Diagnostic aspects of multi-detector CT in detection of coronary arteries stenotic lesions diseases versus interventional Diagnostic Angiography

INTRODUCTION

The gold standard for anatomical assessment of coronary artery disease is invasive coronary angiography (ICA). New progress in non-invasive coronary computed tomographic angiography (CCTA) technology, & allow for anatomical examination of coronary arteries without the need for invasive treatments. As the use of CCTA for clinical & research purposes grows.¹

it's critical to know link between parameters produced from CCTA as well as those derived from ICA. Prior research has only looked at small groups of studied case. ²

FFR is an invasive physiologic indicator used to determine presence of ischemia-producing coronary stenosis. ³

Ischemic disease IIID, also known as Coronary Artery Disease CAD, is at the top of the list of the world's most dangerous diseases. It is caused by a buildup of fatty deposits on the artery wall, which is frequently ascribed to lifestyle choices or other high-risk illnesses such as high blood pressure or diabetes. It is responsible for approximately millions of fatalities each year. Studied case's arteries narrow, preventing blood & oxygen flow to the heart & potentially leading to a catastrophic heart attack, making this illness lethal. As a result, several modalities must be used to evaluate CAD, one of which is Coronary CT angiography. Moreover to be Coronary CT angiography has emerged like gold _standard for identification of coronary artery anomalies as noninvasive in addition to conventional invasive coronary angiography for monitoring coronary artery disease.⁴

 Number of slices that can be captured simultaneously by raising number of detector rows has improved performance of cardiac CTA. The scan duration decreases as number of slices that may be captured simultaneously increases. Reconstruction artefacts are greatly reduced, & spatial resolution is improved. A 4-slice detector CT was used for the initial cardiac CT imaging.⁵

 Researchers wanted to see how non-invasive computed Tomography (CT) coronary angiography compared to invasive coronary angiography in terms of diagnosing coronary artery stenosis & how much it cost.

PATIENTS AND METHODS

This study was descriptive Observational study, thirty studied cases are in research. Patients are undergone ECG gated MDCT coronary angiography in CT unit in Radiology Department of National Heart Institute NHI was analyzed from PACS (Syngovia acquisition system) and we was included patients for detection of coronary stenotic lesions compared to outcomes of invasive coronary Angiography attached with studied cases including CABG patients.

 Research was authorized by the Institute's Ethics Committee, & studied cases gave their informed consent.

CT angiography should be chosen in conjunction with studying modalities like stress myocardial perfusion pictures or cardiac ultrasound outcomes, so that information obtained aids in management decisions rather than simply adding another layer of testing.

Inclusion criteria: Patients with coronary heart diseases symptoms or have history of CABG with their attached invasive coronary Angiography reports.

Exclusion criteria: Patients with impaired renal function Patients that have allergy to contrast, cardiac Arrhythmias as patients with atrial fibrillation (unless when rate-controlled) or other severe arrhythmias, ejection fraction less than thirty percent, pregnant women, BMI greater than forty (except when third generation Dual-Source CT (DSCT) 120 kv tube voltage is used) and calcium score 1000 or more.

Methods: Patient preparation: Reassurance of the patient, shaving of the chest hair, respiratory training, Subjects were advised to fast for four-six hours prior to  assessment, not to stop taking any medications, & to have their heart rate checked before the test. If heart rate is less than seventy beats each 60 seconds, an examination is performed. Individuals with heart rates more than seventy beats per minute were given a cardio-selective beta-blocker; 50/100 mg of Metoprolol, Bisprolol, & Atenolol orally 60 minutes before trial to achieve a low heart rate, assuming there were no contraindications to B-blockers.  Test was moved to a different location if heart rate remained above seventy beats each 60 seconds. Temporary coronary vasodilator (or coronary antispasmodic) for coronary spasm as Sublingual Nitrates (Dinitra). To assess sufferers' ability to hold their breath for an extended period of time, they were requested to execute deep inspiration and hold their breath without pressing (i.e., Valsalva maneuver). During the trial, case's compliance was monitored, as well as the ECG for any significant differences.

Contrast Material: A 120 ml bolus of water soluble non-ionic contrast (Omnipaque 300 mg Daiichi pharmaceutical, Tokyo, Japan) was injected through an 18 gauge cannula into upper limb vein (right antecubital vein in all cases to reduce left sided artefacts) at flow rate of 5 to 5.5 ml/sec. To keep proper opacification of the coronary vessels as well as the grafts a programmable dual head power injector pump (Med Rad; USA) was used to inject roughly 45 cc of saline at a flow rate of 5ml/sec to wash off contrast material from the SVC and right side of the heart, which could create artefacts (Med Rad; USA).

Reconstruction: During middle to end diastolic phase, 45-75 percent of R-R interval, the information are reconstructed (with slice thickness of 0.625mm & 0.4mm increments). If the picture quality in this test datasets isn't up to par, photographs were selected for additional analysis. All of the information gathered is sent to a second computer workstation. Based on the vessel shape and the quality of the MDCT data sets, various post-processing techniques are employed to analyse origin & course of the coronary arteries, such as maximum-intensity projection (MIP), curved multiplanar reconstruction (CPR), and volume rendering (VR). The music is played at a rate of 75 beats each 60 seconds.  Pipe time is padded to enable the reconstruction to adapt to minor heart rate fluctuations. Padding in sizes ranging from Forty to eighty msc is available.

Statistical analysis: SPSS 26.0 for Windows was used to gather, tabulate, & analyse all of the results (SPSS Inc., Chicago, IL, USA). The mean, SD, & (range) were used to convey quantifiable information, while absolute & relative frequencies were used to represent qualitative information (percentage). The Chi square (X2) test was done to see if there was a link between the qualitative factors. To assess the validity, 95 percent confidence intervals were determined for sensitivity, specificity, true positive rate (PVP), accuracy (PVN), & accuracy. A accuracy is calculated by the area under the ROC curve. A perfect test has an area of one.

RESULTS

Table 1:  study group's fundamental qualities (n=30)

This table demonstrated that mean year old of tested group was 55.53±14.2 ranging from 34 to 74 years. Most of cases (73.3%) were males, (50.0%) were smokers, and Most of cases (70.0%) were diabetic. About (50.0%) of cases had HTN and (26.7%) had dyslipidemia. Table (1)

Table 2: Frequency distribution of clinical manifestations of the studied group (n=30)

This table shows that all patients had chest pain (50.0% typical and 50.0% atypical chest pain). About (16.7%) suffered from dyspnea and Epigastric pain. Table (2)

Table 3: Frequency distribution of the affected vessels (n=53)

By evaluation of the studied patients, it was found that there are about 53 vessel affected. This table shows that about (43.4%) of cases had affection of left anterior descending artery while (18.9%) of cases had Right coronary artery & (15.1%) left circumflex artery. Table (3)

Table 4: Frequency distribution of the degree of stenosis of the affected vessels by CT angiography (n=53)

Regarding Provisional CT angiography diagnosis, this table shows that: (15.1%) had mild stenosis, (50.9%) moderate stenosis, (34.0%) severe stenosis with (84.9%) had significant stenosis (≥ 50). Table (4)

Table 5: Frequency distribution of the degree of stenosis of affected vessels by catheter (n=53)

Regarding Provisional catheter angiography diagnosis, this table shows that: (9.4%) had mild stenosis, (58.5%) moderate stenosis, (32.1%) severe stenosis with (90.6%) had significant stenosis (≥ 50). Table (5)

Table 6: Relation between CT angiography and catheter angiography is used to diagnose stenosis in coronary arteries. (n=53)

As in table (8), there was important association between stenosis marks detected by CT and catheter with catheter reported 17 severe cases from which CT detected 15 cases and 5 mild cases detected by catheter from which 4 cases were reported by CT angiography. Table (6)

Table 7: Validity of CT angiography in detection of coronary artery stenosis versus catheter as a gold standard

This table shows that the value of Sensitivity was (91.7%), specificity (80.0%), predictive value for positive (PVP) (50.0%), predictive value for negative (PVN) = (97.8%), & (90.6%) accuracy which means that CT angiography is a good screening instrument for detection of degree of coronary arteries stenosis. Table (7)

Table 8: Kappa agreement between CT angiography vs. catheter for detecting coronary artery stenosis

This table shows good agree between CT angiography & catheter in recognition of coronary artery stenosis as kappa coefficient was 0.565. Table (8)

Case Presentation

Case 1

Man with aging fifty admitted for suspected CA, diabetic and hypertensive, findings illustrated below:

Fig. 1: Curved multi-planar reform movements (cMPR) of the RCA (A), LAD (B), & LCX (C) show no stenosis in normal coronary arteries with 64-slice CT coronary angiography & ICA. In the mid-RCA & distal LCX, there are some minor motion artefacts (arrows). By not interfering with artery visualisation, the VR picture (D) defines 3D course of coronary arteries while also presenting venous opacification (open arrow).  Right (Inlay in A) & left coronary arteries are normal in the ICA (Inlay in C).

Case 2

 67 aged male presented with typical chest pain. Both 64- MDCT and CCA were done and they both modalities revealed same findings illustrated below:

Fig. 2: On the left (A) On the MPR & 3D-MIP photos (small arrow), CTCA pictures indicate occlusion of the mid RCA near the junction with the distal RCA, with full cutoff at the stump of the occlusion & no visibility of artery distal to the occlusion. On the right (B), as shown in the ICA the same finding has been identified (blue blocked arrow).