Quadruple-Rule-Out Computed Tomography Angiography (QRO-CT): A Novel Dual-Energy Computed Tomography Technique for the Diagnostic Work-Up of Acute Chest Pain.

BACKGROUND: Computerized tomography (CT) has been increasingly utilized in the differential diagnosis of acute chest pain. Combining the triple rule out CT angiography (TRO-CT) approach with dual-energy CT (DECT) can enhance the diagnostic capability by identifying myocardial perfusion deficiencies. This combination can yield a quadruple-rule-out computed tomography angiography (QRO-CT) technique. The aim of this study is to determine the efficacy of the QRO-CT. METHODS: Intraluminal diseases and abnormalities in the main coronary arteries and branches were investigated. The myocardial dark spots on the color-coded iodine map were identified as perfusion deficiencies. Pulmonary arteries and aorta were also evaluated. RESULTS: The study population consisted of 211 patients. The sensitivity, specificity, and positive and negative predictive values of QRO-CT for pulmonary embolism were 93.5%, 100%, 100%, and 95.3%, respectively. For obstructive coronary artery disease, the values were 96.1%, 93.4%, 89.2%, and 97.7%, respectively. For myocarditis, the values were 69.2%, 100%, 100%, and 93.6%, respectively. CONCLUSIONS: the QRO-CT method may successfully evaluate myocardial perfusion deficits, hence expanding the differential diagnosis capabilities of the standard TRO-CT method for myocarditis. It can provide useful information on myocardial perfusion, which may influence the choice to perform invasive catheterization in cases of coronary artery obstruction.

Utility of cardiac bioenzymes in predicting cardiovascular outcomes in SARS-CoV-2.

The relationship between coronavirus disease-19 (COVID-19) and cardiovascular diseases has been an important issue. Therefore, cardiac biomarkers and cardiac imaging have an important place in the diagnostic phase. It is important to know the relationship of biomarkers in COVID-19 so that we can understand the diagnosis of the disease, the predicted course and results after diagnosis.

Diagnosis of an Acute Anterior Wall Infarction in Dual-Energy CT.

Due to its high morbidity and mortality, myocardial infarction is the leading cause of death worldwide. Against this background, rapid diagnosis is of immense importance. Especially in case of an atypical course, the correct diagnosis may be delayed and thus lead to increased mortality rates. In this report, we present a complex case of acute coronary syndrome. A triple-rule-out CT examination was performed in dual-energy CT (DECT) mode. While pulmonary artery embolism and aortic dissection could be ruled out with conventional CT series, the presence of anterior wall infarction was only detectable on DECT reconstructions. Subsequently, adequate and rapid therapy was then initiated leading to survival of the patient.

Application of four-low scanning scheme of dual-source CT in triple-rule-out CT angiography for evaluation of acute chest pain / 实用放射学杂志

Objective To investigate the feasibility and value of the four-low scanning scheme of dual-source computed tomography(DSCT)on triple-rule-out computed tomography angiography(CTA)examination in acute chest pain.Methods Triple-rule-out CTA examination was performed on 150 patients with prospective electrocardiogram gating.They were divided into two groups:group A(100 kV)and group B(70 kV).According to different body mass index(BMI),group A were divided into Anon-overweight and Aoverweight,while group B were divided into Bnon-overweight and Boverweight.Subjective and objective evaluations[signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR),standard deviation(SD)]of the two groups were analyzed,and radiation-related parameters were recorded.Results There was no significant difference in subjective scores between the two groups(Kappa value=0.372,P＞0.05).CT value,SD,CNR and SNR were significantly different among the four subgroups(P＜0.05).SNR and CNR of A(B)non-overweight were higher than those of A(B)overweight(P＜0.05).Effective dose(ED)of group B decreased by 74.5％.Conclusion ADMIRE-3 and iterative beam-hardening correction(iBHC)combined with four-low scanning scheme of DSCT could improve the images quality of vascular,and reduce the radiation dose,contrast agent dosage and flow rate,which is worthy of promotion and application in patients with BMI≤30 kg/m2 acute chest pain triple-rule-out.

Triple rule-out computed tomography angiography: Evaluation of acute chest pain in COVID-19 patients in the emergency department.

BACKGROUND: The aim of this study was to define clinical evidence supporting that triple rule-out computed tomography angiography (TRO CTA) is a comprehensive and feasible diagnostic tool in patients with novel coronavirus disease 2019 (COVID-19) who were admitted to the emergency department (ED) for acute chest pain. Optimizing diagnostic imaging strategies in COVID-19 related thromboembolic events, will help for rapid and noninvasive diagnoses and results will be effective for patients and healthcare systems in all aspects. AIM: To define clinical evidence supporting that TRO CTA is a comprehensive and feasible diagnostic tool in COVID-19 patients who were admitted to the ED for acute chest pain, and to assess outcomes of optimizing diagnostic imaging strategies, particularly TRO CTA use, in COVID-19 related thromboembolic events. METHODS: TRO CTA images were evaluated for the presence of coronary artery disease, pulmonary thromboembolism (PTE), or acute aortic syndromes. Statistical analyses were used for evaluation of significant association between the variables. A two tailed P-value < 0.05 was considered statistically significant. RESULTS: Fifty-three patients were included into the study. In 31 patients (65.9%), there was not any pathology, while PTE was diagnosed in 11 patients. There was no significant relationship between the rates of pathology on CTA and history of hypertension. On the other hand, the diabetes mellitus rate was much higher in the acute coronary syndrome group, particularly in the PTE group (8/31 = 25.8% vs 6/16 = 37.5%, P = 0.001). The rate of dyslipidemia was significantly higher in the group with pathology on CTA while compared to those without pathology apart from imaging findings of the pneumonia group (62.5% vs 38.7%, P < 0.001). Smoking history rates were similar in the groups. Platelets, D-dimer, fibrinogen, C-reactive protein, and erythrocyte sedimentation rate values were higher in COVID-19 cases with additional pathologies. CONCLUSION: TRO CTA is an effective imaging method in evaluation of all thoracic vascular systems at once and gives accurate results in COVID-19 patients.

The triple rule out CT in acute chest pain: a challenge for emergency radiologists?

PURPOSE: To evaluate the feasibility of triple rule out computed tomography (TRO-CT) in an emergency radiology workflow by comparing the diagnostic performance of cardiovascular and general radiologists in the interpretation of emergency TRO-CT studies in patients with acute and atypical chest pain. METHODS: Between July 2017 and December 2019, 350 adult patients underwent TRO-CT studies for the assessment of atypical chest pain. Three radiologists with different fields and years of expertise (a cardioradiologist-CR, an emergency senior radiologist-SER, and an emergency junior radiologist-JER) retrospectively and independently reviewed all TRO-CT studies, by trans-axial and multiplanar reconstruction only. Concordance rates were then calculated using as reference blinded results from a different senior cardioradiologist, who previously evaluated studies using all available analysis software. RESULTS: Concordance rate was 100% for acute aortic syndrome (AAS) and pulmonary embolism (PE). About coronary stenosis (CS) for non-obstructive (<50%), CS concordance rates were 97.98%, 90.91%, and 97.18%, respectively, for CR, SER, and JER; for obstructive CS (>50%), concordance rates were respectively 88%, 85.7%, and 71.43%. Moreover, it was globally observed a better performance in the evaluation of last half of examinations compared with the first one. CONCLUSIONS: Our study confirm the feasibility of the TRO-CT even in an Emergency Radiology department that cannot rely on a 24/7 availability of a dedicated skilled cardiovascular radiologist. The "undedicated" radiologists could exclude with good diagnostic accuracy the presence of obstructive stenosis, those with a clinical impact on patient management, without needing time-consuming software and/or reconstructions.

Computed Tomographic Angiography for Risk Stratification in Patients with Acute Chest Pain - The Triple Rule-out Concept in the Emergency Department.

BACKGROUND: Acute chest pain is one of the most common reasons for Emergency Department (ED) visits and hospital admissions. As this could represent the first symptom of a lifethreatening condition, urgent identification of the etiology of chest pain is of utmost importance in emergency settings. Such high-risk conditions that can present with acute chest pain in the ED include Acute Coronary Syndromes (ACS), Pulmonary Embolisms (PE) and Acute Aortic Syndromes (AAS). DISCUSSION: The concept of Triple Rule-out Computed Tomographic Angiography (TRO-CTA) for patients presenting with acute chest pain in the ED is based on the use of coronary computed tomographic angiography as a single imaging technique, able to diagnose or exclude three lifethreatening conditions in one single step: ACS, AAS and PE. TRO-CTA protocols have been proved to be efficient in the ED for diagnosis or exclusion of life-threatening conditions and for differentiation between various etiologies of chest pain, and application of the TRO-CTA protocol in the ED for acute chest pain of uncertain etiology has been shown to improve the further clinical evaluation and outcomes of these patients. CONCLUSION: This review aims to summarize the main indications and techniques used in TRO protocols in EDs, and the role of TRO-CTA protocols in risk stratification of patients with acute chest pain.

Application of iodine contrast agent optimization protocol with fixed injection time in triple-rule-out CT examination of chest pain / 中华危重病急救医学

Objective To investigate the feasibility of using optimized protocol of iodine contrast agent with fixed injection time in triple-rule-out CT examination of acute chest pain patients. Methods A prospective study was conducted. The patients who underwent triple-rule-out CT examination of acute chest pain at the Second Hospital of Shanxi Medical University from September 2017 to June 2018 were enrolled. According to the patient's body mass index (BMI), they were divided into BMI ≤ 23 kg/m2 group and BMI > 23 kg/m2 group. The patients in each group were subdivided into two subgroups according to the random number table, and they were given two iodine contrast injection protocols with fixed injection time (14 s). Protocol 1 was performed with 55 mL of total iodinated contrast media: iodinated contrast media was first injected at 5.0 mL/s for 8 s, followed by the same contrast media injection at 2.5 mL/s for 6 s, finally followed by injection of 40 mL of saline at a rate of 2.5 mL/s. Protocol 2 with 60 mL of total iodinated contrast media: iodinated contrast media was first injected at 5.0 mL/s for 10 s, followed by the same contrast media injection at 2.5 mL/s for 4 s, finally followed by injection of 40 mL of saline at a rate of 2.5 mL/s. The primary and objective evaluation was conducted on the image quality of the patients' blood vessels in different segments. The primary score, CT value and contrast-to-noise ratio (CNR) of the pulmonary artery, coronary artery, aorta and total effective radiation dose for the examination were recorded. Results A total of 92 patients were enrolled in the analysis. There were 44 patients in BMI≤ 23 kg/m2 group, in which 22 patients received in protocol 1 and protocol 2, 48 patients in BMI > 23 kg/m2 group, in which 24 patients in protocol 1 and protocol 2, respectively. There was no significant difference in the effective radiation dose between the two subgroups receiving different injection protocols in different BMI groups (mSv: 6.7±1.1 vs. 6.5±0.8 between protocol 1 and protocol 2 in BMI ≤ 23 kg/m2 group; 7.8±1.0 vs. 8.0±1.1 between protocol 1 and protocol 2 in BMI > 23 kg/m2 group, both P > 0.05). In BMI ≤ 23 kg/m2 group, the CT value, CNR and primary scores of pulmonary artery images in patients receiving protocol 2 were significantly higher than those receiving protocol 1 [CT value (HU): 584±110 vs. 472±86 for main pulmonary artery, 561±93 vs. 467±78 for left pulmonary artery, 555±91 vs. 472±83 for right pulmonary artery; CNR: 24.2±7.5 vs. 18.7±4.6 for main pulmonary artery, 23.2±6.8 vs. 18.6±4.8 for left pulmonary artery, 22.9±6.7 vs. 18.8±4.7 for right pulmonary artery; primary score:4.0 (4.0, 4.0) vs. 3.5 (3.0, 4.0), all P < 0.05]; and there was no statistically significant difference in the primary or objective evaluation of coronary artery or aortic image quality between the two protocols. In BMI > 23 kg/m2 group, the CT value, CNR and primary scores of coronary artery and aortic images in patients receiving protocol 2 were significantly higher than those receiving protocol 1 [CT value (HU): 369±63 vs. 315±61 for proximal right coronary artery (RCA), 388±63 vs. 323±63 for proximal left coronary artery (LCA), 328±83 vs. 272±51 for ascending aorta, 348±82 vs. 272±49 for aortic arch; CNR: 15.0±4.6 vs. 12.3±4.7 for proximal RCA, 15.7±3.8 vs. 12.8±5.2 for proximal LCA, 13.2±5.3 vs. 10.4±4.1 for ascending aorta, 14.1±5.3 vs. 10.4±3.9 for aortic arch; primary score: 4.0 (3.0, 4.0) vs. 3.0 (3.0, 4.0) for coronary, 4.0 (3.0, 4.0) vs. 3.0 (2.0, 4.0) for aorta; all P < 0.05]; and there was no statistically significant difference in the primary or objective evaluation of pulmonary artery image quality between the two protocols. Conclusions The effective radiation dose of triple-rule-out CT examination of acute chest pain is relatively low. The low-dose iodine contrast agent application program with fixed injection time can meet the needs of clinical diagnosis of triple-rule-out CT examination of acute chest pain patients. For patients with BMI ≤ 23 kg/m2, both protocols 1 and 2 can obtain excellent image quality; in order to avoid the influence of superior vena cava artifacts, protocol 1 is recommended. For patients with BMI > 23 kg/m2, application protocol 2 can obtain stable, excellent image quality that is more suitable for clinical applications.

Triple rule-out computed tomography for risk stratification of patients with acute chest pain.

AIMS: Clinical evidence supporting triple rule-out computed tomography (TRO-CT) for rapid screening of cardiovascular disease is limited. We investigated the clinical value of TRO-CT in patients with acute chest pain. METHODS: We retrospectively enrolled 1024 patients who visited the emergency department (ED) with acute chest pain and underwent TRO-CT using a 128-slice CT system. TRO-CT was classified as "positive" if it revealed clinically significant cardiovascular disease including obstructive coronary artery disease, pulmonary thromboembolism, or acute aortic syndrome. The clinical endpoint was occurrence of a major adverse cardiovascular event (MACE) within 30 days, defined by a composite of all cause death, myocardial infarction, revascularization, major cardiovascular surgery, or thrombolytic therapy. Clinical risk scores for acute chest pain including TIMI, GRACE, Diamond-Forrester, and HEART were determined and compared to the TRO-CT findings. RESULTS: TRO-CT revealed clinically significant cardiovascular disease in 239 patients (23.3%). MACE occurred in 119 patients (49.8%) with positive TRO-CT and in 7 patients (0.9%) with negative TRO-CT (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value of TRO-CT was 95%, 88%, 54%, and 99%, respectively. TRO-CT was a better discriminator between patients with vs. without events as compared to clinical risk scores (c-statistics = 0.91 versus 0.64 to 0.71; integrated discrimination improvement = 0.31 to 0.37; p < 0.001 for all comparisons). Patients with a negative TRO-CT showed shorter ED stay times and admission rates compared to patients with positive TRO-CT, irrespective of clinical risk scores (p < 0.001 for all comparisons). CONCLUSION: Triple rule-out CT has high predictive performance for 30-day MACE and permits rapid triage and low admission rates irrespective of clinical risk scores.

Diagnostic Yield of Triple-Rule-Out CT in an Emergency Setting.

OBJECTIVE: The objective of the present study is to quantify the diagnostic yield of triple-rule-out (TRO) CT for the evaluation of acute chest pain in emergency department patients. MATERIALS AND METHODS: All TRO CT studies performed at our institution from 2006 to 2015 were reviewed. Scans were performed on a 256-MDCT scanner, with the use of ECG gating and a biphasic contrast injection. Radiology reports were reviewed to identify diagnoses that could explain chest pain, including coronary and noncoronary diagnoses, and significant incidental findings that did not account for the patient's presentation. The total numbers of coronary and noncoronary diagnoses and incidental findings were calculated. RESULTS: Four of 1196 total cases that were identified were excluded from the study because of inadequate image quality. A total of 970 patients (81.4%) had a negative study result without a significant coronary or noncoronary diagnosis. A total of 139 patients (11.7%) had significant coronary artery disease (50% stenosis or greater). One hundred six patients (8.9%) had a noncoronary diagnosis that could explain chest pain (p < 0.02), most commonly pulmonary embolism (28 patients [2.3%]), aortic aneurysm (24 patients [2.0%]), or pneumonia (20 patients [1.7%]). Thirty cases (27.3%) of pulmonary embolism and aortic pathologic findings would not have been detected with coronary CT angiography because of unopacified right-side circulation or limited z-axis coverage. A total of 528 incidental findings not considered to explain chest pain were noted in 418 patients (35.1%). CONCLUSION: In 8.9% of patients, TRO CT detected a significant noncoronary diagnosis that could explain acute chest pain, including pathologic findings that would not be identified on dedicated coronary CT angiography.

Prevalence of Acute Coronary Syndrome in Patients Suspected for Pulmonary Embolism or Acute Aortic Syndrome: Rationale for the Triple Rule-Out Concept.

BACKGROUND: The aims of the study were to evaluate the prevalence of acute coronary syndrome (ACS) among patients presenting with atypical chest pain who are evaluated for acute aortic syndrome (AAS) or pulmonary embolism (PE) with computed tomoangiography (CTA) and discuss the rationale for the use of triple rule-out (TRO) protocol for triaging these patients. METHODS: This study is a retrospective analysis of patients presenting with atypical chest pain and evaluated with thoracic (CTA), for suspicion of AAS/PE. Two physicians reviewed patient files for demographic characteristics, initial CT and final clinical diagnosis. Patients were classified according to CTA finding into AAS, PE and other diagnoses and according to final clinical diagnosis into AAS, PE, ACS and other diagnoses. RESULTS: Four hundred and sixty-seven patients were evaluated: 396 (84.8%) patients for clinical suspicion of PE and 71 (15.2%) patients for suspicion of AAS. The prevalence of ACS and AAS was low among the PE patients: 5.5% and 0.5% respectively (P = 0.0001), while the prevalence of ACS and PE was 18.3% and 5.6% among AAS patients (P = 0.14 and P = 0.34 respectively). CONCLUSION: The prevalence of ACS and AAS among patients suspected clinically of having PE is limited while the prevalence of ACS and PE among patients suspected clinically of having AAS is significant. Accordingly patients suspected for PE could be evaluated with dedicated PE CTA while those suspected for AAS should still be triaged using TRO protocol.

Triple Rule Out Versus Coronary CT Angiography in Patients With Acute Chest Pain: Results From the ACIC Consortium.

OBJECTIVES: This study sought to evaluate the diagnostic yield of triple rule out (TRO) versus coronary computed tomography angiography (CTA) scanning in patients with acute chest pain enrolled in a large statewide registry. BACKGROUND: Although TRO scans provide simultaneous evaluation of coronary artery disease (CAD), pulmonary embolism (PE), and aortic disease (AD), their use is not well defined. METHODS: Patients undergoing TRO or coronary CTA at 53 Michigan institutions for acute chest pain (in the emergency department or inpatient setting) in the ACIC (Advanced Cardiovascular Imaging Consortium) were included. Demographic characteristics, scan findings, and image quality parameters were compared between coronary CTA and TRO scans. The primary outcome was diagnostic yield, defined as obstructive CAD (>50% stenosis), PE, or AD; secondary outcomes were radiation dose, contrast volume, and image quality. RESULTS: From July 2007 to September 2013, 12,834 patients underwent computed tomography scanning (TRO, n = 1,555; coronary CTA, n = 11,279). The TRO group had more women (57.1% vs. 47.8%, p < 0.001). Diagnostic yield was similar (TRO, 17.4% vs. coronary CTA, 18.3%; p = 0.37), driven by CAD (15.5% vs. 17.2%, p = 0.093); PE and AD were 1.1% and 0.4% (p = 0.004) and 1.7% and 1.1% (p = 0.046). TRO had higher median radiation (9.1 mSv vs. 6.2 mSv; p < 0.0001) and mean contrast (113 ± 6 ml vs. 89 ± 17 ml; p < 0.0001) doses. Nondiagnostic images were frequent in TRO (9.4% vs. 6.5%; p < 0.0001). In emergency department patients, PE and AD were more often detected on TRO. Among inpatients, there were no differences in overall yield or in that of PE, AD, or CAD. CONCLUSIONS: TRO was associated with slightly higher yield of PE and AD, specifically in the emergency department. This benefit comes with higher nondiagnostic image quality, radiation, and contrast doses. Although TRO may be of value in selected patients, its indiscriminate use is not warranted. The appropriate use of TRO needs to be further defined. (Advanced Cardiovascular Imaging Consortium [ACIC]; NCT00640068).

Dual Source CT High Pitch Prospective Scan in Triple-rule-out Acute Chest Pain Examination / 中国医学影像学杂志

PurposeTo investigate the image quality of Dual Source CT (DSCT) high pitch prospective scan in acute chest pain examination by using triple-rule-out (TRO) protocol and its responses to heart beat rate change.Materials and Methods Thirty-two consecutive patients who planned to undergo TRO acute chest pain examination were enrolled and randomly divided into research group and control group. The conventional retrospective spiral scanning protocol was applied to the patients in the control group, while the high pitch prospective spiral scanning mode was used in the research group. CT value, noise level, SNR, CNR and radiation dosage in aorta and pulmonary arteries were recorded and compared between the two groups, and the image quality of the coronary arteries was scored subjectively.Results No significant difference was found in the aspects such as CT value, noise level, SNR, CNR radiation dosage in aorta and pulmonary arteries (P>0.05); however, the subjective scoring for coronary artery in the research group (85.5%) was significantly lower than that in the control group (93.9%) (χ2=8.33,P0.05). In addition, the radiation dosage in the control group was significantly higher than that in the research group [(20.8±6.2) mSvvs. (2.3±0.4) mSv;t=17.142,P<0.01].Conclusion DSCT high pitch prospective scanning in TRO protocol shows high success rate in examining patients with acute chest pain whose heart beat rate is lower than 80 beats/min and heart beat variance is less than 5 beats/min. The image quality has no difference with that derived from retrospective scan but with far more less radiation dose (2.3±0.4) mSv. This method thus is promising and can be widely promoted clinically.

Residents' performance in the interpretation of on-call "triple-rule-out" CT studies in patients with acute chest pain.

RATIONALE AND OBJECTIVES: To evaluate the performance of radiology residents in the interpretation of on-call, emergency "triple-rule-out" (TRO) computed tomographic (CT) studies in patients with acute chest pain. MATERIALS AND METHODS: The study was institutional review board-approved and Health Insurance Portability and Accountability Act compliant. Data from 617 on-call TRO studies were analyzed. Dedicated software enables subspecialty attendings to grade discrepancies in interpretation between preliminary trainee reports and their final interpretation as "unlikely to be significant" (minor discrepancies) or "likely to be significant" for patient management (major discrepancies). The frequency of minor, major and all discrepancies in resident's TRO interpretations was compared to 609 emergent non-electrocardiography (ECG)-synchronized chest CT studies using Pearson χ(2) test. RESULTS: Minor discrepancies occurred more often in the TRO group (9.1% vs. 3.9%, P < .001), but there was no difference in the frequency of major discrepancies (2.1% vs. 2.8%, P = .55). Minor discrepancies in the TRO group most commonly resulted from missed extrathoracic findings with missed liver lesions being the most frequent. Major discrepancies mostly encompassed cardiac and extracardiac vascular findings but did not result in unnecessary interventions, significant immediate changes in management, or adverse patient outcomes. CONCLUSIONS: On-call resident interpretation of TRO CT studies in patients with acute chest pain is congruent with final subspecialty attending interpretation in the overwhelming majority of cases. The rate of discrepancies likely to affect patient management in this domain is not different from emergent non-ECG-synchronized chest CT.

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.

BACKGROUND: 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. PURPOSE: 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. MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Myopericarditis diagnosed by a 64-slice coronary CT angiography "triple rule out" protocol.

We report a case of myopericarditis in a 30-year-old male complaining of shortness of breath. In an emergency department (ED) setting, the symptoms of myopericarditis may overlap with many disease entities and can be a challenging diagnosis to make. However, with the use of a 64-section coronary CT angiography in a "triple rule out" (TRO) protocol, we were able to detect a large pericardial effusion surrounding the heart and moderate global hypokinesis in the setting of normal-sized heart chambers and normal coronary arteries. We were further able to exclude pulmonary embolism and thoracic dissection. This is the first reported case of diagnosing myopericarditis using a TRO protocol. It demonstrates the usefulness of TRO in making an emergent diagnosis of myopericarditis while excluding other life-threatening diseases that can lead to earlier appropriate ED disposition and care.