Aortic dissection: diagnosis and follow-up with helical CT

MR Angiography for Aortic Diseases

Aortic pathologic conditions represent diverse disorders, including aortic aneurysm, acute aortic syndrome, traumatic aortic injury, and atherosclerosis. Given the nonspecific clinical features, noninvasive imaging is critical in screening, diagnosis, management, and posttherapeutic surveillance. Of the commonly used imaging modalities, including ultrasound, computed tomography, and MR imaging, the final choice often depends on a combination of factors: acuity of clinical presentation, suspected underlying diagnosis, and institutional practice. Further research is needed to identify the potential clinical role and define appropriate use criteria for advanced MR applications such as four-dimenional flow to manage patients with aortic pathologic conditions.

The Role of Multimodality Imaging Approach in Acute Aortic Syndromes: Diagnosis, Complications, and Clinical Management

Acute aortic syndromes are life-threatening conditions with high morbidity and mortality. The principal pathological feature is acute wall damage with possible evolution towards aortic rupture. Accurate and timely diagnosis is mandatory to avoid catastrophic consequences. Indeed, misdiagnosis with other conditions mimicking acute aortic syndromes is associated with premature death. In this view, cardiovascular imaging is necessary for the correct diagnosis and management. Echocardiography, computed tomography, magnetic resonance imaging, and aortography allow for diagnosis, guarantee immediate treatment, and detect associated complications. Multimodality imaging is essential in the diagnostic work-up to confirm or rule out acute aortic syndromes. The aim of this review is to highlight the contemporary evidence on the role of single cardiovascular imaging techniques and multimodality imaging in the diagnosis and management of acute aortic syndromes.

A stable and quantitative method for dimensionality reduction of aortic centerline

Aortic dissection (AD) is a fatal aortic disease with high mortality. Assessing the morphology of the aorta is critical for diagnostic and surgical decisions. Aortic centerline projection methods have been used to evaluate the morphology of the aorta. However, there is a big difference between the current model of primary plane projection (PPP) and the actual shape of individuals, which is not conducive to morphological statistical analysis. Finding a method to compress the three-dimensional information of the aorta into two dimensions is helpful to clinical decision-making. In this paper, the evaluation parameters, including contour length (CL), enclosure area, and the sum of absolute residuals (SAR), were introduced to objectively evaluate the optimal projection plane rather than artificial subjective judgment. Our results showed that the optimal projection plane could be objectively characterized by the three evaluation parameters. As the morphological criterion, SAR is optimal among the three parameters. Compared to the optimal projection plane selected by traditional PPP, our method has better AD discrimination in the analysis of aortic tortuosity, and is conducive to the clinical operation of AD. Thus, it has application prospects for the preprocessing techniques for the geometric morphology analysis of AD.

CT findings of type A acute aortic dissection that did and did not result in prehospital death

The differences between the pathologies of cases of type A acute aortic dissection (AAD) that did and did not result in prehospital death (PHD) have not been fully elucidated.This study aimed to compare the CT findings and clarify the differences between the pathologies of such cases.Ninety four consecutive type A AAD patients between 2010 and 2020 were enrolled in this study. There were 47 males and 47 females (mean age: 69.0 ± 14.4 years). The patients were divided into those that did (n = 25, 27%) and did not (n = 69, 73%) suffer PHD. We retrospectively evaluated the CT or postmortem CT findings of each case and analyzed the relationships between clinical factors (CT findings and clinical characteristics) and PHD using logistic regression analysis.Bloody pericardial effusion (96% vs 35%, P < .0001), bloody pleural effusion (40% vs 1%, P < .0001), and mediastinal hematomas (88% vs 14%, P < .0001) were significantly more common in the PHD group than in the no PHD group.In the multivariate logistic regression analysis, bloody pericardial effusion and lung consolidation were found to be significant risk factors for PHD (odds ratio: 21.29 [95% confidence intervals {CI}: 1.19-248.29] and 13.72 [95% CI: 1.79-105.06], respectively; P = .014 and P  = .012, respectively). AD affecting the abdominal aorta was identified as a significant negative risk factor for PHD (odds ratio: 0.02 [95% CI: 0.01-0.65]; P = .0042).Most PHD due to type A AAD are associated with hemorrhaging. Bleeding into the pericardium and type A AAD confined to the thoracic aorta are significant risk factors for PHD. Secondary respiratory failure might contribute to PHD in such cases.

Approach to Abdominal Imaging in 2022

Abdominal pain represents 5% to 7% of all emergency department presentations. Many patients require imaging for diagnosis, and choosing the appropriate imaging modality is a crucial decision point. Modern medicine offers a fantastic array of options including abdominal radiograph, computed tomography, MRI, and ultrasonography, but the plethora of alternatives can be paralyzing. This article introduces the commonly available modalities, discusses the advantages and disadvantages, and presents current recommendations for commonly diagnosed conditions.

Investigation of Three-dimensional Printing Materials for Printing Aorta Model Replicating Type B Aortic Dissection

AIM

This study aims to determine a printing material that has both elastic property and radiology equivalence close to the real aorta for simulation of endovascular stent-graft repair of aortic dissection.

BACKGROUND

With the rapid development of Three-Dimensional (3D) printing technology, a patient- specific 3D printed model is able to help surgeons to make a better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic Computed Tomography (CT) attenuation.

OBJECTIVE

Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection.

METHODS

A 25-mm length of aorta model was segmented from a patient's image dataset with a diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen. Five reference points with the Region Of Interest (ROI) of 1.77 mm2 were selected at the aortic wall, and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient's aorta and models was performed through a paired-sample t-test to determine if there is any significant difference.

RESULTS

The mean CT attenuation of the aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with the other three materials was significantly lower than that of the original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images without a statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05).

CONCLUSION

Both Visijet CE-NT and Agilus have tensile strength and elongation close to actual patient's tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to the lack of body phantoms in the experiments, further research with the simulation of realistic anatomical body environment should be conducted.

Population-based incidence and outcomes of acute aortic dissection in Japan

AIMS

The population-based incidence and outcomes of acute aortic dissection (AAD) are still unknown because some patients are already dead on arrival, and the accurate diagnosis of AAD is difficult due to the low autopsy rate. We performed a population-based review of all patients with AAD in a well-defined geographical area in Japan between 2016 and 2018.

METHODS AND RESULTS

Data of all patients with AAD at Miyazaki Prefectural Nobeoka Hospital (MPNH), which performs medical care for 120 000 residents, were collected retrospectively. The emergency medical service is dedicated to the transfer of all patients in this area to the MPNH. For all patients who were dead on arrival, the diagnosis of AAD was made by autopsy imaging (AI) using computed tomography. The age-adjusted incidence and mortality per 100 000 population were calculated using the Japanese population distribution model in 2015. The total incidence of AAD was 79 (type A: 64.5%, n = 51). Of those, 60.8% (31/51) of patients with type A and 21.4% (6/28) with type B were dead on arrival and diagnosed by AI. The 30-day mortality rates were 74.5% (38/51) in type A and 25.0% (7/28) in type B. The age-adjusted incidence and mortality of AAD per 100 000 inhabitants were 17.6 (type A: 11.3, type B: 6.2) and 9.9 (type A: 8.4, type B: 1.5), respectively.

CONCLUSIONS

The population-based survey of AAD showed that the age-adjusted incidence of AAD was two-fold higher than in previous reports, and the actual mortality rates were markedly higher due to the high incidence of dead-on-arrival.

Multimodality imaging assessment of bicuspid aortic valve disease, thoracic aortic ectasia, and thoracic aortic aneurysmal disease

Acute aortic syndromes have extremely high mortality rates and those with aortic dilation are at increased risk for these often catastrophic events. Serial monitoring of patients with aortic dilation is critical to determine the appropriate timing of preventative interventions. The thoracic aorta can be imaged and measured using multiple imaging modalities including transthoracic echocardiography, transesophageal echocardiography, multidetector cardiac computed tomography, and magnetic resonance imaging. There has not been agreement on the specific techniques that should be used to measure thoracic aortic dimensions with each imaging modality, leading to potential errors and challenges in comparing changes in measurements over time. It is critical to understand the current recommendations on thoracic aortic measurements for each imaging modality and cardiovascular imaging specialists need to be explicit about the methods that they have used to derive the thoracic aortic measurements. In those at high risk for aortic pathology, such as those with connective tissue diseases or bicuspid aortic valve, a multimodality imaging strategy incorporating echocardiography including three-dimensional measurements along with cardiac computed tomography or magnetic resonance imaging should be used to establish aortic dimensions and for continued monitoring to avoid progression to acute aortic syndromes.

Prescreening and treatment of aortic dissection through an analysis of infinite-dimension data

Background

Aortic dissection (AD) is one of the most catastrophic aortic diseases associated with a high mortality rate. In contrast to the advances in most cardiovascular diseases, both the incidence and in-hospital mortality rate of AD have experienced deviant increases over the past 20 years, highlighting the need for fresh prospects on the prescreening and in-hospital treatment strategies.

Methods

Through two cross-sectional studies, we adopt image recognition techniques to identify pre-disease aortic morphology for prior diagnoses; assuming that AD has occurred, we employ functional data analysis to determine the optimal timing for BP and HR interventions to offer the highest possible survival rate.

Results

Compared with the healthy control group, the aortic centerline is significantly more slumped for the AD group. Further, controlling patients’ blood pressure and heart rate according to the likelihood of adverse events can offer the highest possible survival probability.

Conclusions

The degree of slumpness is introduced to depict aortic morphological changes comprehensively. The morphology-based prediction model is associated with an improvement in the predictive accuracy of the prescreening of AD. The dynamic model reveals that blood pressure and heart rate variations have a strong predictive power for adverse events, confirming this model’s ability to improve AD management.

Supplementary Information

The online version contains supplementary material available at (10.1186/s13040-021-00249-8).

Aortic Dissection and Other Acute Aortic Syndromes: Diagnostic Imaging Findings from Acute to Chronic Longitudinal Progression

Acute aortic dissection is the prototype of acute aortic syndromes (AASs), which include intramural hematoma, limited intimal tear, penetrating atherosclerotic ulcer, traumatic or iatrogenic aortic dissection, and leaking or ruptured aortic aneurysm. The manifestation is usually sudden and catastrophic with acutely severe tearing chest or back pain. However, clinical symptoms do not allow distinction between AAS types and other acute pathologic conditions. Diagnostic imaging is essential to rapidly confirm and accurately diagnose the type, magnitude, and complications of AASs. CT fast acquisition of volumetric datasets has become instrumental in diagnosis, surveillance, and intervention planning. Most critical findings affecting initial intervention and prognosis are obtained at CT, including involvement of the ascending aorta, primary intimal tear location, rupture, malperfusion, size and patency of the false lumen, complexity and extent of the dissection, maximum caliber of the aorta, and progression or postintervention complications. Involvement of the ascending aorta-Stanford type A-has the most rapid lethal complications and requires surgical intervention to affect its morbidity and mortality. Lesions not involving the ascending aorta-Stanford type B-have a lesser rate of complications in the acute phase. During the acute to longitudinal progression, various specific and nonspecific imaging findings are encountered, including pleural and pericardial effusions, fluid collections, progression including aortic enlargement, and postoperative changes that can be discerned at CT. A systematic analysis algorithm is proposed for CT of the entire aorta throughout the continuum of AASs into the chronic and posttreated disease state, which synthesizes and communicates salient findings to all care providers. Online supplemental material is available for this article. ^©RSNA, 2021.

Non-traumatic thoracic aortic emergencies: imaging diagnosis and management

The major component of non-traumatic thoracic aortic emergencies is the acute aortic syndromes. These include acute aortic dissection, intramural haematoma and penetrating atherosclerotic ulcer, grouped together because they are indistinguishable clinically and highly fatal. All three entities involve disruption to the tunica intima and media and may be complicated by rupture, end-organ ischaemia or aneurysmal transformation. Early diagnosis is vital to allow timely and appropriate management. Paired unenhanced and electrocardiogram-gated computed tomography angiography of the chest, extending more distally if required, is recommended for diagnosis. Specific computed tomography features of all three entities are reviewed, with a focus on morphological features associated with complications. Those with type A pathology are usually managed with open surgery because this has a high risk of complication. Patients with uncomplicated type B pathology are usually managed with best medical therapy whereas those with complicated type B pathology are usually offered either surgery or thoracic endovascular aortic repair. The limited evidence regarding the use of thoracic endovascular aortic repair in patients with subacute uncomplicated type B pathology is briefly discussed.

Incidence and characteristics of acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest evaluated by non-contrast computed tomography

Background

The exact epidemiology of acute aortic dissection, including cases of out-of-hospital cardiopulmonary arrest, is unclear. We aimed to investigate the incidence and characteristics of acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest transferred to our institution and validate the related factors to out-of-hospital cardiopulmonary arrest in Stanford type A acute aortic dissection.

Methods

We retrospectively reviewed the acute-phase computed tomography data of patients with out-of-hospital cardiopulmonary arrest who visited our hospital between 1 January 2015 and 31 December 2017.

Results

Among 1011 consecutive patients with out-of-hospital cardiopulmonary arrest, excluding those aged 17 years and younger and exogenous out-of-hospital cardiopulmonary arrest, such as suicide and trauma, 934 underwent computed tomography examination and 71 (7.6%) were diagnosed with acute aortic dissection: 66 with Stanford type A and five with type B acute aortic dissection (out-of-hospital cardiopulmonary arrest group). Seventy-five patients without out-of-hospital cardiopulmonary arrest with Stanford type A acute aortic dissection visited our institution during the same period (non-out-of-hospital cardiopulmonary arrest group). Age, incidence of massive bloody pericardial effusion and massive intrathoracic haemorrhage were significantly higher in the out-of-hospital cardiopulmonary arrest than in the non-out-of-hospital cardiopulmonary arrest group (78 ± 8 years, 72.7% and 24.2% vs. 70 ± 13 years, 26.7% and 1.3%, respectively; all P &lt; 0.01). These variables were independently related to out-of-hospital cardiopulmonary arrest.

Conclusions

There may be more patients with acute aortic dissection with out-of-hospital cardiopulmonary arrest than previously thought. Aortic rupture into the pericardial space or thoracic cavity is the major cause of out-of-hospital cardiopulmonary arrest in these cases. Non-contrast computed tomography can be used to diagnose acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest. Our study is one of a few to evaluate the real circumstances surrounding acute aortic dissection and its epidemiology.

Low correlation between biometric parameters, cardiovascular risk factors and aortic dimensions by computed tomography coronary angiography

To analyze the relationship between aortic measures and biometric parameters in a large cohort of consecutive patients undergoing computed tomography coronary angiography.1170 patients (717 men/453 women) performing computed tomography coronary angiography for coronary evaluation were retrospectively evaluated. Aortic diameters and areas were measured at reproducible anatomic landmarks, perpendicular to the axis of vessel, at the level of the aortic root (AoR), the sinotubular junction (STJ), and the tubular ascending aorta (TAo). Biometric parameters and cardiovascular risk factors were recorded.The average values of AoR, STJ, and TAo were 35.63 ± 5.00 mm, 30.56 ± 4.82 mm, 35.07 ± 5.84 mm. Hypertension was significantly associated with aortic dimensions.Aortic measures were significantly different between men and women (37.56 ± 4.77 mm vs 32.58 ± 3.68 mm for AoR, 31.88 ± 4.84 mm vs 28.47 ± 3.98 mm for STJ and 35.93 ± 5.86 mm vs 33.70 ± 5.54 mm for TAo) (P < .001) and linearly increased with age. Low Spearman correlation coefficients were found and the correlation of TAo diameters with age displayed the highest values (ρ = 0.372 for male and ρ = 0.373 for female, P < .001). Multiple linear regression analysis models were compared by R. The best model used body surface area (BSA) and age as independent variables and TAo diameter as dependent variable (R = 0.29 for AoR; R = 0.21 for STJ, and R = 0.20 for TAo).In conclusion, in our population low correlation between aortic dimensions and biometric parameters highlights the difficulty of identifying normal ranges, as well as issues related to normalization using conventional biometric parameters.

Multidetector Computed Tomography in Traumatic and Nontraumatic Aortic Emergencies: Emphasis on Acute Aortic Syndromes

Aortic emergencies comprise of a list of conditions which are uncommon but are potentially fatal. Prognosis is usually determined by emergent diagnosis and treatment and hence radiology plays a key role in patient management. In this article, we aim to review the various causes of aortic emergencies and the relevant imaging findings placing special emphasis on acute aortic syndromes.

Diagnostic computed tomography in acute interscapular pain

Clinical introductionA man in his 60s with no medical history presented with sudden-onset, severe interscapular pain. He was in circulatory shock with a blood pressure of 65/30 mm Hg, heart rate of 115 beats per minute, respiratory rate of 32 breaths per minute and a room air oxygen saturation of 89%. Examination demonstrated weak peripheral pulses, an elevated jugular venous pressure, faint dual heart sounds, no cardiac murmurs and bilateral lung crepitations. An ECG was recorded which showed a broad QRS (figure 1A). There were no previous ECGs to compare this with. In view of his presentation with acute-onset interscapular pain, CT of the aorta was organised by the emergency department clinicians (figure 1B-D). After the CT result was obtained, the on-call cardiologist was contacted and a bedside echocardiogram performed. This demonstrated severe left ventricular systolic dysfunction with akinesia of the apex and lateral walls. The patient was then transferred to the catheter laboratory for an emergency invasive coronary angiogram.heartjnl;106/2/126/F1F1F1Figure 1ECG and CT images at presentation (A) 12 lead ECG. (B) Contrast enhanced CT aorta - coronal view. (C) Contrast enhanced CT aorta - axial view. (D) CT aorta showing 4 chamber view of the heart. WHAT IS THE MOST LIKELY DIAGNOSIS?: Pulmonary embolism.Aortic dissection.Acute myocardial infarction.Cardiac tamponade.

The use of non-contrast-enhanced MRI to evaluate serial changes in endoleaks after aortic stenting: a case report

Background

Aortic dissection is a life-threatening syndrome that sometimes requires emergency intervention, and endovascular aortic aneurysm repair (EVAR) is a treatment option. Long-term image follow-up is also required for patients after EVAR due to possible complications.

Case presentation

We present the case of a 73-year-old male with underlying chronic renal disease diagnosed with a type A aortic dissection who underwent EVAR. Four-dimensional (three spatial dimensions combined with time) phase-contrast magnetic resonance imaging (4D PC-MRI) was performed during regular follow-up in preference to contrast-enhanced computed tomography or simple MRI while taking his poor renal function into consideration.

Conclusions

We considered this preferable given his issues with renal function.

Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest

PURPOSE

Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting.

METHODS

This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region.

RESULTS

Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care.

CONCLUSIONS

An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.

Role of intraluminal thrombus in abdominal aortic aneurysm ruptures: A hemodynamic point of view

PURPOSE

Intraluminal thrombus (ILTs) are found in most abdominal aortic aneurysms (AAAs) of clinically relevant size; however, the role of ILTs in AAA ruptures remains unclear. This study investigated the role of the presence and thickness of ILTs in AAA ruptures by analyzing the hemodynamic environment in ruptured AAAs (RAAAs).

METHODS

Three-dimensional reconstructions from computed tomography scans were performed, and 13 RAAA cases were categorized into a no-ILT group, a thin-layered ILT group (thickness < 3 mm), and a thick-layered ILT group. The hemodynamic features of the RAAAs were assessed using computational fluid dynamics simulation.

RESULTS

The thin- and thick-layered ILT groups showed significant differences in aneurysm diameters (P < 0.05). The three types of AAAs ruptured at different flow regions, with different hemodynamic features: (a) the no-ILT AAAs ruptured at regions of flow recirculation where velocity and wall shear stresses (WSSs) were close to zero; (b) the thin-layered ILT AAAs ruptured at sites at which the dominant flow impinged the wall; and (c) the thick-layered ILT AAAs ruptured at the border of the dominant flow channel and recirculation zone where the flow velocity and pressure changed dramatically.

CONCLUSIONS

Hemodynamic characteristics influence the rupture mechanisms of particular AAAs differently on the basis of the presence and thickness of ILTs. Recirculation flows and low WSSs may have negative effects by inducing local rupture or positive effects by promoting the formation of thin-layered ILTs. However, eccentrically located thick-layered ILTs may increase the rupture risk of small AAAs because of their location in the sac lumen, which results in chaotic flow patterns and rapid increases in flow resistance.

A low threshold to ECG-gated repeat CTA reduces the risk of false-positive diagnosis of type A dissection in interhospital referrals: a case series study

Background

False-positive diagnosis of acute Stanford type A aortic dissection (AAD) on computed tomography angiography (CTA) is still an issue and may lead to substantial consequences. Given that electrocardiography (ECG)-gated CTA provides greater diagnostic safety, it may be assumed that interhospital referrals with a diagnosis of AAD based on non-ECG-gated pre-referral CTA carry an elevated risk of false-positive diagnosis.

Patients and methods

We reviewed a series of patients in whom a diagnosis of AAD based on non-ECG-gated pre-referral CTA was subsequently proven false by ECG-gated CTA. The artifacts that gave rise to the misdiagnosis, as well as the diagnostic pathways followed and the consequences of false-positive diagnosis were investigated.

Results

In 5 patients, ECG-gated repeat CTA revealed artifacts in the pre-referral scans that had led to false-positive diagnosis and referral for emergent surgery. In the first case, the patient proceeded to surgery. In 4 subsequent cases, ECG-gated CTA was ordered because a false-positive diagnosis was suspected. We found that ECG-gated CTA rather than echocardiography provided sufficient information to rule out AAD in each of these cases. Comparison between pre-referral non-ECG-gated scans and ECG-gated repeat CTA demonstrated the wide range of artifacts that may give rise to a diagnosis of AAD.

Conclusion

Patient condition permitting, the threshold to ECG-gated repeat CTA should be low when doubt arises with regard to a diagnosis of AAD based on non-ECG-gated CTA in interhospital referrals.

Pictorial essay: Computed tomography findings in acute aortic syndromes

Acute aortic emergencies are life-threatening conditions that may require urgent surgical or interventional management. Imaging plays an important role in the diagnosis and planning of the management, and timely intervention helps in reducing mortality and morbidity.

Acute aortic syndromes and aortic emergencies

Acute aortic syndrome (AAS) and emergencies are relatively uncommon but are considered as life threatening, potentially fatal conditions. Different forms of aortic emergencies/AAS are often clinically indiscernible. Prompt and accurate diagnosis of these entities significantly influences prognosis and guides therapy. We aim to elucidate the pertinent role that radiology plays in the management of acute aortic diseases, with contrast-enhanced computed tomography angiography (CTA) being the most rapid and robust imaging technique.

Spectrum of Abdominal Aortic Disease in a Tertiary Health Care Setup: MDCT Based Observational Study

INTRODUCTION

Abdominal aortic disease is an important cause of clinical disability that requires early detection by imaging methods for prompt and effective management. Understanding regional disease pattern and prevalence has a bearing on healthcare management and resource planning. Non-invasive, conclusive imaging strategy plays an important role in the detection of disease. Multi-Detector Computed Tomography (MDCT) with its technological developments provides affordable, accurate and comprehensive imaging solution.

AIM

To evaluate regional demography of abdominal aortic disease spectrum detected using MDCT imaging data in a tertiary hospital.

MATERIALS AND METHODS

A descriptive study was conducted based on MDCT imaging data of patients who were investigated with clinical diagnosis of abdominal aortic disease, from March 2008-2010, over a period of 24 months. Patients were examined with the contrast-enhanced MDCT examination. Morphological diagnosis of the aortic disease was based on changes in relative aortic caliber, luminal irregularity, presence of wall calcification, dissection or thrombus and evidence of major branch occlusion. Patients were categorized into four groups based on imaging findings. MDCT information and associated clinical parameters were examined and correlated to management of patient. Descriptive statistical data, namely mean, standard deviation and frequency of disease were evaluated.

RESULTS

A total of 90 out of 210 patients (43%) were detected with the abdominal aortic abnormality defined by imaging criteria. Group I, comprising of patients with atherosclerosis -including those with complications, constituted 65.5% of the patients. Group II represented patients with aneurysms (45.5%). Group III, consisting of 32.2% of the patients, contained those with dissections. The rest of the patients, including patients with aorto-arteritis, were classified as group IV. Eight patients with aneurysm and one patient with aorto-arteritis were considered for surgical treatment. Ten patients with dissection underwent endovascular procedure. Rest of the patients was managed conservatively.

CONCLUSION

Aortic disease was observed in 43% of investigated patients. Atherosclerosis with and without aortic aneurysm constituted the largest group. MDCT provided comprehensive information about the lesion and associated complications. In view of the wider availability and desired imaging qualities, MDCT provided optimal information for diagnosis and management of aortic pathology. Majority of our patients (90%) were treated conservatively.

Prevalence of Type A Acute Aortic Dissection in Patients With Out-Of-Hospital Cardiopulmonary Arrest

Postmortem computed tomography (PMCT) has been recently reported to be useful for detecting causes of death in the emergency department. In this study, the incidence and causes of death of type A acute aortic dissection (AAD) were investigated in patients who experienced out-of-hospital cardiopulmonary arrest (OHCPA) using PMCT. PMCT or enhanced computed tomography was performed in 311 of 528 consecutive patients experiencing OHCPA. A total of 23 (7%) of 311 patients were diagnosed with type A AAD based on clinical courses and CT findings. Eighteen consecutive patients who did not experience OHCPA were diagnosed with type A AAD during the same period. Pre-hospital death was observed in 21 (51%) of 41 patients with type A AAD. Bloody pericardial effusion was observed more frequently in patients who experienced OHCPA with type A AAD than in those who did not experience OHCPA with type A AAD (91% vs 28%, respectively; p <0.05). In conclusion, the incidence of type A AAD was common (7%) in patients who experienced OHCPA, with a high rate of pre-hospital death. Aortic rupture to the intrapericardial space was considered the major cause of death in patients who experienced OHCPA with type A AAD.

Aortic Dissection as a Cause of Pulsus Bisferiens: A Case Report and Review

We present a case of a 62-year-old woman who developed an aortic dissection after aortic valve replacement for aortic stenosis and supracoronary replacement of the ascending aorta for aneurysmal dilation. Dynamic compression of the distal aorta by the dissection flap was identified with the detection of abnormal continuous wave Doppler signals heard while performing ankle-brachial indices. Duplex ultrasound (US) and Doppler spectral waveforms confirmed dynamic compression of the distal aorta with each cardiac cycle. We review some of the characteristics of continuous wave Doppler signals, specifically discussing the distinguishing characteristics of pulsus bisferiens, and the use of duplex US in imaging the distal aorta.

Type A aortic dissection presenting as superior vena cava syndrome

A 51-year-old man presented with a 5-day history of progressive facial swelling, sensation of head fullness, increasing shortness of breath and paroxysmal nocturnal dyspnea. He denied chest pain, syncope or presyncope. Pastmedical history included mechanical aortic valve replacement 7 years prior and atrial fibrillation treated with warfarin. A clinical diagnosis of acute superior vena cava (SVC) syndrome was made. Portable chest radiograph showed a widened superior mediastinum. Computed tomography scan of the thorax demonstrated a large type A aortic dissection almost completely effacing the SVC. Acute type A aortic dissection (AD) is an emergency requiring prompt diagnosis and treatment. Patients typically present with acute onset of chest and/or back pain, classically described as “ripping” or “tearing.” SVC syndrome is rarely, if ever, mentioned as a presentation, as it is usually due to more chronic conditions. This case illustrates a rare incidence of type A AD actually presenting as SVC syndrome.

CT angiography in the diagnosis of cardiovascular disease: a transformation in cardiovascular CT practice

Computed tomography (CT) angiography represents the most important technical development in CT imaging and it has challenged invasive angiography in the diagnostic evaluation of cardiovascular abnormalities. Over the last decades, technological evolution in CT imaging has enabled CT angiography to become a first-line imaging modality in the diagnosis of cardiovascular disease. This review provides an overview of the diagnostic applications of CT angiography (CTA) in cardiovascular disease, with a focus on selected clinical challenges in some common cardiovascular abnormalities, which include abdominal aortic aneurysm (AAA), aortic dissection, pulmonary embolism (PE) and coronary artery disease. An evidence-based review is conducted to demonstrate how CT angiography has changed our approach in the diagnosis and management of cardiovascular disease. Radiation dose reduction strategies are also discussed to show how CT angiography can be performed in a low-dose protocol in the current clinical practice.

The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome

The term "acute aortic syndrome" (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions.

The ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography

BACKGROUND

Aortic dissection is a lift-threatening medical emergency associated with high rates of morbidity and mortality. The incidence rate of aortic dissection is estimated at 5 to 30 per 1 million people per year. The prompt and correct diagnosis of aortic dissection is critical. This study was to compare the ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography and conventional dual-source CT angiography.

METHODS

A total of 110 consecutive patients with suspected aortic dissection and other aortic disorders were randomly divided into two groups. Group A underwent traditional scan mode and Group B underwent high-pitch dual-source CT scan mode. The image quality and radiation dose of two groups were compared.

RESULTS

Close interobserver agreement was found for image quality scores (κ = 0.87). The image quality of ascending aorta was significantly better in the high-pitch group than in the conventional group (2.78 ± 0.46 vs 1.57 ± 0.43, P < 0.001). There was no significant difference of the CT attenuation values, the aortic image noise and SNR between two groups. The mean radiation dose of high-pitch group was also significantly lower than that of conventional group (2.7 ± 0.6 mSv vs. 3.9 ± 0.9 mSv, P < 0.001).

CONCLUSIONS

High-pitch dual-source CT angiography of the whole aorta can provide motion-artifact-free imaging of the ascending aorta at a low radiation dose compared to conventional protocol.

Pulmonary multislice computed tomography findings in acute aortic dissection

OBJECTIVE

To document the type and incidence of pulmonary multislice computed tomography (CT) findings at presentation in patients with acute aortic dissection.

MATERIALS AND METHODS

Multidetector CT scans of 36 patients with a diagnosis of acute aortic dissection or intramural hematoma were retrospectively reviewed.

RESULTS

Pleural effusion, dependent stasis, mosaic attenuation, interlobular septal thickening, thickening of the peribronchovascular interstitium, vascular enlargement, compression atelectasis were common findings. Additionally air trapping, emphysema, consolidation, nodules, bronchiectasis or scarring were also noted.

CONCLUSIONS

Various pulmonary imaging findings may accompany acute aortic dissection. These findings and their clinical significance should be further investigated.

A Comparative Study of Imaging Techniques in Aortic Dissection, DeBakey Type I: Intraoperative Live Three-Dimensional Epicardial Echocardiography, Multiplane Transesophageal Echocardiography, and Multislice Computed Tomography

OBJECTIVE

: To compare the accuracy of intraoperative live 3-dimensional epicardial echocardiography, multiplane transesophageal echocardiography (TEE), and multislice computed tomography (MSCT) imaging in the detection of thoracic aortic dissection, site of intimal tear, and involvement of arch vessel.

METHODS

: Of 24 patients studied from October 2003 to September 2004, 12 had aortic dissection. They were examined preoperatively with contrast material-enhanced MSCT and multiplane TEE. Intraoperative live 3-dimensional epicardial echocardiographic evaluation of the ascending aorta and arch was performed. Imaging results in terms of detection of aortic dissection, site of intimal tear, and involvement of coronary arteries and arch vessels were confirmed at intraoperative exploration by the operating surgeon as the reference standard.

RESULTS

: Sensitivity in the detection of thoracic aortic dissection was 100% for all techniques. Specificity was 92%, 92%, and 100% for live 3-dimensional epicardial echocardiography, multiplane TEE, and MSCT imaging, respectively. In the assessment of aortic arch vessel involvement, sensitivity was 92%, 58%, and 92%, and specificity was 75%, 50%, and 83%, respectively. For the detection of the site of intimal tear, sensitivity was 92%,92%, and 58%, and specificity was 83%,75%, and 50%, respectively.

CONCLUSION

: Intraoperative live 3-dimensional epicardial echocardiography is as valuable as multiplane TEE and MSCT imaging in the detection of thoracic aortic dissection. In the assessment of the aortic arch vessel involvement, MSCT and live 3-dimensional epicardial echocardiography are superior (P < 0.05), whereas live 3-dimensional epicardial echocardiography and TEE are superior in detection of site of intimal tear (P < 0.05).

Acute aortic syndromes: a second look at dual-phase CT

OBJECTIVE

The purpose of this article is to assess the diagnostic performance of the unenhanced and contrast-enhanced phases separately in patients imaged with CT for suspected acute aortic syndromes.

MATERIALS AND METHODS

All adults (n = 2868) presenting to our emergency department from January 1, 2006, through August 1, 2010, who underwent unenhanced and contrast-enhanced CT of the chest and abdomen for suspected acute aortic syndrome were retrospectively identified. Forty-five patients with acute aortic syndrome and 45 healthy control subjects comprised the study population (55 women; mean age, 61 ± 16 years). Unenhanced followed by contrast-enhanced CT angiography (CTA) images were reviewed. Contrast-enhanced CTA examinations of case patients and control subjects with isolated intramural hematoma were reviewed. Radiation exposure was estimated by CT dose-length product.

RESULTS

Forty-five patients had one or more CT findings of acute aortic syndrome: aortic dissection (n = 32), intramural hematoma (n = 27), aortic rupture (n = 10), impending rupture (n = 4), and penetrating atherosclerotic ulcer (n = 2). Unenhanced CT was 89% (40/45) sensitive and 100% (45/45) specific for acute aortic syndrome. Unenhanced CT was 94% (17/18) and 71% (10/14) sensitive for type A and type B dissection, respectively (p = 0.142). Contrast-enhanced CTA was 100% (8/8) sensitive for isolated intramural hematoma. Mean radiation effective dose was 43 ± 20 mSv.

CONCLUSION

Unenhanced CT performed well in detection of acute aortic syndrome treated surgically, although its performance does not support its use in place of contrast-enhanced CTA. Unenhanced CT may be a reasonable first examination for rapid triage when IV contrast is contraindicated. Contrast-enhanced CTA was highly sensitive for intramural hematoma, suggesting that unenhanced imaging may not always be needed. Acute aortic syndrome imaging protocols should be optimized to reduce radiation dose.

Diagnostic accuracy and clinical outcomes of ECG-gated, whole chest CT in the emergency department

PURPOSE

The purpose of this study was to assess the diagnostic accuracy and one year prognosis of whole chest, "multiple rule out" CT for coronary artery disease (CAD) in Emergency Department patients.

METHODS AND FINDINGS

One hundred and two Emergency Department patients at low to intermediate risk of acute coronary syndrome (ACS), pulmonary embolism and/or acute aortic syndrome underwent a research 64 channel ECG-gated, whole chest CT and a standard of care evaluation. Patients were classified with obstructive CAD with either a coronary CT stenosis greater than 50% or a non-evaluable coronary segment. SOC and 3 month follow up data were used to determine an adjudicated clinical diagnosis. The diagnostic ability of obstructive CAD on CT to identify clinical diagnoses was determined. Patients were followed up for 1 year for cardiac events. Seven (7%) patients were diagnosed with ACS. CT sensitivity to detect obstructive CAD in ACS patients was 100% (95% CI 65%, 100%), negative predictive value 100% (96%, 100%), specificity 88% (80%, 94%), and positive predictive value 39% (17%, 64%). Pulmonary embolism and acute aortic syndrome were not identified in any patients. No cardiac events occurred in patients without obstructive CAD over 1 year.

CONCLUSIONS

Whole chest CT has high sensitivity and negative predictive value for ACS with excellent one year prognosis in patients without obstructive CAD on CT. The frequency of pulmonary embolism or acute aortic syndrome and the higher radiation dose suggest whole chest CT should be limited to select patients. ClinicalTrials.org #: NCT00855231.

Persistent type B aortic dissection treatment by renal artery reentry stent grafting as an alternative to open surgery

Type B aortic dissections complicated by pain, malperfusion, or aneurysm expansion mandate surgical intervention. Success of this therapy is predicated on exclusion and thrombosis of the false lumen of the aneurysm. This report presents a case in which cessation of flow was achieved using a covered stent graft to close a renal reentry tear after a previous closing and overstenting of the main tear. This approach may provide a helpful adjunct to the endovascular treatment of complicated type B aortic dissections.

Diagnostic errors in the evaluation of nontraumatic aortic emergencies

Nontraumatic aortic emergencies (NTAE) are a complex and dynamic group of serious, potentially fatal conditions affecting the aorta. These entities most often present in the emergency department setting, and include aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, as well as aortic rupture and impending rupture. The radiologist plays a critical role in prompt diagnosis and evaluation since presenting signs and symptoms are often nonspecific. This article focuses on the potential sources of error in the imaging evaluation of patients presenting with NTAE.

Analysis of intimal extent and predictors of renal atrophy in patients with aortic dissection

BACKGROUND

The intimal flap of aortic dissection may extend to the abdominal branches and probably lead to malperfusion syndrome. Renal malperfusion and renal atrophy are significantly related to patient outcomes.

PURPOSE

To study the extent of the intimal flap and predisposing factors for renal atrophy in patients with aortic dissection.

MATERIAL AND METHODS

From January 2001 to June 2008, 176 (137 men, aged 21-86 years, mean 51.9 years) of 225 subjects with aortic dissection and computed tomography (CT) met the inclusion criteria for this study. Of these 176 patients, 35 (19.9%) developed unilateral renal atrophy. A review of the CT was conducted to classify aortic branch vessel perfusion into three types: type 1, in which the branch vessels are perfused exclusively from the true lumen; type 2, in which the branches are perfused from both the true and false lumens; and type 3, in which the branches are perfused exclusively from the false lumen. Variables including age, gender, type of aortic dissection, type of perfusion of the abdominal branches, and the presence of thrombi in the false lumen were analyzed to determine whether these factors were related to the left or right side and global or focal renal atrophy.

RESULTS

Of 880 abdominal branches in 176 patients, 622 (70.7%) were classed as perfusion type 1, 50 (5.7%) as type 2, and 208 (23.6%) as type 3. Type 3 perfusion was most commonly observed in the left renal artery, at a frequency of 31.7% (66/208). Partial thrombosis in the false lumen above the level of the renal arteries was seen in 68.8% of patients; such thrombi and type 3 perfusion of the renal artery were significantly related to renal atrophy. The laterality (left or right) and extent (global or focal) of renal atrophy were not related to age, gender, type of aortic dissection, or perfusion type.

CONCLUSION

Type 3 perfusion is most frequent in the left renal artery, and such perfusion and partial thrombi in the false lumen above the renal arteries are significantly related to the development of renal atrophy.