Impact of Advanced Modeled Iterative Reconstruction on Coronary Artery Calcium Quantification.

RATIONALE AND OBJECTIVES: To evaluate the influence of advanced modeled iterative reconstruction (ADMIRE) on the coronary artery calcium (CAC) scores by computed tomography (CT). MATERIALS AND METHODS: Sixty patients underwent CAC imaging with dual-source 192-slice CT. Agatston, volume and mass score were calculated from filtered back projection (FBP) and iterative reconstructions with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparisons of CAC values and the difference ratio among different ADMIRE groups using FBP as reference. RESULTS: The median Agatston score (range) using FBP was 115 (0.1-3047) and significantly decreased with incremental ADMIRE levels 1-5: 96 (0.1-2813), 91 (0-2764), 87 (0-2699), 80 (0-2590), 70 (0-2440); all P < 0.001. In comparison with FBP Agatston, volume and mass scores significantly decreased with increasing ADMIRE levels 1-5 (P < 0.001): from -12% to -39%, from -14% to -41%, and from -13% to -40%, respectively. In four patients with low calcium burden, the use of ADMIRE 2 or higher resulted in the disappearance of calcium that was detectable using FBP or ADMIRE 1. The decrease of CAC in high-level ADMIRE resulted in a reassignment to a lower Agatston risk group in 27%. CONCLUSIONS: ADMIRE causes a substantial reduction of the CAC scores measured by cardiac CT, which leads to an underestimation of cardiovascular risk scores in some patients.

Prognostic value of cerebral injury following transfemoral aortic valve implantation.

AIMS: To evaluate the impact of serological, imaging and clinical measures of cerebral injury on patient self-sufficiency and survival after transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS: Before and three days after TAVI, neuron-specific enolase (NSE), cerebral diffusion-weighted magnetic resonance imaging (DW-MRI) and neurological performance utilising National Institutes of Health Stroke Scale (NIHSS) were assessed. Self-sufficiency was determined with established score systems (instrumental activities of daily living score, Barthel Index). Parameters of cerebral injury were investigated for their impact on self-sufficiency and all-cause mortality after 30 days and one year. Sixty-one patients were enrolled (logistic EuroSCORE: 26.4±18.1, STS score: 7.9±5.7), of whom 39 completed the imaging protocol. The incidences of NSE increase, new embolic events in DW-MRI, and neurological deficit early after TAVI were 52.4%, 71.8% and 6.6%, respectively. The degree of concomitant comorbidities, reflected by higher risk scores, had significant impact on outcome. Plasma levels of NSE and new emboli in DW-MRI were neither related to self-sufficiency nor to survival one year after TAVI. CONCLUSIONS: In this observational pilot study, "silent" cerebral injury is neither related to dependent lifestyle nor to mortality during the first year after TAVI. However, long-term follow-up is needed to elucidate fully the impact of silent stroke. Clinical trials number: NCT00883285.

Prognostic value of cerebral injury following transfemoral aortic valve implantation.

Aims: To evaluate the impact of serological, imaging and clinical measures of cerebral injury on patient self-sufficiency and survival after transcatheter aortic valve implantation (TAVI). Methods and results: Before and three days after TAVI, neuron-specific enolase (NSE), cerebral diffusion-weighted magnetic resonance imaging (DW-MRI) and neurological performance utilising National Institutes of Health Stroke Scale (NIHSS) were assessed. Self-sufficiency was determined with established score systems (instrumental activities of daily living score, Barthel Index). Parameters of cerebral injury were investigated for their impact on self-sufficiency and all-cause mortality after 30 days and one year. Sixty-one patients were enrolled (logistic EuroSCORE: 26.4±18.1, STS score: 7.9±5.7), of whom 39 completed the imaging protocol. The incidences of NSE increase, new embolic events in DW-MRI, and neurological deficit early after TAVI were 52.4%, 71.8% and 6.6%, respectively. The degree of concomitant comorbidities, reflected by higher risk scores, had significant impact on outcome. Plasma levels of NSE and new emboli in DW-MRI were neither related to self-sufficiency nor to survival one year after TAVI. Conclusions: In this observational pilot study, "silent" cerebral injury is neither related to dependent lifestyle nor to mortality during the first year after TAVI. However, long-term follow-up is needed to elucidate fully the impact of silent stroke. Clinical trials number: NCT00883285.

Risk and fate of cerebral embolism after transfemoral aortic valve implantation: a prospective pilot study with diffusion-weighted magnetic resonance imaging.

OBJECTIVES: The aim of this study was prospective investigation of silent and clinically apparent cerebral embolic events and neurological impairment after transfemoral aortic valve implantation (TAVI). BACKGROUND: TAVI is a novel therapeutic approach for multimorbid patients with severe aortic stenosis. We investigated peri-interventional cerebral embolism with diffusion-weighted magnetic resonance imaging (DW-MRI) and its relationship to clinical and serologic parameters of brain injury. METHODS: Cerebral DW-MRI was performed before, directly, and 3 months after TAVI with the current third-generation self-expanding CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis. At the timepoints of the serial MRI studies, focal neurological impairment was assessed according to the National Institutes of Health Stroke Scale (NIHSS), and serum concentration of neuron-specific enolase (NSE), a marker of the volume of brain tissue involved in an ischemic event, were determined. RESULTS: Thirty patients were enrolled; 22 completed the imaging protocol. Three patients (10%) had new neurological findings after TAVI, of whom only 1 (3.6%) had a permanent neurological impairment. Of the 22 TAVI patients with complete imaging data, 16 (72.7%) had 75 new cerebral lesions after TAVI presumed to be embolic. The NIHSS and NSE were not correlated with DW-MRI lesions. CONCLUSIONS: The incidence of clinically silent peri-interventional cerebral embolic lesions after TAVI is high. However, in this cohort of 30 patients, the incidence of persistent neurological impairment was low. (Incidence and Severity of Silent and Apparent Cerebral Embolism After Conventional and Minimal-invasive Transfemoral Aortic Valve Replacement; NCT00883285).

Incidence and predictors of silent cerebral embolism during pulmonary vein catheter ablation for atrial fibrillation.

AIMS: Left atrial catheter ablation of the pulmonary veins (PV) has evolved as an important therapeutic option for the treatment of atrial fibrillation (AF). We aimed to investigate the incidence and predictors of silent cerebral embolism associated with PV catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI). METHODS AND RESULTS: We performed a prospective analysis of 53 consecutive patients with persistent or paroxysmal AF that underwent PV ablation and post-procedural cerebral MRI 1 day after lasso catheter-guided ostial PV ablation. Patients were analysed for possible demographical, medical, echocardiographical, and procedural predictors of embolic events. A mean of 3.5 +/- 0.5 PVs were ablated per patient. In six patients, DW-MRI depicted new clinically silent microembolism after PV ablation (11%). The number of ineffective medical antiarrhythmic agents prior to ablation procedure was significantly higher in the embolism group (3.3 +/- 0.5 vs. 2.2 +/- 1.4, P = 0.014). Coronary heart disease (CAD) was more frequent in patients with cerebral embolisms (33 vs. 2%, P = 0.031); left ventricular volume (130 +/- 12 vs. 103 +/- 26 mL, P = 0.002), and septal wall thickness (13.0 +/- 1.4 vs. 7.9 +/- 4.8 mm, P = 0.025) were significantly increased. CONCLUSION: This study shows a high incidence of silent micro-embolic events after PV ablation. CAD, left ventricular dilatation, and hypertrophy were potential predictors of this complication.

High-resolution myocardial stress perfusion at 3 T in patients with suspected coronary artery disease.

To implement a high-resolution first-pass myocardial perfusion imaging protocol (HRPI) at 3 T, and to evaluate the feasibility, image quality and accuracy of this approach prospectively in patients with suspected CAD. We hypothesized that utilizing the gain in SNR at 3 T to increase spatial resolution would reduce partial volume effects and subendocardial dark rim artifacts in comparison to 1.5 T. HRPI studies were performed on 60 patients using a segmented k-space gradient echo sequence (in plane resolution 1.97 x 1.94 mm(2)). Semiquantitative assessment of dark rim artifacts was performed for the stress studies on a slice-by-slice basis. Qualitative visual analysis was compared to quantitative coronary angiography (QCA) results; hemodynamically significant CAD was defined as stenosis >or=70% at QCA. Dark rim artifacts appeared in 108 of 180 slices (average extent 1.3 +/- 1.2 mm representing 11.8 +/- 10.8% of the transmural myocardial thickness). Sensitivity, specifity, and test accuracy for the detection of significant CAD were 89%,79%, and 85%. HRPI studies at 3 T are feasible in a clinical setting, providing good image quality and high accuracy for detection of significant CAD. The presence of dark rim artifacts does not appear to represent a diagnostic problem when using a HRPI approach.