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Biomedical subjects

K H Chang

Publications and source records attributed to K H Chang.

At least 163 records · Page 9Linked to original sources
PubMed1988

Computed tomography of cavernous sinus diseases.

We retrospectively analyzed CT scans of 21 cavernous sinus lesions in an attempt to discover CT findings helpful to the differential diagnosis. With the integration of various CT observations it was possible to categorize the lesions into inflammatory, vascular, benign neoplastic and malignant metastatic lesions with few exceptions. Four of 5 cases of septic cavernous sinus thrombophlebitis revealed unilateral or bilateral multiple irregular filling defects in the enhancing cavernous sinus with or without orbital inflammatory change. Four of 5 cases of carotid-cavernous fistula demonstrated unilateral or bilateral diffuse bulging and homogeneous enhancement of the cavernous sinus with obliteration of normal low densities of cranial nerves and gasserian ganglion. Dilatation and tortuosity of superior ophthalmic vein were also associated. Four of 5 cases of benign neoplastic lesion showed well-circumscribed enhancing masses confined to the cavernous sinus with pressure erosion or hyperostosis of adjacent bone. Five of 6 cases of malignant metastatic lesion showed changes suggesting malignancy such as destruction of adjacent bone or associated manifestations of intracranial spread. As compared with the axial scan, coronal scans proved to be more sensitive in detection of subtle cavernous sinus expansion, and superior in evaluation of intracavernous neural structures, relationships with the pituitary gland and changes in the skull base. Axial scans, however, were superior in detection of associated orbital and intracranial abnormalities. Scans in both projections are needed in the evaluation of most cavernous sinus diseases.

Arteriovenous Fistula↗
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

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↗
PubMed1987

PSK immunotherapy in cancer patients--a preliminary report.

A clinical trial was conducted by the Department of Radiation Oncology, Mackay Memorial Hospital, between 1981 and 1986, using PSK (Krestin) as an adjuvant immunotherapy to assess its potential benefit in cancer patients. The protocol called for a daily administration of 1 gram tid of PSK orally for at least a month upon completion of primary treatment for the tumor. A total of 67 patients were included in this study; 13 patients were excluded from evaluation because of noncompliance with the protocol. When three cases of toxicity were noted, PSK was discontinued for the three patients. Among the different groups of patients, nasopharyngeal carcinoma patients under PSK immunotherapy showed a significantly better survival when compared with historical controls (28% vs 17% five-year survival rate, p less than 0.05, generalized Wilcoxon test). It is therefore concluded that PSK can serve as an important adjunct in the treatment of nasopharyngeal carcinoma.

Adjuvants, Immunologic↗
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↗
PubMed1981

Leigh's subacute necrotizing encephalomyelopathy: possible diagnosis by CT scan.

A 28-month-old Korean girl developed a rapidly progressive disease, characterized by disturbance of consciousness, tremor, nystagmus, ophthalmoplegia, irregular deep respiration and vomiting. The patient succumbed 2 weeks after the onset of the illness. CT scan disclosed bilaterally symmetrical, low density lesions in the white matter and lateral basal ganglia. Distinctive histopathological findings at postmortem included spongiotic necrosis of the neuropil, marked capillary vascularity, persistence of relatively normal neurons in severely damaged zones, and comparatively little astrocytosis. The bilaterally symmetrical distribution of these changes in the putamen and periaqueductal gray matter of the midbrain were compatible with Leigh's disease.

Central Nervous System Diseases↗
PubMed1981

Hepatic, gut, and renal substrate flux rates in patients with hepatic cirrhosis.

The roles of liver, kidney, and gut in maintaining fuel homeostasis were studied in 28 patients with severe hepatic cirrhosis, 25 of whom had alcohol-induced cirrhosis. Hepatic, portal, and renal blood flow rates were measured and combined with substrate concentration differences across liver, gut, and kidney to calculate the net flux of free fatty acids, ketone bodies, triglycerides, and glucose with selected glucose precursors, including glycerol, lactate, pyruvate, and amino acids. Data from the catheterization studies were related to hepatic histology, glycogen content, and activities of gluconeogenic enzymes and compared with data obtained from control patients. The effects of food deprivation on net flux of fuels across the liver, gut, and kidney were assessed after overnight and after 3d of fasting. Activities of gluconeogenic enzymes were normal, but hepatic glycogen content was diminished in cirrhotic livers, probably as a consequence of extensive hepatic fibrosis. Extrahepatic splanchnic tissues (gut) had only a small influence on total splanchnic flux rates of carbohydrates, lipids and, amino acids. In cirrhotic patients, there was no mean renal glucose contribution to the bloodstream after an overnight or after a 3-d fast. After an overnight fast hepatic glucose production in patients with cirrhosis was diminished as a result of low-rate glycogenolysis. Hepatic gluconeogenesis and ketogenesis were increased. This pattern of hepatic metabolism mimics that seen in "normal" patients after more advanced stages of starvation. After 3 d of starvation, patients with hepatic cirrhosis have hepatic gluconeogenic and ketogenic profiles comparable to those of normal patients undergoing starvation of similar duration. Nevertheless, the total number of caloric equivalents derived from ketone bodies plus glucose corrected for recycled lactate and pyruvate added to the bloodstream by the cirrhotic livers that could be terminally oxidized by peripheral tissues was less than the contributions made by the normal livers, both after and overnight and after a 3-d fast.

Adult↗
PubMed1977

The mechanism of postshunt liver failure.

To determine the influence on postoperative hepatic mass, body weight, ammonia clearance, hepatic urea cycle enzyme activity, and hepatic protein metabolism, 59 dogs were divided into six experimental groups: sham operation end-to-side portacaval shunt, mesocaval shunt with subsequent end-to-side portacaval shunt, distal splenorenal shunt, caval left portal shunt, and portal venous seqregation with juglar vein interposition. Compared to total shunt, selective diversion of portal blood from the liver produces less postshunt liver atrophy, less body weight loss, improved maintenance of urea cycle enzyme activity, improved ammonia tolerance, and less decrease in hepatic deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein content. Segregation of left from right hepatic lobes, in relationship to portal or systemic venous hepatic perfusion or in relationship to gastroduodenopancreaticosplenic or intestinal portal venous drainage, caused little change in enzyme or protein metabolism in respective hepatic lobes.

Ammonia↗
PubMed1975

A scanning and transmission electron microscope study of the luminal coating on Dacron prostheses in the canine thoracic aorta.

The sequence of events occurring in a woven Dacron bypass in the canine thoracic aorta was followed from the first exposure to flowing blood for a period of 27 months. After 10 and 40 minutes exposure to flowing blood the surface was covered with masses of leukocytes, platelets, red cells, and some fibrin. By 24 and 48 hours most of the leukocytes had disappeared leaving the two end areas of the bypass covered with a thick film composed of red cells entrapped in a fibrin net. In the central portion of the bypass the Dacron fibers were covered by a rough film of particulate material and widely spaced clumps of platelets and occasional leukocytes connected by a few fibrin strands. AT 6 AND 7 DAYS THE SURFACE COVERING CONSISTED PRIMARILY OF RED CELLS AND FIBRIN. Between 2 and 8 weeks this was replaced by a matrix that was composed mostly of cells resembling fibroblasts or transition forms between these and smooth muscle cells. Some typical smooth muscle cells were observed in grafts 4 months or older. A sheet of flat cells had grown a few millimeters below the anastomoses at 7, 12, and 14 months. By 27 months the entire length of the graft had a patchy covering of endothelium. Only occasional isolated platelets were stuck to the exposed collagen. Thickening of the intraprosthetic lining was associated with infiltration of the cell-fiber matrix by masses of red cells. Thus it appears that under proper conditions of flow, thrombogenic surfaces such as Dacron and collagen are "conditioned" to become nonthrombogenic by the limited deposition of blood elements.

Animals↗
PubMedDate not supplied

MRI of CNS parasitic diseases.

This article reviews MRI findings of parasitic diseases of the central nervous system (CNS), with emphasis on neurocysticercosis, which is by far the most common CNS parasitic infection worldwide. MRI findings of neurocysticercosis are various, depending on the location (parenchymal, cisternal, ventricular, and spinal forms), and temporal evolutional stages (vesicular, colloid vesicular, granular nodular, and nodular calcified stages) of the worm. Classical findings of each location and stage are presented. Characteristic MRI findings of cerebral toxoplasmosis frequently seen in patients with acquired immunodeficiency syndrome (AIDS), paragonimiasis, and sparganosis that have most commonly been reported in East Asia are also illustrated. MRI is superior to CT scan in the evaluation of most CNS parasitic infections and is nearly diagnostic, particularly in endemic areas. Contrast-enhanced study is essential not only for specific diagnosis of the disease, but also for assessment of the inflammatory activity.

Amebiasis↗
PubMedDate not supplied

Nontraumatic prolapse of the orbital contents into the ethmoid sinus: evaluation with screening sinus CT.

PURPOSE: The purpose of this study is to evaluate the incidence and CT features of nontraumatic prolapse of the orbital content into the ethmoid sinus, which may be a cause of orbital complication of ethmoidectomy. MATERIALS AND METHODS: CT of 1,024 consecutive patients with subjective sinonasal symptoms who underwent screening sinus CT were reviewed and analyzed. The 573 men and 451 women were between the ages of 5 and 79 years old. The patients with a history of sinus surgery of facial trauma were excluded from this study. The incidence and CT features of dehiscence and/or bowing of the lamina papyracea with prolapse of the orbital content in each age group and differences between the age groups were analyzed. RESULTS: Ethmoidal prolapse of the orbital content was found in 67 patients (6.5%). There was a tendency of increasing incidence with increasing age. The incidence in the juvenile age group was significantly low (1.9%) as compared with that of adult. Four patients (0.4%) had bilateral lesions. Twenty-nine lesions showed prolapse of moderate to severe degree, and deformity of the medial rectus muscle on coronal CT image was associated in 21 lesions. Inflammatory change of adjacent ethmoid sinus was indicated in 19 lesions, and there was no statistical difference in incidence from that of the opposite side. CONCLUSIONS: The incidence of nontraumatic prolapse of the orbital content is far beyond general expectations, and detailed structural information with CT for this anatomic alteration may be important before endoscopic sinus surgery to avoid possible complication. The higher incidence in adult may suggest age-related acquired etiologic factors besides congenital dehiscence or weakness of the lamina papyracea.

Adolescent↗
PubMedDate not supplied

Effects of long-acting somatostatin analogue (Sandostatin) on manifest diabetic ketoacidosis.

Insulin deficiency and counterregulatory hormone excess are the basic process in the development of diabetic ketoacidosis (DKA). Somatostatin, which suppresses the secretion of glucagon and growth hormone, has been known to attenuate the rate of gluconeogesis and ketogenesis in insulin-dependent diabetes mellitus patients. However, the therapeutic efficacy of somatostatin has not been approved to be practical in the treatment of manifest DKA. To examine the additive effect of octreotide, the synthetic long-acting somatostatin analogue SMS 201-995, to conventional treatment of manifest DKA, we compared the correction time of acidosis, ketonuria, and hyperglycemia of patients treated with an intravenous infusion of low-dose insulin (4 units per hour) plus subcutaneous injection of octreotide (50 microg every 6 hours) by low-dose insulin alone. The correction time for hyperglycemia and acidosis did not show any difference between groups (p = 0.089, p = 0.82). However, the time for disappearance of ketonuria of the octreotide-treated group (38.0 +/- 32.0 h) was reduced significantly compared to other group (68.3 +/- 26.0 h) (p = 0.048). These results indicated that the addition of octreotide to conventional treatment of DKA might improve the correction of ketosis, but would not allow more rapid control of acidosis and hyperglycemia in manifest DKA.

Adolescent↗
PubMedDate not supplied

Malignant melanoma of the sinonasal cavity: explanation of magnetic resonance signal intensities with histopathologic characteristics.

PURPOSE: To evaluate the magnetic resonance (MR) findings of malignant melanoma of the sinonasal cavity and compare these findings with those of the histopathological examination. MATERIALS AND METHODS: The MR images of 11 patients with malignant melanoma of the sinonasal cavity were retrospectively reviewed. Ten patients had primary malignant melanoma of the sinonasal cavity and one had a local recurrence. The imaging findings were evaluated with special attention given to the signal intensity of the tumor, internal characteristics, and growth pattern on MR. Signal intensity and enhancement patterns of the tumors were compared with the histopathological findings. RESULTS: On T1-weighted image, 6 tumors were hyperintense (5 melanotic and one amelanotic melanoma), and 5 tumors were isointense or hypointense (4 amelanotic and one melanotic). On T2-weighted images, 2 amelanotic tumors showed hyperintensity, and 5 melanotic tumors showed hypointensity. Four tumors (one melanotic and 3 amelanotic) were isointense. Four of the 7 tumors with hyperintensity on T1-weighted images showed patchy, higher-signal intensity areas. In 3 of them, patchy areas of a higher degree of pigmentation were found on histopathological examination. There were multiple linear dark signal intensities on T2-weighted images and/or linear-enhancing areas on enhanced T1-weighted images within the masses in 5 of the 11 patients. These findings could be explained as intratumoral vessels in 4 tumors and fibrous septa in one tumor on histopathological examinations. CONCLUSION: Malignant melanoma of the sinonasal cavity shows characteristic MR signal intensity, which is mainly attributable to the degree and distribution of melanin pigmentation, and partly attributable to hemorrhage within the mass. The linear, low-signal intensity on T2-weighted images or enhanced lines are intratumoral vessels or fibrous septa.

Adult↗
PubMedDate not supplied

The clinical evaluations of pathophysiology for congenital middle ear cholesteatoma.

PURPOSE: Congenital middle ear cholesteatoma (CMEC) is less common than the acquired variety. Many theories have been put forward to explain the pathophysiology of CMEC; however, none of them have been convincingly proven thus far. This clinical study was performed to analyze the case reviews; assess the characteristic features of CMEC, and evaluate the correlation between those features and the pathophysiology of CMEC. METHODS: The medical records of patients who underwent otologic procedures at the hospitals of the Catholic University, Seoul, Korea, from January 1993 to November 1998 have been reviewed. RESULTS: Of the 14 patients, 3 had cystic lesions isolated to the anterosuperior quadrant of the mesotympanum. The lesions were easy to remove and did not affect the patients' hearing. Eleven patients had more extensive disease with posterior mesotympanum involvement; the lesions were large, were often too extensive to indicate a formative site, and caused ossicular damage. CONCLUSION: CMEC manifests in 2 distinctive forms according to the formation site. This distinctive formation site suggests that the pathophysiology of posterior lesions may be different from that of anterior ones. For early diagnosis of CMEC, a screening program should be established for children to prevent more extensive disease.

Adolescent↗