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Background Despite the impressive results of the large CRT trials, it has been observed that, on an individual basis, about 30% of patients fail to respond to cardiac resynchronization therapy (CRT). The evaluation of left ventricular (LV) dyssynchrony, myocardial scar, and coronary venous anatomy by image subtraction in Late Iodine Enhancement Computed Tomography (LIE-CT) has the potential to comprehensively characterize non-responders. Purpose To assess the feasibility and the utility of image subtraction in LIE-CT in CRT patients and compare findings between responders and non-responders. Methods Monocentric prospective study of CRT patients at least 6 months after implantation who underwent post-procedural CT between March and October 2018. CRT-responders were defined as patients with an absolute increase in LV ejection fraction >5%. CT-derived residual global and segmental dyssynchrony metrics, extent and location of myocardial scar, coronary venous anatomy, and position of LV lead relative to scar and segment of latest mechanical contraction were analyzed. Results Among the 29 patients (mean age 71±12 years; 72% men), 18 were responders (62%). All CT metrics evaluating residual dyssynchrony such as wall motion indexand wall thickness indexwere worse in non-responders (p Wall Motion and LIE-CT Conclusion Image subtraction in LIE-CT in patients who had CRT is feasible and allows better characterization of CRT-non-responders, who have a greater amount of residual dyssynchrony than responders. Distribution of fibrosis in relation to the LV lead and presence of alternative venous branches may help patient management.

Delayed myocardial enhancement and diagnosis of acute coronary syndrome with normal coronarography Cardiac MRI in patients with acute coronary syndrome with elevated troponin levels but normal coronarography can now routinely be performed on most MR units. MRI plays an important role in this clinical setting by its ability to detect myocardial infarction in patients with normal coronarography or suggest a different, potentially severe, alternate diagnosis such as myocarditis or takotsubo cardiomyopathy.

Cardiac diffusion MRI of recent and chronic myocardial infarction: preliminary results Purpose. To use diffusion weighted MR imaging (DWI), a technique routinely used in patients with stroke, for diagnosis of myocardial infarction (MI). Materials and methods. A breath hold ECG gated DWI sequence (b=300 sec/mm 2 ) was developped and applied to 7 patients with recent MI (3-15 days), 3 patients with chronic MI (> 6 months) and 4 patients with valvular heart disease without MI (control cases). DWI data were correlated to T2W, first pass perfusion and delayed enhancement data. Results. In all patients with recent MI, DWI showed an area of increased signal with reduction of ADC relative to normal myocardium. Hyperintense lesion on DWI corresponded to areas of delayed enhancement. The diffusion images were normal in patients with chronic MI or no MI. Conclusion. Even though no animal model or other reference method is available, these preliminary results indicate that DWI could assist clinicians in detecting recent MI.

Resume La rapidite d’acquisition des nouvelles generations de TDM helicoidale en synchronisation retrospective et l’obtention d’images isotropiques ont donne une avance provisoire a cette technique sur l’IRM. Provisoire, car les nouvelles techniques de balayage de l’espace de Fourier permettent de s’affranchir actuellement des problemes des mouvements respiratoires et cardiaques grâce a des acquisitions tres rapides en apnee, avec une resolution spatiale presque aussi bonne qu’en TDM. Le mythe des acquisitions plus difficiles a programmer en IRM, car dans le plan des coronaires et non dans le plan axial de la TDM, est faux a partir du moment ou l’on connait le trajet des trois arteres coronaires principales. Dans la course a l’imagerie non invasive des arteres coronaires, les deux techniques se rapprochent l’une de l’autre, tout en apportant des informations cliniquement pertinentes.

Cardiac output relies on an appropriate contractile function. It is mandatory to recognize kinetic alterations of the myocardium and to precise their extent (i.e. segmental, regional or global), to quantify their consequences on the function of the cardiac pump, and to assess if the underlying disease is reversible or fixed.

The recent developments of synchronized cardiac MRI are a unique opportunity for the radiology community to integrate cardiac imaging. This educational aticle aims to help radiologists and technicians to obtain cardiac planes comparable to those of cardiac ultrasound and gated SPECT. Of course, cardiac planes described herein for MRI also apply to multi-detector CT.