Faculty Bibliography

OBJECTIVE: A considerable change of urinary bladder (UB) shape in PET compared with CT in integrated PET/CT system is frequently noted. This study initially evaluated this finding with and without oral contrast (OC) use. In addition, a one bed pelvic section (PLV) repeat acquisition was investigated as a solution to this problem. METHODS: (18)FDG PET/CTs of 88 patients were analyzed. OC was administered in 68 patients, of whom 31 had PLV images taken 5-10 min later. Three-dimensional mid-UB CT and PET matching measurements were compared. In addition, UB walls displacement between CT and PET were analyzed. RESULTS: The mean UB height was significantly increased (P < 0.001) in PET when compared with CT, both anteriorly and posteriorly; however, UB width and depth were not significantly different. An upward shift of superior UB wall in PET from equivalent CT images was noted, whereas there was no appreciable displacement of the other UB walls. The percent UB height increase on PET from CT was significantly greater with than without OC use. The UB height difference between PET and CT was markedly reduced on PLV when compared with the original scans. CONCLUSIONS: Caution should be exerted during the interpretation of PET/CT scans of the pelvis as there is significant upward expansion of UB on PET compared with CT that appears to be exaggerated by OC use, likely due to additional fluid load. The PET/CT fusion errors of UB can be substantially resolved through a separate PLV acquisition presumably due to the shorter time interval of UB scan completion between CT and PET

PURPOSE: Study impact of F-18 FDG PET/CT on initial staging, restaging, and evaluating treatment response (ETR) in bone and soft tissue sarcomas (BSTS), focusing on discrepancy between CT and PET portions. PATIENTS AND METHODS: Ninety-three BSTS patients having 204 F-18 FDG PET/CT studies were retrospectively reviewed. They were divided into 4 groups. Group I for initial staging included 16 patient studies. The other 3 groups were divided according to the time interval from last treatment received. Group II for ETR up to 2 months included 83 studies. Group III was for early restaging after 2 to 6 months included 45 studies. Group IV was for long-term follow-up after 6 months included 60 studies. All results were confirmed either by pathology, or by clinical follow-up. RESULTS: Sixteen studies for initial staging were concordant in 14 and discordant in 2 patients (48 lesions, 46 concordant, and 2 discordant). PET showed 97.2% sensitivity and 100% specificity versus 100% and 91.6% on CT. Regarding the other 3 groups, 498 lesions were detected; PET and CT were concordant in 436/498 (88%) and discordant in 62/498 (12%). In group II for ETR, PET and CT were concordant in 64/83 (77%) and discordant in 19/83(23%) studies-13 showed excellent to complete response on PET with partial response (PR) or stable disease (SD) on CT; 6 studies in PET showed PR versus SD or progression of disease (PD) on CT. In group III, for early restaging of disease 36/45 (80%) concordant and 9/45 (20%) discordant (3 showed excellent to complete response and 2 PR on PET versus CT SD, 3 PET PR versus CT PD, and 1 PET study showed PD while CT showed SD). In group IV, for long-term restaging, 49/60 (82%) were concordant and 11/60 (18%) were discordant; 9 PET studies were negative for active disease versus CT positive and 2 PET studies showed PD, CT was negative. PET alone showed 94.1% sensitivity and 94.6% specificity versus 97.2% and 63.5% for CT, 100% and 95.9% for PET/CT. CONCLUSIONS: In BSTS for the purpose of initial staging, ETR, short-term, or long-term restaging, FDG-PET is more accurate than CT. Combined PET/CT has higher accuracy than either alone

Primary malignant tumors of the spine account for less than 5% of primary bone tumors. Data from the SEER program suggest that the most common bone sarcomas are osteosarcoma, chondrosarcoma, Ewing's sarcoma, chordoma, and malignant fibrous histiocytoma/fibrosarcoma. During the last two decades, tremendous progress has been made in clinical aspects, surgical approaches, and reconstruction with instrumentation at all levels of the spine. Stabilization procedures, including vertebroplasty and kyphoplasty, have further allowed palliation of pain and symptom relief from compression fractures. Improved radiation techniques have offered the potential for improved local control. This article reviews the changes in surgical philosophy in the management of malignant spinal tumors during the past two decades

OBJECTIVE: To determine if chemotherapy offers a survival benefit to patients with large, high-grade, primary extremity liposarcoma. SUMMARY BACKGROUND DATA: The impact of chemotherapy on the survival of patients with primary extremity soft tissue sarcoma is controversial and its effect on individual histologic subtypes is not defined. PATIENT AND METHODS: Two prospectively collected sarcoma databases were used to identify all patients with >5 cm, high-grade, primary extremity liposarcoma that underwent surgical treatment of cure from 1975 to 2003 (n = 245). Clinical, pathologic and treatment variables were analyzed for disease-specific survival (DSS), distant recurrence-free survival (DRFS) and local recurrence-free survival (LRFS). RESULTS: Sixty-three (26%) patients were treated with ifosfamide based chemotherapy (IF), 83 (34%) with doxorubicin based chemotherapy (DOX) and 99 (40%) received no chemotherapy (NoC). To assess the impact of DOX, a contemporary cohort analysis of patients treated from 1975 to 1990 was performed. The 5 year DSS of the DOX treated patients was 64% (53%-74%) compared with 56% (51%-79%) for the NoC patients (log-rank P value = 0.28). To assess the impact of IF, a contemporary cohort analysis of patients treated from 1990 to 2003 was performed. The 5 year DSS of the IF treated patients was 92% (84%-100%) compared with 65% (51%-79%) for the NoC patients (log-rank P value = 0.0003). Independent prognostic factors for improved DSS were smaller size (HR = 0.7, P = 0.01), myxoid/round cell histologic subtype (HR = 0.3, P = 0.03) and treatment with IF (HR = 0.3, P = 0.01). The five-year DRFS of the IF treated patients was 81% (70%-92%) compared with 63% (50%-76%) for the NoC patients (log-rank P value = 0.02). The 5 year LRFS of the IF treated patients was 86% (76%-96%) compared with 87% (77%-97%) for the NoC patients (log-rank P value = 0.99). CONCLUSIONS: In patients with large, high-grade, primary extremity liposarcoma; DOX is not associated with improved DSS and IF is associated with an improved DSS. Treatment with IF should be considered in patients with high-risk primary extremity liposarcoma