PURPOSE: To evaluate the usefulness of a new model of the stent graft, and of tissue response related to placement of the stent graft. MATERIALS AND METHODS: The stent graft was constructed from polyurethane (Pellethane) graft and Hanaro stent (12 mm in diameter, 45 mm in length, 10 bends). A stent grafts was inserted into the lower thoracic aorta in each of six adult mongrel dogs (body weight, 12-16 kg). At one, two, four, and six months, follow-up studies of angiography and spiral CT angiography were performed to evaluate vascular patency, vascular stenosis, and thrombus formation. Two dogs were sacrificed at 1 month, 2 months, and 6 months after insertion of the stent graft and macroscopic, light microscopic, and scanning electron microscopic examinations of the aortic segment including the stent graft were performed to evaluate intimal hyperplasia, endothelial growth to the graft, and thrombus formation. RESULTS: During follow-up at one, two, four, and six months, angiography or spiral CT angiography showed 20-100% luminal stenosis or occlusion of the lower thoracic aorta by the thrombus and perigraft leaks in three dogs (50%), and collateral vessels caused by occlusion of the aorta in two (33.3%). On gross examination, there were thrombi of 1-5 mm thickness at the graft portions in all dogs, and this thickness gradually increased. The mean thickness of intimal hyperplasia at the stent portion gradually increased from 120um to 227um and the mean thickness of intimal hyperplasia at the graft portion from 93um to 914um. This thickness was greater at the graft portion than at the stent portion. Scanning electron microscopy showed elliptical endothelial lining on the neointimal surfaces at each end of the graft. CONCLUSION: Thrombi caused stenosis or occlusion of the stent graft. In order for such a graft to be ideal, further study is needed.
Adult ; Angiography ; Animals ; Aorta ; Aorta, Thoracic ; Blood Vessel Prosthesis* ; Constriction, Pathologic ; Dogs ; Endoleak ; Follow-Up Studies ; Humans ; Hyperplasia ; Microscopy, Electron, Scanning ; Phenobarbital ; Polyurethanes* ; Stents* ; Thrombosis ; Tomography, Spiral Computed ; Transplants ; Vascular Patency

PURPOSE: The purpose of this study was to determine whether magnetic resonance imaging (MRI) could assess the size of ductal carcinoma in situ (DCIS) more accurately compared to mammography and ultrasonography using the histopathological dimension of the surgical specimen as the reference measurement. METHODS: This was a retrospective review study using data from our institution database of breast cancer. Preoperative contrast-enhanced MRI, mammography and ultrasonography were performed to detect and assess the size of DCIS in 131 patients. The greatest dimensions of DCIS determined by the imaging modalities were compared with the histopathological dimensions of the surgical specimens. Intraclass coefficients were calculated to examine the agreement among the MRI, mammography and ultrasonography measurements. The Wilcoxon signed-rank test was used to evaluate the statistical significance of the differences in size among MRI, mammography or ultrasonography and histopathology findings. RESULTS: Of the 131 DCIS lesions, 126 (96.2%) were detected by MRI, 103 (78.6%) were detected by mammography, and 121 (92.4%) were detected by ultrasonography. The mean lesion size was 38.8 mm on histopathology, 36.0 mm on MRI, 28.8 mm on mammography, and 23.3 mm on ultrasonography, and there were no significant differences between sizes determined by histopathology and MRI, while there were significant differences between histopathology and the other modalities. The correlation coefficient between histopathological measurement and MRI was 0.837, versus 0.461 between histopathology and mammography and 0.284 between histopathology and ultrasonography. The lesion size was correctly estimated (±5 mm), under-estimated (<5 mm), or over-estimated (>5 mm), respectively, by MRI in 52.7%, 30.5%, and 16.8% of cases; by mammography in 32.0%, 51.2%, and 16.8% of cases, respectively; and by ultrasonography in 24.4%, 62.6%, and 13.0% of cases, respectively. CONCLUSION: In our study, MRI was more accurate for detection and assessment the size of DCIS compared to mammography and ultrasonography.