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Background Clinical utility of myocardial delayed-enhancement CT is currently limited because of relatively poor contrast-to-noise ratio (CNR) and artifacts. Targeted spatial-frequency filtration (TSFF) is a hybrid algorithm of half- and full-scan reconstruction that can achieve both high temporal resolution and improved stability of myocardial signal. Objective The purpose of this study was to evaluate image quality of delayed-enhancement CT using TSFF with image averaging and its reproducibility in infarct assessment in comparison with conventional half-scan reconstruction (HALF). Methods Forty patients with suspected coronary artery disease underwent delayed-enhancement CT with HALF and TSFF using dual-source CT. Two blinded readers independently determined the presence and size of delayed enhancement. Image quality, signal-to-noise ratio and CNR were assessed. The presence of delayed enhancement on CT was compared with magnetic resonance imaging in 12 patients. Results TSFF with averaging of 4 image stacks acquired during 1 breathhold demonstrated significantly better image quality compared with HALF. Good left ventricular lumen-myocardium contrast was consistently achieved with TSFF in patients who received iodine dose of >600mgI/kg. The signal-to-noise ratio and CNR were 11.3 ± 4.2 and 4.5 ± 1.6 by TSFF, being significantly higher than those by HALF (7.9 ± 2.9 and 3.3 ± 1.8; P < .01 for both). Interobserver reproducibility of infarct sizing was markedly improved by using TSFF instead of HALF (intraclass correlation coefficient: 0.86 vs 0.50). Agreement with magnetic resonance imaging by kappa statistics was 0.85 with TSFF and 0.74 with HALF. Conclusions TSFF with image averaging can significantly improve image quality of delayed-enhancement CT and considerably enhances interobserver reproducibility of infarct sizing. [ABSTRACT FROM AUTHOR]

Type B acute aortic dissection (AAD) is often successfully managed with medical therapy, with a lower mortality rate, compared with type A AAD. Although the number of AAD patients complicated with atrial fibrillation (AF) has increased, reflecting an aging society, there have only been a few reports regarding the association of AAD and AF. Furthermore, there is no consensus on anticoagulation therapy in ADD patients complicated with AF, despite the importance of anticoagulation therapy in AF treatment. Here, we discuss a 79-year-old man with type B AAD and chronic AF complicated with the rapid left atrial appendage (LAA) thrombus formation after discontinuation of anticoagulation therapy. Emergent contrast-enhanced computed tomography revealed type B AAD with a partially thrombosed false lumen from the bifurcation of the aorta and the left subclavian artery to above the diaphragm. Ulcer-like projection was observed in the proximal thrombosed false lumen. Ten days after discontinuation of anticoagulation therapy, LAA thrombus was detected on contrast-enhanced computed tomography, which was not observed on admission. After anticoagulation therapy was resumed, the LAA thrombus disappeared, but the partially thrombosed false lumen was enlarged. The second discontinuation of anticoagulation therapy stabilized the dissected aorta and did not cause recurrence of LAA thrombus. In conclusion, clinicians need to balance the prevention of LAA thrombus formation with the complete thrombosis of a false lumen in patients with AAD and AF. [ABSTRACT FROM AUTHOR]