RESUMO
Incidental gastrointestinal tract (GIT) [18F]-Fluorodeoxyglucose (FDG) uptake in positron emission technology/computed tomography (PET/CT) is an unexpected and often complicated finding for clinicians. This retrospective study reviewed 8991 charts of patients who underwent PET/CT: 440 patients had incidental GIT uptake, of which 80 underwent endoscopy. Patient characteristics, imaging parameters, and endoscopic findings were studied. Of the 80 patients, 31 had cancer/pre-cancer lesions (16 carcinomas; 15 pre-malignant polyps). Compared to patients with benign/absent lesions, patients with cancer/pre-cancer lesions were significantly older (p = 0.01), underwent PET/CT for primary evaluation/staging of cancer (p = 0.03), had focal GIT uptake (p = 0.04), and had lower GIT uptake (p = 0.004). Among patients with focal uptake, an SUVmax of 9.2 had the highest sensitivity (0.76) and specificity (0.885) in detecting cancer/pre-cancerous lesions. Lower GIT uptake was most common in the sigmoid colon, and upper GIT uptake was most frequent in the stomach. In a bivariate analysis, predictors of cancer/pre-cancer were older age, PET/CT indicated for primary evaluation, focal uptake, uptake in the lower GIT, and higher SUVmax. Further endoscopic investigation is warranted for patients with incidental GIT uptake, especially in the elderly or those presenting for primary evaluation with PET/CT, with the following findings on imaging: lower GIT uptake, focal uptake, or high SUVmax.
RESUMO
Supine [18F]Fluorodeoxyglucose (FDG) positron emission technology/computed tomography (PET/CT) is a commonly used modality for the initial staging of breast cancer, and several previous studies have shown superior sensitivity and specificity of prone FDG PET/CT in comparison to its supine counterpart. This retrospective study included 25 females with breast cancer referred for staging. They underwent supine FDG PET/CT followed by prone FDG PET/CT. The outcomes were: number of primary breast lesions, anatomical site of FDG-avid lymph nodes (LNs), and number and type of bone lesions, with SUVmax of all corresponding parameters. Performance was superior in prone acquisition compared to supine acquisition, with the respective results: 29 vs. 22 breast tumor lesions detected, 62 vs. 27 FDG-avid axillary LNs detected, sensitivity of 68% vs. 57%, specificity of 64% vs. 53%. The detection rate of axillary LNs in the prone position was significantly higher (p = 0.001). SUVmax for breast tumor lesions (p = 0.000) and number of detected axillary LNs (p = 0.002) were significantly higher in prone acquisition. Five patients were upstaged after experts read the prone acquisition. Prone FDG PET/CT acquisition is a promising technique in detecting primary breast lesions and metastatic LNs possibly missed in supine acquisition, which may lead to change in patient staging and management.
RESUMO
Biochemical recurrence (BCR) of prostate cancer (PCa) occurs in about 25% of patients treated with radical prostatectomy (RP) and up to 45% in patients who receive external beam radiotherapy (RT). Early diagnosis of PCa recurrence is of high importance for successful salvage therapy. The aim of the present study is to analyze the efficacy of 68 Ga-PSMA PET/CT in detecting the presence of local and/or systemic disease in patients with a history of PCa who have BCR. A total of 52 PCa patients with BCR referred for 68 Ga-PSMA PET/CT were recruited from the American University of Beirut Medical Center between November 2017 and December 2019. We compared the performance of PSMA PET/CT to the results and clinical factors based on follow up: PSA, PSA kinetics, primary treatment, and Gleason score. The relationship between the PET/CT findings and clinical indicators of disease were assessed by univariate and multivariate logistic regression. From a total of 52 patients, 34 (65.4%) had positive PSMA-PET/CT scans. Among those, 8/34 (23.5%) received primary RT. For all patients with a positive PSMA-PET: the detection rate was 2/4 (50%) for PSA < 0.2, 5/10 (50%) for PSA 0.2-0.49, 3/6 (50%) for PSA 0.5-0.99, 6/12 (50%) for PSA 1-1.99, 8/9 (88.9%) for PSA 2-3.99, and 10/11 (90.9%) for PSA 4-10.PSMA-PET/CT positivity was significantly associated with PSA level at time of PET scan, PSA doubling time, Gleason score and TNM staging. However, it did not show a significant correlation with radiotherapy as primary treatment, ongoing androgen deprivation therapy (ADT), time to relapse, and initial PSA before therapy. In our single center prospective trial, 68 Ga-PSMA PET/CT successfully detected the recurrence of PCa in patients with BCR. Scan positivity was significantly associated with PSA level at time of PET scan, PSA doubling time, Gleason score, and TNM staging. PSMA- PET/CT is a highly promising modality in the work up of patients with PCa in the setting of BCR for earlier detection of disease recurrence.
