Ulrich Franken

Impact of papillary muscles in ventricular volume and ejection fraction assessment by cardiovascular magnetic resonance.

Cardiovascular magnetic resonance (CMR) is an accurate tool for the determination of right and left ventricular volumes and ejection fractions. However, the current standard short-axis technique is time-consuming and thus, often not practicable for routine daily use, because papillary muscles and trabeculations have to be marked and their volumes subtracted from the total ventricular volume. To reduce calculation time we evaluated the volumetric data that included papillary muscle and trabecular volumes and compared the outcome with the results of the standard technique. Thirty patients (17 healthy, 13 with coronary heart disease) were examined by CMR using TrueFISP (Magnetom, Siemens, Erlangen, Germany). Right and left ventricular volumes and ejection fractions were calculated using the standard short-axis technique and then again without subtracting papillary and trabecular volumes. The two methods were compared by determining the differences in results for ventricular volumes and ejection fractions. Statistically significant differences were found between the two methods for right and left ventricular stroke volumes and end-systolic volumes, and left ventricular end-diastolic volumes (EDV) (p < or = 0.011). No significant difference was found for right ventricular end-diastolic volumes (p > or = 0.149) or left or right ventricular ejection fraction (p > or = 0.130). Except in the case of left ventricular EDV, the deviations in the results of method 1 and method 2 did not vary significantly with the presence or absence of heart disease. Measurements were obtained considerably more quickly with the modified method than with the standard short-axis method (25 +/- 4 min vs. 13 +/- 3 min, p = 0.000). Although systematic differences were found when papillary and trabecular volumes were not subtracted, these differences are small and may not be of clinical relevance in healthy subjects or patients with coronary heart disease. Not subtracting the volumes of these structures enables faster determination of right and left ventricular volumes and ejection fractions without loss of the accuracy associated with the standard short-axis technique.

Right Ventricular Wall Motion Abnormalities Found in Healthy Subjects by Cardiovascular Magnetic Resonance Imaging and Characterized with a New Segmental Model

AIM To evaluate right ventricular wall motion abnormalities in healthy subjects using a new segmental model for the right ventricle. METHODS AND RESULTS 29 healthy subjects (9 female, 20 male, mean age 48.9+/-15 years) underwent cardiovascular magnetic resonance imaging (CMR; 1.5-Tesla Sonata, Siemens, Erlangen, Germany) for the evaluation of cardiac function and right ventricular wall motion. A steady-state free precession gradient-echo sequence (TrueFISP) was used. Right ventricular wall motion was analyzed, and the site of areas of disordered motion was classified according to the new segmental model. Such areas were seen in 27 (93.1%) of the 29 subjects. Dyskinesia was found in 22 subjects (75.9%), hypokinesia in 11 (37.9%), and bulging in 8 (27.6%). The number of wall motion abnormalities diagnosed was significantly higher in the transverse plane (86.2%) than in the short-axis plane (13.8%) and the horizontal longitudinal plane (41.4%; p = 0.000). CONCLUSION Right ventricular wall motion abnormalities are one of the criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy. However, our findings indicate that they may also be seen around the insertion of the moderator band in healthy subjects, so that the significance of their presence at this site in patients undergoing diagnostic investigations for this disease should be interpreted with caution.

Single and biplane TrueFISP cardiovascular magnetic resonance for rapid evaluation of left ventricular volumes and ejection fraction.

INTRODUCTION Cardiovascular magnetic resonance (CMR) allows very accurate, but time-consuming, volume assessment by the short-axis slice summation technique. The single and biplane methods of volume assessment are used less, partly because FLASH cine imaging provides poor blood-myocardium contrast in long-axis views. TrueFISP gives excellent blood-myocardium contrast, even in patients with heart failure. We hypothesized that the single plane and biplane methods of volume assessment in TrueFISP images might provide an acceptable degree of accuracy and be quicker than the short axis method, and that single and biplane left ventricular volume assessment would be more accurate with TrueFISP than with FLASH in patients with impaired ventricular function. METHODS Short- and long-axis CMR images were obtained by FLASH and TrueFISP with a 1.5-T scanner. We determined the accuracy of both single and biplane long-axis methods for left ventricular volume and ejection fraction (EF) measurements compared with the conventional short-axis method in 10 heart failure patients using both FLASH and TrueFISP and in 9 healthy subjects using TrueFISP. RESULTS No difference in volumes and EF was found between the single plane method, the biplane method, and the short-axis method using TrueFISP for image acquisition, in both patients and healthy subjects. The same was true of the results obtained by FLASH in the patients with heart failure. CONCLUSIONS The single and biplane methods, regardless of whether TrueFISP or FLASH is used, are a reasonable and rapid alternative to the conventional short-axis approach for left ventricular volume and EF assessment in patients with heart failure and impaired ventricular function.

Impact of the ECG gating method on ventricular volumes and ejection fractions assessed by cardiovascular magnetic resonance imaging

PURPOSE Most MRI centers currently use prospective ECG triggering and fast gradient-echo sequences for image acquisition. Retrospectively gated sequences allow the coverage of the entire cardiac cycle. There is concern about whether ventricular volumes and ejection fraction (EF) differ according to the gating method used for image acquisition. We sought to evaluate the impact of the gating method on measurements of right and left ventricular volumes and EF in normal subjects. MATERIALS AND METHODS Fifteen subjects with no cardiovascular disease were investigated by MRI using a 1.5 Tesla scanner. Images were acquired with a gradient-echo sequence with steady-state free precession (SSFP) using the standard short-axis method for volume and EF measurements. Images were acquired with 6-mn-thick slices using both prospective triggering and retrospective gating. Left and right ventricular volumes (EDV, ESV, SV) and EF were determined with a commercially available software package (Argus, Siemens). RESULTS EDV and SV calculated from short-axis images were significantly smaller with the prospectively triggered SSFP sequence (mean difference: EDV left: 13.9 +/- 4.4 mL, p < 0.0001; SV left: 13.5 +/- 4.8 mL, p < 0.0001; EDV right: 14.2 +/- 3.9 mL, p < 0.0001; SV right: 14.7 +/- 5.9 mL, p < 0.0001). EF was significantly smaller for the right ventricle (mean difference -3.6 +/- 3.3%, p = 0.0008) and the left ventricle (mean difference -2.3 +/- 3.3%, p = 0.02). ESV remained unchanged (mean difference: ESV left: 0.47 +/- 3.5 mL, p = 0.6179; right ESV: 0.5 +/- 3.7 mL, p = 0.6083). CONCLUSION The gating method has a significant impact on volume and EF measurements. The global ventricular EF is underestimated by using the prospective triggering technique. However, the difference in the left ventricle is small and might not be of clinical relevance.

How Much are Atrial Volumes and Ejection Fractions Assessed by Cardiac Magnetic Resonance Imaging Influenced by the ECG Gating Method

PURPOSE Most magnetic resonance imaging (MRI) centers currently use prospective electrocardiographic (ECG) triggering for image acquisition. Retrospectively gated sequences allow the coverage of the entire cardiac cycle. It has been recently shown that ventricular volumes and ejection fraction (EF) differ according to the gating method used for image acquisition. The authors sought to evaluate how much measurements of atrial volumes and EF differ depending on the gating method. MATERIALS AND METHODS Eighteen subjects with no cardiovascular disease were investigated by MRI using a 1.5 Tesla scanner. Images were acquired with a gradient-echo sequence with steady-state free precession (SSFP) using the standard short-axis method for volume and EF measurements. Images were acquired with 6 mm thick slices using both prospective triggering and retrospective gating. Left and right atrial volumes (end diastolic volume [EDV]; end systolic volume [ESV]; stroke volume [SV]) and EF were determined with a commercially available software package. RESULTS ESV was significantly smaller with the retrospectively gated SSFP sequence than with the prospectively triggered sequence (mean difference: ESV left 3.97 +/- 1.3 ml, p < 0.0001; ESV right 4.34 +/- 1.8 ml, p < 0.0001). EF and SV were significantly smaller with prospective triggering (mean difference: EF left -5.94 +/- 0.9%, p < 0.0001; EF right -5.52 +/- 1.3 %, p < 0.0001; SV left -3.99 +/- 1.3 ml, p < 0.0001; SV right -4.32 +/- 1.9 ml, p < 0.0001). EDV remained unchanged (mean difference: EDV left -0.03 +/- 0.8 ml, p = 0.902; right EDV 0.04 +/- 0.7 ml, p = 0.882). CONCLUSION The gating method has a significant impact on atrial volume and EF measurements. Atrial EF is underestimated by using the prospective triggering technique.

Identifizierung rechtsventrikulärer Wandbewegungsstörungen bei gesunden Probanden mittels der kardiovaskulären Magnetresonanztomographie anhand eines neuen Segmentmodells: Bedeutung für die Diagnose der arrhythmogenen rechtsventrikulären Kardiomyopathie

Ziel: Evaluierung von rechtsventrikularen Wandbewegungsstorungen (RV-WBST) bei gesunden Probanden mittels der kardiovaskularen Magnetresonanztomographie (MRT) unter Verwendung eines neuen Segmentmodells. Material und Methoden: 29 gesunde Probanden (9 Frauen, 20 Manner, mittleres Alter 48.9±15 Jahre) wurden mittels der MRT (l,5-Tesla-Magnetom, Siemens, Erlangen) zur Evaluierung der rechtsventrikularen Funktion und auf das Vorliegen von RV-WBST untersucht. Zur Bildakquisition wurde eine Gradienten-Echo-Sequenz mit steady-state free precession (TrueFISP) verwandt. Die rechtsventrikulare Wandbewegung wurde anhand des Segmentmodells von 2 unabhangigen Untersuchern in der Transversal-, Kurzachsen- und horizontalen Langsachsenebene analysiert und klassifiziert. Ergebnisse: Bei 27 (93,1%) der 29 Probanden (Prob) wurden RV-WBST identifiziert. 22 Prob (75,9%) hatten eine Dyskinesie, 11 Prob (37,9%) hatten eine Hypokinesie und 8 Prob (27,6%) ein bulging. RV-WBST waren in der Transversalebene (86,2%) signifikant haufiger als in der Kurzachsenebene (13,8%) und der horizontalen Langsachsenebene (41,4%; p=0,00). 7 (24,1%) Prob zeigten keine Relation der WBST zur Insertion des Moderatorbandes und der Muskelbander. Die meisten WBST befanden sich rechtslateral (51,2) oder zwischen (48,3%) der Insertion der Muskelbander. Es zeigt sich eine gute Ubereinstimmung zwischen den beiden Untersuchern (Kappa ≥0.95) Der mittlere Diameter der WBST betrug 1.1±0.6cm. Schlussfolgerung: RV-WBST gehoren zu den Kriterien fur die Diagnose der arrhythmogenen rechtsventrikularen Kardiomyopathie (ARVC). Wir konnten zeigen, dass mittels der MRT bei gesunden Probanden RV-WBST im Bereich der Insertionsstelle der Muskelbander vorkommen. Derartige WBST sollten daher mit Vorsicht beurteilt werden, wenn es um die Diagnose der ARVC geht.