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

Structured reporting platform improves CAD-RADS assessment.

BACKGROUND: Structured reporting in cardiac imaging is strongly encouraged to improve quality through consistency. The Coronary Artery Disease - Reporting and Data System (CAD-RADS) was recently introduced to facilitate interdisciplinary communication of coronary CT angiography (CTA) results. We aimed to assess the agreement between manual and automated CAD-RADS classification using a structured reporting platform. METHODS: Five readers prospectively interpreted 500 coronary CT angiographies using a structured reporting platform that automatically calculates the CAD-RADS score based on stenosis and plaque parameters manually entered by the reader. In addition, all readers manually assessed CAD-RADS blinded to the automatically derived results, which was used as the reference standard. We evaluated factors influencing reader performance including CAD-RADS training, clinical load, time of the day and level of expertise. RESULTS: Total agreement between manual and automated classification was 80.2%. Agreement in stenosis categories was 86.7%, whereas the agreement in modifiers was 95.8% for "N", 96.8% for "S", 95.6% for "V" and 99.4% for "G". Agreement for V improved after CAD-RADS training (p = 0.047). Time of the day and clinical load did not influence reader performance (p > 0.05 both). Less experienced readers had a higher total agreement as compared to more experienced readers (87.0% vs 78.0%, respectively; p = 0.011). CONCLUSIONS: Even though automated CAD-RADS classification uses data filled in by the readers, it outperforms manual classification by preventing human errors. Structured reporting platforms with automated calculation of the CAD-RADS score might improve data quality and support standardization of clinical decision making

Subclinical leaflet thrombosis is associated with impaired reverse remodelling after transcatheter aortic valve implantation

Cardiac CT is increasingly applied for planning and follow-up of transcatheter aortic valve implantation (TAVI). However, there are no data available on reverse remodelling after TAVI assessed by CT. Therefore, we aimed to evaluate the predictors and the prognostic value of left ventricular (LV) reverse remodelling following TAVI using CT angiography.We investigated 117 patients with severe, symptomatic aortic stenosis (AS) who underwent CT scanning before and after TAVI procedure with a mean follow-up time of 2.6 years after TAVI. We found a significant reduction in LV mass (LVM) and LVM indexed to body surface area comparing pre- vs. post-TAVI images: 180.5 ± 53.0 vs. 137.1 ± 44.8 g and 99.7 ± 25.4 vs. 75.4 ± 19.9 g/m2, respectively, both P < 0.001. Subclinical leaflet thrombosis (SLT) was detected in 25.6% (30/117) patients. More than 20% reduction in LVM was defined as reverse remodelling and was detected in 62.4% (73/117) of the patients. SLT, change in mean pressure gradient on echocardiography and prior myocardial infarction was independently associated with LV reverse remodelling after adjusting for age, gender, and traditional risk factors (hypertension, body mass index, diabetes mellitus, and hyperlipidaemia): OR = 0.27, P = 0.022 for SLT and OR = 0.22, P = 0.006 for prior myocardial infarction, OR = 1.51, P = 0.004 for 10 mmHg change in mean pressure gradient. Reverse remodelling was independently associated with favourable outcomes (HR = 0.23; P = 0.019).TAVI resulted in a significant LVM regression on CT. The presence of SLT showed an inverse association with LV reverse remodelling and thus it may hinder the beneficial LV structural changes. Reverse remodelling was associated with improved long-term prognosis

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