Three-Dimensional Echocardiographic Analysis of Left Ventricular Function during Hemodialysis

Background: The effects of hemodialysis (HD) on left ventricular (LV) function have been studied by various echocardiographic techniques (M-mode, 2D echocardiography). These studies are hampered by a low accuracy of measurements because of geometric assumptions regarding LV shape. Three-dimensional echocardiography (3DE) overcomes this limitation. Methods: We tested the feasibility of 3DE assessment of LV function during HD. Conventional biplane Simpson rule (BSR) and single plane area length method (SPM) for LV function analysis were used as a reference. Results: 12 HD patients were studied and in 10 (83%) a total of 80 3D datasets were acquired. In 3 patients, one dataset (4%) was of insufficient quality and excluded from analysis. Correlation between SPM, BSR and 3DE for calculation of end-diastolic (EDV, r = 0.89 and r = 0.92, respectively), end-systolic volume (ESV, r = 0.92 and r = 0.93, respectively) and for ejection fraction (EF, r = 0.90 and r = 0.88, respectively) was moderate. Limits-of-agreement results for EDV and ESV were poor with confidence intervals larger than 30 ml. Both 2DE methods underestimated end-diastolic and end-systolic volume, while overestimating ejection fraction. Conclusion: 3DE is feasible for image acquisition during HD, which opens the possibility for accurate and reproducible measurement of LV function during HD. This may improve the assessment of the acute effect of HD on LV performance, and guide therapeutic strategies aimed at preventing intradialytic hypotension

Variation in neurosurgical management of traumatic brain injury

Background: Neurosurgical management of traumatic brain injury (TBI) is challenging, with only low-quality evidence. We aimed to explore differences in neurosurgical strategies for TBI across Europe. Methods: A survey was sent to 68 centers participating in the Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. The questionnaire contained 21 questions, including the decision when to operate (or not) on traumatic acute subdural hematoma (ASDH) and intracerebral hematoma (ICH), and when to perform a decompressive craniectomy (DC) in raised intracranial pressure (ICP). Results: The survey was completed by 68 centers (100%). On average, 10 neurosurgeons work in each trauma center. In all centers, a neurosurgeon was available within 30 min. Forty percent of responders reported a thickness or volume threshold for evacuation of an ASDH. Most responders (78%) decide on a primary DC in evacuating an ASDH during the operation, when swelling is present. For ICH, 3% would perform an evacuation directly to prevent secondary deterioration and 66% only in case of clinical deterioration. Most respondents (91%) reported to consider a DC for refractory high ICP. The reported cut-off ICP for DC in refractory high ICP, however, differed: 60% uses 25 mmHg, 18% 30 mmHg, and 17% 20 mmHg. Treatment strategies varied substantially between regions, specifically for the threshold for ASDH surgery and DC for refractory raised ICP. Also within center variation was present: 31% reported variation within the hospital for inserting an ICP monitor and 43% for evacuating mass lesions. Conclusion: Despite a homogeneous organization, considerable practice variation exists of neurosurgical strategies for TBI in Europe. These results provide an incentive for comparative effectiveness research to determine elements of effective neurosurgical care

3D Harmonic Echocardiography:

Three dimensional (3D) echocardiography has recently developed from an experimental technique in the ’90 towards an imaging modality for the daily clinical practice. This dissertation describes the considerations, implementation, validation and clinical application of a unique concept for harmonic 3D echocardiography. Part I firstly illustrates the advantages of harmonic imaging with a new transducer design tool, allowing the simulation of steered nonlinear acoustic beams. Then this dissertation introduces the fast rotating ultrasound (FRU-) transducer, which serves as a cost effective alternative for full- volume echocardiography with optimal harmonic capabilities. Measurement of the left ventricular (LV) volume has major diagnostic and prognostic importance. In the part II this basic application of the FRU-transducer is explored. Both a commercially available and self-developed quantification application are evaluated for LV volume measurement. Both quant! ification applications use advanced semi-automatic detection algorithms for endocardial border delineation. In addition, the efficiency of LV volume quantification is optimized by determining the minimal number of long-axis images required for accurate LV volume measurement. More advanced applications are investigated in part III. First, 3D echocardiography during hemodialysis is compared with two dimensional echocardiography. The study gives a good example of the flexible application of 3D echocardiography. Subsequently, the advantages of 3D contrast harmonic imaging are explored. Whether 3D echocardiog

Contrast-enhanced three-dimensional dobutamine stress echocardiography: Between Scylla and Charybdis?

Aims: Real-time three-dimensional echocardiography (RT3DE) allows quick volumetric scanning of the left ventricle (LV). We evaluated the diagnostic accuracy of contrast-enhanced stress RT3DE for the detection of coronary artery disease (CAD) in comparison with coronary arteriography as the reference technique. Methods and results: Forty-five consecutive patients (age 59 ± 10, 31 males) referred for coronary angiography were examined by contrast-enhanced RT3DE. Wall motion analysis was performed off-line by dedicated software. New or worsening wall motion abnormalities were detected in 17 of 28 patients with significant CAD (sensitivity 61%), and in two of 17 patients without significant CAD (specificity 88%). The sensitivity for detection of single-vessel CAD was 8/15 patients (53%), for two-vessel CAD 4/6 (67%), and for three-vessel CAD 5/7 (71%). In 35 patients, comparison with conventional RT3DE was available. The image quality index at rest improved from 2.5 ± 1.2 to 3.2 ± 1.0 (P < 0.001) with contrast and at peak stress from 2.3 ± 1.2 to 3.1 ± 1.0 (P < 0.001). Interobserver agreement on the diagnosis of myocardial ischaemia improved from 26 of 35 studies (74%, κ = 0.44) with conventional stress RT3DE to 30 of 35 studies (86%, κ = 0.69) with contrast-enhanced stress RT3DE. Sensitivity increased from 50 to 55% and specificity from 69 to 85% with contrast-enhanced stress RT3DE in this subset of patients. Conclusion: Despite some important practical and theoretical benefits, contrast-enhanced stress RT3DE currently has only moderate diagnostic sensitivity due to several technical limitations as temporal and spatial resolution

Guiding and optimization of resynchronization therapy with dynamic three-dimensional echocardiography and segmental volume-time curves: A feasibility study

Objective: To assess a new approach for guiding and hemodynamic optimization of resynchronization therapy, using three-dimensional (3D) transthoracic echocardiography. Background: Resynchronization therapy for heart failure provides the greatest hemodynamic benefit when applied to the most delayed left ventricular (LV) site. Currently, the ideal LV pacing site is selected according to acute invasive hemodynamic assessment and/or tissue Doppler imaging. Methods: A total of 16 patients with advanced heart failure and an implanted biventricular pacemaker were included in this study. Transthoracic apical LV images at equidistant intervals were obtained using a prototype, fast-rotating second harmonic transducer to reconstruct 3D LV datasets during sinus rhythm (SR), right ventricular (RV) apical and biventricular pacing mode. A semi-automated contour analysis system (4D LV analysis, TomTec, Germany) was used for segmental wall motion analysis and identification of the most delayed contracting segment and calculation of global LV function. Results: Data acquisition duration was 10 s and analyzable 3D images were obtained in 12 patients. Of these patients, data during SR were available i