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Biomedical subjects

J K Han

Publications and source records attributed to J K Han.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

MRI of clonorchiasis and cholangiocarcinoma.

Intrahepatic cholangiocarcinomas are usually categorized as peripheral cholangiocarcinoma or hilar cholangiocarcinoma on the basis of the site of origin. Clonorchiasis is a trematodiasis caused by chronic infestation of liver flukes, which are largely confined to the Orient, from Japan to Vietnam. The close relationship between clonorchiasis and cholangiocarcinoma has long been emphasized. This paper discusses the efficacy and possible roles of MRI for imaging clonorchiasis and cholangiocarcinoma of the liver. Although sonography, CT, and direct cholangiography have been used traditionally to diagnose these diseases, the role of MRI has been increasing rapidly with dramatic progress of the MRI techniques. We review MRI findings of clonorchiasis and cholangiocarcinoma and discuss the potential usefulness of MRI.

Bile Duct Diseases↗
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T2-weighted breath-hold MRI of the liver at 1.0 T: comparison of turbo spin-echo and HASTE sequences with and without fat suppression.

To compare the clinical usefulness of T2-weighted breath-hold sequences for imaging the liver, 33 patients with 97 focal hepatic lesions were studied with a 1.0-T scanner by using T2-weighted breath-hold turbo spin-echo (SE) sequences and T2-weighted breath-hold half-Fourier single-shot turbo SE (HASTE) sequences with and without fat suppression. Images were quantitatively analyzed for liver signal-to-noise ratio (SNR) and lesion-to-liver contrast-to-noise ratios (CNR). Qualitative analysis was performed for lesion conspicuity, motion artifacts, and anatomic sharpness of extrahepatic structures. Breath-hold turbo SE imaging with fat suppression showed the highest CNR for cystic lesions and the best lesion conspicuity for cystic and solid lesions among the four sequences. For solid lesions, there was no significant difference of lesion-to-liver CNR between them. HASTE sequence was superior to turbo SE sequences in terms of motion artifacts; however, the usefulness for evaluating focal hepatic lesions was limited compared with turbo SE sequence with fat suppression. Addition of fat suppression was not helpful for HASTE imaging because of decreased lesion conspicuity and extrahepatic details without the advantage of reducing motion artifacts. This study suggests that turbo SE sequence with fat suppression is most useful for breath-hold T2-weighted liver imaging at 1.0 T. Addition of imaging without fat suppression can be considered for evaluating extrahepatic structures. HASTE sequence may have a role for imaging uncooperative patients due to absence of motion artifacts.

Abscess↗
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Perforation of the gastroduodenal artery induced by steerable guidewires in two cases: treatment of hemorrhage by embolization.

We encountered 2 cases of guidewire-induced perforation of the gastroduodenal artery after using a hydrophil-coated guidewire. The guidewire penetrated a small side branch of the normal gastroduodenal artery in 1 patient and the weakened gastroduodenal artery due to pancreatic pseudocyst in the other patient. Both complications resulted in serious hemorrhage and were successfully managed by transcatheter embolization using steel coils. In an era of widespread use of hydrophil-coated guidewires for superselective catheterization, it is important to appreciate the possibility of this potentially serious complication.

Aged↗
PubMedDate not supplied

Cystic peripheral cholangiocarcinoma: sonography and CT.

A case of cystic peripheral cholangiocarcinoma is presented. Both sonography and computed tomography (CT) demonstrated a large intrahepatic cystic neoplasm containing an enhancing solid portion. Despite the very rare incidence of this tumor, we believe that cystic degeneration of peripheral cholangiocarcinoma should be considered with these radiologic findings.

Bile Duct Neoplasms↗
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Peripheral cholangiocarcinoma: comparison of MRI with CT.

To evaluate the clinical utility of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of peripheral cholangiocarcinoma of the liver, 11 patients with pathologically proven peripheral cholangiocarcinoma were examined with both CT and MRI. On CT scans in 10 cases, the tumors appeared as irregular, low-attenuation masses with a wide variation in heterogeneity. Contrast enhancement of the tumors was mild in nine cases and moderate in one case, at the periphery. Tumor was not identified in one case. On T1-weighted MRIs, the tumors showed low intensity in eight cases and isointensity in three cases. On T2-weighted images, the tumors showed high intensity in all 11 cases. Focal dilatation of the intrahepatic bile ducts around the tumor was seen in one case on MRIs and in four cases on CT scans. Portal vein invasion of the tumors was seen in one case, and lymphadenopathy was seen in four cases on both MRIs and CT scans. MRI was slightly superior to CT in detecting the tumors, was inferior to CT in delineating focal ductal dilatation around the tumors, and was equal to CT in assessing extent of the tumors.

Aged↗
PubMedDate not supplied

Colitis in Behçet's disease: characteristics on double-contrast barium enema examination in 20 patients.

We performed a retrospective review of double-contrast barium enema examinations of 20 patients with clinically proven Behçet's colitis. Main lesion was ovoid or geographic ulcers with a mean diameter of 2.7 cm. The number of ulcers was single in 15 cases and multiple in five. On six resected specimens, ulcers involved submucosa in three, muscle layer in one, and serosa in two cases with an undermining tendency and transmural inflammation. Aphthous ulcers were present in three cases. Neither perforation nor fistula was demonstrated. In all 20 patients, the ulcer was localized in the ileocecal area, with extension to the ascending colon in seven. Skip lesions were observed in the transverse colon and descending colon in three cases. Destruction of surrounding mucosa resulted in cecal contraction in 19 cases, widening of the ileocecal valve in 19, and fold thickening in the terminal ileum in 12. Six cases (30%) manifested as ileocecal mass accompanied by ulcer, fold thickening, and adjacent mucosal deformity. The appendix was visualized in only three (20%) of the 15 patients with no history of appendectomy. On follow-up study of 15 cases, the ulcers disappeared or decreased in size in 13 cases (86%) and the mucosal deformity was not improved in all cases. On the basis of our results, we believe that the characteristic findings of colitis in Behçet's disease in barium enema examination are ovoid or geographic, relatively large, and deep ulcerations with persistent surrounding deformity which tend to localize in the ileocecal area.

Adolescent↗
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Transcatheter arterial embolization of unresectable renal cell carcinoma with a mixture of ethanol and iodized oil.

PURPOSE: The effectiveness of renal transcatheter arterial embolization (TAE) with a mixture of ethanol and iodized oil (Lipiodol) was analyzed retrospectively in 27 patients with unresectable renal cell carcinoma. METHODS: Symptomatic or permanent palliation by TAE was performed with the intent to achieve total or partial ablation of the kidney with 10-28 ml of embolic material in a 3:1 mixture of ethanol and iodized oil. Clinical, angiographic, and computed tomographic (CT) follow-up were analyzed. Cumulative survival was estimated with the Kaplan-Meier method. RESULTS: Partial (5) or complete (22) ablation of the embolized kidneys was achieved in all cases. Follow-up CT after 1 month revealed Lipiodol uptake in the tumor area (14/14), decreased size of the tumor (6/14), and gas formation (7/14). Pulmonary metastasis improved significantly in one patient after transcatheter arterial embolization and adjunctive chemotherapy. Overall median survival of the 27 patients was 8.5 months. The median survival was 23 months in 10 patients with stage III, three of whom are still alive, and was 7 months in 15 patients with stage IV tumors. CONCLUSION: The mixture of ethanol and Lipiodol is not only a convenient embolic material to use, but is also effective for selective or nonselective devascularization for unresectable renal cell carcinoma.

Adult↗
PubMedDate not supplied

Combined hepatocellular and cholangiocarcinoma of the liver: sonography, CT, angiography, and iodized-oil CT with pathologic correlation.

To evaluate the characteristics of combined hepatocellular and cholangiocarcinoma of the liver by imaging techniques, six patients (five male and one female), aged 46-60 years, with proved combined tumors were selected for this study from the review of 500 resected specimens of liver tumors. Images obtained from sonography, computed tomography (CT), angiography, and CT after intraarterial injection of iodized oil (iodized-oil CT) were retrospectively reviewed and correlated with the appearance of pathologic specimens. Sonographic findings were round or ovoid hypoechoic masses with central hyperechoic area (target appearance) in all patients. On CT scans, tumors were relatively well-defined low-and/or iso-attenuation masses in all patients. Angiography showed hypovascular masses in five patients. In one patient, the tumor appeared as a hypovascular mass with a central hypervascular area. On iodized-oil CT scans, all patients showed partial retention of iodized oil in tumors. Echogenicity in tumors at sonography or attenuation in tumors at CT could not be correlated with histologic difference in tumors at pathologic specimens. However, the hypervascular area at angiography and the compact retention areas of iodized oil at iodized-oil CT corresponded to portions of hepatocellular carcinoma within the combined tumor. On the basis of our results, imaging features, including target appearance at sonography, hypovascular mass with central hypervascular portions at angiography, and partial retention of iodized oil in tumors at iodized-oil CT, might be helpful in making accurate diagnosis of these rare tumors.

Carcinoma, Hepatocellular↗
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Postoperative recurrence of hepatocellular carcinoma: results of transcatheter arterial chemoembolization.

A retrospective analysis was made of the effect of transcatheter arterial chemoembolization (TACE) in 87 patients with recurrent hepatocellular carcinoma (HCC). In contrast to the predominantly single nodular HCC (60.2%) on preoperative angiography, recurrent HCC showed a multinodular pattern in 54.2%. Preoperative TACE had significantly prolonged the interval between surgery and recurrence. One- and 2-year survival rates after TACE of the 87 recurrent HCCs were 74.7% and 55.%, respectively, which were not significantly different from those of a control group of 206 patients with HCC in Child's class A, who were treated with TACE only. We believe that TACE is an effective measure in the management of preoperative and recurrent HCC.

Adolescent↗
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Iatrogenic dissection of the celiac artery and its branches during transcatheter arterial embolization for hepatocellular carcinoma: outcome in 40 patients.

PURPOSE: To study the sequelae of iatrogenic dissection of the celiac axis and its branches in a large patient population. METHODS: We analyzed 40 patients with hepatocellular carcinoma (HCC) whose celiac artery or its branches were dissected during transcatheter arterial embolization (TAE) and underwent follow-up angiography within 2 months. RESULTS: The two most common sites of dissection were the celiac artery in 13 patients (32.5%) and the proper hepatic artery in 11 patients (27.5%). Follow-up angiography revealed complete recanalization in 32.5% (13/40), irregularity and narrowing of the lumen in 40% (16/40), and complete obstruction in 27.5% (11/40). Therefore, 72.5% (29/40) of the dissected arteries recanalized. Pseudoaneurysm formation of the dissected artery was observed in 32.5% (13/40). Subsequent TAE was possible via the dissected arteries in 79% (27/34) of patients in this series. CONCLUSION: Iatrogenic dissection of the celiac and proximal hepatic arteries heals spontaneously in the majority of patients, and in most instances allows subsequent TAE.

Adult↗
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Acute hepatic vein occlusion: spiral CT findings in an experimental study.

BACKGROUND: We investigated spiral computed tomographic (CT) findings and underlying hemodynamic alterations in acute hepatic vein occlusion. METHODS: In nine dogs, immediately after balloon occlusion of the right ( n = 4) or left ( n = 5) hepatic vein through the transjugular or transfemoral route, we performed single-level dynamic CT with intravenous administration of contrast medium. We created time attenuation curves of individual hepatic segments showing attenuation differences. To investigate underlying hemodynamic alterations, hepatic arteriograms were obtained in two dogs. RESULTS: In all cases, there were three compartments with different time attenuation curves: normal, occluded, and adjacent. The normal compartment, which comprised segments far from the occluded hepatic compartment, showed the normal pattern of hepatic enhancement. The occluded compartment, which was the drainage territory of the occluded hepatic vein, showed high attenuation in the early arterial phase and low attenuation in the portal phase. The adjacent compartment, which shared the same portal vein with the occluded compartment and was drained by the patent hepatic vein adjacent to the occluded one, showed strong contrast enhancement in the late arterial and early portal phase. Spiral CT and hepatic arteriography demonstrated the arterioportal shunt and reversed portal venous flow in the occluded compartment, which drained into the adjacent compartment. CONCLUSION: Acute hepatic vein occlusion on spiral CT appears as mild, early arterial, high attenuation and portal low attenuation of the occluded compartment and strong enhancement in the late arterial and early portal phases of the adjacent compartment due to arterioportal shunt and reversed portal flow.

Acute Disease↗
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Biliary obstruction in metastatic disease: thin-section helical CT findings.

BACKGROUND: We describe the thin-section helical computed tomographic (CT) findings of biliary obstruction caused by metastasis. METHODS: Thin-section helical CT (5 mm slice thickness, 1:1 pitch, portal phase) and direct cholangiography in 50 consecutive patients with biliary obstruction caused by metastases were reviewed retrospectively by three radiologists. The primary sites were the stomach ( n = 36), colon ( n = 12), jejunum ( n = 1), and uterus ( n = 1). The level of biliary obstruction was analyzed with the Bismuth classification, and the CT findings of biliary obstruction were classified into six types: small (<2 cm) periductal masses, large (>/=2 cm) periductal masses, extrinsic compression by a metastatic liver mass, high-attenuation intraductal mass, intrapancreatic mass, and no demonstrable lesion. RESULTS: The level of biliary obstruction was the hilum in 18 patients (36%), the proximal common duct in 20 (40%), the distal common duct in five (10%), and the periampullary area in seven (14%). Of 18 hilar obstructions, tumor involvement of the secondary confluence of intrahepatic bile ducts was seen in 10 (right in six, left in one, and bilateral in three). Periductal masses were seen in 68% (small in 18, large in 16). In one patient (2%), a large metastatic mass of the liver resulted in extrinsic compression and biliary obstruction. Lesions mimicking primary biliary or pancreatic tumor were seen in four, respectively. In seven, we found no obstructing lesion on CT. CONCLUSION: Biliary obstruction in patients with known primary malignancies can show atypical patterns mimicking primary pancreatobiliary malignancies on thin-section helical CT.

Adult↗
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Focal eosinophilic infiltration in the liver: radiologic findings and clinical course.

BACKGROUND: We investigated the radiologic findings and clinical course of focal eosinophilic infiltration in the liver. METHODS: We retrospectively reviewed computed tomographic (CT) and sonographic scans in 20 patients (18 male, two female; mean age, 50 years) with pathologically or clinically proven focal eosinophilic infiltration in the liver by two experienced radiologists in our institute from August 1995 to June 1999. We also correlated radiologic findings with peripheral eosinophil count. Radiologic and clinical findings during the follow-up (range, 2-49 months; mean, 19.5 months) also were analyzed. RESULTS: Clinical symptoms and signs included abdominal pain (n = 4), easy fatigability (n = 3), weight loss (n = 1), and peripheral eosinophilia (n = 19). Twelve patients were asymptomatic. On sonographic examinations, all lesions were seen as focal, low echoic nodules. On CT, the lesions appeared isoattenuated or low attenuated in the arterial phase and low attenuated in the portal phase, except one case that showed high attenuation in the arterial phase. The margins of most lesions appeared poorly defined. Lesions were single (n = 9) and multiple: two to five (n = 6), six to 10 (n = 3), and more than 10 (n = 2). Each lesion was smaller than 2 cm; only one was 4 cm in diameter. The distribution of the lesion was subcapsular in 14 patients and central in five. Diffuse dissemination was observed in one. Eosinophil-associated abnormality was not present in other abdominal organ in all cases. The peripheral eosinophil count correlated closely with the number but not with the size of lesions. Sixteen patients who had follow-up images showed complete (n = 14) or partial regression of the lesions with a decrease in size (n = 1) or number (n = 1) after 2-22 months (mean, 6.4 months). CONCLUSION: Focal eosinophilic infiltration in the liver had somewhat characteristic radiologic findings on sonography and CT. In the correct clinical context of peripheral eosinophilia and self-limited course, these radiologic findings may be helpful in differentiating this condition from other focal hepatic lesions.

Contrast Media↗
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Subphrenic bronchogenic cyst mimicking a juxtahepatic solid lesion.

Most bronchogenic cysts occur in the mediastinum. However, they may be found near any organ derived from the embryonic foregut, even in the extrathoracic region. We report a case of subphrenic bronchogenic cyst that was initially confused with a solid lesion because of its unusual location and atypical appearance on ultrasonography, computed tomography, and magnetic resonance imaging.

Bronchogenic Cyst↗
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Afferent loop obstruction after gastric cancer surgery: helical CT findings.

BACKGROUND: We reviewed the computed tomographic (CT) findings of afferent loop obstruction and assessed the value of helical CT in determining the underlying cause. METHODS: Helical CT scans of 18 patients (12 men and six women; age range = 35-67, mean age = 50 years) with afferent loop obstruction were reviewed. All patients had gastric cancer. Ten patients had undergone radical subtotal gastrectomy with Billroth II gastrojejunostomy, and eight had undergone total gastrectomy with Roux-en-Y esophagojejunostomy. CT images were analyzed retrospectively, and the presumed cause of obstruction on CT was compared with surgical findings (n = 8) and clinical courses (n = 10). RESULTS: Local recurrence (n = 15), peritoneal seeding (n = 1), internal hernia (n = 1), and adhesion (n = 1) were the presumed causes of obstruction on CT. In all eight patients who underwent a second operation, the cause of afferent loop obstruction was correctly suggested on CT (local recurrence in six patients and adhesion and internal hernia in one patient). In 10 patients who were not re-explored, the clinical findings or biopsy indicated recurrent tumor as suggested on CT. CONCLUSION: Recurrent tumors and other potential causes of afferent loop obstruction can be correctly predicted with CT in most cases.

Adult↗
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Contrast-enhanced dynamic ultrasonography of the liver: optimization of hepatic arterial phase in normal volunteers.

BACKGROUND: To optimize hepatic arterial phase timing in contrast-enhanced dynamic ultrasonography (US) of the liver. METHODS: Dynamic US was performed by using a microbubble-specific mode in 22 healthy volunteers after bolus injection of SH U 508A. Images were analyzed to determine whether hepatic arterial and portal venous phases could be temporally discriminated. Delay times to contrast enhancement at the hepatic artery (A(ini)) and portal vein (P(ini)) and the delay time until the signals between both vessels became inseparable (A(end)) were determined. RESULTS: The hepatic arterial and portal venous phases could be temporally discriminated in all subjects. A(ini), P(ini), and A(end) (mean +/- standard deviation) were 11.0 +/- 2.0, 14.8 +/- 3.6, and 22.6 +/- 5.1 s, respectively. CONCLUSION: In hepatic contrast-enhanced dynamic US, hepatic arterial phase scanning should be commenced earlier than 11 s and terminated after 23 s postinjection.

Adult↗
PubMedDate not supplied

Helical CT of postoperative patients with gastric carcinoma: value in evaluating surgical complications and tumor recurrence.

BACKGROUND: We assessed computed tomographic (CT) features of postoperative complications and recurrent tumors in gastric cancer patients who underwent radical surgery. METHODS: We performed a retrospective study of 397 patients who had undergone radical surgery for the treatment of gastric carcinoma and underwent postoperative CT in our institution over a 2-year period. Patients were assigned to one of two groups: group A consisted of 47 patients who underwent CT for complications in the early postoperative period, and group B consisted of 355 patients who underwent CT for evidence of tumor recurrence during the follow-up period. We classified recurrent tumors into four categories: local recurrence, lymph node metastasis, peritoneal seeding, and remote metastasis. RESULTS: In group A, localized fluid collections or abscesses in the surgical bed were found in 38 patients (81%) and usually involved the left subphrenic area (74%) or the superior recess of the lesser sac (47%). In group B, recurrent tumors were found in 196 patients (55%). Among these, lymph node metastasis was the most common pattern (52%), followed by peritoneal seeding (44%), local recurrence (40%), and remote metastasis (37%). CONCLUSION: CT after radical surgery for the treatment of gastric carcinoma frequently shows postoperative complications or tumor recurrence. Familiarity with the common postoperative complications and patterns of the tumor recurrence is a prerequisite to accurate interpretation of CT findings in these patients.

Adult↗