18F-FDG retention index and biologic prognostic parameters in breast cancer.

AIM: To analyze the correlation between [(18)F]-fluoro-2-deoxy-D-glucose (F-FDG) uptake assessed by positron emission tomography/computed tomography (PET/CT) in breast tumors and histopathologic and immunohistochemical prognostic factors. MATERIAL AND METHODS: Sixty-eight women with breast cancer were prospectively evaluated. PET/CT was requested in the initial staging previous to neoadjuvant chemotherapy (multicentric study).All the patients underwent a standard (18)F-FDG PET/CT followed by a delayed acquisition, 1 hour (PET-1) and 3 hours (PET-2) after FDG administration. Both examinations were evaluated qualitatively and semiquantitatively (SUV(max) values) in PET-1 (SUV-1) and in PET-2 (SUV-2). The percentage variation of the standard uptake values (retention index) between PET-1 and PET-2 was calculated.Clinical and metabolic stages were assessed according to TNM classification. All biologic prognostic parameters, such as the receptor status, p53 and c-erbB-2 expression, proliferation rate (Ki-67), and grading were determined from tissue of the primary tumor. Metabolic, clinical, and biologic parameters were correlated. RESULTS: A positive relationship was found between the SUV(max), tumor size, clinical, and metabolic stages. SUV-1 and SUV-2 values showed significant statistical correlation (P < 0.05) with PET stage and tumor size assessed by PET. On the contrary, the retention index showed relation with clinical stage (P < 0.05).When related to the biologic parameters, retention index showed the best results, with positive and significant relation (P < 0.05), with histologic grade, and Ki-67 and c-erbB-2 expression. Isolated SUV values only showed significant relation to Ki-67 expression. CONCLUSION: The retention index showed the best relation with biologic and clinical parameters compared with isolated SUVmax values for what could be a predictive marker of tumor biologic behavior.

Value of 4-dimensional 18F-FDG PET/CT in the classification of pulmonary lesions.

UNLABELLED: Our aim was to evaluate the effect of 4-dimensional (4D) (18)F-FDG PET/CT in the detection of pulmonary lesions. METHODS: Fifty-seven pulmonary lesions were prospectively assessed in 37 patients (26 men and 11 women) with a mean age of 66.3 y. Twenty-nine of these patients had a history of neoplasm. All patients underwent 3-dimensional (3D) total-body PET/CT and 4D thoracic PET/CT (synchronized with respiratory movement). Maximum standardized uptake value (SUVmax) was obtained for each lesion in both studies. For the 4D studies, we selected the SUVmax in the respiratory period with the highest uptake ("best bin") and the average value over all bins ("average gated"). SUVmax percentage difference between 3D and 4D PET/CT and the relationship of this value to the diameter and location of the lesions were calculated. Statistical parameters were calculated for 3D and 4D PET/CT. RESULTS: Fifty-four of 57 lesions showed an increase of SUVmax in the 4D study with respect to the 3D study. The mean SUVmax was 3.1 in the 3D study. 4D PET/CT studies showed a mean SUVmax of 4.5 for the best-bin study and 3.9 for the average gated study. The percentage difference in mean SUVmax between 3D and 4D studies (best bin and averaged gated) was 72.9% and 48.8%, respectively. The smaller the lesion, the greater was the SUVmax percentage difference (P < 0.05). However, no statistical differences dependent on the location of the lesions were observed. Final diagnosis showed that 37 lesions were malignant. The sensitivity, specificity, positive predictive value, and negative predictive value were 37.8%, 95%, 93%, and 45%, respectively, for 3D studies and 70.3%, 70%, 81.2%, and 56%, respectively, for 4D best-bin studies. CONCLUSION: Characterization of malignant lung lesions was better with 4D PET/CT than with standard PET/CT.

Impact of 18F-FDG PET/CT with retrograde filling of the urinary bladder in patients with suspected pelvic malignancies.

UNLABELLED: The purpose of this study was to assess the feasibility of selective pelvic PET/CT with retrograde bladder irrigation in evaluating pelvic pathologies. METHODS: Thirty-eight patients (22 women and 16 men), with a mean age of 61 y (range, 41-81 y) and a neoplastic background (most of them of pelvic pathology), were assessed with PET/CT. The most prevalent findings were urothelial (14 cases), gynecologic (12 cases), and rectal (7 cases) cancers. All but 3 patients had undergone previous surgical procedures or radio- or chemotherapy. Twenty-two patients had suspected pelvic pathology on a previous diagnostic CT scan. All the patients underwent a standard PET/CT protocol (from head to upper thighs) 60 min after the intravenous injection of 370 MBq of (18)F-FDG. Additional delayed pelvic PET/CT images were acquired with a filled-bladder technique. Both series of images were assessed by 2 experienced observers. A lesion was classified as malignant if it showed a standardized uptake value greater than 2.5 or, in the case of subcentimetric lesions, any uptake greater than background activity that persisted or increased on delayed pelvic imaging. All lesions were evaluated histologically or by clinical follow-up. RESULTS: Twenty-seven of 43 studies were categorized as pathologic using PET/CT. Nineteen studies showed abnormalities in the pelvis; the findings of 5 of these studies were false-positive. Ten studies showed pathologic (18)F-FDG uptake in the bladder wall; in 7 of these studies the uptake was found to be true-positive on histopathologic examination. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT in the pelvic assessment were 100%, 83%, 74%, 100%, and 76%, respectively. The retrograde filling reduced the interference with physiologic urinary accumulation of (18)F-FDG in patients with possible pelvic lesions; no false-negative results were documented. CONCLUSION: In (18)F-FDG PET studies, retrograde filling of the urinary bladder is recommended to assess bladder wall lesions and malignancies in other pelvic locations.

Changes in regional cerebral blood flow after body image exposure in eating disorders.

Relationships of 'perceptual distortion' and 'cognitive evaluation' components of body image disturbances to brain activity were investigated. Changes in regional cerebral blood (rCBF) of nine patients with anorexia nervosa restrictive type (AN), 13 patients with bulimia nervosa purging type (BN) and 12 controls following three experiments with single photon emission computed tomography (SPECT) were compared: at rest, following a landscape video presentation (neutral stimulus), and after their filmed body image (positive stimulus) exposure. Body distortion was measured with the Silhouette test and body dissatisfaction with the Body Shape Questionnaire (BSQ). Patients with AN showed a hyperactivation of the left parietal and right superior frontal from neutral to positive stimulus. Patients with BN showed a hyperactivation of the right temporal and right occipital areas. Changes in BSQ responses were associated with changes in the right inferior frontal and right temporal rCBF, whereas changes in body distortion were related to the left parietal. The activation of the right temporal after the own body image exposure might be in accordance with the aversive events' response. Functional abnormalities in AN might be related to the storage of a distorted prototypical image of the body in the left parietal lobe.

Scintigraphic diagnosis of infectious complications in renal failure patients undergoing hemodialysis, continuous ambulatory peritoneal dialysis or renal transplant

Patients with end-stage renal disease have two therapeutic options, dialysis and renal transplantation. Infectious complications occurring in such patients will not only condition the effectiveness of such treatments, but are among the main causes of morbidity and mortality in such cases. Knowledge of the advantages and limitations of nuclear techniques is essential for management of these conditions.

Pacientes em estágio final de doença renal têm duas opções terapêuticas, diálise e transplante renal. Complicações infecciosas que ocorrem em cada paciente são as principais causas de morbidade e mortalidade nestes casos. Conhecimentos das vantagens e limitações de técnicas nucleares são essenciais para o acompanhamento nestas condições.