Role of computed tomography and magnetic resonance imaging in assessment of acute aortic syndromes

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.

Spontaneous Rupture of Abdominal Aorta after Seizure in a 23-Year-Old Woman: A Case Report

Spontaneous non-aneurysmal aortic rupture is a rare and life threatening clinical entity. A 23-year-old female patient who visited a nearby hospital due to intractable seizure was transferred to our hospital with the impression of hypotension and decreased level of haemoglobin. She had a history of seizure attacks once a month. However, in the 2 weeks before presentation, the frequency of seizure attacks had increased to 2 to 3 times a day. An abdominal-pelvic computed tomogram scan showed extravasation of contrast from the abdominal aorta at L3 level. An emergency laparotomy revealed a 0.3 cm diameter tear in the posterior wall of the aorta, superior to the iliac bifurcation. We discuss the mechanism of spontaneous aortic rupture and the possibility of aortic rupture related to seizure attacks. (Hong Kong j.emerg.med. 2014;21:103-106)

Lumican as a novel potential clinical indicator for acute aortic dissection: A comparative study, based on multi-slice computed tomography angiography

The aim of the present study was to investigate the association between serum lumican levels and acute aortic dissection (AAD) severity. A total of 82 patients with chest or back pain and 30 healthy volunteers were recruited. Among the patients, there were 70 cases of AAD and 12 cases of intramural hematoma (IMH). AAD severity was determined using multi-slice computed tomography angiography (MSCTA). Serum was collected from the patients upon admission, and lumican levels were detected using an enzyme-linked immunosorbent assay. In addition, correlation analyses were conducted between lumican levels and AAD severity by designing a 'SCORE X, RANGE Y' system to measure the number of affected vital arteries and vertical range of false lumen, based on the MSCTA. Lumican levels differed significantly among the AAD patients (2.32±4.29 ng/ml), IMH patients (0.72±0.32 ng/ml) and healthy volunteers (0.85±0.53 ng/ml; P=0.003). In the AAD patients presenting within 12-72 h of symptom onset, the Spearman's rho correlation coefficient between lumican and SCORE or RANGE was 0.373 (P=0.046) and 0.468 (P=0.010), respectively. The present results suggest that lumican may be a potential marker for aiding the diagnosis and screening for AAD, and may be used to predict the severity of AAD.

Cardiac CT angiography beyond the coronary arteries: what radiologists need to know and why they need to know it

OBJECTIVE

With current state-of-the-art CT combining fast scanning times and high spatial resolution, anatomy beyond the coronary arteries is well visualized and may lead to discovery of abnormalities. The purpose of this article is to provide a strategy for radiologists to recognize important extracoronary cardiac CT angiography (CTA) findings.

CONCLUSION

A systemic approach to cardiac CTA by anatomic location and attention to key CT features are critical to identify and properly characterize important extracoronary cardiac abnormalities.

Treatment patterns and their outcomes of acute aortic intramural hematoma in real world: multicenter registry for aortic intramural hematoma

Background

Intramural hematoma of the aorta (IMH), a variant of classic aortic dissection, shows very dynamic process in the early phase. The aim of this study is to evaluate clinical outcomes of patients with acute aortic IMH from real world registry data.

Methods

We analyzed 165 consecutive patients with acute IMH from five medical centers in Korea. All patients were divided into two groups; type A (n = 61, 37.0%) and type B (n = 104, 63.0%) according to the Stanford classification. Clinical outcomes and morphological evolution by CT were analyzed for 2 years.

Results

Most of the patients (77.0% of type A and 99.0% of type B, P < 0.001) were treated medically during their initial hospitalization. There were no significant differences in in-hospital mortality (4.9% vs. 2.9%, P = 0.671) and 2-year mortality (13.1% vs. 11.5%, P = 0.765) between two groups. During the 2-year follow up period, progression to aortic dissection (18.0% vs. 6.7%, P = 0.037) and surgical treatment (29.5% vs. 2.9%, P < 0.001) were higher in type A. For the type A patients, there were no significant difference in in-hospital mortality (7.1% of surgery vs. 4.3% of medical, P = 0.428) and 2-year mortality (7.1% of surgery vs. 14.9% of medical, P = 0.450) in terms of initial treatment strategy.

Conclusion

For real world practice in Korea, most of IMH patients were treated medically at presentation and showed favorable outcomes. Thus, even in type A acute IMH, early medical treatment with alternative surgical conversion for selected, complicated cases would be a favorable treatment option.

MDCT in diagnosing acute aortic syndromes: reviewing common and less common CT findings

Nontraumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. In this context, multidetector computed tomography (MDCT) is the gold standard due to its intrinsic diagnostic value; its performance approaches 100% sensitivity and specificity, and it is accepted as a first-line modality for suspected acute aortic disease. MDCT allows early recognition and characterisation of acute aortic syndromes as well as the presence of any associated complications - findings that are essential for optimising treatment and improving clinical outcomes. Although classic CT findings have long been known, other unusual signs are continually reported in the medical literature. We reviewed the classic and less common CT findings, correlating them with pathophysiology, timing and management options, to achieve a definite and timely diagnostic and therapeutic definition.

Diagnosis and management of Marfan syndrome

Marfan syndrome (MFS) is a relatively common inherited connective tissue disorder with significant morbidity and mortality. Diagnosis of this syndrome can be difficult, as many of the findings of MFS are present in other syndromes, as well as in the general population. MFS is diagnosed using the Ghent criteria, a group of clinical findings that are specific for MFS. Children and adolescents can pose diagnostic dilemmas as the stigmata of MFS are not present at birth but can evolve through adulthood. Current treatment for MFS is limited to strict blood pressure control and careful selection of physical activity. Aggressive screening and early management could significantly improve the quality of life for these patients.

Intramural haematoma of the thoracic aorta: who's to be alerted the cardiologist or the cardiac surgeon?

This review article is written so as to present the pathophysiology, the symptomatology and the ways of diagnosis and treatment of a rather rare aortic disease called Intra-Mural Haematoma (IMH). Intramural haematoma is a quite uncommon but potentially lethal aortic disease that can strike as a primary occurrence in hypertensive and atherosclerotic patients to whom there is spontaneous bleeding from vasa vasorum into the aortic wall (media) or less frequently, as the evolution of a penetrating atherosclerotic ulcer (PAU). IMH displays a typical of dissection progress, and could be considered as a precursor of classic aortic dissection. IMH enfeebles the aortic wall and may progress to either outward rupture of the aorta or inward disruption of the intima layer, which ultimately results in aortic dissection. Chest and back acute penetrating pain is the most commonly noticed symptom at patients with IMH. Apart from a transesophageal echocardiography (TEE), a tomographic imaging such as a chest computed tomography (CT), a magnetic resonance (MRI) and most lately a multy detector computed tomography (MDCT) can ensure a quick and accurate diagnosis of IMH. Similar to type A and B aortic dissection, surgery is indicated at patients with type-A IMH, as well as at patients with a persistent and/or recurrent pain. For any other patient (with type-B IMH without an incessant pain and/or without complications), medical treatment is suggested, as applied in the case of aortic dissection. The outcome of IMH in ascending aorta (type A) appears favourable after immediate (emergent or urgent) surgical intervention, but according to international bibliography patients with IMH of the descending aorta (type B) show similar mortality rates to those being subjected to conservative medical or surgical treatment. Endovascular surgery and stent-graft placement is currently indicated in type B IMH.

The importance of multidetector computed tomography in the vascular imaging

A több detektorsoros spirál-CT-berendezések és a hozzájuk tartozó speciális rekonstrukciós szoftverek bevezetése lehetővé tette az erek jó minőségű CT-vizsgálatát. Cél és módszerek: A szerzők ismertetik a CT-angiográfiai vizsgálatok elvét, technikáját, amelyet az elmúlt három évben közel 700 saját betegükön végzett vizsgálataik eredményeivel, tapasztalataival egészítenek ki. Bemutatják a CT-angiográfia jelentőségét, valamint annak más vascularis képalkotó eljárások helyett vagy melletti alkalmazhatóságát. Következtetések: A CT-angiográfia gyors, noninvazív vizsgálati módszer, amellyel – önmagában vagy más vizsgálattal kiegészítve – pontos diagnózis állítható fel.

Evaluation of acute coronary syndromes by cardiac magnetic resonance imaging

The use of cardiovascular magnetic resonance (CMR) imaging for the evaluation of patients with acute chest pain and acute coronary syndromes has great potential. The strength of CMR relies on its ability to provide information on anatomy, physiology, and function in a single scanning session in a noninvasive manner without the need for iodinated contrast, radiation, or the need to undergo invasive procedures. Specifically, with regard to imaging patients with acute chest pain and/or myocardial infarction (MI), CMR has the ability to qualitatively and quantitatively evaluate global and regional right and left ventricular systolic functions, myocardial edema, myocardial perfusion, and myocardial infarct size and transmurality/viability. This review will focus on CMR imaging for the following applications: (1) imaging for the evaluation of ventricular function and infarct size in patients with acute chest pain and/or acute MI, (2) for triage and prognosis of patients presenting to the emergency department with acute chest pain, (3) for evaluating patients after sustaining an acute MI, and (4) for stem cell research.

MR Imaging of the Aorta

Recent advances in noninvasive imaging methods, such as CT and MR imaging, have replaced most of invasive angiographic procedures in the diagnosis of acquired aortic disease, decreasing the cost and morbidity of diagnosis. This article reviews and illustrates present MR imaging methods for evaluation of the aorta. Common diseases of the aorta also are discussed with a focus on their unique morphologic and functional features and characteristic MR imaging findings. Knowledge of pathologic conditions of common aortic diseases and proper MR imaging techniques enables accurate and time-efficient aortic evaluation.

Intramural Hematoma and Penetrating Atherosclerotic Ulcer of the Aorta

Intramural hematoma and penetrating aortic ulcer are uncommon but potentially lethal thoracic aortic pathologies. Despite incomplete understanding of their natural history, they have emerged as anatomically appealing targets of endovascular therapy. Appropriate application of these technologies, however, must be predicated on an understanding of the fate of these lesions left untreated, and predictors of their misbehavior. We briefly review the current understanding of these entities.

In Vivo Identification of Complicated Upper Thoracic Aorta and Arch Vessel Plaque by MR Direct Thrombus Imaging in Patients Investigated for Cerebrovascular Disease

OBJECTIVE

The objective of this article was to assess the feasibility of MR direct thrombus imaging (MRDTI) to evaluate the prevalence and location of complicated upper thoracic aortic and arch vessel plaque in patients referred for evaluation of cerebrovascular disease.

SUBJECTS AND METHODS

Patients referred for investigation of cerebrovascular disease by MRI were enrolled. Reasons for referral included transient ischemic attack/amaurosis fugax, acute infarct, remote infarct, or asymptomatic carotid disease. Of the 348 patients initially scanned, 17 were excluded from the analysis. The final patient population included 331 patients (199 men, 132 women; mean age, 67.7 years). Patients were scanned using MRDTI, a 3D, T1-weighted, fat-suppressed spoiled gradient echo that exploits the T1 shortening effects of methemoglobin, directly visualizing hemorrhage/thrombus in the vessel wall, thus identifying complicated plaque. Complicated plaque was defined as a high signal within the atherosclerotic plaque at least twice the signal intensity of muscle.

RESULTS

Forty-three of 331 patients (13%) had complicated upper thoracic aortic atherosclerotic disease, arch vessel atherosclerotic disease, or both. The upper thoracic aorta was involved in 36 of 43 patients (83.7%), and the left subclavian artery was involved in 14 of 43 patients (32.6%). Both the right subclavian artery and the brachiocephalic artery were involved in one of 43 patients (2.3%). Complicated carotid plaque was seen in 25 of 43 patients (58.1%).

CONCLUSION

MRDTI can be applied in the detection of complicated plaque in the upper thoracic aorta and arch vessels. Complicated plaque was identified in 13% of the patient population. The upper thoracic aorta was the most common site involved. This technique could be useful for the screening of asymptomatic at-risk patients.

Acute aortic syndrome: pathology and therapeutic strategies

Acute aortic syndrome (AAS) describes the acute presentation of patients with characteristic "aortic pain" caused by one of several life threatening thoracic aortic pathologies. These include aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer, aneurysmal leak, and traumatic transection. AAS heralds imminent aortic rupture. Highlighting acute aortic pathology as an AAS is therefore important to encourage prompt recognition of this condition and avoid diagnostic delays. The management of AAS remains a therapeutic challenge. The traditional surgical approach to acute "type B" (descending thoracic) aortic pathology is unsatisfactory with high morbidity and mortality. Endovascular aortic stent grafts now represent an alternative minimally invasive approach in these patients who are often poor surgical candidates. Studies show endovascular repair to be technically feasible with fewer complications. This review discusses AAS pathology and in particular assesses the current role for endovascular aortic repair in its treatment.

Suspected aortic dissection and other aortic disorders: multi-detector row CT in 373 cases in the emergency setting

PURPOSE

To retrospectively review the authors' experience with multi-detector row computed tomography (CT) for detection of aortic dissection in the emergency setting.

MATERIALS AND METHODS

The investigation was institutional review board approved, did not require informed patient consent, and was HIPAA compliant. In 373 clinical evaluations in the emergency setting, 365 patients suspected of having aortic dissection and/or other aortic disorders underwent multidetector CT. Criteria for acute aortic disorder were confirmed by using surgical and pathologic diagnoses or findings at clinical follow-up and any subsequent imaging as the reference standard. Positive cases were characterized according to type of disorder interpreted. Resulting sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by using two-way contingency tables. All cases found to be negative for acute aortic disorders were grouped according to alternative CT findings.

RESULTS

Sixty-seven (18.0%) of the 373 cases were interpreted as positive for acute aortic disorder. One hundred twelve acute aortic disorders were identified in these 67 cases: 23 acute aortic dissections, 14 acute aortic intramural hematomas, 20 acute penetrating aortic ulcers, 44 new or enlarging aortic aneurysms, and 11 acute aortic ruptures. Three hundred five (81.8%) cases were interpreted as negative for acute aortic disorder. In 48 negative cases, multidetector CT depicted alternative findings that accounted for the clinical presentation. Of these, three included both acute aortic disorders and alternative findings, and 45 included only alternative findings. One (0.3%) case was indeterminate for acute aortic disorder. Overall, 112 findings were interpreted as positive for acute aortic disorder, an alternative finding, or both at CT. No interpretations were false-positive, one was false-negative, 67 were true-positive, and 304 were true-negative. Sensitivity, specificity, PPV, NPV, and accuracy were 99% (67 of 68), 100% (304 of 304), 100% (67 of 67), 99.7% (304 of 305), and 99.5% (371 of 373), respectively.

CONCLUSION

The positivity rate for acute aortic dissection or other acute aortic disorder in 373 cases examined at multi-detector row CT was 18.0%.

Acute Descending Aortic Dissections: Management of Visceral, Spinal Cord, and Extremity Malperfusion

Acute descending aortic dissection is considered the most catastrophic event affecting the aorta and occurs two to three times more often than rupture of abdominal aortic aneurysms. The therapeutic aim in treating acute dissection is not only directed at the prevention of aneurysmal development and rupture but also to prevent and treat complications such as malperfusion syndrome. According to Lauterbach and coworkers patients with symptomatic malperfusion syndromes have a 51% mortality rate compared with a 29% mortality rate in patients who do not. The surgical in-hospital mortality rate in patients with mesenteric or peripheral vascular ischemic complications may be as high as 89%. Despite an improvement in diagnosing dissections and malperfusion syndromes, and despite improved operative techniques and a better understanding of the significance of perioperative care, the surgical mortality rate can be as high as 50%. Endovascular techniques are constantly evolving that provide an alternative to open procedures. The goal of this article was to review the pathogenesis of malperfusion syndromes in aortic dissection, discuss the current modalities to treat malperfusion of the spinal cord, viscera, and extremities, and examine the results of the treatments used today.

Five cases of non-typhoidal Salmonella endovascular infection

The incidence of human non-typhoidal Salmonella (NTS) infection has increased in many countries. Endovascular infection is one of the most serious forms of extraintestinal infection. Five patients with NTS endovascular infection treated at Middlemore Hospital, Auckland, New Zealand, are presented here. All persons with NTS bacteraemia who are older than 50 years and have a risk of atherosclerosis should be evaluated for possible endovascular infection.

Approach to the dilated aortic root

PURPOSE OF REVIEW

The dilated aortic root is often completely asymptomatic and found incidentally on routine imaging studies such as chest radiograph, echocardiography, chest computed tomography, or magnetic resonance imaging. The dilated aortic root may be associated with underlying aortic valve abnormalities as seen with bicuspid aortic valve. It may also lead to the awareness of important underlying connective tissue disorders like the Marfan syndrome. It is imperative that the dilated aortic root be observed carefully over time with serial imaging studies and that timely resection of the aneurysm be carried out before catastrophic complications such as aortic dissection, aortic rupture, or congestive heart failure from aortic insufficiency occur.

RECENT FINDINGS

In recent years, the advent of molecular genetics has heightened awareness of familial aortic disease such as the Marfan syndrome, bicuspid aortic valve disease, and hereditary aortic aneurysm and dissection. In addition to hypertension and inflammatory aortic disease, these hereditary aortopathies are important to consider in the evaluation of patients with a dilated aorta and have implications for screening of the relatives of the patient with aortic aneurysm.

SUMMARY

Because there is often uncertainty regarding the dilated aortic root, this review will summarize the approach to diagnosis, evaluation, and management of aortic root aneurysms. Clinical features, diagnostic approaches, screening of relatives, and long term follow-up will be highlighted.

Computed tomography assessment of thoracic aortic pathology

Computed tomography technology has improved dramatically in the past decade and now constitutes the backbone of preoperative evaluation for aortic disease. Image acquisition is accomplished with multi-row detectors, and coupled with new reconstruction algorithms provide clinicians with high-resolution images that can be visualized in synch with the cardiac cycle, or as complex three-dimensional renditions of in vivo anatomy. Knowledge regarding the means of data acquisition, reconstruction algorithms, and modes of interpretation are critical for the optimal assessment of aortic disease. These issues are increasingly important as endovascular therapy becomes more commonplace for the treatment of thoracic aortic lesions.