Focal interstitial fibrosis manifesting as nodular ground-glass opacity: thin-section CT findings

The purpose of this study was to describe the thin-section computed tomographic (CT) features of focal interstitial fibrosis manifesting as nodular ground-glass opacity (GGO) and its changes during follow-up. The thin-section CT findings of pathologically proven focal interstitial fibrosis manifesting as nodular GGO were retrospectively evaluated in nine patients (five women and four men; mean age, 59.3 years; age range, 34–81 years). The thin-section CT findings of each lesion were analyzed for multiplicity, location, shape, margin characteristics, pleural retraction or vascular convergence, size and internal attenuation, lesion internal features and lesion changes on follow-up CT scans (mean 90 days, range 5 to 215 days). All lesions manifested as a solitary nodular GGO (100%), and seven of the nine lesions (77.8%) were located in the upper lobe. Focal interstitial fibrosis was round or oval in shape in five cases (55.6%), complex in shape in three cases (33.3%) and polygonal in one case (11.1%). Lesion margins were smooth in five patients (55.6%), irregular in three (33.3%) and spiculated in one (11.1%). Pleural retraction or vascular convergence was present in two patients (22.2%). Lesions measured 4.8 mm to 25.5 mm (mean, 11.5 mm) and had attenuations ranging from −151 to −699 HU (mean, −514.7 HU). Eight (88.9%) manifested as pure nodular GGOs and one as mixed GGO with a spiculated margin. In all patients, no lesion changes were observed in follow-up CT scans. Focal interstitial fibrosis manifesting as nodular GGO usually presents as a solitary nodule with pure GGO on thin-section CT, which does not change significantly during follow-up.     

Thin-section CT features of intrapulmonary lymph nodes

PURPOSE: The objective of this study was to evaluate CT findings of pathologically proven intrapulmonary lymph nodes (IPLNs) and discuss the utility of thin-section CT and contrast-enhanced CT. METHOD: CT findings of 18 nodules in 14 patients with pathologically proven IPLNs were reviewed. CT scanning of the whole lung was performed contiguously with slice thickness of 10 mm. In addition, a helical scan with slice thickness of 2 mm was performed in nine patients, focusing on the nodule. Contrast-enhanced helical CT was performed in four patients, and the utility of thin section CT and contrast-enhanced CT was investigated. RESULTS: One patient had three nodules, 2 patients had two nodules, and the remaining 11 patients had a solitary nodule. All nodules were located below the level of the carina and within 15 mm of the pleura. In one case, conventional CT revealed the nodule 20 mm away from the pleura; however, the nodule attached to the major fissure was clearly revealed on thin-section CT. The size of the nodules was < or =15 mm, and the shape was round (n = 8), oval (n = 9), or lobulated (n = 1) with sharp border. One nodule demonstrated a spiculated border due to a surrounding pulmonary fibrosis on conventional CT; however, thin-section CT showed precisely a sharp border. The lobulated shape of one case histopathologically reflected a hilus of lymph node. On contrast-enhanced helical CT, all four nodules were enhanced and the degree enhancement was 36-85 HU (median 66.6 HU). CONCLUSION: In current times, IPLNs are not uncommon lesions. We should consider IPLN in the differential diagnosis of solitary or multiple pulmonary nodules in the peripheral field and below the level of the carina. Thin-section CT showed precisely the border or relation between IPLNs and the surrounding structure. It was difficult to distinguish between IPLNs and malignant nodules from the degree of enhancement on contrast-enhanced CT. On thin-section and contrast-enhanced CT, the findings of IPLNs are not necessarily specific. Therefore, strict observation on CT is necessary; in certain cases that are increasing in size, video-assisted thoracic surgery should be considered because of their location.     

Progression of focal pure ground-glass opacity detected by low-dose helical computed tomography screening for lung cancer

OBJECTIVE: To clarify the progression of focal pure ground-glass opacity (pGGO) detected by low-dose helical computed tomography (CT) screening for lung cancer. METHODS: A total of 15,938 low-dose helical CT examinations were performed in 2052 participants in the screening project, and 1566 of them were judged to have yielded abnormal findings requiring further examination. Patients with peripheral nodules exhibiting pGGO at the time of the first thin-section CT examination and confirmed histologically by thin-section CT after follow-up of more than 6 months were enrolled in the current study. Progression was classified based on the follow-up thin-section CT findings. RESULTS: The progression of the 8 cases was classified into 3 types: increasing size (n = 5: bronchioloalveolar carcinoma [BAC]), decreasing size and the appearance of a solid component (n = 2: BAC, n = 1; adenocarcinoma with mixed subtype [Ad], n = 1), and stable size and increasing density (n = 1: BAC). In addition, the decreasing size group was further divided into 2 subtypes: a rapid-decreasing type (Ad: n = 1) and a slow-decreasing type (BAC: n = 1). The mean period between the first thin-section CT and surgery was 18 months (range: 7-38 months). All but one of the follow-up cases of lung cancer were noninvasive whereas the remaining GGO with a solid component was minimally invasive. CONCLUSIONS: The pGGOs of lung cancer nodules do not only increase in size or density, but may also decrease rapidly or slowly with the appearance of solid components. Close follow-up until the appearance of a solid component may be a valid option for the management of pGGO.     

Organizing pneumonia: perilobular pattern at thin-section CT

PURPOSE: To describe the appearance and frequency of a perilobular pattern at thin-section computed tomography (CT) in patients with organizing pneumonia. MATERIALS AND METHODS: Thin-section CT scans of 21 consecutive patients with cryptogenic organizing pneumonia were retrospectively reviewed. Two thoracic radiologists in consensus recorded the presence and distribution of the CT abnormalities (consolidation, ground-glass opacification, nodules, bandlike opacities, interlobular septal thickening, and findings of fibrosis), with a particular focus on the presence and predominant location of the perilobular pattern, that is, a poorly defined arcadelike or polygonal appearance. RESULTS: The perilobular pattern was present in 12 (57%) of 21 patients, 10 of whom had five or more perilobular opacities. Other CT features were consolidation (20 patients, 95%), which was predominantly a subpleural and/or peribronchial distribution in 17 patients, and ground-glass opacification (18 patients, 86%). Bandlike opacities and interlobular septal thickening were observed in four patients and one patient, respectively. The perilobular pattern abutted the pleural surface in 10 of 12 patients and was surrounded by aerated lung parenchyma in 11 of 12 patients. There was no obvious relationship between perilobular opacities and CT findings indicative of established fibrosis. CONCLUSION: A perilobular pattern was present in more than half of the patients, along with the expected thin-section CT features of organizing pneumonia.     

肺孤立性磨玻璃密度结节的超高分辨力CT表现及与病理的相关性

目的：探讨肺孤立性磨玻璃密度结节的超高分辨力CT表现及与病理的相关性。方法：搜集经超高分辨力CT（UHRCT）检出并有病理结果的孤立性肺部磨玻璃密度结节（fGGN）72例,72例病灶最大径均≤2cm,回顾性分析其UHRCT表现,并与病理进行对照研究。结果：72例fGGN中纯磨玻璃密度结节（pGGN）20例,混合磨玻璃密度结节（mGGN）52例。20例pGGN中良性病变8例（40％,8／20）,其中炎症3例,局灶纤维化3例,间质或肺泡上皮增生2例;不典型腺瘤样增生（AAH）6例（30％,6／20）,细支气管肺泡癌（BAc）6例（30％,6／20）。52例mGGN中良性病变2例（3．85％,2／52）,其中慢性炎症1例,肺泡内出血1例;恶性病变50例（96．15％,50／52）,其中BACl0例,含BAc的腺癌35例,不舍BAC的腺癌5例。结论：超高分辨力CT影像上,pGGN的病理诊断以良性病变、AAH或BAC为主,而mGGN则大多为BAC及肺小腺癌。     

磨玻璃密度小肺癌CT表现与病理类型相关性研究

目的：探讨磨玻璃密度（GCO）小肺癌的CT表现与病理类型相关性。方法：搜集43例（45个）表现为纯磨玻璃密度（pGGO）或混合磨玻璃密度（mGGO）的周围型小肺癌,根据GGO占整个病灶比例的不同分三型,分别与病理对照。并有12个小肺癌术前行中长期动态观察。结果：I型（GGO成分占91％-100％）11个,病理均为细支气管肺泡癌（BAC）;II型（GGO成分占51％。90％）21个,BAC11,BAC伴高分化腺癌4个,高分化腺癌4个,中分化腺癌2个;Ⅲ型（GGO成分占≤50％）13个,BAC3个,中分化腺癌5个,低分化腺癌3个,低分化鳞癌2个;通过三型间比较发现GGO所占比例越高,小肺癌的病理分化越好,GGO成分占≥50％时,病理多数为BAC（22／32）;同时对部分小肺癌术前中长期动态观察及术后随访,发现肿瘤生长缓慢、预后良好。结论：局限性GGO不仅是周围型肺癌的重要征象之一,而且通过半定量分析GGO所占比例的多少,能一定程度上预测其病理类型、分化程度、倍增时间及预后。     

Detection of lung cancer on chest radiographs: analysis on the basis of size and extent of ground-glass opacity at thin-section CT

PURPOSE: To evaluate the detection of small peripheral lung tumors on chest radiographs on the basis of the size of the tumor and its extent of ground-glass opacity (GGO) at thin-section computed tomography (CT). MATERIALS AND METHODS: Chest radiographs of 75 patients with peripheral carcinomas 20 mm in diameter or smaller (26 localized bronchioloalveolar carcinomas [BACs], 49 other carcinomas) and 60 normal chest radiographs were retrospectively reviewed individually by 10 radiologists. The extent of GGO within the lesions at thin-section CT was reviewed retrospectively. The detection rates for localized BAC and other carcinomas on chest radiographs were calculated and were correlated with tumor size and extent of GGO. RESULTS: The mean sensitivity for detection of small peripheral carcinomas was 58.5% +/- 8.8 (standard error) for localized BAC and was 78.6% +/- 5.1 for other carcinomas (P =.024). Lesions that were smaller than 15 mm in diameter and had an extent of GGO of 70% or greater at thin-section CT were more difficult to detect than tumors that had larger diameters or less extensive GGO (chi(2) = 8.13, df = 1, P =.004). CONCLUSION: The detection of small peripheral carcinomas on chest radiographs is influenced by tumor size and extent of GGO as seen at thin-section CT.     

Limited value of shape, margin and CT density in the discrimination between benign and malignant screen detected solid pulmonary nodules of the NELSON trial

Purpose

To evaluate prospectively the value of size, shape, margin and density in discriminating between benign and malignant CT screen detected solid non-calcified pulmonary nodules.

Material and methods

This study was institutional review board approved. For this study 405 participants of the NELSON lung cancer screening trial with 469 indeterminate or potentially malignant solid pulmonary nodules (>50 mm³) were selected. The nodules were classified based on size, shape (round, polygonal, irregular) and margin (smooth, lobulated, spiculated). Mean nodule density and nodule volume were automatically generated by software. Analyses were performed by univariate and multivariate logistic regression. Results were presented as likelihood ratios (LR) with 95% confidence intervals (CI). Receiver operating characteristic analysis was performed for mean density as predictor for lung cancer.

Results

Of the 469 nodules, 387 (83%) were between 50 and 500 mm³, 82 (17%) >500 mm³, 59 (13%) malignant, 410 (87%) benign. The median size of the nodules was 103 mm³ (range 50–5486 mm³). In multivariate analysis lobulated nodules had LR of 11 compared to smooth; spiculated nodules a LR of 7 compared to smooth; irregular nodules a LR of 6 compared to round and polygonal; volume a LR of 3. The mean nodule CT density did not predict the presence of lung cancer (AUC 0.37, 95% CI 0.32–0.43).

Conclusion

In solid non-calcified nodules larger than 50 mm³, size and to a lesser extent a lobulated or spiculated margin and irregular shape increased the likelihood that a nodule was malignant. Nodule density had no discriminative power.     

New classification of small pulmonary nodules by margin characteristics on high-resolution CT.

PURPOSE: To analyze margin characteristics of pulmonary nodules on high-resolution CT (HRCT) in order to improve imaging diagnoses. MATERIAL AND METHODS: HRCT images of 193 pulmonary nodules of less than 30 mm maximum diameter (113 primary cancers, 15 metastatic cancers, 55 inflammatory nodules, and 10 benign tumors) were reviewed and classified as to 6 types of margins: round, lobulated, densely spiculated, ragged, tentacle or polygonal and halo. The relationships of these imaging types to the diagnoses, the underlying pathological features, mainly those of tumor growth patterns in 93 neoplasms, and the pathological characteristics of 14 inflammatory nodules were investigated. RESULTS: Eighty-two percent of the lobulated, 97% of the densely spiculated, 93% of the ragged and 100% of the halo nodules were malignant. Eighty percent of the tentacle or polygonal nodules were inflammatory and 66% of the round ones were benign. The 6 types differed statistically as to the nature of the benignity/malignancy (p<0.001). Pathologically, in case of neoplasms, most of the 6 types had a relationship to a particular tumor growth pattern. CONCLUSION: This HRCT classification method is useful for determining the nature of small pulmonary nodules and reflects the underlying pathological characteristics.     

Peripheral lung adenocarcinoma: correlation of thin-section CT findings with histologic prognostic factors and survival

PURPOSE: To evaluate the prognostic importance of thin-section computed tomographic (CT) findings of peripheral lung adenocarcinomas. MATERIALS AND METHODS: The subjects were 127 patients with adenocarcinomas smaller than 3 cm in largest diameter who underwent at least a lobectomy with hilar and mediastinal lymphadenectomy. The margin characteristics of nodules and the extent of ground-glass opacity (GGO) within the nodules at preoperative thin-section CT were analyzed retrospectively. Regional lymph node metastasis (LNM) and vessel invasion (VI) were histologically examined in surgical specimens. Survival curves were calculated according to the Kaplan-Meier method. RESULTS: The frequencies of LNM (4% [1 of 24]) and VI (13% [three of 24]) in adenocarcinomas with GGO components of more than 50% were significantly lower than those with GGO components of less than 10% (LNM, P <.05; VI, P <.01). The patients with GGO components of more than 50% showed a significantly better prognosis than those with GGO components less than 50% (P <.05). All 17 adenocarcinomas smaller than 2 cm with GGO components of more than 50% were free of LNM and VI, and all these patients are alive without recurrence. Coarse spiculation and thickening of bronchovascular bundles around the tumors were observed more frequently in tumors with LNM or VI than in those without LNM or VI (P <.01). CONCLUSION: Thin-section CT findings of peripheral lung adenocarcinomas correlate well with histologic prognostic factors.     

Malignant Pure Pulmonary Ground-Glass Opacity Nodules: Prognostic Implications

Objective

This study was designed to evaluate follow-up results in terms of patient prognosis for malignant pulmonary nodules depicted as pure ground-glass opacity (GGO) lesion observed at high-resolution CT (HRCT).

Materials and Methods

Surgical removal for malignant GGO nodules was accomplished in 58 patients (26 men, 32 women; mean age, 57 years; age range, 29-78 years). Patient prognoses were assessed by patient clinical status and the presence of changes in nodule size determined after a follow-up HRCT examination. Differences in patient prognoses were compared for nodule number, size, surgical method, change in size before surgical removal, and histopathological diagnosis by use of Fisher''s exact test and Pearson''s chi-squared test.

Results

Of the 58 patients, 40 patients (69%) were confirmed to have a bronchioloalveolar carcinoma (BAC) and 18 patients (31%) were confirmed to have an adenocarcinoma with a predominant BAC component. Irrespective of nodule size, number, treatment method, change in size before surgical removal and histopathological diagnosis, neither local recurrence nor a metastasis occurred in any of these patients as determined at a follow-up period of 24 months (range; 12-65 months). Of 14 patients with multiple GGO nodules, all of the nodules were resected without recurrence in six patients. In the remaining eight patients, the remaining nodules showed no change in size in seven cases and a decrease in size in one case as determined after a follow-up CT examination.

Conclusion

Prognoses in patients with pure GGO malignant pulmonary nodules are excellent, and not significantly different in terms of nodule number, size, surgical method, presence of size change before surgical removal and histopathological diagnosis.     

Nontuberculous mycobacterial pulmonary infection in immunocompetent patients: comparison of thin-section CT and histopathologic findings

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 infection. Regardless of the specific infective mycobacterial species, bilateral small nodules (in 22 [100%] lung locations), cylindric bronchiectasis (in 20 [91%] locations), and branching centrilobular nodular lesions (in 17 [77%] locations) were the most common CT findings seen at the biopsy sites. All of the transbronchial lung biopsy specimens showed a thickened bronchiolar wall and bronchiolar and peribronchiolar inflammation at histopathologic analysis. Dilated bronchioles were identified in 19 (86%) patients, and epithelioid granulomas with or without caseation were seen in seven (32%). CONCLUSION: Regardless of the specific infective mycobacterial species, the most common thin-section CT findings of NTM pulmonary infection are bilateral small nodules, cylindric bronchiectasis, and branching centrilobular nodules. These findings correspond histopathologically to bronchiolectasis and bronchiolar and peribronchiolar inflammation with or without granuloma formation.     

Nodular Ground-Glass Opacities on Thin-section CT: Size Change during Follow-up and Pathological Results

Objective

To evaluate the inter-group differences in growth and the pathological results of nodular ground-glass opacities (GGOs) according to their size and focal solid portions.

Materials and Methods

Ninety-six nodular GGOs in 55 individuals followed by CT for at least one month from an initial chest CT were included. Forty nodular GGOs in 30 individuals were pathologically confirmed to be: adenocarcinoma (n = 15), bronchioloalveolar carcinoma (BAC) (n = 11), atypical adenomatous hyperplasia (AAH) (n = 8), focal interstitial fibrosis (n = 5) and aspergillosis (n = 1). Lesions were categorized based on high-resolution CT findings: pure nodular GGO (PNGGO) ≤ 10 mm, PNGGO > 10 mm, mixed nodular GGO (MNGGO)≤ 10 mm, and MNGGO > 10 mm. In each group, the change in size during the follow-up period, the pathological results and the rate of malignancy were evaluated.

Results

Three MNGGO lesions, and none of the PNGGO, grew during the follow-up period. Resected PNGGOs ≤ 10 mm were AAH (n = 6), BAC (n = 5), and focal interstitial fibrosis (n = 1). Resected PNGGOs > 10 mm were focal interstitial fibrosis (n = 4), AAH (n = 2), BAC (n = 2), and adenocarcinoma (n = 2). Resected MNGGOs ≤ 10 mm were adenocarcinoma (n = 2), and BAC (n = 1). Resected MNGGOs > 10 mm were adenocarcinoma (n = 11), BAC (n = 3), and aspergillosis (n = 1).

Conclusion

Mixed nodular GGOs (MNGGOs) had the potential for growth; most were pathologically adenocarcinoma or BAC. By contrast, PNGGOs were stable for several months to years; most were AAH, BAC, or focal interstitial fibrosis.     

Mucin-producing adenocarcinoma of the lung: thin-section computed tomography findings in 48 patients and their effect on prognosis

OBJECTIVE: To determine the prognostic value of thin-section computed tomography (CT) findings in patients with mucin-producing adenocarcinoma (MPA) of the lung. METHODS: The study included 48 patients with pathologically proven MPA who had thin-section CT before treatment. The CT findings were correlated with the histopathologic findings and with disease-free survival on follow-up in all patients. RESULTS: Computed tomography findings identified in patients with MPA of the lung included an air bronchogram (n = 37, 77.1%), areas of ground-glass attenuation (n = 36, 75.0%), areas of air-space consolidation (n = 36, 75.0%), interlobular septal thickening (n = 33, 68.8%), bubble-like lucencies (n = 23, 47.9%), centrilobular nodules (n = 22, 45.8%), and mucus filling of airways (n = 19, 39.6%). Twenty-two (45.8%) of the 48 patients had intrapulmonary metastases. Centrilobular nodules (odds ratio [OR] = 6.7, 95% confidence interval: 1.1-41.4; P < 0.05) and mucus filling of airways (OR = 14.4, 95% 95% confidence interval: 2.0-102.7; P < 0.01) on thin-section CT were independently associated with an increased likelihood of intrapulmonary metastases. The 5-year disease-free survival rates were 67.9% and 38.4% for patients without and with intrapulmonary metastases, respectively (P < 0.05). The presence of centrilobular nodules (relative risk = 10.5, 95% confidence interval: 1.8-59.3; P < 0.01) on thin-section CT was an independent predictor of poor prognosis. CONCLUSION: Centrilobular nodules on CT are associated with a higher prevalence of intrapulmonary metastases and a poor prognosis in patients with MPA of the lung.     

Indeterminate solitary pulmonary nodules revealed at population-based CT screening of the lung: using first follow-up diagnostic CT to differentiate benign and malignant lesions

OBJECTIVE: We studied the role of the first follow-up diagnostic CT for differentiating benign and malignant lesions in indeterminate solitary pulmonary nodules revealed at CT screening for lung cancer in which a total of 13,786 CT examinations (46% in women and 54% in men; 46% were smokers; mean age, 62 years) were performed. MATERIALS AND METHODS: We reviewed thin-section CT findings on the initial diagnostic CT (lesion size; percentages of ground-glass-opacity areas of lesion; and presence or absence of lobulation, spiculation, air bronchogram, cavity, satellite lesions, pleural tag, concave margins, polygonal shape, and peripheral subpleural lesion) in 80 pulmonary nodules (36 malignancies and 44 benign lesions) of 80 patients. We evaluated changes in size (regression, no change, or growth) on the first follow-up CT performed 42-120 days (mean, 93 days) after the initial CT. RESULTS: The greatest accuracy (81%) with 89% sensitivity and 75% specificity for determining malignancy was attained with a combined criterion of growth of lesions or predominantly ground-glass-opacity lesions. Of all criteria that were specific to malignancy, the greatest sensitivity (50%) was achieved with a combination of growth or no change in size of lesions and predominantly ground-glass opacity and no concave margins. Of all criteria that were specific to benign lesions, the greatest sensitivity (45%) was attained with a combination of lesion regression or polygonal shape. CONCLUSION: Follow-up CT findings were useful, and a combination of findings on initial CT and follow-up CT was optimal for differentiating benign and malignant pulmonary nodules.     

MSCT后处理技术对真菌性肺炎的诊断及鉴别诊断价值

目的：探讨多层螺旋CT薄层图像与MPR图像在诊断真菌性肺炎中的临床价值,提高对该病的诊断水平。方法：搜集45例具有完整临床、实验室检查、病理组织学及CT检查资料的肺部真菌感染病例,回顾性分析其常规CT图像、薄层图像及MPR图像的CT征象。结果：白色念珠菌感染12例,曲霉菌感染14例,隐球菌感染8例,毛霉菌感染5例,放线菌感染3例,马尔尼菲青霉菌感染3例。肺部真菌感染的CT表现如下：空洞为主型15例,表现为一个或几个肺叶内单发或多发大小不等空洞性病灶,部分空洞周围见“晕征”,部分空洞内呈典型“鸟巢征”;肺炎样实变或支气管肺炎样变16例,呈小片状或大片状阴影,见支气管充气征及周边密度趋淡即“晕征”;结节或肿块8例,结节或肿块可伴有空洞、“晕征”、毛刺或分叶征;曲菌球6例,呈圆形或椭圆形,并可见“新月征”。薄层CT图像结合MPR图像在显示“晕征”、磨玻璃影、网格、线样影及小结节等cT征象明显优于普通cT（P〈0．05）,其余征象无明显差异（P〉0．05）,但薄层cT结合MPR图像能更清楚地显示病灶范围。结论：多层螺旋CT薄层图像结合MPR图像有助于肺真菌感染的诊断,真菌性肺炎有一定相对特征性改变,掌握真菌性肺炎的CT表现特征,结合临床综合分析,可提高诊断准确性。     

Computerized detection of lung nodules in thin-section CT images by use of selective enhancement filters and an automated rule-based classifier

RATIONALE AND OBJECTIVES: We have been developing a computer-aided diagnostic (CAD) scheme for lung nodule detection in order to assist radiologists in the detection of lung cancer in thin-section computed tomography (CT) images. MATERIALS AND METHODS: Our database consisted of 117 thin-section CT scans with 153 nodules, obtained from a lung cancer screening program at a Japanese university (85 scans, 91 nodules) and from clinical work at an American university (32 scans, 62 nodules). The database included nodules of different sizes (4-28 mm, mean 10.2 mm), shapes, and patterns (solid and ground-glass opacity (GGO)). Our CAD scheme consisted of modules for lung segmentation, selective nodule enhancement, initial nodule detection, feature extraction, and classification. The selective nodule enhancement filter was a key technique for significant enhancement of nodules and suppression of normal anatomic structures such as blood vessels, which are the main sources of false positives. Use of an automated rule-based classifier for reduction of false positives was another key technique; it resulted in a minimized overtraining effect and an improved classification performance. We used a case-based four-fold cross-validation testing method for evaluation of the performance levels of our computerized detection scheme. RESULTS: Our CAD scheme achieved an overall sensitivity of 86% (small: 76%, medium-sized: 94%, large: 95%; solid: 86%, mixed GGO: 89%, pure GGO: 81%) with 6.6 false positives per scan; an overall sensitivity of 81% (small: 69%, medium-sized: 91%, large: 91%; solid: 79%, mixed GGO: 88%, pure GGO: 81%) with 3.3 false positives per scan; and an overall sensitivity of 75% (small: 60%, medium-sized: 88%, large: 87%; solid: 70%, mixed GGO: 87%, pure GGO: 81%) with 1.6 false positives per scan. CONCLUSION: The experimental results indicate that our CAD scheme with its two key techniques can achieve a relatively high performance for nodules presenting large variations in size, shape, and pattern.     

Amyloidosis and lymphoproliferative disease in Sjögren syndrome: thin-section computed tomography findings and histopathologic comparisons

OBJECTIVE: To describe the thin-section computed tomography (CT) findings of Sjogren syndrome accompanying pulmonary amyloidosis and lymphoproliferative disease and to compare these with histopathologic findings. SUBJECTS AND METHODS: The thin-section CT findings of 5 women (age range: 42-59 years, mean age=50 years) with primary Sjogren syndrome accompanying pulmonary amyloidosis and lymphoproliferative disease were reviewed retrospectively by 2 chest radiologists, and decisions on findings were reached by consensus. The pathologic specimens of parenchymal lesions (nodules, dense consolidation, and cystic lesion at CT) obtained using video-assisted thoracoscopic surgery were studied to compare with the thin-section CT findings. RESULTS: Nodules, observed in all 5 patients, were variable in size and ranged from 3 to 24 mm (mean=9.9 mm) in diameter, with lobulated or irregular margins. Nodular calcifications were present in 3 patients. Cysts, which also were observed in all patients, ranged from 4 to 45 mm (mean=18.6 mm) in diameter, with a thin (1-2 mm) or no visible wall. Multiple cysts were observed, especially in the distal portion of narrowed bronchioles. Nodules and cysts showed a random distribution. Mild bronchial wall thickening with bronchial dilatation was seen in all patients, ground-glass opacities were seen in 3, and consolidation was seen in 1. Nodules, consolidation, and bronchial wall thickening at CT were caused histopathologically by the interstitial and peribronchiolar deposition of mixed amyloid and lymphoproliferative cells. Cysts lined with respiratory epithelium contained amyloid deposition and lymphoproliferative cells in their walls. CONCLUSION: Sjogren syndrome accompanying pulmonary amyloidosis and lymphoproliferative disease manifests as multiple, large, thin-walled cysts; multiple nodules; parenchymal opacity; and bronchiectasis. These findings are caused by the interstitial or peribronchial infiltration of mixed amyloid and lymphoproliferative cells.     

肺腺癌的螺旋CT表现特征及其病理学基础

目的：探讨肺腺癌局部生长的螺旋CT表现特点与组织病理基础的基础关性。方法：34例手术病理证实的肺腺癌采用扫描。结合组织病理发现，观察和评价和评价在螺旋CT上肿瘤内部结构，密度分布、边缘特征及周围肺组织改变。结果：34例肺腺癌中，肿块密度均匀14例（41％），不均匀20例（59％），分叶片22例（65％），空泡征10例（29％），短毛刺16例（47％），支气管气相7例（21％），血管集束征16例（47％），胸膜凹陷征19例（56％），毛玻璃样（ground galass opacity,GGO)征7例（21％），GGO征病理上代表肿瘤细胞沿肺泡壁生长，同时残留含气肺泡组织。结论：肺腺癌的螺旋CT表现可反映肿瘤生长的组织病理学特征。