Assessment of coronary artery calcium by using volumetric 320-row multi-detector computed tomography: comparison of 0.5 mm with 3.0 mm slice reconstructions

The purpose of this study was to assess the performance of 0.5 versus 3.0 mm slice reconstructions in depicting coronary calcium with special attention to patients having zero calcium scores at 3.0 mm reconstructions by using computed tomography (CT). Imaging was performed by volumetric 320-detector row CT. Scans of 100 patients with a negative and 100 patients with a positive Agatston score at 3.0 mm reconstructions were consecutively selected. Non-overlapping volume sets with 3.0 and 0.5 mm slice thickness were reconstructed from the same raw data and Agatston and volume scores were obtained. The Wilcoxon signed ranks test was used to determine statistical differences between 3.0 and 0.5 mm calcium scores. Agatston and volume scores obtained at 0.5 mm were significantly higher than at 3.0 mm reconstructions (mean Agatston score: 266 ± 495 vs. 231 ± 461. Mean volume score: 223 ± 399 vs. 206 ± 385, both P < 0.01). In 21% of patients with zero 3.0 mm Agatston scores, a positive Agatston and/or volume score was found at 0.5 mm reconstructions. With volumetric 320-detector row CT, prospective ECG-triggered calcium scoring at 0.5 mm compared to 3.0 mm reconstructions leads to an increase in Agatston and volume scores and small amounts of coronary calcium are earlier depicted. This may be of special interest in patients with zero calcium scores with traditional 3.0 mm measures, where 0.5 mm reconstructions may help in superior depicting or ruling out coronary artery disease

Diagnostic performance of 320-slice multidetector computed tomography coronary angiography in patients after coronary artery bypass grafting

Cardiovascular Aspects of Radiolog

Effect of dose reduction on image quality and diagnostic performance in coronary computed tomography angiography

To evaluate the effect of radiation dose reduction on image quality and diagnostic accuracy of coronary computed tomography (CT) angiography. Coronary CT angiography studies of 40 patients with (n = 20) and without (n = 20) significant (≥50 %) stenosis were included (26 male, 14 female, 57 ± 11 years). In addition to the original clinical reconstruction (100 % dose), simulated images were created that correspond to 50, 25 and 12.5 % of the original dose. Image quality and diagnostic performance in identifying significant stenosis were determined. Receiver–operator-characteristics analysis was used to assess diagnostic accuracy at different dose levels. The identification of patients with significant stenosis decreased consistently at doses of 50, 25 and 12.5 of the regular clinical acquisition (100 %). The effect was relatively weak at 50 % dose, and was strong at dose levels of 25 and 12.5 %. At lower doses a steady increase was observed for false negative findings. The number of coronary artery segments that were rated as diagnostic decreased gradually with dose, this was most prominent for smaller segments. The area-under-the-curve (AUC) was 0.90 (p = 0.4) at 50 % dose; accuracy decreased significantly with 25 % (AUC 0.70) and 12.5 % dose (AUC 0.60) (p < 0.0001), with underestimation of patients having significant stenosis. The clinical acquisition protocol for evaluation of coronary artery stenosis with CT angiography represents a good balance between image quality and patient dose. A potential for a modest (<50 %) reduction of tube current might exist. However, more substantial reduction of tube current will reduce diagnostic performance of coronary CT angiography substantially

Breast Implant Prevalence in the Dutch Female Population Assessed by Chest Radiographs

BACKGROUND: Breast implant-related health problems are a subject of fierce debate. Reliable population-based estimates of implant prevalence rates are not available, however, due to a lack of historical registries and incomplete sales data, precluding absolute risk assessments. OBJECTIVES: This study aimed to describe the methodology of a novel procedure to determine Dutch breast implant prevalence based on the evaluation of routine chest radiographs. METHODS: The validity of the new method was first examined in a separate study. Eight reviewers examined a series of 180 chest radiographs with (n = 60) or without (n = 120) a breast implant confirmed by a computed tomography or magnetic resonance imaging scan. After a consensus meeting with best-performing expert reviewers, we reviewed 3000 chest radiographs of women aged 20 to 70 years in 2 large regional hospitals in the Netherlands in 2015. To calculate the national breast implant prevalence, regional prevalence variations were corrected utilizing the National Breast Cancer Screening Program. RESULTS: Eight reviewers scored with a median sensitivity of 71.7% (range, 41.7%-85.0%) and a median specificity of 94.6% (range, 73.4%-97.5%). After a consensus meeting and a reevaluation by best-performing expert reviewers, sensitivity was 79.9% and specificity was 99.2%. The estimated national prevalence of breast implants among women between 20 and 70 years was 3.0%, ranging from 1.7% at 21 to 30 years to 3.9% between 51 and 60 years. CONCLUSIONS: The novel method in this study was validated with a high sensitivity and specificity, resulting in accurate prevalence estimates and providing the opportunity to conduct absolute risk assessment studies on the health consequences of breast implants