A 37-year-old man with multiple myeloma in remission underwent routine fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) study for disease restaging. Both FDG-PET and CT images showed focal abnormalities in the region of the T6 vertebra, but the fused images that are routinely provided with PET/CT could precisely localize the FDG active lesion to a soft tissue focus in the epidural space, away from a lytic nonactive vertebral body lesion despite their close proximity. The PET/CT scan identified a few other metabolically active osseous lesions out of many lytic bony changes throughout the skeleton. Accordingly, the patient received the correct management for an impending spinal cord compression at the appropriate time, in addition to systemic therapy for disease relapse.

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: To evaluate the impact of F-18 fluorodeoxyglucose (FDG) positron emission tomography with fused computerized tomography (PET/CT) in comparison with same day contrast enhanced CT (CE-CT) in breast cancer management. Method: Seventy studies in 49 breast cancer patients, 17 for initial and 53 for restaging disease were included. All patients underwent PET/CT for diagnostic purposes followed by CE-CT scans of selected body regions. PET/CT was started approximately 90 minutes following IV injection of 10–15 mCi of F-18 FDG on a GE Discovery PET/CT system. Oral contrast was given before F-18 FDG injection. The CE-CT was performed according to departmental protocol. Results: Out of a total of 257 lesions, 210 were concordant between PET/CT and CE-CT. There were 47 discordant lesions, which were verified by either biopsy (35) or follow-up (12 PET positive CE-CT negative lesions). PET/CT correctly identified 25 true positive (TP). CE-CT identified 2 TP lesions missed by PET/CT which were false negatives (FNs): one liver metastasis with necrosis, which was nonavid to FDG uptake because of necrosis and a second one missed on abdominal metastatic node, which did not change staging or treatment. PET/CT incorrectly identified 2 false positive lesions while CE-CT incorrectly identified 18 false positive. TP recurrence of the disease was found by PET/CT in 44% (15/34 pts), whereas 56% (19/34 pts) were free of disease. The CE-CT described progression of the disease in 1 true negative PET/CT study and no progression in 2 TP PET/CT studies. The sensitivity, specificity, accuracy, positive productive value, and negative productive value for PET/CT were 97.8%, 93.5%, 97.3%, 99.1%, 85% and for CE-CT were 87.6%, 42%, 82.1%, 91.6%, 31.7%. Conclusion: In this study, PET/CT played a more important role than CE-CT scans alone and provided an impact on the management of breast cancer patients.

Distant extrapelvic metastases appear in approximately in 10% of the patients with squamous cell anal cancer (SCAC) and survival depends on the treatment strategy. Exact staging leads to optimal planning of multimodality therapy and the adequate evaluation of treatment response can improve the prognosis of the disease. Diagnosis and staging of SCAC are commonly performed using contrast-enhanced computerized tomography(CT) and interpretation of the findings for tumor biological behavior. F18-fluoro-2 deoxy-D glucose positron emission tomography((18)F-FDG PET) reveals aspects of tumor function and allows metabolic measurements. Combined PET/CT scans permit exact localization with anatomical criteria of the hypermetabolic (18)F-FDG avid malignant lesions. We present a patient with SCAC in whom, according to PET/CT findings, the initial stage was changed from II (T2N0M0) to III A (T2N2M0). Radiation therapy (RT) and chemotherapy achieved a good therapeutic response but early follow up revealed new paraaortic lymph node (LN) metastases, as well as an uncommon left supraclavicular LN metastasis from the same primary carcinoma. The disease was restaged as stage IV (T2N2M1) and radiation therapy was substituted by chemotherapy.

673 Objectives: Upward expansion of the urinary bladder (UB) in PET compared with CT images in the integrated PET/CT system due to continuous UB filling frequently results in considerable image fusion errors, particularly when oral contrast is used. A repeat pelvic section acquisition is investigated in this study as a practical solution to this problem. Methods: Whole body F-18 FDG scans of 31 consecutive patients (12 men, 19 women, mean age 60 ± 14 years) with known or suspected malignancy were analyzed. Scans were obtained using a dedicated PET/CT scanner (GE Discovery ST) with approximately 1litre oral contrast (1.5% water diluted Gastrographin®) given to 27 of the patients. All patient underwent a repeat 5-minutes pelvic section scan. Patients were asked to empty their UB prior to both scans. Three-dimension mid-UB CT and PET matching measurements in millimeter (mm) were obtained from the fused images, in addition to assessment of the anterior and posterior vertical dimensions change and UB walls displacement between CT and PET images. Results: The mean UB height was significantly increased (p Conclusions: The UB image fusion errors in PET/CT scans can be substantially resolved by a separate acquisition of a pelvis section presumably due to shorter time interval of UB scan completion between CT and PET. This repeat short scan should be considered for better localization of pelvic PET findings, particularly if FDG lesion is suspected above the UB.

Sentinel node imaging and biopsy have become standard procedures for staging early breast cancer. Positive sentinel lymph node (SLN) biopsy necessitates the need for axillary lymph node dissection (ALND). Failure to visualize a sentinel lymph node in recurrent breast cancer after treatment by surgery, chemotherapy, and high-dose postoperative radiation therapy is almost the case in every patient. The reason for failure to visualize the sentinel node is the fibrosis that follows high-dose radiotherapy and blocks the lymphatics preventing spread of the tumor cells to the lymph nodes. Alternative pathways for the drainage of lymph from the breast are developed in these patients. We have previously reported on the alternative pathways of lymphatics to the contralateral axilla, supraclavicular area, and also reported on the development of intramammary lymph nodes. In this report, we are presenting another alternative pathway of lymphatics to the region of the epigastrium below the lower end of the sternum.