Visibility of small peripheral lung cancers on chest radiographs: influence of densitometric parameters, CT values and tumour type.

The purpose of this study was to determine the effects of tumour density and tumour type on the visibility of small peripheral lung cancers on chest radiographs. We retrospectively evaluated the visibility of 63 small (< or = 20 mm) peripheral lung cancers on chest radiographs. 48 (76%) were detected in our low dose CT screening for lung cancer and 15 (24%) in routine clinical examination. Analysis was based on tumour optical contrast, gradient at the tumour margin, CT values and tumour type. There were 31 (49%) visible cancers and 32 (51%) invisible cancers on chest radiographs. Visible tumours had an optical density of 0.1-0.3 OD and a gradient of 0.03-0.11 OD mm-1. The mean size of visible tumour (14.3 mm) was larger than that of invisible tumour (11.1 mm; p < 0.001). The mean CT value (-140 HU) of visible tumour was higher than that of invisible tumour (-490 HU; p < 0.001). The detection rates of adenocarcinomas with lepidic growth (0% for type A, 29% for type B and 68% for type C) were less than those with hilic growth (100% for types D-F). All squamous and small cell carcinomas with hilic growth were visible on chest radiographs, but the numbers of each were small. In summary, tumour type influenced the contrast, gradient, CT values and margin of the tumour. Small adenocarcinomas with a lepidic tumour growth were less well seen on chest radiographs compared with small lung cancers with hilic tumour growth.

[1]  G Revesz,et al.  Conspicuity and uncertainty in the radiographic detection of lesions. , 1985, Radiology.

[2]  H. Ohmatsu,et al.  Peripheral lung cancer: screening and detection with low-dose spiral CT versus radiography. , 1996, Radiology.

[3]  F M Charbonnier,et al.  Depth resolution: a mechanism by which high kilovoltage improves visibility in chest films. , 1975, Radiology.

[4]  J. Austin,et al.  Missed bronchogenic carcinoma: radiographic findings in 27 patients with a potentially resectable lesion evident in retrospect. , 1992, Radiology.

[5]  T M Yelbuz,et al.  Pulmonary nodules: experimental and clinical studies at low-dose CT. , 1999, Radiology.

[6]  Setsuo Hirohashi,et al.  Small adenocarcinoma of the lung. Histologic characteristics and prognosis , 1995 .

[7]  H L Kundel,et al.  Densitometric measurements of lung nodules on chest radiographs. , 1981, Investigative radiology.

[8]  B. Raasch,et al.  Pathways of tumor spread through the lung: radiologic correlations with anatomy and pathology. , 1982, Radiology.

[9]  H L Kundel,et al.  Contrast gradient and the detection of lung nodules. , 1979, Investigative radiology.

[10]  O. Miettinen,et al.  Early Lung Cancer Action Project: overall design and findings from baseline screening , 1999, The Lancet.

[11]  J. V. van Engelshoven,et al.  Miss rate of lung cancer on the chest radiograph in clinical practice. , 1999, Chest.

[12]  C. White,et al.  Missed lung cancer on chest radiography and computed tomography: imaging and medicolegal issues. , 1999, Journal of thoracic imaging.

[13]  C A Kelsey,et al.  Factors affecting perception of pulmonary lesions. , 1983, Radiologic clinics of North America.

[14]  Feng Li,et al.  Mass screening for lung cancer with mobile spiral computed tomography scanner , 1998, The Lancet.

[15]  J. Woodring,et al.  Pitfalls in the radiologic diagnosis of lung cancer. , 1990, AJR. American journal of roentgenology.

[16]  F. Li,et al.  Small peripheral carcinomas of the lung: thin-section CT and pathologic correlation , 1999, European Radiology.