The objective of this study was to investigate the incremental prognostic value for adverse events of myocardial blood flow (MBF) derived from stress computed tomography perfusion (CTP) at remote ...myocardium over cardiac risk factors and ischemia. We prospectively analyzed 242 patients who underwent dynamic CTP and CT angiography. Adverse events were defined as a composite of all-cause mortality, non-fatal myocardial infarction, unstable angina, heart failure requiring hospitalization, peripheral artery disease, and stroke. MBF value was calculated in each myocardial segment and ischemia was defined as mild decrease in MBF in two consecutive segments or moderate decrease in a single segment accompanied with a coronary stenosis ≥50%. The mean MBF of the non-ischemic segments was defined as remote MBF. We divided the patients into two groups by median MBF value of 1.15 ml/min/g. During a median follow-up of 18 months, 18 patients had adverse events. Annual event rate showed a significant difference between patients with low (≤1.15 ml/min/g) and high (>1.15 ml/min/g) MBF (6.1% vs 1.8%, p = 0.02). Univariate analysis showed that low MBF was a significant predictor of events (hazard ratio (HR): 3.4; 95% confidence interval (CI): 1.2 to 12.0; p = 0.02). This relationship maintained significant after adjusted for the presence of ischemia and cardiac risk factors (HR: 3.0; 95%CI: 1.1 to 11.1; p = 0.04). In conclusion, MBF value ≤1.15 ml/min/g derived from dynamic CTP in remote myocardium is significantly related with poor outcome and this relationship was independent of myocardial ischemia and cardiac risk factors.
To compare the diagnostic performance of estimated energy loss (EEL) with diameter stenosis (DS) to estimate significant stenosis by fractional flow reserve (FFR).
One hundred twenty-five patients ...were included. EEL was calculated using DS, lesion length, minimal lumen area and left ventricular volume. FFR ≤ 0.80 was determined significant.
EEL improved the accuracy from 63% (95% confidence interval (CI): 55–72%) to 83% (95% CI: 75–89%, p < 0.0001). EEL increased the area under the receiver operating characteristics curve from 0.63 to 0.85 (p < 0.0001).
EEL improved the diagnostic performance to detect functionally significant stenosis than DS.
•Estimated energy loss (EEL) increases with FFR reduction.•EEL could be calculated very easily without complex computation.•EEL could predict FFR ≤ 0.80 with an accuracy of 83%.•The best cutoff of EEL to predict FFR ≤ 0.80 was 1.17.•Ischemia analysis using coronary CT would become easier.
The objective of this study was to investigate the relationship of Hemoglobin A1c (HbA1c) and plaque characteristics including high risk plaque and plaque extent. We retrospectively examined 1079 ...consecutive coronary computed tomography (CT) angiography scans and the HbA1c results. We divided the patients into four groups by the HbA1c status: non-diabetic, ≤6.0; borderline, 6.1–6.4; diabetic low, 6.5–7.1; diabetic high, >7.1. We determined segment involvement score >4 as extensive disease. High risk plaque was defined as two feature positive (FP) plaque which consists of positive remodeling (remodeling index >1.1) and low attenuation (<30 HU). Univariate and multivariate analysis including conventional cardiovascular risk factors, symptoms and medication was performed. Univariate analysis showed that diabetic patients as well as borderline patients were significantly related with 2FP plaque and extensive disease. Although the relationship of borderline patients and 2FP plaque was marginal in multivariate analysis odds ratio (OR) 1.53, 95 % confidence interval (CI) 0.95–2.40,
p
= 0.07, the elevation of HbA1c was strongly associated with 2FP plaque (diabetic low, OR 2.19, 95 % CI 1.37–3.45,
p
< 0.005; diabetic high, OR 4.14, 95 % CI 2.57–6.67,
p
< 0.0005). The association of HbA1c elevation and extensive disease was quite similar between borderline and diabetic patients (borderline, OR 1.96, 95 % CI 1.29–2.95,
p
< 0.005; diabetic low, OR 1.94, 95 % CI 1.25–3.01,
p
< 0.005; diabetic high, OR 2.19, 95 % CI 1.39–3.43,
p
< 0.005). Patients with elevated HbA1c of >6.0 are potentially at risk for future cardiovascular events due to increased high risk plaque and extensive disease, even below the diabetic level of 6.5. Coronary CT could be used for risk stratification of these patients.
The objective of this study was to investigate the relationship between the severity of hepatic steatosis and coronary artery disease characteristics assessed by coronary computed tomography (CT) ...angiography. This retrospective analysis consisted of 2028 patients. Hepatic steatosis was evaluated by liver attenuation on unenhanced CT and the patients were divided into four groups (≥60 HU, 54–59 HU, 43–53 HU, ≤42 HU). Coronary calcification was calculated using the Agatston method. Obstructive disease was defined as ≥50 % stenosis assessed by CT. A high-risk plaque was defined by a remodeling index >1.1 and low attenuation (<30 HU). Patients with a segment involvement score >4 were determined to have extensive disease. Logistic regression analysis was performed to study multivariate associations. Severity of hepatic steatosis was associated with coronary calcification (
p
= 0.02), obstructive disease (
p
< 0.0001), presence of a high-risk plaque (
p
= 0.0001) and extensive disease (
p
= 0.001) in the univariate analysis. However, the relationships were attenuated in the multivariate analysis with the exception of obstructive disease (
p
= 0.04). Liver attenuation of <54 HU was significantly associated with obstructive coronary artery disease independent of conventional risk factors such as age, sex, diabetes mellitus, hypertension, dyslipidemia and smoking (hepatic attenuation 43–53 HU, odds ratio 1.52, 95 % confidence interval 1.11–2.10,
p
= 0.01; ≤42 HU, odds ratio 1.65, 95 % confidence interval 1.10–2.45,
p
= 0.02). Although conventional risk factors were stronger predictors of coronary calcification and plaque formation, the severity of hepatic steatosis remained an independent risk factor for obstructive coronary artery disease. Coronary CT angiography may play a potential role in risk stratification for patients with hepatic steatosis.
Background Several methods have been developed to reduce the radiation dose in coronary computed tomography angiography (CTA). Objective The objective of our study was to evaluate the effects of ...Adaptive Iterative Dose Reduction (AIDR) on objective and subjective image quality as well as the radiation dose, compared with conventional filtered back projection (FBP), in coronary CTA. Methods We retrospectively reviewed 100 consecutive patients who underwent coronary CTA. In the first 50 patients, a higher tube current was used, and images were reconstructed with FBP. In the last 50 patients, a lower tube current was used, and images were reconstructed with AIDR. Subjective and objective image quality (noise, signal-to-noise ratio, contrast-to-noise ratio) were assessed. Results The median radiation dose of the AIDR group was 22% lower than that of the FBP group (4.2 vs 5.4 mSv; P = 0.0001). No significant difference was found in subjective image quality, noise, signal-to-noise ratio, or contrast-to-noise ratio between the 2 groups. Conclusion AIDR reduced the tube current which resulted in reduction of radiation dose in coronary CTA while maintaining subjective and objective image quality compared with coronary CTA reconstructed with FBP.
To prospectively perform a decision and cost-effectiveness analysis of surgical and endovascular treatments of unruptured intracranial aneurysms, with incorporation of the results of the prospective ...International Study of Unruptured Intracranial Aneurysms.
With use of a Markov model, a decision and cost-effectiveness analysis was performed for comparison of surgical or endovascular treatment with no treatment. Twelve clinical scenarios were defined on the basis of aneurysm size and location. Probabilistic sensitivity analyses were performed for 50- and 40-year-old patient cohorts. Treatment was considered to be cost-effective at an incremental cost-effectiveness ratio less than $100,000 per quality-adjusted life-year.
In 50-year-old patients, no treatment was the most cost-effective strategy for aneurysms located in the cavernous carotid artery. For aneurysms smaller than 7 mm located in the anterior circulation, no treatment was the most cost-effective strategy. Endovascular treatment was the most cost-effective option for 7-24-mm aneurysms, whereas surgical treatment was the most cost-effective option for aneurysms 25 mm or larger. For aneurysms smaller than 7 mm or 25 mm or larger located in the posterior circulation, no treatment was the most cost-effective strategy. Surgical treatment was the most cost-effective option for 7-12-mm aneurysms, whereas endovascular treatment was the most cost-effective option for 13-24-mm aneurysms.
For 50-year-old patients, treatment of aneurysms that are small (<7 mm), that are located in the cavernous carotid artery, or that are large (>or=25 mm) and located in the posterior circulation is ineffective or not cost-effective.
Purpose
To clarify the workload of certified radiologists and to estimate the current manpower shortages in Japan.
Methods
We conducted a questionnaire survey for accredited training institutions. ...The contents included the radiologist employment pattern (full vs. part time), the number of computed tomography (CT) and magnetic resonance imaging (MRI) examinations and their radiology reports, the number of radiation therapy planning sessions, and the time per week spent for each work activity. We also used the hospital survey reports of Japan’s Ministry of Health, Labor, and Welfare in our analyses.
Results
The estimated numbers of CT and MRI interpretation reports and radiation treatment plans that one full-time radiologist could complete within 1 hospital day (8 h) were 19.9 and 1.22, respectively. To complete all CT and MRI reports, at least 2.09 times more full-time diagnostic radiologists are needed in Japan. For radiation therapy, at least 1.23 times more full-time radiation oncologists are necessary at large- and medium-scale hospitals, although the number of radiation oncologists needed in Japan is balanced to the current number.
Conclusion
The number of full-time certified diagnostic radiologists for CT and MRI interpretation in Japan is insufficient. Centralized radiation therapy facilities may be more efficient for meeting the increasing demand.
Dynamic myocardial computed tomography perfusion (CTP) is an emerging technique to diagnose significant coronary stenosis. However, this procedure has not been reported using single-source 64-row CT.
...To investigate the radiation dose and the diagnostic performance of dynamic CTP to diagnose significant stenosis by catheter exam.
We prospectively included 165 patients who underwent CTP exam under adenosine stress using a single-source 64-row CT. MBF was calculated using the deconvolution technique. Quantitative perfusion ratio (QPR) was defined as the myocardial blood flow (MBF) of the myocardium with coronary stenosis divided by the MBF of the myocardium without significant stenosis or infarct. Of the 44 patients who underwent subsequent coronary angiography, we assessed the diagnostic performance to diagnose ≥50% stenosis by quantitative coronary analysis (QCA).
The average effective dose of dynamic CTP and the entire scans were 2.5 ± 0.7 and 7.3 ± 1.8 mSv, respectively. The MBF of the myocardium without significant stenosis was 1.20 ± 0.32 ml/min/g, which significantly decreased to 0.98 ± 0.24 ml/min/g (p < 0.01) in the area with ≥50% stenosis by CT angiography. The QPR of the myocardium with QCA ≥50% stenosis was significantly lower than 1 (0.84 ± 0.32, 95% confidence interval (CI), 0.77–0.90, p < 0.001). The accuracy to detect QCA ≥50% stenosis was 82% (95%CI, 74–88%) using CT angiography alone and significantly increased to 87% (95%CI, 80–92%, p < 0.05) including QPR.
Dynamic myocardial CTP could be performed using 64-row CT with a low radiation dose and would improve the diagnostic performance to detect QCA ≥50% stenosis than CT angiography alone.
We performed dynamic myocardial computed tomography perfusion (CTP) using a single-source 64-row CT. The average effective dose of the entire scan was 7.3 ± 1.8 mSv. Quantitative perfusion reserve (QPR) was defined as the MBF of the myocardium with coronary stenosis divided by the remote MBF. The accuracy to detect ≥50% stenosis by quantitative coronary analysis by catheter exam was 82% using CT angiography alone and significantly increased to 87% (p < 0.05) including QPR. Dynamic CTP could be performed using 64-row CT with an acceptable radiation dose and improves the diagnostic performance to detect significant stenosis than CT angiography alone.
Abstract Background Thin-cap fibroatheroma (TCFA) is assumed to cause acute coronary syndromes. Objective To compare the accuracy of different models for diagnosing TCFA using parameters derived by ...CT, validated against optical coherence tomography (OCT). Methods One hundred twenty-nine plaques in 106 patients were analyzed using data acquired by 64-row CT with a reconstruction thickness of 0.67 mm and an increment of 0.33 mm. TCFA was defined by OCT as a plaque with lipid content in ≥2 quadrants and the thinnest part of the fibrous cap measuring ≤65 μm. The following parameters were obtained from CT: remodeling index (RI), proportion of low-attenuation (LA) volume (<60 HU), minimum CT number and napkin-ring sign (NRS). We compared three models to predict TCFA: Model 1, RI > 1.1, minimum CT number <30 HU and NRS; Model 2, RI > 1.1, minimum CT number <30 HU or NRS; Model 3, regression model using RI, proportion of LA volume and NRS. Results In OCT, 83 plaques fulfilled the criteria of TCFA. The area under the receiver operating characteristics curve significantly ( p < 0.01) increased to 0.96 (95% confidence interval (CI), 0.92–1.0) in model 3 as compared to models 1 (0.74, 95% CI, 0.68–0.80) and 2 (0.72, 95% CI, 0.67–0.79). Diagnostic accuracy of model 3 (93%) was significantly higher than that of models 1 (67%, p < 0.001) and 2 (80%, p = 0.001). Sensitivity and specificity of model 3 was 94% and 91%, respectively. Conclusion Diagnostic performance to identify TCFA by coronary CTA improves when RI and proportion of LA volume are used as continuous values rather than dichotomizing these parameters.
Objective: To derive and validate a formula to predict the optimal amount of contrast medium for coronary CT angiography (CTA) from CT perfusion (CTP) data during comprehensive cardiac CT.
Materials ...and Methods: The derivation and validation group consisted of 196 and 41 patients, respectively. Dynamic CTP was performed under adenosine triphosphate stress of 0.14 mg/kg/min, followed by rest coronary CTA. Time to peak (TTP) and peak enhancement (PE) in the left ventricle during CTP was recorded. The amount of contrast medium during CTA was 0.8×body weight (kg) in the derivation group. A formula to determine the amount of contrast medium needed to achieve an enhancement of 370 Hounsfield unit (HU) in CTA was derived using TTP, PE, body weight, and heart rate. The amount of contrast medium required during CTA in the validation group was determined by this formula.
Results: The mean amount of contrast medium during CTA did not differ between the derivation and validation groups (49.3±8.0 mL vs. 47.9±12.9 mL, p=0.39). The mean coronary artery enhancement was slightly lower in the validation group (400±55 HU vs. 380±46 HU, p=0.03) with smaller interpatient variability (p=0.02) than in the derivation group. The proportion of patients with an optimal enhancement of 320 HU to 420 HU significantly increased from 54% to 75% (p=0.01) when the formula was used.
Conclusion: Adjusting the amount of contrast medium using dynamic CTP data could reduce the interpatient variability of coronary enhancement during comprehensive cardiac CT. KCI Citation Count: 0
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