A novel ultrafast-low-dose computed tomography protocol allows concomitant coronary artery evaluation and lung cancer screening

BACKGROUND:Cardiac computed tomography (CT) is often performed in patients who are at high risk for lung cancer in whom screening is currently recommended. We tested diagnostic ability and radiation exposure of a novel ultra-low-dose CT protocol that allows concomitant coronary artery evaluation and lung screening. METHODS: We studied 30 current or former heavy smoker subjects with suspected or known coronary artery disease who underwent CT assessment of both coronary arteries and thoracic area (Revolution CT, General Electric). A new ultrafast-low-dose single protocol was used for ECG-gated helical acquisition of the heart and the whole chest. A single IV iodine bolus (70-90 ml) was used. All patients with CT evidence of coronary stenosis underwent also invasive coronary angiography. RESULTS: All the coronary segments were assessable in 28/30 (93%) patients. Only 8 coronary segments were not assessable in 2 patients due to motion artefacts (assessability: 98%; 477/485 segments). In the assessable segments, 20/21 significant stenoses (> 70% reduction of vessel diameter) were correctly diagnosed. Pulmonary nodules were detected in 5 patients, thus requiring to schedule follow-up surveillance CT thorax. Effective dose was 1.3 ± 0.9 mSv (range: 0.8-3.2 mSv). Noteworthy, no contrast or radiation dose increment was required with the new protocol as compared to conventional coronary CT protocol. CONCLUSIONS:The novel ultrafast-low-dose CT protocol allows lung cancer screening at time of coronary artery evaluation. The new approach might enhance the cost-effectiveness of coronary CT in heavy smokers with suspected or known coronary artery disease

Multi-scale analysis of lung computed tomography images

A computer-aided detection (CAD) system for the identification of lung internal nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 project. The three modules of our lung CAD system, a segmentation algorithm for lung internal region identification, a multi-scale dot-enhancement filter for nodule candidate selection and a multi-scale neural technique for false positive finding reduction, are described. The results obtained on a dataset of low-dose and thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.Comment: 18 pages, 12 low-resolution figure

Lung nodule detection on thoracic computed tomography images: Preliminary evaluation of a computerâ aided diagnosis system

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135039/1/mp5762.pd

Focal Spot, Spring 2000

https://digitalcommons.wustl.edu/focal_spot_archives/1084/thumbnail.jp

Reduction of radiation dose for coronary computed tomography angiography using prospective electrocardiography-triggered high-pitch acquisition in clinical routine

Purpose: To evaluate the image quality, radiation exposure, and means of application in a group of patients who underwent coronary computed tomography angiography (CCTA) performed with low-dose prospective electrocardiography (ECG)-triggered acquisition in which a standard sequence was added if the low-dose sequence did not allow reliable exclusion of coronary stenosis with respect to image quality. Material and methods: The present study was approved by the Ethics Committee of the Faculty of Medicine, and informed consent was obtained from all patients. The authors performed a retrospective review of 256 consecutive patients referred for CCTA using dual-source CT scanner (Definition FLASH, Siemens, Germany). CCTA was performed using prospective ECG-triggered high-pitch acquisition. In patients with higher heart rates (> 65 bpm) or in whom irregular heart rates were noted prior to the scan, a subsequent CCTA was performed immediately (double flash protocol). The effective radiation dose was calculated for each patient. All images were evaluated by two independent observers for quality on a four-point scale with 1 being non-diagnostic image quality and 4 being excellent. Results: Mean effective whole-body dose of CCTA was 1.6 ± 0.4 mSv (range, 0.4-5.4) for the entire cardiac examination and 0.9 ± 0.3 mSv (range, 0.4-2.8) for individual prospective ECG-triggered high-pitch CCTAs. In 27 of these patients with higher heart rates or occasional premature ventricular contractions or atrial fibrillation, subsequent CCTAs were performed immediately. The average image quality score was good to excellent with less than 1% unevaluable coronary segments. The double flash protocol resulted in a fully diagnostic CCTA in all cases. Conclusions: The prospective ECG-triggered high-pitch CCTA technique is feasible and promising in clinical routine with good to excellent image quality and minimal radiation dose. The double flash protocol might become a more robust tool in patients with higher heart rates or arrhythmia

Computerâ aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135040/1/mp7129.pd

AN EVALUATION OF THE INCREMENTAL VALUE OF COMPUTED TOMOGRAPHIC BIOMARKERS IN CARDIOVASCULAR RISK PREDICTION

Predicting cardiovascular events is an important subject in the developed world as it is a major cause of morbidity and mortality. Identifying those at risk of developing cardiovascular disease is key as there are treatments available to reduce the risk of future events. The most well-known prediction tool is the Framingham Risk Score (FRS), a multivariate cardiovascular risk prediction model. The Framingham cohort identified some of the most fundamental risk factors that shape modern cardiovascular prevention, however, it is not a perfect model. The imperfect nature of cardiovascular risk prediction based on FRS forms the starting point of this research journey. In the search for a better prediction tool, a logical approach would be to improve on an existing model, rather than ‘reinventing the wheel’. This philosophy underpins this piece of work, which focuses on finding a tool that improves identification of subclinical disease. From my clinical practice in radiology, the value of cardiovascular CT biomarkers became an obvious area to investigate. Over the course of my research, I realised both cardiovascular (CVD) risk prediction models and CVD CT biomarkers have evolved over a similar period. The scope of my research demanded my attention to focus on FRS as a base model, though there are many other CVD risk prediction models. Similarly, there are multiple cardiovascular CT biomarkers that have been proposed. The best studied CT biomarker in terms of predicting CVD events is undoubtedly coronary calcium score (CACS). Considering the evolving nature of CT technology and the deeper understanding of CVD pathophysiology, there are two other up-and-coming biomarkers, namely thoracic calcium score (TACS) and coronary artery stenosis, which broaden the scope of investigating potentially useful biomarkers. Embedding CT biomarkers within Framingham Risk Score formed the framework investigation. Derived from this was a journey of discovery that led me to learn the rapidly expanding knowledge of prognosis research. My initial investigation was conducting a systematic review and meta-analysis of the incremental value of discussed CT biomarkers. This was followed by investigating the reporting standard of the Framingham Model within the realm of incremental value added by CT biomarkers. Finally, performing a feasibility study to look at whether the coronary arteries can be assessed during routine oncological whole-body CT imaging. I would like to illustrate and share my learning in the subsequent chapters.University Hospitals Plymouth NHS TrustNational Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) South West Peninsul

Novel approaches to the assessment of patients with chest systoms in the acute medical and outpatient settings: the use of multislice computed tomography

This thesis evaluated the clinical utility of cardiopulmonary computed tomography (CT) in patients presenting with chest pain and dyspnoea. Studies within this thesis confirmed the following. Firstly, there is a requirement for improved diagnostic pathways to minimise patients being discharged without a diagnosis, which currently occurs in 30-40% of patients admitted with chest pain and dyspnoea. Historically, CT has been utilised in 32% of admissions with chest pain and 10% of admissions with dyspnoea. Secondly, challenges exist to the wider adoption of cardiopulmonary CT. These include patient-related factors, institutional capabilities and guideline restrictions. In acute admissions, 11% of patients with dyspnoea and 7% of patients with chest pain and a low to moderate likelihood of CAD are suitable for CT. In the RACPC setting, including patients across the entire spectrum of CAD likelihood, 18% of patients are suitable for CT. NICE CG95 would recommend only 1% of acute chest pain admissions and 2% of RACPC attenders for CT. Thirdly, NICE CG95 would recommend 51% of acute chest pain admissions and 66% of RACPC attenders for discharge without cardiac investigation. In the RACPC population, significant CAD is identified in 10% of these patients and a major adverse cardiac event in 2%. Fourthly, in selected patients with suspected cardiac chest pain, cardiac CT has a diagnostic yield of 21% in acute admissions and 13% in RACPC attenders for significant CAD. In acute admissions with dyspnoea, cardiopulmonary CT has a diagnostic yield of 20% for CAD, 20% for pulmonary embolism, nil for aortic dissection and 89% for non-vascular chest pathology. Fifthly, inclusion of CT in diagnostic pathways for chest pain result in fewer patients discharged without a diagnosis, fewer invasive angiography procedures and reduced diagnostic costs. In patients with dyspnoea, CT provides value to clinicians making diagnoses and supports early discharge without detrimental outcomes.Open Acces