OBJECTIVE: To evaluate the potential influence of transaxillary augmentation mammoplasty on future detection of sentinel lymph node. MATERIALS AND METHODS: Prospective controlled study where 22 patients were selected and divided into two groups (post-mammoplasty and control) corresponding to 43 breasts (22 in the post-mammoplasty group and 21 in the control group) evaluated by lymphoscintigraphy immediately after periareolar 99mTc-phytate injections. In the statistical analysis, p values < 0.05 were considered as significant. RESULTS: All the breasts in the post-mammoplasty group presented lymphatic drainage to the axillary chain, with no difference as compared with the control group (p = 0.488). The average number of hot lymph nodes was 1.27 ± 0.46 in the post-mammoplasty group, and 1.33 ± 0.58 in the control group (p = 0.895). The mean time required to visualize the first lymph node was 3.14 ± 4.42 minutes in the post-mammoplasty group, and 5.48 ± 5.06 minutes in the control group (p = 0.136). CONCLUSION: Transaxillary augmentation mammoplasty did not affect the future detection of sentinel lymph node.

Keywords: Sentinel lymph node biopsy, Mammoplasty, Scintigraphy, Breast implants, Breast neoplasms

OBJECTIVE: To evaluate the prevalence of exclusive lower extremity metastases, specifically in the femur and below the knee, observed at ¹⁸F-NaF PET/CT. MATERIALS AND METHODS: One thousand consecutive PET/CT studies were retrospectively evaluated for the presence of exclusive uptake in lower extremities suggesting metastatic involvement. The presumptive diagnoses based on such uptakes were subsequently obtained by evaluation of other imaging studies. RESULTS: No exclusive uptake suggestive of metastasis below the femur was observed in the present series. Exclusive uptake was observed in the proximal femur with a presumptive diagnosis of metastasis in two patients. CONCLUSION: The prevalence of exclusive metastasis below the femur is low and scanning from head to knees is appropriate in most cases.

Keywords: PET/CT; ¹⁸F-NaF; Scintigraphy; Bone; Metastasis.

OBJECTIVE: To assess the cutoff values established by ROC curves to classify ¹⁸F-NaF uptake as normal or malignant. MATERIALS AND METHODS: PET/CT images were acquired 1 hour after administration of 185 MBq of ¹⁸F-NaF. Volumes of interest (VOIs) were drawn on three regions of the skeleton as follows: proximal right humerus diaphysis (HD), proximal right femoral diaphysis (FD) and first vertebral body (VB1), in a total of 254 patients, totalling 762 VOIs. The uptake in the VOIs was classified as normal or malignant on the basis of the radiopharmaceutical distribution pattern and of the CT images. A total of 675 volumes were classified as normal and 52 were classified as malignant. Thirty-five VOIs classified as indeterminate or nonmalignant lesions were excluded from analysis. The standardized uptake value (SUV) measured on the VOIs were plotted on an ROC curve for each one of the three regions. The area under the ROC (AUC) as well as the best cutoff SUVs to classify the VOIs were calculated. The best cutoff values were established as the ones with higher result of the sum of sensitivity and specificity. RESULTS: The AUCs were 0.933, 0.889 and 0.975 for UD, FD and VB1, respectively. The best SUV cutoffs were 9.0 (sensitivity: 73%; specificity: 99%), 8.4 (sensitivity: 79%; specificity: 94%) and 21.0 (sensitivity: 93%; specificity: 95%) for UD, FD and VB1, respectively. CONCLUSION: The best cutoff value varies according to bone region of analysis and it is not possible to establish one value for the whole body.

Keywords: ¹⁸F-NaF PET/CT; ROC curve; Cutoff values; Normal uptake; Malignant uptake