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 ... Show moreTo 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. Show less
Bijl, N. van der; Joemai, R.M.S.; Mertens, B.J.A.; Roos, A. de; Veldkamp, W.J.H.; Bax, J.J.; ... ; Kroft, L.J.M. 2013
Chapter 1 reviews technical developments of cardiac CT and current status, recommendations and future perspective of various clinical cardiac CT applications. In chapter 2, the eff ect of dose... Show moreChapter 1 reviews technical developments of cardiac CT and current status, recommendations and future perspective of various clinical cardiac CT applications. In chapter 2, the eff ect of dose reduction on diagnostic performance in CT coronary angiography is assessed. Chapter 3 evaluates the eff ect of thin-slice image reconstructions on coronary artery calcium measurements. In chapter 4, the assessment of Agatston scores using coronary CT angiography is studied. Chapter 5 evaluates the predictive value of CT-derived RV/LV ratios and cardiac biomarkers for short term clinical outcome in patients with suspected acute PE. In chapter 6, the incremental value of ventricular function with ECG-synchronized cardiac CT over standard pulmonary CTA-derived RV/LV ratios for predicting clinical outcome in patients with suspected acute PE is discussed. Chapter 7 studies the influence of timing of NT-pro-BNP sampling for predicting adverse clinical outcome. Show less
Bijl, N. van der; Klok, F.A.; Huisman, M.V.; Rooden, J.K. van; Mertens, B.J.A.; Roos, A. de; Kroft, L.J.M. 2011
OBJECTIVE. The purpose of this article is to evaluate to what extent Agatston scores may be derived from CT coronary angiography (CTA) examinations, compared with traditional unenhanced CT calcium... Show moreOBJECTIVE. The purpose of this article is to evaluate to what extent Agatston scores may be derived from CT coronary angiography (CTA) examinations, compared with traditional unenhanced CT calcium scores. MATERIALS AND METHODS. Fifty patients with a CT calcium score-Agatston score of zero and 50 patients with a CT calcium score-Agatston score of 1 or greater whose CT calcium scores had been calculated and who had undergone CTA using volumetric 320-MDCT were included. Agatston scores were obtained at 3.0-mm slices for CT calcium score and CTA. Method agreement, interobserver agreement, and diagnostic performance of CTA for detecting coronary calcium were evaluated. RESULTS. Of 50 patients with a positive CT calcium score-Agatston score, coronary artery calcium was detected with CTA in 43 patients by observer 1 (mean CTA score, 102 +/- 202; mean CT calcium score, 254 +/- 501) and in 46 patients by observer 2 (mean CTA score, 94 +/- 147; mean CT calcium score, 272 +/- 531). Of the 50 patients with a CT calcium score-Agatston score of zero, 49 (98%, observer 1) and 50 (100%, observer 2) had a zero score with CTA as well. An intraclass correlation of 0.78 and 0.62 was found between CT calcium score and CTA (p < 0.01), whereas higher Agatston scores were underestimated with CTA. For observer 1, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for detection of coronary calcium with CTA were 86%, 98%, 98%, 88%, and 92%, respectively, and the corresponding values for observer 2 were 92%, 100%, 100%, 93%, and 96%, respectively. Interobserver agreement was 0.996 for CT calcium score and 0.93 for CTA. CONCLUSION. Coronary artery calcium can be detected on CTA images with high accuracy. The Agatston calcium score derived from CTA images shows good correlation with unenhanced CT calcium score and is highly reproducible. However, higher Agatston scores are systematically underestimated when derived from CTA images. Show less
Bijl, N. van der; Bruin, P.W. de; Geleijns, J.; Bax, J.J.; Schuijf, J.D.; Roos, A. de; Kroft, L.J.M. 2010
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... Show moreThe 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 +/- A 495 vs. 231 +/- A 461. Mean volume score: 223 +/- A 399 vs. 206 +/- A 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. Show less
Klok, F.A.; Bijl, N. van der; Roos, A. de; Kroft, L.J.M.; Huisman, M.V. 2010
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... Show moreThe 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. Show less
