M.J. Pérez-Castejón

[Meta-analysis of the diagnostic performance of 18F-FDG PET in renal cell carcinoma].

AIM Renal cell carcinoma is the most frequent solid kidney tumor. At present, PET is not the imaging test of choice, the helical CT being the best method to assess these patients. The aim of the study was to perform a meta-analysis of the literature to evaluate the performance and accuracy of 18F-FDG PET in the detection of primary disease, recurrence and metastasis of renal cell carcinoma. MATERIALS AND METHODS A systematic search was done of the available literature in primary and secondary databases published until October 2004 indexed in MEDLINE and CANCERLIT. Exclusion/inclusion criteria were applied. Their quality was evaluated using the Flynn criteria and joint estimators of sensitivity (S), specificity (Sp), likelihood ratios (LR), diagnostic odds ratio (DOR) and summary ROC (SROC) curve were obtained. The presence of the threshold effect was evaluated and the summary ROC (SROC) curve was calculated. RESULTS Seven out of 46 studies fulfilled the inclusion criteria and were analyzed. Three studies evaluated the use of 18F-FDG PET in the differential diagnosis of renal masses. Two studies analyzed restaging and two analyzed the role of 18F-FDG PET in the detection of metastatic disease. All the selected studies were classified according to Flynns criteria. We found the highest S in restaging with S 0.87 (95 % CI, 0.75-0.95) and in metastases detection with S 0.72 (95 % CI, 0.56-0.85) as well as the high Sp in differential diagnosis of renal masses. CONCLUSIONS The results of this meta-analysis suggest that 18F-FDG PET can be useful in restaging and detection of metastatic disease, based on its acceptable S and Sp. However, the performance of 18F-FDG PET in the detection of primary disease is limited, but this may improve with the new PET/CT systems.

Assessment of the diagnostic accuracy of 18 F-FDG PET/CT in prosthetic infective endocarditis and cardiac implantable electronic device infection: comparison of different interpretation criteria

PurposeThe diagnosis of prosthetic valve (PV) infective endocarditis (IE) and infection of cardiac implantable electronic devices (CIEDs) remains challenging. The aim of this study was to assess the usefulness of 18F-FDG PET/CT in these patients and analyse the interpretation criteria.MethodsWe included 41 patients suspected of having IE by the Duke criteria who underwent 18F-FDG PET/CT. The criteria applied for classifying the findings as positive/negative for IE were: (a) visual analysis of only PET images with attenuation-correction (AC PET images); (b) visual analysis of both AC PET images and PET images without AC (NAC PET images); (c) qualitative analysis of NAC PET images; and (d) semiquantitative analysis of AC PET images. 18F-FDG PET/CT was considered positive for IE independently of the intensity and distribution of FDG uptake. The gold standard was the Duke pathological criteria (if tissue was available) or the decision of an endocarditis expert team after a minimum 4 months follow-up.ResultsWe studied 62 areas with suspicion of IE, 28 areas (45 %) showing definite IE and 34 (55 %) showing possible IE. Visual analysis of only AC PET images showed poor diagnostic accuracy (sensitivity 20 %, specificity 57 %). Visual analysis of both AC PET and NAC PET images showed excellent sensitivity (100 %) and intermediate specificity (73 %), focal uptake being more frequently associated with IE. The accuracy of qualitative analysis of NAC PET images depended on the threshold: the maximum sensitivity, specificity and accuracy achieved were 88 %, 80 %, 84 %, respectively. In the semiquantitative analysis of AC PET images, SUVmax was higher in areas of confirmed IE than in those without IE (∆SUVmax 2.2, p < 0.001). When FDG uptake was twice that in the liver, IE was always confirmed, and SUVmax 5.5 was the optimal threshold for IE diagnosis using ROC curve analysis (area under the curve 0.71).ConclusionThe value of 18F-FDG PET/CT in the diagnosis of suspected IE of PVs and CIEDs is highly dependent on patient preparation and the method used for image interpretation. Based on our results, the best method is to consider a study positive for IE when FDG uptake is present in both AC PET and NAC PET images.

Technetium-99m tetrofosmin rest/stress myocardial SPET with a same-day 2-hour protocol: comparison with coronary angiography. A Spanish-Portuguese multicentre clinical trial

Technetium-99m tetrofosmin (Myoview) has unique properties for myocardial perfusion imaging very early after injection of the tracer. We used a very short same-day rest/stress protocol, to be performed within 2 h and evaluated its diagnostic accuracy. The study included 144 patients from seven Spanish and four Portuguese centres with a diagnosis of uncomplicated coronary artery disease (CAD); 78 patients (54%) had no history of prior myocardial infarction. Patients were injected with ≤300 MBq99mTc-tetrofosmin at rest and ≤900 MBq approximately 1 h later at peak exercise. Single-photon emission tomographic (SPET) acquisitions were initiated within 5–30 min post injection. The results were compared with those of coronary angiography (CA). The data of 142 patients were completely evaluable (two with non-evaluable images were excluded). The quality of rest images was excellent or good in 86%, regionally problematic in 7%, poor but well interpretable in 5% and non-evaluable in 2%. The overall sensitivity for the detection of CAD was 93%, the specificity 38% and the accuracy 85%. The localization of defects by SPET in relation to the perfusion territories of stenosed vessels (≽50%) was achieved with a sensitivity of 64% for the left anterior descending artery, 49% for the left circumflex artery and 86% for the right coronary artery, and an accuracy of 71%, 72% and 73% respectively. Concordance of SPET and CA was 62% for single-vessel disease and 68% for multivessel disease. In conclusion, this Spanish-Portuguese multicentre clinical trial confirmed, in a considerable number of patients who underwent coronary angiography, the feasibility of99mTc tetrofosmin (Myoview) rest/stress myocardial SPET using a very short protocol (2 h).

Impacto de la tomografía por emisión de positrones mediante 18-Fluoro-2-Desoxi-D-Glucosa (PET-FDG) en el manejo terapéutico de pacientes con recurrencia secundaria a cáncer de ovario

Resumen Objetivo La deteccion de la recurrencia secundaria a cancer de ovario es un problema de importancia notoria, pudiendo mediante un diagnostico correcto ofrecer alternativas utiles en el manejo de las pacientes. El objetivo de este estudio ha sido valorar el impacto terapeutico de la PET-FDG en la recurrencia por cancer de ovario. Material y metodos Se han incluido 43 enfermas con cancer de ovario en las que se efectuo el estudio PET-FDG ante la sospecha diagnostica de recidiva. Los resultados de la PET-FDG se confirmaron por histopatologia y seguimiento clinico mayor de 12 meses. Se ha comparado el impacto en el manejo de las pacientes basado en los metodos convencionales de imagen, con el plan de tratamiento considerando los hallazgos de la PET-FDG, clasificando el impacto de la PET-FDG como alto, medio, bajo o no impacto. Los cambios en el manejo terapeutico de las enfermas, han sido clasificados como intermodalidad o intramodalidad. Resultados El estudio PET-FDG obtuvo un impacto alto en el manejo terapeutico de 28 pacientes (65,1 %), un impacto medio en 2 pacientes (4,6 %), un impacto bajo en 9 pacientes (20,9 %), y no tuvo impacto en 4 enfermas (9,3 %). La PET-FDG indujo un cambio intermodalidad en 27 pacientes (62,8 %); un cambio intramodalidad en 3 pacientes (7 %); y finalmente en 13 enfermas (30,2 %), no produjo ningun cambio en el tratamiento. Conclusiones La PET-FDG proporciona una informacion adicional con respecto a los metodos diagnosticos de imagen convencional, permitiendo efectuar cambios en el manejo terapeutico en la mayoria de las enfermas.

Pancreatic involvement detected with 18F-FDG PET/CT in disseminated sarcoidosis

La sarcoidosis is a granulomatous disease of unknown etiology. It may mimic malignancy and may affect multiple organs, with a variable clinical course. Pancreatic involvement is very rare. We present the case of a 78-year-old woman with systemic sarcoidosis whose (18)F-FDG PET/CT scan showed a pancreatic lesion and multiple lymphatic (thoracic and non-thoracic) and visceral lesions. The abnormal (18)F-FDG uptake in the pancreas was limited to the tail. A second (18)F-FDG PET/CT study performed 4 months and 3 weeks after the first PET/CT, following corticosteroid therapy during three and a half months, evidenced partial regression of the disease, with persistent (18)F-FDG pathological uptake in the pancreatic lesion.

Usefulness of 18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Infective Endocarditis in Daily Practice

Positron emission tomography/computed tomography (PET/CT) is helpful in prosthetic valve (PV) infective endocarditis (IE), but its usefulness in other settings is less established [(1)][1]. We aim to evaluate the yield of PET/CT in patients with suspicion of IE in 3 scenarios: PV, native valves (NV

Diagnosis of infection in a patient with implantable device with 18F-FDG PET-CT

We report the case of a 19-year-old woman with a bicameral implantable cardioverter defibrillator. Six months later, she complainted of local discomfort, swelling and pain in the sternotomy scar, without erythema, drainage or fever. She was referred to the Nuclear Medicine Department for evaluation of an inflammatoryinfectious process. An 18F-FDG PET-CT was performed, showing intense uptake in the generator pocket, along the path of the subcutaneous electrode and the deepest portion of extracardiac electrode. No pathological intracardiac uptake in the electrode and valves were observed. Since the metal may cause artefacts in the PET due to overcorrection, we compared the corrected and the uncorrected images, observing persistence of the uptake with similar intensity to those displayed in the corrected PET image; compatible with active inflammatory-infectious disease in the bag and the electrodes, discarding endovascular and valvular infection. The generator and the two electrodes were explanted and a new device was implanted. Cultures of the explanted electrodes and the bag’s tissue showed growth of Staphylococcus epidermidis and Propionibacterium acnes, confirming local infection of the removed material, consistent with the findings of PET-CT.