Mihály Károlyi

Multimodality Imaging of Giant Right Coronary Aneurysm and Postsurgical Coronary Artery Inflammation

A 52-year-old former recreational marathon runner with a history of permanent atrial fibrillation was referred to our institution because of fatigue and shortness of breath. His 12-lead ECG indicated atrial fibrillation with incomplete right bundle-branch block and inferolateral T-wave inversions (Figure 1). The chest x-ray showed an abnormal structure with a circular silhouette at the projection of the right atrium in the anterior-posterior view (Figure 2). Transthoracic echocardiography revealed a vascular tubular structure adjacent to the atrioventricular groove (Figure 3A and 3B and Movies I and II in the online-only Data Supplement). Subsequently, we performed a coronary computed tomography angiography (CCTA) using a 256-slice multidetector-row CT (Philips Brilliance iCT, Best, The Netherlands) with a tube voltage of 100 kV and a tube current of 300 mA. Because of the atrial fibrillation (mean heart rate, 57 bpm; range, 45–110 bpm), an arrhythmia detection algorithm was used during the prospective ECG-triggered image acquisition. The CCTA depicted a normal left coronary system with no signs of atherosclerosis. The ostium of the right coronary artery (RCA) was dilated (10×8 mm), and the proximal segment of the vessel formed a giant aneurysm (Figure 4A and 4B). The location of the aneurysm was noted to be anterior to the right atrium, adjacent to the atrioventricular groove, and its size measured 62×60×86 mm (Figure 4D–4F). Distal to the aneurysm, the extremely tortuous RCA remained enlarged (12–14 mm) and showed a fistulous communication with the coronary sinus (Figure 4C). The length of the whole RCA was ≈80 cm along its centerline. Subsequent invasive coronary angiography confirmed the CCTA findings (Movies III and IV in the online-only Data Supplement). Surgery was performed to repair the RCA and to stop …

Iterative model reconstruction reduces calcified plaque volume in coronary CT angiography

OBJECTIVE To assess the impact of iterative model reconstruction (IMR) on calcified plaque quantification as compared to filtered back projection reconstruction (FBP) and hybrid iterative reconstruction (HIR) in coronary computed tomography angiography (CTA). METHODS Raw image data of 52 patients who underwent 256-slice CTA were reconstructed with IMR, HIR and FBP. We evaluated qualitative, quantitative image quality parameters and quantified calcified and partially calcified plaque volumes using automated software. RESULTS Overall qualitative image quality significantly improved with HIR as compared to FBP, and further improved with IMR (p<0.01 all). Contrast-to-noise ratios were improved with IMR, compared to HIR and FBP (51.0 [43.5-59.9], 20.3 [16.2-25.9] and 14.0 [11.2-17.7], respectively, all p<0.01) Overall plaque volumes were lowest with IMR and highest with FBP (121.7 [79.3-168.4], 138.7 [90.6-191.7], 147.0 [100.7-183.6]). Similarly, calcified volumes (>130 HU) were decreased with IMR as compared to HIR and FBP (105.9 [62.1-144.6], 110.2 [63.8-166.6], 115.9 [81.7-164.2], respectively, p<0.05 all). High-attenuation non-calcified volumes (90-129 HU) yielded similar values with FBP and HIR (p=0.81), however it was lower with IMR (p < 0.05 both). Intermediate- (30-89 HU) and low-attenuation (<30 HU) non-calcified volumes showed no significant difference (p=0.22 and p=0.67, respectively). CONCLUSIONS IMR improves image quality of coronary CTA and decreases calcified plaque volumes.

High Risk Plaque Features on Coronary CT Angiography

Coronary computed tomography angiography (CCTA) is a non-invasive imaging technique that can detect, characterize and quantify coronary atherosclerotic plaques in routine clinical settings. The distinct morphological features of vulnerable plaques and stable lesions provide an opportunity for CCTA to identify high-risk plaque features and guide stratified therapeutic interventions. Morphological plaque characteristics, such as large plaque volume, positive remodelling, low CT attenuation, spotty calcification and the napkin-ring sign have been linked to elevated risk of acute coronary syndrome. Recent advances in computational fluid dynamics enabled functional plaque assessment through endothelial shear stress and lesion specific fractional flow reserve calculation. The comprehensive, morphological and functional plaque assessment may improve the identification of vulnerable coronary lesions.

Image Quality of Prospectively ECG-Triggered Coronary CT Angiography in Heart Transplant Recipients

OBJECTIVE Cardiac allograft vasculopathy (CAV) is among the top causes of death 1 year after heart transplantation (HTx). Coronary CT angiography (CTA) is a potential alternative to invasive imaging in the diagnosis of CAV. However, the higher heart rate (HR) of HTx recipients prompts the use of retrospective ECG-gating, which is associated with higher radiation dose, a major concern in this patient population. Therefore, we sought to evaluate the feasibility and image quality of low-radiation-dose prospectively ECG-triggered coronary CTA in HTx recipients. MATERIALS AND METHODS In total, 1270 coronary segments were evaluated in 50 HTx recipients and 50 matched control subjects who did not undergo HTx. The control subjects were selected from our clinical database and were matched for age, sex, body mass index, HR, and coronary dominance. Scans were performed using 256-MDCT with prospective ECG-triggering. The degree of motion artifacts was evaluated on a per-segment basis on a 4-point Likert-type scale. RESULTS The median HR was 74.0 beats/min (interquartile range [IQR], 67.8-79.3 beats/min) in the HTx group and 73.0 beats/min (IQR, 68.5-80.0 beats/min) in the matched control group (p = 0.58). In the HTx group, more segments had diagnostic image quality compared with the control group (624/662 [94.3%] vs 504/608 [82.9%]; p < 0.001). The mean effective radiation dose was low in both groups (3.7 mSv [IQR, 2.4-4.3 mSv] in the HTx group vs 4.3 mSv [IQR, 2.6-4.3 mSv] in the control group; p = 0.24). CONCLUSION Prospectively ECG-triggered coronary CTA examinations of HTx recipients yielded diagnostic image quality with low radiation dose. Coronary CTA is a promising noninvasive alternative to routine catheterization during follow-up of HTx recipients to diagnose CAV.