ABDOMINAL IMAGINGORIGINAL ARTICLE PURPOSE The aim of this study was to retrospectively assess the correlation between minimum apparent diffusion coefficient (ADC min ) values obtained from diffusion-weighted magnetic resonance imaging (MRI) and maximum standardized uptake values (SUV max ) obtained from positron emission tomography-computed tomography (PET-CT) in rectal cancer. MATERIALS AND METHODSForty-one patients with pathologically confirmed rectal adenocarcinoma were included in this study. For preoperative staging, PET-CT and pelvic MRI with diffusion-weighted imaging were performed within one week (mean time interval, 3±1 day). For ADC measurements, the region of interest (ROI) was manually drawn along the border of each hyperintense tumor on b=1000 s/mm 2 images. After repeating this procedure on each consecutive tumor-containing slice to cover the entire tumoral area, ROIs were copied to ADC maps. ADC min was determined as the lowest ADC value among all ROIs in each tumor. For SUV max measurements, whole-body images were assessed visually on transaxial, sagittal, and coronal images. ROIs were determined from the lesions observed on each slice, and SUV max values were calculated automatically. The mean values of ADC min and SUV max were compared using Spearman's test. RESULTSThe mean ADC min was 0.62±0.19×10 -3 mm 2 /s (range, 0.368-1.227×10 -3 mm 2 /s), the mean SUV max was 20.07±9.3 (range, 4.3-49.5). A significant negative correlation was found between ADC min and SUV max (r=-0.347; P = 0.026). CONCLUSIONThere was a significant negative correlation between the ADC min and SUV max values in rectal adenocarcinomas. D iffusion-weighted imaging (DWI) is a widely used technique for disease evaluation in oncology (1, 2). In rectal cancer, the applications of DWI include tumor detection, tumor characterization, distinguishing tumor tissue from nontumor tissue, and monitoring and predicting treatment response (3-8). For local staging of rectal cancer, adding DWI to conventional magnetic resonance imaging (MRI) yields better identification of tumor borders and locoregional lymph nodes than conventional MRI alone (9, 10).The apparent diffusion coefficient (ADC) map obtained from DWI shows the freedom of water diffusion, and values calculated on the map are useful parameters in tissue characterization. By performing diffusion-weighted (DW) MRI with at least two diffusion weightings, or b values, the differential signal attenuation at different b values can be used to calculate the ADC (2). Regardless of the tumor type and location, the ADC values reflect tumor morphology, including the cellular density, integrity of cell membrane, and nuclear-to-cytoplasm ratio (11,12).Positron emission tomography/computed tomography (PET-CT) has become a crucial method in cancer imaging, both for diagnosis and staging, as well as for offering prognostic information based on tumor response. In PET-CT, the standardized uptake value (SUV) is a measure of fluorodeoxyglucose (FDG) uptake, which has been shown to be helpful in estab...

Objective: In this study, we aimed to explore prognostic importance of definition of preoperative metabolic tumor volume in esophageal cancer patients.Methods: 22 patients who have histologically proven stage IIA-III esophageal cancer and underwent 18F-FDG PET/CT for preoperative staging of disease were included to the study. After 18F-FDG PET/CT, all the patients underwent surgery within 4 weeks period. Patients have been followed up until death or Sept 15th, 2012. Dates of death were recorded for survival analysis. During evaluation of 18F-FDG PET/CT images, metabolic tumor volumes were calculated by drawing the isocontour region of interests from all visually positive FGD uptake lesions.Results: 22 patients (15M, 7F; mean age: 65.1±8.4, min-max:48-80) underwent 18F-FDG PET/CT for preoperative staging of esophageal cancer. Preoperative diagnosis was squamous cell and adeno cancer in 17 (%77) and 5 (%23) patients, respectively. Location of primary tumor is distal, proximal and mid-esophagus in 13 (%59), 6 (%27) and 3 (%13) patients, respectively. Primary tumor of all the patients were FDG avid (mean SUVmax: 18.85±7.0; range: 5.5-35.1). Additionally, 18F-FDG uptake was seen in mediastinal lymph nodes in 13 patients (5.45±8.15; range: 2.6-29.9). Mean metabolic tumor volumes of primary esophageal lesions were calculated as 8.77±8.46cm3 (range: 2.3-34.2). Mean MTV of lymph nodes was 2.44±1.01cm3 (range: 0.4-3.6). Mean total metabolic tumor volume was calculated as 9.99±8.58cm3 (range: 2.3-27.3). 10 patients died during 447±121 days follow-up period. Mean survival time was 11.9±1.5 months (95%CI: 8.99-14.74) for entire patient group. Total metabolic tumor volume had a significant effect on survival (p=0.045) according to Cox proportional hazards regression analysis. One unit increase in MTV caused 1.1 (95%CI:1.003-1.196) fold increase in hazard, at any time.Conclusion: Definition of preoperative metabolic tumor volume has a prognostic value in the prediction of postoperative survival times. Patients who have higher preoperative metabolic tumor volumes could be good candidates for more aggressive chemo-radiation therapy regiments.Conflict of interest:None declared.

In patients with stage I-II breast cancer, SLN could be successfully demonstrated with lymphoscintigraphy and SGP by the peritumoral injection of filtered Tc-99m sulfur colloid and Tc-99m MIBI.

18F-fluorocholine has recently emerged as a very sensitive agent for seeking parathyroid adenomas. We represent a case with esophageal diverticulum incidentally detected on 18F-fuorocholine PET/CT, which should be kept in mind as a reason of false positivity in primary hyperparathyroidism.

No abstract