There are only limited data on the impact of device-related artifacts on image quality in cardiovascular magnetic resonance imaging (CMR) in patients with pacemakers (PM). Adenosine stress perfusion, T1-weighted imaging and flow measurement as well as valve characterization have not been evaluated previously concerning artifact burden. We aimed to assess image quality in all routinely used CMR sequences. We analyzed 2623 myocardial segments in CMR scans of 61 patients with MR conditional PM (mean age 72.1 ± 11.5 years), 23 (37.7%) with right sided, 38 (62.3%) with left-sided devices. There were no relevant artifacts in patients with right-sided devices irrespective of the imaging sequence. In left-sided implants no PM-induced artifacts were found in first pass perfusion sequence, flow analysis and T1 weighted imaging. Only few patients with left-sided devices showed significant PM-artifacts in aortic (3/38, 7.9%)/mitral (n = 2/38, 5.3%) valve imaging and STIR (n = 3/35, 8.6%). In STIR only 14/805 (1.7%) segments were involved. In left-sided PM SSFP cine sequences had more artifact burden than LGE with 377/1505 (25.0%) vs. 162/1505 (10.8%) myocardial segments involved by relevant artifacts respectively (p < 0.001). Apart from cine and LGE imaging in anterior myocardial segments with left-sided implants presence of MRI conditional pacemakers does not affect CMR image quality in multimodal CMR examinations to a significant extent. Our data supports evidence that reduced image quality does not need to be a major concern in PM patients undergoing CMR.

BackgroundCardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine.MethodsWe retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement.ResultsPacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm.ConclusionAdenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

This was a radiologists' preference study to compare a digital chest radiography system that utilizes a large-area silicon flat-panel detector with conventional radiography for visualizing anatomic regions of the chest. Conventional and digital posteroanterior (PA) and lateral chest radiographs were obtained in 115 patients. The PA and lateral image pairs were compared independently by three radiologists rating the overall appearance, 11 anatomic regions in the PA, and 9 in the lateral views. Statistical analysis was performed with the Wilcoxon signed-rank test with Bonferroni-Holm adjustment (p=0.05). For the PA view, the digital system performed significantly better for the overall appearance and for all anatomic regions except for the peripheral pulmonary vasculature and hilum, where no significant difference was found. For the lateral digital images, the regions trachea, costodiaphragmatic recess, and hilum were rated significantly worse. The regions retrosternal and retrocardiac lung were rated significantly better. The other regions and the overall appearance showed no significant differences. The described digital chest radiography system showed statistically superior visualization of anatomic regions for PA and an ambiguous performance for lateral images as compared with conventional radiography. After changing some image processing parameters for the lateral view, this system may be suitable for digitalization of chest radiography.

Background: Cardiovascular Magnetic Resonance (CMR) imaging with adenosine stress is an important diagnostic tool in patients with known or suspected coronary artery disease (CAD). However, the method is not yet established for CAD patients with pacemakers (PM) in clinical practice. A possible reason is that no recommendations exist for PM setting (paused pacing or asynchronous mode) during adenosine stress. We elaborated a protocol for rhythm management in clinical routine for PM patients that considers heart rate changes under adenosine using a test infusion of adenosine in selected patients. Methods: 47 consecutive patients (mean age 72.3 ± 10,0 years) with MR conditional PM and known or suspected CAD who underwent CMR in clinical routine were studied in this prospective observational study. PM indications were sinus node dysfunction (SND, n = 19; 40,4%), atrioventricular (AV) block (n = 26; 55.3%) and bradyarrhythmia in permanent atrial fibrillation (AF, n = 2; 4.3%). In patients with SND, normal AV-conduction and resting HR >45 bpm at the time of CMR and in AF the PM was deactivated for the scan. In intermittent AV-block a test infusion of adenosine was given prior to the scan. All patients with permanent higher degree sinuatrial or AV-block or deterioration of AV-conduction in the adenosine test were paced asynchronously during CMR, in patients with preserved AV-conduction under adenosine the pacemaker was deactivated. CMR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Results: The adenosine test was able to differentiate between mandatory PM stimulation during CMR and safe deactivation of the device. In patients with permanent sinuatrial or AV-block (n = 11; 23.4%) or deterioration of AV conduction in the adenosine test (n = 5, 10.6%) asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm, no competitive stimulation was seen during the scan. 10 of 15 (66,7%) patients with intermittent AV-block showed preserved AV-conduction under adenosine. As in SND and AF deactivation of the PM showed to be safe during CMR, no bradycardia was observed.

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