[Diagnostic value of 18F-FDG PET/CT in fever of unknown origin]. / A 18F-FDG-PET/CT helye az ismeretlen eredetu láz diagnosztikai algoritmusában.

Fever of unknown origin is a common differential diagnostic problem in medicine. More than 60 years have passed since the first established definition of the disease, and despite constant development and improvement of diagnostic procedures, the differential diagnosis and choosing adequate therapy still remains a challenge in this patient population. The medical literature lists at least 200 diseases that may manifest with fever of unknown origin, and it encompasses a wide clinical spectrum. This symptom is present in approximately 1.5-3% of hospitalized patients. In recent decades, not only the concept of fever of unknown origin has changed several times, but the recommended differential diagnostic procedures as well. Positron emission tomography is one of the latest imaging procedures that also contributes to establishing the correct diagnosis. The purpose of this publication is to provide an overview of different diseases which might cause fever of unknown origin, and the most frequently used diagnostic algorithms, moreover to highlight the importance of positron emission tomography in the evaluation of the aetiology of fever of unknown origin. Orv Hetil. 2022; 163(49): 1935-1942.

[Cyclic Cushings syndrome: a case study and overview]. / Cyklický Cushingov syndróm: kazuistika a prehlad.

Cushings syndrome and especially Cushing´s disease represent diagnostically and therapeutically complicated medical situations. In some patients, cyclic changes in cortisol production additionally hamper the diagnosis in terms of source identification and management of hormone overproduction. It may not be clear, whether the patient is cured or not even years after the treatment. It is a rare disorder variant, but we assume that it is underdiagnosed and it´s incidence is actually higher. The article deals with a complicated course of diagnosis and treatment in a patient with cyclic Cushings syndrome.Key words: Cushing´s disease - cyclic Cushing´s syndrome - hypercortisolism.

FDG-PET in the Erdheim-Chester disease: its diagnostic and follow-up role.

A 62-year-old man presented with diabetes insipidus, pulmonary fibrosis, right atrial tumor and bilateral knee osteoarthritis with cystic lesions of distal femur and proximal tibia. Scintigraphy and histological examination of right femur bone biopsy revealed changes characterized for Paget's disease. Re-evaluation of the computer tomography (CT) scans and histological samples revealed diffuse infiltrates of foamy histiocytes in the bone marrow what was consistent with Erdheim-Chester disease. Positron emission tomography/computed tomography (PET/CT) was performed to access the activity and extent of disease.

FDG-PET/CT in large-vessel vasculitis: its diagnostic and follow-up role.

Vasculitis is a disorder characterized by inflammation of blood vessels. Its clinical manifestations are diverse and depend on the size of the involved vessels and the organs affected by ischemia. In some cases the disease is manifested only with symptoms and signs of systemic inflammation (e.g. fever, night sweats, fatigue). Results of laboratory tests usually indicate only the inflammatory process. It is known that radiolabeled glucose analogue 18F-fluoro-deoxyglucose ([18F] FDG) used in positron emission tomography (PET) accumulates in both malignant and inflammatory tissue (Zhuang et al. in Radiol Clin North Am 43:121-134, 2005). We report a case of a patient with FDG-PET/CT findings of large-vessel vasculitis with follow-up results that convinced us to change the treatment.

Impact of mediastinal, liver and lung (123)I-metaiodobenzylguanidine ( (123)I-MIBG) washout on calculated (123)I-MIBG myocardial washout.

PURPOSE: In planar (123)I-metaiodobenzylguanidine ((123)I-MIBG) myocardial imaging mediastinum (M) activity is often used as a background correction in calculating "washout" (WO). However, the most likely sources for counts that might produce errors in estimating myocardial (Myo) activity are lung (Lu) and liver (Li), which typically have higher counts/pixel (cpp) than M. The present study investigated the relationship between changes in Lu, Li and Myo activity between early and late planar (123)I-MIBG images, with comparison to M as the best estimator of non-specific background activity. METHODS: Studies on 98 subjects with both early (e) and late (l) planar (123)I-MIBG images were analysed. There were 68 subjects with chronic heart failure (CHF), 14 with hypertension (HTN) but no known heart disease and 16 controls (C). For each image, regions of interest (ROIs) were drawn: an irregular whole Myo, Lu, upper M and Li. For each ROI, WO was calculated as [(cpp(e)-cpp(l:decay corrected))/cpp(e)]x100%. RESULTS: Multivariable forward stepwise regression analysis showed that overall a significant proportion of the variation in Myo WO could be explained by a model containing M WO and Lu WO (37%, p < 0.001). Only in controls was M WO the sole variable explaining a significant proportion of the variation in Myo WO (27%, p = 0.023). CONCLUSION: Although increased Myo WO in CHF subjects reflects disease severity, part of the count differences measured on planar (123)I-MIBG myocardial images likely reflects changes in the adjacent and surrounding Lu tissue. The results for the controls suggest that this is the only group where a mediastinum correction alone may be appropriate for cardiac WO calculations.

I-123-mIBG myocardial imaging for assessment of risk for a major cardiac event in heart failure patients: insights from a retrospective European multicenter study.

PURPOSE: Single-center experiences have shown that myocardial meta-iodobenzylguanidine (mIBG) uptake has prognostic value in heart failure (HF) patients. To verify these observations using a rigorous clinical trial methodology, a retrospective review and prospective quantitative reanalysis was performed on a series of cardiac (123)I-mIBG scans acquired during a 10-year period at six centers in Europe. METHODS: (123)I-mIBG scans obtained on 290 HF patients [(262 with left ventricular ejection fraction (LVEF) < 50%)] from 1993 to 2002 were reanalyzed using a standardized methodology to determine the heart-to-mediastinum ratio (H/M) on delayed planar images. All image results were verified by three independent reviewers. Major cardiac events [MCEs; cardiac death, cardiac transplant, potentially fatal arrhythmia (including implantable cardioverter-defibrillator discharge)] during 24-month follow-up were confirmed by an adjudication committee. RESULTS: MCEs occurred in 67 patients (26%): mean H/M ratio was 1.51 +/- 0.30 for the MCE group and 1.97 +/- 0.54 for the non-MCE group (p < 0.001). Two-year event-free survival using an optimum H/M ratio threshold of 1.75 was 62% for H/M ratio less than 1.75, 95% for H/M ratio greater than or equal to 1.75 (p < 0.0001). Logistic regression showed H/M ratio and LVEF as the only significant predictors of MCE. Using the lower and upper H/M quartiles of 1.45 and 2.17 as high- and very low-risk thresholds, 2-year event-free survival rates were 52% and 98%, respectively. Among patients with LVEF < or = 35% and H/M > or = 1.75 (n = 73), there were nine MCEs because of progressive HF and only one because of an arrhythmia. CONCLUSION: Application of a clinical trial methodology via the retrospective reanalysis of (123)I-mIBG images confirms the previously reported prognostic value of this method in HF patients, including potential identification of a quantitative threshold for low risk for cardiac mortality and potentially fatal ventricular arrhythmias.