Abstract: OBJECTIVE: To assess the diagnostic value of fluorine-18 fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) using standard uptake values (SUV) in the differential diagnoses of indeterminate pulmonary nodules. Specifically, we assessed the probability of malignancy for various SUV ranges, and compared the diagnostic efficacy of SUV with and without correction for partial volume effects on the basis of lesion size. METHODS: The FDG-PET scans performed on 158 patients with biopsy-proven pulmonary lesions seen on computed tomography (CT) scan were retrospectively reviewed. Histopathological confirmation was obtained to establish the diagnosis of the lesions. A region of interest (ROI) was drawn for each lesion, and FDG uptake was quantified (SUV(raw)). The SUV(raw) values were normalized for the "size" of the pulmonary lesions measured on CT (SUV(size)). Sensitivity and specificity of FDG-PET for pulmonary lesions <2 cm in diameter or >/=2 cm in diameter were determined at SUV cutoff values of 2.5. The areas under the receiver-operating characteristic (ROC) curve for SUV(raw) and SUV(size) regarding the presence of malignancy were compared for statistical differences. The frequency of malignant lesions for each range of SUVs was obtained to produce the probability of cancer (POC). RESULTS: The mean SUV(raw) was 3.17 +/- 2.76 and 9.18 +/- 6.72 for benign and malignant lesions, respectively. When a SUV(raw) value of 2.5 was used as a cutoff, sensitivity and specificity were 89% and 51%, respectively, for all lesion sizes. The sensitivity and specificity at a cutoff SUV(raw) of 2.5 for lesions less than 2 cm in diameter were 75% and 72%, respectively, and 92% and 41% for lesions 2 cm or greater, respectively. The sensitivity and specificity at a cutoff SUV(size) of 2.5 were 88% and 42%, respectively. The area under the ROC curves for SUV(raw) and SUV(size) was 0.816 and 0.743, respectively (P value 0.034). When the SUV(raw) was divided into three groups, the probability of malignancy was 26% when the SUV(raw) was <2, 57% for 2 </= SUV(raw) < 6, and 89% for SUV(raw) >/= 6. CONCLUSIONS: The FDG-PET is a reasonably accurate and useful tool for characterizing the nature of indeterminate pulmonary lesions, although the specificity was not as high as that reported in the literature, probably owing in part to our patient population and selection bias. Our data suggest that reporting the results of PET studies as a probability rather than as positive or negative for malignancy would be more useful for further management decision making. Correction of SUVs for tumor size did not improve accuracy.
Abstract: An ectopic superior parathyroid adenoma (SPA) descends inferoposteriorly and can migrate to the posterior mediastinum. It often appears on sestamibi planar parathyroid imaging as an inferior lesion, which can be misleading to inexperienced surgeons. Its correct identification before surgery will be of great help for correct surgical planning. We assessed the appearance of descended SPA on SPECT imaging. METHODS: Sestamibi SPECT imaging studies performed on 103 patients who had parathyroid adenomas with their origin and locations confirmed by surgery and histology were retrospectively reviewed. Abnormal foci seen on the SPECT images were grouped as to location relative to the thyroid gland as superior (S), middle (M), and inferior (I). The proximity between the focus and the thyroid on the sagittal SPECT images was graded from 0 to 2 with 2 being widely separated. RESULTS: Of the 103 SPECT studies, 89 were positive. Eleven of the 89 visualized foci were at the S level: all were SPA. Ten foci were at the M level, including 6 SPA and 4 inferior parathyroid adenomas (IPA). There were 68 foci at the I level; none (0%) of 56 in the I0 location, 2 (25%) of 8 foci in the I1 location, and all (100%) of 4 abnormal foci in the I2 location were descended SPAs. CONCLUSION: The more posteriorly located the abnormal focus, the higher the probability of descended SPA. Recognition of the characteristic appearance of descended SPA on SPECT imaging can have a significant impact on the surgical approach and prevent failed neck exploration.
Abstract: PURPOSE: Conversion of red marrow (RM) to fatty marrow in the skeleton of the lower extremities begins at the distal end, ie, feet, and progresses proximally with distal bone marrow (ie, tibia) being converted more rapidly than proximal bone marrow (ie, femur). However, in an individual long bone, conversion begins in the diaphysis and progresses both distally and proximally (more rapidly toward the distal side). In a normal adult's femur, RM is present in the proximal one third or less. Reconversion of fatty marrow to RM is reported to occur in the reverse order of conversion. We assessed the frequency of various patterns of RM in the adult femur on In-111 leukocyte scans for a better understanding of the bone marrow regeneration process in individual long bones. METHODS: The patterns of marrow activity in the femur shown on In-111 leukocyte scans performed in 354 adults were divided into a) RM limited to the proximal one third or less, b) to the proximal two thirds, c) to the proximal one third and distal one third with no activity in the middle shaft, and d) in the entire femur. RESULTS: There were 207 patients with pattern A, 91 pattern B, 14 pattern C, and 42 pattern D. CONCLUSIONS: A considerably higher number of adults showed pattern B than pattern C. This suggests that regeneration of diaphyseal marrow precedes that of the distal marrow in an individual long bone or possibly that conversion of the latter precedes the former, which is different from that proposed in the literature.
Abstract: Current trends in patient care include the desire for minimizing invasiveness of procedures and interventions. This aim is reflected in the increasing utilization of sentinel lymph node biopsy, which results in a lower level of morbidity in breast cancer staging, in comparison to extensive conventional axillary dissection. Optimized lymphoscintigraphy with triangulated body marking is a clinical option that can further reduce morbidity, more than when a hand held gamma probe alone is utilized. Unfortunately it is often either overlooked or not fully understood, and thus not utilized. This results in the unnecessary loss of an opportunity to further reduce morbidity. Optimized lymphoscintigraphy and triangulated body marking provides a detailed 3 dimensional map of the number and location of the sentinel nodes, available before the first incision is made. The number, location, relevance based on time/sequence of appearance of the nodes, all can influence 1) where the incision is made, 2) how extensive the dissection is, and 3) how many nodes are removed. In addition, complex patterns can arise from injections. These include prominent lymphatic channels, pseudo-sentinel nodes, echelon and reverse echelon nodes and even contamination, which are much more difficult to access with the probe only. With the detailed information provided by optimized lymphoscintigraphy and triangulated body marking, the surgeon can approach the axilla in a more enlightened fashion, in contrast to when the less informed probe only method is used. This allows for better planning, resulting in the best cosmetic effect and less trauma to the tissues, further reducing morbidity while maintaining adequate sampling of the sentinel node(s).
Abstract: BACKGROUND: There are no studies that have directly investigated the incremental reduction in sensory morbidity that lymphoscintigraphy images (LS) and triangulated body marking or other skin marking techniques provide during sentinel lymph node biopsy (SLNB) compared to using only the probe without LS and skin marking or using only dye. However, an indirect assessment of this potential for additional sensory morbidity reduction is possible by extracting morbidity data from studies comparing the morbidity of SLNB to that of axillary lymph node dissection. METHODS: A literature search yielded 13 articles that had data on sensory morbidity at specific time points on pain, numbness or paresthesia from SLNB that used radiotracer and probe or used only dye as a primary method of finding the sentinel node (SN). Of these, 10 utilized LS, while 3 did not utilize LS. By matching the data in studies not employing LS to the studies that did, comparisons regarding the percentage of patients experiencing pain, numbness/paresthesia after SLNB could be reasonably attempted at a cutoff of 9 months. RESULTS: In the 7 studies reporting on pain after 9 months (> 9 months) that used LS (1347 patients), 13.8% of patients reported these symptoms, while in the one study that did not use LS (143 patients), 28.7% of patients reported these symptoms at > 9 months (P < 0.0001). In the 6 studies reporting on numbness and/or paresthesia at > 9 months that used LS (601 patients), 12.5% of patients reported these symptoms, while in the 3 studies that did not use LS (229 patients), 23.1% of patients reported these symptoms at > 9 months (P = 0.0002). Similar trends were also noted for all these symptoms at < or = 9 months. CONCLUSION: Because of variations in techniques and time of assessing morbidity, direct comparisons between studies are difficult. Nevertheless at a minimum, a clear trend is present: having the LS images and skin markings to assist during SLNB appears to yield more favorable morbidity outcomes for the patients compared to performing SLNB with only the probe or performing SLNB with dye alone. These results are extremely pertinent, as the main reason for performing SLNB itself in the first place is to achieve reduced morbidity.
Abstract: OBJECTIVES: Abnormal bone scan findings in the spine are often nonspecific. The confidence level for the differential diagnosis between metastases and benign or degenerative changes may vary depending on their appearance, location or intensity. The recognition of a specific pattern for certain benign conditions and its subcategorization will increase the credibility of bone scan interpretation while retaining a high level of sensitivity. We report one such finding, focally increased activity on the lateral side of the cervical spine on the posterior view, most common at the C3-C5 level ("mid-cervical-lateral-focus"). METHODS: Of 481 patients with various cancers who had at least 2 whole-body bone scans, 6 months or more apart, 41 patients were judged to show this characteristic "mid-cervical-lateral-focus" on at least one scan. Final diagnosis (metastasis vs. benign) for each "mid-cervical-lateral-focus" was made based on clinical grounds and serial bone scans. RESULTS: The bone scan showed definite multiple metastases in 15 patients, and the differential diagnosis for the "mid-cervical-lateral-focus" was already clinically irrelevant in these patients. Nevertheless, the "mid-cervical-lateral-focus" was finally judged to be benign in 14 of these 15 patients and in all remaining 26 patients without other obvious metastases. The only "mid-cervical-lateral-focus" judged to be a metastatic focus was not only clinically redundant, but also the most intense among all the "mid-cervical-lateral-foci." in this series (too intense to be interpreted as benign). CONCLUSION: The typical "mid-cervical-lateral-focus" pattern is extremely unlikely to represent metastases (virtually 0% in patients without other obvious metastases). This knowledge helps exclude metastases on bone scans.
