Kyung Soo Lee

About 5% of T1 non-small cell lung cancers (ie, lung cancers less than 3 cm in diameter), mostly focal nodular bronchioloalveolar carcinomas and carcinoid tumors, demonstrate no uptake at fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and appear to be indolent in growth; consequently, they are associated with long-term patient survival. About 21% of T1 lung cancers show mediastinal nodal metastasis at the time of diagnosis and about 24% show extrathoracic metastasis, mostly brain metastasis, either at the time of diagnosis or at 1-year follow-up. T1 lung cancers with a large ground-glass attenuation component (50% of tumor volume) at thin-section computed tomography (CT) have a good prognosis with less likelihood of mediastinal nodal or extrathoracic metastasis. On the other hand, solid cancer lesions, especially those with a spiculated margin or with bronchovascular bundle thickening in the surrounding lung, more frequently demonstrate local vessel invasion, lymph node metastasis, and extrathoracic metastasis. In these tumors, work-up for extrathoracic metastases (including whole-body FDG PET or brain magnetic resonance imaging and mediastinoscopy for mediastinal nodes) may be needed, even when CT demonstrates no enlarged nodes in the mediastinum.

PURPOSE: To identify and describe the thin-section computed tomographic (CT) findings of nontuberculous mycobacterial (NTM) pulmonary infection in immunocompetent patients and to compare these findings with histopathologic findings. MATERIALS AND METHODS: Between April 2002 and March 2003, the thin-section chest CT findings in and histopathologic lung tissue specimens from 22 patients who fulfilled the American Thoracic Society diagnostic criteria for NTM pulmonary infection were retrospectively reviewed. The lung lesion patterns (ie, small nodules, branching centrilobular nodules [ie, tree-in-bud pattern], consolidation, cavities, bronchiectasis, and volume loss) seen at CT at the sites of transbronchial lung biopsy (n = 22) or lobectomy (n = 1) were compared with the histopathologic findings. RESULTS: Thirteen of the 22 patients were found to have Mycobacterium abscessus pulmonary infection; seven, to have Mycobacterium avium-intracellulare complex infection; and two, to have Mycobacterium fortuitum inf...

Objective: The purpose of this study was to determine the optimal slab thickness for condensing transaxial images into maximum intensity projection (MIP) images in the evaluation of small pulmonary arteries using 16-slice multidetector-row computed tomography (MDCT). Methods: Helical computed tomography (CT) scans were obtained from lung apices to bases using 16-slice MDCT [120 kV(peak), 180 mA, beam width of 10 mm, beam pitch of 1.375, and reconstruction thickness of 1.25 mm] in 29 patients suspected of having a pulmonary embolism. Four kinds of image series (1.25-mm thick original transaxial source images and 3 kinds of reconstructed images using the MIP technique with slab thicknesses of 2.5 mm, 5 mm, and 10 mm) were obtained from each patient and forwarded to monitors of a picture archiving and communication system for analysis by 2 independent observers. The observers recorded the name of the segmental (20 total; 10 in each lung) and subsegmental (40 total; 20 in each lung) arteries that were traceable in each image series. Image quality of the 4 image types were graded into 5 scales based on their degree of vascular opacification, the sharpness of the vascular margins of the contrast-enhanced CT angiograms, and the visibility of lung parenchyma (excellent [5] to nondiagnostic [1]) and compared. Results: In both the 1.25-mm thick original transaxial and 2.5-mm thick MIP images, a higher percentage of subsegmental arteries was traceable (91.3% [2119/2320 observations] and 87.2% [2023/2320 observations], respectively; P P < 0.0001). No statistically significant difference was found between the scores of the image quality of the 1.25-mm thick original transaxial images and the 2.5-mm thick MIP images. Conclusion: After reducing the image number by one half, 2.5-mm thick MIP images using 16-slice MDCT are found to provide satisfactory images, which are comparable to 1.25-mm thick transaxial images for the analysis of subsegmental pulmonary arteries in patients suspected of pulmonary embolism.

Along with clinical examination and laboratory tests, imaging plays a key role in the diagnosis of pulmonary embolism. Multi–detector row helical computed tomography (CT) is particularly helpful in the diagnosis of acute pulmonary thromboembolism (PTE) owing to its capacity to directly show emboli as intravascular filling defects. Although parenchymal abnormalities at CT are nonspecific for acute PTE, they may contribute to a correct diagnosis of chronic PTE, the characteristic helical CT features of which are similar to its angiographic features and include webs or bands, intimal irregularities, abrupt narrowing or complete obstruction of the pulmonary arteries, and “pouching defect.” Nonthrombotic pulmonary embolism is an uncommon condition but is sometimes associated with specific imaging findings, including discrete nodules with cavitation (septic embolism), widespread homogeneous and heterogeneous areas of increased opacity or attenuation that typically appear 12–24 hours after trauma (fat embolism),...

Thymic epithelial tumor is a distinctive pathologic entity exhibiting variable histologic features and heterogeneous oncologic behavior. Among the various classification systems, that of the World Health Organization has been adopted because of good correlation between histologic appearance and oncologic behavior. Radiologically, a smooth contour and round shape are most suggestive of a type-A tumor, whereas an irregular contour most strongly suggests type C. Pleural seeding is rare in type-A and AB tumors; calcification is suggestive of type B. Type-C tumors are significantly larger and more commonly associated with lymphadenopathy than type B3. At T2-weighted MR imaging, lobular internal architecture is more prominent in types B1, B2, and B3 tumors than in others. However, imaging findings among the various types overlap to some extent, and the ability of imaging studies to differentiate types AB, B1, B2, and B3 is limited.