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Biomedical subjects

A N Leung

Publications and source records attributed to A N Leung.

7 recordsLinked to original sources
PubMed1996

Pulmonary tuberculosis: comparison of CT findings in HIV-seropositive and HIV-seronegative patients.

PURPOSE: To determine the differences in the computed tomographic (CT) appearance of pulmonary tuberculosis (TB) between patients with and patients without human immunodeficiency virus (HIV) infection. MATERIALS AND METHODS: CT scans and chest radiographs of 42 HIV-seropositive and 42 HIV-seronegative patients with pulmonary TB were reviewed. CD4 T-lymphocyte counts, measured in 40 seropositive patients, were at least 200 cells per microliter in 10 patients and were less that 200 cells per microliter in 30. RESULTS: Seropositive patients had a higher prevalence of lymphadenopathy at chest radiography (P< .05). The seropositive patients had a lower prevalence of consolidation (P< .05), cavitation (P< .01), and postprimary pattern (P< .05) at CT. HIV-seropositive patients had a higher frequency of miliary (P< .01) and extrapulmonary disease (P< .001). Similar features of pulmonary TB were observed in seropositive patients with mild and severe immunosuppression. CONCLUSION: HIV-seropositive patients had a lower prevalence of localized parenchymal disease and a higher prevalence of disseminated disease at CT.

AIDS-Related Opportunistic Infections↗
PubMed1996

Radiographic appearance of central venous catheters.

Central venous catheters (CVCs) are defined as venous access devices whose tips terminate in the superior or inferior vena cava, regardless of insertion site. CVCs allo reliable, painless, and repeated entry into the venous system and are commonly used for the administration of IV therapy, parenteral nutrition, and blood products as well as for the periodic blood sampling, hemodynamic monitoring, and hemodialysis. Catheter composition and design vary and depend on the duration of intended use and specific functions required. The purpose of this essay is to illustrate commonly used catheters, discuss factors governing catheter selection, and review important catheter-related complications.

Adult↗
PubMed1993

Parenchymal opacification in chronic infiltrative lung diseases: CT-pathologic correlation.

To correlate areas of parenchymal opacification on thin-section computed tomographic (CT) scans with histologic findings in patients with chronic infiltrative lung disease, the CT and histologic findings were evaluated in 29 patients with 11 such diseases. Open-lung biopsy was performed after CT. The area of predominant involvement was classified as air space, interstitium, or a mixture of both. A pathologic score of disease activity was assigned, and the extent of fibrosis was assessed whenever fibrosis was present. Parenchymal opacification on CT scans corresponded to abnormalities that affected mainly the air spaces in three patients (10%), the interstitium in 13 patients (45%), or both to a similar degree in 13 patients (45%). In 25 of 29 patients (86%), parenchymal opacification was associated with potentially treatable or reversible disease. Abnormalities considered irreversible were seen in three patients with end-stage fibrosis and one patient with talcosis. Parenchymal opacification on thin-section CT scans is a nonspecific finding in diseases that affect the air spaces, interstitium, or both but usually indicates potentially treatable or reversible disease.

Adult↗
PubMed1992

Primary tuberculosis in childhood: radiographic manifestations.

The aim of the study was to review the radiologic features of primary tuberculosis in childhood and to determine whether differences in patterns of disease occur among age and ethnic groups. Chest radiographs of 191 children with pediatric primary tuberculosis were reviewed by two observers. Lymphadenopathy, present in 92% of cases, was the most common abnormality identified on the initial chest radiograph and typically involved the hilar and paratracheal regions. Parenchymal abnormalities, identified in 70% of cases, occurred more commonly in the right lung (P less than .001). Children 0-3 years of age had a higher prevalence of lymphadenopathy (P less than .01) and a lower prevalence of parenchymal abnormalities (P less than .001) than older children. A lower prevalence of lymphadenopathy was found in whites than in nonwhites (P less than .02). The radiologic abnormalities often progressed in the initial follow-up. Lymphadenopathy, with or without concomitant parenchymal abnormality, is the radiologic hallmark of primary tuberculosis in childhood. However, distinct age-related and racial differences in presenting patterns of disease exist and should be recognized.

Age Factors↗
PubMed1991

Chronic diffuse infiltrative lung disease: comparison of diagnostic accuracy of high-resolution and conventional CT.

We compared the accuracies of high-resolution CT (HRCT) and conventional CT in determining the specific diagnoses in 75 consecutive patients with chronic diffuse infiltrative lung disease. Without knowledge of clinical or pathologic data, two reviewers independently assessed three separate sets of CT scans in random order: three HRCT scans, three 10-mm collimation CT scans obtained at the same levels as the HRCT scans, and a complete conventional CT scan. The HRCT scans were obtained at the level of the aortic arch, tracheal carina, and 1 cm above the right hemidiaphragm by using 1.5-mm collimation and a high spatial resolution algorithm. Observers gave the most likely diagnosis along with their degree of diagnostic confidence. The correct diagnosis, irrespective of confidence level, was reached with 71% of the HRCT scans and with 72% of both the corresponding 10-mm and complete conventional CT scans. Confidence level 1 (definite) was reached with 49% of HRCT scans, 31% of corresponding 10-mm scans, and 43% of complete conventional CT examinations; the correct diagnosis was made in 92%, 96%, and 94% of those examinations, respectively. In none of the patients were findings on the limited HRCT scan normal when findings on the conventional CT scan were abnormal. We conclude that in most patients with chronic infiltrative lung disease a specific diagnosis can be made by obtaining a limited number of HRCT scans.

Adult↗
PubMed1990

CT in differential diagnosis of diffuse pleural disease.

The CT features of benign and malignant pleural diseases have been described. However, the accuracy of these features in the differential diagnosis of diffuse pleural disease has not been assessed before. Without knowledge of clinical or pathologic data, we reviewed the CT findings in 74 consecutive patients with proved diffuse pleural disease (39 malignant and 35 benign). The patients included 53 men and 21 women 23-78 years old. Features that were helpful in distinguishing malignant from benign pleural disease were (1) circumferential pleural thickening, (2) nodular pleural thickening, (3) parietal pleural thickening greater than 1 cm, and (4) mediastinal pleural involvement. The specificities of these findings were 100%, 94%, 94%, and 88%, respectively. The sensitivities were 41%, 51%, 36%, and 56%, respectively. Twenty-eight of 39 malignant cases (sensitivity, 72%; specificity, 83%) were identified correctly by the presence of one or more of these criteria. Malignant mesothelioma (n = 11) could not be reliably differentiated from pleural metastases (n = 24). We conclude that CT is helpful in the differential diagnosis of diffuse pleural disease, particularly in differentiation of malignant from benign conditions.

Actinomycosis↗