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Biomedical subjects

M C Han

Publications and source records attributed to M C Han.

At least 181 records · Page 10Linked to original sources
PubMed1987

Mediastinal tuberculous lymphadenitis: CT manifestations.

An analysis was done of computed tomographic (CT) scans of 23 Korean patients who had presented with a mediastinal or hilar mass on plain chest radiographs and had subsequently been found to have tuberculous lymphadenitis. Most patients were young adults. Findings of pulmonary tuberculosis were seen on plain radiographs in 14 patients. On CT, findings were of an overwhelming preponderance of involvement of the right paratracheal and tracheobronchial nodes. After injection of contrast medium, nodes larger than 2 cm in diameter invariably showed central areas of relative low density and peripheral rim enhancement. Enhanced walls were usually irregular in thickness. Some smaller nodes did not show low-density areas, but instead showed varying degrees of homogeneous enhancement. Although metastatic nodes can be of low density, experience in this study suggests that mediastinal lymphadenopathy in a young adult with the CT findings described above is characteristic enough to support a diagnosis of tuberculosis.

Adolescent↗
PubMed1987

Percutaneous pulmonary valvuloplasty with a double-balloon technique.

Percutaneous pulmonary valvuloplasty with a double-balloon technique was used in eight patients, aged 10-40 years, in whom valvuloplasty with a single 20-mm balloon resulted in inadequate dilatation of the stenosis. The diameters of the additional balloon varied from 10 to 20 mm. Balloons were inflated manually at about 30-45 psi (206.7-310.1 kPa) and deflated immediately after disappearance of the balloon waist. The mean peak systolic pressure gradient was 85 mm Hg +/- 37 before valvuloplasty, and it decreased to 38 mm Hg +/- 28 afterward (P less than .05). Double-balloon dilation and simultaneous computed tomography were done in two cardiac specimens from adult cadavers. At inflations at 30 and 45 psi (206.7 and 310.1 kPa), the outflow tract was elongated, and the balloons also deformed into ovoid shape at the lower pressure. The double-balloon technique appears to be safe and effective for relief of pulmonary valvular stenosis in those cases in which single-balloon technique is inadequate, especially in older children and adults.

Adolescent↗
PubMed1987

Cerebral sparganosis: CT characteristics.

Cerebral sparganosis is an extremely rare parasitic zoonosis caused by a migrating plerocercoid tapeworm larva, genus Spirometra. Nineteen computed tomography (CT) scans of 12 patients with cerebral sparganosis were retrospectively analyzed and correlated with clinical and pathologic data. On CT scans, the following characteristics were noted: (a) unilateral involvement; (b) extensive or multifocal areas of low density along white matter bundles, with ipsilateral ventricular dilatation and localized cortical atrophy; (c) nodular or irregular enhancement with spotty calcification; and (d) change in location of enhancing nodules on sequential scans. These pathognomonic features reflect a chronic inflammatory process with both active granulomatous lesions and widespread degeneration of brain tissue, especially in the white matter. Degeneration is probably caused by migration of the long-surviving larva along the fiber tracts of white matter.

Adult↗
PubMed1987

The inferior accessory hepatic fissure: sonographic appearance.

The inferior accessory hepatic fissure, a coronal or parasagittal fissure through the parenchyma of the posterior segment of the right hepatic lobe, was observed sonographically in 15 of 2000 patients. The fissure was seen as a thin, echogenic membrane stretching downward from the right branch of the portal vein to the inferior surface of the right hepatic lobe. On cadaveric sections, the fissure was an invagination of peritoneum directed laterally and slightly posteriorly from the medial inferior surface of the right hepatic lobe below the porta hepatis.

Humans↗
PubMed1987

Renal arterial embolization with absolute ethanol.

Twenty separate infarction procedures with absolute ethanol were performed on eighteen renal tumors in seventeen patients at Department of Radiology, Seoul National University Hospital since 1982. Fifteen were hypernephroma cases and two were angiomyolipoma cases. The indications for renal infarction were the preoperative interruption of renal arterial flow in eight cases of hypernephroma, and primary therapy or palliation of symptoms in seven cases of hypernephroma and two cases of angiomyolipoma. Average 15ml of absolute ethanol was injected for renal arterial embolization at a rate of 1-2 ml/sec via balloon occlusion catheter or superselective administration technique. Though the long-term beneficial effect on survival was not confirmed, transcatheter embolization with absolute ethanol was suggested to be used as indispensible treatment in preoperative and inoperable or symptomatic cases of renal tumor.

Embolization, Therapeutic↗
PubMed1987

Magnetic resonance imaging in neurologic diseases--comparison with computed tomography.

Magnetic resonance (MR) and computed tomography (CT) imagings were compared in 121 patients with various neurologic diseases. MR was performed with either 0.15 Tesla resistive or 2.0 Tesla superconducting systems developed by Korea Advanced Institute of Science and Technology (KAIST), using multi-slice spin echo technique with a variety of pulse sequences reflecting proton density, T1 and T2 relaxation times. MR was more advantageous in the detection of the lesions, accurate depiction of the lesion extents, and/or demonstration of anatomic details in sagittal or coronal plane in 36 of the 121 patients. These included white matter diseases, cervical cord tumors, syringomyelia, brain stem tumors, foramen magnum tumor, acute cerebellar infarction, Chiari malformation, isodense subacute subdural hematomas, cavernous hemangioma, A-V malformation with hemorrhage and some unknown pathologies. Even though 2.0T superconducting system showed greater capability of demonstrating the anatomic details and contrast discrimination between normal and abnormal tissues, the ability of MR to separate the tumor from the edema and to differentiate among different pathologic entities remained to be further evaluated. CT was superior to MR in 13 patients with acute intracranial hematomas, small calcific lesions, inflammatory granulomas or meningiomas. CT takes less time and may be preferable in very young or elderly patients. Both MR and CT gave equivalent information in the remaining patients. MR proved to complement CT in the evaluation of many disease entities and may actually supplant CT in some.

Brain↗
PubMed1986

Transcatheter renal arterial embolization with the mixture of ethanol and iodized oil (Lipiodol).

We induced experimental renal arterial embolization with the radiopaque solution of ethanol and iodized oil (Lipiodol) in 35 rabbits to evaluate the capability of the mixture to induce renal ablation. Serial renal angiography and plain abdominal radiography were performed immediately, one week and two weeks after embolization. Neither pure Lipiodol nor a 50% ethanol solution caused renal embolization. However, infusion of 50% and 75% ethanol-Lipiodol solutions resulted in embolization equal to that caused by absolute ethanol. The 50% ethanol-Lipiodol solution was so radiopaque that we could easily observe the embolization process during fluoroscopy. Renal arterial embolization with the 50% ethanol-Lipiodol solution was successful in three patients with hypernephroma. Our results suggest that a 50% ethanol-Lipiodol solution is radiopaque and an effective agent for renal arterial embolization.

Animals↗
PubMed1985

Sonographic evaluation of inferior vena caval obstruction: correlative study with vena cavography.

Sonographic findings of obstruction of the inferior vena cava (IVC) in 14 cases are described and correlated with venographic findings. The causes of the obstruction were membrane (five cases), thrombosis (three), and intraluminal tumor invasion by hypernephroma, hepatoma, and adrenal carcinoma in six. Sonographic examination revealed highly echogenic segmental obliteration or membrane in membranous obstruction and echogenic intraluminal mass in thrombotic occlusion. Absence of an identifiable patent lumen in a technically satisfactory study was another finding in thrombotic obstruction. On real-time sonograms, the normal respiratory changes of the IVC were absent when there was complete occlusion. Transhepatic collaterals, patency of other segments of the IVC, and associated malignancy were additional sonographic findings. Comparison to venography suggested that in addition to ease and safety, sonography has advantages in delineation of the cephalad extent of occlusion, dynamic evaluation of the IVC below the obstruction, and the simultaneous evaluation of adjacent organs.

Constriction, Pathologic↗
PubMed1984

Arterial manifestations of Behçet disease.

Behçet disease is an uncommon systemic process that appears most often in the third or fourth decade of life. It is characterized by recurrent orogenital ulcers and ocular and cutaneous inflammatory lesions. Cardiovascular involvement, which may be arterial or venous, is rare but carries a particularly poor prognosis. Three new cases are reported, and they are characterized by typical orogenital and cutaneous manifestations and associated severe vasculitis. The arterial findings in these cases were occlusions and aneurysms and pseudoaneurysms of the aorta and pulmonary, brachiocephalic, and visceral arteries. From these cases and those previously reported, arterial involvement in Behçet disease can be characterized by saccular aneurysms or occlusions of multiple large vessels in young adults.

Adult↗
PubMedDate not supplied

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

MR findings of hepatic cavernous hemangioma after intraarterial infusion of iodized oil.

Magnetic resonance (MR) imaging was performed on five tumors of three patients who had hepatic hemangiomas. Four tumors were given an intraarterial infusion of 3-8 ml of iodized oil, while one tumor was not. MR images were obtained at 2.0 or 0.5 T. A single spin echo sequence with TE of 30 ms and TR of 500 ms and a double echo sequence with TEs of 60 and 150 ms and TR of 2000 ms, were used to produce relatively T1-, T2-weighted, and heavily T2-weighted images, respectively. Follow-up MR imaging was done 1-5 months after infusion of iodized oil. On relatively T1-weighted images, hemangiomas showed iso- or hypointensity. On T2-weighted images, all tumors showed hyperintensity. However, on heavily T2-weighted images, tumors with iodized oil showed heterogeneous, slight hyperintensity, while tumors without iodized oil showed characteristic appearance of marked hyperintensity in hemangiomas. In hepatic cavernous hemangiomas with intraarterial infusion of iodized oil, familiarity with this unusual MR intensity of tumors on heavily T2-weighted images is useful to avoid the incorrect diagnosis and to reduce the frequency of inappropriate hepatic resection.

Female↗
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↗
PubMedDate not supplied

Undifferentiated embryonal sarcoma of the liver treated with chemotherapy: CT imaging in four patients.

BACKGROUND: The purpose of this study was to describe the computed tomography (CT) findings of undifferentiated embryonal sarcoma after chemotherapy and to correlate the CT imaging findings with pathologic findings. METHODS: Ten CT images obtained before and after chemotherapy in four patients with hepatic undifferentiated embryonal sarcoma were retrospectively reviewed and correlated with pathologic findings. RESULTS: After chemotherapy, tumor volume decreased by 50-90% and initially nonresectable tumor or gross residual tumor was successfully excised in three patients. In all patients, enhancing peripheral solid portions and septations changed to low-attenuation areas, and in three patients increased or de novo calcifications were found at the periphery of the tumor. Resected pathologic specimen after chemotherapy showed well-encapsulated masses with central necrosis, fibrosis, and dystrophic calcifications. CONCLUSIONS: These CT findings will be useful in monitoring the treatment response of hepatic undifferentiated embryonal sarcoma during chemotherapy.

Adult↗
PubMedDate not supplied

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

Castleman disease with renal amyloidosis: imaging findings and clinical significance.

We report two cases of renal amyloidosis associated with mesenteric and mediastinal Castleman disease of plasma cell type. Computed tomographic (CT) scan revealed a mesenteric mass with multiple nodal enlargement in one patient and a right paratracheal mass with irregular central calcifications in the second patient. Renal ultrasonography (US) showed increased echogenicity of the renal parenchyma with prominent medullas. Doppler waveform obtained in the kidney associated with mesenteric disease showed complete absence of diastolic flow signal, although it was normal in the patient with mediastinal disease. Recognition of Castleman disease as the cause of renal amyloidosis and the understanding of CT and US findings of this entity are important for the management, as well as its diagnosis.

Adult↗