Coronary Coronary Computed Tomography Research Articles

Effects of Iterative Reconstruction Algorithm, Automatic Exposure Control on Image Quality, and Radiation Dose: Phantom Experiments with Coronary CT Angiography Protocols

†† ‡ § ‡ § In this study, we investigated the effects of an iterative reconstruction algorithm and an automatic exposure control (AEC) technique on image quality and radiation dose through phantom experiments with coronary computed tomography (CT) angiography protocols. We scanned the AAPM CT performance phantom using 320 multi-detector-row CT. At the tube voltages of 80, 100, and 120 kVp, the scanning was repeated with two settings of the AEC technique, i.e., with the target standard deviations (SD) values of 33 (the higher tube current) and 44 (the lower tube current). The scanned projection data were reconstructed also in two ways, with the filtered back projection (FBP) and with the iterative reconstruction technique (AIDR-3D). The image quality was evaluated quantitatively with the noise standard deviation, modulation tr ansfer function, and the contrast to noise ratio (CNR). More specifically, we analyzed the influences of selection of a tube voltage and a reconstruction algorithm on tube current modulation and consequently on radiation dose. Reduction of image noise by the iterative reconstruction algorithm compared with the FBP was revealed eminently, especially with the lower tube current protocols, i.e., it was decreased by 46% and 38%, when the AEC was established with the lower dose (the target SD=44) and the higher dose (the target SD=33), respectively. As a side effect of iterative reconstruction, the spatial resolution was decreased by a degree that could not mar the remarkable gains in terms of noise reduction. Consequently, if coronary CT angiogprahy is scanned and reconstructed using both the automatic exposure control and iterative reconstruction techniques, it is anticipated that, in comparison with a conventional acquisition method, image noise can be reduced significantly with slight decrease in spatial resolution, implying clinical advantages of radiation dose reduction, still being faithful to the ALARA principle.

Multislice CT coronary angiography is an additional tool for provisional diagnosis of acute chest pain with neither ECG nor echocardiography significant findings in emergency room

Background Multislice coronary computed tomography (CT) angiography is used to diagnose coronary artery disease (CAD) with good spatial and temporal resolution. Objective The aim of this study was to assess the uses of thin-slice multidetector row CT in the diagnosis of different vascular coronary causes of chest pain. Patients and methods A total of 20 patients were examined with full history taking, resting 12-lead ECG, cardiac biomarkers, and echocardiography. Thereafter, on the basis of their clinical manifestations or suspected progression of past condition they were enrolled for 160-multislice CT angiography using Ultravist 370 as a contrast medium. Results CT coronary angiography revealed the following: two cases were normal, two showed nonsignificant CAD, three showed significant CAD, 10 showed mild-to-moderate CAD, two showed anomalous coronary arteries, and one showed myocardial bridge. Conclusion CT angiography nowadays is considered the primary tool of diagnosis for different thoracic vascular disorders, being a safe, rapid method of diagnosis. Multislice coronary CT is a relatively new technique that gives physicians the advantage of screening emergency patients presenting with acute chest pain in a rapid and safe way for detection of their vascular diseases.

Optimized Subtraction Coronary CT Angiography Protocol for Clinical Use with Short Breath-Holding Time—Initial Experience

Subtraction coronary computed tomography (CT) angiography (CCTA), which enables the removal of calcium and coronary stents from CCTA images, has been clinically introduced on a second-generation 320-row CT scanner. However, this technique for clinical use is not optimized. The long breath-holding time for two data acquisitions, which causes image misregistration and patient's discomfort, may limit the clinical availability of this subtraction technique. This study received approval from the institutional review board; prior informed consent to participate was obtained from all patients. We performed subtraction CCTA of five patients using the test injection method and optimized the interval time between the first (pulmonary-arterial phase) and the second (coronary-arterial phase) scans to achieve robust subtraction. The patients' breath-holding times were recorded. We compared breath-holding times between our new protocol and previous study's protocol (estimated). Mean breath-holding time in our new protocol was 18.3±3.4 seconds and that in previous protocol was 29.8±3.6 seconds (difference in mean breath-holding time was 11.5 seconds). Misregistration artifacts were not shown in final subtraction CCTA images. These images improved luminal visualization in the calcified lesion. Our test injection protocol can shorten the breath-holding time, which is helpful for successful subtraction CCTA imaging, potentially resulting in an increase of subtraction CCTA examinations in many institutions.

Contrast material and radiation dose reduction strategy for triple-rule-out cardiac CT angiography: feasibility study of non-ECG-gated low kVp scan of the whole chest following coronary CT angiography

Dedicated coronary computed tomography (CT) scan has been proven to be an accurate diagnostic modality in evaluating coronary artery disease. A second phase scan starting immediately after the coronary CT scan might enable visualization of the different vascular territories of the entire chest. To investigate the feasibility of a contrast material and radiation dose reduction triple-rule-out (TRO) CT angiography (CTA) protocol with serial non-ECG-gated low kVp scan of the whole chest, which utilizes a recirculated contrast agent. Thirty patients were scanned with the new TRO-CTA protocol; after the coronary scan with retrospective ECG-gating, non-ECG-gated whole-chest CTA was performed at 80 kVp to evaluate aortic arch (AAr) and pulmonary trunk (PT). Another 30 patients were scanned by our conventional TRO-CTA protocol at 120 kVp with retrospective ECG-gating. We compared the estimated effective dose (ED), contrast material (CM) dose, contrast-to-noise ratio (CNR) of the ascending aorta (AAo), and the rate of patients who could achieve adequate attenuation of the AAr and PT between the two protocols. The total ED of the new TRO-CTA protocol was 29.6% lower than that of the conventional protocol (P < 0.01). The amount of CM used for the new TRO-CTA protocol was significantly lower than in the conventional protocol (60.1 ± 9.6 mL vs. 91.8 ± 22.6 mL, P < 0.01). The CNR of the AAo was 30.2% higher with the new TRO-CTA protocol than with the conventional protocol (P < 0.01). There was no significant difference in the success rate of adequate attenuation of the AAr and PT between the two protocols (P > 0.05). The new TRO-CTA protocol can reduce the total dose of radiation and the contrast dose and yield adequate vascular enhancement compared with the conventional protocol.

Presumed IgG4-Related Disease Presented as Coronary Periateritis: A Case Report Showing Dramatic Response to Steroid Therapy

A 54-year-old man underwent a coronary computed tomographic (CT) angiogram for a health check-up, and a soft tissuemass surrounding the right coronary artery was observed in the right atrioventricular groove. Moderate degree of multifocalstenoses were also noted in the left coronary artery. The serum concentration of immunoglobulin G4 was significantly increasedat 1569 mg/dl. In suspicion of IgG4-related periarteritis, he was treated with steroids. Two months after steroid therapy,coronary CT angiography revealed interval improvement of coronary periarteritis.

Heart rate control with single administration of a long-acting β-blocker at bedtime before coronary computed tomography angiography

BackgroundBeta-blockers are used to control the heart rate prior to coronary computed tomography (CT) angiography. However, in-hospital administration is time-consuming, and it is hard to decrease the heart rate to <60 beats per minute (bpm) when the initial heart rate is increased. In this study, we examined whether the single administration of long-acting β-blocker at bedtime before angiography is effective for achieving the target heart rate. Methods and resultsA total of 314 consecutive patients with a resting heart rate >60bpm who underwent coronary CT angiography were retrospectively collected. Either bisoprolol or atenolol was orally administered the night before to 166 patients (beta group), and no additional medication was administered to the other 148 patients (control group). When the heart rate was >60bpm on arrival, a β-blocker or verapamil was orally administered at the discretion of the physician. Although the baseline heart rate was not significantly different between the groups, the β-blocker treatment the night before significantly reduced the heart rate compared to control group upon arrival at the hospital and at the time of angiography. The rate of achievement of a heart rate ≤60bpm on arrival at the hospital was significantly higher in the beta group, and even after the additional treatment. ConclusionsBedtime administration of a long-acting β-blocker the night before coronary CT angiography is an effective option to achieve the target heart rate at the time of examination.

Sex-based prognostic implications of nonobstructive coronary artery disease: results from the international multicenter CONFIRM study.

To determine the clinical outcomes of women and men with nonobstructive coronary artery disease ( CAD coronary artery disease ) with coronary computed tomographic (CT) angiography data in patients who were similar in terms of CAD coronary artery disease risk factors, angina typicality, and CAD coronary artery disease extent and distribution. Institutional review board approval was obtained for all participating sites, with either informed consent or waiver of informed consent. In a prospective international multicenter cohort study of 27 125 patients undergoing coronary CT angiography at 12 centers, 18 158 patients with no CAD coronary artery disease or nonobstructive (<50% stenosis) CAD coronary artery disease were examined. Men and women were propensity matched for age, CAD coronary artery disease risk factors, angina typicality, and CAD coronary artery disease extent and distribution, which resulted in a final cohort of 11 462 subjects. Nonobstructive CAD coronary artery disease presence and extent were related to incident major adverse cardiovascular events ( MACE major adverse cardiovascular events ), which were inclusive of death and myocardial infarction and were estimated by using multivariable Cox proportional hazards models. At a mean follow-up ± standard deviation of 2.3 years ± 1.1, MACE major adverse cardiovascular events occurred in 164 patients (0.6% annual event rate). After matching, women and men experienced identical annualized rates of myocardial infarction (0.2% vs 0.2%, P = .72), death (0.5% vs 0.5%, P = .98), and MACE major adverse cardiovascular events (0.6% vs 0.6%, P = .94). In multivariable analysis, nonobstructive CAD coronary artery disease was associated with similarly increased MACE major adverse cardiovascular events for both women (hazard ratio: 1.96 [95% confidence interval { CI confidence interval }: 1.17, 3.28], P = .01) and men (hazard ratio: 1.77 [95% CI confidence interval : 1.07, 2.93], P = .03). When matched for age, CAD coronary artery disease risk factors, angina typicality, and nonobstructive CAD coronary artery disease extent, women and men experience comparable rates of incident mortality and myocardial infarction.

Cost-Effectiveness of Follow-Up of Pulmonary Nodules Incidentally Detected on Cardiac Computed Tomographic Angiography in Patients With Suspected Coronary Artery Disease

Pulmonary nodules (PNs) are often detected incidentally during coronary computed tomographic (CT) angiography, which is increasingly being used to evaluate patients with chest pain symptoms. However, the efficiency of following up on incidentally detected PN is unknown. We determined demographic and clinical characteristics of stable symptomatic patients referred for coronary CT angiography in whom incidentally detected PNs warranted follow-up. A validated lung cancer simulation model was populated with data from these patients, and clinical and economic consequences of follow-up per Fleischner guidelines versus no follow-up were simulated. Of the 3665 patients referred for coronary CT angiography, 591 (16%) had PNs requiring follow-up. The mean age of patients with PNs was 59±10 years; 66% were male; 67% had ever smoked; and 21% had obstructive coronary artery disease. The projected overall lung cancer incidence was 5.8% in these patients, but the majority died of coronary artery disease (38%) and other causes (57%). Follow-up of PNs was associated with a 4.6% relative reduction in cumulative lung cancer mortality (absolute mortality: follow-up, 4.33% versus non-follow-up, 4.54%), more downstream testing (follow-up, 2.34 CTs per patient versus non-follow-up, 1.01 CTs per patient), and an average increase in quality-adjusted life of 7 days. Costs per quality-adjusted life-year gained were $154 700 to follow up the entire cohort and $129 800 per quality-adjusted life-year when only smokers were included. Follow-up of PNs incidentally detected in patients undergoing coronary CT angiography for chest pain evaluation is associated with a small reduction in lung cancer mortality. However, significant downstream testing contributes to limited efficiency, as demonstrated by a high cost per quality-adjusted life-year, especially in nonsmokers.

Left ventricular function and volume with coronary CT angiography improves risk stratification and identification of patients at risk for incident mortality: results from 7758 patients in the prospective multinational CONFIRM observational cohort study.

To assess whether gradations of left ventricular (LV) ejection fraction (LVEF) and volumes measured with coronary computed tomography (CT) would augment risk stratification and discrimination for incident mortality. This study was approved by the institutional review board, and informed consent was obtained when required. Subjects without known coronary artery disease (CAD) who underwent cardiac CT angiography with quantitative LV measurements were categorized according to LVEF (≥ 55%, 45%-54.9%, 35%-44.9%, or <35%). LV end-systolic volume (LVESV) and LV end-diastolic volume (LVEDV) were classified as normal (≥ 90 mL) or abnormal (≥ 200 mL). CAD extent and severity was categorized as none, nonobstructive, obstructive (≥ 50%), one-vessel, two-vessel, and three-vessel or left main disease. LVEF and volumes were assessed for risk prediction and discrimination of future mortality by using Cox hazards model and receiver operating characteristic curve analysis, respectively. During a follow-up of 2.0 years ± 0.9, 7758 patients (mean age, 58.5 years ± 13.0; 4220 male patients [54.4%]) were studied. At multivariable analysis, worsening LVEF was independently associated with mortality for moderately (hazard ratio = 3.14, P < .001) and severely (hazard ratio = 5.19, P < .001) abnormal ejection fraction. LVEF demonstrated improved discrimination for mortality (Az = 0.816) when compared with CAD risk factors alone (Az = 0.781) or CAD risk factors plus extent and severity. At multivariable analysis of a subgroup of 3706 individuals, abnormal LVEDV (hazard ratio = 4.02) and LVESV (hazard ratio = 6.46) helped predict mortality (P < .001). Similarly, LVESV and LVEDV demonstrated improved discrimination when compared with CAD risk factors or CAD extent and severity (P < .05). LV dysfunction and volumes measured with cardiac CT angiography augment risk prediction and discrimination for future mortality.

Coronary artery plaque volume and obesity in patients with diabetes: the factor-64 study.

To determine the relationship between coronary plaque detected with coronary computed tomographic (CT) angiography and clinical parameters and cardiovascular risk factors in asymptomatic patients with diabetes. All patients signed institutional review board-approved informed consent forms before enrollment. Two hundred twenty-four asymptomatic diabetic patients (121 men; mean patient age, 61.8 years; mean duration of diabetes, 10.4 years) underwent coronary CT angiography. Total coronary artery wall volume in all three vessels was measured by using semiautomated software. The coronary plaque volume index (PVI) was determined by dividing the wall volume by the coronary length. The relationship between the PVI and cardiovascular risk factors was determined with multivariable analysis. The mean PVI (±standard deviation) was 11.2 mm(2) ± 2.7. The mean coronary artery calcium (CAC) score (determined with the Agatston method) was 382; 67% of total plaque was noncalcified. The PVI was related to age (standardized β = 0.32, P < .001), male sex (standardized β = 0.36, P < .001), body mass index (BMI) (standardized β = 0.26, P < .001), and duration of diabetes (standardized β = 0.14, P = .03). A greater percentage of soft plaque was present in younger individuals with a shorter disease duration (P = .02). The soft plaque percentage was directly related to BMI (P = .002). Patients with discrepancies between CAC score and PVI rank quartiles had a higher percentage of soft and fibrous plaque (18.7% ± 3.3 vs 17.4% ± 3.5 [P = .008] and 52.2% ± 7.2 vs 47.2% ± 8.8 [P < .0001], respectively). In asymptomatic diabetic patients, BMI was the primary modifiable risk factor that was associated with total and soft coronary plaque as assessed with coronary CT angiography.

Potential Predictors of Side-Branch Occlusion in Bifurcation Lesions after Percutaneous Coronary Intervention: A Coronary CT Angiography Study

To identify potential predictors of side-branch occlusion after main-vessel (artery) stent implantation in bifurcation lesions by using coronary computed tomography (CT) angiography. This retrospective study was approved by the institutional review board; informed consent was waived. Sixty-five patients with de novo bifurcation lesions underwent coronary CT angiography before percutaneous coronary intervention. By defining side-branch occlusion as Thrombolysis in Myocardial Infarction flow grade 2 or lower, coronary CT angiography plaque characteristics associated with side-branch occlusion (ie, plaque morphology and composition) were analyzed. A multiple logistic regression analysis was undertaken to determine independent potential predictors of side-branch occlusion. Of 65 patients enrolled, 12 patients (18%) had side-branch occlusion after main-vessel stent implantation. Patients with side-branch occlusion had larger mean plaque thickness in the side-branch side of the proximal main vessel (2.29 mm ± 1.87 [standard deviation] vs 1.29 mm ± 1.43, P = .043), larger plaque thickness in the noncarinal side of the side branch (1.43 mm ± 1.18 vs 0.51 mm ± 0.65, P < .001), smaller side-branch lumen diameter (1.24 mm ± 0.74 vs 1.87 mm ± 0.71, P = .007), and higher diameter stenosis (50.9% ± 24.0 vs 25.5% ± 25.3, P = .002) compared with those without side-branch occlusion. The cutoff value of proximal main vessel plaque thickness was 2.7 mm (area under the curve [AUC], 0.67; 95% confidence interval [CI]: 0.48, 0.86) and of side-branch-diameter stenosis was 40% (AUC, 0.79; 95% CI: 0.67, 0.92). Lesions with plaque thickness in proximal main vessel greater than 2.7 mm and side-branch-diameter stenosis greater than 40% were associated with a 5.6-fold and 6.2-fold, respectively, increased risk of side-branch occlusion. Potential coronary CT angiography predictors of side-branch occlusion in bifurcation lesions are plaque thickness in the side-branch side of the proximal main vessel, plaque thickness in the noncarinal side of the side branch, side-branch lumen diameter, and side-branch-diameter stenosis. These potential predictors might guide operators planning the optimal strategy for treating bifurcation lesions.

Collateral Vessel Opacification with CT in Patients with Coronary Total Occlusion and Its Relationship with Downstream Myocardial Infarction

To assess the correlation between the filling pattern of distal coronary vessels in patients with chronic total occlusion (CTO) observed at coronary computed tomographic (CT) angiography and the extent of downstream myocardial infarction (MI). All patients gave written informed consent, and the institutional review board approved the study protocol. A total of 97 patients (mean age, 68.5 years ± 11.5 [standard deviation]; age range, 38-87 years; 77 men, 20 women) with 106 CTOs were prospectively enrolled. Distal filling of the epicardial segment was semiquantitatively classified by using a four-point scale according to patterns at coronary CT angiography (0 = absence of distal filling; 1 = partial distal filling, with a length less than one-third of the segment; 2 = partial distal filling, with a length between one-third and two-thirds of the segment; 3 = complete or partial distal filling, with a length longer than two-thirds of the segment). A coronary CT angiography score of 3 was considered indicative of well-developed collaterals. Downstream MI transmurality and wall motion abnormality were verified semiquantitatively with cardiac magnetic resonance imaging. Mann-Whitney U test and t test were used for comparison. Coronary CT angiography revealed three lesions with a score of 0, 21 with a score of 1, 35 with a score of 2, and 47 with a score of 3. The non-MI subgroup was associated with higher collateral grading at CT angiography, whereas the transmural MI subgroup was associated with lower collateral grading (P = .005). When compared with the poorly developed (score 0-2) collaterals group, the well-developed (score 3) collateral group correlated to a lower summed transmurality score (P < .001) and a lower summed regional wall motion abnormality score (P = .029). The presence of well-developed distal collaterals as revealed by coronary CT angiography in patients with CTO lesions correlates with the lower frequency and extent of downstream MI.

Tomografia computerizzata delle coronarie: piccolo vademecum per il nefrologo

La tomografia (TC) coronarica viene utilizzata su larga scala grazie alle sua caratteristiche di migliore risoluzione spazio-temporale. Il valore diagnostico della TC coronarica è andato via via migliorando grazie alla sua evoluzione in TC multistrato; si è, infatti, passati dagli originari 4 strati agli attuali 320 strati, con un netto guadagno in termini di risoluzione e, quindi, di nitidezza delle immagini. Nonostante l'indubbio valore diagnostico e, in parte, anche prognostico, la TC coronarica presenta indicazioni limitate in alcuni specifici campi di applicazione, in virtù dell'elevata prevalenza di artefatti e di falsi positivi determinati dalla presenza di calcificazioni vascolari e/o valvolari. Scopo della presente rassegna è quello di presentare l'evoluzione tecnologica della TC coronarica negli ultimi anni e le sue implicazioni dal punto di vista prognostico. (Cardionephrology)

Diagnostic Accuracy of Coronary CT Angiography

To investigate the diagnostic accuracy of coronary computed tomographic (CT) angiography (CCTA) using filtered back projection (FBP) and sinogram-affirmed iterative reconstruction (SAFIRE) of different strength factors with invasive coronary angiography as the reference standard. Fifty consecutive patients (32 men and 18 women) prospectively underwent electrocardiogram-triggered CCTA on a dual-source CT system. The acquisition window was set depending on the heart rate (HR): HR of less than 60 beats per minute (bpm) at the 70% RR interval, 61 to 80 bpm at 30% to 80% RR interval, and greater than 80 bpm at 30% to 50% RR interval; 100 kV and 359 to 377 mA s for patients with a body mass index of less than 24 kg/m, and 410 to 438 mA s at 120 kV for patients with a body mass index of 24 kg/m or greater. Image data were reconstructed using both FBP and SAFIRE. Sinogram-affirmed iterative reconstruction series were reconstructed using 3 different strength factors. Two blinded observers independently assessed the image quality and image impression of each coronary segment using a 4-point scale (1, non-diagnostic; and 4, excellent). Image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured. Filtered back projection and all SAFIRE series were independently evaluated for coronary artery stenosis (>50%), and their diagnostic accuracy was compared with invasive coronary angiography. Statistically significant increases in SNR and CNR were obtained when higher strength factors were used. The highest SNR and CNR were found with the highest SAFIRE strength factor of 5; however, this strength also resulted in a more unfamiliar, "plasticlike" image appearance. Imaging quality scores of FBP and different SAFIRE strengths were 3.37 ± 0.49, 3.41 ± 0.47, 3.52 ± 0.30, and 3.48 ± 0.35, respectively (P < 0.001). The diagnostic accuracies were 92.91%, 93.76%, 95.28%, and 94.94% on per-segment level, respectively (P = 0.993). A tendency toward higher diagnostic performance was observed with SAFIRE strength factor 3 on per-segment analysis, albeit without reaching statistical significance. The effective radiation dose equivalent was 5.7 ± 1.6 mSv. Sinogram-affirmed iterative reconstruction provides significant improvements in image noise, SNR, and CNR compared with FBP, which are progressive with increasing SAFIRE strength factors. Sinogram-affirmed iterative reconstruction strength factor 3 or 5 is recommended for use with CCTA.

Clinical Implications of the Coronary Artery Calcium Score in Japanese Patients

Coronary artery calcification (CAC) is a well-established surrogate marker of the total burden of coronary atherosclerosis. The CAC score, as measured on coronary computed tomography (CT), is associated with the prevalence of coronary artery disease (CAD) as well as cardiovascular morbidity and mortality. The CAC score is used to reclassify coronary risks in asymptomatic individuals with intermediate risks. However, there are few clinical data regarding the usefulness of the CAC score for identifying high-risk Japanese patients. In this review article, we describe our previous studies of the prognostic value of the CAC score in patients with proven or suspected CAD. In addition, we reanalyzed our previous data for 723 patients with suspected CAD and found both all-cause and cardiovascular disease mortality to be significantly higher among the patients with a CAC score of ≥100 than among those with a CAC score of ＜100. Several studies from Japan have also shown that the CAC score is associated with the prevalence of obstructive CAD, as demonstrated on invasive coronary angiography or stress myocardial perfusion imaging. Furthermore, the CAC score provides useful information for performing coronary CT angiography, as asymptomatic patients without CAC are expected to have favorable outcomes. In contrast, the diagnostic accuracy is decreased in patients with a high CAC score (＞400 or 600). In conclusion, the CAC score may have useful clinical applications in symptomatic and asymptomatic Japanese individuals. However, further studies are required to evaluate the prognostic value of this parameter for predicting cardiovascular morbidity and mortality in population-based analyses of asymptomatic Japanese subjects.

Takayasu Arteritis: Assessment of Coronary Arterial Abnormalities with 128-Section Dual-Source CT Angiography of the Coronary Arteries and Aorta

Purpose To evaluate coronary arterial lesions and to assess their correlation with clinical findings in patients with Takayasu arteritis (TA) by using coronary computed tomographic (CT) angiography. Materials and Methods This retrospective study was approved by the hospital internal review board, and informed consent was waived. A total of 111 consecutive patients with TA (97 female, 14 male; mean age, 44 years ± 13.8 [standard deviation]; age range, 14–74 years) underwent CT angiography of the coronary arteries and aorta with 128-section dual-source CT. CT angiographic, clinical, and laboratory findings of each patient were retrospectively reviewed. Statistical differences between coronary CT angiographic findings and clinical parameters were examined with univariate analysis. Results Of 111 patients, 32 (28.8%) had cardiac symptoms and the remaining 79 (71.2%) had no cardiac symptoms. Fifty-nine patients (53.2%) had coronary arterial lesions at coronary CT angiography. Three main radiologic features were detected: coronary ostial stenosis (n = 31, 28.0%), nonostial coronary arterial stenosis (n = 41, 36.9%), and coronary aneurysm (n = 9, 8.1%). Coronary artery ostial or luminal stenosis of 50% or more or coronary aneurysms were observed in 26 (23.4%) patients with TA. Patients with coronary arterial abnormalities at coronary CT angiography had higher incidences of hypertension (P = .02), were older at the time of CT (P = .01), and had longer duration of TA (P = .02) than those without coronary artery abnormalities. The presence of cardiac symptoms, disease activity, and other comorbidities was not associated with differences in coronary artery involvement. Conclusion In patients with TA, there is a high prevalence of coronary arterial abnormalities at coronary CT angiography, regardless of disease activity or symptoms. Thus, coronary CT angiography may add information on coronary artery lesions in patients with TA. © RSNA, 2013

Takayasu Arteritis: Assessment of Coronary Arterial Abnormalities with 128-Section Dual-Source CT Angiography of the Coronary Arteries and Aorta

To evaluate coronary arterial lesions and to assess their correlation with clinical findings in patients with Takayasu arteritis (TA) by using coronary computed tomographic (CT) angiography. This retrospective study was approved by the hospital internal review board, and informed consent was waived. A total of 111 consecutive patients with TA (97 female, 14 male; mean age, 44 years ± 13.8 [standard deviation]; age range, 14-74 years) underwent CT angiography of the coronary arteries and aorta with 128-section dual-source CT. CT angiographic, clinical, and laboratory findings of each patient were retrospectively reviewed. Statistical differences between coronary CT angiographic findings and clinical parameters were examined with univariate analysis. Of 111 patients, 32 (28.8%) had cardiac symptoms and the remaining 79 (71.2%) had no cardiac symptoms. Fifty-nine patients (53.2%) had coronary arterial lesions at coronary CT angiography. Three main radiologic features were detected: coronary ostial stenosis (n = 31, 28.0%), nonostial coronary arterial stenosis (n = 41, 36.9%), and coronary aneurysm (n = 9, 8.1%). Coronary artery ostial or luminal stenosis of 50% or more or coronary aneurysms were observed in 26 (23.4%) patients with TA. Patients with coronary arterial abnormalities at coronary CT angiography had higher incidences of hypertension (P = .02), were older at the time of CT (P = .01), and had longer duration of TA (P = .02) than those without coronary artery abnormalities. The presence of cardiac symptoms, disease activity, and other comorbidities was not associated with differences in coronary artery involvement. In patients with TA, there is a high prevalence of coronary arterial abnormalities at coronary CT angiography, regardless of disease activity or symptoms. Thus, coronary CT angiography may add information on coronary artery lesions in patients with TA.

Coronary Stenosis: Morphologic Index Characterized by Using CT Angiography Correlates with Fractional Flow Reserve and Is Associated with Hemodynamic Status

To study the diagnostic performance of the ratio of lesion length (LL) to the fourth power of minimal lumen diameter (MLD) (MLD(4)) at coronary computed tomographic (CT) angiography for differentiating between hemodynamically significant and nonsignificant lesions, with correlation with fractional flow reserve (FFR). This retrospective study had institutional review board approval, and the need to obtain informed consent was waived. Sixty-one patients (mean age, 65.3 years ± 8.8 [standard deviation]; range, 43-82 years; 43 men and 18 women; P = .019 for age) who underwent both coronary CT angiography and FFR measurement at conventional coronary angiography within 2 weeks were retrospectively included in this study. LL/MLD(4) ratio, along with other parameters, including minimal luminal area (MLA), stenosis diameter, stenosis area, plaque burden, remodeling index, and Agatston score of lesions, were recorded. Lesions with FFRs of less than 0.8 were considered to be functionally significant. Univariate and multivariate statistical tests were performed to identify variables associated with hemodynamically significant lesions. Sixty-one patients with 85 lesions were ultimately included for analysis. LL, stenosis diameter, stenosis area, and plaque burden were longer or larger in the group with FFRs of less than 0.8 (P < .001 for all), while smaller MLA and MLD were also noted (P < .001). Mean LL/MLD(4) ratio was significantly larger in the group with FFRs of less than 0.8 than in the group with FFRs of 0.8 or greater (9.7 ± 7.5 vs 3.1 ± 3.6, P < .001). Rest myocardial perfusion defect was recorded in five lesions with FFRs of less than 0.8 (P = .006). LL/MLD(4) ratio proved at multivariate analysis to be the only independent predictor of hemodynamically significant stenosis (odds ratio = 1.44; P = .043). When 3.86 was used as the cutoff value for LL/MLD(4) ratio, the sensitivity and specificity for diagnosing hemodynamically significant lesions were 82.9% (29 of 35) and 82% (41 of 50), respectively. The LL/MLD(4) ratio, as characterized by using coronary CT angiography, correlates inversely with FFR measurements and is associated with the hemodynamic status of coronary stenoses. Online supplemental material is available for this article.

Coronary Stenosis: Morphologic Index Characterized by Using CT Angiography Correlates with Fractional Flow Reserve and Is Associated with Hemodynamic Status

Purpose To study the diagnostic performance of the ratio of lesion length (LL) to the fourth power of minimal lumen diameter (MLD) (MLD4) at coronary computed tomographic (CT) angiography for differentiating between hemodynamically significant and nonsignificant lesions, with correlation with fractional flow reserve (FFR). Materials and Methods This retrospective study had institutional review board approval, and the need to obtain informed consent was waived. Sixty-one patients (mean age, 65.3 years ± 8.8 [standard deviation]; range, 43–82 years; 43 men and 18 women; P = .019 for age) who underwent both coronary CT angiography and FFR measurement at conventional coronary angiography within 2 weeks were retrospectively included in this study. LL/MLD4 ratio, along with other parameters, including minimal luminal area (MLA), stenosis diameter, stenosis area, plaque burden, remodeling index, and Agatston score of lesions, were recorded. Lesions with FFRs of less than 0.8 were considered to be functionally significant. Univariate and multivariate statistical tests were performed to identify variables associated with hemodynamically significant lesions. Results Sixty-one patients with 85 lesions were ultimately included for analysis. LL, stenosis diameter, stenosis area, and plaque burden were longer or larger in the group with FFRs of less than 0.8 (P < .001 for all), while smaller MLA and MLD were also noted (P < .001). Mean LL/MLD4 ratio was significantly larger in the group with FFRs of less than 0.8 than in the group with FFRs of 0.8 or greater (9.7 ± 7.5 vs 3.1 ± 3.6, P < .001). Rest myocardial perfusion defect was recorded in five lesions with FFRs of less than 0.8 (P = .006). LL/MLD4 ratio proved at multivariate analysis to be the only independent predictor of hemodynamically significant stenosis (odds ratio = 1.44; P = .043). When 3.86 was used as the cutoff value for LL/MLD4 ratio, the sensitivity and specificity for diagnosing hemodynamically significant lesions were 82.9% (29 of 35) and 82% (41 of 50), respectively. Conclusion The LL/MLD4 ratio, as characterized by using coronary CT angiography, correlates inversely with FFR measurements and is associated with the hemodynamic status of coronary stenoses. © RSNA, 2013 Online supplemental material is available for this article.

Computed Fractional Flow Reserve (FFTCT) Derived from Coronary CT Angiography

Recent advances in image-based modeling and computational fluid dynamics permit the calculation of coronary artery pressure and flow from typically acquired coronary computed tomography (CT) scans. Computed fractional flow reserve is the ratio of mean coronary artery pressure divided by mean aortic pressure under conditions of simulated maximal coronary hyperemia, thus providing a noninvasive estimate of fractional flow reserve (FFRCT) at every point in the coronary tree. Prospective multicenter clinical trials have shown that computed FFRCT improves diagnostic accuracy and discrimination compared to CT stenosis alone for the diagnosis of hemodynamically significant coronary artery disease (CAD), when compared to invasive FFR as the reference gold standard. This promising new technology provides a combined anatomic and physiologic assessment of CAD in a single noninvasive test that can help select patients for invasive angiography and revascularization or best medical therapy. Further evaluation of the clinical effectiveness and economic implications of noninvasive FFRCT are now being explored.