Abstract
Aim
The study was designed with the aims to evaluate the use of multidetector CT (MDCT) in coronary plaque detection and characterization in diabetic and non-diabetic subjects. Further, to compare the plaque morphology and composition in diabetic and non-diabetic patients in both symptomatic and asymptomatic subgroups.
Methods
We performed CT coronary angiography (CTCA) of 100 patients, out of which 50 had type II diabetes and further subdivided into symptomatic and asymptomatic groups. For every patient, we mapped the disease with different grades of coronary artery disease (CAD), the number of plaques, and histological types of plaques, as well as different atherosclerotic scores were derived to assess the severity and extent of CAD.
Results
The total number of assessable segments was 1410 (96%). The symptomatic diabetic patient had a higher prevalence of significant CAD. Coronary, atherosclerotic, and extent scores showed significant difference in diabetic patients as compared to non-diabetic (p < 0.0181, < 0.0125, < 0.0043) whereas severity score was insignificant (p < 0.0627). There was a significant difference in all the scores in symptomatic diabetic and symptomatic non-diabetic subgroups. Further, no difference was observed in the asymptomatic subgroup. Diabetic patients harbor twice the plaque volume as compared to non-diabetic. Vulnerable plaques were more prevalent in asymptomatic patients with intermediate grade stenosis.
Conclusions
CTCA plays a pivotal role in the risk stratification. Diabetic patients were found have intermediate grade stenosis and higher load of both stable and vulnerable plaques than non-diabetics. Furthermore, the percentage of vulnerable plaque was higher in asymptomatic group as compared to symptomatic patients.
Keywords: Coronary artery plaque characterization, CTCA, Diabetes
Introduction
Type II diabetes mellitus (DM) is a well-known risk factor for coronary atherosclerosis and is associated with 2–4 times increased risk of myocardial infarction (MI) and resulting mortality [1, 2]. The impact of diabetes on cardiovascular disease is further illustrated by the fact that the risk of developing MI in diabetic patients without known heart disease is equivalent to the risk observed in non-diabetic survivors of a prior infarct [3]. The newer-generation CT (computed tomography) scanners enable exquisite imaging of coronary arteries, coronary plaque morphology, and details of atherosclerotic lesions quickly, with minimal patient discomfort or risk [4, 5]. The cross-sectional contrast-enhanced images provide vessel wall assessment allowing accurate assessment of atherosclerotic plaque load, an advantage over conventional angiography [6]. The present study is designed to evaluate the use of CT coronary angiography (CTCA) in plaque detection and characterization, as well as to compare plaque burden, morphology, and composition in diabetic and non-diabetic patients.
Materials and methods
Study design
All 100 patients were selected prospectively and analyzed individually retrospectively by two expert assessors who were unaware of clinical data. Out of 100 patients, 50 were patients with type II DM [7] and 50 were non-diabetics. For all patients, a detailed clinical history of the following risk factors was recorded at the time of examination: systemic hypertension [8], hypercholesterolemia [9], obesity [10], family history of coronary artery disease (CAD) [11], and smoking (previous or current smoker).
Both groups consisted of patients who came to “Advanced Diagnostics & Institute of Imaging” for the screening of CAD and presented with intermediate to high-risk Framingham factors, chronic angina, unstable angina, silent ischemia, or atypical chest pain. Exclusion criteria included allergy to iodinated contrast agents, heavily calcified coronary arteries, atrial fibrillation, presence of stents or bypass grafts, history of MI, cardiac and renal failure, and pregnancy. Both groups were further subdivided into symptomatic and asymptomatic subgroups according to the symptoms of chest pain and dyspnea at the time of scanning. These patients then underwent CTCA after written informed consent.
Patient preparation
All patients with a resting heart rate of > 60 beats/min received 50–100 mg of oral metoprolol 1 h before the scan or 5–20 mg of intravenous metoprolol immediately before the scan unless there was an absolute contraindication.
Protocol
CTCA was performed using a 64-detector-row sensation 64 scanner (Siemens Sensation, Erlangen Germany AG) with commercially available 7890 cardiac reconstruction software (Circulation, Erlangen Germany AG). Contrast-enhanced volume datasets were acquired using 64 × 0.6 mm collimation and 0.6 mm pitch with gantry rotation time of 33 or 37 ms, depending on the patient’s heart rate, and a tube voltage of 120 kV and 600–700 mA s. Approximately, 70 ml of iomeprol (400 mg iodine/ml) was injected at a rate of 5 ml/s in a single-breath-hold via the antecubital vein by using a 18-G intravenous line, depending on the patient’s weight, followed by 30 ml saline. A bolus tracker was placed in the ascending aorta, and a preset threshold of 100 Hounsfield units was used. The computerized electrocardiography (ECG) tracing was recorded simultaneously during acquisition for retrospective reconstruction.
Image reconstruction
Volumetric data were acquired throughout the cardiac cycle, and retrospective reference data for image reconstruction from specific parts of the cardiac cycle, typically late diastole, was used. All images were reconstructed with a medium smooth reconstruction kernel. Axial images, maximum intensity projection (MIP) images, and multi-planar reformatted (MPR) images were used. Oblique MPR images were used to confirm the pathologic findings in the long and short axes of the vessels.
Image analysis
The sites of greatest luminal narrowing were assessed in cross-sectional images for the presence of atherosclerotic plaques. With the contrast-filled lumen as the calibration standard, the minimum lumen diameter during diastole, as measured from orthogonal projections, was recorded. Coronary atherosclerotic plaques were visually typed as non-calcified and/or calcified. Analysis of plaque character and number in all three major vessels and their branches was performed using the cardiac reconstruction software (Circulation Siemens Erlangen Germany AG), which detects plaques and the number and volume of each plaque. Using quantitative coronary angiography (QCA), computerized quantitative analysis of the entire coronary tree, 15 segments were performed (Fig. 1) [12]. The quantitative results were visually assessed by two experienced readers. Color coding was used to define the composition of a plaque. Dark green was assigned for a plaque with an attenuation of 0–30 HU; green, 31–90 HU; and pink, > 90; and orange indicated contrast in the lumen of the vessel [13, 14]. The composition of the plaque causing maximum narrowing was calculated as the average of the composition of the plaque causing maximum lumen narrowing, as well as of the immediate distal and proximal near normal/ normal lumen. These plaques were then typed according to their composition and duration of the CAD/type II DM.
Fig. 1.
The 15 coronary segments according to the American Heart Association (AHA) reporting system
The following information were recorded for all patients:
Number of assessable segments.
All 15 segments were then graded as grade 0, < 25% stenosis; grade 1, < 50% stenosis; grade 2, < 75% stenosis; grade3, 76–95% stenosis; grade 4, occlusion defined as a > 95% stenosis with a severely reduced or no antegrade flow, according to its most severe diameter reduction.
The number of plaques in each vessel, plaque volume, length, remodeling, and nature of plaque.
Plaques were typed as IV (fatty), Va (fibro-fatty), Vb (calcified), Vc (fibrous with little lipid or calcium), VI (ulcerated, hematoma, thrombus), VII (fibro-calcific), and VIII (fibrous). Plaques of types IV, Va, and VI were considered as vulnerable plaque in this study.
Four scores were derived to describe coronary atherosclerosis as described by Ledru et al. [15]. The “coronary score” is defined as the number of coronary arteries exhibiting stenosis with more than 75% diameter reduction (grade 3 or 4). Greater than 50% stenosis of the left main coronary artery was considered two-vessel CAD. The “extent score” was the number of segments exhibiting lesions equal to or greater than grade 1, adjusted to 15 coronary segments. The “severity score” was calculated as the average grade of the diseased coronary segments (i.e., grade 1 or higher). This score measures the average severity of atherosclerosis per segment, normalized to the total number of the assessable segments per patient. The “atherosclerotic score” was calculated as the average severity of all analyzable segments. This score measures the average grade of atherosclerosis normalized to affected segments per patient. Atherosclerosis involving the left main (LM), the proximal left anterior descending (LAD) and circumflex arteries (LCx), and the first three segments of the right coronary artery (RCA) was considered proximal coronary atherosclerosis (segments 1, 2, 3, 5, 6, 7, 9, 11, 12, 13), whereas atherosclerosis involving the other coronary segments was considered distal coronary atherosclerosis (segments 4, 8, 10, 14, 15).
Data obtained for each group were statistically analyzed to determine differences in disease pattern among the comparison groups. Data were analyzed by using the Analyze-it software, with the p value less than 0.05 considered statistically significant. Student’s t test and chi-square test were performed to determine the statistical significance of the results.
Results
All patients underwent CTCA without complications. The clinical features and risk characteristics of the patients are shown in Table 1. All groups had similar baseline characteristics except the sex ratio.
Table 1.
Clinical features and risk factors of study groups
| Risk factors | DM | NDM | ADM (n = 11) | SDM (n = 39) | ANDM (n = 13) | SNDM (n = 37) | p value for DM/NDM | p value for ADM/ANDM | p value for SDM/SNDM |
|---|---|---|---|---|---|---|---|---|---|
| Age in years, mean (SD) | 56.8 (11.3) | 54.2 (13) | 50 (12.5) | 58.7 (12.4) | 49.1 (12.3) | 56 (12.4) | < 0.29 | < 0.47 | < 0.49 |
| Male (%) | 42 (84) | 26 (52) | 81.80 | 84.60 | 30.70 | 59.40 | < 0.001 | < 0.012 | < 0.014 |
| Hypertension (%) | 30 (60) | 28 (56) | 54.5% (6) | 61.53% (24) | 53.84% (7) | 56.75% (21) | < 0.685 | < 0.973 | < 0.672 |
| Family history of DM type II or CAD (6%) | 14 (28) | 11 (22) | 54.54% (6) | 20.51% (8) | 23.07% (3) | 21.62% (8) | < 0.488 | < 0.113 | < 0.906 |
| Abnormal lipid profile (%) | 17 (34) | 6 (12) | 36.36% (4) | 33.33% (13) | 15.38% (2) | 10.81% (4) | < 0.009 | < 0.237 | < 0.019 |
| Smoking (%) | 1 (2) | 0 (0) | 0 | 2.56% (1) | 0 | 0 | |||
| Obesity (%) | 12 (24) | 16 (32) | 45.45% (5) | 18% (7) | 61.5% (8) | 21.6% (8) | < 0.373 | < 0.431 | < 0.688 |
Data are represented as mean (standard deviation) or number (percentage)
DM diabetic, NDM non-diabetic, ADM asymptomatic diabetic patients, SDM symptomatic diabetic patients, ANDM asymptomatic non-diabetic patients, SNDM symptomatic non-diabetic patients
CTCA findings
Total numbers of assessable segments were 1410 (94%) and those of non-assessable segments were 90 (6%). The non-assessability was owing to highly calcified segments, tachyarrhythmia, and small vessel caliber in distal segments.
Patients with coronary artery disease more than grade II are shown in Table 2.
Table 2.
Coronary atherosclerotic disease prevalence in four categories
| Patients with CAD | Percentage prevalence | Patients with CAD | Percentage prevalence | ||
|---|---|---|---|---|---|
| Diabetic patients (n = 50) | 38 | 76% | Asymptomatic diabetic patients | 4 | 36% |
| Symptomatic diabetics patients | 34 | 87% | |||
| Non-diabetic patients (n = 50) | 31 | 62% | Asymptomatic non-diabetic patients | 6 | 46% |
| Symptomatic non-diabetic patients | 25 | 67% |
Chi-square value for diabetic and non-diabetic was 2.338, p = 0.126 (NS). Chi-square value for asymptomatic diabetic and asymptomatic non-diabetic was 0.413, p = 0.520 (NS). Chi-square value for symptomatic diabetic and symptomatic non-diabetic was 4.265, p = 0.039. Degree of freedom = 1
Mostly, plaques were located in proximal LAD (n = 33), mid-LAD (n = 29), proximal RCA (n = 23), proximal LCx (n = 20), and mid-RCA (n = 16).
Only 1 asymptomatic diabetic patient had distal atherosclerosis with no associated proximal atherosclerosis. Isolated proximal atherosclerosis was seen in 36 symptomatic diabetic patients and 10 patients had distal atherosclerosis in association with proximal. Twenty-four symptomatic non-diabetic patients had isolated proximal atherosclerosis and 7 patients had associated distal atherosclerosis. Diabetic patients have the highest prevalence distal atherosclerosis along with proximal as compared to comparison cohort (Fig. 2).
Fig. 2.
Line graph representing the involvement of various segments with CAD. Data are presented as number
Coronary atherosclerotic scores
As shown in Table 3, the “coronary score,” “extent score,” “atherosclerotic score,” and occlusion rate were significantly different between the symptomatic non-diabetic patients and symptomatic diabetic patients. In contrast, there was no significant difference in the scores between patients with asymptomatic diabetes and the asymptomatic non-diabetic patients.
Table 3.
Coronary atherosclerotic scores
| DM | NDM | ADM (n = 11) | SDM (n = 39) | ANDM (n = 13) | SNDM (n = 37) | p value for DM/NDM | p value for ADM/ANDM | p value for SDM/SNDM | |
|---|---|---|---|---|---|---|---|---|---|
| Mean coronary score (SD) | 1.160 (1.113) | 0.680 (0.868) | 0.091 (0.302) | 1.462 (1.072) | 0.231 (0.439) | 0.838 (0.928) | 0.0181* | 0.3817IS | 0.0084** |
| Mean atherosclerotic score (SD) | 0.527 (0.440) | 0.331 (0.321) | 0.133 (0.157) | 0.639 (0.430) | 0.151 (0.164) | 0.395 (0.340) | 0.0125* | 0.787IS | 0.0078** |
| Mean extent score (SD) | 3.660 (2.479) | 2.280 (2.232) | 1.636 (1.629) | 4.231 (2.389) | 1.308 (1.182) | 2.622 (2.419) | 0.0043** | 0.5740IS | 0.0047** |
| Mean severity score (SD) | 1.796 (0.858) | 1.432 (1.064) | 0.787 (0.666) | 2.801 (0.674) | 0.954 (0.930) | 1.599 (1.069) | 0.0627IS | 0.624IS | 0.00001** |
Data are represented as mean (standard deviation) or number (percentage)
IS insignificant
*Significant at 5% significance level
**Significant at 1% significance level
Patients with diabetes had higher “coronary score,” resulting in the significantly higher prevalence of multi-vessel disease than in non-diabetic patients (p = 0.0181) (Figs. 3a, b and 4).
Fig. 3.
Multi-vessel involvement in a symptomatic diabetic patient with a higher coronary score. a High-grade stenosis of LAD. b High-grade stenosis of RCA
Fig. 4.
Asymptomatic diabetic patient with moderate grade stenosis of proximal RCA and low coronary score
Statistical significance of coronary atherosclerotic scores
To determine the differences in the extent of atherosclerosis between diabetic and non-diabetic patients, the means were calculated for coronary, extent, severity, and atherosclerotic scores (Table 3). These scores, except for the severity score, were significantly different between the diabetic and non-diabetic groups and highlighted the increased coronary atherosclerosis in diabetics as compared to non-diabetics. Furthermore, symptomatic diabetic and symptomatic non-diabetic patients showed significant differences for all scores. However, there was no significant difference observed in the scores in the asymptomatic patients.
Diabetic patients had a lower number of normal and higher number of segments with grade 1, grade 2, and grade 3 diseases. Moreover, the complete occlusion was less common in the diabetic population than in the non-diabetic population. Interestingly, in the subgroup, asymptomatic diabetics had more normal segments than the asymptomatic non-diabetics. Symptomatic diabetics also had less normal segments than symptomatic non-diabetics. The number of segments with grade 1, 2, and 3 diseases was more prevalent in asymptomatic diabetics and symptomatic diabetics than their respective comparison groups.
The numbers of segments with grade 4 disease were more prevalent in symptomatic non-diabetics than in the symptomatic diabetic group and in the asymptomatic non-diabetics than in the asymptomatic diabetics. The left main disease was identified in 2% of non-diabetic patients and 2% of patients with diabetes.
CT plaque characteristics and composition
The total plaque volume was determined by adding the total volume of all plaques in 100 patients and was 24.50 mm3. Out of this, the diabetic patients had a significantly higher plaque load (65%) than the non-diabetic patients (34%) (p = 0.0119; Fig. 5a).
Fig. 5.
a, b Plaque volumes. Data are presented as percentage proportion
The asymptomatic diabetic patients had 4.12% of the total plaque burden, whereas the asymptomatic non-diabetic patients had a significantly lower total load at 3.3% (p = 0.199; Fig. 5b).
Statistically significant differences were also observed in the plaque burden in the symptomatic group (p = 0.0047; Fig. 5b).
The mean plaque volume in asymptomatic diabetics, symptomatic diabetics, asymptomatic non-diabetics, and symptomatic non-diabetics was 0.091, 0.38, 0.062, and 0.20 mm3, respectively, with an upper limit of 0.41, 1.58, 0.31, and 1.55mm3, respectively (Fig. 6a, b).
Fig. 6.
a MIP image of an asymptomatic diabetic patient showing fibrous plaque with less plaque load. b MIP image with color coding of the same patient with fibrous plaque at Q9
The frequency and distribution of different types of plaques in the various subgroups are shown in Table 4.
Table 4.
Plaque characteristics
| Plaque type | Asymptomatic diabetic patients | Symptomatic diabetic patients | Asymptomatic non-diabetic patients | Symptomatic non-diabetic patients |
|---|---|---|---|---|
| Type IV | 2 | 18 | 1 | 11 |
| Type Va | 10 | 69 | 12 | 42 |
| Type Vb | 0 | 20 | 0 | 13 |
| Type Vc | 1 | 9 | 2 | 7 |
| Type VI | 0 | 1 | 0 | 0 |
| Type VII | 0 | 40 | 3 | 19 |
| Type VIII | 2 | 4 | 0 | 2 |
| Total (n = 285) | 15 | 161 | 18 | 91 |
| Percentage | 4.9% | 56.69% | 6.3% | 32.04% |
Data are presented as numbers (percentage).
The diabetic patients had more stable (n = 77) and vulnerable plaques (n = 99) than the non-diabetics (n = 43 and n = 66; Fig. 7), respectively. It was observed that the diabetic patients had a higher volume of both vulnerable and stable plaques than did the non-diabetic patients, potentially placing the former group at a higher risk of acute coronary events.
Fig. 7.
Prevalence of vulnerable and stable plaques in diabetic and non-diabetic groups and four subgroups. Data represented in percentage (%age)
The relative plaque composition of intermediate stenosis (grades I and II) was also determined to assess the risk for acute coronary syndrome (ACS) (Fig. 8). It was found that the plaque composition was variable, with the highest prevalence of type Va 38/95 and 46/91 plaques (40 and 50.5%) causing grade II disease and grade I disease, respectively (Fig. 9).
Fig. 8.
Prevalence of different types of plaques causing grade I and II diseases. Data are presented as percentage
Fig. 9.
Percentage proportion of vulnerable plaques causing intermediate grade stenosis in four subgroups. Data are presented as percentage
Discussion
The present study used multidetector computed tomography (MDCT) for assessing coronary atherosclerosis and showed that 94% of the vessels could be assessed, whereas 6% of the segments were not assessable [16–18]. Diabetic patients were found to have a higher percentage of atherosclerotic plaques than non-diabetic patients in our study [19]. Furthermore, the diabetic group also had a higher prevalence of multi-vessel disease, with a high coronary score of 2 and 3, as compared to the non-diabetics. Similarly, the subgroup of symptomatic diabetics had a significantly higher prevalence of multi-vessel disease. The severity score observed in symptomatic diabetics was higher than that observed in symptomatic non-diabetics. However, it was similar in diabetic and non-diabetic patients and the asymptomatic comparison groups, which implies that the diabetic patients do not necessarily have a higher degree of stenosis than the non-diabetic population. Hence, there may be other associated factors that determine the severity of stenosis of CAD [15, 20].
The extent score, atherosclerosis score, and coronary score revealed statistically significant differences between diabetic and non-diabetic patients, with the symptomatic diabetic cohort showing higher scores than the symptomatic non-diabetics. In contrast to the above observation, no statistically significant difference was observed between the asymptomatic diabetic and non-diabetic groups, which was an unexpected observation. However, an analysis of the study to ascertain the reason for this revealed a significant difference in the sex distribution between the two groups. Another possible reason could be a higher percentage of obese patients in asymptomatic non-diabetic group than in the asymptomatic diabetic group.
In the present study, distal atherosclerosis in association with proximal atherosclerosis was found to be more prevalent in diabetic patients than in non-diabetic patients, and only one asymptomatic diabetic patient with isolated distal atherosclerosis was found [15, 21].
Diabetic patients were found to have more grade I and II (i.e., hemodynamically insignificant) and grade III disease (i.e., hemodynamically significant) than the non-diabetic population. Non-diabetic patients had a higher prevalence of grade IV disease than the diabetic population. These results thus validate diabetes as a risk factor for moderate grade stenosis. Thus, diabetic patients may have a higher incidence of myocardial infarction and sudden death without previous angina pectoris.
The overall plaque load was twofold higher in the diabetic population 16.0954 mm3 (65.7%) than in the non-diabetic population 8.4150 mm3 (34.33%). It was earlier thought that coronary artery calcium has strong predictive value than the assessment of cardiovascular risk factor, but all atherosclerotic plaques do not contain calcium nor the extent of plaques assess the vulnerability and stability of plaques.
Hoffmann et al. [22] also showed a high prevalence of non-calcified plaques, which were found in 100 and 77% in patients with ACS and stable angina, respectively. Calcified plaques were found in 71 and 92% of patients with ACS and stable angina, respectively. Our study reflects the heterogeneity of plaques in both subgroups of the diabetics and non-diabetics. Therefore, the study suggests the noninvasive detection of plaque composition, which can eventually improve the risk stratification of such patients. Our study also adds evidence to the notion that the morphology and composition of coronary atherosclerosis are different in patients with and without diabetes, and as expected, the symptomatic patients have a higher plaque burden than the asymptomatic patients.
In the present study, the incidence and proportion prevalence of vulnerable plaques was higher in diabetic patients than in the comparison group [23]. The diabetic group also had higher number of vulnerable as well as stable plaques compared to the non-diabetic group, resulting in intermediate grade stenosis.
Surprisingly, the asymptomatic population in both the groups also had a higher number of vulnerable plaques, i.e., 80 and 72% in diabetics and non-diabetics, respectively, even though the total plaque burden in asymptomatic group was less than that in the symptomatic group. This further added evidence to the fact that factors other than blood sugar play an important role in the progression and stability of coronary plaques.
Another important observation is that a higher plaque volume does not correlate with the presence of vulnerable plaques. In the present study, the symptomatic group had a higher plaque burden but a lower percentage of vulnerable plaques than the asymptomatic group. It is therefore prudent to evaluate such patients using MDCT, even though these patients do not have significant coronary atherosclerosis [24].
Our study also assessed plaque composition in patients with intermediate grade I and II coronary stenosis and found that 54% of these patients had type IV and Va plaques. Finally, it is of utmost importance to determine plaque morphology in patients with hemodynamically insignificant coronary stenosis to detect culprit lesion, as these patients are prone to subsequent cardiac events.
The study also had potential limitations as well, which are as mentioned below:
The sensitivity, specificity, and accuracy of the detection of stenosis of coronary arteries were not evaluated as conventional coronary angiograms were not done in all the patients; hence, no correlation is made with conventional coronary angiograms.
There might have been patients in which MDCT may have overestimated the plaque volume.
Intravascular ultrasound (IVUS) was not done to have a direct comparison of the plaque composition and morphology obtained on MDCT. Hence, there may be occult under/overestimation of plaque morphology.
Partial volume artifacts due to adjacent plaque calcification and contrast in the lumen might have influenced the attenuation characteristics of the plaque, leading to false high attenuation values.
MDCT might have underestimated the total plaque burden because of limitation in the spatial resolution leading to its inability to evaluate plaque in distal and branch vessels, thus affecting the risk stratification of such patients.
Statistically significant difference in the sex distribution in the asymptomatic group might have an influence on the increased prevalence of the atherosclerosis in this subgroup.
There was no separate identification of subgroup of the patients diagnosed to be having metabolic syndrome which might have resulted in skewed data characteristics.
Conclusions
With the advances in MDCT, improvement in the spatial and temporal resolution has made it possible to detect, quantify, and characterize plaque burden. Higher prevalence of CAD was seen in the diabetic then non-diabetic groups (76 and 62%, respectively), especially in symptomatic subgroup. It was found that type II diabetes is usually associated with intermediate-grade stenosis. Further, the diabetic patients had a higher percentage of both vulnerable and stable plaques than the non-diabetics, thus placing the former group at a higher risk of acute coronary syndrome and future cardiac events. It is further recommended that these high-risk individuals should be thoroughly evaluated using noninvasive coronary angiography to stratify the risk. MDCT can detect the total plaque burden along with plaque composition, and the diabetic patients were found to have a higher volume and number of both stable and vulnerable plaques than non-diabetics. Interestingly, the percentage proportion of vulnerable plaque was higher in the asymptomatic group (80 and 72% in diabetics and non-diabetics, respectively) than in the symptomatic group.
CTCA is one of the most recognized tools to noninvasively detect plaque burden and extent, characterize plaque in different histological types. CTCA has potential to identify lipid-rich plaque. However, plaque characterization using MDCT is still in evolving stage, and with further technical improvements in data acquisition and reconstruction, it can have a significant impact on risk stratification of patients.
Compliance with ethical standards
Ethical approval
Ethical clearance was not required as it is a known procedure and well documented and was not a new methodology.
Conflict of interest
The authors declare that they have no conflict of interest.
Informed consent
Informed consent was obtained from all individual participants included in the study.
Contributor Information
Preeti Gupta, Phone: +919760481515, Email: dr.preetigupta@yahoo.co.in.
Naveen Kumar Agarwal, Phone: +919760336161, Email: drnaveenagarwal@gmail.com.
Atul Kapoor, Phone: +918449633578, Email: blackrose.undefined@gmail.com.
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