A non-contrast self-navigated 3-dimensional MR technique for aortic root and vascular access route assessment in the context of transcatheter aortic valve replacement: proof of concept.

OBJECTIVES: Due to the high prevalence of renal failure in transcatheter aortic valve replacement (TAVR) candidates, a non-contrast MR technique is desirable for pre-procedural planning. We sought to evaluate the feasibility of a novel, non-contrast, free-breathing, self-navigated three-dimensional (SN3D) MR sequence for imaging the aorta from its root to the iliofemoral run-off in comparison to non-contrast two-dimensional-balanced steady-state free-precession (2D-bSSFP) imaging. METHODS: SN3D [field of view (FOV), 220-370 mm(3); slice thickness, 1.15 mm; repetition/echo time (TR/TE), 3.1/1.5 ms; and flip angle, 115°] and 2D-bSSFP acquisitions (FOV, 340 mm; slice thickness, 6 mm; TR/TE, 2.3/1.1 ms; flip angle, 77°) were performed in 10 healthy subjects (all male; mean age, 30.3 ± 4.3 yrs) using a 1.5-T MRI system. Aortic root measurements and qualitative image ratings (four-point Likert-scale) were compared. RESULTS: The mean effective aortic annulus diameter was similar for 2D-bSSFP and SN3D (26.7 ± 0.7 vs. 26.1 ± 0.9 mm, p = 0.23). The mean image quality of 2D-bSSFP (4; IQR 3-4) was rated slightly higher (p = 0.03) than SN3D (3; IQR 2-4). The mean total acquisition time for SN3D imaging was 12.8 ± 2.4 min. CONCLUSIONS: Our results suggest that a novel SN3D sequence allows rapid, free-breathing assessment of the aortic root and the aortoiliofemoral system without administration of contrast medium. KEY POINTS: • The prevalence of renal failure is high among TAVR candidates. • Non-contrast 3D MR angiography allows for TAVR procedure planning. • The self-navigated sequence provides a significantly reduced scanning time.

Cardiac MRI: evaluation of phonocardiogram-gated cine imaging for the assessment of global und regional left ventricular function in clinical routine.

OBJECTIVES: To validate a phonocardiogram (PCG)-gated cine imaging approach for the assessment of left ventricular (LV) function. METHODS: In this prospective study, cine MR imaging of the LV was performed twice in 79 patients by using retrospectively PCG- and retrospectively ECG-gated cine SSFP sequences at 1.5 T. End-diastolic volumes (EDV), end-systolic volumes (ESV), stroke volumes (SV), ejection fraction (EF), muscle mass (MM), as well as regional wall motion were assessed. Subgroup analyses were performed for patients with valvular defects and for patients with dysrhythmia. RESULTS: PCG-gated imaging was feasible in 75 (95%) patients, ECG-gating in all patients. Excellent correlations were observed for all volumetric parameters (r > 0.98 for all variables analysed). No significant differences were observed for EDV (-0.24 ± 3.14 mL, P = 0.5133), ESV (-0.04 ± 2.36 mL, P = 0.8951), SV (-0.20 ± 3.41 mL, P = 0.6083), EF (-0.16 ± 1.98%, P = 0.4910), or MM (0.31 ± 4.2 g, P = 0.7067) for the entire study cohort, nor for either of the subgroups. PCG- and ECG-gated cine imaging revealed similar results for regional wall motion analyses (115 vs. 119 segments with wall motion abnormalities, P = 0.3652). CONCLUSION: The present study demonstrates that PCG-gated cine imaging enables accurate assessment of global and regional LV function in the vast majority of patients in clinical routine. KEY POINTS: Phonocardiogram-gating is an alternative to electrocardiographic-gating in cardiac MR. Phonocardiogram-gated imaging allows reliable assessment of global and regional left-ventricular function. Phonocardiogram-gating is feasible in patients with valvular lesions or cardiac dysrhythmia. Because phonocardiogram-gating is insensitive to magneto-hydrodynamic effects, it is suitable for ultra-high field.

Focused echocardiographic evaluation in life support and peri-resuscitation of emergency patients: a prospective trial.

PURPOSE OF THE STUDY: Focused ultrasound is increasingly used in the emergency setting, with an ALS-compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management. PATIENTS, MATERIALS AND METHODS: A prospective observational study in a pre-hospital emergency setting in patients actively undergoing cardio-pulmonary resuscitation or in a shock state. The FEEL protocol was applied by trained emergency doctors, following which a standardised report sheet was completed, including echo findings and any echo-directed change in management. These reports were then analysed independently. RESULTS: A total of 230 patients were included, with 204 undergoing a FEEL examination during ongoing cardiac arrest (100) and in a shock state (104). Images of diagnostic quality were obtained in 96%. In 35% of those with an ECG diagnosis of asystole, and 58% of those with PEA, coordinated cardiac motion was detected, and associated with increased survival. Echocardiographic findings altered management in 78% of cases. CONCLUSIONS: Application of ALS-compliant echocardiography in pre-hospital care is feasible, and alters diagnosis and management in a significant number of patients. Further research into its effect on patient outcomes is warranted.

Focused emergency echocardiography: lifesaving tool for a 14-year-old girl suffering out-of-hospital pulseless electrical activity arrest because of cardiac tamponade.

Cardiac arrest presenting as pulseless electrical activity (PEA) is associated with poor outcome. Its major underlying causes (e.g. cardiac tamponade, pulmonary embolism, tension pneumothorax or hypovolaemia) are difficult to detect reliably in an out-of-hospital setting. We here present a case of a 14-year-old girl suffering from PEA because of cardiac tamponade 4 weeks after surgical closure of a ventricular septal defect. Immediate focused echocardiography on scene by an emergency physician showed a large pericardial effusion that had led to cardiac tamponade and finally to a PEA cardiac arrest. Immediate pericardiocentesis was carried out. The girl progressed to complete neurological recovery. This case report demonstrates that focused emergency echocardiography may be useful for the diagnosis of pericardial tamponade leading to cardiac arrest and this diagnosis can be made out-of-hospital by an appropriately trained physician.