) ms. In majority, post implant VT TCL increased by 20–50 ms compared to at presentation (R=0.52, p=0.02). In the entire group, mean TCL of VTs post implant was 350±43 (SD) ms. Reasons for the increased TCL include medications, ischaemia, scar size changes and different VT circuits.Conclusion: In our population, VT cycle lengths post implant are on average longer, but remain correlated to presenting TCL. Detection cycle lengths 50 ms longer than the TCL of the presenting VT should be programmed if under-detection of subsequent VTs is to be minimised.

Introduction: Medtronic Ventricular Capture Management (VCM) allows effective long-term management of the pacing output and thus, maximises battery longevity. The aim of this study is to determine the accuracy of the VCM and results were comparable with in-office manual threshold results (MTR). Method: Patients with bradyarrhythmia indications who received a Medtronic device with VCM were recruited. Clinical demographics were collected and analysed. The VCM data was analysed and compared with in-office MTR. VCM was turned on only 3 months after implantation. Results: There were 30 patients (13 male, 17 female) of mean age 71 years old. 13% received single chamber pacemaker. The mean duration of initial implantation was 2.5 years. 14 patients (46.7%) had identical VCM threshold results and in-office MTR. 15 patients (50%) had+0.25 V difference between VCM threshold results and in-office MTR. Only 1 patient (3.3%) was shown to have 0.5 V difference between VCM threshold results (1.125 V @ 0.4 ms) and in-office MTR (0.625 V @ 0.4 ms). Conclusion: VCM is considered to be accurate and comparable to in-office manual threshold tests at least 3 months after device implantation. VCM reliability will allow proper management of the pacing output by adjusting accordingly to the threshold obtained automatically.

42-year-old female presented with pressure like mid chest pain radiating to the left arm with some difficulty in breathing but described no aggravating or relieving factor. She had no prior personal or family history of cardiovascular disease. She was hemodynamically stable and had normal physical examination relevant to cardiac and pulmonary systems. EKG showed biphasic T-waves in lead V2, V3 on presentation which later progressed to deep and symmetrical T wave inversions in precordial leads. Troponins were mildly elevated. Stress testing was positive. She had a cardiac catheterization revealing 99% stenosis in proximal LAD accompanied with 70% ostial stenosis in D1. Successful PTCA with stent placement in LAD and D1 branch was conducted. Her medication regimen was optimized and she was discharged home in stable condition. Critical high grade occlusion of the proximal LAD (Wellens Syndrome) was first described in 1982 by Dr. Hein J. Wellens. Diagnostic criteria include a recent history of chest pain, normal to slightly elevated serum markers, lack of pathological Q waves or ST-segment elevation. T waves are symmetrically and deeply inverted in the precordial leads or are biphasic in V2 and V3 leads (Wellen’s sign). Appropriate assessment with rapid intervention is paramount in managing these patients as unidentified cases can progress to extensive anterior wall MI and have a worse outcome. It is absolute essential not to rely on computer generated readings in such cases as this can lead to unwarranted noninvasive testing which may have untoward consequences.

This paper makes a normative argument for the greater strategic utilization of human rights institutions, practices, and discourses by those seeking a robust response to climate change. Bandwagoning between these two regimes is hardly a new thing. The environmental movement has long looked to the human rights movement for ideas and support, and vice versa. Here, we argue that there is potential for even more explicit bandwagoning in ways that will most directly benefit those who are suffering, and will continue to suffer, from climate change's greatest impacts. The human rights framework offers a guide to more effective climate action via two interconnected arenas: a legal arena that provides an established set of tools for climate activists, and a political arena that provides a normative underpinning for a range of judicial and non-judicial actions in support of ‘climate justice.’ Ultimately, moral and strategic guidance from the human rights movement points the way to a more equitable and enduring climate politics, with fairness at its heart.