Early recognition of aortitis of the aorta ascendens with ¹⁸F-FDG PET/CT: syphilitic?

Ankylosing spondylitis PET imaging and quantifications via P2X7 receptor-targeting radioligand [18F]GSK1482160

PURPOSE

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the axial spine; however, the quantitative detection of inflammation in AS remains a challenge in clinical settings. We aimed to investigate the feasibility of using a specific P2X7R-targeting 18F-labeled tracer [18F]GSK1482160 for positron emission tomography (PET) imaging and the quantification of AS.

METHODS

The radioligand [18F]GSK1482160 was obtained based on nucleophilic aliphatic substitution. Dynamic [18F]GSK1482160 and [18F]FDG micro-PET/CT imaging were performed on AS mice (n = 8) and age-matched controls (n = 8). Tracer kinetics modeling was performed using Logan's graphical arterial input function analysis to quantify the in vivo expression of P2X7R. The post-PET tissues were collected for hematoxylin-eosin (H&E), immunohistochemical (IHC), and immunofluorescence (IF) staining.

RESULTS

[18F]GSK1482160 PET/CT imaging revealed that the specific binding in the ankle joint and sacroiliac joint (SIJ) of the AS at 8 weeks group (BPNDankle-AS-8W (non-displaceable binding potential of the ankle) 3.931 ± 0.74; BPND SIJ-AS-8W (BPBD of the SIJ) 4.225 ± 0.84) were significantly higher than the controls at 8 weeks group (BPNDankle-Ctr-8W 0.325 ± 0.15, BPNDSJJ-Ctr-8W 0.319 ± 0.17) respectively, and the AS at 14 weeks group (BPNDankle-AS-14W 12.212 ± 2.25; BPNDSJJ-AS-14W 13.389 ± 3.60) were significantly higher than the controls at 14 weeks group (BPNDankle-Ctr-14W 0.204 ± 0.16, BPNDSJJ-Ctr-14W 0.655 ± 0.35) respectively. The four groups had no significant difference in the [18F]FDG uptake of ankle and SIJ. IHC and IF staining revealed that the overexpression of P2X7R was colocalized with activated macrophages from the ankle synovium and spinal endplate in mice with AS, indicating that quantification of P2X7R may contribute to the understanding of the pathogenesis of inflammation in human AS.

CONCLUSION

This study developed a novel P2X7R-targeting PET tracer [18F]GSK1482160 to detect the expression of P2X7R in AS mouse models and provided powerful non-invasive PET imaging and quantification for AS.

Comparison of coronary artery bypass grafting and percutaneous coronary intervention for syphilitic coronary artery ostial lesions: A 4-year retrospective study

This study investigated the efficacy of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in treatment of patients with syphilitic coronary artery ostial lesions (SCAOL).Sixty SCAOL patients were divided into two groups according to the different treatments: the CABG group (n = 32) and the PCI group (n = 28). We determined serum levels of β-type natriuretic peptide (BNP) and cardiac function, and evaluated treatment efficacy such as the rates of restenosis, patency, and major adverse cardiovascular events (MACEs) during hospital stay and the effects of antisyphilis and different types of CABG on restenosis during the 6-month follow-up period.There were no statistical differences in demographic or baseline clinical characteristics, BNP levels, left ventricular end-diastolic diameter (LVDd), or ejection fraction (EF) between the CABG and PCI groups at 1 week after surgery, However, after 6-month of follow-up, the CABG group had a significantly lower rate of coronary artery restenosis, lower incidence of MACEs, and better cardiac function than the PCI group. Within the CABG group, the left internal mammary artery (LIMA) subgroup had a lower restenosis rate than the saphenous vein graft (SVG) subgroup. In addition, patients who had received anti-syphilis therapy had a significantly lower restenosis rate than those without anti-syphilis therapy at 6-month post-surgery.Compared with patients who received PCI, patients who received CABG had better prognoses. LIMA has a better therapeutic efficacy than SVG in terms of the restenosis rate, and anti-syphilis treatment significantly reduces the restenosis rate, compared with non-anti-syphilis treatment.

Usefulness of Positron Emission Tomography in Patients with Syphilis: A Systematic Review of Observational Studies

Background:

Diagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography (PET) in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis.

Methods:

We searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases (SinoMed, Wanfang, and CNKI) for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms “syphilis” and “positron emission tomography”. We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans.

Results:

Of 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ± 12.1 years. In primary syphilis, increased fluorodeoxyglucose (FDG) accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the asymmetry of radiotracer uptake.

Conclusion:

PET is helpful in targeting diagnostic interventions, characterizing disease extent, assessing nodal involvement, and treatment efficacy for syphilis.

Transient aortitis documented by positron emission tomography in a case series of men and transgender women infected with syphilis

OBJECTIVES

Syphilis infection persists globally contributing to preventable and treatable morbidity and mortality. How extensive early syphilis disseminates is unknown. To better understand the relationship between early syphilis infection and inflammation over time, our study enrolled six individuals recently infected with syphilis for sequential positron emission tomography (PET) scans.

METHODS

We evaluated a case series of six individuals with high syphilis titres (two secondary, two early latent and two latent, unknown duration, but with high titre) who received sequential PET scans to assess inflammation over time and its response to treatment.

RESULTS

At time of PET scan, four of the six individuals were co-infected with HIV. One of the four was not on antiretroviral therapy and three of the four were not virally suppressed (viral load of >400 copies/mL). Baseline rapid plasma reagin (RPR) titres ranged from 1:64 to 1:256 (four of the six participants had prior non-reactive RPR results). Five of the six participants had mild to intense hypermetabolic PET scan activity consistent with cervical (n=5), axillary (n=4), inguinal (n=5) and retroperitoneal (n=1) adenopathy. Mild hypermetabolic activity in the thoracic aortic wall, suggesting aortitis, was present among the same five participants and resolved within 30 days for four of the five participants and 60 days for the other participant. However, widespread lymphadenopathy remained present in PET scans up to 3 months following treatment in two participants. We did not find any abnormal PET scan activity of the central nervous system.

CONCLUSION

We found abnormal aortic wall PET scan activity suggesting aortitis to be common in a case series of patients with early syphilis. In research settings, PET scans may be a sensitive tool to monitor inflammation associated with syphilis.

A case report of CT-diagnosed renal infarct secondary to syphilitic aortitis

BACKGROUND

Even though reported cases of syphilis have been increasing, cases of tertiary syphilis remain extremely rare. The majority of our knowledge with regard to complications of syphilis such as aortitis was acquired before the advent of relatively modern technologies such as CT, MRI and PET. This case report presents a rare case of syphilitic aortitis associated with a renal infarct caused by a peripheral arterial embolism diagnosed by CT.

CASE PRESENTATION

We present a young man with sudden abdominal pain and flank tenderness without fever. Blood tests showed acute kidney failure. Computed tomography showed a right renal infarct and a non-circular thickening of the descending thoracic aortic wall with intra-luminal thrombus. Serology confirmed the diagnosis of syphilis. Treatment with anticoagulant and penicillin resulted in a good outcome. Follow-up PET-MRI showed resolution of the thrombus with a metabolically inactive atheromatous plaque.

CONCLUSION

Technologies, such as CT, PET-CT and PET-MRI, that were not present during the pre-antibiotic era, can provide new insights into rare presentations of tertiary syphilis such as aortitis. These imaging modalities show promise for early radiological diagnosis of aortitis in syphilis and may be useful for determining the response to treatment in specific cases.

Probable Syphilitic Aortitis Documented by Positron Emission Tomography

Positron emission tomography (PET) has been used to aid in diagnosis of inflammatory and infectious disease. We describe the case of a patient with early latent syphilis with increased metabolic activity along the aorta detected via PET, suggesting probable aortitis. Three months after treatment, the PET showed apparent resolution of the aortitis.

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.

The role of 18F-FDG PET/CT in large-vessel vasculitis: appropriateness of current classification criteria?

Patients with clinical suspicion of large-vessel vasculitis (LVV) may present with nonspecific signs and symptoms and increased inflammatory parameters and may remain without diagnosis after routine diagnostic procedures. Both the nonspecificity of the radiopharmaceutical ¹⁸F-FDG and the synergy of integrating functional and anatomical images with PET/CT offer substantial benefit in the diagnostic work-up of patients with clinical suspicion for LVV. A negative temporal artery biopsy, an ultrasonography without an arterial halo, or a MRI without aortic wall thickening or oedema do not exclude the presence of LVV and should therefore not exclude the use of ¹⁸F-FDG PET/CT when LVV is clinically suspected. This overview further discusses the notion that there is substantial underdiagnosis of LVV. Late diagnosis of LVV may lead to surgery or angioplasty in occlusive forms and is often accompanied by serious aortic complications and a fatal outcome. In contrast to the American College of Rheumatology 1990 criteria for vasculitis, based on late LVV effects like arterial stenosis and/or occlusion, ¹⁸F-FDG PET/CT sheds new light on the classification of giant cell arteritis (GCA) and Takayasu arteritis (TA). The combination of these observations makes the role of ¹⁸F-FDG PET/CT in the assessment of patients suspected for having LVV promising.