ObjectiveTo investigate the diagnostic value of CT-derived fractional flow reserve (CT-FFR) and fat attenuation index (FAI) based on artificial intelligence-assisted diagnostic software in coronary artery stenosis. MethodsA retrospective analysis was conducted on patients clinically suspected of coronary artery syndrome who underwent coronary computed tomography angiography at Guangdong Province Traditional Chinese and Western Medicine Hospital between June 2021 and May 2025. Patients were divided into two groups according to scanning protocols: group A underwent conventional retrospective electrocardiography-gated scanning, while group B used Flash_ChestPlin mode. Invasive coronary angiography data served as the gold standard for diagnosing vascular stenosis (stenosis rate<50% defined as negative group, ≥50% with clinical symptoms as positive group). Radiation dose was compared between the two scanning protocols. The diagnostic efficacy of CT-FFR, pericoronary FAI, and transluminal attenuation gradient (TAG) based on artificial intelligence system for coronary stenosis was analyzed, including sensitivity, specificity, and area under the curve (AUC). ResultsA total of 567 vessels from 189 patients were analyzed, including 105 males, 84 females with a mean age of (62.5±12.3) years and a mean body mass index of (24.21±3.5) kg/m2. There were 112 patients in the group A and 77 patients in the group B. The radiation dose in the group B was significantly lower than that in the group A [69.7 (58.1, 84.1) mGy·cm vs. 420.4 (338.6, 514.2) mGy·cm, P<0.001]. Significant differences in FAI and CT-FFR were observed between negative and positive groups under both scanning protocols (P<0.05), while no significant difference existed in TAG (P>0.05). In the group A, the AUC values for diagnosing stenosis were 0.925 for CT-FFR, 0.610 for FAI, and 0.516 for TAG. Corresponding values in the group B were 0.889, 0.677, and 0.548 respectively, with CT-FFR demonstrating optimal diagnostic performance. ConclusionUnder both conventional scanning and Flash scanning, the artificial intelligence-based CT-FFR demonstrates good diagnostic performance for coronary artery stenosis, and the Flash protocol significantly lowers radiation dose, indicating substantial potential for clinical application.
New functional evaluation methods for coronary artery lesions have received widespread attention at home and abroad. As a new functional evaluation technique, the clinical value of quantitative flow ratio (QFR) in the accuracy and feasibility of diagnosing myocardial ischemia caused by coronary artery stenosis has been confirmed in many clinical trials. Compared with the traditional gold standard fractional flow reserve (FFR) for diagnosing coronary artery stenosis, QFR has the advantages of simple operation, time-saving and low cost. This article reviews the comparison of the diagnostic accuracy of FFR and QFR and the progress of clinical research, aiming to explore whether QFR may replace FFR as a functional evaluation method of coronary artery disease and guide clinical blood circulation reconstruction.
For coronary artery diseases, imaging diagnosis is usually used to guide the treatment. However, it can only reflect the geometric characteristics of the disease but does not determine the hemodynamically significant stenosis. This study was aimed to investigate the relationship between angiographic and functional severity of coronary artery stenosis and to improve the diagnostic value of imaging. 39 patients with 55 stenosis vessels were included in this study. The correlation between FFR and stenosis rate was analyzed with the medical statistical analysis method, and the influence of the position of stenosis and coronary dominant type on the correlation was discussed. By regression analysis, the stenosis rate of left anterior descending artery of right dominant type showed a significant correlation with FFR value (r≈0.79, P < 0.000 1) after grouping with position and the dominant type. Due to the significance of a value of the FFR < 0.80 in determining inducible ischemia, the diagnostic accuracy of myocardial ischemia by the stenosis rate increased from 70.9% to 82.8% after grouping. Sensitivity (from 72.2% to 78.6%) and specificity (from 70.3% to 86.7%) were also significantly improved. This study indicates that the position of stenosis and the coronary dominant type are significant influence factors on the correlation between FFR and stenosis rate. Consideration of these two factors in the diagnosis of myocardial ischemia by imaging will be helpful to improve the effectiveness of diagnosis.
We reported a 59-year-old male with exertional angina pectoris, and the coronary angiography showed multiple vessel lesions. The initial strategy was coronary artery bypass grafting (CABG). The measurement of quantitative flow ration (QFR) before operation indicated that the posterior descending branch (PD) did not need to be treated. The left circumflex branch (LCX) was small, and the QFR of the left anterior descending branch (LAD) and the first diagonal branch (D1) was<0.8. Therefore, the LAD and D1 were re-vascularized. The operation strategy was changed to on-pump CABG through a small incision, and the final strategy was LIMA-D1-LAD (sequential), fractional flow reserve (FFR) of distal LAD and D1 after CABG were>0.8 by computed tomography FFR. SYNTAX scores after CABG were 20 and the functional SYNTAX scores after CABG were 3, indicating a good prognosis.
Coronary artery fractional flow reserve (FFR) is a critical physiological indicator for assessment of impaired blood flow caused by coronary artery stenosis. The wire-based invasive measurement of blood flow pressure gradient across stenosis is the gold standard for clinical measurement of FFR. However, it has the risk of vascular injury and requires the use of vasodilators, increasing the time and overall cost of interventional examination. Coronary imaging is playing an important role in clinical diagnosis of stenotic lesions, evaluation of severity of lesions, and planning of therapies. In recent years, the computation of FFR based on the physiological information of blood flow obtained from routinely collected coronary image data has become a research focus in this field. This technique reduces the cost of physiological assessment of coronary lesions and the use of pressure wires. It is beneficial to strengthen the physiological guidance in interventional therapy. In order to better understand this emerging technique, this paper highlights its implementation principle and diagnostic performance, analyzes practical problems and current challenges in clinical applications, and discusses possible future development.
In order to investigate the application of lattice Boltzmann method (LBM) in the numerical simulation of computed tomography angiography-derived fractional flow reserve (FFRCT), an idealized narrowed tube model and two coronary stenosis arterymodels are studied. Based on the open source code library (Palabos), the relative algorithm program in the development environment (Codeblocks) was improved. Through comparing and analyzing the results of FFRCT which is simulated by LBM and finite element analysis software ANSYS, and the feasibility of the numerical simulation of FFRCT by LBM was verified . The results show that the relative error between the results of LBM and finite element analysis software ANSYS is about 1%, which vertifies the feasibility of simulating the coronary FFRCT by LBM. The simulation of this study provides technical support for developing future FFRCT application software, and lays the foundation for the calculation of clinical FFRCT.
Objective To compare the surgical outcomes between conventional coronary artery bypass grafting (CABG) and minimally invasive direct coronary artery bypass grafting via left small thoracotomy stratified by different levels of non-invasive fractional flow reserve computed tomography (FFR-CT), and to explore the recommended FFR-CT cut-off values for selecting appropriate coronary vessels for grafting in the two surgical procedures. MethodsA retrospective enrollment was conducted on patients who underwent isolated CABG at the Minimally Invasive Cardiac Surgery Center of Beijing Anzhen Hospital from 2022 to 2025, including conventional median sternotomy CABG and minimally invasive CABG. Clinical data comprising preoperative FFR-CT of target vessels, preoperative coronary angiography, intraoperative instantaneous flow of corresponding bypass grafts, peak postoperative troponin level, postoperative graft patency after discharge, and the incidence of major adverse cardiovascular and cerebrovascular event (MACCE) were collected. Patients were divided into two groups according to FFR-CT value: FFR-CT＞0.80 and FFR-CT≤0.80. Intraoperative graft flow was classified into three grades: Grade 1 (flow≤30 mL/min), Grade 2 (30 mL/min＜flow≤60 mL/min), and Grade 3 (flow＞60 mL/min). The differences in intraoperative flow corresponding to different FFR-CT levels were compared between patients undergoing conventional CABG and minimally invasive CABG respectively, and regression analyses were performed separately. Postoperative troponin was also graded into three levels: Grade 1 (troponin I＜2 000 ng/L), Grade 2 (2 000 ng/L≤troponin I＜5 000 ng/L), and Grade 3 (troponin I≥5 000 ng/L). Troponin I levels were compared between the two groups. ResultsA total of 390 patients with 928 target vessels were enrolled, including 207 patients undergoing conventional CABG (542 target vessels; 153 males and 54 females, aged 43-81 years) and 183 patients undergoing minimally invasive CABG (386 target vessels; 144 males and 39 females, aged 46-84 years). For conventional CABG, target vessels with FFR-CT≤0.80 presented better intraoperative graft flow. The regression equation was Q (flow grade)=–3.077FFR3+3.455. FFR-CT＜0.78 was recommended to achieve optimal intraoperative graft flow. For minimally invasive CABG, superior intraoperative graft flow was also observed in target vessels with FFR-CT≤0.80, with the regression equation Q (flow grade)=–24.560FFR2+30.207FFR–6.492, and the recommended cut-off value was FFR-CT＜0.80. For coronary arteries with angiographically moderate stenosis, intraoperative graft flow differed significantly among different FFR-CT subgroups (P＜0.001), with higher flow in the FFR-CT≤0.80 group. Moreover, lower FFR-CT value of target vessels was associated with lower peak postoperative troponin I level. ConclusionFFR-CT serves as a reliable reference indicator for target vessel selection in conventional CABG and left small thoracotomy minimally invasive CABG, especially for coronary lesions with angiographically moderate stenosis. In addition, FFR-CT has certain predictive value for postoperative surgical efficacy.
