Coronary computed tomography angiography with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination

Aims To evaluate the feasibility and image quality of coronary computed tomography angiography (CCTA) acquisition with a submillisievert fraction of effective radiation dose using model-based iterative reconstruction (MBIR) for noise reduction. Methods and results In 42 patients undergoing standard low-dose (100-120 kV; 450-700 mA) and additional ultra-low-dose CCTA (80-100 kV; 150-210 mA) reconstructed with MBIR, segmental image quality was graded on a four-point scale [(i): non-evaluative, (ii): good, (iii): adequate, and (iv): excellent]. Signal-to-noise ratio (SNR) was calculated dividing left main artery (LMA) and right coronary artery (RCA) attenuation by the aortic root noise. Over a wide range of body mass index (18-40 kg/m2), the estimated median radiation dose exposure was 1.19 mSv [interquartile range (IQR): 1.07-1.30 mSv] for standard and 0.21 mSv (IQR: 0.18-0.23 mSv) for ultra-low-dose CCTA (P < 0.001). The median image quality score per segment was 3.5 (IQR: 3.0-4.0) in standard CCTA vs. 3.5 (IQR: 2.5-4.0) in ultra-low dose with MBIR (P = 0.29). Diagnostic image quality (scores 2-4) was found in 98.7 vs. 97.8% coronary segments (P = 0.36). Introduction of MBIR for ultra-low-dose CCTA resulted in a significant increase in SNR (P < 0.001) for LMA (from 15 ± 5 to 29 ± 7) and RCA (from 14 ± 4 to 27 ± 6) despite 82% dose reduction. Conclusion Coronary computed tomography angiography acquisition with diagnostic image quality is feasible at an ultra-lowradiation dose of 0.21 mSv, e.g. in the range reported for a postero-anterior and lateral chest X-ra

Coronary artery calcium quantification from contrast enhanced CT using gemstone spectral imaging and material decomposition

To explore the feasibility of coronary artery calcium (CAC) measurement from low-dose contrast enhanced coronary CT angiography (CCTA) as this may obviate the need for an unenhanced CT scan. 52 patients underwent unenhanced cardiac CT and prospectively ECG triggered contrast enhanced CCTA (Discovery HD 750, GE Healthcare, Milwaukee, WI, USA). The latter was acquired in single-source dual-energy mode [gemstone spectral imaging (GSI)]. Virtual unenhanced images were generated from GSI CCTA by monochromatic image reconstruction of 70 keV allowing selective iodine material suppression. CAC scores from virtual unenhanced CT were compared to standard unenhanced CT including a linear regression model. After iodine subtraction from the contrast enhanced CCTA the attenuation in the ascending aorta decreased significantly from 359 ± 61 to 54 ± 8 HU (P < 0.001), the latter comparing well to the value of 64 ± 55 HU found in the standard unenhanced CT (P = ns) confirming successful iodine subtraction. After introducing linear regression formula the mean values for Agatston, Volume and Mass scores of virtual unenhanced CT were 187 ± 321, 72 ± 114 mm(3), and 27 ± 46 mg/cm(3), comparing well to the values from standard unenhanced CT (187 ± 309, 72 ± 110 mm(3), and 27 ± 45 mg/cm(3)) yielding an excellent correlation (r = 0.96, r = 0.96, r = 0.92; P < 0.001). Mean estimated radiation dose revealed 0.83 ± 0.02 mSv from the unenhanced CT and 1.70 ± 0.53 mSv from the contrast enhanced CCTA. Single-source dual-energy scanning with GSI allows CAC quantification from low dose contrast enhanced CCTA by virtual iodine contrast subtraction

Prognostic value of coronary CT angiography on long-term follow-up of 6.9 years

Long term follow-up of coronary CT angiography (CCTA) is scarce. The aim of the present study was to assess the prognostic value of CCTA over a follow-up period of more than 6 years. 218 Patients were included undergoing 64-slice CCTA. Images were analysed with regard to the presence of nonobstructive (<50 %) or obstructive (50 % stenosis) coronary artery disease (CAD). Major adverse cardiovascular events (MACE) were defined as death, nonfatal myocardial infarction or urgent coronary revascularization. CCTA revealed normal coronaries in 49, nonobstructive lesions in 94, and obstructive CAD in 75 patients. During a median follow-up period of 6.9 years, MACE occurred in 45 patients (21 %). Annual MACE rates were 0.3, 2.7, and 6.0 % (p = 0.001), for patients with normal CCTA, nonobstructive, and obstructive CAD, respectively. Multivariate Cox regression analysis identified the number of segments with plaques [hazard ratio (HR) 1.18, p = 0.002] as well as the presence of obstructive lesions (HR 2.28, p = 0.036) as independent predictors of MACE. The present study extends the predictive value of CCTA over more than 6 years. Patients with normal coronary arteries of CCTA continue to have an excellent cardiac prognosis, while outcome is progressively worse in patients with nonobstructive and obstructive CAD

Design of, and enrollment in, the palliative care communication research initiative: A direct-observation cohort study

© 2015 Gramling et al.Background: Understanding the characteristics of communication that foster patient-centered outcomes amid serious illness are essential for the science of palliative care. However, epidemiological cohort studies that directly observ

Impact of a new motion-correction algorithm on image quality of low-dose coronary CT angiography in patients with insufficient heart rate control

RATIONALE AND OBJECTIVES: Prospective electrocardiogram (ECG) triggering allows coronary computed tomography angiography (CCTA) scanning with low radiation dose but requires heart rates below 63 beats/min. We assessed the impact of a novel vendor-specific motion-correction algorithm on image quality and interpretability of low-dose CCTA acquired despite insufficient heart rate control. MATERIALS AND METHODS: In 40 patients undergoing CCTA for the assessment of known or suspected coronary artery disease who did not reach the target heart rate below 63 beats/min despite β-blockade before prospective low-dose scanning, the temporal acquisition window was increased (80 ms additional padding). The new algorithm detects and integrates vessel path and velocity from adjacent cardiac phases for motion correction. Two blinded observers assessed image quality on a 4-point Likert scale (1, nonevaluative; 2, reduced but evaluative; 3, good; and 4, excellent) and the fraction of interpretable segments (score 2 or more) using motion correction versus standard reconstruction. RESULTS: Image reconstruction with motion correction resulted in an increased median coronary artery image quality score (excellent interobserver agreement, κ = 0.85) compared to standard reconstruction (3.4 vs. 3.0, P < .001). Consequently, motion-corrected reconstruction significantly improved the overall interpretability of coronary arteries (from 78% to 88%, P < .001). Estimated mean effective radiation dose was 2.3 ± 0.8 mSv. CONCLUSIONS: A novel, vendor-specific, motion-corrected, reconstruction algorithm improves image quality and interpretability of prospectively ECG-triggered low-dose CCTA despite insufficient heart rate control

Coronary computed tomography angiography with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination

AIMS: To evaluate the feasibility and image quality of coronary computed tomography angiography (CCTA) acquisition with a submillisievert fraction of effective radiation dose using model-based iterative reconstruction (MBIR) for noise reduction. METHODS AND RESULTS: In 42 patients undergoing standard low-dose (100-120 kV; 450-700 mA) and additional ultra-low-dose CCTA (80-100 kV; 150-210 mA) reconstructed with MBIR, segmental image quality was graded on a four-point scale [(i): non-evaluative, (ii): good, (iii): adequate, and (iv): excellent]. Signal-to-noise ratio (SNR) was calculated dividing left main artery (LMA) and right coronary artery (RCA) attenuation by the aortic root noise. Over a wide range of body mass index (18-40 kg/m(2)), the estimated median radiation dose exposure was 1.19 mSv [interquartile range (IQR): 1.07-1.30 mSv] for standard and 0.21 mSv (IQR: 0.18-0.23 mSv) for ultra-low-dose CCTA (P < 0.001). The median image quality score per segment was 3.5 (IQR: 3.0-4.0) in standard CCTA vs. 3.5 (IQR: 2.5-4.0) in ultra-low dose with MBIR (P = 0.29). Diagnostic image quality (scores 2-4) was found in 98.7 vs. 97.8% coronary segments (P = 0.36). Introduction of MBIR for ultra-low-dose CCTA resulted in a significant increase in SNR (P < 0.001) for LMA (from 15 ± 5 to 29 ± 7) and RCA (from 14 ± 4 to 27 ± 6) despite 82% dose reduction. CONCLUSION: Coronary computed tomography angiography acquisition with diagnostic image quality is feasible at an ultra-low radiation dose of 0.21 mSv, e.g. in the range reported for a postero-anterior and lateral chest X-ray

A PET/CT-follow-up imaging study to differentiate takotsubo cardiomyopathy from acute myocardial infarction

Takotsubo cardiomyopathy (TTC) is still an under-recognized disease and little data exists on the coexistence of TTC and obstructive coronary artery disease. Our patient case of an 80-year-old female lady highlights the impact of a positron emission tomography/computed tomography (PET/CT) follow-up imaging study to delineate this unique entity from acute coronary syndrome (ACS). Furthermore, we show for the first time that coronary flow reserve and myocardial blood flow is globally impaired in TTC and not only restricted to the non-contracting parts. This indicates a global microcirculatory impairment effect of the heart in the acute stage of TTC. Our case also demonstrates that a transient metabolic defect is also involved in this disease. Follow-up imaging by PET/CT in our patient case unmasked TTC and facilitated to exclude the differential diagnosis of ACS