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Quantitative cardiac function assessment remains a challenge for physiologists and clinicians. Although historically invasive methods have comprised the only means available, the development of noninvasive imaging modalities (echocardiography, MRI, CT) having high temporal and spatial resolution provide a new window for quantitative diastolic function(More)
Pressure-volume (P-V) loop-based analysis facilitates thermodynamic assessment of left ventricular function in terms of work and energy. Typically these quantities are calculated for a cardiac cycle using the entire P-V loop, although thermodynamic analysis may be applied to a selected phase of the cardiac cycle, specifically, diastole. Diastolic function(More)
The slope of the diastatic pressure–volume relationship (D-PVR) defines passive left ventricular (LV) stiffness $$ \mathcal{K}.$$ Although $$ \mathcal{K} $$ is a relative measure, cardiac catheterization, which is an absolute measurement method, is used to obtain the former. Echocardiography, including transmitral flow velocity (Doppler E-wave) analysis, is(More)
Although the electrophysiologic derangement responsible for atrial fibrillation (AF) has been elucidated, how AF remodels the ventricular chamber and affects diastolic function (DF) has not been fully characterized. The previously validated Parametrized Diastolic Filling (PDF) formalism models suction-initiated filling kinematically and generates(More)
BACKGROUND Pseudonormal Doppler E-wave filling patterns indicate diastolic dysfunction but are indistinguishable from the normal filling pattern. For accurate classification, maneuvers to alter load or to additionally measure peak E' are required. E-wave deceleration time (DT) has been fractionated into its stiffness (DTs) and relaxation (DTr) components(More)
Echocardiographic diastolic function (DF) assessment remains a challenge in atrial fibrillation (AF), because indexes such as E/A cannot be used and because chronic, rate controlled AF causes chamber remodeling. To determine if echocardiography can accurately characterize diastolic chamber properties we compared 15 chronic AF subjects to 15, age matched(More)
Abstract Although catheterization is the gold standard, Doppler echocardiography is the preferred diastolic function (DF) characterization method. The physiology of diastole requires continuity of left ventricular pressure (LVP)-generating forces before and after mitral valve opening (MVO). Correlations between isovolumic relaxation (IVR) indexes such as(More)
PURPOSE Calculation-based patient-specific IMRT/VMAT QA, as a DICOM-RT-based plan verification system, has been commissioned and is currently being used at our institution. We report our investigation of IMRT/VMAT plan verification failures/warnings out of more than 1,000 plans verified over an 18-month period. METHODS Seven patients with QA(More)
PURPOSE Appropriate MLC QA is important to assure treatment accuracy. In addition to the TG-142 recommended picket fence test, our institution performs four MLC tests on a weekly basis. The purpose of this study was to evaluate the clinical necessity of our weekly MLC QA program after a two-year run. METHODS Our Weekly MLC QA tests: 1) MLC positioning; 2)(More)
PURPOSE GammaPod™, the first stereotactic radiotherapy device for early stage breast cancer treatment, has been recently installed and commissioned at our institution. A multidisciplinary working group applied the failure mode and effects analysis (FMEA) approach to perform a risk analysis. METHODS FMEA was applied to the GammaPod™ treatment process by:(More)