The role of 18FDG PET/CT imaging of aortic atherosclerosis: prospective study and technique optimization

Abstract Background Atherosclerosis is an inflammatory disease of the inner wall of large and medium-sized arteries. The progress of atherosclerosis based on a lot of factors, including systemic involvement of disease, the precise vascular arterial affection, and the degree of flow obstruction. We aim in this study to estimate the FDG uptake of the aortic wall in the early and delayed imaging and to correlate this with the morphologic changes detected by CT. Results This is a prospective study that was performed through 1 year. The study included 50 patients [30 males (60%) and 20 females (40%)] with male to female mean ratio 1.5:1 and their mean age 58.3 ± 15.7 years. Each patient underwent dual time-point 18F-FDG PET CT imaging at ~ 60 min (Early images) and 180 min (delayed images) after the administration of 18F-FDG. For each patient, the global 18F-FDG uptake in the aorta was determined by manually drawing regions of interest (ROIs) around the outer part of the arterial wall on every slice of the attenuation-corrected transverse PET CT images. Per-patient, per-time-point, per-vessel, and per-ROI radiotracer decay-corrected and body weight-corrected SUVs were calculated, resulting in a single mean value of maximum SUV for the aorta. The aortic wall FDG uptake was measured in both early and delayed images and expressed in terms of SUVmax. Then Retention index percentage of the aorta was measured. The retention index percentage was calculated by subtracting the SUVmax in early images from the SUVmax in delayed images and dividing by SUVmax in early images. Conclusion Aortic wall FDG uptake can be used as an additional parameter as well as a biomarker on evaluation of the arterial atherosclerotic activity. Delayed post 3 h FDG imaging is more accurate than the routine early post 1 h imaging in evaluating the atherosclerotic activity. </jats:sec

Diagnostic role of 18F-FDG PET/CT in recurrence detection of surgically treated gastric cancer: a cross-sectional study

Abstract Background Radical surgery of gastric cancer is considered as the only curative treatment; however, its poor long-term survival is often occurred due to its recurrence either local and/or distant metastasis. Thus, early detection of recurrence helps in improving the prognosis. Our aim is to assess the diagnostic role of 18F-FDG PET/CT for detecting postoperative recurrence in gastric cancer patients who have a radiological and/or clinical suspicion of recurrence. Results The study was carried over 31 males (62%) and 19 females (38%) pathologically proven with gastric carcinoma and underwent surgical intervention. All patients underwent PET/CT scan where the site and number of positive FDG activity analyzed. The sensitivity, specificity, and accuracy for locoregional recurrence were 75%, 81.58%, and 85% with p value 0.001; for regional lymph node recurrence were 100%, 100%, and 100% with p value &lt; 0.001; for liver metastasis were 100%, 100%, and 100% with p value &lt; 0.001; for peritoneum metastasis were 100%, 97.38%, and 98% with p value &lt; 0.001; and for distant metastasis were 100%, 85.7%, and 94% with p value &lt; 0.001. Conclusion With agreements to many studies, this study confirms that FDG PET/CT is a highly effective modality for postoperative surveillance detection of recurrent gastric cancer, especially in patients with clinically manifested disease, elevated tumor markers, and an indication of distant metastasis at diagnostic CT. </jats:sec

Value of 18-F-FDG PET/CT in assessment of patients with fever of unknown origin

Aim: To evaluate the value of 18F-FDG (positron emission tomography) PET/CT in assessment patients with fever of unknown origin (FUO) and to compare the findings with the results of the other investigations. Patients and methods: This is perspective study in which 27 patients having FUO underwent 18F-FDG-PET/CT examination, using combined PET/CT with contrast enhanced CT. PET/CT findings were compared with the results of biopsies, immunology, or microbiology around the examination period & for the following 3 month duration, during which patients with negative PET/CT findings were followed also. Results: The cause of FUO was explained according to the PET/CT findings and the other investigations in 27 patients: 6 patients with infections, 2 patients with autoimmune inflammation, 3 patients with solid malignancies, 2 patients with sarcoidosis, 6 patients with vasculitis, 5 patients with lymphoproliferative disease & 3 patients with negative findings. PET/CT findings matched the clinical diagnosis in 23 patients, 4 patients showed negative PET/CT findings (2 patients as true negative & the other 2 patients as false negative that were fatherly diagnosed as lymphoma). The examination sensitivity 95%, specificity 67%. Conclusion: 18F-FDG PET/CT can be a useful tool for scanning the whole body to suggest the FUO cause