FDG PET/CT Imaging of Sarcoidosis Régis, Claudine; Benali, Khadija; Rouzet, François
Seminars in nuclear medicine,
March 2023, 2023-03-00, 20230301, Letnik:
53, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Sarcoidosis is a multisystemic granulomatous disease of unknown etiology. The diagnostic can be made by histological identification of non-caseous granuloma or by a combination of clinical criteria. ...Active inflammatory granuloma can lead to fibrotic damage. Although 50% of cases resolve spontaneously, systemic treatments are often necessary to decrease symptoms and avoid permanent organ dysfunction, notably in cardiac sarcoidosis. The course of the disease can be punctuated by exacerbations and relapses and the prognostic depends mainly on affected sites and patient management. FDG-PET/CT along with newer FDG-PET/MR have emerged as key imaging modalities in sarcoidosis, namely for certain diagnostic purposes, staging and biopsy guiding. By identifying with a high sensitivity inflammatory active granuloma, FDG hybrid imaging is a main prognostic tool and therapeutic ally in sarcoidosis. This review aims to highlight the actual critical roles of hybrid PET imaging in sarcoidosis and display a brief perspective for the future which appears to include other radiotracers and artificial intelligence applications.
Nuclear Imaging in Sarcoidosis Piekarski, Eve; Benali, Khadija; Rouzet, François
Seminars in nuclear medicine,
20/May , Letnik:
48, Številka:
3
Journal Article
Recenzirano
Sarcoidosis is a multisystem granulomatosis which may result in a wide variety of clinical and biological presentations. Symptoms are often nonspecific, and incidental abnormal findings on chest ...radiography is rather common. Although sarcoidosis resolves favorably in most cases, some localizations can provoke functional impairment or even impact on patients' prognosis. The diagnosis is based on a pathological hallmark which is the non-necrotizing epithelioid-cell rich granuloma.
Owing to the ability to detect inflammation throughout the body with a high sensibility, FDG-PET/CT gained a central role in sarcoidosis because it can suggest the diagnosis in certain clinical context, guide biopsy, evaluate the extent of the disease, help assess the prognosis, and monitor immunosuppressive therapy. This review will briefly describe clinical and typical findings of conventional imaging according to organ involvement, in order to highlight the additional information provided by nuclear imaging.
In the future, we can expect to further improve diagnostic performance of imaging in some indications through the availability of more specific radiopharmaceuticals and the wider use of combined PET/MRI.
This study aimed at determining the diagnostic implications of indirect signs of infection at FDG-PET—i.e., hypermetabolisms of the spleen and/or bone marrow (HSBM)—when documented in patients with ...known or suspected infective endocarditis (IE).
HSBM were defined by higher mean standardized uptake values comparatively to that of the liver on FDG-PET images from patients with a high likelihood of IE and prospectively included in a multicenter study.
Among the 129 included patients, IE was ultimately deemed as definite in 88 cases. HSBM was a predictor of definite IE (P = 0.014; odds ratio (OR) 3.2), independently of the criterion of an abnormal cardiac FDG uptake (P = 0.0007; OR 9.68), and a definite IE was documented in 97% (29/30) of patients showing both HSBM and abnormal cardiac uptake, 78% (7/9) of patients with only abnormal cardiac uptake, 67% (42/63) of patients with only HSBM, and 37% (10/27) of patients with neither one.
In this cohort with a high likelihood of IE, HSBM is an additional albeit indirect sign of IE, independently of the criterion of an abnormal cardiac uptake, and could reinforce the suspicion of IE in the absence of any other infectious, inflammatory, or malignant disease.
Our objective was to evaluate in patients with prosthetic valve endocarditis (PVE) treated conservatively, the prognostic value of white blood cell (WBC) signal intensity on SPECT and to describe the ...evolution of the WBC signal under antibiotics.
Patients with PVE treated conservatively and positive WBC-SPECT imaging were identified retrospectively. Signal intensity was classified as intense if equal to or higher, or mild if lower, than the liver signal. Clinical, biological, imaging and follow-up information were collected from medical files.
Among 47 patients, WBC signal was classified as intense in 10 patients and as mild, in 37. The incidence of the primary composite endpoint (death, late cardiac surgery, or relapse) was significantly higher in patients with intense vs. mild signal (90% vs. 11%). Twenty-five patients underwent a second WBC-SPECT imaging during follow-up. The prevalence of WBC signal decreased progressively from 89% between 3 and 6 weeks to 42% between 6 and 9 weeks and 8% more than 9 weeks after initiation of antibiotics.
In patients with PVE treated conservatively, intense WBC signal was associated with poor outcome. WBC-SPECT imaging appears as an interesting tool for risk stratification and to monitor locally the efficacy of antibiotic treatment.
The trade-off between resolution and count sensitivity dominates the performance of standard gamma cameras and dictates the need for relatively high doses of radioactivity of the used ...radiopharmaceuticals in order to limit image acquisition duration. The introduction of cadmium-zinc-telluride (CZT)-based cameras may overcome some of the limitations against conventional gamma cameras. CZT cameras used for the evaluation of myocardial perfusion have been shown to have a higher count sensitivity compared to conventional single photon emission computed tomography (SPECT) techniques. CZT image quality is further improved by the development of a dedicated three-dimensional iterative reconstruction algorithm, based on maximum likelihood expectation maximization (MLEM), which corrects for the loss in spatial resolution due to line response function of the collimator. All these innovations significantly reduce imaging time and result in a lower patient’s radiation exposure compared with standard SPECT. To guide current and possible future users of the CZT technique for myocardial perfusion imaging, the Cardiovascular Committee of the European Association of Nuclear Medicine, starting from the experience of its members, has decided to examine the current literature regarding procedures and clinical data on CZT cameras. The committee hereby aims 1) to identify the main acquisitions protocols; 2) to evaluate the diagnostic and prognostic value of CZT derived myocardial perfusion, and finally 3) to determine the impact of CZT on radiation exposure.
The diagnosis of infective endocarditis (IE) is challenging and requires the association of morphological features suggestive of valvular infection such as the presence of vegetations or abscesses ...identified usually with echocardiography and positive blood culture or serologies suggestive of systemic bacterial infection. In the past 5 years, several groups confirmed the incremental value of FDG-PET imaging and radiolabeled leukocyte scintigraphy over echocardiography for the diagnosis of IE. Based on the latter studies, the presence of abnormal activity in the perivalvular region on either FDG-PET imaging or radiolabeled leukocyte scintigraphy has been added as a major criterion for the diagnosis of IE in the guidelines recently published. Nuclear physicians should therefore learn not only the imaging criteria in favor of active IE but also the pitfalls of these nuclear imaging techniques in order to give a useful answer to the referring physician for the management of these patients. In fact, the diagnosis of IE is often complex and requires the integration of multiple clinical, biological, and imaging parameters. Multi-disciplinary teams including cardiologists, infectious disease physicians, cardiac surgeons, and radiologists have been therefore set up in several institutions to discuss the diagnosis and management of patients with a suspicion of IE. It is now time for nuclear cardiologists to join the team.
Abstract
Background
The 2023 Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) classification is a new diagnostic tool for infective endocarditis, updating the 2000 modified ...Duke and the 2015 European Society for Cardiology (ESC) classifications. In comparison, its sensitivity is higher; however, its specificity remains to be evaluated and compared to that of the 2 other classifications in endocarditis suspected patients.
Methods
We retrospectively collected the characteristics of patients hospitalized in Bichat University’s Hospital, Paris, in 2021, who had been evaluated for clinical suspicion of endocarditis, have had at least a transthoracic echocardiography, 2 pairs of blood cultures, 3-month follow-up and in whom endocarditis diagnosis was finally rejected. All patients were classified by 2000 modified Duke, 2015 ESC and 2023 Duke-ISCVID, as though the endocarditis diagnosis had not been rejected.
Results
In total, 130 patients’ charts were analyzed. Mean age was 62 years, 84 (64.6%) were male, 39 (30.0%) had prosthetic cardiac valve or valve repair, 21 (16.2%) cardiac implanted electronic device, and 30 (23.1%) other cardiac conditions. Overall, 5, 2, and 5 patients were falsely classified as definite endocarditis with the 2000 modified Duke, 2015 ESC, and 2023 Duke-ISCVID classifications, respectively. The corresponding specificities were 96.2% (95% confidence interval CI 90.8%, 98.6%), 98.5% (95% CI 93.9%, 99.7%), and 96.2% (95% CI 90.8%, 98.6%). The rates of possible endocarditis were of 38%, 35%, and 35% in the 3 classifications, respectively.
Conclusions
The 2023 Duke-ISCVID classification is highly specific for ruling out the diagnosis of definite infective endocarditis in patients who had been evaluated for IE.
In a population of patients suspected of EI for whom the diagnosis was finally rejected, the 2023 Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) classification presents with an excellent specificity.
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