Dual-Time-Point 18F-FDG PET/CT in Infective Endocarditis: Impact of Delayed Imaging in the Definitive Diagnosis of Endocarditis.

Infective endocarditis (IE) is a major public health condition due to the associated high morbidity and mortality. Our objective was to evaluate the utility of dual-time 2-deoxy-2-[18F] fluoro-D-glucose (18F-FDG) Positron Emission Tomography/Computed Tomography (PET/CT) imaging in the diagnosis of active IE in patients with suspected native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE). For this purpose, a retrospective study was carried out, including patients suspicious of NVE or PVE who underwent a dual-time-point 18F-FDG PET/CT. A final diagnosis was established by the Endocarditis Team after patient follow-up using all the available findings. Sixty-nine patients were assessed. A final diagnosis of NVE was established in 3 patients of the 34 by 18F-FDG PET/CT and in the case of PVE was established in 20 patients of the 35. A statistically significant association was found when evaluating the association between PET diagnosis at early acquisition and final diagnosis of IE (χ2 = 30.198, p < 0.001) and PET diagnosis at delayed acquisition for final diagnosis of IE (χ2 = 9.412, p = 0.002). Delayed PET/CT imaging determined the IE diagnosis in 16/58 of the studies. In conclusion, delayed 18F-FDG PET/CT imaging seems to be useful in improving the definitive diagnosis of IE.

Neuroendocrine Tumor Presented With Axillary Mass: A Case Report.

ABSTRACT: A 79-year-old man presented with a palpable left axillary mass and ultrasonography findings of conglomerate lymph nodes. The initial clinical suspicion was a lymphoproliferative disorder, but histopathological results revealed a grade 3 neuroendocrine tumor. The mass showed somatostatin receptor overexpression in 99m Tc-HYNIC-TOC scintigraphy and high uptake in 18 F-FDG PET/CT. Bilateral hypermetabolic adrenal nodes suggestive of metastases were also detected. The patient was treated with chemotherapy and immunotherapy, and PET/CT scan showed a partial metabolic response after 4 cycles. According to this case, neuroendocrine tumor should be considered in the differential diagnosis of axillary masses.

The Potential Utility of 18 F-FDG PET/CT in Monitoring Corticosteroid Therapy in Inflammatory Pseudotumor.

ABSTRACT: A 69-year-old man with suspected gastrointestinal stromal tumor was referred to 18 F-FDG PET/CT. Images showed increased metabolism in a jejunal wall thickening, 2 liver lesions, and hepatic lymph nodes. The patient underwent wedge biopsy of the liver, which revealed inflammatory pseudotumor. The patient was treated with 20 mg/d prednisone, with a gradual dose reduction. A partial metabolic response was achieved after 2 months of therapy, and a final PET/CT showed complete metabolic response after 9 months. This clinical case shows the potential role of PET/CT in the assessment of the response of the inflammatory pseudotumor to corticosteroid therapy.

18 F-FDG PET/CT to Spare Malignancy in a Rare Case of Lung Endometriosis.

ABSTRACT: Lung endometriosis is a rare condition. A 44-year-old woman with known lung endometriosis and radiological follow-up showed progression of bilateral lung affection at control CT, with an enlarged solid nodule with respect to previous control. 18 F-FDG PET/CT was performed to assess that lesion and to guide biopsy. PET images showed the multiple known nodules with pathological tracer uptake.

Correlation of Global and Regional Amyloid Burden by 18 F-Florbetaben PET/CT With Cognitive Impairment Profile and Severity.

PURPOSE: To assess the correlation between profile and severity deterioration in the neuropsychological assessment and the most affected regions in amyloid PET semiquantification. The influence of vascular risk and other potential confounding factors was also evaluated. METHODS: A retrospective, observational, and multicenter study including all patients referred for amyloid PET in daily practice was conducted. Patients underwent neuropsychological assessment, and cognitive decline severity and domain(s) affected were recorded. The patients were grouped according to cognitive impairment (CI) profile and severity: (A) no CI, single-domain amnestic CI, multiple-domain amnestic CI, and nonamnestic CI; and (B) mild CI, moderate and severe dementia. An adapted Framingham Stroke Risk Profile was calculated for each individual. Depression and parkinsonism were also recorded. Standardized quantitative analysis software was used to obtain standardized uptake value ratio (SUVR) values from PET/CT images. The corresponding associations were assessed with the most appropriate statistical tests. RESULTS: One hundred twenty-nine patients were included (62 men, 67 women; 64.67 ± 7.47 years old). Significant differences in global and regional amyloid load were exclusively found in women between non-CI and moderate dementia ( P = 0.006, for total-cerebellum SUVR). Posterior and anterior cingulates and prefrontal cortex best represented CI severity ( P = 0.003, 0.006, and 0.006, respectively). No relationship between the CI profile and the regional amyloid load was shown. A significantly high positive correlation was found between age and vascular risk and between these variables and amyloid load in nearly all regions, especially in women with moderate dementia. CONCLUSION: Semiquantitative analysis of amyloid PET by SUVR values revealed a significant correlation between amyloid burden and CI severity, although only in women.

Increasing the confidence of 18F-Florbetaben PET interpretations: Machine learning quantitative approximation.

AIM: To assess the added value of semiquantitative parameters on the visual assessment and to study the patterns of 18F-Florbetaben brain deposition. MATERIALS AND METHODS: Retrospective analysis of multicenter study performed in patients with mild cognitive impairment or dementia of uncertain origin. 18F-Florbetaben PET scans were visually interpreted by two experienced observers, analyzing target regions in order to calculate the interobserver agreement. Semiquantification of all cortical regions with respect to three reference regions was performed to obtain standardized uptake value ratios (SUVRs). The ability of SUVRs to predict the visual evaluation, the possibility of preferential radiotracer deposition in some target regions and interhemisphere differences were analyzed. RESULTS: 135 patients were evaluated. In the visual assessment, 72 were classified as positive. Interobserver agreement was excellent. All SUVRs were significantly higher in positive PET scans than in negative ones. Prefrontal area and posterior cingulate were the cortical regions with the best correlations with the visual evaluation, followed by the composite region. Using ROC analysis, the SUVRs obtained in same target locations showed the best diagnostic performance. CONCLUSIONS: The derived information from target regions seems to help the visual classification, based on a preferential amyloid ß deposit, allowing machine learning. The amyloid ß deposit, although diffuse in all cortical regions, seems not to be uniform and symmetric.

Response assessment of colorectal liver metastases with contrast enhanced CT/18F-FDG PET.

PURPOSE: Evaluate the diagnostic performance of contrast enhanced CT/PET (ceCT/PET) in the response assessment of patients with colorectal cancer liver metastases. METHODS: 33 ce CT/PET studies of 19 patients with colorectal liver metastases were prospectively evaluated. All of them, 13 (68.4%) were males and 6 (31.6%) females. Mean age and range were 63 [42-78]. All patients were treated with neoadjuvant chemotherapy. In all cases post-therapy diagnostic confirmation of liver lesions was obtained. A ce CT PET/was obtained 1h after the injection of 370 MBq of 18F-FDG. Metabolic and morphologic studies were evaluated by two blinded nuclear physicians and radiologists respectively to assess the location, size and suspected diagnosis of lesions (benign or malignant). A combined assessment of both techniques was performed. The final diagnosis was established by histopathology or clinical/radiological follow-up greater than 6 months. RESULTS: A total of 120 liver lesions were identified, 115 were malignant and 5 benign. From the malignant lesions, 105 were identified with the ceCT, 44 with the PET and 109 with ceCT/PET. All of the benign lesions were correctly classified with any of the three imaging techniques. The sensitivity of PET, ceCT and ceCT/PET were of 38%, 91% and 95% respectively and the specificity was 100% in all three of the diagnostic studies. CONCLUSION: Administration of intravenous contrast in the PET/CT is mandatory to evaluate treatment response rate of liver metastases due to the limitations of isolated metabolic images in these cases.

[Usefulness of (18)F-fluorodeoxyglucose-positron emission tomography-computerized tomography in the identification of the primary tumor in patients with cancer of unknown origin]. / Utilidad de la tomografía por emisión de positrones con (18)F-fluorodesoxiglucosa-tomografía computarizada en la identificación del tumor primario en pacientes con cáncer de origen desconocido.

BACKGROUND AND OBJECTIVE: We determined the utility of the (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)-computerized tomography (CT) in the localization of the primary tumor in patients with tumor of unknown origin (TUO). PATIENTS AND METHOD: (18)F-FDG PET-CT scans, performed between November 2006 and November 2010, in search for the primary tumor in patients with TUO, were retrospectively evaluated. Patients underwent a standard PET-CT, 50-60minutes after intravenous injection of 296-370MBq (18)F-FDG. PET-CT studies were assessed as pathological, with/without identification of the primary tumour and no pathological. Final diagnosis was established by histological confirmation and/or clinical/radiologic follow-up longer than 6 months. RESULTS: We studied 74 patients (59 males, 15 females), with ages ranging from 41-89 years. In 38 (51%) patients the PET-CT assessed the correct origin of the primary tumour. In 8 cases, a histological confirmation in the primary lesion was obtained. In 4 patients the PET-CT showed a false positive result. CONCLUSION: PET-CT scanning identified 51% of the primary sites in our sample of patients.

123-I ioflupane (Datscan®) presynaptic nigrostriatal imaging in patients with movement disorders

123-I Ioflupane (Datscan®) presynaptic imaging has been shown to have a significant utility in the assessment of patients with movement disorders 123-I Ioflupane SPECT is able to distinguish between ParkinsonÆs disease (PD) and other forms of parkinsonism without degeneration of the nigrostriatal pathway, including a common movement disorder such as essential tremor, and to assess disease progression in PD and other neurodegenerative disorders involving the substantia nigra.

A imagem pré-sináptica através de 123-I Ioflupane (Datscan®) tem mostrado um papel significante na avaliação de pacientes com distúrbios do movimento. 123-I Ioflupane SPECT é capaz de distinguir entre Mal de Parkinson (MP) e outras formas de parkinsonismo sem degenerações da via nigroestriatal incluindo um distúrbio comum de movimento parecido com o tremor essencial e para medir a evolução da doença no Mal de Parkinson e outros distúrbios neurodegenerativos envolvendo a substantia nigra.