Purpose: The current cardiac magnetic resonance (CMR) based approach to assessment of right ventricular (RV) volumes is time-consuming and not optimized for routine clinical use. This study tested a new CMR based 3-Dimensional (3D) method of RV volume estimation that employed automated tracking to reduce analysis time. Methods: Twenty RV-shaped latex models of different sizes (25-225 ml) were studied. Each RV model was driven by a pulsatile pump at 3-5 different stroke volumes (SV, 20-80 ml), and scanned for gradient cine stacks of multiple adjacent short axes, along with sagittal and coronal planes on a 3T MR scanner (Siemens). Individual scans were combined in an offline RV analysis program (RVMR) embedded in Research Arena VA® (TomTec) to compose a dynamic 3D polyhedron RV image loop. Each cine loop was analyzed using automated border tracking to compute RV volume. Reference volumes were obtained by immersing these models in water filled graduated cylinders and measuring displaced volume. Results: The 3D RVMR derived volumes showed strong correlation with displacement derived reference volumes (Spearman coefficient = 0.992 for ESV, 0.999 for EDV; all p < 0.0001). Good interand intra-observer variability was observed. The intra-class correlation coefficients for ESV were 0.993 and 0.998 respectively, and for EDV 0.989 and 0.995 respectively. Bland-Altman analysis showed >95% of data points within limits of agreement. Conclusions: Technical feasibility and accuracy of the 3D RVMR program was validated in this study. The speed of analysis is a distinct advantage. Studying normal and diseased human RVs would be the next step. List of Abbreviations: RV: right ventricle, CMR: cardiac magnetic resonance, CHD: congenital heart disease, 2D: two-dimensional, 3D: three-dimensional, EF: ejection fraction, ESV: end-systolic volume, EDV: end-diastolic volume, SV: stroke volume, TOF: tetralogy of fallot, RVOT: right ventricular outflow tract, SSFP: steady state free precession, True FISP: true fast imaging with steady state precession, DICOM: digital imaging and communications in medicine

AIMS:To evaluate right ventricular (RV) volume and ejection fraction (EF) in adult normal subjects and repaired tetralogy of Fallot (ToF) with 3D trans-thoracic echocardiography (3DE) and a semi-automatic border detection algorithm.METHODS AND RESULTS:Fourteen healthy volunteers and 20 patients with repaired ToF (mean age 31 +/- 14) underwent 3DE and MRI within the same day. Right ventricular end-systolic volume (ESV) and end-diastolic volume (EDV) and EF were measured by two observers using 3DE and compared with MRI measurements. Intra- and interobserver variability of 3DE and agreement between both methods were evaluated using Bland-Altman analysis. Over or underestimation of 3DE in comparison to MRI was assessed using paired t-test. Intra- and interobserver variability of 3DE was excellent with intraclass coefficient of correlation (ICC) ranging from 0.85 to 0.99 and from 0.85 to 0.98, respectively. Three-dimensional echocardiography underestimated ESV and EDV (P < 0.001) but agreement between 3DE and MRI was excellent (ICC = 0.88 and 0.87, respectively). Ejection fraction was 47.7 +/- 7.8 with 3DE and 47.9 +/- 6.7 with MRI, agreement between both methods was good (ICC = 0.72).CONCLUSION:Three-dimensional echocardiography combined to semi-automated quantification software shows fair agreement with MRI for RV volumes and EF measurement in patients with repaired ToF and adequate intra- and interobserver variability. These results suggest applicability for serial follow-up of patients with right heart congenital disease. However, the accuracy of 3DE echo diminishes with larger RV volumes, in part due to current difficulty to include the entire RV in the imaged sector. Technical progress in transducers beam geometry is likely to address this issue.

Our goal was to analyze myocardial tissue strain and twist in patients with post op tetralogy of Fallot (TOF) using a novel MR speckle tracking method for MR gradient-echo loops as relates to right...

OBJECTIVES:We tested a newly developed 4-dimensional (4D) right ventricular (RV) analysis method for computing RV volumes for both 3-dimensional (3D) ultrasound (US) and magnetic resonance (MR) images. BACKGROUND:Asymmetry and the anatomical complexity of the RV make accurate determination of RV shape and volume difficult. METHODS:Thirty patients, 14 with grossly normal cardiac anatomy and 16 with major congenital heart disease, were studied at the same visit with both 3D echocardiography (echo) and magnetic resonance imaging (MRI) for RV size and function. Ultrasound images were acquired on a Philips 7500 system (Philips Medical Systems, Andover, Massachusetts) with a matrix-array transducer (real-time 3D echo) with full volume sweeps from apical and subcostal views. Sagittal, 4-chamber, and coronal views were derived for contour detection (all 12 to 24 slices). The MR images were acquired with a 3-T MRI magnet with segmented cine-loop gradient echo sequences in short- and rotated long-axis views to cover the RV inflow, body, and outflow tract. The RV volumes were analyzed with the new software applicable to 3D echo MR images. RESULTS:New software aided delineation of the RV free wall, tricuspid valve, RV outflow tract, and apex on 3D echo volumes. Although there was a slightly higher variability measuring right ventricular ejection fraction (RVEF) and volumes obtained by US compared with MRI, both imaging methods showed closely correlated results. The RVEF was measured with 4% variability for US and 5% variability for MRI with a correlation coefficient of r = 0.91. The RV end-diastolic volume was measured at 70.97 +/- 15.0 ml with 3D US and at 70.06 +/- 14.8 ml with MRI (r = 0.99), end-systolic volume measured 39.8 +/- 10.4 ml with 3D US and 39.1 +/- 10.2 ml with MRI (r = 0.98). CONCLUSIONS:The new RV analysis software allowed validation of the accuracy of 4D echo RV volume data compared with MRI.

Background: Asymmetry and anatomical complexity of the right ventricle (RV) make accurate determination of RV shape and volume difficult. We tested a newly developed 4D semiautomated RV analysis so...

PURPOSE:To determine the mechanism of enhancement of contrast-enhanced MRI (ceMRI) in chronic ischemic myocardium. While ceMRI can identify scar tissue in chronic ischemic myocardium, the mechanism of enhancement is not completely understood. MATERIALS AND METHODS:A total of 11 patients with ischemic heart failure (ejection fraction [EF] 28 +/- 9%) were imaged with ceMRI and positron emission tomography (PET) to measure myocardial blood flow (MBF). Longitudinal relaxation rate (T1) of blood, normal tissue, and scar tissue defined by ceMRI was determined before and two to 50 minutes after contrast (Look Locker technique), and the partition coefficient (lambda) and volume of distribution (VD) were calculated. RESULTS:In scar and viable tissue, T1 was significantly different over the whole period after contrast, but not before contrast. However, T1 of scar and blood were similar five to 15 minutes post contrast, making the detection of subendocardial defects difficult. lambda reached an initial steady state in viable tissue, but was delayed (20 minutes) in scar tissue. VD in scar was double that of viable tissue (0.54 +/- 0.01 vs. 0.29 +/- 0.02, respectively) indicating an increased interstitial space. Contrast wash-in kinetics correlated moderately with MBF (r = -0.36), but well with the combination of MBF and VD (r = 0.59). CONCLUSION:Late myocardial contrast kinetics depend on both MBF and VD; however the increased VD seems to be the main mechanism for the late enhancement effect.

Die Stärke der modernen nuklearmedizinischen Diagnostik mit Hilfe der Positronen-Emissions-Tomographie (PET) ist der Einsatz physiologischer „Kontrastmittel“ in sehr geringen Konzentrationen. Allerdings sieht man sich zunehmend mit der Problematik konfrontiert, die Balance zwischen Akquisitionstechnologien, physiologisch-methodischem Wissen und Umsetzung in der Routine zu bewahren. Insbesondere die Möglichkeit, Studien zeitaufgelöst (dynamisch) oder in Abhängigkeit der Herzphasen (getriggert) zu messen, erweitert das Spektrum der funktionellen, nichtinvasiven Herzbildgebung - allerdings geht dies mit einem drastischen Anstieg der auszuwertenden Datenmengen einher. Um die Extraktion der physiologischen Informationen zu vereinfachen, wurde daher das Werkzeug “MunichHeart” entwickelt, das insbesondere die Gesichtspunkte Reproduzierbarkeit, Stabilität und Flexibilität im Forschungs- und Routineumfeld beinhaltet.

Zum Zweck einer orts-und plattformunabhängigen Möglichkeit der Visualisierung von DICOM 3.0-Daten wurde ein Java-Applet erstellt, das in jede Intra-und Internetanwendung eingebunden werden kann. Dieses Java-Applet interpretiert Bilddaten nach dem DICOM 3.0-Standard wie zum Beispiel CT-und MRT-Daten.