Cardiac Computed Tomography Radiomics: A Comprehensive Review on Radiomic Techniques

Radiologic images are vast three-dimensional data sets in which each voxel of the underlying volume represents distinct physical measurements of a tissue-dependent characteristic. Advances in technology allow radiologists to image pathologies with unforeseen detail, thereby further increasing the amount of information to be processed. Even though the imaging modalities have advanced greatly, our interpretation of the images has remained essentially unchanged for decades. We have arrived in the era of precision medicine where even slight differences in disease manifestation are seen as potential target points for new intervention strategies. There is a pressing need to improve and expand the interpretation of radiologic images if we wish to keep up with the progress in other diagnostic areas. Radiomics is the process of extracting numerous quantitative features from a given region of interest to create large data sets in which each abnormality is described by hundreds of parameters. From these parameters datamining is used to explore and establish new, meaningful correlations between the variables and the clinical data. Predictive models can be built on the basis of the results, which may broaden our knowledge of diseases and assist clinical decision making. Radiomics is a complex subject that involves the interaction of different disciplines; our objective is to explain commonly used radiomic techniques and review current applications in cardiac computed tomography imaging.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/

A coronariarendszer komputertomográfiás vizsgálata - Országos Plakk Regiszter és Adatbázis (OPeRA)

INTRODUCTION AND AIM: Coronary computer tomography angiography is a unique non-invasive imaging technique with the capability to provide information regarding plaque quantity, burden and structure. A reliable registry is required to use the data of these examinations in research projects. The difficulty is that registries need double data entry simultaneously to the hospital information system. METHOD: Our registry solves this problem through a structured reporting tool, which generates clinical report and stores all data simultaneously. The automatically generated report is based on international guidelines. RESULTS: Between August 1. 2014 and September 1. 2015 we registered the data of 2866 patients. Coronary plaque was observed in 77.03% of the patients, 33.18% of the plaques were calcified. Severe stenosis was present in 13.71% of the patients. CONCLUSIONS: The structured reporting decreases reporting time, eliminates double data entry related errors. Our goal is to initiate a nationwide, unified registry, the National Plaque Registry and Database. Orv. Hetil., 2017, 158(3), 106-110

Radiomic Features Are Superior to Conventional Quantitative Computed Tomographic Metrics to Identify Coronary Plaques With Napkin-Ring Sign

BACKGROUND: Napkin-ring sign (NRS) is an independent prognostic imaging marker of major adverse cardiac events. However, identification of NRS is challenging because of its qualitative nature. Radiomics is the process of extracting thousands of quantitative parameters from medical images to create big-data data sets that can identify distinct patterns in radiological images. Therefore, we sought to determine whether radiomic analysis improves the identification of NRS plaques. METHODS AND RESULTS: From 2674 patients referred to coronary computed tomographic angiography caused by stable chest pain, expert readers identified 30 patients with NRS plaques and matched these with 30 non-NRS plaques with similar degree of calcification, luminal obstruction, localization, and imaging parameters. All plaques were segmented manually, and image data information was analyzed using Radiomics Image Analysis package for the presence of 8 conventional and 4440 radiomic parameters. We used the permutation test of symmetry to assess differences between NRS and non-NRS plaques, whereas we calculated receiver-operating characteristics' area under the curve values to evaluate diagnostic accuracy. Bonferroni-corrected P0.80. Short- and long-run low gray-level emphasis and surface ratio of high attenuation voxels to total surface had the highest area under the curve values (0.918; 0.894 and 0.890, respectively). CONCLUSIONS: A large number of radiomic features are different between NRS and non-NRS plaques and exhibit excellent discriminatory value

Mellkasiaortastentgraft-beültetések Magyarországon 2012 és 2016 között [Thoracic aortic stentgraft implantations in Hungary from 2012 to 2016]

Thoracic aortic endograft implantation has become a widespread procedure in recent years, yet no report is available about Hungarian outcomes. Examination of our results is crucial to define further treatment strategies. Analysis of perioperative data from Hungarian thoracic endograft implantations based on the experience of 5 years is presented. Our retrospective, multicentric study analysed voluntarily reported data from all Hungarian institutions where thoracic endograft implantations are performed. Information was collected from every procedure performed in 5 years. Between 2012 and 2016, 131 thoracic stent graft implantations were performed in Hungary (67.18% male, mean age 62.80 years). 25.19% of the procedures were acute. 13.74% of the patients were diabetic. Indications for the procedure were aneurysm (64.89%), dissection (17.56%), aortic trauma (6.87%) and other conditions (10.69%). 73.91% of the dissection cases were acute. 16.47% of repaired aneurysms were ruptured. Additional preoperative revascularization (debranching) was performed in 26.72% of the cases. Postoperative stroke occured in 4.58%, temporary hemodialysis was needed in 1.53%, bowel ischaemia was present in 2.29% and reoperation within 30 days was needed in 5.34% of all cases. Thirty-day mortality of the procedure was 9.92%, 5-year long-term mortality reached 16.03%. Endovascular repair of the thoracic aorta is an effective procedure and our national data comfirmed its advantages compared to open thoracic surgery. Further use of the procedure in Hungary depends on the centralised care in vascular surgery and financial matters. Multidisciplinary cooperation and proper logistics are needed to provide patients with optimal treatment. Orv Hetil. 2018; 159(2): 53-57

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