Computed tomography of inflation-fixed lungs: the beaded septum sign of pulmonary metastases

Differential diagnosis of pulmonary sarcoidosis: a review

Diagnosing pulmonary sarcoidosis raises challenges due to both the absence of a specific diagnostic criterion and the varied presentations capable of mimicking many other conditions. The aim of this review is to help non-sarcoidosis experts establish optimal differential-diagnosis strategies tailored to each situation. Alternative granulomatous diseases that must be ruled out include infections (notably tuberculosis, nontuberculous mycobacterial infections, and histoplasmosis), chronic beryllium disease, hypersensitivity pneumonitis, granulomatous talcosis, drug-induced granulomatosis (notably due to TNF-a antagonists, immune checkpoint inhibitors, targeted therapies, and interferons), immune deficiencies, genetic disorders (Blau syndrome), Crohn's disease, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, and malignancy-associated granulomatosis. Ruling out lymphoproliferative disorders may also be very challenging before obtaining typical biopsy specimen. The first step is an assessment of epidemiological factors, notably the incidence of sarcoidosis and of alternative diagnoses; exposure to risk factors (e.g., infectious, occupational, and environmental agents); and exposure to drugs taken for therapeutic or recreational purposes. The clinical history, physical examination and, above all, chest computed tomography indicate which differential diagnoses are most likely, thereby guiding the choice of subsequent investigations (e.g., microbiological investigations, lymphocyte proliferation tests with metals, autoantibody assays, and genetic tests). The goal is to rule out all diagnoses other than sarcoidosis that are consistent with the clinical situation. Chest computed tomography findings, from common to rare and from typical to atypical, are described for sarcoidosis and the alternatives. The pathology of granulomas and associated lesions is discussed and diagnostically helpful stains specified. In some patients, the definite diagnosis may require the continuous gathering of information during follow-up. Diseases that often closely mimic sarcoidosis include chronic beryllium disease and drug-induced granulomatosis. Tuberculosis rarely resembles sarcoidosis but is a leading differential diagnosis in regions of high tuberculosis endemicity.

Interstitial Lung Disease after Pleurodesis for Malignant Pleural Effusion

Objective Pleurodesis is an effective therapy for malignant pleural effusion (MPE). While interstitial lung disease (ILD) has been regarded as a serious complication of pleurodesis, its clinicopathological characteristics have not been fully understood. This study was conducted to elucidate the incidence of ILD and the risk factors for ILD in patients who underwent pleurodesis to control MPE. Methods The medical records of patients who underwent pleurodesis in Aichi Medical University between March 2008 and February 2013, the period before the approval of talc in Japan, were retrospectively analyzed. Results A total of 84 patients underwent pleurodesis, all using OK-432. ILD occurred in 13 patients (15.5%). The development of ILD after pleurodesis was significantly associated with old age (odds ratio [OR]: 4.82, 95% confidence interval [CI]: 1.22-19.08) and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment (OR: 5.97, CI: 1.7-20.9). A multivariate analysis revealed that >67 years of age (p=0.01) and EGFR-TKI treatment (p=0.02) were significantly associated with the development of pleurodesis-related ILD. Among the patients who received both pleurodesis and EGFR-TKIs (n=23), 8 patients developed ILD. All of these patients were receiving EGFR-TKI therapy at the time of pleurodesis or within 30 days after pleurodesis. In contrast, no cases of ILD were observed among the patients who stopped EGFR-TKIs before pleurodesis or started EGFR-TKIs at more than 30 days after pleurodesis. Conclusion ILD seemed to be a frequent complication of pleurodesis in patients using OK-432, especially elderly patients and those who underwent pleurodesis while receiving EGFR-TKI therapy or who started EGFR-TKI therapy within 30 days after pleurodesis.

Hematogeneous Pulmonary Metastasis

The purpose of this study was to develop an experimental model of pulmonary metastases using VX-2 tumor, and to describe sequential radiologic and pathologic findings with special attention to the interstitial changes around the metastatic nodules. Through ear veins of 25 rabbits, VX-2 tumor cell suspension was injected with 0.8-mm scalp needles. Chest radiographs were taken every other day after tumor injection. The rabbits were sacrificed at scheduled times from 3 to 30 days after tumor injection. The inflated and fixed lungs were examined with visual inspection, low-kV radiography, high resolution CT (HRCT), microradiography of the sliced lung and with histopathologic studies. Hematogeneous pulmonary metastases occurred in 24 of 25 rabbits. In addition to the metastatic nodules, perinodular and peribronchovascular infiltrations were seen on low-kV radiography, HRCT, microradiography and histologic studies.

[Surgery of lung metastases]

The aim of surgical treatment of lung metastases is to eliminate all known tumoral disease. After a clinical diagnosis of lung metastases, the criteria for selecting patients who are candidates for surgical treatment, the route of access to the thoracic cavity and the technique for metastases resection are not universally defined. Moreover, half of all patients will show recurrence and the advisability of further surgery will have to be reconsidered. The present article discusses aspects related to the oncological and functional limits of surgical resection of lung metastases, preoperative workup, postoperative follow-up, and the surgical approaches and resection techniques.

Illustrated Brazilian consensus of terms and fundamental patterns in chest CT scans

The objective of this new Brazilian consensus is to update and to continue the standardization of the principal terms and fundamental patterns in chest CT scans in Portuguese. There is a succinct definition of the principal terms used to describe chest CT findings, as well as illustrations of classic examples. The group of authors comprised radiologists specializing in chest radiology and holding membership in the Brazilian College of Radiology and Diagnostic Imaging, as well as pulmonologists having a special interest in diagnostic imaging and holding membership in the Brazilian Thoracic Association.

[HRCT of the lung: nodular pattern: anatomy and differential diagnosis]

Since the spectrum of differential diagnoses is wide, the interpretation of a nodular pattern in lung lesions detected on CT is a frequent problem. Number, size, localization, and morphology (shape, density, margins) contribute to evaluating the most probable differential diagnosis. "Classical" high resolution CT or high resolution image reconstructions from multiple row detector CT helical acquisitions achieve a detail resolution that makes it possible to distinguish findings by their typical predominance in certain anatomical compartments of the lung. The position of bronchial, vascular and lymphatic structures can be determined down to the secondary pulmonary lobule, the smallest subunit of the lung to be separated by septa of connective tissue. Based on this, a centrilobular predominance of nodules, i.e. with a tree-in-bud pattern, is a frequent sign of bronchiolitis. Perilymphatic predominance in the periphery of the lobules is associated with sarcoidosis or lymphangitic spread of cancer. Random distribution of nodules is interpreted as a sign of hematogenic spread of disease. Hence the subtle interpretation of specific findings on HRCT can contribute substantially to clinical decision making, although these signs may not always replace biopsy and histologic workup.

Fatal cor pulmonale caused by pulmonary tumor microembolism in a patient with occult gastric cancer

BACKGROUND

A fatal pulmonary tumor microembolism is rarely caused by an occult gastric cancer.

METHODS AND RESULTS

We report the case of a 40-year-old woman who died after 3 days of progressive dyspnea, cough, and pulmonary hypertension. Postmortem examination demonstrated the presence of an occult diffuse-type gastric carcinoma, which had caused emboli in about 80% of small pulmonary arteries and arterioles. Despite an interatrial defect in the fossa ovalis, no parenchymal metastases were documented.

CONCLUSION

Pulmonary tumor microembolism may be suspected in patients complaining of unexplained progressive dyspnea and who develop acute or subacute cor pulmonale.

Thin-section CT of the secondary pulmonary lobule: anatomy and the image--the 2004 Fleischner lecture

The secondary pulmonary lobule is a fundamental unit of lung structure, and it reproduces the lung in miniature. Airways, pulmonary arteries, veins, lymphatics, and the lung interstitium are all represented at the level of the secondary lobule. Several of these components of the secondary lobule are normally visible on thin-section computed tomographic (CT) scans of the lung. The recognition of lung abnormalities relative to the structures of the secondary lobule is fundamental to the interpretation of thin-section CT scans. Pathologic alterations in secondary lobular anatomy visible on thin-section CT scans include interlobular septal thickening and diseases with peripheral lobular distribution, centrilobular abnormalities, and panlobular abnormalities. The differential diagnosis of lobular abnormalities is based on comparisons between lobular anatomy and lung pathology.

Fluorodeoxyglucose positron emission tomography pattern of pulmonary lymphangitic carcinomatosis

OBJECTIVE

The purpose of this study was to evaluate the F-fluorodeoxyglucose (FDG) positron emission tomography (PET) uptake in pulmonary lymphangitic carcinomatosis identified on computed tomography (CT) in patients with lung cancer.

METHODS

This was a retrospective analysis of F-FDG PET images in 7 patients (4 male and 3 female, mean age: 56.6 +/- 6.6 years) with lung cancer with a CT-based diagnosis of lymphangitic carcinomatosis. The F-FDG PET scans in a group of 7 patients (4 male and 3 female, mean age: 42.1 +/- 5.66 years) with normal chest CT scans served as a control group. Mean standardized uptake values (SUVs) were calculated based on average tumor uptake, initial injected activity, and body weight.

RESULTS

The intensity of F-FDG uptake in diseased lung is significantly greater than in corresponding normal contralateral lung or in the lungs of normal controls (P = 0.003). The ratio of the SUV of lung with lymphangitic carcinomatosis to corresponding contralateral normal lung was significantly increased (P = 0.006), and the ratio of the SUV of mediastinal blood pool to lung with lymphangitic carcinomatosis was significantly decreased (P = 0.0002).

CONCLUSION

There is diffuse increased FDG uptake in the lung corresponding to the CT pattern of lymphangitic carcinomatosis.

Diseases affecting the peribronchovascular interstitium: CT findings and pathologic correlation

Central bronchi and pulmonary arteries are surrounded and enveloped by a strong connective-tissue sheath termed the peribronchovascular interstitium, extending from the level of the pulmonary hila into the peripheral lung. Thickening of the peribronchovascular interstitium can be seen in a wide variety of diseases. The CT appearance can be smooth, nodular, or irregular depending on the underlying cause. Many of the diseases affecting the peribronchovascular interstitium are entities that show a predilection for lymphatic routes, such as sarcoidosis, pulmonary lymphangitic carcinomatosis, silicosis, and lymphoproliferative disorders. There are other entities that mainly affect the peribronchovascular interstitium without a predominant perilymphatic distribution, such as hydrostatic pulmonary edema, cryptogenic organizing pneumonia, Kaposi's sarcoma, interstitial pulmonary emphysema, and interstitial hemorrhage. Although there is an overlap in radiologic features, some CT findings are useful in differentiating among these entities. When CT shows mainly peribronchovascular abnormality, the differential diagnosis is considerably reduced, and it is generally possible to reach the correct diagnosis by considering the clinical context. We illustrate the CT findings and pathologic correlation for a number of different disorders that mainly affect the peribronchovascular interstitium.

Imaging of Metastatic Disease to the Thorax

Tumor imaging is at the forefront of radiology technology and is the focus of most cutting edge research. Radiologic applications for imaging of metastases are applied to initial staging, restaging after neoadjuvant therapy, and follow-up surveillance after therapy for tumor recurrence. CT is the routine imaging choice in staging, restaging, and detection of recurrence. Fluorodeoxyglucose-positron emission tomography has evolved as an imaging modality that further improves staging as well as the detection of recurrent and metastatic disease.

Septal thickening: HRCT findings and differential diagnosis

Thickening of the interlobular septa is a common and easily recognized high-resolution computed tomography feature of many diffuse lung diseases. In some cases, it is the predominant radiological finding. This article reviews the spectrum of entities that commonly present with thickening of the interlobular septa as the main radiological feature and establishes a practical approach for the differential diagnosis.

Pulmonary tumor embolism: a review of the literature

Dyspnea in a patient with cancer may have several causes, including infection, thromboembolism, metastases, and therapeutically induced cardiopulmonary disease. Pulmonary tumor embolism is an uncommon cause. Occlusion of the pulmonary microvasculature by tumor cells and associated thrombi can produce a subacute and progressive clinical picture that resembles thromboembolic disease. Unfortunately, microscopic tumor embolism is recognized rarely before death because of difficulty in establishing the diagnosis. We provide a review of the literature about the evaluation and diagnosis of this rare clinical entity.

Distribution of lung disease

Radiologists rely on imaging patterns to arrive at a diagnosis. The different morphological patterns in the lungs are well known, but less emphasis has traditionally been placed on the pattern of distribution. This important feature greatly assists in the differential diagnosis regarding many pulmonary diseases and is the focus of this article. Chest radiographs often result in a narrow differential if one understands the regional differences and microenvironments within the lung and takes into consideration the ancillary imaging findings. High-resolution computed tomography offers additional information at the level of the secondary pulmonary lobule to fine-tune the distribution pattern and, consequently, the differential diagnosis. Disease distribution is often as important as the morphologic appearance of the disorder. This article will approach pulmonary diseases from the perspective of distribution patterns, highlighting the more common patterns. The goal of this review article is to give radiologists a conceptual framework that may be applied in their daily work environment.

Multinodular disease: anatomic localization at thin-section CT--multireader evaluation of a simple algorithm

PURPOSE

To evaluate the interobserver variability and accuracy of an algorithm for anatomic localization of small nodules evident on thin-section computed tomographic (CT) images of the lungs.

MATERIALS AND METHODS

Four experienced chest radiologists independently evaluated thin-section CT images in 58 patients by using an algorithm and a standard score sheet. Nodules were placed into four possible anatomic locations or categories: perilymphatic, random, associated with small airways disease, or centrilobular. Algorithm accuracy was assessed by comparing the localization by the observers to that expected for each specific disease in the study group on the basis of reports in the literature. Interobserver variability was assessed by placing cases into one of three groups: (a) complete concordance, (b) triple concordance, and (c) discordant.

RESULTS

All observers agreed in 79% (46 of 58) of the cases with regard to nodule localization; three of the four concurred in an additional 17% (10 of 58). The observers were correct in 218 (94%) of 232 localizations in the 58 cases. There were no apparent differences in the number of either discordant or incorrect localizations between the observers. The most noteworthy source of error and of disagreement between observers was the confusion of perilymphatic and small airways disease-associated nodules in a small number of cases.

CONCLUSION

The proposed algorithm is reproducible and accurate in the majority of cases and facilitates nodule localization at thin-section CT.

Intrapulmonary metastasis of lung cancer: soft x-ray investigation of inflated and fixed lung

BACKGROUND

Intrapulmonary metastasis (IPM) of lung cancer is thought to be an important factor influencing patient prognosis. It is not easy to detect a small IPM by preoperative examination and sometimes even by postoperative pathologic investigation. We applied soft x-ray investigation to inflated and fixed lungs for the detection of IPM.

STUDY DESIGN

From 1990 to 1992, 75 patients with lung cancer who had no metastatic lesions on preoperative whole CT, MRI, and technetium-99m bone scintigram examinations underwent lung resection. The resected lungs were fixed in an inflated condition, sliced at the corresponding CT levels into 10-mm-thick sections, and submitted for soft x-ray examination. When an accessory nodular shadow(s) was detected on the soft x-ray images, the size of the nodule and its distance from the primary tumor were measured.

RESULTS

In 23 of the 75 patients, accessory nodular shadows were detected on the soft x-ray images. Six nodules in 6 patients proved to be IPM, 2 of which were also detected by postoperative macroscopic examination. Another 2 microscopic IPM were found only by postoperative pathologic examination. The total detection rate of IPM was 10.7% (8 of 75 patients) in this series. The detection rate of IPM at our institute was 5.4% before this study (1979 to 1989). The mean diameter of the IPM detected by the soft x-ray method was 2.8 +/- 1.5 mm, and this was significantly smaller than that of the macroscopically detected nodules (7.2 +/- 3.2 mm).

CONCLUSIONS

Our data show that soft x-ray investigation is an effective procedure to detect relatively small intrapulmonary metastatic nodules and will contribute to precise postoperative staging of patients with lung cancer.

CT of pulmonary metastases with pathological correlation

CT, including high-resolution CT, has become an essential means of imaging to evaluate pulmonary metastases. The underlying pathological processes of pulmonary metastases can be observed well on CT images, but they are not always specific. Several important CT features correlate with histopathological findings: (1) margin of nodule; (2) hemorrhage accompanying a metastatic nodule; (3) calcification; (4) cavitation; (5) sterilized metastasis; (6) small metastatic nodules in the lobules; (7) lymphangitic carcinomatosis; (8) tumor emboli; and (9) pleural metastases. For reasonable use of CT in pulmonary metastases, these various CT manifestations and their limitations must be understood.

High-resolution computed tomography and diffuse lung disease

Diffuse lung diseases are often difficult to characterize on chest radiographs. It has been a challenge for the radiologist to obtain useful diagnostic information from these studies and then communicate that information to the clinician. Robert Heitzman recognized the utility of understanding lung diseases in terms of their effect on the structures of the secondary lobule. Unfortunately, he needed inflated lung specimens to reliably visualize the small structures within the secondary lobule. Such specimens are no longer needed. High-resolution computed tomography (HRCT) scans of the lung provide an excellent representation of the secondary lobule. In this monograph, we have attempted to explain the normal anatomy of the secondary lobule, the patterns of abnormality, the technique for performing HRCT, and an approach to diffuse lung disease. In the second half of the article we have classified the more common diffuse lung diseases according to the dominant pathologic change: high versus low attenuation.

High resolution computed tomography of inflation-fixed lungs: pathologic-radiologic correlation of pulmonary lesions in patients with leukemia, lymphoma, or other hematopoietic proliferative disorders

The accuracy of high resolution computed tomography (HRCT) in the diagnosis of pulmonary lesions arising in patients with leukemia, lymphoma, or other hematopoietic proliferative disorders was evaluated in postmortem lung specimens from 35 patients with one of these neoplasms. Lungs were obtained from autopsied patients and prepared in a manner that allowed for direct pathologic-radiologic correlation. Eighty-eight pulmonary lesions with one of five radiographic patterns were identified in these 35 lungs. The gross, histologic, and radiographic changes were examined and the radiologic and pathologic diagnoses for each lesion were compared. A diffuse alveolar pattern on HRCT was primarily the result of pneumonia or intraalveolar hemorrhage, while irregular focal densities were produced by foci of hemorrhage, infarcts, lymphoma, and fungal infections. HRCT of the lung from a patient with pulmonary histiocytosis X showed a wedge-shaped subpleural density in association with a "crab-like" interstitial pattern, which was histologically shown to be an infarct with interstitial enlargement by infiltration of histiocytosis X. Air bronchograms were seen in two settings. In patients with necrotizing pneumonia, air bronchograms were associated with bronchiectasis. In contrast, air bronchograms seen in a patient with a bronchocentric lymphoproliferative disorder showed a pattern of bronchial constriction. These results suggest that HRCT may play an important role in the evaluation of pulmonary lesions in patients with leukemia, lymphoma, or other hematopoietic malignancies.