Biomedical subjects
Publications and source records attributed to J H Austin.
The CT findings of multiple lipid-containing dermal cysts in a patient with steatocystoma multiplex are presented. The characteristic locations, shapes, and densities of the cysts in this rare skin disorder are discussed.
Elastofibroma dorsi is a pseudotumorous connective tissue mass that characteristically arises between the chest wall and the inferior angle of the scapula. Its long axis is typically craniocaudal. Two patients are illustrated, each presenting with a fixed subscapular mass. Computed tomography showed each mass as elongated, incompletely marginated, and of soft tissue density deep to the inferior angle of a scapula. The latissimus dorsi and an underlying layer of fat were posterolaterally elevated inferior to the tip of the scapula. After incisional biopsy excluded sarcoma, each mass was locally excised.
A case of transdiaphragmatic empyema necessitatis due to tuberculosis presented clinically as a subcutaneous mass in the posteroinferior right chest. Imaging studies revealed a 12 cm diameter suprahepatic mass contiguous with thickened and calcified right pleura. Even in the preantibiotic era, such a presentation of empyema necessitatis was very unusual.
Computed tomography of a right middle lobe mass showed no evidence of calcification. Focal calcification in the right midhilar and subcarinal regions was presumed to be granulomatous. Thoracotomy revealed a partially psammomatous adenocarcinoma of lung and dense psammomatous deposits of adenocarcinoma in calcified regional lymph nodes.
OBJECTIVE: Our goal was to assess the diagnostic significance of calcification in carcinoma of the lung, as seen on CT. MATERIALS AND METHODS: We prospectively identified 500 consecutive patients with the provisional clinical diagnosis of lung cancer, who underwent CT examination of the chest from 1987 to 1991. Fifty-three (10.6%) of the 500 CT examinations revealed intratumoral calcification. When these 53 patients were reviewed retrospectively in 1992, CT examinations were available for 39, each with microscopic proof of primary carcinoma of the lung. Tumors were assessed for histologic subtype, size, and location and compared with a control group of the last 115 noncalcified, proven, primary carcinomas of the lung in the series. Intratumoral calcification seen on chest CT was assessed for location, extent, and pattern. RESULTS: The calcified tumors tended to be large (6.2 +/- 3.0 cm, mean diameter +/- SD) compared with the noncalcified tumors (4.4 +/- 2.3 cm) (p = 0.0001). The calcified tumors were central in 28 (72%) and peripheral in 11 (28%) patients. The noncalcified tumors were central in 52 (45%) and peripheral in 63 (55%) patients (p = 0.007). Punctate pattern of calcification correlated marginally with small cell carcinoma (p = 0.07). Histologic subtype showed no correlation with intratumoral location or extent of calcification. CONCLUSION: Calcification is identified in 10% of lung cancer, does not predict histologic subtype, and tends to occur in large, central tumors.
OBJECTIVE: Two CT techniques were compared in the assessment of mediastinal lymph nodes: 5 mm thick sections without intravenous contrast medium and 10 mm thick sections with intravenous contrast medium. MATERIALS AND METHODS: Seventy-nine adult patients were examined by chest CT. From the level of the aortic arch through the level of the right middle lobe bronchus 5 mm thick sections were performed without intravenous contrast medium, followed by 10 mm thick sections of the same region with intravenous contrast medium. Two chest radiologists separately reviewed each CT method for each patient. Mediastinal lymph nodes were localized according to the American Thoracic Society scheme. Lymph node diameter was measured on the short axis. RESULTS: The 5 mm thick noncontrast sections permitted identification of more mediastinal lymph nodes than the 10 mm thick contrast enhanced sections (p < 0.01, signed rank test). The 5 mm thick unenhanced sections tended to show slightly (1-2 mm) larger nodes than the 10 mm thick contrast enhanced sections (stations 7, 10R, both reviewers, p < 0.05, signed rank test). Nodes with a short axis diameter > or = 8 mm were identified comparably well using either CT technique. CONCLUSION: The present study indicates that CT of the mediastinum using 5 mm thick sections, without intravenous contrast medium, is an appropriate scanning technique for evaluation of mediastinal lymphadenopathy.
OBJECTIVE: Development of a general natural-language processor that identifies clinical information in narrative reports and maps that information into a structured representation containing clinical terms. DESIGN: The natural-language processor provides three phases of processing, all of which are driven by different knowledge sources. The first phase performs the parsing. It identifies the structure of the text through use of a grammar that defines semantic patterns and a target form. The second phase, regularization, standardizes the terms in the initial target structure via a compositional mapping of multi-word phrases. The third phase, encoding, maps the terms to a controlled vocabulary. Radiology is the test domain for the processor and the target structure is a formal model for representing clinical information in that domain. MEASUREMENTS: The impression sections of 230 radiology reports were encoded by the processor. Results of an automated query of the resultant database for the occurrences of four diseases were compared with the analysis of a panel of three physicians to determine recall and precision. RESULTS: Without training specific to the four diseases, recall and precision of the system (combined effect of the processor and query generator) were 70% and 87%. Training of the query component increased recall to 85% without changing precision.
Posteroanterior radiographs of the chest showed enlargement of vessels in the upper lung fields in 18 of 29 patients with interstitial lung diseases, despite normal pulmonary wedge pressures and normal or reduced pulmonary blood volumes. The degree of such redistribution ("diversion") did not correlate either with the severity of pulmonary hypertension observed at cardiac catheterization or with radiologic assessment of predominance of disease at the lung bases. Diversion did correlate with several indices of disease severity: reduction in vital capacity, reduction in diffusing capacity, reduction in pulmonary blood volume and radiographic severity of parenchymal abnormalities. Furthermore, diversion correlated with lung height, a variable which was not statistically related to the other indices of disease severity. Distension of upper lung vessels occurs in interstitial lung diseases as the result of a decreased hydrostatic gradient over which the lung is perfused (decreased lung height), partial obliteration of the vascular bed (decreased pulmonary volume), and, more speculatively, decreased extravascular pressure (increased lung recoil).
Large biopsy needles (18 and 19 gauge) have been reported to yield high-quality tissue cores for reliable histologic diagnosis. In our institution, image-directed percutaneous biopsy specimens obtained with these needles are processed routinely for simultaneous cytologic and histologic analysis. For the present study, we reviewed our experience with 82 such biopsies of the thoracoabdominal region. We examined the value of cytologic analysis as a supplement to histologic analysis of such biopsies in terms of diagnostic yield and sensitivity for detecting malignancy. Among the 82 specimens, material was adequate for histologic diagnoses in 70 (85%) and for cytologic diagnosis in 63 (77%). Combining the histologic and cytologic results increased the diagnostic yield to 93% (76 of 82 specimens). Forty-eight lesions were diagnosed as malignant by either one or both means of analysis. While histologic analysis produced 44 of the 48 positive results (92%), cytologic analysis produced 33 (66%) (P < .05, McNemar's test). Because tissue fragments were selected preferentially for histologic processing, histologic evaluation was more valuable than cytologic evaluation in achieving definitive diagnoses of malignancy. In spite of this bias in preparation technique, malignancy was diagnosed by cytologic analysis alone in 4 of the 48 positive cases (8%). We conclude that the combined approach of histologic and cytologic examination of large-gauge core needle biopsy specimens maximizes the diagnostic yield and sensitivity for detecting malignancy.