Quantitative analysis of coronary vessels with optimized intracoronary CT number.

BACKGROUND: Variability in intracoronary computed tomography (CT) number may influence vessel quantification. We confirmed the feasibility of a novel method for measuring vessel diameter and area using coronary CT angiography (CCTA) with an optimized intracoronary CT number, 350 HU. METHODS: We performed intravascular ultrasound (IVUS) imaging in 52 patients with significant stenosis detected by coronary CT angiography targeting 350 HU using a CT number-controlling system. We measured 0-to-0 HU distances in the cross-sectional coronary images of 32 patients. We analyzed the ratio of 0-to-0 HU distances in CT images to media-to-media distances in IVUS images (C:I ratio). The area of ≥0 HU for 103 representative points in the remaining 20 patients was compared to the area of the traced external elastic membrane (EEM) in IVUS images. RESULTS: There was a strong correlation between 0-to-0 HU distance in CT images and media-to-media diameter in IVUS images (r = 0.97, p<0.001). The C:I ratio was 1.1. EEM area was estimated by dividing the area of ≥0 HU by the square of C:I. There was also a strong correlation between the estimated EEM area and the EEM area in IVUS images (r = 0.95, p<0.001). CONCLUSIONS: Media-to-media diameter and EEM area can be estimated by CCTA targeting the optimized intracoronary CT number when blood vessel borders are defined at 0 HU.

CT number-controlling system for reproducibility of intracoronary CT number on follow-up coronary CT angiography.

BACKGROUND: Coronary computed tomography angiography (CCTA) may be useful for noninvasive follow-up; however, evaluation of coronary stenosis and CT number of plaque may be inaccurate under different vessel enhancement of contrast media. We examined the reproducibility of the CT number of repeat CCTA using our original CT number-controlling system (CTN-CS), which selects contrast level by a multiple regression equation using body surface area and peak CT number and peak time on timing bolus and during CCTA. METHODS AND RESULTS: One hundred seventy-two patients who underwent serial CCTA were prospectively and randomly assigned to 3 groups. In the first group, Group A, the amount of contrast for the second CCTA was determined by CTN-CS to match the intracoronary CT number of the first CCTA. In Group B, each patient received the same amount of intravenous contrast in both CCTA examinations. In Group C, 0.7 mL/mg body weight (BW) of contrast medium (350 mgI/mL) was used for baseline and follow-up CCTAs. The regression of repeated CCTAs was the best in Group A (r=0.85, p<0.001) vs. Group B (r=0.52, p<0.001), and Group C (r=0.61, p<0.001). The absolute difference between intracoronary CT numbers of the second and first CCTA was the lowest in Group A (24.8 ± 21.8HU), followed by Group B (37.6 ± 26.2 HU; p<0.05) and Group C (46.5 ± 34.4HU; p<0.001). CONCLUSIONS: Using CTN-CS, the difference of intracoronary CT numbers of the second and first CCTA was the smallest when compared to CCTAs using the same contrast volumes or constant volumes per body weight.

Coronary computed tomography angiography using ultra-low-dose contrast media: radiation dose and image quality.

To analyze the invasiveness and image quality of coronary CT angiography (CCTA) with 80 kV. We enrolled 181 patients with low body weight and low calcium level. Of these, 154 patients were randomly assigned to 1 of 3 groups: 280 HU/80 kV (n = 51); 350 HU/80 kV (n = 51); or 350 HU/120 kV (n = 52). The amount of contrast media (CM) was decided with a CT number-controlling system. Twenty-seven patients were excluded because of an invalid time density curve by timing bolus. The predicted amount of CM, volume CT dose index, dose-length product, effective dose, image noise, and 5-point image quality were measured. The amounts of CM for the 80 kV/280 HU, 80 kV/350 HU, and 120 kV/350 HU groups were 10 ± 4 mL, 15 ± 7 mL, and 30 ± 6 mL, respectively. Although image noise was greater at 80 than 120 kV, there was no significant difference in image quality between 80 kV/350 HU and 120 kV/350 HU (p = 0.390). There was no significant difference in image quality between 80 kV/280 HU and 80 kV/350 HU (4.4 ± 0.7 vs. 4.7 ± 0.4, p = 0.056). The amount of CM and effective dose was lower for 80 kV CCTA than for 120 kV CCTA. CCTA at 80 kV/280 HU may decrease the amount of CM and radiation dose necessary while maintaining image quality.

Controlling intracoronary CT number for coronary CT angiography.

BACKGROUND: Controlling intracoronary computed tomography (CT) number for coronary CT angiography (CCTA) has been difficult. OBJECTIVE: The study assessed whether intracoronary CT number of CCTA could be estimated. METHODS: One hundred twenty six patients were randomly assigned to either CCTA with 30 mL of contrast media (CM) following 5 mL of CM at timing bolus or CCTA with 50 mL of CM following 10 mL of CM at timing bolus. The relationships between intracoronary CT number and patients' characteristics and peak time and peak CT number at timing bolus in patients who showed valid time-density curve were analyzed in both groups. Then, the multiple regression equation best described was made. The prediction system was validated by 112 patients randomly targeted between 250 HU and 430 HU of CT number. RESULTS: In group 5/30, intracoronary CT number was positively correlated with peak CT number at timing bolus (correlation coefficient, 1.42, p<0.001), negatively correlated with body surface area (-109.19, p<0.001) and peak time (-6.93, p<0.001). Whereas, intracoronary CT number was positively correlated with only peak CT number at timing bolus (1.33, p<0.001) in group 10/50. Then, CT number-controlling system using the simple equation best described CT number was established for CCTA following 5 mL of CM at timing bolus. Of 112 patients, there was good correlation between target CT number and measured CT number (r=0.85, p<0.0001) in 96 patients (85.7%), having valid time-density curve at timing bolus. CONCLUSIONS: Controlling CT number may be enabled by CT number-controlling system following 5 mL of CM at timing bolus.

Visceral abdominal fat accumulation predicts the progression of noncalcified coronary plaque.

BACKGROUND: Excess visceral abdominal tissue (VAT) is more strongly associated with risk factors of coronary artery disease (CAD) than body mass index (BMI) or waist circumference. However, whether adding VAT measurements to CAD risk factors provides better risk assessment for CAD progression has not been fully evaluated. METHODS AND RESULTS: This prospective cohort study comprised 553 CAD patients with coronary plaque with ≤50% coronary stenosis as assessed by computed tomography (CT) angiography. Quantification of VAT area was performed together with CT angiography using abdominal CT scanning. After a mean 38±8 months follow-up, 320 patients underwent repeated CT scans for worsening angina symptoms without findings of positive ischemia. Increased segments of noncalcified plaque were seen in 152 (48%) and an increased calcium score was seen in 261 (82%) patients. The risk for progression of noncalcified plaque increased steadily with higher VAT quartiles, independent of CAD risk factors. Patients in the higher quartiles were at increased risk of progression of noncalcified plaque (quartiles IV OR 4.7; 95% CI 2.3-9.4, p-value<0.001). In contrast, increases above the median calcium score showed no independent correlation to VAT. Compared to VAT, progression of noncalcified plaque showed no phased increase with higher waist circumference and weaker increase with higher BMI quartiles. CONCLUSION: VAT accumulation was positively associated with progression of coronary noncalcified plaque, but not of calcified plaque. This suggests that risk assessment of progression of noncalcified plaque can be improved by combining VAT measurements and CAD risk factors.

Serum cystatin C is associated with early stage coronary atherosclerotic plaque morphology on multidetector computed tomography.

OBJECTIVE: Cystatin C, a novel marker of kidney function, has been reported to be a predictor of adverse cardiovascular outcomes in patients without established chronic kidney disease. However, the relationship between serum cystatin C concentrations and early stage coronary atherosclerotic plaque morphology among patients with preserved kidney function has not been fully evaluated. METHODS AND RESULTS: 405 outpatients with early coronary artery disease with estimated glomerular filtration rate (eGFR) ≥ 60ml/min/1.73m(2) and <50% stenosis on 64-slice CT coronary angiography were enrolled. Subjects were categorized into quartiles by serum cystatin C (quartile I: ≤ 0.88mg/L - quartile IV: ≥ 1.16mg/L). Plaques in coronary segments were categorized as calcified or noncalcified. Multiple linear regression analysis revealed that lower eGFR, higher age, increasing numbers of noncalcified and calcified plaques, lower high-density lipoprotein cholesterol, and female gender were statistically significant predictors of increased cystatin C concentrations. The risk for presence of noncalcified plaques increased significantly with increasing quartiles of cystatin C. Compared with those in the lowest quartile, patients in each subsequent quartile were at steadily increased risk of having noncalcified plaque (quartile IV: OR 5.6; 95% CI 2.3-13.9, p-value <0.001). Both number of segments with calcified plaque and Agatston score were highly correlated with cystatin C concentrations (both p<0.001), but when adjusted for segments with noncalcified plaque and other risk factors, calcified plaque segments were no longer independently predictive. CONCLUSION: Higher serum cystatin C concentrations were correlated with early stage coronary atherosclerotic plaques among patients without established chronic kidney dysfunction. Noncalcified plaques increased with serum cystatin C concentrations, an association independent of eGFR and other cardiovascular risk factors.

Idiopathic pulmonary vein thrombosis complicated with old myocardial infarction detected by multidetector row computed tomography.

Pulmonary vein thrombosis is rarely detected in patients with cancer, lung lobectomy, trauma and so on. We report the case of idiopathic pulmonary vein thrombosis complicated with coronary heart disease. A-57-year-old man with suspected coronary heart disease underwent computed tomography coronary angiography. He did not show any sign of malignancy in lung or other organs. Multi-detector row computed tomography demonstrated 3-dimensional images for the thrombi in bilateral lower pulmonary veins besides an old anterior myocardial infarction. Previously, few reports have described the detection of pulmonary vein thrombosis, however, multi-detector row computed tomography was thought to be useful for detecting and evaluating pulmonary vein thrombosis.