Multislice CT angiography in coronary artery disease: Technical developments, radiation dose and diagnostic value

Left Main Ostial Stenosis in a Teenage Patient

Exertional chest pain in the setting of a structurally normal heart and no known arrhythmia are rarely thought to be related to cardiac etiology. Common non-cardiac etiologies of chest pain in the pediatric population include the following: lung infections, musculoskeletal, asthma, acid reflux, and anxiety. However, common cardiac etiologies that can cause exertional chest pain typically include the following: congenital heart disease, coronary anomalies, myocardial infections, left ventricular outflow obstruction, illicit drug use, and prothrombotic conditions. Rarely, pediatric patients present with an isolated finding of left main coronary artery ostial stenosis requiring intervention. Many of the published reports of left main ostial stenosis are in connection with other congenital heart disease, inflammation, or connective tissue disorders who have undergone percutaneous intervention. This report describes an 8-year-old patient with exertional chest pain for 5 years found to have isolated left ostial stenosis requiring coronary artery bypass grafting at the age of 13.

The value of CT coronary angiography for a comprehensive assessment of left circumflex artery in Kawasaki disease: 9 years of experience from a tertiary center

Background

Transthoracic echocardiography (TTE) has traditionally been the primary method for coronary imaging in children with Kawasaki disease (KD). We aimed to evaluate coronary artery lesions (CALs) of the left circumflex artery (LCx) in KD on computed tomography coronary angiography (CTCA).

Methods

Over a 9-year period (November 2013-December 2022), 225 children with KD underwent radiation-optimized CTCA on a 128-slice dual-source platform. TTE was performed on the same day, or a day prior or after CTCA.

Findings

On CTCA, LCx CALs were seen in 41/225 (18.2%) patients. However, TTE detected CALs in only one third of these patients [15/41 (36.6%)]. CTCA showed 47 LCx CALs in 41 patients-aneurysms in 39 patients (40 fusiform, 2 saccular; 7 giant aneurysms), stenoses in 3, and thrombosis in 2. Thromboses and stenoses were both missed on TTE. Proximal LCx aneurysms were seen in 39 patients-of these, 12 had distal extension. Six patients had distal LCx aneurysms without proximal involvement and 2 non-contiguous multiple aneurysms. Four (9.75%) patients had isolated LCx involvement. Based on CTCA findings, treatment protocols had to be modified in 3/41 (7.3%) patients.

Interpretation

This study highlights anatomical findings of LCx involvement in KD. Isolated LCx CALs were noted in 4/41 (9.75%) patients. TTE alone proved inadequate for LCx assessment in children with KD. With abnormalities detected in 18.2% of cases, including those missed by TTE, CTCA emerges as an essential imaging modality. The findings have implications for treatment planning and follow-up strategies in children with KD.

Funding

None.

Clinical audit of the image quality and customised contrast volume using P3T contrast injection software versus standard injection protocol in CT coronary angiography

INTRODUCTION

The implications of shorter scan time and lower tube voltage in the dual-source CT coronary angiography (CTCA) scan protocol necessitate the adaptation of contrast media (CM) injection parameters. This audit evaluates the coronary arteries' vascular attenuation and image quality by comparing the personalised patient protocol technology (P3T) contrast injection software with standard injection protocol. The secondary aim is to determine the relationship between CM volume and the patient's weight.

METHODOLOGY

A Siemens Somatom Definition Force CT Unit was used to scan 30 sets of patients between August 2020 and October 2020. Patients were selected retrospectively and separated into Standard Injection and P3T injection protocols. An experienced radiologist blinded to the groups reviewed the coronary vessels' contrast enhancement and image quality.

RESULTS

Overall, the mean HU of all the main coronary artery vessels obtained from P3T injection software reached above 350 HU and was diagnostically sufficient. The mean attenuation at the proximal region of RCA in the 80-99 kg weight category was significantly higher in the P3T injection software than the standard injection protocol (p < 0.001). The CM volume proposed by P3T injection software for 40-59 kg was approximately 57 ± 5 mls, while 75 ml was used for the standard injection protocol.

CONCLUSION

P3T injection software in CTCA resulted in an adequate diagnostic attenuation of coronary arteries (>350HU) in all weight groups, most effectively in the higher weight group, while maintaining diagnostic image quality. Further, the P3T software reduces CM volumes in lower-weight patients.

IMPLICATIONS

P3T software enables reducing CM volume in lower-weight patients while improving vascular enhancement in CTCA scans in higher-weight patients.

Cardiac CT: Competition, complimentary or confounder

Coronary CT angiography (CCTA) has been gradually adopted into clinical practice over the last two decades. CCTA has high diagnostic accuracy, prognostic value, and unique features such as assessment of plaque composition. CCTA-derived functional assessment techniques such as fractional flow reserve and CT perfusion are also available and can increase the diagnostic specificity of the modality. These properties propound CCTA as a competitor of functional testing in diagnosis of obstructive CAD, however, utilizing CCTA in a concomitant fashion to potentiate the performance of the latter can lead to better patient care and may provide more accurate prognostic information. Although multiple diagnostic challenges such as evaluation of calcified segments, stents, and small distal vessels still exist, the technologic developments in hardware as well as growing incorporation of artificial intelligence to daily practice are all set to augment the diagnostic and prognostic role of CCTA in cardiovascular disorders.

Chest Pain Evaluation: Diagnostic Testing

Chest pain/discomfort (CP) is a common symptom and can be a diagnostic dilemma for many clinicians. The misdiagnosis of an acute or progressive chronic cardiac etiology may carry a significant risk of morbidity and mortality. This review summarizes the different options and modalities for establishing the diagnosis and severity of coronary artery disease. An effective test selection algorithm should be individually tailored to each patient to maximize diagnostic accuracy in a timely fashion, determine short- and long-term prognosis, and permit implementation of evidence-based treatments in a cost-effective manner. Through collaboration, a decision algorithm was developed (www.chowmd.ca/cadtesting) that could be adopted widely into clinical practice.

Role of computed tomography in adult congenital heart disease: A review

Due to advances in cardiac surgery, perioperative care and transcatheter interventions, the majority of infants with congenital heart disease (CHD) now survive and reach adulthood. Transthoracic Echocardiography (TTE) is considered the primary imaging modality in evaluation of patients with CHD. However, in adults it can be limited due to several reasons. Although cardiac magnetic resonance (CMR) is extremely useful in evaluating cardiac morphology and function, it is not widely available, takes a long time to obtain images, and cannot be done in severely ill patients or patients that have claustrophobia. Due to high spatial and temporal resolution, isotropic imaging fast imaging and wide availability, multidetector computed tomography (MDCT) has emerged as an excellent alternative modality in the evaluation of adult congenital heart disease (ACHD). It can be performed on patients with hardware and those with claustrophobia, due to shorter image acquisition time. In this article, the commonly encountered congenital heart disorders in adults are reviewed, whether incidentally discovered on a computed tomography (CT), on a CT done to evaluate sequela of unknown CHD, or known treated CHD. To appropriately perform and evaluate CT imaging for postoperative correction or palliation congenital heart disease in adults, the imager should know the detailed cardiac anatomy, details of the operative technique used, and be familiar with the common short and long term post-operative complications.

Increased symmetric dimethylarginine, but not asymmetric dimethylarginine, concentrations are associated with transient myocardial ischemia and predict outcome

Objective

Asymmetric and symmetric dimethylarginines (ADMA and SDMA) are endothelial dysfunction markers. ADMA inhibits synthesis of nitric oxide. We aimed to analyze both markers in patients with coronary artery disease (CAD) who were referred for stress/rest myocardial perfusion scintigraphy (MPS).

Methods

All patients underwent a 2-day dipyridamole (DP) stress/rest protocol. Thereafter, patients with transient myocardial perfusion abnormality were followed up and their coronary blood flow was quantitatively assessed. Venous blood was taken before and after DP stress to measure markers.

Results

Baseline ADMA and SDMA concentrations were significantly higher in patients with CAD compared with healthy subjects. Pre- and post-stress SDMA concentrations were significantly higher in patients with transient myocardial perfusion abnormality compared with those with negative MPS results. However, ADMA and L-arginine concentrations were not significantly different between the two groups. None of the markers were significantly different between patients with angiographically proven low coronary flow and those with normal coronary flow. Pre-stress SDMA concentrations were an independent predictor of cardiovascular mortality during a 8-year follow-up.

Conclusions

Elevated serum SDMA concentrations may be helpful for selecting high-risk patients with CAD if there is any doubt in interpreting MPS. SDMA concentrations may also predict cardiovascular outcome.

Association of Difference in Coronary Sinus Diameter by Computed Tomographic Angiography Between Patients in and Not in Stable Atherosclerotic Plaque(S)

Background

Pathological finding fail to describe the morphology of coronary arterial plaques. Retrograde cardiac arteriography is a complicated procedure and does not detect all left posterior and marginal veins of the heart. Magnetic resonance angiography has long scan time and low spatial resolution. The objective of the present study was to assess the possible utility of the difference in coronary sinus diameter to quantify stable atherosclerotic plaque(s) using 256-slice coronary computed tomographic angiography.

Material/Methods

A total of 336 patients were divided into 2 groups with 168 patients each. Patients who had heart failure were included in the study group and those who did not were included in the non-study group. Patients were subjected to cross-sectional study. Cardiovascular images were performed with 256-slice coronary computed tomographic angiography with a prospective electrocardiogram and clinical manifestation. Two-tailed paired t test following Dunnett’s multiple comparison tests was performed for the quantitative measurement of coronary computed tomographic angiography and clinical manifestation at 99% confidence level.

Results

The clinical manifestation did not clearly show cardiac abnormality. The diameters of the superoinferior coronary sinus ostium was than that of the anteroposterior coronary sinus ostium, (p<0.0001, q=26.325). There was the difference in size of the coronary sinus ostium between patients in and not in heart failure (p<0.0001). The study group patients had longer coronary sinuses than patients in the non-study group (p<0.0001).

Conclusions

256-slice computed tomographic angiography is a feasible and is non-invasive bio-tool for evaluation of coronary artery anatomy.

Actual Dose-Reduction Strategies in Cardiac Computed Tomography

Computed tomography (CT) in cardiac examination is a powerful imaging tool that has developed rapidly during the last decade and continues to increase its potential by bringing novel technologies. Due to its noninvasive character, cardiac CT became a largely used method in detecting coronary diseases or functional issues at the expense of conventional coronary angiography. The accuracy of images has also increased, especially since new generation dual-source multi-slice detectors were developed. Although there are continuous improvements that serve to gain better-quality images, thus increasing their diagnostic accuracy, there is an inconvenient that became a serious topic for debate in the current literature: exposure to higher doses of radiation during cardiac CT examinations. Fortunately, physicians and manufacturers are taking into consideration the need to apply new strategies for radiation dose-reduction. Thus, this objective can be achieved by using patient-tailored dose-reduction strategies and by modulating the technical features of the CT scanners in order to gather high-quality images with minimal radiation exposure. The aim of this manuscript was to review the current literature data on dose-reduction strategies that are used for cardiovascular computed tomography scans.

Quantitative assessment on coronary computed tomography angiography (CCTA) image quality: comparisons between genders and different tube voltage settings

BACKGROUND

This study was carried out to quantify and compare the quantitative image quality of coronary computed tomography angiography (CCTA) between genders as well as between different tube voltages scan protocols.

METHODS

Fifty-five cases of CCTA were collected retrospectively and all images including reformatted axial images at systolic and diastolic phases as well as images with curved multi planar reformation (cMPR) were obtained. Quantitative image quality including signal intensity, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of right coronary artery (RCA), left anterior descending artery (LAD), left circumflex artery (LCx) and left main artery (LM) were quantified using Analyze 12.0 software.

RESULTS

Six hundred and fifty-seven coronary arteries were evaluated. There were no significant differences in any quantitative image quality parameters between genders. 100 kilovoltage peak (kVp) scanning protocol produced images with significantly higher signal intensity compared to 120 kVp scanning protocol (P<0.001) in all coronary arteries in all types of images. Higher SNR was also observed in 100 kVp scan protocol in all coronary arteries except in LCx where 120 kVp showed better SNR than 100 kVp.

CONCLUSIONS

There were no significant differences in image quality of CCTA between genders and different tube voltages. Lower tube voltage (100 kVp) scanning protocol is recommended in clinical practice to reduce the radiation dose to patient.

Non-invasive assessment of low- and intermediate-risk patients with chest pain

Coronary artery disease (CAD) remains a significant global public health burden despite advancements in prevention and therapeutic strategies. Common non-invasive imaging modalities, anatomic and functional, are available for the assessment of patients with stable chest pain. Exercise electrocardiography is a long-standing method for evaluation for CAD and remains the initial test for the majority of patients who can exercise adequately with a baseline interpretable electrocardiogram. The addition of cardiac imaging to exercise testing provides incremental benefit for accurate diagnosis for CAD and is particularly useful in patients who are unable to exercise adequately and/or have uninterpretable electrocardiograms. Radionuclide myocardial perfusion imaging and echocardiography with exercise or pharmacological stress provide high sensitivity and specificity in the detection and further risk stratification of patients with CAD. Recently, coronary computed tomography angiography has demonstrated its growing role to rule out significant CAD given its high negative predictive value. Although less available, stress cardiac magnetic resonance provides a comprehensive assessment of cardiac structure and function and provides a high diagnostic accuracy in the detection of CAD. The utilization of non-invasive testing is complex due to various advantages and limitations, particularly in the assessment of low- and intermediate-risk patients with chest pain, where no single study is suitable for all patients. This review will describe currently available non-invasive modalities, along with current evidence-based guidelines and appropriate use criteria in the assessment of low- and intermediate-risk patients with suspected, stable CAD.

Effectiveness of Using Dual-source CT and the Upshot it creates on Both Heart Rate and Image Quality

BACKGROUND

Early detection of coronary artery disease (CAD) is important because of the high morbidity and mortality rates. As invasive coronary angiography (ICA) is an invasive procedure, an alternative diagnostic method; coronary computed tomography angiography (CTA), has become more widely used by the improvements in detector technology.

AIMS

In this study, we aimed to examine the accuracy and image quality of high-pitch 128-slice dual-source CTA taking the ICA as reference technique. We also aimed to compare the accuracy and image quality between different heart rate groups of >70 beates per minute (bpm) and ≤70 bpm.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Among 450 patients who underwent coronary CTA with the FLASH spiral technique, performed with a second generation dual-source computed tomography device with a pitch value of 3.2, 102 patients without stent and/or bypass surgery history and clinically suspected coronary artery disease who underwent ICA within 15 days were enrolled. Image quality was assessed by two independent radiologists using a 4-point scale (1=absence of any artifacts- 4=non-evaluable). A stenosis >50% was considered significant on a per-segment, per-vessel, and per-patient basis and ICA was considered the reference method. Radiation doses were determined using dose length product (DLP) values detected by the computed tomography (CT) device. In addition, patients were classified into two groups according to their heart rates as ≤70 bpm (73 patients) and >70 bpm (29 patients). The relation between the diagnostic accuracy and heart rate groups were evaluated.

RESULTS

Overall, 1495 (98%) coronary segments were diagnostic in 102 patients (32 male, 70 female, mean heart rate: 65 bpm). There was a significant correlation between image quality and mean heart rate in the right coronary artery (RCA) segments. The effective radiation dose was 0.98±0.09 mili Sievert (mSv). On a per-patient basis, sensitivity, specificity, and positive and negative predictive values were 93.8%, 88.8%, 93.8% and 88.8%, respectively. These values were also similar in per-vessel and per-segment basis. Two different groups categorized by mean heart rate had almost similar results in terms of the diagnostic power of dual-source CTA.

CONCLUSION

CTA with a high pitch value is a reliable, non-invasive diagnostic method that can CAD with low radiation doses not only in patients with a heart rate below 70 bpm, but also in patients with higher heart rates.

Effect of heart rate on the diagnostic accuracy of 256-slice computed tomography angiography in the detection of coronary artery stenosis: ROC curve analysis

The aim of the present study was to investigate the effect of heart rate (HR) on the diagnostic accuracy of 256-slice computed tomography angiography (CTA) in the detection of coronary artery stenosis. Coronary imaging was performed using a Philips 256-slice spiral CT, and receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic value of 256-slice CTA in coronary artery stenosis. The HR of the research subjects in the study was within a certain range (39-107 bpm). One hundred patients suspected of coronary heart disease underwent 256-slice CTA examination. The cases were divided into three groups: Low HR (HR <75 bpm), moderate HR (75≤ HR <90 bpm) and high HR (HR ≥90 bpm). For the three groups, two observers independently assessed the image quality for all coronary segments on a four-point ordinal scale. An image quality of grades 1-3 was considered diagnostic, while grade 4 was non-diagnostic. A total of 97.76% of the images were diagnostic in the low-HR group, 96.86% in the moderate-HR group and 95.80% in the high-HR group. According to the ROC curve analysis, the specificity of CTA in diagnosing coronary artery stenosis was 98.40, 96.00 and 97.60% in the low-, moderate- and high-HR groups, respectively. In conclusion, 256-slice coronary CTA can be used to clearly show the main segments of the coronary artery and to effectively diagnose coronary artery stenosis. Within the range of HRs investigated, HR was found to have no significant effect on the diagnostic accuracy of 256-slice coronary CTA for coronary artery stenosis.

Radiation dose and diagnostic accuracy of high-pitch dual-source coronary angiography in the evaluation of coronary artery stenoses

PURPOSE

"Flash Spiral" imaging is a new prospective ECG-triggered spiral scan mode that uses a very high-pitch for coronary computed tomography angiography (CTA). This enables complete image acquisition within one cardiac cycle with a very low radiation exposure. The aim of this study was to investigate the diagnostic accuracy, image quality, and effective radiation dose of prospectively ECG-triggered high-pitch spiral method (Flash spiral mode) of coronary CTA using dual-source technology for the evaluation of coronary artery stenoses.

MATERIAL AND METHODS

The study included 186 consecutive patients (115men, 71women; mean age: 53.37 years) who underwent coronary CTA. Coronary CTA was performed with a 128×2-slice dual-source CT (Somatom Definition Flash, Siemens, Germany) using a prospectively ECG-triggered high-pitch spiral mode. Patients were divided into three groups according to heart rate (≤65bpm, 66-75bpm, ≥76bpm) and body mass index (BMI) (20-24kg/m(2), 25-29kg/m(2), 30-34kg/m(2)) values. The correlation between heart rates, image quality and BMI values are investigated. A four-point scale (1=excellent, 4=poor/non-diagnostic) was used to rank the comparative image quality. Effective radiation doses were calculated. Also the correlation between radiation dose, sex and BMI values were investigated. In addition, diagnostic accuracy of CTA for detection of significant (≥50%) coronary artery stenoses was compared with invasive coronary angiography findings of 612vessel segments in 38patients. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy rate were calculated.

RESULTS

A total of 2976coronary artery segments were present. Of all coronary artery segments, 2381 (80%) had an image quality score of 1, and 1.5% segments were rated as "poor/non-diagnostic". When the correlation between heart rate and image quality is investigated, there was a significant difference between ≤65bpm and ≥76bpm groups. However, there was no significant difference between ≤65bpm and 66-75bpm groups. The mean effective dose was found as 1.3mSv (min: 0.5, max: 2.4mSv). The correlation between effective radiation dose and BMI was moderate. However, the correlation between gender and radiation dose was significant. Sensitivity, specificity, negative predictive value and accuracy of coronary CTA on a per-vessel segment were 90.1%, 97.4%, 98.6%, and 96.5%, respectively.

CONCLUSIONS

Prospectively ECG-triggered high-pitch spiral mode coronary CTA provides high image quality and diagnostic accuracy, with very low radiation dose for evaluation and exclusion of coronary artery stenoses.

Improving Patient to Patient CT Value Uniformity with an Individualized Contrast Medium Protocol Tailored to Body Weight and Contrast Medium Concentration in Coronary CT Angiography

To determine whether body weight and concentration dependent contrast medium (CM) injection protocols can improve patient to patient CT value uniformity more than the conventional injection protocols with fixed injection parameters in coronary CT angiography (CCTA), one hundred and sixty patients who underwent CCTA were prospectively randomized into two groups. Group A (n = 80) used individualized-protocol with adjusted injection rate based on patient weight and contrast medium concentration to obtain constant iodine load of 280 mgI/kg while group B (n = 80) followed the conventional contrast injection protocol with total injection volume of 80ml and constant injection rate of 5.5ml/s. For both groups, patients were further divided into four subgroups with different CM concentrations: A1, B1 (300 mg I/ml); A2, B2 (320 mg I/ml); A3, B3 (350 mg I/ml) and A4 and B4 (370 mg I/ml). For each patient, the CT values of the ascending aorta, left ventricle and coronary arteries were measured. One-way analysis of variance was used to compare CT values among subgroups. Among the subgroups of A, sufficient attenuation of greater than 300HU was obtained in all target vessels with no difference among them. Among the subgroups of B, the CT values had significant difference in left ventricle, left circumflex branch, proximal and distal segment of the right coronary artery (all p < 0.05), and the attenuation with 300 mg I/ml CM concentration was significantly lower than that with 370 mg I/ml. Compared with group B, group A used less volume (62.83 ml vs. 80.00 ml, P<0.001) and lower rate (5.21 ml/s vs. 5.50 ml/s, P<0.001) of CM. Compared with the conventional contrast medium injection protocol with fixed volume and injection rate, the individualized-protocol based on patient weight and contrast concentration provides overall contrast dose reduction and achieves more homogenous attenuation among different coronary vessels and patients.

Diagnostic usefulness of quantitative tissue velocity imaging and anatomic M-mode echocardiography for coronary artery diseases: A pilot study

BACKGROUND AND OBJECTIVE

To explore the potential clinical usefulness and determine optimal diagnostic criteria of quantitative tissue velocity imaging and anatomic M-mode echocardiography in patients with coronary artery disease (CAD).

METHODS

We used quantitative tissue velocity imaging for the measurement of systolic myocardial velocity, and anatomic M-mode echocardiography for the measurement of ventricular wall-thickening fraction in 44 subjects with suspected CAD. Subjects were classified as patients if coronary angiography demonstrated a stenosis ≥ 50%, and as controls if it was strictly normal. The diagnostic criteria, sensitivity, and specificity were assessed by receiver-operator curves.

RESULTS

Controls had greater mean systolic myocardial velocity and ventricular wall-thickening fraction in the basal (6.59 ± 1.25 cm/s and 0.44 ± 0.05) and mid segment (5.23 ± 0.93 cm/s and 0.43 ± 0.04) than patients (5.02 ± 1.17 cm/s and 0.29 ± 0.04, 3.27 ± 1.29 cm/s and 0.29 ± 0.04, respectively, p < 0.001). Mid-segment ventricular wall-thickening fraction offered 95% sensitivity (95% CI 88.7% to 98.4%), and 98.3% specificity (95% CI 90.9% to 1.0) with an optimal cut-off point of 0.349, yielding better results than systolic myocardial velocity, which provided 83% sensitivity (95% CI 74.2% to 89.8%), 90% specificity (95% CI 79.5% to 96.2%), and optimal cut-off point 4.47. The combination of systolic myocardial velocity and ventricular wall-thickening fraction offered 97% sensitivity (95% CI 91.5% to 99.4%)

CONCLUSIONS

Mid-segment ventricular wall-thickening fraction might be suitable for the evaluation of patients with CAD.

Coronary CT angiography: Diagnostic value and clinical challenges

Coronary computed tomography (CT) angiography has been increasingly used in the diagnosis of coronary artery disease due to improved spatial and temporal resolution with high diagnostic value being reported when compared to invasive coronary angiography. Diagnostic performance of coronary CT angiography has been significantly improved with the technological developments in multislice CT scanners from the early generation of 4-slice CT to the latest 320- slice CT scanners. Despite the promising diagnostic value, coronary CT angiography is still limited in some areas, such as inferior temporal resolution, motion-related artifacts and high false positive results due to severe calcification. The aim of this review is to present an overview of the technical developments of multislice CT and diagnostic value of coronary CT angiography in coronary artery disease based on different generations of multislice CT scanners. Prognostic value of coronary CT angiography in coronary artery disease is also discussed, while limitations and challenges of coronary CT angiography are highlighted.

Beta-blocker administration protocol for prospectively ECG-triggered coronary CT angiography

The aim of this article is to discuss the protocol of beta-blockers that is commonly used for prospectively ECG-triggered coronary computed tomography angiography (CCTA). It is essential to ensure a low and regular heart rate in patients undergoing prospectively ECG-triggered CCTA for optimal visualization of coronary arteries. Although early generations of computed tomographyscanners are not applicable to be tailored according to patients’ heart rate, a low and regular heart rate is possible to be achieved by the administration of medications according to the beta-blocker protocol. Beta-blocker can be safely administered to reduce patients’ heart rate for CCTA examination if patients are screened for certain contraindications.

Coronary artery calcium score: a review

Context

Coronary artery disease (CAD) is the foremost cause of death in many countries and hence, its early diagnosis is usually concerned as a major healthcare priority. Coronary artery calcium scoring (CACS) using either electron beam computed tomography (EBCT) or multislice computed tomography (MSCT) has been applied for more than 20 years to provide an early CAD diagnosis in clinical routine practice. Moreover, its association with other body organs has been a matter of vast research.

Evidence Acquisition

In this review article, techniques of CACS using EBCT and MSCT scanners as well as clinical and research indications of CACS are searched from PubMed, ISI Web of Science, Google Scholar and Scopus databases in a time period between late 1970s through July 2013 and following appropriate selection, dealt with. Moreover, the previous and ongoing research subjects and their results are discussed.

Results

The CACS is vastly applied in early detection of CAD and in many other research fields.

Conclusions

CACS has remarkably changed the screening techniques to detect CAD earlier than before and is generally accepted as a standard of reference for determination of risk of further cardiac events.

Diagnostic accuracy of 320-slice computed tomography angiography for detection of coronary artery stenosis: meta-analysis

OBJECTIVE

This study aims to review the recent literatures on the diagnostic accuracy of 320-slice computed tomography angiography (CTA) for detection of coronary artery stenosis, with invasive coronary angiography (ICA) as the reference standard.

METHODS

A PubMed and EMBASE cross-search of the literatures on use of 320-slice CTA compared with ICA for detection of coronary artery stenosis, with publication date limited to January 1, 2008 to December 31, 2012. Individual and pooled sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated at the patient-, vessel- and segment-level. A positive result was defined as greater than or equal to 50%-diameter stenosis.

RESULTS

A total of ten studies were included in the present meta-analysis, examining 1088 patients, 1629 vessels and 12,406 segments. The meta-analysis at the patient-level indicated a pooled sensitivity of 93% (95%CI: 91%-95%), specificity of 86% (95%CI: 82%-89%), PPV of 90% (95%CI: 87%-92%) and NPV of 90% (95%CI: 87%-93%). At the vessel-level, the pooled sensitivity was 92% (95%CI: 89%-94%), specificity 95% (95%CI: 94%-96%), PPV 87% (95%CI: 83%-90%), and NPV 97% (95%CI: 96%-98%). At the segment-level, the pooled sensitivity was 78% (95%CI: 76%-80%), specificity 98% (95%CI: 97%-98%), PPV 82% (95%CI: 80%-84%), and NPV 97% (95%CI: 97%-97%).

CONCLUSIONS

320-CTA can effectively identify the majority of patients with coronary artery disease (CAD). The high NPV makes it as an effective noninvasive alternative to ICA for the exclusion of stenosis.

Sudden death and physical exercise: timely diagnosis of congenital anomalies of the coronary arteries with the new 320-slide multi-detector computed tomography

Congenital abnormalities of the coronary arteries here described are an uncommon form of structural heart disease. Nevertheless, they deserve attention because may cause chest pain and, in some cases, sudden cardiac death even during exercise. Traditional angiography has limitations due to its projectional and invasive nature. The recent development of the 320-slide multi-detector computer tomography with low radiation exposure has the potential to modify the current diagnostic work-up, as it allows even in young people a timely identification of clinical significant coronary anomalies minimizing the risks related to radiation exposure.

Estimated radiation dose and image quality comparison of the scan protocols in dual-source computed tomography coronary angiography

INTRODUCTION

Radiation exposure from computed tomography coronary angiography (CTCA) is of particular concern and several techniques have been introduced to lower the radiation dose. In this study, we aimed to compare the diagnostic image quality and estimated radiation dose of the three CTCA acquisition protocols in a recently introduced second generation dual-source computed tomography.

METHODS

Two hundred consecutive subjects underwent dual-source CTCA by using high-pitch spiral, sequential and retrospective spiral protocols. Effective radiation dose, expressed in millisieverts, was calculated as the product of the dose-length product times a conversion factor of 0.014. Image quality was evaluated on a per-segment basis, with a four-point scale.

RESULTS

For the high-pitch spiral, sequential and retrospective spiral protocols, mean effective radiation doses were 1.41 ± 0.56, 5.50 ± 2.06 and 7.79 ± 2.25 mSv and mean per-subject image scores were 2.8 ± 0.7, 2.2 ± 0.8 and 2.5 ± 0.8, respectively. Radiation dose of the high-pitch mode was significantly lower (P < 0.001) than the sequential and retrospective spiral modes, and statistical analysis for image quality revealed a significant difference between the high-pitch spiral and the sequential modes (P < 0.05).

CONCLUSION

Dual-source CTCA using high-pitch acquisition considerably lowers radiation exposure in subjects with a low and stable heart rate and maintains good image quality, especially when the subjects have a body mass index ≤25 and a tube voltage of 80 or 100 kV is used. However, when sequential and retrospective spiral modes are used in the same device, mean radiation doses can increase roughly three and five times more, respectively.

Coronary artery calcium score: Re-evaluation of its predictive value for coronary artery disease

Coronary artery disease is the leading cause of death in advanced countries and its prevalence is increasing among the developing countries. Cardiac computed tomography (CT) has been increasingly used in the diagnosis of coronary artery disease due to its rapid improvements in multislice CT scanners over the last decade, and this less-invasive technique has become a potentially effective alternative to invasive coronary angiography. Quantifying the amount of coronary artery calcium with cardiac CT has been widely accepted as a reliable non-invasive technique for predicting risk of future cardiovascular events. However, the main question that remains uncertain is whether routine, widespread coronary artery calcium scoring in an individual patient will result in an overall improvement in quality of care and clinical outcomes. In this commentary, we discuss a current issue of the clinical value of coronary artery calcium scoring with regard to its value of predicting adverse cardiac events. We also discuss the applications of coronary artery calcium scores in patients with different risk groups.

Multiple coronary artery-left ventricular fistulas causing sudden death in a young woman

Multiple coronary artery fistulae arising from right and left coronary arteries were found at autopsy in a 22-year-old woman, dying suddenly while playing football. This is the fifth pathologic description of this finding with biventricular involvement. We found microscopic evidence of postischemic scars and foci of myocardial calcifications in the left ventricular wall.

Coronary computed tomography angiography in coronary artery disease

AIM

To investigate the research directions of coronary computed tomography (CT) angiography in the diagnosis of coronary artery disease (CAD) based on a systematic review of the literature.

METHODS

A search of articles on coronary CT angiography in the diagnosis of CAD was performed during a 6-year-period between 2005 and 2010 from five main radiology journals namely, Radiology, American Journal of Roentgenology, European Radiology, European Journal of Radiology and British Journal of Radiology. Analysis of the references was focused on the research directions of coronary CT angiography with regard to the type of studies in terms of diagnostic value, application of dose-reduction strategies and resultant effective radiation doses with use of these techniques.

RESULTS

One hundred and forty two studies were identified which met the selection criteria and were included in the analysis. 64-slice CT (single source and dual-source CT) dominated 78% of the coronary CT angiography studies. Prior to 2007, research was focused on the diagnostic value of coronary CT angiography, but since 2008 more attention has been paid to radiation dose reduction. Radiation dose was reported in 64 studies, representing 45% of total studies published in the five radiology journals. Various dose-saving strategies have been implemented and prospective electrocardiography-triggering and high pitch techniques were found to be the most effective approaches for radiation dose reduction, with the corresponding mean effective dose being 3.5 ± 1.9 mSv and 1.7 ± 0.6 mSv, respectively.

CONCLUSION

This review shows that the current research in coronary CT angiography has shifted from the previous focus on diagnostic accuracy in CAD to more emphasis on radiation dose reduction.