Computational Modeling with Fluid-Structure Interaction of the Severe M1 Stenosis Before and After Stenting / 신경중재치료의학

PURPOSE: Image-based computational models with fluid-structure interaction (FSI) can be used to perform plaque mechanical analysis in intracranial artery stenosis. We described a process in FSI study applied to symptomatic severe intracranial (M1) stenosis before and after stenting. MATERIALS AND METHODS: Reconstructed 3D angiography in STL format was transferred to Magics for smoothing of vessel surface and trimming of branch vessels and to HyperMesh for generating tetra volume mesh from triangular surface-meshed 3D angiogram. Computational analysis of blood flow in the blood vessels was performed using the commercial finite element software ADINA Ver 8.5. The distribution of wall shear stress (WSS), peak velocity and pressure was analyzed before and after intracranial stenting. RESULTS: The wall shear stress distributions from Computational fluid dynamics (CFD) simulation with rigid wall assumption as well as FSI simulation before and after stenting could be compared. The difference of WSS between rigid wall and compliant wall model both in pre- and post-stent case is only minor except at the stenosis region. These WSS values were greatly reduced after stenting to 15~20 Pa at systole and 3~5 Pa at end-diastole in CFD simulation, which are similar in FSI simulations. CONCLUSION: Our study revealed that FSI simulation before and after intracranial stenting was feasible despite of limited vessel wall dimension and could reveal change of WSS as well as flow velocity and wall pressure.

Computational Fluid Dynamics of Intracranial and Extracranal Arteries using 3-Dimensional Angiography: Technical Considerations with Physician's Point of View / 신경중재치료의학

We investigate the potentials and limitations of computational fluid dynamics (CFD) analysis of patient specific models from 3D angiographies. There are many technical problems in acquisition of proper vascular models, in pre-processing for making 2D surface and 3D volume meshes and also in post-processing steps for display the CFD analysis. We hope that our study could serves as a technical reference to validating other tools and CFD results.

Computational Flow Dynamics of the Severe M1 Stenosis Before and After Stenting / 신경중재치료의학

PURPOSE: Computational flow dynamic (CFD) study has not been widely applied in intracranial artery stenosis due to requirement of high resolution in identifying the small intracranial artery. We described a process in CFD study applied to symptomatic severe intracranial (M1) stenosis before and after stenting. MATERIALS AND METHODS: Reconstructed 3D angiography in STL format was transferred to Magics (Materialise NV, Leuven, Belgium) for smoothing of vessel surface and trimming of branch vessels and to HyperMesh (Altair Engineering Inc., Auckland, New Zealand) for generating tetra volume mesh from triangular surface-meshed 3D angiogram. Computational analysis of blood flow in the blood vessels was performed using the commercial finite element software ADINA Ver 8.5 (ADINA R & D, Inc., Lebanon, MA). The distribution of wall shear stress (WSS), peak velocity and pressure in a patient was analyzed before and after intracranial stenting. RESULTS: Computer simulation of wall shear stress, flow velocity and wall pressure before and after stenting could be demonstrated three dimensionally by video mode according to flow vs. time dimension. Such flow model was well correlated with angiographic finding related to maximum degree of stenosis. Change of WSS, peak velocity and pressure at the severe stenosis was demonstrated before and after stenting. There was no WSS after stenting in case without residual stenosis. CONCLUSION: Our study revealed that CFD analysis before and after intracranial stenting was feasible despite of limited vessel wall dimension and could reveal change of WSS as well as flow velocity and wall pressure.

High Shear Stress at the Surface of Enhancing Plaque in the Systolic Phase is Related to the Symptom Presentation of Severe M1 Stenosis

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.

Computational Flow Dynamics Study in Severe Carotid Bulb Stenosis with Ulceration / 신경중재치료의학

PURPOSE: Computational fluid dynamics (CFD) applications for atherosclerotic carotid stenosis have not been widely used due to limited resolution in the severely stenotic lumen as well as small flow dimension in the stenotic channel. MATERIALS AND METHODS: CT data in DICOM format was transformed into 3 dimensional (3D) CFD model of carotid bifurcation. For computational analysis of blood flow in stenosis, commercial finite element software (ADINA Ver. 8.5) was used. The blood flow was assumed to be laminar, viscous, Newtonian, and incompressible. The distribution of wall shear stress (WSS), peak velocity and pressure across the average systolic and diastolic blood pressures permitted construction of a contour map of the velocity in each cardiac cycle. RESULTS: Computer simulation of WSS, flow velocity and wall pressure could be demonstrated three dimensionally according to flow vs. time dimension. Such flow model was correlated with angiographic finding related to maximum degree of stenosis associated with ulceration. Combination of WSS map and catheter angiogram indicated that the highest WSS corresponded to the most severely stenotic segment at systolic phase, whereas ulceration, which is the weakest point of the plaque, appeared at the downstream side of the carotid bulb stenosis. CONCLUSION: Our preliminary study revealed that 3D CFD analysis in carotid stenosis was feasible from CT angiography source image and could reveal WSS, flow velocity and wall pressure in the severe carotid bulb stenosis with ulceration. Further CFD analysis is warranted to apply such hemodynamic information to the atherosclerotic lesion in the more practical way.

Clinical Analysis of Stage I and II Breast Cancer

PURPOSE: The combination of conservative surgery and radiotherapy is currently accepted as the preferred treatment for most patents with clinical stage I or II breast cancer. However, there is large amount of controversy concerning the optimal means of selecting patients and the details of the treatment technique. Breast cancer patients are being treated both in university hospitals and in community hospitals. Generally, the radiation therapy is not available in many community hospitals. Radiation therapy, which generally follows either a mastectomy or conservative surgery, is an important procedure. Therefore, the type of hospital facilities may influence which surgical procedures are selected. The authors conducted this study to analyse the current patterns of care for early invasive breast cancer in a hospital without a radiation therapy unit, even though the patient could receive such treatment from another affiliated hospital. METHODS: 131 cases of stage I and II breast cancer patients were reviewed between 1987 and 1997, and the types of treatments including surgery, radiation therapy and systemic therapy, were analysed retrospectively. RESULTS: The surgical procedures used were mainly a modified radical mastectomy (124/131, 94.7%), followed by breast conservation surgery (4/131, 3.1%), a total mastectomy (2/131, 1.5%) and a radical mastectomy (1/131, 0.8%). Radiation therapy was applied to 19 stage II patients (N=105), but not to any of the stage I patients (N=26). Systemic adjuvant therapy was done with chemotherapy (39/131, 29.8%), hormone therapy (17/131, 13.0%) and a combination of both modalities (67/131, 51.1%), with an exception of 8 cases. CONCLUSION: Breast conservation therapy for breast cancer patients was underutilized. The selection of the therapeutic method may be influenced by the facilities of the particular hospital. For proper treatment of early stage breast cancer, a surgeon must keep in close contact with bothe a radiologist and a radiotherapist, even in other affiliated hospitals.

Clinical Analysis of Stage I and II Breast Cancer / 한국유방암학회지

PURPOSE: The combination of conservative surgery and radiotherapy is currently accepted as the preferred treatment for most patents with clinical stage I or II breast cancer. However, there is large amount of controversy concerning the optimal means of selecting patients and the details of the treatment technique. Breast cancer patients are being treated both in university hospitals and in community hospitals. Generally, the radiation therapy is not available in many community hospitals. Radiation therapy, which generally follows either a mastectomy or conservative surgery, is an important procedure. Therefore, the type of hospital facilities may influence which surgical procedures are selected. The authors conducted this study to analyse the current patterns of care for early invasive breast cancer in a hospital without a radiation therapy unit, even though the patient could receive such treatment from another affiliated hospital. METHODS: 131 cases of stage I and II breast cancer patients were reviewed between 1987 and 1997, and the types of treatments including surgery, radiation therapy and systemic therapy, were analysed retrospectively. RESULTS: The surgical procedures used were mainly a modified radical mastectomy (124/131, 94.7%), followed by breast conservation surgery (4/131, 3.1%), a total mastectomy (2/131, 1.5%) and a radical mastectomy (1/131, 0.8%). Radiation therapy was applied to 19 stage II patients (N=105), but not to any of the stage I patients (N=26). Systemic adju-vant therapy was done with chemotherapy (39/131, 29.8%), hormone therapy (17/131, 13.0%) and a combination of both modalities (67/131, 51.1%), with an exception of 8 cases. CONCLUSION:Breast c0onservation therapy for breast cancer patients was underutilized. The selection of the therapeutic method may be influenced by the facilities of the particular hospital. For proper treatment of early stage breast cancer, a surgeon must keep in close contact with bothe a radiologist and a radiotherapist, even in other affiliated hospitals.

A Case of Adenoma Arising in a Choledochal Cyst: A case report

Bile duct adenomas are discovered incidentally during surgery or at autopsy. Especially, the occurrence of an adenoma in a choledochal cyst is very rare. Biliary carcinomas are known to be related to choledochal cysts. The association of an adenoma in a choledochal cyst with the carcinoma is not definite. We have experienced a case of a tubular adenoma arising in a choledochal cyst. Recently, a 24-year-old female was admitted with complaints of right upper quadrant abdominal pain and indigestion. Abdominal ultrasonography and ERCP showed a fusiform dilation of the common bile duct. During the operation, a tiny polyp was discovered in the cyst. We performed a cyst excision and a Roux-en-Y hepaticojejunostomy. On microscopic examination, the polyp was diagnosed as a tubular adenoma.

Clinicopathologic Findings of Early Gastic Cancer / 대한암학회지

PURPOSE: The prognosis forearly gastric cancer (EGC) is generally excellent after curative gastrectomy alone. However, the EGC of young patients was generally more invasive and metastasizing, and the prognosis of them was poorer than those of the elderly. We performed a retrospective study to evaluate clinica1 and pathological factors influencing the prognosis of EGC. MATERIALS AND METHODS: The authors investigated 66 cases of EGC resected at Inha Hospital in Song-Nam, from January 1987 to December 1996. We analyzed 9 clinicopathologic factors: age, sex, macroscopic type, tumor size, depth of invasion, location, lymph node metastasis, Williss classification and Laurens classification. RESULTS: Out of 66 cases (42 males, 24 females) of EGC, the sex ratio (M: F) was 1.75: 1, and the mean age was 55.5 years in male and 54.3 in female. The age incidence revealed a greater prevalence on 6th decade (33.3%). The most common macroscopic type of EGC was IIb and its combined type (43 cases, 65.2%). In tumor size, 16 cases (24.2%) were between 2.0 and 2.9 cm, and 13 cases (19.6%) between 1.0 and 1.9 cm, 10 cases (15%) between 3.0 and 3.9 cm. The tumors smaller than 2.0 cm were 33.2% but greater than 5.0 cm were 18.8%. In male, mucosal lesions were more common (66.6%) than submucosal lesions (33.4%); but in female, the incidence of both types of lesions were the same. The submucosal lesion in female was the most frequent at 4th decade. The major location of EGC was antrum (51.5%). Lymph node metastases were found in 3 females and 1 male. By Williss classification, poorly differentiated adenocarcinoma and signet ring cell carcinoma were more common in female (29.2%, 25%) than in male (11.9%, 14.3%). By Laurens classification, the diffuse type was more common in female (50%) than in male (33.3%). This type was the most frequent in 4th decade female patients. However, none of the above data reached statistical significance. CONCLUSION: We found the generalized tendency, though not statistically confinned, that the young female patients of EGC frequently had larger and poorly differentiated, diffuse adenocarcinomas with more frequent lymph node metastasis than male. The authors emphasizes that a further study would be needed in young female patients of EGC on hormonal factors influencing its clinicopathologic findings.

Studies on Relationship between Expression of ras , p53 , c-erbB2 and p53 and Phenotypic Expression Using Mucin Histochemistry in Human Gastric Carcinomas / 대한암학회지

PURPOSE: Recent studies have shown that the expression of mucin is organ- and cell-type specific and it is increasingly possible that its change could result from oncogene activation.To evaluate histogenesis and prognostic factors for gastric carcinoma, we studied the oncoprotein expression in gastric cancer cells classified by mucin phenotye. MATERIALS AND METHODS: Mucin histochemistry and immunohistochemistry for ras, c-erbB2, and p53 oncoprotein expression were performed in 101 surgically resected gastric carcinoma specimens. PAS-Con A, GOS, and HID-AB staining techniques were employed in identifying mucosubstances, RESULTS: Of the 101 specimens studied, 73(72.3%) revealed as having mixture of various mucin-secreting cancer cells. Overall, ras immunoreactivity was observed in 72(71.3%), c-erbB2 in 7(6.9%), and p53 in 47(46.5%). Of the 73 mucus-secreting carcinomas, the surface mucous cell type were shown in 65 (89.0%), the pyloric gland cell type in 48(65,8%), the sialomucin type in 47(64.4%), and the sulfomucin type in 54(74.0%). There was significant association between mucin secretion and ras expression, but not c-erbB2 and p53 expression. There was no significant association between mucin secreting cell types and Lauren classification. Ras expression was correlated with serosal invasion, lymph node metastasis and poor prognosis. CONCLUSION: The phenotypic expression by mucin histochemistry may be not more important for studying of histogenesis in gastric carcinoma than Lauren classification. Ras expression is a poor prognostic indicator and may be correlated with phenotypic expression of surface mucous cell and intestinal cell type in gastric carcinoma.

A Case of Acute Suppurative Thyroiditis in Pediatric Patient

Acute suppurative thyroiditis(AST) and thyroid abscess are uncommon in children. The remaining pyriform sinus tract with fistula is well known underlying abnormality of AST in pediatric patients. AST or thyroid abscess in children can be caused by infection through pyriform sinus fistulae which usually originate from the tip of the left pyriform sinus. The left-sided predominance of involvement and frequent recurrence are characteristic findings. We present a case history that include a left sided thyroid lesion of a 5-year-old girl and radiologic evidence of pyriform sinus fistula. The pus culture revealed the bacterial etiology as Staphylococcus epidermidis. Our discussion focused on the etiology and the management of AST and thyroid abscess in children.

Abdominal CT Scanning in Adult Intussusception

Intussusception is a relatively common disease in children, but it is a rare clinical entity in adults. More than 80% of all patients with intussusception are less than two years of age, but adults account for only 5 to 10 percent of all intussusception cases. The significance of this disease in the aspect of statistics is mentioned as "rule of fives", which means 5% of all intussusceptions occur in adults, and it accounts for up to 5% of all cases of bowel obstruction in adults. In children, classic symptoms include episodic abdominal pain, "current-jelly" stool and a sausage-shaped abdominal mass on examination. However, in adults, it is likely to appear with non-specific gastrointestinal trouble without classic symptoms. Therefore, it is very important to use early diagnositic tool. In contrast to childhood intussusception, which is idiopathic in 90% of cases, adult intussusception has a definable lesion in more than 90% of cases 3). Tumors, both benign and malignant, are the most frequent cause of intussusecption in adults. We experienced seven cases of adult intussusception at Inha hospital from Jan. 1994 to Dec. 1997. The patients of adult intussusception are classified as three cases of ileoileal type and four ileocecal type. There were no specific signs or symptoms with patient experienced. It included abdominal pain, diarrhea and palpable mass. Their diagnosis was made in six patients using abdominal CT scan. It is difficult to define a diagnosis preoperatively, because the symptom of adult intussusception are variable and insignificant among individuals. We had been taken the final diagnostic tool with the abdominal CT scan in six of seven patients, which revealed "target lesions" in all cases. So, it is useful in the diagnosis of adult intussusception. Bowels were resected for the treatment of adult intussusception. The extent of the resection was contained the lesion and the defunctioned segments. The operations were performed as four segmental resections of small bowel and three ileocecal resections. The pathological findings were disclosed as three tumors, three lymphadenopathies and a adhesion of bowel. We concluded that the abdominal CT scanning is a usefull diagnostic tool in the diagnosis of adult intussusception.