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Biomedical subjects

W K Moon

Publications and source records attributed to W K Moon.

50 records · Page 3Linked to original sources
PubMed1992

Calcified bladder tumors. CT features.

CT scans of the pelvis in 132 patients with bladder tumor were reviewed. Calcifications in the bladder tumor were found in 11 men (8%) including transitional cell carcinoma (n = 6), mucinous adenocarcinoma (n = 4), and malignant mixed mesodermal tumor (n = 1). Calcifications in transitional cell carcinoma were located on the surface of the tumor in all 6 cases: they were nodular in 4 cases, nodular and arched in one, and plaque-like massive calcification in one. In mucinous adenocarcinoma multiple fine punctate calcifications were scattered within the mass in all 4 cases. The CT appearance of calcifications in bladder tumors may be helpful in predicting the histologic type of the tumor.

Adenocarcinoma, Mucinous↗
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

Iodized-oil retention within hepatic hemangioma: characteristics on iodized-oil CT.

OBJECTIVE: The purpose of this study was to describe the characteristic computed tomographic (CT) appearance of iodized-oil retention in hepatic hemangioma and to evaluate the duration of the retention of iodized oil on follow-up CT. METHODS: Seventeen hepatic hemangiomas of 14 patients were studied with CT performed 1-3 weeks after injection of 2-9 ml of iodized oil (iodized-oil CT) for the characterization of focal hepatic lesions, which needed differential diagnosis with hepatocellular carcinoma in 10 patients, for therapy in two patients, and for chemoembolization therapy of accompanying hepatocellular carcinomas in two. Twelve patients had 1-7 follow-up CT scans within an interval of 1-38 months. RESULTS: In all cases, iodized-oil CT showed iodized-oil retention within the tumor, regardless of tumor size, shape, location, and amount of injected iodized oil. The distribution was incomplete and predominantly peripheral in all cases. Central retention was also seen in seven cases, in which a relatively large amount of iodized oil was injected, but retention of iodized oil in the tumor was incomplete even in two cases in which a large amount of iodized oil was injected to relieve symptoms and in three cases in which prominent uptake of surrounding liver parenchyma was seen. Patterns of retention were predominantly spotty in five, predominantly nodular in four, and mixed in eight patients. Retention materials slowly washed out but persisted for at least 3 months and up to 38 months (mean = 18.1 months), and complete washout was not seen in any cases at follow-up CT. CONCLUSION: In all cases of hepatic hemangiomas, iodized oil was retained, and retention persisted over several months. Distribution and patterns of retention were characteristically peripheral, spotty, and nodular at iodized-oil CT. Knowledge of the iodized-oil CT appearance of hepatic hemangioma would be helpful to interpret follow-up CT studies of patients who have undergone iodized-oil chemoembolization procedures.

Adult↗
PubMedDate not supplied

Paraffinoma in the urinary bladder: CT findings.

A case of a paraffinoma in the urinary bladder is presented. Plain radiography and intravenous urography showed a low attenuation filling defect in the urinary bladder, and CT demonstrated a lobulated fat-attenuation mass floating in the urinary bladder.

Adult↗
PubMedDate not supplied

Malignant schwannomas of the thorax: CT findings.

We reviewed CT of eight patients with malignant schwannomas arising in the thorax. Only one patient had neurofibromatosis. Five lesions occurred in the posterior mediastinum, one lesion was in the middle mediastinum, and two lesions were in the chest wall. Common CT findings were the presence of low-density areas (six of eight), compression of adjacent structures (six of eight), pleural abnormalities (six of eight), such as pleural effusion or pleural nodules, and metastatic pulmonary nodules (five of eight). Pleural abnormalities or pulmonary nodules were detected in seven of eight patients. These CT findings can help in differentiating malignant schwannoma from benign neurogenic tumor.

Adult↗
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

CT and MR imaging of head and neck tuberculosis.

Tuberculosis of the head and neck can involve the cervical lymph nodes, larynx, temporal bone, sinonasal cavity, eye, pharynx, thyroid gland, and skull base. Although computed tomography (CT) and magnetic resonance (MR) imaging can accurately demonstrate the sites, pattern, and extent of the disease, both modalities have limitations in the evaluation of head and neck tuberculosis. Imaging and clinical features of head and neck tuberculosis are often varied and nonspecific and frequently mistaken for those of carcinoma. However, tuberculous lymphadenitis is often characterized by areas of low attenuation or low signal intensity with rim enhancement or calcification, and laryngeal tuberculosis usually manifests as a diffuse bilateral lesion with or without a focal mass. A thorough knowledge of head and neck tuberculosis is important because early diagnosis and therapy may prevent a permanent loss of function or needless surgery.

Adolescent↗