Image Quality and Radiation Dose Stratified by Patient Heart Rate for Coronary 64- and 320-MDCT Angiography

Kondo

Circ: Cardiovascular Imaging

et al. 2014

Self Cite

Computed Tomography (AUC2010) does not incorporate prior coronary computed tomographic angiography (CCTA) results in the appropriateness of a CCTA examination. The purpose of this study was to explore the criteria for forgoing repeat CCTA among patients with clinical scenarios suggesting CCTA as appropriate after prior CCTA excluding coronary artery disease. Methods and Results-Among patients from a single center (February 2006 to April 2013) who underwent appropriate CCTA based on AUC2010, consecutive 555 CCTAs, which had a prior CCTA excluding significant stenosis (>50% stenosis in diameter), were selected. The median time difference between the studies was 34.2 (Q1-Q3, 22.9-50.1) months. Significant stenosis was detected at the time of repeat scan (by CCTA or subsequent catheter angiography) in 13.3% (74 of 555). A multivariable logistic model (C-statistic, 0.74; bootstrapped overfitting bias, 0.8%) identified 3 predictors of significant stenosis: time difference between the studies >3 years (adjusted odds ratio, 2.1; 95% confidence interval, 1.2-3.5), diabetes mellitus (odds ratio, 2.4; 95% confidence interval,1.4-4.3), and 26% to 50% stenosis on the initial CCTA (odds ratio, 5.6; 95% confidence interval, 3.2-9.6). When these 3 factors were all absent (corresponding to 31.9% of the population), the probability of significant stenosis was 4.5% (95% confidence interval, 2.7-7.4%), whereas 17.1% of patients had significant stenosis among those with at least 1 positive variable. When coronary arteries were completely normal at the initial scan, the prevalence of significant stenosis was only 1.8% irrespective of other factors, and no patient underwent revascularization. Conclusions-Nondiabetic patients with a prior CCTA <3 years showing no or ≤25% stenosis had a <5% prevalence of significant stenosis.

Section: Discussionmentioning

confidence: 99%

Repeat Coronary Computed Tomographic Angiography in Patients With a Prior Scan Excluding Significant Stenosis

Kondo

Circ: Cardiovascular Imaging

et al. 2014

Self Cite

“…The maximum coverage of MDCT in the z-direction is 160 mm with a 320-or 256-detector row CT. The 320-detector row CT system is effective for various diagnostic imaging owing to a wide coverage with fixedtable scanning, particularly for cardiac CT [6,7]. The 320-detector row CT is also designed to enable helical scanning with detector configurations using 4-, 16-, 32-, 64-, 80-, 100-, and 160-detector rows for routine CT examinations.…”

Section: Introductionmentioning

confidence: 99%

Comparative evaluation of image quality among different detector configurations using area detector computed tomography

Miura

Ichikawa

Fujimura

et al. 2018

Radiol Phys Technol

The 320-detector row computed tomography (CT) system, i.e., the area detector CT (ADCT), can perform helical scanning with detector configurations of 4-, 16-, 32-, 64-, 80-, 100-, and 160-detector rows for routine CT examinations. This phantom study aimed to compare the quality of images obtained using helical scan mode with different detector configurations. The image quality was measured using modulation transfer function (MTF) and noise power spectrum (NPS). The system performance function (SP), based on the pre-whitening theorem, was calculated as MTF 2 /NPS, and compared between configurations. Five detector configurations, i.e., 0.5 9 16 mm (16 row), 0.5 9 64 mm (64 row), 0.5 9 80 mm (80 row), 0.5 9 100 mm (100 row), and 0.5 9 160 mm (160 row), were compared using a constant volume CT dose index (CTDI vol ) of 25 mGy, simulating the scan of an adult abdomen, and with a constant effective mAs value. The MTF was measured using the wire method, and the NPS was measured from images of a 20-cm diameter phantom with uniform content. The SP of 80-row configuration was the best, for the constant CTDI vol , followed by the 64-, 160-, 16-, and 100-row configurations. The decrease in the rate of the 100-and 160-row configurations from the 80-row configuration was approximately 30%. For the constant effective mAs, the SPs of the 100-row and 160-row configurations were significantly lower, compared with the other three detector configurations. The 80-and 64-row configurations were adequate in cases that required dose efficiency rather than scan speed.

“…2 A stable heart rate lower than 65 beats per minute (bpm) is recommended when a typical CT scanner is used during coronary CT angiography. 3,4 Oral or intravenous β-blockers are used in order to achieve an optimal heart rate during the scan. 5 Oral metoprolol or propranolol is typically given as a premedication as it is most effective at 1 hour after administration.…”

Section: Introductionmentioning

confidence: 99%

“…48 An optimal heart rate to obtain a diagnostic image quality using 64-row CT was reported as ,65 bpm. 2,3 Recently, scanners that cover the entire heart in one rotation have become available. Because wide area coverage does not directly increase the temporal resolution, the initial 320-row CT requires a heart rate lower than 65 bpm for optimal image quality.…”

mentioning

confidence: 99%

“…Because wide area coverage does not directly increase the temporal resolution, the initial 320-row CT requires a heart rate lower than 65 bpm for optimal image quality. 3 The latest 320-row CT increased the gantry rotation time up to 275 ms; thus, optimal image quality could be obtained up to 75 bpm. 51 Low heart rate is important for decreasing the radiation exposure, especially in high-end scanners.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Clinical utility of landiolol for use in coronary CT angiography

Tomizawa¹,

Hayakawa²,

Inoh³

et al. 2015

RRCC

Although remarkable advancement in computed tomography (CT) has been achieved, heart rate control is important to maintain an optimal image quality in coronary CT angiography. Oral or intravenous β-blockers are used as premedication for this purpose. Landiolol was developed as a β-blocker with very high cardioselectivity (β1/β2 =255) and short half-life (4 minutes). In this review, we report the pharmacological features and usage of landiolol and also its effects on heart rate and image quality in coronary CT angiography. In addition, we discuss the safety of landiolol.