Multi-atlas-based segmentation with local decision fusion--application to cardiac and aortic segmentation in CT scans.

A novel atlas-based segmentation approach based on the combination of multiple registrations is presented. Multiple atlases are registered to a target image. To obtain a segmentation of the target, labels of the atlas images are propagated to it.

Automatic segmentation of the pulmonary lobes from fissures, airways, and lung borders: evaluation of robustness against missing data.

Automatic segmentation of structures with missing or invisible borders is a challenging task. Since structures in the lungs are related, humans use contextual and shape information to infer the position of invisible borders. An example of a task in which the borders are often incomplete or invisible is the segmentation of the pulmonary lobes.

Image subtraction facilitates assessment of volume and density change in ground-glass opacities in chest CT.

Objectives: To study the impact of image subtraction of registered images on the detection of change in pulmonary ground-glass nodules identified on chest CT.

Materials And Methods: A cohort of 33 individuals (25 men, 8 women; age range 51-75 years) with 37 focal ground-glass opacities (GGO) were recruited from a lung cancer screening trial. For every participant, 1 to 3 follow-up scans were available (total number of pairs, 84).

Diagnostic accuracy of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study.

Objectives: This study sought to determine the diagnostic accuracy of 64-slice computed tomographic coronary angiography (CTCA) to detect or rule out significant coronary artery disease (CAD).

Background: CTCA is emerging as a noninvasive technique to detect coronary atherosclerosis.

Methods: We conducted a prospective, multicenter, multivendor study involving 360 symptomatic patients with acute and stable anginal syndromes who were between 50 and 70 years of age and were referred for diagnostic conventional coronary angiography (CCA) from September 2004 through June 2006.

A comparison of six software packages for evaluation of solid lung nodules using semi-automated volumetry: what is the minimum increase in size to detect growth in repeated CT examinations.

We compared interexamination variability of CT lung nodule volumetry with six currently available semi-automated software packages to determine the minimum change needed to detect the growth of solid lung nodules. We had ethics committee approval. To simulate a follow-up examination with zero growth, we performed two low-dose unenhanced CT scans in 20 patients referred for pulmonary metastases.

Smooth or attached solid indeterminate nodules detected at baseline CT screening in the NELSON study: cancer risk during 1 year of follow-up.

Purpose: To retrospectively determine whether baseline nodule characteristics at 3-month and 1-year volume doubling time (VDT) are predictive for lung cancer in solid indeterminate noncalcified nodules (NCNs) detected at baseline computed tomographic (CT) screening.

Materials And Methods: The study, conducted between April 2004 and May 2006, was institutional review board approved. Patient consent was waived for this retrospective evaluation.

Dynamic aortic changes in patients with thoracic aortic aneurysms evaluated with electrocardiography-triggered computed tomographic angiography before and after thoracic endovascular aneurysm repair: preliminary results.

The purpose of this study was to utilize dynamic computed tomographic angiography (CTA) on pre- and postoperative thoracic endovascular aneurysm repair (TEVAR) patients to characterize cardiac pulsatility-induced aortic motion on essential TEVAR proximal sealing zones and to study the influence of endograft placement. Six pre- and six postoperative dynamic CTA studies were obtained in six patients with thoracic aortic aneurysms (TAAs) undergoing TEVAR. Data were acquired using a retrospective electrocardiography-triggered dynamic CTA scan, with eight reconstructed phases over the cardiac cycle.

CTPA for the diagnosis of acute pulmonary embolism during pregnancy.

CT pulmonary angiography (CTPA) has been suggested by the Fleischner society as the first test following a negative leg ultrasound in pregnant patients with suspected pulmonary embolism. This editorial discusses the use of CTPA as a diagnostic tool in pregnant women and comments on the need for specifically adapting CT protocols during pregnancy in the light of new research describing a substantial number of non-diagnostic examinations in pregnant women if routine scanning protocols are used for CTA of the pulmonary arteries. Potential reasons for these high numbers of insufficient examinations are physiological changes occurring during pregnancy that lead to a hyperdynamic circulation, which reduces average enhancement of the pulmonary vasculature.

Relation of epicardial and pericoronary fat to coronary atherosclerosis and coronary artery calcium in patients undergoing coronary angiography.

Fat surrounding coronary arteries might aggravate coronary artery disease (CAD). We investigated the relation between epicardial adipose tissue (EAT) and pericoronary fat and coronary atherosclerosis and coronary artery calcium (CAC) in patients with suspected CAD and whether this relation is modified by total body weight. This was a cross-sectional study of 128 patients with angina pectoris (61 +/- 6 years of age) undergoing coronary angiography.

Non-invasive cardiac assessment in high risk patients (The GROUND study): rationale, objectives and design of a multi-center randomized controlled clinical trial.

Background: Peripheral arterial disease (PAD) is a common disease associated with a considerably increased risk of future cardiovascular events and most of these patients will die from coronary artery disease (CAD). Screening for silent CAD has become an option with recent non-invasive developments in CT (computed tomography)-angiography and MR (magnetic resonance) stress testing. Screening in combination with more aggressive treatment may improve prognosis.

Fast noise reduction in computed tomography for improved 3-D visualization.

Computed tomography (CT) has a trend towards higher resolution and higher noise. This development has increased the interest in anisotropic smoothing techniques for CT, which aim to reduce noise while preserving structures of interest. However, existing smoothing techniques are slow, which makes clinical application difficult.

Effect of nodule characteristics on variability of semiautomated volume measurements in pulmonary nodules detected in a lung cancer screening program.

Purpose: To retrospectively assess volume measurement variability in solid pulmonary nodules (volume, 15-500 mm(3)) detected at lung cancer screening and to quantify the independent effects of nodule morphology, size, and location.

Materials And Methods: This retrospective study was a substudy of the screening program that was approved by the Dutch Ministry of Health, and all participants provided written informed consent. Two independent readers used semiautomated software to measure the volume of pulmonary nodules detected in 6774 participants aged 50-75 years (5917 men).

New challenges in MDCT.

The performance of computed tomography has approximately doubled every two years since the mid 1980s. The introduction of multidetector CT (MDCT) has sustained this trend. While 4-slice scanners were able to scan faster or with higher resolution than single slice units, 16-slice scanners introduced fast isotropic imaging and 32-to 64-slice scanners made it possible to combine ECG-gated cardiac evaluation with other CT applications.

Impact of computed tomography screening for lung cancer on participants in a randomized controlled trial (NELSON trial).

Background: Computed tomography (CT) screening is an important new tool for the early detection of lung cancer. In the current study, the authors assessed the discomfort associated with CT scanning and the subsequent wait for results and health-related quality of life (HRQoL) over time.

Methods: A total of 351 participants in the Dutch-Belgian randomized controlled trial for lung cancer screening in high-risk subjects (the NELSON trial) who had an appointment for a baseline CT scan were asked to complete questionnaires regarding their experienced discomfort and HRQoL before, 1 day after, and approximately 6 months after the CT scan.

Digital chest radiography: an update on modern technology, dose containment and control of image quality.

The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions.

Role of baseline nodule density and changes in density and nodule features in the discrimination between benign and malignant solid indeterminate pulmonary nodules.

Purpose: To retrospectively evaluate whether baseline nodule density or changes in density or nodule features could be used to discriminate between benign and malignant solid indeterminate nodules.

Materials And Methods: Solid indeterminate nodules between 50 and 500 mm(3) (4.6-9.

Visualizing type IV endoleak using magnetic resonance imaging with a blood pool contrast agent.

Growing evidence suggests that graft porosity hampers aneurysm shrinkage in patients who have been treated with the original Excluder device. To our knowledge, this suspected porosity has never been visualized in such patients. We present three patients treated with the original Excluder device whose aneurysms did not shrink in the first 2 years after treatment.

Variability of coronary calcium scores throughout the cardiac cycle: implications for the appropriate use of electrocardiogram-dose modulation with retrospectively gated computed tomography.

Objective: To study how much the calcium scores at various phases throughout the cardiac cycle deviate from the score in the most motionless phase during retrospectively electrocardiogram (ECG)-gated multidetector row computed tomography (MDCT) of the heart and to evaluate how to optimize ECG-based tube current modulation so that errors in calcium scoring can be minimized while dose savings can be maximized.

Materials And Methods: In 73 subjects with known or suspected coronary artery disease we performed retrospectively ECG-gated 64-detector row computed tomography for calcium scoring. Four subjects were excluded after scanning because of breathing artifacts or lack of coronary calcification.

Comparison of axial, coronal, and primary 3D review in MDCT colonography for the detection of small polyps: a phantom study.

Purpose: The purpose of this phantom study is to compare the influence of the reading technique (axial images alone in comparison to 3D endoluminal, coronal, and combined 2D/3D review methods) on the sensitivity and inter-reader variability with MDCT colonography for the detection of small colonic polyps.

Methods: An anthropomorphic pig colon phantom with 75 randomly distributed simulated small polyps of 2-8mm size, was distended with air and scanned in a water phantom using multidetector-row CT with 4mm x 1mm collimation. Three radiologists rated the presence of polyps on a five-point scale.

Computer-aided detection of interstitial abnormalities in chest radiographs using a reference standard based on computed tomography.

A computer-aided detection (CAD) system is presented for the localization of interstitial lesions in chest radiographs. The system analyzes the complete lung fields using a two-class supervised pattern classification approach to distinguish between normal texture and texture affected by interstitial lung disease. Analysis is done pixel-wise and produces a probability map for an image where each pixel in the lung fields is assigned a probability of being abnormal.

Peri-coronary epicardial adipose tissue is related to cardiovascular risk factors and coronary artery calcification in post-menopausal women.

Aims: To determine whether peri-coronary epicardial adipose tissue (EAT) is associated with vascular risk factors and coronary atherosclerosis.

Methods And Results: In this study, 573 healthy post-menopausal women underwent a cardiac CT scan to assess coronary calcification. Peri-coronary EAT thickness was measured in the areas of right coronary artery (RCA), left anterior descending (LAD) artery, and left circumflex (LCX) coronary artery.

Coronary calcification: effect of small variation of scan starting position on Agatston, volume, and mass scores.

Purpose: To retrospectively evaluate the effect of a small variation of scan starting position on coronary artery calcium scores based on nonoverlapping 3-mm multidetector computed tomographic (CT) data sets.

Materials And Methods: Informed consent and institutional review board approval were obtained. A retrospective study was performed by using prospective unenhanced electrocardiographically triggered cardiac multidetector CT scans in 228 women (mean age, 67 years +/- 5 [standard deviation]).

Pulmonary nodules: Interscan variability of semiautomated volume measurements with multisection CT-- influence of inspiration level, nodule size, and segmentation performance.

Purpose: To prospectively assess the precision of semiautomated volume measurements of pulmonary nodules at low-dose multi-detector row computed tomography (CT) and to investigate the influence of nodule size, segmentation algorithm, and inspiration level.

Materials And Methods: This study had institutional review board approval; written informed consent was obtained from all patients. Between June 2004 and March 2005, 20 patients (15 men, five women; age range, 40-84 years; mean age, 57 years) referred for chest CT for known lung metastases underwent two additional low-dose chest CT examinations without contrast material (collimation, 16 x 0.

Limited value of shape, margin and CT density in the discrimination between benign and malignant screen detected solid pulmonary nodules of the NELSON trial.

Purpose: To evaluate prospectively the value of size, shape, margin and density in discriminating between benign and malignant CT screen detected solid non-calcified pulmonary nodules.

Material And Methods: This study was institutional review board approved. For this study 405 participants of the NELSON lung cancer screening trial with 469 indeterminate or potentially malignant solid pulmonary nodules (>50mm3) were selected.