Assessment of Bone Metastasis using Nuclear Medicine Imaging in Breast Cancer: Comparison between PET/CT and Bone Scan / 핵의학분자영상

PURPOSE: Bone metastasis in breast cancer patients are usually assessed by conventional Tc-99m methylene diphosphonate whole-body bone scan, which has a high sensitivity but a poor specificity. However, positron emission tomography with 18F-2-deoxyglucose (FDG-PET) can offer superior spatial resolution and improved specificity. FDG-PET/CT can offer more information to assess bone metastasis than PET alone, by giving a anatomical information of non-enhanced CT image. We attempted to evaluate the usefulness of FDG-PET/CT for detecting bone metastasis in breast cancer and to compare FDG-PET/CT results with bone scan findings. MATERIALS AND METHODS: The study group comprised 157 women patients (range: 28~78 years old, mean+/-SD=49.5+/-8.5) with biopsy-proven breast cancer who underwent bone scan and FDG-PET/CT within 1 week interval. The final diagnosis of bone metastasis was established by histopathological findings, radiological correlation, or clinical follow-up. Bone scan was acquired over 4 hours after administration of 740 MBq Tc-99m MDP. Bone scan image was interpreted as normal, low, intermediate or high probability for osseous metastasis. FDG PET/CT was performed after 6 hours fasting. 370 MBq F-18 FDG was administered intravenously 1 hour before imaging. PET data was obtained by 3D mode and CT data, used as transmission correction database, was acquired during shallow respiration. PET images were evaluated by visual interpretation, and quantification of FDG accumulation in bone lesion was performed by maximal SUV(SUVmax) and relative SUV(SUVrel). RESULTS: Six patients(4.4%) showed metastatic bone lesions. Four(66.6%) of 6 patients with osseous metastasis was detected by bone scan and all 6 patients(100%) were detected by PET/CT. A total of 135 bone lesions found on either FDG-PET or bone scan were consist of 108 osseous metastatic lesion and 27 benign bone lesions. Osseous metastatic lesion had higher SUVmax and SUVrel compared to benign bone lesion(4.79+/-3.32 vs 1.45+/-0.44, p=0.000, 3.08+/-2.85 vs 0.30+/-0.43, p=0.000). Among 108 osseous metastatic lesions, 76 lesions showed as abnormal uptake on bone scan, and 76 lesions also showed as increased FDG uptake on PET/CT scan. There was good agreement between FDG uptake and abnormal bone scan finding (Kendall tau-b: 0.689, p=0.000). Lesion showed increased bone tracer uptake had higher SUVmax and SUVrel compared to lesion showed no abnormal bone scan finding (6.03+/-3.12 vs 1.09+/-1.49, p=0.000, 4.76+/-3.31 vs 1.29+/-0.92, p=0.000). The order of frequency of osseous metastatic site was vertebra, pelvis, rib, skull, sternum, scapula, femur, clavicle, and humerus. Metastatic lesion on skull had highest SUVmax and metastatic lesion on rib had highest SUVrel. Osteosclerotic metastatic lesion had lowest SUVmax and SUVrel. CONCLUSION: These results suggest that FDG-PET/CT is more sensitive to detect breast cancer patients with osseous metastasis. CT scan must be reviewed cautiously skeleton with bone window, because osteosclerotic metastatic lesion did not showed abnormal FDG accumulation frequently.

Assessment of Perirenal Fat Infiltration in Renal Cell Carcinoma by CT / 영남의대학술지

Forty-two preoperative CT scans with renal cell carcinoma were reviewed and compared with pathologic findings to evaluate the differential points between stage I and II. Regardless of whole body staging, perirenal fat infiltrations were seen in 9 cases and the other 33 cases showed no infiltration onto perirenal fat tissue. We retrospectively reviewed them by comparing tumor size and CT findings, following three view points, lobulating contour of tumor margin, thickening of Gerota's fascia and strands in perirenal fat tissue. The size of them was 2-15 cm, size of the stage I tumors was 2-15 cm and that of stage II was 6-15 cm. In stage I(n=33), 25 cases(76%) showed smooth margin, and the others(n=8) showed lobulating contours. Thickening of Gerota's fascia was observed in 7 cases(21%) and strands in perirenal fat tissue in 14(42%). Of these, only one positive finding was seen in 7 cases(21%), 2 findings in 6(18%), 3 findings in 3(9%) and nothing in 17cases(51%). In stage II(n=9), 3 cases(34%) showed smooth margin, and the others(n=6) showed lobulating contours. Thickening of Gerota's fascia were observed in 5 cases(55%) and strands in perirenal fat tissue in 9(100%). Of these, one finding was seen in 2 cases(22%), 2 findings in 3(33%), 3 findings in 4(44%). In conclusion, it is insufficient to evaluate the perirenal fat infiltration in renal cell carcinoma with only one positive finding of 3 view points; lobulation of tumor margin, thickening of Gerota's fascia, strands in perirenal fat tissue. But if all these findings are shown, it is helpful to determinate perirenal fat infiltration of renal cell carcinoma.

Dynamic CT Findings of Eosinophilic Hepatic Abscess and Its Clinical Course

PURPOSE: To evaluate dynamic CT features and its clinical courses of eosinophilic hepatic abscess. MATERIALS AND METHODS: Two-phase dynamic CT findings and the clinical courses of 13 pathologically proven cases of eosinophilic abscess were reviewed. All patients showed peripheral eosinophilia, and diagnoses were confirmed by ultrasound-guided biopsy(n=9) or operation(n=4). In two of the four patients who underwent segmental hepatectomy, worms of the species Fasciola hepatica were detected. Follow-up CT scans after treatment with antibiotics or praziquantel were available in seven and eight patients, respectively. RESULT: All hepatic lesions were found ina subcapsular location or in contact with Glisson's capsule around the bile duct. Arterial-dominant phase CT(n=11)demonstrated clusters of ill-defined low density masses without rim enhancement. Late-phase CT(n=13) more clearly depicted clustering lesions with enhancing rims and diminution of the low-density area. Follow-up CT scans aftertreatment with antibiotics(n=7) showed no change in the lesions in three patients and slight shrinkage of the mainmass with additional new lesions in four. On CT scans of nine patients performad after praziquantel therapy, hepatic masses were seen in all patients to be very slightly smaller after improvement of peripheral hypereosinophilia. CONCLUSION: Two-phase dynamic CT features appear to be helpful for the diagnosis ofeosinophilic hepatic abscess in patients with peripheral eosinophilia. Parasitic infestation by Fasciola hepaticafor example, is the presumed cause of such abscesses, though further studies are required.

CT findings of Desmoid tumor arising at Abdominai Wall / 영남의대학술지

Desmoid tumor is a type of fibromatosis usually arise in deep musculo-aponeurotic structures, primarily of the trunk and extremities. It is characterized by proliferation of fibroblastic tissue and does not metastasize but may be locally aggressive. Eventhough the surgical margin reveals clean, recurrence often occurs. To analyze the extent of the tumor and homodynamic characteristics exactly, we performed IV bolus CT. Desmoid tumors show peripheral rim enhancement on early phase scan and more strong, central enhancement on late phase IV bolus CT, which reflects abundant fibroblastic components of the tumor. We report two cases of pathologically confirmed desmoid tumor performed IV bolus CT.