Daniela Föll

Detailed analysis of myocardial motion in volunteers and patients using high-temporal-resolution MR tissue phase mapping

To detect and investigate details in left ventricular (LV) motion patterns with a temporal resolution comparable to that of echocardiography.

Time-resolved three-dimensional magnetic resonance velocity mapping of cardiovascular flow paths in volunteers and patients with Fontan circulation

OBJECTIVE To apply flow-sensitive magnetic resonance imaging for the evaluation of whole-heart flow characteristics in healthy volunteers and patients with Fontan circulation. METHODS Time-resolved three-dimensional magnetic resonance velocity mapping (spatial resolution = 2.5 × 2.8 × 2.8mm(3), temporal resolution = 38.4 ms) was acquired in normal controls and in four Fontan patients with extracardiac total cavopulmonary connection. Data analysis included flow connectivity mapping and flow quantification of arterial and venous blood flow. Haemodynamics in four patients with Fontan circulation were individually evaluated in the aorta, caval veins and left and right pulmonary arteries. RESULTS In four controls, nine distinct flow features were consistently identified with good feature clarity (median = 2 in 80.6% of readings) and image quality (median = 2 in 75.0% of readings). In patients, a marked variability of flow from the caval veins towards the left and right pulmonary arteries (flow ratio = 1.7 ± 0.6, range 1.2-2.6 vs 1.1 ± 0.1 in controls) was found. Increased offset of the caval venous connection resulted in enhanced pulmonary flow asymmetry. Compared with controls, reduced pulsatility in pulmonary arteries (1.4 ± 0.6 vs 4.1 ± 0.6 in controls) and caval veins (1.2 ± 0.4 vs 2.8 ± 1.1 in controls) were observed. Peak flow was reduced in both superior (22 ± 14 mls(-1) vs 76 ± 7 mls(-1) in controls) and inferior vena cava (61 ± 28 mls(-1) vs 187 ± 42 mls(-1) in controls). CONCLUSIONS This feasibility study demonstrated the potential of whole-heart three-dimensional magnetic resonance velocity mapping to reveal overt haemodynamic differences in surgically palliated congenital heart with similar extracardiac cavopulmonary connection geometry. Future studies are warranted to evaluate its diagnostic impact for improved evaluation of the pre- and postoperative status in the individual patient.

Magnetic resonance tissue phase mapping of myocardial motion: new insight in age and gender.

Background—An exact understanding of normal age- and gender-matched regional myocardial performance is an essential perquisite for the diagnosis of heart disease. Magnetic resonance phase-contrast imaging (tissue phase mapping) enabling the analysis of segmental, 3-directional myocardial velocities with high temporal resolution (13.8 ms) was used to assess left ventricular motion. Methods and Results—Radial, long-axis, and rotational myocardial velocities were acquired in 58 healthy volunteers (3 age groups, 29 women) in left ventricular basal, midventricular, and apical short-axis locations. For increased age, reduced (P<0.003) and prolonged long-axis and radial velocities (P<0.05) during diastole and reduced long-axis velocities (P<0.001) and apical rotation (P<0.005) during systole were found for both genders. Women demonstrated a reduced systolic twist (P=0.009), apical rotation (P=0.01), and systolic radial velocities (P<0.02) compared with men. Segmental analysis of long-axis motion with aging revealed differences in regional reduction of systolic (lateral 52% versus 30%) and diastolic (lateral 57% versus 41%) velocities in women compared with men. In basal segments, young women demonstrated higher long-axis velocities (+11% during diastole) than men, whereas this difference was reversed in older subjects (same segments, −20%). In addition, increased age resulted in a prolonged time to peak diastolic apical rotation (P<0.04) in women compared with men. Conclusions—Age and gender strongly influence regional myocardial motion. Tissue phase mapping provides a comprehensive quantitative analysis of all myocardial velocities with high temporal and spatial resolution. The knowledge of the detected age- and gender-related differences in myocardial motion is fundamental for further investigations of cardiac disease. Clinical Trial Registration—http://www.zks.uni-freiburg.de/uklreg/php/suchergebnis_all.php. Identifier: UKF001739

Age, gender, blood pressure, and ventricular geometry influence normal 3D blood flow characteristics in the left heart

AIMS The aim of this study was to assess the effect of age, gender, physiological, and global cardiac function parameters on differences in normal 3D blood flow in the left ventricle (LV) and atrium (LA) using 4D flow magnetic resonance imaging (MRI). METHODS AND RESULTS Four-dimensional flow MRI was acquired in healthy volunteers of two age and gender groups: <30 years (6 women, n = 12) and >50 years (6 women, n = 12). Systolic and early to mid-diastolic vortex flow (number of vortices, duration, area, peak velocity inside the vortex) in the LA and LV was assessed using intra-cardiac flow visualization based on 3D particle traces and velocity vector fields. A larger number of vortices in the LA were found in young compared with older individuals (number of diastolic vortices: 1.6 ± 0.8 vs. 0.7 ± 0.7, P = 0.01) with higher velocities (54 ± 12 cm/s vs. 41 ± 11 cm/s in systole, 47 ± 13 vs. 31 ± 8 cm/s in diastole, P < 0.05). Vortices in the LV base were smaller in women compared with men (369 ± 133 vs. 543 ± 176 mm(2), P = 0.009), while vortex size was increased in mid-ventricular locations (maximum area: 546 ± 321 vs. 293 ± 174 mm(2), P < 0.05). Correlation analysis revealed significant relationships (P = 0.005-0.048, correlation coefficients = 0.44-0.84) between LA and LV vortex characteristics (number, size, vortex velocities) and blood pressure as well as end-diastolic volume, LV length, and ejection fraction. CONCLUSIONS Flow patterns in the left heart demonstrated differences related to age, gender, blood pressure, and ventricular geometry. The findings constitute a prerequisite for the understanding of the impact of cardiac disease on intra-cardiac haemodynamics.

Sclerotic Aortic Valve Flow-Sensitive 4-Dimensional Magnetic Resonance Imaging Reveals 3 Distinct Flow-Pattern Changes

We present findings in a 67-year-old male patient who was examined during diagnostic workup because of arrhythmia and pulmonary vein ablation. During transthoracic and transesophageal echocardiography, a nonstenotic, sclerosed aortic valve with slightly reduced area (1.7 cm2) and mild aortic regurgitation were observed. Standard contrast-enhanced magnetic resonance angiography was performed for arterial and venous status. To evaluate the effect of altered valve function on blood flow in the entire aorta, flow-sensitive 4-dimensional magnetic resonance imaging was performed. Data were acquired with cardiac and navigator gating to permit ECG synchronized measurement of 3-directional blood flow in the entire thoracic aorta during free breathing (Magnetom Trio, Siemens, Erlangen, Germany; flip angle =15°, velocity sensitivity =150 cm/s, spatial resolution 3.2×2.1×3.0 mm3, time to echo =3.5 ms, repetition time=5.6 ms, temporal resolution =48.8 ms). Data analysis was performed with a commercially available software package (EnSight, CEI, Apex, NC). …

Myocardial Perfusion Imaging Using OMNISCAN: A Dose Finding Study for Visual Assessment of Stress‐Induced Regional Perfusion Abnormalities

BACKGROUND Different doses of contrast agent are applied for magnetic resonance perfusion studies and mainly semiquantitative approaches have been reported for analysis. We aimed to determine the optimal dose for a visual detection of perfusion defects. METHODS 49 patients (59+/-8 years; 33 male) scheduled for invasive angiography were examined at stress (0.14 mg adenosine/kg body weight/minute) and rest using a TFE-EPI hybrid sequence (Philips ACS NT; 1.5 T). Patients were assigned to three different dose groups of gadodiamide (0.05, 0.1, and 0.15 mmol/kg body weight) injected as a bolus via a peripheral vein. Visual assessment was used to detect a regional reduction of peak signal intensity or speed of contrast agent inflow at stress in comparison to rest. RESULTS Prevalence for coronary artery disease was 67%. The highest diagnostic accuracy was reached for a dose of 0.1 mmol gadodiamide/kg body weight (86% p=nonsignificant vs. 0.15 and 0.05 mmol gadodiamide/kg). At this dose, no major artifacts related to the contrast agent were found. CONCLUSIONS Visual assessment of myocardial perfusion using a high-flow rate contrast agent bolus injection and a TFE-EPI sequence can be best achieved with a dose of gadodiamide 0.1 mmol/kg bodyweight.

Magnetic resonance tissue phase mapping: Analysis of age-related and pathologically altered left ventricular radial and long-axis dyssynchrony

To employ magnetic resonance tissue phase mapping (TPM) for the assessment of age‐related left ventricular (LV) synchrony of radial and long‐axis motion in healthy volunteers and in hypertensive heart disease, dilated cardiomyopathy (DCM), and left bundle branch block (LBBB).

Evidence of Myocardial Edema in Patients With Nonischemic Dilated Cardiomyopathy

Nonischemic dilated cardiomyopathy (DCM) is associated with high mortality and morbidity. Cardiovascular magnetic resonance allows for the noninvasive assessment of function, morphology, and myocardial edema. Activation of inflammatory pathways may play an important role in the etiology of chronic DCM and may also be involved in the disease progression.

Three-directional acceleration phase mapping of myocardial function†

An optimized acceleration encoded phase contrast method termed “acceleration phase mapping” for the assessment of regional myocardial function is presented. Based on an efficient gradient waveform design using two‐sided encoding for in vivo three‐directional acceleration mapping, echo and repetition times TE = 12–14 ms and TR = 15–17 ms for low accelerations sensitivity aenc = 5–8 m/s2 were achieved. In addition to phantom validation, the technique was applied in a study with 10 healthy volunteers at 1.5T and 3T to evaluate its feasibility to assess regional myocardial acceleration at 1.5T and 3T. Results of the acceleration measurements were compared with the temporal derivative of myocardial velocities from three‐directional velocity encoded standard phase contrast MRI in the same volunteers. The feasibility to assess myocardial acceleration along the radial, circumferential, and longitudinal direction of the left ventricle was demonstrated. Despite improved signal‐to‐noise‐ratio at 3T (34% increase compared with 1.5T), image quality with respect to susceptibility artifacts was better 1.5T compared with 3T. Analysis of global and regional left ventricular acceleration showed characteristic patterns of systolic and diastolic acceleration and deceleration. Comparisons of directly measured and derived myocardial acceleration dynamics over the cardiac cycle revealed good correlation (r = 0.45–0.68, P < 0.01) between both methods. Magn Reson Med, 2011.

Comprehensive 4-Dimensional Magnetic Resonance Flow Analysis After Successful Heart Transplantation Resolves Controversial Intraoperative Findings and Reveals Complex Hemodynamic Alterations

We present findings in a 68-year-old man listed for heart transplantation (T status, which is similar to US status 1B) who suffered from long-term heart failure due to dilative cardiomyopathy. After recurrent cardiac decompensation, he was supported with a left ventricular assist device (Synergy, CircuLite, Saddle Brook, NJ).1 After 17 weeks of support, the pump had to be deactivated because of recurrent system failure and thromboembolic events. As a consequence, he was registered as a high-urgency patient and had to wait for another 16 weeks before an organ became available. Orthotopic heart transplantation using the bicaval technique combined with explantation of the left ventricular assist device was uneventful.2,3 Intraoperatively, 3 additional procedures had to be performed: (1) A patch repair of the upper right pulmonary vein was performed after explantation of the left atrial cannula of the left ventricular assist device; (2) a significant discrepancy in the diameters of the native and the transplanted ascending aorta (34 versus 24 mm) made a tapered diameter reduction in the aortic anastomosis necessary; and (3) the donor pulmonary trunk was directly connected to the branching point of the left and right pulmonary arteries. Immediately after heart transplantation and while still in the operating room, the patient was examined by transesophageal echocardiography and pulmonary artery catheterization (Swan-Ganz catheter, Edwards Lifesciences Corp, Irvine, CA). The catheter measurement revealed an elevated systolic pressure gradient in the pulmonary artery of 10 mm Hg, indicative of a pulmonary stenosis; however, this was not supported by transesophageal echocardiography or other hemodynamic data (central venous pressure, pressure in the right ventricle, and cardiac output). After a smooth intraoperative course, the patient made an uncomplicated recovery and was discharged from the hospital within 30 days after heart transplantation. All predischarge examinations, including transthoracic echocardiography, chest radiographs, laboratory …