Impact of Abnormal Remote Stress Myocardial Blood Flow by Dynamic CT Perfusion on Clinical Outcomes.

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.

Double region of interest timing bolus technique following endovascular aortic repair: Short-term prognosis analysis.

OBJECTIVES: To compare the incidence rate of reintervention in patients with and without complication findings at aortic computed tomography using double region of interest timing bolus (DRTB) method after endovascular stent placement of the aorta. METHODS: We included 40 patients who underwent computed tomography of the aorta using DRTB method after endovascular stent placement. DRTB method allows to scan the aorta with a short injection time of 9 s by synchronizing the scan speed to the aortic flow. Complication findings at computed tomography were defined as endoleak, rupture, occlusion, and infection. The primary endpoint was reintervention, which was defined as any of the following three events: conversion to open repair, graft revision, or secondary intervention. RESULTS: The mean contrast medium during computed tomography angiography was 38.6 ± 3.9 mL. Complication findings at computed tomography were present in 10 patients (25%): endoleak (n = 9) and infection (n = 1). During a median follow-up of 7 months (interquartile range, 4-11 months), two patients experienced reintervention. Kaplan-Meier curves by complication findings showed that event rate at 6 months was significantly higher in patients with complication findings than in patients without (20% vs 0%, p = 0.01). No patients without complication findings at computed tomography experienced reintervention. CONCLUSIONS: No complication findings at computed tomography after intervention of the aorta resulted in good prognosis in patients who underwent aortic computed tomography using DRTB method.

Aortic CT angiography using the double region of interest timing bolus technique: feasibility of 80 kVp scanning in lean patients.

To investigate the feasibility of aortic computed tomography angiography (CTA) performed at 80 kVp in lean patients using the double region of interest timing bolus (DRTB) technique compared to 100 kVp scanning. This study was approved by the institutional ethics committee, and all patients provided written informed consent. We prospectively included 165 patients from July 2018 to February 2019. We used an 80 kVp protocol when the maximal tube current did not exceed the limit using automatic exposure control; otherwise, 100 kVp was selected. The scan parameters for aortic CTA were determined from the test scan data. Enhancement at six points of the aortoiliac arteries and noise at the bifurcation level were measured. We compared the enhancement and signal to noise ratio (SNR) using Student's t-test. The tube voltage was 80 kVp in 87 patients (53%). The enhancement of the aortoiliac arteries was significantly higher (449.3 ± 77.8 vs 378.7 ± 53.1 HU, p < 0.0001) and the SNR was similar (42.4 ± 11.1 vs 40.0 ± 10.6, p = 0.17), and the amount of contrast medium was lower (33.0 ± 2.5 vs 41.8 ± 3.3 ml, p < 0.001) in the 80 kVp group compared to the 100 kVp group. Reducing the tube current to 80 kVp could decrease the amount of contrast medium used compared to the 100 kVp protocol, while maintaining image quality, for aortic CTA using the DRTB technique.

Double ROI Timing Bolus Technique to Perform Aortic CT Angiography With a 9-Second Contrast Injection Duration.

OBJECTIVE. The purpose of this study was to investigate the feasibility of a double ROI timing bolus technique for performing aortic CT angiography (CTA) with 40 mL of contrast medium over 9 seconds. SUBJECTS AND METHODS. A prospective study from February to July 2018 included 106 patients with clinical indications for evaluation of aortic aneurysm or dissection or suspected aortic disease. Forty-seven of these patients had undergone prior aortic CTA by the conventional method. The scanning speed for the double ROI timing bolus technique was calculated from the time-attenuation curves of the ascending and descending aorta by use of the timing bolus data to synchronize aortic flow. The conventional scan was obtained by injection of 1.7 mL of contrast medium per kilogram of body weight for 25 seconds. Enhancement of six points on the aortoiliac arteries and superior vena cava was measured. The t test was used to compare the values. RESULTS. Use of the double ROI timing bolus method significantly reduced the amount of contrast medium injected compared with the amount for the conventional method (40.0 mL vs 88.0 ± 9.4 mL, p < 0.001). Use of the method significantly increased aortoiliac enhancement (403.3 ± 76.0 HU vs 359.7 ± 61.5 HU, p < 0.001) and significantly decreased enhancement of the superior vena cava (118.9 ± 46.2 HU vs 239.2 ± 130.5 HU, p < 0.001) compared with the conventional method. In the group with prior CTA images available, the effective dose was significantly lower with the double ROI timing bolus than with the conventional method (8.3 ± 1.7 mSv vs 12.4 ± 3.2 mSv, p < 0.01). CONCLUSION. Use of the double ROI timing bolus method can dramatically reduce the amount of contrast medium used during aortic CTA while improving aortic enhancement and reducing radiation dose.

Feasibility of dynamic myocardial CT perfusion using single-source 64-row CT.

BACKGROUND: 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. OBJECTIVE: To investigate the radiation dose and the diagnostic performance of dynamic CTP to diagnose significant stenosis by catheter exam. METHODS: 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). RESULTS: The average effective dose of dynamic CTP and the entire scans were 2.5 ±â€¯0.7 and 7.3 ±â€¯1.8 mSv, respectively. The MBF of the myocardium without significant stenosis was 1.20 ±â€¯0.32 ml/min/g, which significantly decreased to 0.98 ±â€¯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 ±â€¯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. CONCLUSION: 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.

Data for comparison of computed tomography angiography and dynamic myocardial perfusion to detect significant stenosis by coronary angiography.

This article describes data related to a research article titled "Feasibility of dynamic myocardial CT perfusion using single-source 64-row CT", Tomizawa et al. (in press) [1]. Decrease in the myocardial blood flow could be calculated by performing stress dynamic computed tomography perfusion. This article compares the receiver operating characteristics curve of computed tomography angiography and dynamic myocardial perfusion to diagnose significant stenosis by invasive coronary angiography.

Longer diabetes duration reduces myocardial blood flow in remote myocardium assessed by dynamic myocardial CT perfusion.

AIMS: To investigate the relationship of type 2 diabetes duration and myocardial blood flow (MBF) assessed by myocardial CT perfusion. MATERIALS AND METHODS: We prospectively included 140 patients with type 2 diabetes who underwent dynamic myocardial CT perfusion exam. MBF of the remote myocardium was calculated using the deconvolution technique and the Voronoi method. The relationships of MBF and diabetic duration, diabetic complications, conventional risk factors, coronary calcium, and coronary stenosis were assessed by logistic regression analysis. RESULTS: A weak but significantly negative relationship was present between diabetes duration and MBF (R2 = 0.05, p < 0.01). The average MBF of patients with a duration of >8 years was 13% lower than that of the remaining patients (1.11 ±â€¯0.35 vs 1.28 ±â€¯0.27 ml min-1 g-1, p < 0.01). Duration of one year was associated with a 6% increased risk for low MBF (<1.18 ml min-1 g-1) (odds ratio 1.06, 95% confidence interval 1.01-1.12, p < 0.05). Calcium score was also a significant factor for low MBF (odds ratio 1.08 (per 100 Agatston units), 95% confidence interval 1.01-1.17, p < 0.05). CONCLUSION: Longer diabetes duration is associated with lower MBF independent of conventional cardiac risk factors or the presence of coronary stenosis.

Simplified Bernoulli formula to predict flow limiting stenosis at coronary computed tomography angiography.

OBJECTIVE: To compare the diagnostic performance of estimated energy loss (EEL) with diameter stenosis (DS) to estimate significant stenosis by fractional flow reserve (FFR). MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: EEL improved the diagnostic performance to detect functionally significant stenosis than DS.

High-risk Plaque and Calcification Detected by Coronary CT Angiography to Predict Future Cardiovascular Events After Percutaneous Coronary Intervention.

RATIONALE AND OBJECTIVES: The purpose of this study was to investigate whether high-risk plaque (HRP) and calcium assessed by coronary computed tomography (CT) could predict future cardiovascular events after second-generation drug-eluting stent (DES) placement. MATERIALS AND METHODS: We analyzed 317 patients from December 2012 to April 2015 who underwent coronary CT followed by DES placement. HRP was defined as a plaque with positive remodeling and low attenuation or a plaque with a napkin-ring sign. Coronary calcium was assessed by Agatston score (AS). Patients were divided into three groups: low risk, HRP negative and AS <400; intermediate risk, HRP positive and AS ≥400; high risk, HRP positive and AS ≥400. The primary end point was a composite of all-cause mortality, myocardial infarction, fatal arrhythmia, or repeated revascularization. Kaplan-Meier analysis was used to estimate the distribution of time to events. RESULTS: A total of 74 events (23%) occurred during a median follow-up of 25.8 months. Patients with primary end points had HRP more frequently (70% vs 51%, P = 0.003) and were more calcified (AS, 471 [interquartile range, 143-1614] vs 289 [interquartile range, 63-787]; P = 0.01) than patients without primary end points. The frequency of primary end point increased significantly in the intermediate- and high-risk patients (P = 0.0011). Multivariate analysis showed that the hazard ratio of the intermediate- and high-risk groups was 1.91 (95% confidence interval, 1.04-3.77; P = 0.037) and 2.66 (95% confidence interval, 1.27-5.73; P = 0.009), respectively. CONCLUSION: Plaque and calcification analysis by coronary CT could predict future cardiovascular events after second-generation DES placement.

Decreased N-Acetyl Aspartate/Myo-Inositol Ratio in the Posterior Cingulate Cortex Shown by Magnetic Resonance Spectroscopy May Be One of the Risk Markers of Preclinical Alzheimer's Disease: A 7-Year Follow-Up Study.

Although molecular positron emission tomography imaging of amyloid and tau proteins can facilitate the detection of preclinical Alzheimer's disease (AD) pathology, it is not useful in clinical practice. More practical surrogate markers for preclinical AD would provide valuable tools. Thus, we sought to validate the utility of conventional magnetic resonance spectroscopy (MRS) as a screening method for preclinical AD. A total of 289 older participants who were cognitively normal at baseline were clinically followed up for analysis of MRS metabolites, including N-acetyl aspartate (NAA) and myo-inositol (MI) in the posterior cingulate cortex (PCC) for 7 years. The 289 participants were retrospectively divided into five groups 7 years after baseline: 200 (69%) remained cognitively normal; 53 (18%) developed mild cognitive impairment (MCI); 21 (7%) developed AD; eight (2%) developed Parkinson's disease with normal cognition, and seven (2%) developed dementia with Lewy bodies (DLB). The NAA/MI ratios of the PCC in the AD, MCI, and DLB groups were significantly decreased compared with participants who maintained normal cognition from baseline to 7 years after baseline. MMSE scores 7 years after baseline were significantly correlated with MI/Cr and NAA/MI ratios in the PCC. These results suggest that cognitively normal elderly subjects with low NAA/MI ratios in the PCC might be at risk of progression to clinical AD. Thus, the NAA/MI ratio in the PCC measured with conventional 1H MRS should be reconsidered as a possible adjunctive screening marker of preclinical AD in clinical practice.

Appropriate imaging utilization in Japan: a survey of accredited radiology training hospitals.

PURPOSE: To survey whether imaging is being performed appropriately in Japan, and to survey whether radiologists intervene to ensure imaging requests are appropriate. METHODS: An online survey was sent to radiologists at accredited radiology training hospitals. The survey included the radiologists' perspectives on whether imaging is performed appropriately at their institutions and whether they intervene if the indication for imaging is inappropriate/ambiguous. RESULTS: The response rate was 87.3% (165/189). We observed marked variability in the frequencies that imaging not recommended by the guidelines was performed among modalities and/or body parts; the responses "very frequently/frequently performed" were more common for breast cancer related imaging examinations and for head CT/MRI. The respondents frequently reported that inappropriate/ambiguous indications included requests to expand the craniocaudal range or to perform whole-body imaging. In 80% of the hospitals (132/165), radiologists contacted the physicians who requested unrecommended examinations; the number of CT and MRI examinations that full-time radiologists need to interpret in a half-day session was significantly smaller at these hospitals (median 18 vs 24, P = 0.032). CONCLUSION: We conducted a survey to investigate appropriate imaging utilization in Japan. At the hospitals with numerous examinations to interpret, full-time radiologists may find it difficult to ensure that examinations are ordered appropriately.

Accuracy of computed tomography angiography to identify thin-cap fibroatheroma detected by optical coherence tomography.

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.

A clinical model to identify patients with high-risk plaque by coronary computed tomography angiography.

OBJECTIVES: Current clinical models predict the pre-test probability of obstructive coronary artery disease, but these models do not predict the presence of high-risk plaques. Thus the objective of this study was to propose a model to predict high-risk plaque assessed by coronary computed tomography (CT) angiography. METHODS: This study was a retrospective cross-sectional study. A clinical model was derived from 2392 patients and verified by 733 patients who underwent coronary CT suspected of coronary artery disease. High-risk plaque was defined as a plaque with positive remodeling (remodeling index>1.1), low attenuation (<30Hounsfield units) and napkin-ring sign. The risk score was calculated from the following 6 variables with a maximum of 24 points: age, sex, hemoglobin A1c, systolic blood pressure, high-density lipoprotein and smoking status. RESULTS: The proportion of patients with high-risk plaque was 11% and 17% in the derivation and validation cohort, respectively. The area under the receiver operation characteristic curve was 0.71 (95% confidence interval (CI): 0.68 to 0.74) in the derivation cohort and 0.75 (95% CI: 0.70 to 0.79) in the validation cohort. The frequency of high-risk plaques was 4% in the low-risk group (≤8 points) while it was 53% in the high-risk group (≥17 points) of the derivation cohort. CONCLUSIONS: We propose a scoring system to detect high-risk plaque assessed by coronary CT. Patients in the high-risk group have a high prevalence of high-risk plaque and might benefit from lipid lowering therapy.

Relationship of hepatic steatosis severity and coronary artery disease characteristics assessed by coronary CT angiography.

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.

The association of hemoglobin A1c and high risk plaque and plaque extent assessed by coronary computed tomography angiography.

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.

High prevalence of coronary artery events and non-coronary events in patients with coronary artery aneurysm in the observational group.

BACKGROUND: Coronary artery aneurysm (CAA) is occasionally detected on a small percentage of coronary angiography or multi-detector computed tomography (MDCT). CAA itself is considered benign entity despite the potential risks of rupture, thromboembolism, and compression of surrounding structures. However, the optimal management including other vascular comorbidity has yet to be fully clarified. OBJECTIVE: The aim of this study was to evaluate cardiovascular events in the patients with CAA in the observational group. METHODS: Between January 2010 and August 2015, 48 CAAs were identified in 37 patients out of consecutive 10,010 patients (0.37%) by MDCT. Twenty-eight patients treated conservatively were included in this study. Their major adverse cardiovascular events (MACE) were evaluated retrospectively: death, non-fatal myocardial infarction (MI), revascularizations; coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI), and other vascular events. RESULTS: The average age was 62.0 ± 15.5 year sold, and median follow-up period was 49.6 months (IQR 23.6 to 78.1). Mean CAA diameter was 7.5 ± 2.8 mm. Twenty-two MACE occurred in 15 patients (53.6%): 1 sudden death, 4 MI, 1 CABG for CAA, 3 PCI for CAA, 7 PCI for non-CAA lesions, and 6 other vascular treatments for aorta and cerebral and peripheral artery. Follow-up MDCT was performed for 22 CAAs in 16 patients. In 9 CAAs of them, the maximal diameter increased significantly (Δ diameter: 1.5 ± 1.1 mm). CONCLUSIONS: Presence of CAA may be associated with adverse vascular events including non-coronary diseases. This study could suggest the management for CAA should include the evaluation of not only CAA itself but also other vascular diseases.

Current radiologist workload and the shortages in Japan: how many full-time radiologists are required?

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.

Difference of coronary artery disease severity, extent and plaque characteristics between patients with hypertension, diabetes mellitus or dyslipidemia.

The purpose of this study was to investigate the difference of coronary artery disease (CAD) severity and extent as well as plaque characteristics between patients with either one of hypertension (HT), diabetes mellitus (DM) or dyslipidemia (DL). We retrospectively reviewed the records of 1,161 patients (HT 442, DM 77, DL 248, no disease 394) who underwent coronary computed tomography angiography. Stenosis severity was classified as normal, non-obstructive (1-49 % stenosis), moderate (50-69 % stenosis) or severe (≥70 % stenosis). Segment involvement score (SIS) and segment severity score (SSS) was calculated. We defined patients at risk as patients with obstructive CAD or non-obstructive CAD with extensive disease (SIS ≥ 5). Plaque characteristics were evaluated including positive remodeling, low attenuation and spotty calcification. Obstructive CAD was most frequent in DM patients, followed by HT and DL patients (34, 19 and 15 %, respectively, p < 0.0001). DM patients had more extensive disease than HT and DL patients (SIS 3.1 vs 2.1 vs 1.4, SSS 4.0 vs 2.7 vs 2.0). DM patients were more at risk than HT and DL patients (p < 0.05). The prevalence of positive remodeling, low attenuation and spotty calcium were all highest in DM patients (p < 0.005, vs HT and DL), while low attenuation was more frequent in DL than HT patients (p < 0.005). The median calcium score of HT and DM patients were higher than DL patients (p < 0.01 and p < 0.005, respectively), while no significant difference was observed between HT and DM patients. In conclusion, DM patients possessed more high risk plaque and obstructive as well as extensive CAD compared with HT and DL patients. Coronary calcification was similarly high in HT and DM patients. Low attenuation plaque was more frequent in DL than HT patients.

Improving the diagnostic performance of the real world coronary computed tomography angiography including uninterpretable segments.

OBJECTIVES: The purpose was to investigate the diagnostic performance of coronary computed tomography angiography (CTA) when non-calcified uninterpretable segments were determined as either obstructive or patent. We also investigated the factors that could improve the diagnosis of CTA. METHODS: A total of 268 patients without known coronary artery disease who were clinically indicated for coronary angiogram (CAG) within 50days of coronary CTA were retrospectively included. The diagnostic performance of CTA was assessed with CAG as a reference, whereas stenosis of ≥50% was considered obstructive. We compared the results when non-calcified uninterpretable segments were determined as obstructive or patent. Coronary risk factors as well as contrast medium arrival time adjusted by heart rate (CATHR) were investigated for improvement of CTA diagnosis. RESULTS: Area under the receiver operating characteristic curve (AUC) improved when uninterpretable segments were determined as patent rather than obstructive (0.79 vs 0.73, p=0.02). Multivariate analysis showed that CATHR was a predictor of CAG stenosis (odds ratio 1.13, p=0.046) while other risk factors were not. Adding CATHR further improved the AUC to 0.82 (p=0.003). The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of CTA stenosis (uninterpretable segments as obstructive) were 72%, 99%, 32%, 68% and 95%. The values were 78%, 89%, 61%, 77% and 80% when CATHR was added and uninterpretable segments determined as patent. CONCLUSIONS: The diagnostic performance of coronary CTA improved when non-calcified uninterpretable segments were determined as patent rather than obstructive. Adding CATHR could further improve the specificity.