[en] Pipelines in power plants, nuclear facilities and chemical industries are often affected by corrosion effects. It is very important in detect such internal flaws of pipelines because they sometimes bring about serious problems. Conventional NDT methods have been taken relatively much time, money, and manpower because of performing as the method of contact with objects to be inspected. Digital shearography is a laser-based optical method which allows full-field observation of surface displacement derivatives. This method has many advantages in practical use, such as low sensitivity to environmental noise, simple optical configuration and real time measurement. In this paper, the experiment was performed with some pressure vessels which has different internal cracks. We measured internal crack length of the pressure vessels at a real time and compared with FEM simulation results.

[en] We studied the influence of proximal geometry on the results of computational fluid dynamics (CFD). We made five models of different proximal geometry from three dimensional angiography of 63-year-old women with intracranial aneurysm. CFD results were analyzed as peak systolic velocity (PSV) at inlet and outlet as well as flow velocity profile at proximal level of internal carotid artery (ICA) aneurysm. Modified model of cavernous one with proximal tubing showed faster PSV at outlet than that at inlet. The PSV of outlets of other models were slower than that of inlets. The flow velocity profiles at immediate proximal to ICA aneurysm showed similar patterns in all models, suggesting that proximal vessel geometries could affect CFD results.

[en] The computational fluid dynamics methods for the limited flow rate and the small dimensions of an intracranial artery stenosis may help demonstrate the stroke mechanism in intracranial atherosclerosis. We have modeled the high wall shear stress (WSS) in a severe M1 stenosis. The high WSS in the systolic phase of the cardiac cycle was well-correlated with a thick fibrous cap atheroma with enhancement, as was determined using high-resolution plaque imaging techniques in a severe stenosis of the middle cerebral artery.

[en] The purpose of this study is to evaluate the frequency, location, and signal intensities of parenchymal (cortical and subcortical) tubers and white matter lesion, as seen on MR images of patients with tuberous sclerosis. Twenty patients diagnosed on the basis of clinical and MR findings as suffering from tuberous sclerosis, were retrospectively reviewed. Their ages ranged from 6 days to 21 years (mean, 5.2 years), and they were divided into two groups according to age : under 18 months (n=9) and over 18 months (n=11). We analyzed the frequency, location, and enhancement patterns of tubers and white matter lesions, and the difference of signal intensities between cortical and subcortical tubers according to age. Both cortical and subcortical tubers were commonly located in the frontal lobe, but the latter were more frequently observed than the former. Subcortical tubers by MR imaging may therefore help analyze the parenchymal tubers seen in tuberous sclerosis. (author). 12 refs., 2 tabs., 4 figs

[en] To compare modified small bowel follow-through (SBFT) using methylcellulose after the administration of barium suspension with a conventional series. Materials and Methods : In order to evaluate small bowel pathology, modified SBFT was performed in 155 patients during a 15 month period. All patients received 600 mL of methylcellulose ; 98 had taken 250 mL of 40% wt/vol barium suspension and 57 had taken 150 mL of 70% barium. For the group of 98, the barium suspension was prepared by mixing barium powder with water (n=46) or with methylcellulose in(n=52). For comparison with a modified series, 49 patients who underwent conventional SBFT using 500 mL of 40 %wt/vol barium were lso included. Image quality was rated by three radiologists as ^poor^,fair^,good^, or^excellent^. We analyzed the relationship between image quality, transit time and small bowel pathology;the sensitivity and specificity of each technique was also determined. Results : Among the four techniques, modified SBFT with 250 mL of 40% wt/vol barium suspension, prepared by mixing barium powder with methylcellulose, showed the best image quality ['excellent' result in 33 of the 52 patients (63%)] and shortest transit time to the cecum. The high image quality of this technique was not affected by the presence of small bowel pathology;its use resulted in the lowest incidence and slowest development of flocculation. The sensitivity (91-95%) of the three modified SBFT procedures was superior to that of a conventional series(76%), but there was no difference in specificity.Conclusion : Modified SBFT using methylcellulose after administering barium suspension with barium powder as a mixing agent is a simple technique. Its use easily improves the image quality and diagnostic accuracy of peroral SBFT

[en] Pipelines in power plants, nuclear facilities and chemical industries are often affected by corrosion effects. The inspection of internal defects of these pipelines is important to guarantee safe operational condition. Conventional NDT methods have been taken relatively much time, money, and manpower because of performing as the method of contact with objects to be inspected. Digital shearography is a laser-based optical method which allows full-field observation of surface displacement derivatives. This method has many advantages in practical use, such as low sensitivity to environmental noise, simple optical configuration and real time measurement. Therefore it is a good method to use for detecting internal defects. In this paper, the experiment was performed with some pressure vessels which has different internal cracks. We detected internal cracks of the pressure vessels at a real time and evaluated qualitatively these results. We also performed qualitative measurement of shearo fringe by using phase shifting method.

[en] To determine the location and distribution, as seen on cerebral angiograms, of severe atherosclerotic stenosis of atherosclerotic or occlusion among Koreans and to thus be aware of the differences in distribution of these conditions between Koreans and other ethnic groups included in previously reported data. We retrospectively reviewed the cerebral angiographic findings of 268 patients in whom angiography had revealed at least one instance of severe stenosis (ss) (>70%) and who had more than one risk factor for atherosclerosis. The review was focused on the location of the stenosis and multiplicity of the lesion. Statistical analysis employed the chi-square test, and the data obtained was compared with that reported for other ethnic groups. A total of 389 SS sites were detected in 268 patients. Isolated severe stenosis (IS) was found in 56 patients (21%), and multiple stenoses (MS) in 212 patients (79%). Lesions were located in the intracranial portion in 52% of cases, and in the extracranial portion in 48%(p>.05). They were found in the anterior circulation in 59% and in the posterior circulation in 41%(p<.05). Thirty-seven of 56 IS (66%) were located in the intracranial portion and 19 (34%) in the extracranial portion (p<.05). One hundred and sixty-seven(50%) of 333 lesions involving multiple stenoses were seen in the extracranial portion, while 166 (50%) were located in the intracranial vessels. The higher prevalence of intracranial stenosis in the IS group than in the MS group was statistically significant(p<.05). On the basis of previously reported data, Korean patients with severe atherosclerotic stenosis tend to have more frequent multiple and intracranial stenoses than do Caucasians. Intracranial stenosis was more frequent in the isolated stenosis group than in the multiple stenosis group

[en] Anisakiasis of the duodenum has been observed infrequently. Moreover, there has been no report of concurrent occurrence of small bowel obstruction and fistula formation for duodenal anisakiasis. We describe an interesting and instructive case of a patient with duodenal anisakiasis consisting of small bowel obstruction and fistula formation. The differential diagnosis was performed by observing the morphological patterns more closely with the use of CT imaging, MR imaging and an upper gastrointestinal (UGI) series

[en] Metastatic melanoma to the pancreas has been observed infrequently, and the presence of a thrombus in the splenic vein and superior mesenteric vein has rarely been seen for metastatic melanoma. We present the CT and MRI findings of a case of metastatic melanoma to the pancreas, which presented with diffuse multiple pancreatic metastatic nodules and a venous thrombus

[en] The purpose of this study was to evaluate the feasibility, efficacy and safety of percutaneous thromboaspiration with a Desilets-Hoffman Sheath compared with the previously established percutaneous mechanical thrombectomy technique in cases of occluded dialysis graft. One hundred and sixty eight patients (103 women, 65 men; mean age, 54.7 years; mean graft age, 20.9 months) with 225 episodes of dialysis graft thrombosis underwent percutaneous thromboaspiration with a 7F Desilets-Hoffman sheath using the crossing catheter or single puncture technique. The technical success rate, procedure time, and complication and patency rates were analyzed. Technical success was achieved in 200 of the 225 procedures (88.9%). The average duration of the intervention was 74.3 ± 35 minutes. The primary patency rate was 63.1% at 3 months, 44.2% at 6 months and 26.3% at 1 year. Major complications occurred in 4% of the cases (4 venous ruptures; 4 arterial embolisms; 1 arterial rupture) and minor complications occurred in 13.8% of the cases (26 minor venous ruptures; 4 intragraft ruptures; 1 venous dissection). These results were quite similar to those obtained with the previous mechanical thrombectomy technique. Percutaneous thromboaspiration of occluded dialysis grafts with a Desilets-Hoffman Sheath is an effective and safe method