Fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography for diagnosis of infected aortic aneurysms

Coexistence of FDG-Avid and FDG-Negative Aneurysms in a Patient With Fever of Unknown Origin

ABSTRACT

A 68-year-old man with intermittent fever of unknown origin for 5 months underwent 18F-FDG PET/CT to detect causative lesion. An 18F-FDG-avid lesion was revealed in the left pelvic iliac vessel region and was highly suggestive of malignancy. One and a half months later, a giant left internal iliac artery aneurysm was identified by CT angiography, corresponding to the 18F-FDG-avid lesion. Combined with elevated inflammatory markers, he was finally diagnosed as having inflammatory internal iliac artery aneurysm. An abdominal aortic aneurysm with low 18F-FDG uptake was also identified.

ACR Appropriateness Criteria® Pulsatile Abdominal Mass, Suspected Abdominal Aortic Aneurysm: 2023 Update

Abdominal aortic aneurysm (AAA) is defined as abnormal dilation of the infrarenal abdominal aortic diameter to 3.0 cm or greater. The natural history of AAA consists of progressive expansion and potential rupture. Although most AAAs are clinically silent, a pulsatile abdominal mass identified on physical examination may indicate the presence of an AAA. When an AAA is suspected, an imaging study is essential to confirm the diagnosis. This document reviews the relative appropriateness of various imaging procedures for the initial evaluation of suspected AAA. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Brazilian Society for Angiology and Vascular Surgery guidelines on abdominal aortic aneurysm

The Brazilian Society of Angiology and Vascular Surgery, through the Guidelines Project, presents new Abdominal Aortic Aneurysm Guidelines, on the subject of care for abdominal aortic aneurysm patients. Its development prioritized descriptive guidelines, using the EMBASE, LILACS, and PubMed databases. References include randomized controlled trials, systematic reviews, meta-analyses, and cohort studies. Quality of evidence was evaluated by a pair of coordinators, aided by the RoB 2 Cochrane tool and the Newcastle Ottawa Scale forms. The subjects include juxtarenal aneurysms, infected aneurysms, and new therapeutic techniques, especially endovascular procedures. The current version of the guidelines include important recommendations for the primary topics involving diagnosis, treatment, and follow-up for abdominal aortic aneurysm patients, providing an objective guide for medical practice, based on scientific evidence and widely available throughout Brazil.

Patient-tailored approach for diagnostics and treatment of mycotic abdominal aortic aneurysm

OBJECTIVE

The existing literature on mycotic aortic aneurysm is scarce and focuses on treatment. This study evaluates the clinical characteristics, diagnostics, treatment and outcome of patients with a mycotic abdominal aortic aneurysm treated in a tertiary referral center.

METHODS

A retrospective cohort study was conducted including all patients with a proven mycotic abdominal aortic aneurysm admitted between May 2010 and July 2020. Primary outcome was mortality and secondary outcome included complications such as vascular graft/endograft infection.

RESULTS

Twenty-four patients with a mycotic abdominal aortic aneurysm were included. Patients had a mean age of 68 ± 9 years and 20 (83%) were male. Thirteen patients (57%) had positive preoperative blood cultures. Streptococcus pneumoniae was most frequently isolated by blood culturing, pus, and vascular or perivascular tissue cultures (17%). In 19 (83%) patients the mycotic abdominal aortic aneurysm was located infrarenally, in three (13%) patients suprarenally, and in one (4%) patient juxtarenally. Median follow-up was 20 (7-42) months. In eight patients (33%) vascular graft and or endograft infection was diagnosed after surgical repair. Ten (42%) patients died during the follow-up period. The main causes of death were vascular graft/endograft infection-related (n=4) and rupture of the mycotic abdominal aortic aneurysm (n=3). No patient characteristics could be identified as predictive for mortality.

CONCLUSION

This study shows a large variation in presentation, diagnostic approaches, and surgical and antibiotic treatment of mycotic abdominal aortic aneurysm. The detailed information about the diagnostic approaches to this rare disease and its antibiotic/other treatment contributes to existing knowledge of mycotic abdominal aortic aneurysm. Because of the individual variation patients should be discussed in a multidisciplinary team with a vascular surgeon, infectious disease specialist, and clinical microbiologist.

PET-Based Imaging with 18F-FDG and 18F-NaF to Assess Inflammation and Microcalcification in Atherosclerosis and Other Vascular and Thrombotic Disorders

Positron emission tomography (PET) imaging with ¹⁸F-fluorodeoxyglucose (FDG) represents a method of detecting and characterizing arterial wall inflammation, with potential applications in the early assessment of vascular disorders such as atherosclerosis. By portraying early-stage molecular changes, FDG-PET findings have previously been shown to correlate with atherosclerosis progression. In addition, recent studies have suggested that microcalcification revealed by ¹⁸F-sodium fluoride (NaF) may be more sensitive at detecting atherogenic changes compared to FDG-PET. In this review, we summarize the roles of FDG and NaF in the assessment of atherosclerosis and discuss the role of global assessment in quantification of the vascular disease burden. Furthermore, we will review the emerging applications of FDG-PET in various vascular disorders, including pulmonary embolism, as well as inflammatory and infectious vascular diseases.

18F-fluorodeoxyglucose positron emission tomography/ computed tomography in the diagnosis of a rare mycotic aneurysm of the thoracic aorta in a patient with fever of unknown origin

Fever of unknown origin (FUO) is a condition with high mortality that often presents a diagnostic challenge to clinicians. We present the case of a patient with FUO who was discovered to have a rare mycotic aneurysm of the thoracic aorta by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Mycotic aneurysm, also known as an infected aneurysm, is a highly lethal condition due to the risk of sepsis and aneurysmal rupture. While unusual to present in this manner, it is of utmost importance to promptly recognize a mycotic aneurysm as a potential diagnosis because initiation of treatment is critical in reversing the natural history of the disease.

Prospect of positron emission tomography for abdominal aortic aneurysm risk stratification

Abdominal aortic aneurysm (AAA) disease is characterized by an asymptomatic, permanent, focal dilatation of the abdominal aorta progressing towards rupture, which confers significant mortality. Patient management and surgical decisions rely on aortic diameter measurements via abdominal ultrasound surveillance. However, AAA rupture can occur at small diameters or may never occur at large diameters, implying that anatomical size is not necessarily a sufficient indicator. Molecular imaging may help identify high-risk patients through AAA evaluation independent of aneurysm size, and there is the question of the potential role of positron emission tomography (PET) and emerging role of novel radiotracers for AAA. Therefore, this review summarizes PET studies conducted in the last 10 years and discusses the usefulness of PET radiotracers for AAA risk stratification. The most frequently reported radiotracer was [18F]fluorodeoxyglucose, indicating inflammatory activity and reflecting the biomechanical properties of AAA. Emerging radiotracers include [18F]-labeled sodium fluoride, a calcification marker, [64Cu]DOTA-ECL1i, an indicator of chemokine receptor type 2 expression, and [18F]fluorothymidine, a marker of cell proliferation. For novel radiotracers, preliminary trials in patients are warranted before their widespread clinical implementation. AAA rupture risk is challenging to evaluate; therefore, clinicians may benefit from PET-based risk assessment to guide patient management and surgical decisions.

Culture-Negative Mycotic Aortic Aneurysms Probably Have a Less Severe Clinical Nature Than Culture-Positive Counterparts

BACKGROUND

Mycotic aortic aneurysm constitutes a potentially devastating disease that necessitates prompt suspicion and diagnosis. There is no exact consensus for treatment, but removal of infected tissues and prolonged use of antimicrobials based on the identified causative microorganisms seem widely acceptable and have been similarly practiced worldwide. However, some patients still show no identified microorganisms. In this study, we sought to determine whether there are any clinical significance or differences of note in culture-negative mycotic aortic aneurysms.

METHODS

Between October 2003 and August 2018, 71 patients were identified as treated for mycotic aortic aneurysms at a single tertiary institution. Review of medical records and imaging studies were completed to collect the following information: demographics, previous medical/surgical history regarding potential infection sources, laboratory and radiologic findings, clinical presentations, treatment method, and morbidity and mortality rates. For analysis, patients were categorized into two groups: the blood and/or tissue culture-positive (CP) group and the blood and/or tissue culture-negative (CN) group. The latter was further divided as CN with identified microorganism by molecular biologic methods [CN(+)] and CN with no identified microorganism [CN(-)].

RESULTS

More patients in the CP group were symptomatic than were in the CN(+) group (100% vs. 80%; P = 0.034). However, identification of causative microorganisms did not result in a difference in symptom status upon comparing the [CP + CN(+)] and [CN(-)] groups. Inflammatory markers were the most elevated in the CP group and least elevated in the CN(-) group. The aneurysm growth rate seemed slower in the CN(-) group than in the CN(+) and CP groups (1.3 vs. 3.4 vs. 9 mm/month respectively). Aneurysm rupture at initial presentation was more prevalent in the CP group (33.3%). ¹⁸F-Fluorodeoxyglucose-positron emission tomography showed increased uptake regardless of whether or not the microorganisms were identified. Early mortality and disease-specific mortality rates during the follow-up period were higher in the CP group but without statistical significance.

CONCLUSIONS

Compared with the CP group, the CN groups appeared clinically less severe, and also exhibited a relatively less devastating course as exhibited by the slower aneurysm expansion rate and smaller number of ruptured aneurysms at the initial presentation.

The value of 18F-FDG-PET-CT in the management of infective native aortic aneurysms

OBJECTIVE

The objective of this systematic literature review was to explore the value of positron emission tomography combined with low-dose computed tomography (18F-FDG-PET-CT) in the diagnostics of infective native aortic aneurysm (INAA).

METHODS

A systematic literature review was performed using the search terms mycotic- and infected aortic aneurysms in Medline and Sciencedirect databases, published between 1 January 2000 and 1 January 2020. Using the PRISMA statement, articles were scrutinized according to a predefined protocol including: timing of 18F-FDG-PET-CT examination, the maximum standardized uptake value (SUVmax), additional findings on examination, and findings on repeated scanning of 18F-FDG-PET-CT.

RESULTS

Four studies were included in the analysis, comprising a total of 11 patients. Two studies were single case reports, and two were small case series, all were graded to be of low quality with high risk of bias. All patients were examined with a preoperative 18F-FDG-PET-CT, and 10 (91%) had increased 18F-FDG uptakes. The median SUVmax value was 6.53, range 4.46-9.23. The mean duration of antibiotic therapy prior to 18F-FDG-PET-CT was not known. Two patients were examined with repeated 18F-FDG-PET-CT examinations after treatment, where a decrease in SUVmax values could be demonstrated after successful treatment.

CONCLUSION

The literature on 18F-FDF-PET/CT for diagnosing infective native aortic aneurysms is scarce. However, there might be a role for 18F-FDF-PET/CT in the management of the disease, in particular for patients with clinical suspicion of INAA without convincing findings on CT. SUVmax values ranging from 4.5 to 6.5 could be guiding and suggestive of metabolic activity in agreement of INAA. However, further conclusions on its usefulness, robustness and specific SUVmax values are premature, and a definitive cut-off value is probably not attainable.

Therapy Control in a Patient With an Inflammatory Abdominal Aneurysm: Potential Pitfalls in PET/CT Imaging

We present a case of inflammatory abdominal arterial aneurysms, which demonstrates the potential usefulness of PET/CT with F-FDG in long-term monitoring of this disease, but also demonstrates potential pitfalls in abdominal arterial aneurysm imaging with PET/CT. Imaging may be challenged as the initial presentation prior to therapy may mimic an infected aneurysm. Follow-up images may be mistaken for vascular graft infection or persistent disease.

Vascular findings on FDG PET/CT

Since its introduction into clinical practice, 2-deoxy-2-[18F]flu-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has become firmly established in the field of oncological imaging, with a growing body of evidence demonstrating its use in infectious and inflammatory vascular pathologies. This pictorial review illustrates the utility of FDG PET/CT as a diagnostic tool in the investigation of vascular disease and highlights some of the more common incidental vascular findings that PET reporters may encounter on standard oncology FDG PET/CTs, including atherosclerosis, large vessel vasculitis, complications of vascular grafts, infectious aortitis and acute aortic syndromes.

Diagnostic Accuracy of PET/CT and Contrast Enhanced CT in Patients With Suspected Infected Aortic Aneurysms

OBJECTIVE

Infected aortic aneurysms are highly lethal, and management is very demanding, requiring an early diagnosis. The aim of this study was to evaluate the diagnostic accuracy of positron emission tomography/computed tomography with ¹⁸F-fluorodeoxyglucose (PET/CT) and contrast enhanced CT (CE-CT) in patients with suspected infected aortic aneurysms.

METHODS

PET/CT was performed in patients with clinically suspected infected aortic aneurysms, and additional CE-CT was performed if feasible. Diagnostic accuracy was assessed by two independent readers using a four point grading score for both imaging modalities. Maximum standardised uptake values (SUV_max) were calculated for quantitative measurements of metabolic activity in PET/CT. The reference standard was a combination of clinical presentation, laboratory findings, and imaging.

RESULTS

Ten patients were included prospectively in the study, 24 retrospectively; 16 patients (47%) prior to the start of antimicrobial treatment and all 34 patients prior to any vascular intervention. Thirteen of the 34 patients had an infected aortic aneurysm (38%). Proven infected aortic aneurysms were all metabolically active on PET/CT with a median SUV_max of 6.6 (interquartile range 4.7-21.8). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT for the diagnosis of infected aortic aneurysm was 100%, 71%, 68%, 100%, and 82%, for reader 1 and 85%, 71%, 65%, 88%, and 77%, for reader 2. Respective values for CE-CT, performed in 20 patients (59%), were 63%, 75%, 63%, 75%, and 70%, for reader 1 and 88%, 50%, 54%, 86%, and 65%, for reader 2.

CONCLUSION

The diagnostic accuracy of PET/CT in the detection of infected aortic aneurysms (n = 13) is high, and higher than CE-CT. While PET/CT demonstrates an excellent sensitivity, its specificity is hampered because of false positive findings.

Aortic sarcoma mimicking a mycotic aneurysm in the thoracoabdominal aorta

Aortic sarcoma is a rare primary tumor with dismal prognosis. Here, we report a case involving a 74-year-old female patient with aortic sarcoma masquerading as a mycotic aneurysm in the thoracoabdominal aorta. She underwent aortic resection with Dacron prosthetic graft replacement because of rapid growth. The postoperative pathological findings of the resected specimen confirmed the diagnosis of aortic mural sarcoma, which was an unexpected result based on repeat computed tomography angiography performed within 2 months preoperatively. The preoperative diagnosis of aortic sarcoma is often difficult because of its rarity, and this case demonstrates some of the diagnostic pitfalls.

Aortoenteric fistula secondary to an Inflammatory Abdominal Aortic Aneurysm

Primary aortoenteric fistulas are rare, with the annual incidence of such fistulas estimated to be 0.007 per million. The most common predisposing conditions for primary aortoenteric fistulas are atherosclerotic abdominal aortic aneurysms or penetrating atherosclerotic ulcers. We illustrate a rare case of an inflammatory aortic aneurysm causing a primary aortic fistula, with a direct fistulous jet from the aorta to the bowel with resultant catastrophic bleeding. In contrast to atherosclerotic aneurysms, most inflammatory aneurysms are symptomatic and show dense perianeurysmal fibrosis and periaortic wall thickening. A direct jet of contrast extravasation from the aorta into a bowel loop, while rarely seen, remains the most specific sign of a primary aorta-enteric fistula. A comprehensive literature review of the clinical presentation, imaging features, and differential diagnosis of a primary aortoenteric fistula are also discussed.

Total resection of an infected aortic arch aneurysm caused by Mycobacterium avium: a case report

Background

Infected aortic arch aneurysms caused by Mycobacterium avium are rare in immunocompetent individuals. Promptly recognizing these aneurysms is important because delays in treatment result in aneurysm rupture and a high fatality rate. Although Salmonella species, Streptococcus species, Staphylococcus aureus, and S. epidermis are commonly found in immunocompetent individuals, to our knowledge, infected aortic arch aneurysms caused by M. avium have not yet been reported.

Case presentation

We report the case of a 63-year old immunocompetent man who underwent total arch replacement following infection by the nontuberculous mycobacteria M. avium. The procedure involved total aneurysmal resection and arch replacement with a rifampicin-bonded gelatin-sealed woven Dacron graft. He was discharged without complications and remained asymptomatic after 30 months.

Conclusion

In this brief report, we outline and discuss the rare successful case of total arch replacement using total aneurysmal resection and rifampicin-bonded gelatin-sealed woven Dacron graft for an infected aortic arch aneurysm resulting from M. avium in an immunocompetent patient.

Mycotic aortic aneurysms treated by endovascular repair: initial experience in a single center

INTRODUCTION

Mycotic aortic aneurysm (MAA) is an uncommon cause of aneurysmal aortic disease. However, it may have an aggressive presentation and a complicated early outcome. Endovascular aneurysm repair (EVAR) of MAA is emerging as an alternative to open repair (OR) for the treatment of these aneurysms, particularly in high-risk surgical patients. We report a single-center experience with the endovascular management of mycotic aortic aneurysms.

MATERIAL AND METHODS

Two mycotic abdominal aortic aneurysms were treated with an endovascular stent graft at Centre Hospitalier Régional du Val de Sambre, Belgium. The mean follow-up was 15 months. Technical success was achieved in all two patients. CT-scan follow up showed shrinkage of the aneurysm sac, with no evidence of infection along the stent graft and no signs of endoleakage in all patients. One patient died during the follow-up period from a cause unrelated to the aneurysm.

CONCLUSION

EVAR is an effective and safe option and might be a suitable alternative to OR in the absence of predictors of poor prognosis for the treatment of non-complicated forms of MAA.

Role of PET/CT in the Evaluation of Aortic Disease

Positron emission tomography (PET) /computed tomography (CT) has been established as a standard imaging modality in the evaluation of malignancy. Although PET/CT has played a major role in the management of oncology patients, its clinical use has also increased for various disorders other than malignancy. Growing evidence shows that PET/CT images have many advantages in aortic disease as well. This review article addresses the potential role of PET/CT in diseases involving the aorta, emphasizing its usefulness with regard to acute thoracic aortic syndromes, aortic aneurysm, atherosclerotic lesions, aortitis and aortic tumors.

Surgical Treatment of Symptomatic Aortic Aneurysm in a Patient with Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis: Case Report and Review of the Literature

Vasculitis is an heterogeneous group of syndromes, which shares inflammation of blood vessel wall as the main feature. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, arterioles, and small arteries), associated with ANCAs specific for myeloperoxidase or proteinase 3. Clinical manifestations may be heterogeneous but an involvement of lungs and kidneys frequently occurs. AAV of large vessels is a very rare condition whose standard therapy is medical approach. Surgical revascularization has been described in selected patients after medical failure or in emergent settings. We report the case of a patient affected by symptomatic infrarenal aortic aneurysm related to AAV, who underwent in-situ reconstruction by means of cryopreserved homograft.

Surgery for Acute Presentation of Thoracoabdominal Aortic Disease

Thoracoabdominal aortic aneurysms are most commonly asymptomatic until there is either an impending aortic catastrophe or one that has already occurred. While open surgery remains the gold-standard method for repair, modern technology has led to the development of less invasive endovascular devices and techniques. We provide an expert review of open and endovascular therapies for 3 highly lethal thoracoabdominal aortic emergencies in order to highlight expectations for both short- and long-term outcomes in an era of evolving technology and improvements in patient evaluation and postoperative care. Open repair of ruptured thoracoabdominal aortic aneurysms is associated with a dramatic increase in all postoperative complications, even in specialized aortic surgery centers. Mycotic thoracic aortic aneurysms are highly lethal if surgical treatment is not initiated quickly as they have a propensity toward rapid growth and fatal rupture. Thoracic endovascular aortic repair is well-suited for the treatment of acute complicated type B aortic dissection with outcomes superior to open repair in some centers. Acute aortic events associated with thoracoabdominal aneurysms represent technically challenging situations that require rapid diagnosis and treatment to avoid a fatal outcome. Endovascular techniques have evolved as a viable alternative therapy for acute complicated type B aortic dissection or as a bridge to more definitive repair in the setting of infection or rupture.

Inflammatory and infectious aortic diseases

Aortitis is aortic inflammation, which can be due to inflammatory or infectious diseases. Left undiagnosed, aortitis can lead to aneurysm formation and rupture, in addition to ischemic compromise of major organs. Infectious aortic diseases include mycotic aneurysm and graft infection; the most common inflammatory diseases are Takayasu's and giant cell arteritis. We review the epidemiology, etiology, presentation and diagnosis, and treatment of these entities.

Clinical experience of positron-emission tomography in infective aortic disease

Background

Fluorine-18-fluorodeoxyglucose positron-emission tomography with computed tomography has revolutionized medical diagnosis by adding functional activity to anatomic imaging. We report our experience with this technique in patients with mycotic aortic pathology and aortic vascular graft infection.

Methods

We conducted a retrospective review of a prospective database of patients who underwent 18F-fluorodeoxyglucose positron-emission tomography with computed tomography for suspected infective aortic disease. From 2012 to 2016, 13 patients underwent 18F-fluorodeoxyglucose positron-emission tomography. Of these, 9 (69%) had a vascular graft infection (5 infrarenal aorta, 1 para-visceral, 2 descending, and 1 arch; 2 had previous open surgery and 7 had endovascular interventions) and 4 (31%) had a mycotic aneurysm (2 aortic arch, 1 infrarenal aorta, and 1 distal aorta and common iliac; 3 had endografts). The indications for imaging, location of pathology, 18F uptake, and clinical outcomes were analyzed.

Results

Eight (62%) patients had a single scan and 5 (38%) had serial scans performed. Among the 5 patients who had serial imaging, 3 showed decreased 18F uptake and 2 had increased uptake. Only one patient underwent subsequent endograft removal; the others were treated with lifelong antibiotics. There were 5 (38%) deaths on follow-up.

Conclusion

18F-fluorodeoxyglucose positron-emission tomography with computed tomography could be a valuable adjunct in the diagnosis and surveillance of patients with aortic infection. Serial scans may be useful for monitoring disease activity and response to antibiotic therapy.

Metabolic Imaging as a Novel Strategy in Evaluation of Mycotic Abdominal Aortic Aneurysm: A Case Report and Brief Clinical Review

Abdominal aortic aneurysm (AAA) is an uncommon entity with high mortality. Etiologically, they are classified as inflammatory and infective (mycotic), the latter being less common. Clinical presentation, laboratory investigations, and treatment for these may considerably overlap. However, choice of management and the need for surgical intervention depends on factors such as size and progression of aneurysm, persistent symptoms, and presence or absence of distant pathology. Although computed tomography (CT) is the gold standard for AAA, in selected cases, especially in infected AAA, fluorodeoxyglucose positron emission tomography-CT can provide valuable information.

Multilevel Mycotic Aneurysms Due to Salmonella Infection: Case Report and Review of the Literature

Infected or mycotic aneurysms (MAs) of the aorta and adjacent arteries are rare and difficult to treat. We report a unique case of a Salmonella serotype enteritidis-induced rapidly expanding aortic and iliac pseudoaneurysm during preoperative workup. Based on the presented case, we postulate that the agressive nature of Salmonella enteritidis MAs should not be underestimated. If postponed intervention is chosen and the patient is managed conservatively with antibiotic therapy to create a window of definitive diagnosis, one should consider close follow-up imaging to observe progression of the pseudoaneurysm. This may prevent the need of acute intervention.

Cross-sectional imaging of aortic infections

Aortic infections are uncommon clinical entities, but are associated with high rates of morbidity and mortality. In this review, we focus on the cross-sectional imaging appearance of aortic infections, including aortic valve endocarditis, pyogenic aortitis, mycotic aneurysm and aortic graft infections, with an emphasis on CT, MRI and PET/CT appearance. Teaching Points • Aortic infections are associated with high morbidity and mortality. • CT, MRI and FDG PET/CT play complementary roles in aortic infection imaging. • Radiologists should be vigilant for aortic infection manifestations to ensure timely diagnosis.

Aspergillus thromboembolism from a mycotic ascending aortic pseudoaneurysm

This case report describes an immune-competent patient with acute upper extremity ischemia caused by thromboembolism from an Aspergillus-infected ascending aortic pseudoaneurysm. Efforts to identify the source of an acute arterial thromboembolic occlusion should be made, and a high index of suspicion for mycotic infection should be maintained in patients with an atypical presentation, such as fevers of unknown origin. Additional measures, such as pathologic examination of thromboembolic debris, blood cultures, and positron emission tomography, should be performed to identify the etiology in these unexplained situations.

Positron emission tomography-computed tomography for imaging of inflammatory cardiovascular diseases

Inflammation is a determinant of atherosclerotic plaque rupture, the event usually responsible for myocardial infarction and stroke. Possible causes of inflammatory cardiomyopathy include myocarditis, eosinophilic disease, and sarcoidosis. Although conventional imaging techniques can identify the site and severity of luminal stenosis, they do not provide information regarding inflammatory status. (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for imaging of inflammatory cardiovascular diseases has been rapidly evolving. Integrated PET/computed tomography (CT) is becoming the method of choice for quantification of arterial inflammation across multiple vessels. Moreover, PET/CT provides information about the activation status of inflammatory cells in the vessel wall, thus allowing early diagnosis and risk stratification of patients. The Japanese health insurance system approved reimbursement for FDG-PET use to detect inflammation sites in cardiac sarcoidosis as of April 2012. This approval has necessitated a more detailed assessment of the clinical value of FDG-PET. Standardized preparation, imaging, and image interpretation protocols should be established to sufficiently suppress physiological FDG uptake in the normal myocardium, and thereby facilitate detection of early-stage cardiac inflammatory lesions with more favorable specificity. This review summarizes the background, clinical utility, state-of-the-art advances, and potential future applications of FDG-PET for imaging inflammatory cardiovascular diseases including cardiac sarcoidosis, large-vessel arteritis, and atherosclerosis.