Technology of cardiac computed tomography

ESC CardioMed ◽  
2018 ◽  
pp. 537-541
Author(s):  
Stephan Achenbach
Keyword(s):  
Computed Tomography ◽  
Heart Rate ◽  
Coronary Arteries ◽  
Cardiac Computed Tomography ◽  
Ct Imaging ◽  
Breath Hold ◽  
Coronary Angiogram ◽  
Data Set ◽  
Careful Patient ◽  
Patient Preparation

Cardiac imaging by computed tomography (CT) has the unique advantage of providing a fully isotropic data set with high spatial resolution. However, the rapid motion of the heart poses substantial challenges to CT imaging. For this reason, specific techniques have been developed to increase the temporal resolution of CT imaging and to permit either image acquisition or data reconstruction in synchronization with the patient’s electrocardiogram. Next to the use of advanced scanner technology, careful patient preparation is important to avoid artefacts. This includes careful coaching and practising of the breath-hold sequence to lower the heart rate, especially when CT is used to visualize the coronary arteries. With modern scanners, radiation exposure is reasonably low and falls approximately in the range of an invasive coronary angiogram.

scholarly journals Bailout intravenous esmolol for heart rate control in cardiac computed tomography angiography

2016 ◽  
Vol 35 (12) ◽  
pp. 673-678 ◽  
Author(s):  
Sílvia Aguiar Rosa ◽  
Ruben Ramos ◽  
Hugo Marques ◽  
Rosana Santos ◽  
Cecília Leal ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Heart Rate ◽  
Computed Tomography Angiography ◽  
Rate Control ◽  
Cardiac Computed Tomography ◽  
Heart Rate Control ◽  
Cardiac Computed Tomography Angiography

scholarly journals Transition from Transesophageal Echocardiography to Cardiac Computed Tomography for the Evaluation of Left Atrial Appendage Thrombus Prior to Atrial Fibrillation Ablation and Incidence of Cerebrovascular Events During the COVID-19 Pandemic

2021 ◽  
Author(s):  
Tauseef Akhtar ◽  
Ryan Wallace ◽  
Usama Daimee ◽  
Erica Hart ◽  
Armin Arbab-Zadeh ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Atrial Fibrillation ◽  
Transesophageal Echocardiography ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Cardiac Computed Tomography ◽  
Ct Imaging ◽  
Atrial Appendage ◽  
Af Ablation ◽  
Cerebrovascular Events

Background Transesophageal echocardiography (TEE) is variably performed before atrial fibrillation (AF) ablation to evaluate left atrial appendage (LAA) thrombus. We describe our experience with transitioning to the pre-ablation cardiac computed tomography (CT) approach for the assessment of LAA thrombus during the COVID-19 pandemic. Methods We studied consecutive patients undergoing AF ablation at our center. The study cohort was divided into pre- vs. post-COVID groups. The pre-COVID cohort included ablations performed during 1 year before the COVID-19 pandemic; pre-ablation TEE was used routinely to evaluate LAA thrombus in high-risk patients. Post-COVID cohort included ablations performed during the 1 year after the COVID-19 pandemic; pre-ablation CT was performed in all patients, with TEE performed only in patients with LAA thrombus by CT imaging. The demographics, clinical history, imaging, and ablation characteristics, and peri-procedural cerebrovascular events (CVE) were recorded. Results A total of 637 patients (pre-COVID n=424, post-COVID n=213) were studied. The mean age was 65.6  10.1 years in the total cohort, and the majority were men. There was a significant increase in pre-ablation CT imaging from pre to post-COVID cohort (74.8 vs. 93.9%, p=<0.01), with a significant reduction in TEEs (34.6 vs. 3.7%, p=<0.01). One patient in the post-COVID cohort developed CVE following negative pre-ablation CT. However, the incidence of peri-procedural CVE between both cohorts remained statistically unchanged (0 vs. 0.4%, p=0.33). Conclusion Implementation of pre ablation CT-only imaging strategy with selective use of TEE for LAA thrombus evaluation is not associated with increased CVE risk during the COVID- 19 pandemic.

Functional anatomy of myocardial perfusion

ESC CardioMed ◽  
2018 ◽  
pp. 106-110
Author(s):  
Robert Manka ◽  
Sabrina Oebel
Keyword(s):  
Computed Tomography ◽  
Myocardial Perfusion ◽  
Coronary Arteries ◽  
Single Photon ◽  
Cardiac Computed Tomography ◽  
Photon Emission ◽  
Functional Anatomy ◽  
Imaging Modalities ◽  
Perfusion Studies ◽  
Artery Disease

The continuous development of cardiac imaging modalities in recent years has led to a better understanding of myocardial perfusion on a structural level by allowing detection of myocardial blood flow alterations caused by obstructed coronary arteries or different cardiac pathologies. Apart from direct visualization of the epicardial coronary arteries by coronary angiography or cardiac computed tomography, the diagnosis of functionally relevant stenosis often requires additional techniques such as invasive fractional flow reserve measurements. The possibility of a non-invasive assessment of coronary perfusion status including pathologies which may otherwise evade detection by standard angiography, such as microvascular disease, by imaging modalities such as single-photon emission computed tomography and cardiovascular magnetic resonance imaging has significantly changed clinical management of patients with suspected or known coronary artery disease. Using an integrated diagnostic approach combining functional information gained by perfusion studies and structural data covering coronary anatomy, the planning of interventional procedures and further risk stratification may be significantly improved.

Virtual monochromatic imaging reduces beam hardening artefacts in cardiac interior photon counting computed tomography: a phantom study with cadaveric specimens

2021 ◽  
Author(s):  
Satu Irene Inkinen ◽  
Mikael Asko Kaarlo Juntunen ◽  
Juuso Heikki Jalmari Ketola ◽  
Kristiina Korhonen ◽  
Pasi Sepponen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Coronary Artery ◽  
Ex Vivo ◽  
Cardiac Computed Tomography ◽  
Photon Counting ◽  
High Energy ◽  
Ct Imaging ◽  
Material Decomposition ◽  
Beam Hardening ◽  
Selection Of

Abstract In interior cardiac computed tomography (CT) imaging, the x-ray beam is collimated to a limited field-of-view covering the heart volume, which decreases the radiation exposure to surrounding tissues. Spectral CT enables the creation of virtual monochromatic images (VMIs) through a computational material decomposition process. This study investigates the utility of VMIs for beam hardening (BH) reduction in interior cardiac CT, and further, the suitability of VMIs for coronary artery calcium (CAC) scoring and volume assessment is studied using spectral photon counting detector CT (PCD-CT). Ex vivo coronary artery samples (N=18) were inserted in an epoxy rod phantom. The rod was scanned in the conventional CT geometry, and subsequently, the rod was positioned in a torso phantom and re-measured in the interior PCD-CT geometry. The total energy (TE) 10-100 keV reconstructions from PCD-CT were used as a reference. The low energy 10-60 keV and high energy 60-100 keV data were used to perform projection domain material decomposition to polymethyl methacrylate and calcium hydroxylapatite basis. The truncated basis-material sinograms were extended using the adaptive detruncation method. VMIs from 30-180 keV range were computed from the detruncated virtual monochromatic sinograms using filtered back projection. Detrending was applied as a post-processing method prior to CAC scoring. The results showed that BH artefacts from the exterior structures can be suppressed with high (≥100 keV) VMIs. With appropriate selection of the monoenergy (46 keV), the underestimation trend of CAC scores and volumes shown in Bland-Altman (BA) plots for TE interior PCD-CT was mitigated, as the BA slope values were -0.02 for the 46 keV VMI compared to -0.21 the conventional TE image. To conclude, spectral PCD-CT imaging using VMIs could be applied to reduce BH artefacts interior CT geometry, and further, optimal selection of VMI may improve the accuracy of CAC scoring assessment in interior PCD-CT.

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