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Biomedical subjects

K M Yeon

Publications and source records attributed to K M Yeon.

At least 91 records · Page 5Linked to original sources
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

Menkes disease--an autopsy case with metal analysis of hair.

We report the first case of Menkes' disease in Korea, occurring in a 1 1/2 year old boy with characteristic clinical, arteriographic and pathologic features. Postmortem examination revealed widespread neuronal destruction and abnormally tortuous and elongated large arteries including cerebral, visceral and limb vessels. Microscopically, many of the hairs formed were twisted (pili torti), of varying caliber (monilethrix), and fractured (trichorrhexis nodosa). In the radioactivated analysis of scalp hair, copper elements was not found. The abnormal vessels were characterized by fragmentation and disruption of the internal elastic lamina with intimal proliferation. The neuronal destruction was widespread in the cerebral gray matter and in the cerebellum, and there was associated gliosis. The changes in the cerebellum were particularly severe, with neuronal loss in the internal granular cell layer. Many Purkinje cells were lost, and the remainder showed unusual dendritic sprouts from the cell body and grotesque proliferation of dendritic tree. In other organs, mild chronic peribronchitis, and scattered foci of immature glomeruli in renal cortex were noted.

Angiography↗
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↗
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

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↗
PubMedDate not supplied

Teratoid Wilms tumor in childhood: CT and ultrasonographic appearances.

Teratoid Wilms tumor is defined as an unusual variant of nephroblastoma, in which there is a significant diversity of cell types and tissues in a neoplasm, where areas of classic nephroblastoma tissue are also present. We report a case of teratoid Wilms tumor demonstrated as a unilateral cystic and solid renal mass containing fatty tissue on ultrasonography and computed tomography.

Child, Preschool↗
PubMedDate not supplied

Hepatic hemangioma: contrast-enhancement pattern during the arterial and portal venous phases of spiral CT.

The objective of the present study was to evaluate contrast-enhancement patterns of hepatic hemangioma according to size during hepatic arterial (30-s delay) and portal venous (65-s delay) phases of spiral computed tomography (CT). During a 10-month-period, 73 patients with 118 hemangiomas underwent two-phase spiral CT examination. The enhancement patterns of tumors were divided into four types based on the attenuation of surrounding liver parenchyma: peripherally nodular high, uniform high, iso, and low. The diameter of the tumors were <10 mm (n = 39), 11-20 mm (n = 33), and >21 mm (n = 46). Overall, the most common enhancement patterns of hemangioma were peripherally nodular high (66/118, 55. 9%) during the arterial and portal venous phases. The second most common contrast-enhancement patterns of hemangioma were uniform high (15/118, 12.7%) during the arterial and portal venous phases. In tumors smaller than 20 mm, 11 (9.3%) had low-low attenuation and two (1.7%) had iso-low attenuation during the arterial and portal venous phases, respectively. In conclusion, at two-phase spiral CT, the most common contrast-enhancement patterns of hemangioma are peripherally nodular high and/or uniform high during the arterial and portal venous phases. However, hemangiomas smaller than 2 cm may have atypical enhancing patterns including low and iso-attenuation.

Adult↗
PubMedDate not supplied

Heterotopic pancreas of the stomach: CT findings correlated with pathologic findings in six patients.

BACKGROUND: The purpose of this study was to characterize the computed tomographic (CT) findings of heterotopic pancreas of the stomach. METHODS: CT scans of six surgically proven cases of heterotopic pancreas of the stomach were reviewed. Three were dynamic spiral CT scans, with both arterial dominant and late phase scans. In other three, both unenhanced and contrast-enhanced scans were obtained by using conventional techniques. Particular attention was given to the enhancement of the heterotopic pancreas. Pathologic and surgical findings were correlated with CT findings. RESULTS: The locations were in the gastric antrum in five cases and in the mid-body in one. Size ranged from 1 cm to 3 cm (mean = 2.1 cm). Three cases showed homogeneous, strong enhancement similar to the pancreas and consisted mainly of pancreatic acini with the same histologic features as the normal pancreas. Two cases showed poor enhancement and consisted mainly of ducts and hypertrophied muscle; pancreatic acini were a minor component. In one case appearing as a cystic lesion on CT, a pseudocyst was found with many ducts and some nests of pancreatic acini. CONCLUSIONS: Heterotopic pancreas of the stomach showed a diverse spectrum of CT findings. Good understanding of these CT findings may be helpful in making a correct diagnosis.

Adolescent↗
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

Renal artery evaluation: comparison of spiral CT angiography to intra-arterial DSA.

PURPOSE: To assess the role of spiral computed tomographic angiography (CTA) in renal artery evaluation. MATERIALS AND METHODS: The authors prospectively performed both CTA and intraarterial digital subtraction angiography (IA-DSA) in 50 consecutive patients (24 males and 26 females) who ranged between 9 and 77 years old (mean, 39.3 years), in whom renovascular hypertension was suspected (n = 32) or who were potential renal donors (n = 18). The major scan parameters of CTA were 3-mm collimation, 4-5-mm/sec table speed, and 2-mm reconstruction interval. Both CTA and IA-DSA images were blindly interpreted by two radiologists with respect to the number of accessory renal arteries and the location and severity of renal artery stenosis. RESULTS: CTA demonstrated 27 of 28 accessory renal arteries (detection rate = 96%). For the detection of stenoses greater than 50% (37 of 127 renal arteries, at 40 sites), the sensitivity and specificity of CTA were 90% and 97%, respectively. For the detection of stenoses greater than 50% in the main renal arteries (32 of 99 main renal arteries, at 32 sites), the sensitivity and specificity of CTA were 100% and 97%, respectively. CONCLUSION: CTA is a reliable and accurate screening modality for the evaluation of renal arteries in patients with suspected renovascular hypertension and in potential renal donors.

Adolescent↗
PubMedDate not supplied

CT findings of lobar bronchioloalveolar carcinoma.

The CT findings in a case of lobar bronchioloalveolar carcinoma included stretching, spreading, and uniform narrowing of the involved bronchi without obstruction.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMedDate not supplied

Hepatic choriocarcinoma in a neonate: MR appearance.

We present the MR findings of hepatic choriocarcinoma in a 2-week-old infant. Two masses of heterogeneous signal intensity were evident; one was an extensive mass on the left side of the liver and the other was a "daughter" nodule in the right lobe. Peripheral portions of the masses were hyperintense on T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) suggesting subacute hemorrhage. Central portions of the masses were hypointense on T1WI and bright on T2WI. T1-weighted postgadolinium imaging showed peripheral enhancement of both tumor nodules. The infant's mother had normal serum beta-human chorionic gonadotropin levels and pelvic CT.

Biomarkers, Tumor↗
PubMedDate not supplied

Mediastinal Castleman disease: CT findings.

OBJECTIVE: Our objective was to characterize the CT findings of mediastinal Castleman disease. MATERIALS AND METHODS: We reviewed the CT findings of mediastinal Castleman disease in 10 patients. RESULTS: In nine cases of hyaline-vascular type Castleman disease, lymph nodes were 2-7 cm in diameter and located in the hilum in six patients, superior mediastinum in two patients, and posterior mediastinum in one patient. On CT the tumors were well-demarcated round masses showing dense homogeneous enhancement after contrast medium injection. Dynamic CT in one case showed gradual centripetal enhancement of the mass. In one case of hyaline-vascular type Castleman disease, lumpy and irregular calcifications were noted in the center of the mass. In the one case of plasma cell type Castleman disease, multiple small homogeneously enhancing nodes were found in the mediastinal and supraclavicular area. CONCLUSION: CT findings may suggest the preoperative diagnosis of mediastinal Castleman disease.

Adolescent↗
PubMedDate not supplied

Complications of Klebsiella pneumonia: CT evaluation.

OBJECTIVE: To evaluate the CT features of complicated Klebsiella pneumonia. MATERIALS AND METHODS: We retrospectively reviewed 15 CT examinations from 11 consecutive patients with complicated Klebsiella pneumonia with special attention to internal architecture of pneumonic consolidation and its changes on follow-up CT. On plain radiography, abscess or cavitation was suspected in all patients. The diagnosis was established by isolation of Klebsiella pneumoniae from blood in six patients, from sputum in two, and from both in three. Five patients underwent follow-up CT due to progression (one) or incomplete resolution (four) of the disease despite antimicrobial therapy. RESULTS: In all patients pneumonic consolidation was composed of two intermingled components: enhancing homogeneous areas and poorly marginated low-density areas with multiple small air cavities, suggesting necrotizing pneumonia. In nine patients scattered enhancing structures probably due to atelectatic lung and pulmonary vessels were noted within necrotic areas of consolidated lung. In eight patients pleural complications such as effusion (all) or diffuse pleural enhancement (five) were seen. In two patients with multilobar disease and delayed treatment, multiple small abscess cavities coalesced to form a large cavity with sloughing of lung tissue, suggesting pulmonary gangrene and lung abscess formation on 18 and 45 day follow-up CT, respectively. In three other patients necrotizing pneumonia resolved slowly from the periphery to the center with residual fibrosis on follow-up CT at 2-3 months. CONCLUSION: The most common CT manifestation of complicated Klebsiella pneumonia was necrotizing pneumonia associated with pleural abnormalities. In extensive cases, pulmonary gangrene or lung abscess was a rare complication.

Adult↗
PubMedDate not supplied

Primary adenoid cystic carcinoma of the cervical trachea mimicking thyroid tumor: CT evaluation.

OBJECTIVE: Our goal was to describe the CT characteristics of adenoid cystic carcinomas of the trachea mimicking thyroid tumors. MATERIALS AND METHODS: Computed tomography of four patients with pathologically proved adenoid cystic carcinomas extending into the thyroid gland was retrospectively reviewed. One case was also examined with MR. RESULTS: The masses encircling the trachea and circumferential thickening of the tracheal wall were demonstrated in all four cases. The longitudinal extent of the tracheal wall thickening was also demonstrated in all cases. The tumors had a broad base on the trachea and convex margin on the thyroid gland. They were all homogeneous, generally smoothly marginated, and isoattenuating on postcontrast CT scans. CONCLUSION: Adenoid cystic carcinomas were usually seen on CT scans as homogeneous masses encircling the posterolateral trachea with thickening of the tracheal wall in the transverse and longitudinal planes. These CT characteristics may be helpful in the differential diagnosis of adenoid cystic carcinomas mimicking thyroid tumors.

Adult↗
PubMedDate not supplied

CT and US findings of pancreatoblastoma.

PURPOSE: Our goal was to evaluate US and CT findings of pancreatoblastoma. METHOD: Three US and four CT scans before surgery and one follow-up CT after surgery were reviewed in four patients (two female, two male) with pathologically proven pancreatoblastoma. The mean age of the patients was 4 years (range 2-5 years). The masses were analyzed for origin, US and CT architecture, presence of calcification, enhancement pattern, and metastatic spread. RESULTS: In two patients, the tumors arose from the pancreatic head and in one patient from the pancreatic tail. The mean largest diameter of the masses was 10 cm, ranging from 5 to 14 cm. Sonography obtained from three cases showed mixed echogenic solid mass. On the CT scan, all tumors were huge, lobulated masses with heterogeneous attenuation. One tumor contained numerous foci of calcification. On the enhanced CT scan, three tumors showed multiloculated appearance by enhancing internal septations. There was no evidence of metastasis to distant organ or abdominal lymph node in any case. CONCLUSION: We suggest that the most common US finding of pancreatoblastoma is a mixed echogenic, solid mass inseparable from the pancreas, and the most common CT finding is a relatively well defined, lobulated, huge mass with multiloculated appearance by enhancing septae in or near the lesser sac.

Child, Preschool↗
PubMedDate not supplied

Lung cancer in patients with idiopathic pulmonary fibrosis: CT findings.

PURPOSE: The frequency of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is higher than that of general population. To evaluate CT findings of lung cancer associated with IPF, we analyzed 32 patients with lung cancer associated with IPF. METHOD: We analyzed retrospectively 32 patients with histologically confirmed lung cancer out of 244 consecutive cases diagnosed as IPF by either CT and clinical findings (n = 220) or histologically (n = 24). The patients were 40-85 years old (mean 66 years, M/F = 31/1). Scanning techniques were conventional CT in 24 patients, high-resolution CT (HRCT) in 2 patients, and both conventional CT and HRCT in 6 patients. We analyzed the CT patterns, locations, and histologic types of lung cancer. RESULTS: The frequency of lung cancer in patients with IPF was 13.1% (32/244). In 17 of 32 patients, the CT findings of lung cancer were ill defined lesions mimicking air-space consolidation. Lung cancer was located mainly in the lower lobes (21/32) and peripheral portion (21/32). Histologically, squamous cell carcinoma was the most common type (18/32). CONCLUSION: Typical CT findings of lung cancer were ill defined consolidation-like masses at the peripheral portion where the most advanced fibrosis was located.

Adenocarcinoma↗