Search

Background Myocardial thickness is particularly thick at the ridge between the left pulmonary vein (PV) and the left atrial appendage (LAA) by dissection. We investigated whether atrial fibrillation (AF) ablation outcome was influenced by altering ablation strategies according to the thickness of the PV–LAA ridge using preprocedural multidetector computed tomography (MDCT). Methods and results Patients with AF scheduled for extensive encircling circumferential pulmonary vein isolation (EEPVI) (110 patients) were divided into 2 groups. In the nonmodulation group (32 patients), EEPVI lines were created using a 3.5-mm tip irrigated catheter at a maximum power of 30 W for 20–30 s at each site. In the modulation group (78 patients), ablation was extended (40–60 s) at the PV–LAA ridge if its thickness was >4.0 mm on MDCT examination. Extended ablation at the PV–LAA ridge was noted in 37 patients in the modulation group. During 25 ± 9 months of follow-up, recurrence was significantly less in the modulation group than in the nonmodulation group (10% vs. 28%; p = 0.018). Logistic regression analysis showed that modifications in the ablation time and left atrium volume index were independent predictors of arrhythmia-free recovery after ablation. Conclusions Recurrence following EEPVI could be reduced by modifications in the ablation time at the PV–LAA ridge.

Background To figure out the relationship between image noise and contrast noise ratio (CNR) at different tube voltages, using anthropomorphic new-born and 1-year-old phantoms, and to discuss the feasibility of radiation dose reduction, based on the obtained CNR index from image noise. We performed helical scans of the anthropomorphic new-born and 1-year-old phantoms. The CT numbers of the simulated aorta and image noise of the simulated mediastinum were measured; then CNR was calculated on 80, 100, and 120-kVp images reconstructed with filtered back projection (FBP) and iterative reconstruction (IR). We also measured the center and surface dose in the case of CNR of 14 using radio-photoluminescence glass dosimeters. Results The CT number of the simulated aorta was increased with decreasing tube voltage from 120 to 80 kVp (362.5–535.1 HU for the new-born, 358.9–532.6 HU for the 1-year-old). At CNR of 14, the center dose was 0.4, 0.6 and 0.9 mGy at FBP and 0.5, 0.6 and 0.9 mGy at IR and with the new-born phantom acquired at 80, 100 and 120 kVp, respectively. The center dose for FBP image was reduced by 56% at 80 kVp, 34% at 100 kVp for the new-born and 36% at 80 kVp, 22% at 100 kVp for the 1-year-old compared with that at 120 kVp. We obtained a relationship between image noise and CNR at different tube voltages using the anthropomorphic new-born and 1-year-old phantoms. Conclusion The use of index of CNR with low-tube voltage may achieve further radiation dose reduction in pediatric CT examination.

To evaluate the safety and outcome of embolization as treatment for persistent type 2 endoleak (T2EL) occurring after abdominal aortic stent graft implantation. This retrospective study included seven consecutive patients (one female, six males, mean age 72 years, range 66–88 years) with T2EL between January 2011 and September 2012. In all, T2EL was associated with an increase more than 5 mm in the aneurysm. The endoleak cavity or feeding artery was embolized with coils and/or n-butyl cyanoacrylate. Clinical success was defined as regression or stabilization of the aneurysm sac irrespective of residual endoleaks on follow-up CT studies. At the time of T2EL intervention, mean aneurysm sac diameter was 63 mm (range 52–72 mm), and mean increase size of aneurysm sac diameter was 7 mm (range 5–13). Mean follow-up period was 6.0 ± 6.2 months (range 3–18 months). Our technical success rate was 100 %. Clinical success was obtained in 5 (71.4 %) of the seven patients. One patient was embolized three times due to sac expansion. T2EL was treated by transarterial embolization in eight procedures, and one procedure was performed by direct puncture embolization. There were no major complications; two procedures elicited minor complications: transient back pain and muscle weakness of the left lower leg. We suggest embolization was safe and effective treatment, a less invasive treatment option comparison to open repair, as one choice to address T2EL.