CT angiography of acute aortic syndrome in patients with chronic kidney disease

The term acute aortic syndrome (AAS) refers to a range of different entities, including dissection, intramural haematoma and penetrating atherosclerotic ulcer. Patients with chronic renal disease and particularly those with dominant polycystic kidney disease are susceptible to this pathology, given the underlying renal arteriopathy and hypertension. Imaging plays a crucial role in diagnosing, grading and guiding management of these patients, with computed tomography angiography (CTA) being on the frontline. Albeit of overlapping of imaging findings between these conditions, specific imaging characteristics help discriminate and guide treatment. Given the nephrotoxic contrast agent involved, tailored CTA protocols or alternative imaging modalities such as MRI or US are necessary in this patient population. This review article discusses the main imaging findings of entities found in the spectrum of AAS, as well as the appropriate use and protocol of imaging modalities, focusing on the appropriate use of nephrotoxic contrast agents, the preservation of renal function and maintenance of optimal diagnostic accuracy.

CT diagnosis and destiny of acute aortic intramural hematoma

Acute aortic intramural hematoma (IMH) is a relatively uncommon but potentially life-threatening aortic disease that can occur primarily in hypertensive and atherosclerotic patients. The course of IMH varies widely, with the condition either regressing, remaining stable, or progressing until it leads to outward rupture or intimal layer disruption, eventually resulting in overt aortic dissection. Therefore, poor prognostic computed tomography (CT) features must be promptly recognized and reported by the radiologist. In emergency departments, readily accessible non-invasive CT angiography is crucial for achieving a rapid and accurate diagnosis essential for appropriate management. For Type A and B aortic dissection, surgery is typically recommended in Western countries for patients with Stanford Type A IMH and those experiencing irrepressible pain. For Stanford Type B IMH patients without complications or incessant pain, medical treatment is suggested but with imaging follow-up. In complicated Stanford Type B situations, thoracic endovascular aortic repair (TEVAR) is currently indicated. This review aims to present pathophysiology, CT diagnosis, and IMH fate and provide the reader CT image-based review of the CT diagnostic criteria, complications, and associated critical prognostic findings of this rather rare aortic disease.

Computed Tomography Angiography for Aortic Diseases

Aortic pathologies encompass a heterogeneous group of disorders, including acute aortic syndrome, traumatic aortic injury , aneurysm, aortitis, and atherosclerosis. The clinical manifestations of these disorders can be varied and non-specific, ranging from acute presentations in the emergency department to chronic incidental findings in an outpatient setting. Given the non-specific nature of their clinical presentations, the reliance on non-invasive imaging for screening, definitive diagnosis, therapeutic strategy planning, and post-intervention surveillance has become paramount. Commonly used imaging modalities include ultrasound, computed tomography (CT), and MR imaging. Among these modalities, computed tomography angiography (CTA) has emerged as a first-line imaging modality owing to its excellent anatomic detail, widespread availability, established imaging protocols, evidence-proven indications, and rapid acquisition time.

A single-center experience of type B aortic intramural hematoma

OBJECTIVE

The outcomes of the best medical treatment (BMT) and intervention treatment (INT) in a single-center experience were reported in type B intramural hematoma (IMH).

METHODS

From February 2015 to February 2021, a total of 195 consecutive patients with type B IMH were enrolled in the study. The primary end point was mortality, and the secondary end points included clinical and imaging outcomes. The clinical outcomes were aortic-related death, retrograde type A aortic dissection, stent graft-induced new entry tear, endoleak, and reintervention. The imaging outcome was evaluated through the latest follow-up computed tomography angiography, which included aortic rupture, aortic dissection, aortic aneurysm, rapid growth of aortic diameter, newly developed or enlarged penetrating aortic ulcer or ulcer-like projection (ULP) and increased aortic wall thickness. Kaplan-Meier curves were used to assess the association between different treatments.

RESULTS

Among the enrolled patients, 115 received BMT, and 80 received INT. There was no significant difference in early (1.7% vs 2.5%; P = 1.00) and midterm all-cause death (8.3% vs 5.2%; P = .42) between the BMT and INT groups. However, patients who underwent INT were at risk of procedure-related complications such as stent graft-induced new entry tear and endoleaks. The INT group was associated with a profound decrease in the risk of ULP, including newly developed ULP (4.3% vs 26.9%; P < .05), ULP enlargement (6.4% vs 31.3%; P < .05), and a lower proportion of high-risk ULP (10.9% vs 45.6%; P < .05). Although there was no significant difference in the incidence of IMH regression between the two groups, the maximum diameter of the descending aorta in patients receiving INT was larger compared with those treated with BMT.

CONCLUSIONS

Based on our limited experience, patients with type B IMH treated with BMT or INT shared similar midterm clinical outcome. Patients who underwent INT may have a decreased risk of ULPs, but a higher risk of procedure-related events and patients on BMT should be closely monitored for ULP progression.

Initial thickness of the crescent may not be a reliable predictor of complications in type A intramural haematoma

OBJECTIVES

This study aimed to investigate changes in haematoma thickness during the early period and their association with disease progression in patients who received initial medical treatment for type A intramural haematoma (IMH).

METHODS

Medical records and serial computed tomography angiography (CTA) images of patients who did not undergo emergency aortic repair for type A IMH upon presentation were retrospectively reviewed. The haematoma remodelling rate was determined using the following equation: thickness of the haematoma on the first CTA (mm) - thickness of the haematoma on the second CTA (mm)time between the first and second CTAs (h).

RESULTS

Among the 40 patients included in this study, 38 were indicated for initial watch-and-wait strategy, whereas 2 were indicated for emergency aortic repair but declined it. During hospitalization, 10 patients developed disease progression, with 2 in-hospital mortality cases. Analysis of the haematoma remodelling rate in 39 patients revealed that such a rate was significantly associated with the reciprocal of the time from onset. Analysis of all 70 CTA examinations performed within 24 h after the onset of IMH showed that haematoma thickness was significantly associated with the logarithm of the time from onset. Initial regression of the haematoma was not necessarily associated with avoidance of disease progression.

CONCLUSIONS

In type A IMH, the thickness of the haematoma in the ascending aorta tended to decrease in the very early period; however, prompt regression of the haematoma was not necessarily associated with avoidance of disease progression.

Comparison of population characteristics and clinical outcomes of patients with type B aortic dissection or aortic intramural hematoma underwent thoracic endovascular aortic repair: a propensity score-matched analysis

BACKGROUNDS

Survival and aortic-related adverse events after thoracic endovascular aortic repair (TEVAR) for aortic intramural hematoma (IMH) and aortic dissection (AD) are controversial. We aimed to assess the preoperative characteristics and to evaluate TEVAR outcomes of acute type B IMH and AD.

METHODS

Between June 2002 and May 2021, 83 patients with acute type B IMH and 755 patients with acute type B AD underwent TEVAR at the General Hospital of Northern Theater Command. We retrospectively analyzed data from these patients, including clinical characteristics and follow-up outcomes.

RESULTS

The patients with IMH were significantly older than the ones with AD (P < 0.001). Diabetes mellitus (P = 0.035) and ischemic cerebrovascular disease (P = 0.017) were more common in the IMH group than in the AD group. The results demonstrated a less long-term aortic-related death-free survival rate in the IMH group than the AD group for all the patients (P = 0.014) and the matched patients (P = 0.027). It also presents a lower long-term overall survival rate (P = 0.047) and aortic-related event-free rate (P = 0.048) in the IMH group than in the matched patients.

CONCLUSIONS

Compared with AD patients, patients with IMH who underwent TEVAR had a worse long-term outcome of aortic-related survival in all and matched patients.

Bib Sign in Proximal Descending Thoracic Aorta Rupture on CT Angiography: Presentation of a Paradigmatic Case

Thoracic aortic rupture may present with subtle clinical and CT-angiography findings. Recognition of the imaging features of early rupture is key for timely diagnosis and treatment. This report presents a new sign of incipient proximal thoracic aortic rupture on CT-angiography.

Clinical and Imaging Predictors of Disease Progression in Type B Aortic Intramural Hematomas and Penetrating Aortic Ulcers: A Systematic Review

BACKGROUND

This work aims to review recent literature on penetrating aortic ulcers (PAUs) and intramural hematomas (IMHs), in order to identify clinical and imaging factors connected to aortic-related adverse events (AAE).

METHODS

We performed a systematic review according to the Preferred Reporting Items for Systematic review and Metanalyses (PRISMA) guidelines. An electronic search was conducted on Medline and Embase databases. We included articles reporting on PAUs and/or IMHs localized in the descending thoracic and/or abdominal aorta and analyzing clinical and/or radiological markers of AAE.

RESULTS

Of 964 records identified through database searching, 17 were incorporated in the present review, including 193 and 1298 patients with type B PAUs and IMHs, respectively. The 30-days aortic-related mortality (ARM) was 4.3% and 3.9% for PAUs and IMHs. A total of 21% of patients with IMHs underwent intervention during the follow-up period, and 32% experienced an AAE. PAU markers of AAE were minimum depth (ranging from 9.5 to 15 mm) and diameter (≥12.5 mm). Maximum aortic diameter (MAD) cut-off values ranging from 38 to 44.75 mm were related to AAE for IMHs, together with ulcer-like projection (ULP) of the aortic wall.

CONCLUSIONS

Despite data heterogeneity in the literature, this PAU- and IMH-focused review has highlighted the imaging and clinical markers of disease progression, thus identifying patients that could benefit from an early intervention in order to reduce the AAE rate.

Endovascular treatment of traumatic renal artery pseudoaneurysm with a Stanford type A intramural haematoma: A case report

BACKGROUND

Aortic intramural hematoma (IMH) associated with aortic branch tear and intramurally located pseudoaneurysm after blunt trauma has not been reported. Here, we report a case of progressive type A aortic IMH associated with a pseudoaneurysm arising from the injured proximal renal artery after blunt trauma.

CASE SUMMARY

During logging operations, a 66-year-old man experienced blunt force trauma after being injured by a fallen tree. He arrived at our trauma center with a left flank pain complaint. Computed tomography (CT) revealed a pseudoaneurysm arising from the proximal renal artery (localized within the aortic media) and Stanford type A IMH. A covered stent was deployed along the left main renal artery, bridging the pseudoaneurysm and covering the parent artery, successfully excluding the pseudoaneurysm as confirmed using aortography. However, although the degree of the pseudoaneurysm decreased, follow-up CT revealed remnant pseudoaneurysm, likely caused by an endoleak. Subsequently, a covered stent was additionally installed through the previously deployed covered stent. Successful exclusion of the pseudoaneurysm was confirmed using final aortography. In the 7-mo follow-up CT scan, the IMH and pseudoaneurysm completely disappeared with no evidence of stent-related complications.

CONCLUSION

Endovascular treatment such as stent-graft placement can be an effective and safe treatment for traumatic renal artery injury.

Predictors of Intervention in Acute Type B Aortic Penetrating Ulcer and Intramural Hematoma

We aimed to investigate predictors of intervention of acute type B aortic penetrating ulcer (PAU) and intramural hematoma (IMH). We conducted a retrospective chart review of all patients admitted for acute type B PAU or IMH in a tertiary referral hospital. Indications to intervention were "complicated" (rupture, impending rupture, malperfusion) or "high risk for unfavorable outcome" (refractory hypertension and/or pain despite best medical treatment, morphologic aortic evolution, transition to a new aortic syndrome, or increase in IMH/PAU depth >5 mm) during the acute/subacute phase. The primary outcomes were overall mortality, aortic-related mortality, and freedom from intervention. Time-dependent outcomes were estimated with Kaplan-Meier curves. Cox proportional hazards models were used to identify predictors of intervention and mortality. There were 54 acute aortic syndromes, 37 PAUs and 17 IMHs. Mean age was 69 ± 14 years and 33 patients (62.2%) were male. Six (11.5%) patients had complicated aortic syndromes and underwent urgent repair. Two (3.7%) additional patients developed an impending rupture during the acute phase. Eleven (21.1%) patients were classified as at "high risk" during the initial hospitalization. Overall, 22 (40.7%) patients required an aortic intervention during the initial admission (n = 16, 72.7% during the acute phase; n = 6, 27.3% during the subacute phase). In-hospital mortality was 5.5% (1 PAU and 2 IMH), and was aorta-related in all cases. For IMH, disease extension in >3 aortic zones (HR 1.94, 95%CI 1.17-32.6; p = 0.038) and presence of ulcer-like projections (ULPs) (HR 1.23, 95%CI 1.02-9.41; p = 0.042) were associated with the need for intervention. There were no aortic-related deaths or intervention during the chronic phase. PAU width >20 mm (HR 1.68, 95%CI 1.07-16.08; p = 0.014), PAU depth >15 mm (HR 6.74, 95%CI 1.31-34.18; p = 021), PAU depth/total aortic diameter >0.3 (HR 4.31, 95%CI 1.17-20.32; p = 0.043), and location at the level of the paravisceral aorta (HR 2.24, 95%CI 1.23-4.70; p = 0.035) were significantly associated with need for intervention. Six additional (16.2%) PAUs required intervention during the chronic phase owing to PAU growth. Maximum aortic diameter >35 mm was significantly associated with intervention (HR 1.45, 95%CI 1.00-2.32; p = 0.037). Acute symptomatic type B IMHs and PAUs are characterized by a high risk of complications during the first month from presentation. Morphologic features associated with intervention were IMH with ULPs or extension in more than 3 aortic zones, as well as PAUs with depth>15 mm, width >20 mm, or depth/aortic diameter ratio>0.3. A strict follow-up protocol or consideration for early intervention within 30 days from presentation should be taken into account for these high-risk patients. During the chronic phase imaging follow-up is particularly important for PAUs in order to identify progression to saccular aneurysms.

Pitfalls and Pearls of Imaging Non-traumatic Thoracic Aortic Disease

Imaging of the thoracic aorta is a common request in both the acute and outpatient settings, playing a crucial role in diagnosis and treatment planning of aortic disease. The findings of aortic pathology may be obvious or occult on imaging. Recognizing subtle changes is essential and may lead to early detection and prevention of serious morbidity and mortality. Knowledge of the anatomy and understanding the pathophysiology of aortic disease, as well as selecting the appropriate imaging modality and protocol will enable prompt diagnosis and early intervention of aortic pathology. Currently, computed tomography angiography and magnetic resonance angiography of the aorta are the most commonly used imaging modalities to evaluate the aorta. This review focuses on a spectrum of aortic pathology manifestations on computed tomography and magnetic resonance, including atherosclerosis and acute aortic syndromes, highlighting diagnostic challenges and approaches to aid in image interpretation.

Management of penetrating aortic ulcer and intramural hematoma in the thoracic aorta

Acute aortic syndrome is a broad clinical entity that encompasses several pathologies. Aortic dissection is a well-studied disorder, but the other most prominent disorders within the scope of acute aortic syndrome, penetrating aortic ulcer and intramural hematoma, are more nebulous in terms of their pathophysiology and treatment strategies. While patient risk factors, presenting symptoms, and medical and surgical management strategies are similar to those of aortic dissection, there are indeed nuanced differences unique to penetrating aortic ulcer and intramural hematoma that surgeons and acute care providers must consider while managing patients with these diagnoses. The aim of this review is to summarize patient demographics, pathophysiology, workup, and treatment strategies that are unique to penetrating aortic ulcer and intramural hematoma.

Management of spontaneous isolated intramural hematoma of the superior mesenteric artery: a single-center experience

PURPOSE

To investigate the clinical course and optimal management for spontaneous isolated intramural hematoma of the superior mesenteric artery (SIHSMA).

METHODS

From January 2015 to October 2020, a total of 31 consecutive patients with SIHSMA were included in this study. The demographics, clinical features, treatment details, imaging information, and outcomes were reviewed.

RESULTS

There were 24 males and 7 females, with a mean age of 54.9 years (SD 6.9 years). Seven patients (7/31, 23%) were associated with ulcer-like projection (ULP), one patient (1/31, 3%) with intramural blood pool (IBP), and the remaining twenty-three patients (23/31, 74%) had no ULP or IBP. All patients were initially managed conservatively and underwent a median follow-up of 25.5 months (IQR 14.5, 39.9), which showed 3 patients (3/31, 10%) subsequently underwent stenting (2 within 7 days and 1 after 1.5 months), 1 patient (1/31, 3%) progressed to a localized dissection 7 months later but remained stable and asymptomatic until the time of writing, and the remaining patients (27/31, 87%) had no progression. In the present cohort, the overall survival was 100% (31/31). The free-from progression and stenting rate under conservative treatment was 87% (27/31). The invasive intervention rate was 10% (3/31). The natural complete regression rate of IMH in patients without ULP was higher than those with ULP (91% [21/23] vs. 29% [2/7], p = .003).

CONCLUSION

The majority of patients with SIHSMA can be managed conservatively. Patients with ULP seemed to have a lower IMH regression rate than those without ULP.

CT of the Difficult Acute Aortic Syndrome

Acute aortic syndrome (AAS) is classically attributed to three underlying pathologic conditions-aortic dissection (AD), intramural hematoma (IMH), and penetrating atherosclerotic ulcer (PAU). In the majority of cases, the basics of image interpretation are not difficult and have been extensively reviewed in the literature. In this article, the authors extend existing imaging overviews of AAS by highlighting additional factors related to the diagnosis, classification, and characterization of difficult AAS cases. It has been well documented that AAS is caused not only by an AD but by a spectrum of lesions that often have overlap in imaging features and are not clearly distinguishable. Specifically, phase of contrast enhancement, flow artifacts, and flapless AD equivalents can complicate diagnosis and are discussed. While the A/B dichotomy of the Stanford system is still used, the authors subsequently emphasize the Society for Vascular Surgery's new guidelines for the description of acute aortic pathologic conditions given the expanded use of endovascular techniques used in aortic repair. In the final section, atypical aortic rupture and pitfalls are described. As examples of pericardial and shared sheath rupture become more prevalent in the literature, it is important to recognize contrast material third-spacing and mediastinal blood as potential mimics. By understanding these factors related to difficult cases of AAS, the diagnostic radiologist will be able to accurately refine CT interpretation and thus provide information that is best suited to directing management. Online supplemental material is available for this article. ^©RSNA, 2021.

IMPACT OF THORACIC ENDOVASCULAR AORTIC REPAIR TIMING ON AORTIC REMODELING IN ACUTE TYPE B AORTIC INTRAMURAL HEMATOMA

INTRODUCTION

Thoracic endovascular aortic repair (TEVAR) is increasingly utilized in the management of acute type B aortic intramural hematoma (TBIMH). Optimal timing for intervention has not been described. The aim of this study was to evaluate TEVAR timing on post-operative aortic remodeling.

METHODS

A retrospective chart review was performed on patients who underwent TEVAR for TBIMH from January 2008 to September 2018. Imaging was reviewed pre- and postoperatively. Primary data points included true lumen diameter (TLD) and total aortic diameter (TAD) at the site of maximal pathology. Primary endpoint was aortic remodeling evidenced by a TAD/TLD ratio closest to 1.0. Secondary outcome was occurrence of aortic-related adverse events and mortality (AREM): aortic rupture, aortic-related death, progression to dissection or need for aortic re-intervention within 12 months. Patients undergoing emergent TEVAR (within 24 hours, 'eTEVAR') were compared to the remainder - delayed TEVAR ('dTEVAR').

RESULTS

We analyzed 71 patients that underwent TEVAR FOR TBIMH; 25 underwent emergent TEVAR and 46 patients underwent dTEVAR (median: 5.5 days, range: 2-120 days). There were no differences in demographics and comorbidities and patients did not differ in presenting IMH thickness (12.6±3.1 mm vs. 11.3±4.1 mm, p=0.186) nor presenting TAD/TLD ratio (1.535±0.471 vs. 1.525±0.397, p=0.928) for eTEVAR and dTEVAR groups, respectively. eTEVAR patients had larger average presenting maximal descending aortic (DTA) diameter (45.8±14.3 mm vs. 38.2±7.5 mm, p=0.018) and higher incidence of penetrating aortic ulcer (PAU) on presenting CT angiography (52.0% vs 21.7%, p=0.033). Thirty day mortality was 2/25 (8.0%) for eTEVAR and 2/45 (4.4%) for dTEVAR (p=0.602). Postoperative aortic remodeling was more complete in the dTEVAR group (1.23±0.12 vs. 1.33±0.15, p=0.004). Case-control matching (controlling for presenting DTA diameter and PAU) on 30 patients still showed better aortic remodeling in the dTEVAR group (1.125±0.100 vs 1.348±0.42, p<0.001). The incidence of AREM was higher in the eTEVAR - 6/25 (24.0%) - group compared to the dTEVAR group - 2/46 (4.3%). At 12 months, freedom from AREM was higher in the dTEVAR group (95.7% vs. 76.0%, p=0.011). Postoperative TAD/TLD ratio was the best predictor for late aortic-related adverse events (AUROC=0.825, p=0.003).

CONCLUSION

TEVAR for acute type B IMH within 24 hours of admission is associated with lower aortic remodeling and higher occurrence of late aortic related adverse events and mortality. Delaying TEVAR when clinically possible could improve aortic remodeling and aortic-related outcomes.

The Epiaortic Ultrasound Diagnosis of Iatrogenic Subadventitial Hematoma

Iatrogenic aortic injury is a rare but potentially lethal complication of cardiac surgery. While sometimes resulting in aortic dissection or intramural hematoma, injury more frequently results in subadventitial hematoma, a more benign pathology. Here, we describe a case where intraoperative transesophageal echocardiography (TEE) identified such a hematoma but was unable to rule out dissection. Epiaortic ultrasound was subsequently performed, which definitively demonstrated the absence of a dissection flap or extraluminal flow. Per our review, this is the first report documenting the successful use of epiaortic imaging to identify subadventitial hematoma in the setting of inconclusive TEE findings.

[Acute localized dissection of the descending thoracic aorta: A diagnostic trap]

Localized dissection of the descending thoracic aorta; class 3 of the classification proposed by the European Society of Cardiology; is a short and limited length dissection involving the descending thoracic aorta. It is a rare and unrecognized variant that poses a clinical and radiological diagnostic challenge. Indeed, it is manifested by an aspecific clinical profile represented by the acute aortic syndrome and characterized by a confused radiological aspect that entangled with the other differential diagnoses. We would like to emphasize the rarity of this uncommon pathology and the difficulty encountered in defining it based on a case treated in our department and a review of the literature.

IgG4 aortitis of the ascending thoracic aorta: A case report and literature review

IgG4 aortitis is a recently recognized entity that can have clinical and imaging features that mimic acute aortic syndrome. Therefore, it is imperative for radiologists to be aware of how to potentially differentiate the two. Although this entity has been previously described via case reports and meta-analysis in the context of inflammatory abdominal aortic aneurysm, very few cases of ascending aortic involvement have been reported. In this case report, we present a case of a 60-year-old female transferred from another facility for an initial diagnosis of intramural hematoma of the ascending aorta and later found to have IgG4 aortitis post aortic root repair. This is a histologically confirmed case of multi-segmented IgG4 aortitis with rare involvement of both ascending and infra-renal aorta. We will briefly discuss the pathophysiology of IgG4 aortitis, along with review of literature.

Computed Tomography Angiography Assessment of Acute Aortic Syndromes: Classification, Differentiating Imaging Features, and Imaging Interpretation Pitfalls

An acute aortic syndrome (AAS) is an important life-threatening condition that requires early detection and management. Acute intramural hematoma (IMH), aortic dissection (AD) and penetrating atherosclerotic ulcer (PAU) are included in AAS. ADs can be classified using the well-known Stanford or DeBakey classification systems. However, these classification systems omit description of arch dissections, anatomic variants, and morphologic features that impact outcome. The Society for Vascular Surgery and Society of Thoracic Surgeons (SVS-STS) have recently introduced a classification system that classifies ADs according to the location of the entry tear (primary intimomedial tear, PIT) and the proximal and distal extent of involvement, but does not include description of all morphologic features that may have diagnostic and prognostic significance. This review describes these classification systems for ADs and other AAS entities as well as their limitations. Typical computed tomography angiography (CTA) imaging appearance and differentiating features of ADs, limited intimal tears (LITs), IMHs, intramural blood pools (IBPs), ulcer-like projections (ULPs), and PAUs will be discussed. Furthermore, this review highlights common imaging interpretation pitfalls, what should be included in a comprehensive CTA report, and provides a brief overview of current management options.

Demystifying penetrating atherosclerotic ulcer of aorta: unrealised tyrant of senile aortic changes

This review article describes demographic features, comorbidities, clinical and imaging findings, prognosis, and treatment strategies in penetrating atherosclerotic ulcer (PAU) and closely related entities using google scholar web search. PAU is one of the manifestations of the acute aortic syndrome (AAS) spectrum. The underlying aorta invariably shows atherosclerotic changes or aneurysmal dilatation. Hypertension is the most common contributing factor, with chest or back pain being the usual manifestation. Intramural hematoma (IMH) is the second entity associated with both PAU and aortic dissection (AD), more so with the latter. Chest radiograph can show mediastinal widening, pleural, or pericardial fluid in rupture. Computed tomography angiography (CTA) is the imaging modality of choice to visualize PAU, with magnetic resonance imaging (MRI) and transoesophageal echocardiography (TEE) adding diagnostic value. Lesser-known entities of intramural blood pool (IBP), limited intimal tears (LITs), and focal intimal disruptions (FID) are also encountered. PAU can form fistulous communication with adjacent organs whereas IMH may propagate to dissection. CTA aids in defining the management, open or endovascular options in surgical candidates.

Clinical medical decision-making of acute aortic intramural hematoma: A non-randomized retrospective case study

Objective

This study explored the timing of interventional treatment for acute intramural aortic hematoma (IMH) and the corresponding high-risk factors for its development into local aortic dissection (AD).

Method

This retrospective case study method examined clinical follow-up data of 42 patients with acute IMH between April 2013 and October 2016 from the First Affiliated Hospital of Xiʹan Jiaotong University. SPSS 17.0 and PPMS1.5 were used to analyze follow-up data spanning 3–12 months (mean, 7.5 ​± ​3.7 months).

Results

Patients were divided into the conversion group and the hematoma group according to whether they developed AD. Among them, 16 patients (38.1%) developed AD and were treated with thoracic endovascular aortic repair (TEVAR). The remaining patients (61.89%) were treated conservatively. After 1 week, the mean aortic diameter of the conversion versus hematoma group was significantly widened. Hemodynamically unstable patients and those with hematoma to the abdominal aorta extension were more likely to develop AD. Patient outcomes after TEVAR were similar between groups.

Conclusion

Our findings suggest that aortic isthmus diameter ≥3.0 ​cm, hematoma extending to the abdominal aorta, and hemodynamic instability are associated with AD development in acute IMH patents. TEVAR should be considered if hematoma thickening, calcification ingression, ulcer progression, or contrast enhancement within the intramural hematoma is noted beyond 2 weeks after IMH onset.

The usefulness of contrast-enhanced echocardiography in the diagnosis and management of intramural hematoma and aortic dissection: A case report

Contrast-enhanced transthoracic echocardiography (cTTE) plays an important role in the diagnosis of intramural hematoma (IMH) and aortic dissection (AD), and is also necessary for the adequate management from the assessment of findings. We hereby present an interesting case in which cTTE provides additional value over contrast-enhanced computed tomography (CT) in the diagnosis and the morphological characterization of IMH and AD. A 58-year-old man presented to the emergency department with intermittent chest pain. After emergency consultation, an enhanced CT scan showed an acute aortic intramural hematoma involving aortic arch and descending aorta. Nevertheless, the entry tear and false lumen flow direction were identified by cTTE, which suggested an acute type B AD.

Diagnosing Aortic Intramural Hematoma: Current Perspectives

Aortic intramural hematoma (AIH) is an entity within the acute aortic syndrome. Combination of a priori probability, clinical history, laboratory blood test and imaging techniques are the basis for diagnosis of AIH. This review is focused on all aspects related to diagnosis of patients with AIH, from clinical to imaging and analytical.

Imaging of the aortic root on high-pitch non-gated and ECG-gated CT: awareness is the key!

The aortic pathologies are well recognized on imaging. However, conventionally cardiac and proximal aortic abnormalities were only seen on dedicated cardiac or aortic studies due to need for ECG gating. Advances in CT technology have allowed motionless imaging of the chest and abdomen, leading to an increased visualization of cardiac and aortic root diseases on non-ECG-gated imaging. The advances are mostly driven by high pitch due to faster gantry rotation and table speed. The high-pitch scans are being increasingly used for variety of clinical indications because the images are free of motion artifact (both breathing and pulsation) as well as decreased radiation dose. Recognition of aortic root pathologies may be challenging due to lack of familiarity of radiologists with disease spectrum and their imaging appearance. It is important to recognize some of these conditions as early diagnosis and intervention is key to improving prognosis. We present a comprehensive review of proximal aortic anatomy, pathologies commonly seen at the aortic root, and their imaging appearances to familiarize radiologists with the diseases of this location.

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.

Natural courses and long-term results of type A acute aortic intramural haematoma and retrograde thrombosed type A acute aortic dissection: a single-centre experience

OBJECTIVES

Few reports on the outcomes of patients treated for Stanford type A acute aortic intramural haematoma (TAAIMH) and retrograde thrombosed type A acute aortic dissection exist. This study aimed to evaluate their long-term results and predictors of adverse outcomes.

METHODS

We retrospectively analysed 40 patients with TAAIMH and retrograde thrombosed type A acute aortic dissection. All patients underwent urgent surgery on presentation of life-threatening complications. Before discharge, 18 patients underwent open aortic surgery, and 22 were treated with medical therapy alone. Clinical features of these patients and image appearances were reviewed, and the relationship with overall survival, aortic events, and aortic death was investigated.

RESULTS

The in-hospital mortality rate was 4.5% (1 patient) with medical therapy alone and 11.1% (2 patients) with surgical intervention. No patient with initial medical therapy required urgent surgery for life-threatening complications beyond 3 days of admission. The overall survival and aortic death-free survival rates at 1, 5 and 10 years were 85.0%, 72.5% and 59.8% and 90.0%, 81.6% and 77.1%, respectively. TAAIMH associated with penetrating aortic ulcer (PAU) was a risk factor of aortic events (P = 0.020) and significantly influenced aortic death-free survival (P = 0.003).

CONCLUSIONS

Urgent surgery for complicated TAAIMH and retrograde thrombosed type A acute aortic dissection patients and initial medical therapy for uncomplicated patients show favourable long-term survival rates. TAAIMH is frequently associated with PAU; PAU enlargement is common. Although PAU can remain stable for years, it is a strong predictor of poor prognosis. For optimal long-term results, surgical repair is recommended for TAAIMH associated with PAU.

Computed Tomography Imaging Findings of Acute Aortic Pathologies

Acute aortic syndromes (AAS) encompass a spectrum of life-threatening conditions characterized by acute aortic pain. AAS include acute aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, and aneurysm rupture. The prognosis of AAS is clearly related to prompt diagnosis and appropriate management. The different types of AAS cannot be reliably differentiated solely based on clinical presentation since the clinical features are indistinguishable. Multidetector-row computed tomography (MDCT) with electrocardiographic gating (ECG-gated MDCT) has been used in the acute emergency setting as a powerful clinical tool, which enables rapid and specific diagnosis of aortic pathologies. ECG-gated MDCT significantly reduces motion artifact and avoids potential pitfalls in the diagnosis of AAS. The aim of this review is to evaluate the role of MDCT imaging in the assessment of AAS and to discuss the differentiation of this spectrum of aortic diseases with reference to the key imaging findings.

Conservative Management of Uncomplicated Acute Type B Intramural Hematoma of the Aorta Not Always Is the Right Solution

The natural course of intramural hematoma (IMH) of the aorta remains unpredictable and despite an increasing amount of literature reports its treatment is still debatable. IMH typically is diagnosed by computed tomography that has permitted to identify specific images whose onset, in uncomplicated cases, appears to be associated to a dismal prognosis. We report on a case series of acute uncomplicated type B IMH in which early detection of such findings, given the expected poor prognosis associated to the aorta-related mortality, suggests the need to shift toward an aggressive endovascular aortic repair in this subset of patients.

"Dark-blood" dual-energy computed tomography angiography for thoracic aortic wall imaging

OBJECTIVES

To assess the capability of a newly developed material decomposition method from contrast-enhanced dual-energy CT images, aiming to better visualize the aortic wall and aortic intramural hematoma (IMH), compared with true non-contrast (TNC) CT.

MATERIALS AND METHODS

Twenty-two patients (11 women; mean age, 61 ± 20 years) with acute chest pain underwent 25 dual-layer non-contrast and contrast-enhanced CT. CT-angiography images were retrospectively processed using two-material decomposition analysis, where we defined the first material as the content of a region of interest placed in the ascending aorta for each patient, and the second material as water. Two independent radiologists assessed the images from the second material termed "dark-blood" images and the TNC images regarding contrast-to-noise ratio (CNR) between the wall and the lumen, diagnostic quality regarding the presence of aortic wall thickening, and the inner/outer vessel wall conspicuity.

RESULTS

Diagnostic quality scores in normal aortic segments were 0.9 ± 0.3 and 2.7 ± 0.6 (p < 0.001) and wall conspicuity scores were 0.7 ± 0.5 and 1.8 ± 0.3 (p < 0.001) on TNC and dark-blood images, respectively. In aortic segments with IMH, diagnostic quality scores were 1.7 ± 0.5 and 2.4 ± 0.6 (p < 0.001) and wall conspicuity scores were 0.7 ± 0.7 and 1.8 ± 0.3 (p < 0.001) on TNC and dark-blood images, respectively. In normal aortic segments, CNRs were 0.3 ± 0.2 and 2.8 ± 0.9 on TNC and dark-blood images, respectively (p < 0.001). In aortic segments with IMH, CNRs were 0.3 ± 0.2 and 4.0 ± 1.0 on TNC and dark-blood images, respectively (p < 0.001).

CONCLUSIONS

Compared with true non-contrast CT, dark-blood material decomposition maps enhance quantitative and qualitative image quality for the assessment of normal aortic wall and IMH.

KEY POINTS

• Current dual-energy CT-angiography provides virtual non-contrast and bright-blood images. • Dark-blood images represent a new way to assess the vascular wall structure with dual-energy CT and can improve the lumen-to-wall contrast compared with true non-contrast CT. • This dual-energy CT material decomposition method is likely to improve contrast resolution in other applications as well, taking advantage of the high spatial resolution of CT.

Intramural hematoma and penetrating ulcer in the descending aorta: differences and similarities

Acute aortic syndromes include a variety of overlapping clinical and anatomic diseases. Intramural hematoma (IMH), penetrating atherosclerotic ulcer (PAU), and aortic dissection can occur as isolated processes or can be found in association. All these entities are potentially life threatening, so prompt diagnosis and treatment is of paramount importance. IMH and PAU affect patients with atherosclerotic risk factors and are located in the descending aorta in 60-70% of cases. IMH diagnosis can be correctly made in most cases. Aortic ulcer is a morphologic entity which comprises several entities-the differential diagnosis includes PAU, focal intimal disruptions (FID) in the context of IMH evolution and ulcerated atherosclerotic plaque. The pathophysiologic mechanism, evolution and prognosis differ somewhat between these entities. However, most PAU are diagnosed incidentally outside the acute phase. Persistent pain despite medical treatment, hemodynamic instability, maximum aortic diameter (MAD) >55 mm, significant periaortic hemorrhage and FID in acute phase of IMH are predictors of acute-phase mortality. In these cases, TEVAR or open surgery should be considered. In non-complicated IMH or PAU, without significant aortic enlargement, strict control of cardiovascular risk factors and frequent follow-up imaging appears to be a safe management strategy.

CT imaging of complications of aortic intramural hematoma: a pictorial essay

Aortic intramural hematoma (IMH) is a pathologic process with a clinical presentation identical to aortic dissection and associated with significant morbidity and mortality. Radiologists must be familiar with the imaging appearances of IMH as computed tomography (CT) plays a critical role in both diagnosis and patient management. The course of IMH is variable and the process may regress, remain stable, or progress in extent and therefore imaging findings associated with a negative prognosis must be recognized and included in the formal radiology report. Potentially life-threatening complications and findings associated with IMH include hemopericardium and cardiac tamponade, coexisting aortic dissection, ulcer-like projection, intramural blood pool, and extension of hematoma along the pulmonary or coronary arteries, which are identifiable with aortic protocol CT. The purpose of this pictorial review is to provide the reader with an image-based review of the diagnostic criteria, related complications, and associated critical prognostic features in patients presenting with aortic IMH.

Radiologic and Intraoperative Finding of Intimal Tear in Type A Intramural Hematoma of the Aorta

Aortic intramural hematoma (IMH) is described as "dissection without intimal tear" due to rhexis of vasa vasorum, which results in bleeding within the tunica media in the absence of intimal disruption or blood flow communication. The aim of our study is to validate perioperative evidence of intimal entry tear in IMH patients and to suggest that this entity may represent a part of a disease and not a separate disease.

Postcardiovascular Surgery Findings of the Thoracic Aorta

Various disease processes may affect the ascending thoracic aorta, aortic arch, and/or descending thoracic aorta, including aneurysms, dissections, intramural hematomas, penetrating atherosclerotic ulcers, and aortic transection/rupture. Many of those conditions require surgical intervention for repair. Multiple open and endovascular techniques are used for treatment of thoracic aortic pathology. It is imperative that the cardiothoracic radiologist have a thorough knowledge of the surgical techniques available, the expected postoperative imaging findings, and the complications that may occur to accurately diagnose life-threatening pathology when present, and avoid common pitfalls of misinterpreting normal postoperative findings as pathologic conditions.

Proposed Magnetic Resonance Imaging Criteria to Diagnose Intramural Haematoma and to Predict Aortic Healing after Acute Type B Aortic Syndrome

OBJECTIVE

Type B acute aortic syndrome (AAS) encompasses aortic dissection (AD) and intramural haematoma (IMH), the diagnosis, evolution, and treatment of which are subject to controversies. The aim of this pilot investigation was to assess the ability of specific magnetic resonance imaging (MRI) criteria to differentiate AD from IMH and predict optimal aortic remodeling following AAS.

METHODS

In this retrospective study, all patients presenting between 2008 and 2015 with type B AAS, who had diagnostic MRI following admission, were included. Three MRI criteria were proposed to identify IMH: (i) no visualised entry tear; (ii) no contrast uptake in the aortic lesion on the first pass angiographic run; (iii) no contrast uptake in the aortic lesion on the equilibrium phase T1 sequence. On each patient's diagnostic and follow up imaging studies, the volume of (i) false lumen/IMH, (ii) total aorta, and (iii) true lumen were calculated. Using the Wilcoxon signed rank test, the evolution of these volumes according to the presence or absence of the aforementioned criteria were compared.

RESULTS

Of 39 patients, in seven all MRI criteria were positive (group IMH) and 32 had one or more negative criteria (group AD). Patients with IMH and AD were similar with respect to sex, age, and delay between onset of symptoms and diagnostic and follow up imaging studies. Eighteen patients had a follow up imaging study after a mean period of 11.2 months: six in the IMH group and 12 in the AD group. Lesion volume decrease and relative true lumen volume increase were statistically significant in group IMH (p = .046 and p = .046, respectively), whereas there was a statistically significant increase of lesion volume (p = .008) in the AD group.

CONCLUSION

This pilot study proposed three simple MRI criteria to differentiate between AD and IMH. Once prospectively and clinically validated, this could have substantial therapeutic benefits as IMH are likely to heal spontaneously.

An aortic intra mural hematoma in ventilation/perfusion SPECT/CT: A case report

RATIONALE

Ventilation/perfusion (V/Q) single-photon-emission computed tomography (SPECT) has arisen as an alternative to computed tomography pulmonary angiography (CTPA) in patients with pulmonary embolism (PE) suspicion. The addition of low dose CT (ldCT) to V/Q SPECT improves the specificity of the test, allowing for potential alternative diagnosis.

PATIENT CONCERNS AND DIAGNOSIS

Here we presented a case of an aortic intramural hematoma (IMH) diagnosed on the ldCT portion of V/Q SPECT combined with CT. A 74-year-old man suffering from sudden-onset chest pain was referred to our nuclear medicine department for PE suspicion.

INTERVENTION AND OUTCOME

A V/Q SPECT combined with nonenhanced ldCT ruled out PE diagnosis. Nevertheless, ldCT revealed high attenuation aortic wall thickening suggestive of aortic IMH. Chest CT angiography showed mild dilatation and circumferential thickening of aortic wall confirming Stanford type A IMH involving the entire ascending aorta.

LESSON

This case illustrates the potential usefulness of combining ldCT to V/Q SPECT in providing alternative diagnosis in suspected PE patients.

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.

Multi-Detector Computed Tomography Imaging Techniques in Arterial Injuries

Cross-sectional imaging has become a critical aspect in the evaluation of arterial injuries. In particular, angiography using computed tomography (CT) is the imaging of choice. A variety of techniques and options are available when evaluating for arterial injuries. Techniques involve contrast bolus, various phases of contrast enhancement, multiplanar reconstruction, volume rendering, and maximum intensity projection. After the images are rendered, a variety of features may be seen that diagnose the injury. This article provides a general overview of the techniques, important findings, and pitfalls in cross sectional imaging of arterial imaging, particularly in relation to computed tomography. In addition, the future directions of computed tomography, including a few techniques in the process of development, is also discussed.

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.