Association of left pulmonary vein trunk and subclinical atrial fibrillation in patients with cardiac implantable electronic device.

The relationship between subclinical atrial fibrillation (SCAF) and left pulmonary vein anatomy is unknown. This study sought to investigate whether left pulmonary vein trunk predict the development of SCAF in patients with cardiac implantable electronic device (CIED). We also examined the relationship between the duration of SCAF and left pulmonary vein trunk. We retrospectively enrolled 162 patients who underwent implantation of dual-chamber CIEDs and follow-up by remote monitoring system. Computed tomography was used to measure the length of the left pulmonary vein. During median follow up of 2.7 years, the episodes of > 6 min and > 24 h SCAF were observed in 61 (37.7%) and 24 (14.8%) patients, respectively. The diagnosis of sinus node disease (HR: 3.66 [2.06-6.52], P < 0.01 and HR: 2.68 [1.09-6.62], P = 0.04) and left atrial diameter (HR: 1.04 [1.00-1.07], P = 0.04 and HR: 1.05 [1.00-1.10], P = 0.04) were independent predictors for > 6 min and > 24 h SCAF, respectively. Length of the left pulmonary vein trunk was an independent predictor for > 6 min SCAF (HR: 1.06 [1.02-1.10], P < 0.01), but not for > 24 h SCAF (P = 0.06). Sinus node disease, size of the left atrium and length of the left pulmonary vein trunk were related to SCAF. The left pulmonary vein trunk might especially contribute as a trigger rather than as a driver of development of atrial fibrillation.

[Development of Auto Dense-breast Classification on Mammography Images Using Image Similarity].

PURPOSE: In Japan, radiologists perform qualitative visual classification to define four categories of mammary gland density. However, an objective estimation of mammary gland density is necessary. To address this, we developed an automatic classification software using image similarity. METHODS: We prepared 741 cases of mediolateral oblique images (MLO) for evaluation, and they were diagnosed as normal among the mammography images taken at our hospital. Image matching was performed using the evaluation images and an image database for breast density determination. In this study, the image similarity used zero normalized cross-correlation (ZNCC) as an index. In addition, if the breast thickness is less than 30 mm and each breast density category ZNNC has the same value, the category is evaluated on the fat side. We compared the results of qualitative visual classification and automatic classification methods to assess consistency. RESULTS: The agreement with the subjective breast composition classification was 78.5%, and the weighted kappa coefficient was 0.98. One mismatched case was evaluated on the higher density side with the same ZNCC value between categories and a breast thickness greater than 30 mm. CONCLUSION: Image similarity provides an excellent estimation of quantification of breast density. This system could contribute to improving the efficiency of the mammography screening system.

Patient radiation exposure dose reduction using stent-enhanced image processing in percutaneous coronary intervention.

We investigated the reduction in patient radiation exposure dose during percutaneous coronary intervention (PCI) by stent enhancement processing. We examined the effects of dose reduction based on the image quality of stent enhancement processing using a purpose-built dynamic phantom. We evaluated the image contrast (IC) of the stent in stent-enhanced images (SVref), digital angiography (DA), and stent-enhanced images with a 20%, 40%, and 60% lower imaging doses (SV20, SV40, and SV60). We visually evaluated graininess and stent shape using the mean opinion score (MOS) and retrospectively evaluated the acquisition duration of stent enhancement in PCI cases; finally, we estimated the decrease in patient radiation exposure due to stent enhancement. The image contrast of SVref at phantom thicknesses of 20 cm was 51.25 ± 3.82, while the image contrast of DA was significantly reduced at 14.90 ± 1.57 (p < 0.05). We observed a significant decrease in the MOS of graininess in SV60 and MOS of stent shape in DA (p < 0.05). Furthermore, the average imaging duration for stent enhancement using PCI was 22.65 ± 7.43 s, and the maximum imaging duration was 68.07 s. We hypothesize that patient radiation exposure dose can be reduced by up to 60.17 mGy by lowering the imaging dose during the stent enhancement process. Stent enhancement processing improves the visibility of stent images, and can reduce radiation exposure by approximately 40% during confirmation imaging of stents. Our study contributes to the reduction of radiation exposure dose for operators and patients in PCI.