Pleural invasion by peripheral lung cancer: prediction with three-dimensional CT.

RATIONALE AND OBJECTIVES: To evaluate the clinical utility of three-dimensional (3D) computed tomography (CT) for predicting pleural invasion by peripheral lung cancer. MATERIALS AND METHODS: CT findings (tumor size, vertical diameter, length and area of the interface between tumor and the pleura, ratios of length and area [Rarea] of interface between tumor and the pleura to tumor size, angle between the tumor and adjacent pleura, presence or absence of pleural thickening, and originally developed 3D pleural patterns) in 201 consecutive patients with lung cancer of ≤3 cm in contact with pleural surface were correlated with pathologic findings. Logistic modeling was used for determining the significant factors for prediction of pleural invasion, and receiver operating characteristic (ROC) curves were used for investigating diagnostic capability of significant factors, resulting in a recommendation to the optimal criteria for predicting pleural invasion and to the optimal threshold for differentiating parietal from visceral invasion. RESULTS: Sixty-one (30%) of the 201 patients had pathologically verified pleural invasion. Logistic modeling revealed that the 3D pleural pattern was the only significant factor (P < .001; relative risk of 7.34). Among every combination of the 3D patterns, skirt-like pattern showed the highest accuracy of 77% for predicting pleural invasion. In differentiating parietal from visceral pleural invasion, ROC analysis revealed that Rarea was optimal for differentiating parietal from visceral pleural invasion, and the highest accuracy of 77% was obtained with a cut-off value of 13.4 for this criterion. CONCLUSIONS: Computer-aided 3D CT analysis of the pleura was useful for predicting pleural invasion.

Thin-section CT findings in peripheral lung cancer of 3 cm or smaller: are there any characteristic features for predicting tumor histology or do they depend only on tumor size?

BACKGROUND: Ground-glass opacity (GGO) is reported to be characteristic to lepidic growth of neoplasm in subsolid nodules. In solid nodules of lung cancer, however, there is no characteristic feature to be reported. PURPOSE: To study if there are any thin-section CT findings characteristic to tumor histology or if they are only related to tumor size in solid nodules of the lung cancer. MATERIAL AND METHODS: This study included 106 solid peripheral lung cancers of 3 cm or smaller (56 adenocarcinomas, 33 squamous cell carcinomas, and 17 small cell carcinomas) in which 16-slice CT with 1 mm collimation was performed before surgery. Six morphologic findings (presence or absence of lobulation, coarse spiculation, air bronchogram, cavity, pleural tag, and pleural-based lesion) and four measurements (ratio of the greatest transverse and vertical diameter to the shortest transverse diameter and density of lobulation and coarse spiculation) on thin-section CT images were evaluated. Density of lobulation (coarse spiculation) was defined as the ratio of lobulation (coarse spiculation) number to the greatest transverse diameter of a nodule. RESULTS: Air bronchogram (P < 0.01) was the only significant factor for predicting lung adenocarcinoma. The prevalence of air bronchogram was significantly greater in adenocarcinoma than in squamous cell carcinoma (P < 0.01) or small cell carcinoma (P < 0.01). As the tumor size advanced, significantly positive linear trends were seen in the prevalence of lobulation (P < 0.01), coarse spiculation (P < 0.01), and pleural tag (P < 0.01), and the mean values of density of lobulation (P < 0.01) and coarse spiculation (P < 0.01), while the significant negative linear trend was seen in the ratio of vertical diameter to the shortest transverse (P = 0.02). CONCLUSION: Air bronchogram on thin-section CT is characteristic feature of solid adenocarcinoma of the lung. However, other thin-section CT findings are irrelevant to tumor histology and related only to tumor size.

Differentiation of lung neoplasms with lepidic growth and good prognosis from those with poor prognosis using computer-aided 3D volumetric CT analysis and FDG-PET.

BACKGROUND: Many studies have reported that transverse computed tomography (CT) imaging findings correlate with prognosis of patients with small peripheral lung neoplasm with lepidic growth. However, no studies have examined this correlation with the aid of three-dimensional (3D) CT data. PURPOSE: To determine the most efficacious imaging factor for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis. MATERIAL AND METHODS: We evaluated CT findings, nodule patterns, SUVmax on FDG-PET/CT, as well as nodule volume and ratios of solid parts to nodule volume that were semi-automatically measured on CT images of 64 pulmonary nodules of ≤ 2 cm in 60 consecutive patients (24 men and 36 women; mean age, 65 years). For logistic modeling, we used all of the significant factors observed between the neoplasms with good and with poor prognosis as independent variables to estimate the statistically significant factors for discriminating invasive adenocarcinomas with lepidic growth (lesions with poor prognosis, n=42) from the other neoplasms, including preinvasive lesions (lesions with good prognosis, n=22), resulting in a recommendation for the optimal criterion for predicting lesions with poor prognosis. RESULTS: The logistic regression model identified the ratio of the solid part to the whole volume of a pulmonary nodule as the only significant factor (P=0.04) for differentiating lepidic growth type lung neoplasms with good prognosis from those with poor prognosis. A ratio of 0.238 or more showed the highest discriminatory accuracy of 84% with 91% sensitivity and 76% specificity. CONCLUSION: Computer-aided analyses of pulmonary nodules proved most useful for establishing the optimal criterion for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis.

Adenocarcinoma of the lung with scattered consolidation: radiological-pathological correlation and prognosis.

PURPOSE: To investigate the clinicopathological features and prognosis in patients with adenocarcinoma of the lung with scattered consolidation (ALSC). MATERIALS AND METHODS: Between January 2006 and March 2010, 139 consecutive patients with lung adenocarcinoma of ≤3 cm, who underwent pulmonary resection for lung cancer, were investigated retrospectively. Radiologic classification was based on the findings of thin-section CT such as the presence of consolidation or ground-glass opacity (GGO). Type I (n=15) and Type II (n=14), showed a pure GGO and a mixed GGO with consolidation <50%, respectively. Type IV (n=38) and Type V (n=52) showed a mixed GGO with consolidation ≥50% and a pure consolidation, respectively. Type III (n=20) was the adenocarcinoma of the lung with scattered consolidation (ALSC). The clinicopathological features and prognosis of ALSC was investigated with comparative analysis and survival analysis. RESULTS: Because of the similar recurrence rate for Type I and Type II (P=1.000), Type IV and Type V (P=0.343), we merged Type I and Type II as Type I+II, Type IV and Type V as Type IV+V, respectively. In the 20 (14.4%) patients with ALSC, lymph node metastasis was not observed, and it was rare in lymphatic invasion and vascular invasion. On the basis of IASLC/ATS/ERS 2011 classification, 80% of the ALSC were preinvasive lesions. In Noguchi classification, there was no significant difference between Type I+II and ALSC (P=0.260). The prognosis of ALSC was similar to Type I+II (P=0.408), but better than Type IV+V (P=0.040). CONCLUSION: Adenocarcinoma of the lung with scattered consolidation (ALSC) on thin-section CT was a relatively favorable prognostic factor.

Diagnosis of regional node metastases in lung cancer with computer-aided 3D measurement of the volume and CT-attenuation values of lymph nodes.

RATIONALE AND OBJECTIVES: The aim of this study is to assess the usefulness of computer-aided three-dimensional (3D) measurement of volume and computed tomography (CT) attenuation values of nodes for diagnosing nodal metastases of lung cancer. MATERIALS AND METHODS: We measured three diameters, their ratios, volume, and CT values in 3D images of 191 nodes (64 malignant; 162 of <1 cm in short diameter) in 26 consecutive patients who underwent contrast-enhanced, thin-section, multidetector row CT before surgery. We separately studied statistically significant factors in a group of all nodes and in another group of nodes of <1 cm in short diameter with logistic modeling and evaluated their diagnostic accuracy. RESULTS: Significant factors were CT values (P < .001) and short diameter (P = .001) for the total node group, and CT values (P = .030) and 3D volume (P = .035) for the <1 cm node group. Optimal 83% accuracy was obtained with a criterion of short diameter of >7.4 mm and CT values of >103 Hounsfield unit (HU) for the total node group, whereas optimal 76% accuracy was obtained with a criterion of 3D volume of >1282 mm(3) or CT values of >103 HU for the <1 cm node group. CONCLUSION: 3D measurement may be useful for diagnosing nodal metastases.

F18-FDG PET-CT analyses of small peripheral adenocarcinoma of the lung.

BACKGROUND: Radiological discrimination of histologic subtypes of small peripheral adenocarcinoma of the lung is clinically important. Although there are many articles in which CT findings were used for this purpose, there are only a few reports on the capability of FDG PET-CT findings for histologic classification of this tumor. PURPOSE: To investigate the correlation between visual assessment or maximum standard uptake values (SUVmax) on F18-FDG PET-CT and histology grading of small peripheral adenocarcinoma of the lung. MATERIAL AND METHODS: Proportions of positive PET-CT diagnoses and SUVmax were retrospectively reviewed on 96 solitary pulmonary nodules of ≤2 cm in 90 consecutive patients. Tumors were classified into four groups according to Noguchi's classification (group 1 [n = 10], atypical adenomatous hyperplasia and type A tumors; group 2 [n = 12], type B tumors; group 3 [n = 42], type C tumors; group 4 [n = 32], types D, E, and F tumors). Proportions of positive PET-CT diagnoses and mean SUVmax of lesions among four groups were compared using trend tests to examine if there is a significant linear correlation with the progression of the histology grading of tumors. Then, an optimal threshold of SUVmax was proposed to best discriminate tumors of poor (groups 3 and 4) from good (groups 1 and 2) prognosis. RESULTS: There was a significant linear trend for both visual assessment (P < 0.01) and SUVmax (P < 0.01). A SUVmax of 0.42 showed the highest accuracy of 84% with 95% sensitivity and 50% specificity for predicting tumors of poor prognosis. A SUVmax of 2.05 showed 100% specificity with 49% sensitivity, and 60% accuracy. Positive visual diagnoses showed accuracy of 83% with 90% sensitivity and 59% specificity. CONCLUSION: Visual assessment and SUVmax on PET-CT correlated well with the histology grading of small peripheral adenocarcinoma of the lung.

Magnetic resonance imaging of syringocystadenoma papilliferum of the external auditory canal.

Syringocystadenoma papilliferum (SCAP) usually occurs on the face or the scalp and is very rare in the external auditory canal (EAC). There has been no information on magnetic resonance (MR) imaging of this tumor irrespective of its site. We report here a case of 57-year-old man having this tumor, which was surgically removed and its histopathology was confirmed. MR imaging demonstrated a lobulated 4-cm mass with clearly defined margins in the EAC. Although the tumor was bulky, these MR findings were different from the malignancies. The mass lesion showed intermediate signal intensity both on T1- and T2-weighted MR images and showed slight enhancement on gadolinium-enhanced T1-weighted images. Signal intensities on T2-weighted images of this tumor were low compared to those of pleomorphic adenoma. All ceruminous gland tumors including SCAP are thought to be potentially malignant; therefore, pre-operative biopsy should not be performed. Even though incisional biopsy is sometimes needed as in our case, the current MR features would be helpful for differential diagnosis of this rare condition and assessing the extension of the tumor.

Infective tricuspid valve endocarditis with pulmonary emboli caused by Campylobacter fetus after tooth extraction.

We describe a case of infective endocarditis caused by Campylobacter fetus accompanied by pulmonary emboli. A 52-year-old man was referred to our hospital due to febrile temperatures with a history of dental treatment followed by eating raw meat. Computed tomography revealed multiple infiltrations and a nodule with low attenuation area and feeding vessels. A mobile mass, possible vegetation, attached to the tricuspid valve was detected by transthoracic echocardiography. Two blood cultures disclosed Campylobacter fetus. Long-term antibiotic therapy was given, curing the infection with valvuloplasty. We presented the possibility that infective Campylobacter fetus endocarditis after dental treatment was caused by eating raw meat.

Coronary artery calcification detected by a mobile helical computed tomography unit and future cardiovascular death: 4-year follow-up of 6120 asymptomatic Japanese.

In the present study, we performed a prospective follow-up study in a population which underwent chest computed tomography (CT) screening. A total of 6120 participants underwent a chest CT medical examination for lung cancer and tuberculosis in Nagano Prefecture, Japan, between 1996 and 1997. Computed tomography scanning was performed from the apex of the lung to the diaphragm at a tube voltage of 120 kV and a tube current of 50 mA. We measured the CT density of the coronary arteries in 5-7 slices where coronary arteries were detected. The CT density threshold for determining coronary artery calcification (CAC) was above +110 HU. In 2000, we investigated the number of deaths due to cardiac and noncardiac disease among the participants. Of the 6120 participants, 14 died of cardiac disease (9, myocardial infarction; 4, heart failure; and 1, angina pectoris) and 64 died of other diseases. Coronary artery calcification was detected in 10 of the patients who died of cardiac disease, and in 31 of those who died of other diseases. The prevalence of CAC was higher in the former than in the latter (71.4% vs 48.4%, P = 0.084). The relative risk of CAC for cardiac death was 2.66 (95% confidence interval: 0.76, 9.37). The findings of this study suggested that CAC detected in a mass chest CT screening by a mobile helical CT unit was predictive of future cardiovascular death.

Magnetic resonance imaging of pleomorphic adenoma arising from the external auditory canal.

Pleomorphic adenoma arising from the external auditory canal is a very rare neoplasm, and there has been no report on magnetic resonance (MR) imaging of pleomorphic adenoma of the external auditory canal. We report here a case of 65-year-old male with this tumour, measuring 12 mm in a diameter. Histopathology was confirmed from the specimen obtained at the surgical excision. MR revealed that the tumour had a well-defined margin showing hypointensity on T1-weighted images and hyperintensity on T2-weighted images relative to the parotid gland. The tumour was well enhanced by contrast material. No invasion to the surrounding tissue was observed. These MR findings were compatible with pleomorphic adenoma of the salivary gland origin. In treating pleomorphic adenoma of the external auditory canal, complete surgical excision is essential for the prevention of recurrence. It can be concluded that MR imaging is helpful for making a differential diagnosis of external auditory canal tumours and selection of adequate treatment.

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.

Small solitary pulmonary nodules (< or =1 cm) detected at population-based CT screening for lung cancer: Reliable high-resolution CT features of benign lesions.

OBJECTIVE: We assessed thin-section CT features specific to benignity in solitary pulmonary nodules of 1 cm or smaller that were detected at population-based CT screening for lung cancer. MATERIALS AND METHODS: Two reviewers independently made qualitative (presence or absence of lobulation, spiculation, air bronchogram, cavity, satellite lesions, pleural tag, concave margins, polygonal shape, and peripheral subpleural lesion) and quantitative (lesion size, percentage of ground-glass opacity areas, and two- and three-dimensional ratios of lesion) assessments in CT images of 72 nodules (25 lung cancers, seven atypical adenomatous hyperplasias, and 40 benign lesions). Optimal criteria specific to benignity were studied. RESULTS: The prevalence of polygonal shape (p = 0.005 and p = 0.019, reviewer 1 and reviewer 2), peripheral subpleural lesion (p = 0.011 and p = 0.033), a predominantly solid lesion (p < 0.001 and p < 0.001), and three-dimensional ratios (p < 0.001 and p < 0.001) were greater in benign lesions than in malignancies. The prevalence of a predominantly solid lesion (p < 0.001 and p < 0.001) was greater in benign lesions than in atypical adenomatous hyperplasias, and the prevalence of a peripheral subpleural lesion (p = 0.004 and p = 0.012) was greater in atypical adenomatous hyperplasias than in malignancies. Using a single CT feature, polygonal shape and a three-dimensional ratio of greater than 1.78 showed 100% specificity for both reviewers. Among all combinations of CT findings specific to benignity, a combined criterion of a predominantly solid lesion and peripheral subpleural lesion or polygonal shape or the three-dimensional ratio attained the highest sensitivity (63% and 60%) for both reviewers. CONCLUSION: A combined criterion of CT features was optimal for predicting benign pulmonary lesions.

CT findings and progression of small peripheral lung neoplasms having a replacement growth pattern.

OBJECTIVE: We investigated the imaging findings and progression of replacement lung neoplasms that were revealed on thin-section CT and serial CT. MATERIALS AND METHODS: We evaluated the age of patients and thin-section CT findings (lesion size; percentage of ground-glass opacity areas; and presence or absence of solid portions, lobulation, coarse spiculation, air bronchogram, cavity, multiplicity, and pleural tags) in 73 lesions (11 atypical adenomatous hyperplasias, 17 type A [Noguchi's classification], 18 type B, and 27 type C small peripheral adenocarcinomas). We compared the serial findings of 48 of 73 lesions on low-dose screening CT (n = 21) or thin-section CT (n = 27) obtained at a mean interval of 450 days (range, 85-951 days). Progression from atypical adenomatous hyperplasia through type A to type B and then to type C tumor was studied using trend tests. RESULTS: A significant linear trend was seen for lesion size (r = 0.55; p < 0.001), percentages of ground-glass opacity areas (r = 0.75; p < 0.001), and the prevalence of lobulation (p < 0.001), spiculation (p = 0.001), air bronchogram (p = 0.023), cavity (p = 0.046), pleural tag (p < 0.001), and solid portions (p < 0.001). In general from serial CT assessment, lesions were recognized first as a ground-glass opacity nodule (56% of 48 lesions) with subsequent increase in size (75%), then solid portions appeared in the nodule (17%), and finally solid portions increased (23%) with occasional augmentation of tissue contraction (6%). CONCLUSIONS: CT analysis revealed stepwise progression of replacement-type lung neoplasms.

Using MR imaging to predict invasion of the recurrent laryngeal nerve by thyroid carcinoma.

OBJECTIVE: We evaluated the accuracy of MR imaging findings for predicting invasion of the recurrent laryngeal nerve by thyroid carcinoma and established an optimal criterion on which to base this prediction. MATERIALS AND METHODS: We reviewed MR imaging findings (lesion size and posterior extension of tumor; encirclement of and invasion into the laryngeal cartilage, trachea, and esophagus by the tumor; and the amount of effaced fatty tissue in the tracheoesophageal groove or between the laryngeal cartilage and hypopharyngeal wall) in 66 patients with thyroid carcinoma. The amount of effaced fatty tissue was classified as one of five grades: 1, normal amount of fatty tissue; 2, partly effaced; 3, completely effaced in one MR imaging slice; 4, completely effaced in two contiguous MR slices; and 5, completely effaced in three or more contiguous MR slices. RESULTS: Thirty-two (48%) of the 66 patients had surgically or pathologically verified recurrent laryngeal nerve invasion. Logistic modeling revealed that the amount of effaced fatty tissue (p < 0.001) and the lesion size (p = 0.033) were the significant factors. Using the threshold values for the lesion size to predict invasion, we found that a threshold of more than 2.9 cm showed the highest accuracy, 76%, with 78% sensitivity and 74% specificity. For the amount of effaced fatty tissue, a grade of 3 or more had the highest accuracy, 88%, with 94% sensitivity and 82% specificity. Addition of the lesion size to this criterion did not improve the diagnostic accuracy of using the amount of effaced fatty tissue alone. CONCLUSION: Invasion of the recurrent laryngeal nerve by thyroid carcinoma was accurately predicted by the finding of effaced fatty tissue on MR imaging.

High-resolution CT features: prognostic significance in peripheral lung adenocarcinoma with bronchioloalveolar carcinoma components.

BACKGROUND: Based on Noguchi's classification, adenocarcinomas with bronchioloalveolar carcinoma (BAC) components have a heterogeneous prognosis. However, until now, the prognostic factors in this tumor category have not been clarified. OBJECTIVES: We studied the prognostic significance of high-resolution CT (HRCT) findings in this tumor subtype. MATERIALS AND METHODS: HRCT findings [lesion size, percentage of ground-glass opacity (GGO) areas in the lesion, presence or absence of lobulation, coarse spiculation, pleural tag, satellite lesion, air bronchogram, and site of the lesion], clinical data (age, gender and surgical method), and pathologic findings (degree of tumor differentiation and presence or absence of nodal metastasis) were analyzed in 52 consecutive patients with adenocarcinoma with BAC components <3 cm (mean, 1.7 cm). The patients included 32 women and 20 men with a mean age of 66 years. The results correlated with survival using univariate and multivariate analysis. The mean follow-up period was 41 months. RESULTS: Nine (17%) of the 52 patients died of lung cancer. In univariate analysis, a significant difference was found for lobulation (p = 0.018), %GGO (p = 0.043), air bronchogram (p = 0.003), site of lesion (p = 0.034), degree of tumor differentiation (p = 0.001), and nodal metastasis (p = 0.040). Multivariate analysis using the 6 factors that were significant in univariate analysis as independent variables revealed that an air bronchogram (p = 0.010) and the degree of tumor differentiation (p = 0.008) were significant independent factors for survival. CONCLUSION: The presence of an air bronchogram on HRCT may have an independent prognostic significance in lung adenocarcinoma with BAC components.

Esophageal invasion by thyroid carcinomas: prediction using magnetic resonance imaging.

PURPOSE: We evaluated the accuracy of magnetic resonance imaging (MRI) in predicting esophageal invasion by thyroid carcinomas and established an optimal criterion for diagnosing esophageal invasion. METHOD: The MRI findings (size and margins of tumor, ratio of tumor contact to the esophagus, shape and displacement of the esophagus, and tumor invasion to the outer and inner layers of the esophagus) in 67 patients with thyroid carcinomas were retrospectively reviewed and correlated with surgical and pathologic findings. Logistic modeling was used to determine the significant factors for predicting esophageal invasion. RESULTS: Seventeen (34%) of the 67 patients had pathologically or surgically verified esophageal invasion. The logistic modeling revealed that outer layer invasion (P < 0.001) and poorly defined margins (P = 0.001) were the significant factors. The outer layer invasion showed the highest accuracy of 91%, with 82% sensitivity and 94% specificity. The addition of poorly defined margins to this criterion did not improve its accuracy. CONCLUSION: Esophageal invasion by thyroid carcinoma was accurately predicted with MRI, and an MRI finding of outer layer invasion was optimal for diagnosing esophageal invasion.

Prognostic significance of high-resolution CT findings in small peripheral adenocarcinoma of the lung: a retrospective study on 64 patients.

OBJECTIVE: We studied the prognostic importance of high-resolution CT (HRCT) findings in lung adenocarcinomas. PATIENTS AND METHODS: HRCT findings (lesion size, percentage of ground-glass opacity (GGO) areas of lesion, and presence or absence of lobulation, coarse spiculation, air space, pleural tag, and multiplicity of lesion), clinical data (age and surgical method), and pathologic findings (tumor subtypes and presence or absence of nodal metastasis) in 64 consecutive patients with 64 peripheral adenocarcinomas of 20 mm or less (mean, 13 mm), including 36 women and 28 men with a mean age of 64 years were analyzed and correlated with survival of the patients using Kaplan-Meier method and stepwise Cox proportional hazards modeling. Follow-up periods of the patients ranged from 6 to 45 months (mean, 22 months). Tumors were classified into six subtypes (types A-F) according to tumor growth patterns defined by Noguchi et al. RESULTS: Six (9%) of the 64 patients died of lung cancer. In univariate analyses, a significant difference was noted for lesion size (P=0.043), the percentage of GGO areas (P=0.005), and tumor subtypes (P=0.006). Lesion size of <15 mm (n=35), a lesion with GGO areas of >57% (n=36), and type A (n=16) or type B adenocarcinomas (n=16) indicated a significantly better survival. In multivariate analyses using these three parameters as independent variables, the percentage of GGO areas was the only significant independent factor for survival (P=0.044, relative risk=0.95). CONCLUSION: GGO areas measured on HRCT may have an independent prognostic significance of small adenocarcinomas of the lung.

Discrimination of subtypes of small adenocarcinoma in the lung with thin-section CT.

We studied the usefulness of thin-section CT in discriminating two categories of adenocarcinoma in the lung. Thin-section CT findings, such as, lesion size, ground-glass opacity (GGO) areas of lesion and presence or absence of lobulation, coarse spiculation, air bronchogram, small air space, or pleural tag of lesion in 62 consecutive patients with 62 adenocarcinomas (35 type A or B tumors (Noguchi's classification) and 27 type C tumors) of < or =20 mm, including 36 women and 26 men with a mean age of 64 years were analyzed. We performed stepwise logistic modeling using all the CT findings as independent variables to estimate the significant factors for discriminating type C from type A or B tumor. Lesion size in type C tumors was significantly (P<0.001) greater than that in type A or B tumors. GGO areas in type C tumors were significantly (P<0.001) smaller than that in type A or B tumors. The prevalence of coarse spiculation, air bronchogram, and pleural tag in type C tumors was significantly greater (P=0.001, 0.010, and <0.001, respectively) than that in type A or B tumors. Logistic modeling revealed that the GGO area was the only significant factor for discriminating two categories (P<0.001). Using the percentage of GGO areas for predicting type C tumor, 40% or less showed the highest accuracy of 85% with 70% sensitivity and 97% specificity. GGO areas of 30% or less had no false-positive diagnosis (100% specificity) with 81% accuracy but its sensitivity was low (56%). Thin-section CT was useful in discriminating two categories of adenocarcinoma in the lung.