CT of the solitary pulmonary nodule

Abstract

Computed tomography (CT) with thin sections (2-5 mm) was used to assess tissue density in 91 apparently noncalcified pulmonary nodules in 88 patients. The study included 45 primary lung malignancies and 13 metastases proven by subsequent lung biopsy or thoracotomy. There were 33 benign lesions of which 13 were biopsy proven. The other 20 nodules were presumed benign on the basis of serial radiography showing no growth. A representative CT number based on the 32 most dense voxels was calculated for each lesion. For the primary malignancies, the mean representative CT number was 92 H, with a standard deviation of 18 H. The highest representative CT number for any malignant lesion was 147 H. Of the 33 benign lesions, 20 had a representative CT number of 164 H or greater. It is presumed that nodules with representative CT numbers of 164 H are benign, and that diffuse calcification likely accounts for the higher CT number of some benign lesions. CT has proven to be more objective and more sensitive than standard tomography in assessing the density of pulmonary nodules.

Differentiation of Benign and Malignant Solitary Pulmonary Nodule: Literature Review

“…Lobulated contour, signifying uneven growth, is often associated with malignant nodules but can be seen in 25% of benign nodules [14] [15] Although most smoothly marginated nodules are benign but up to 21% of malignant nodules may have this feature [14] A spiculated or irregularly marginated nodule displaying a corona radiata sign indicating neoplastic infiltration and distortion on neighboring tissues is almost certainly a sign of malignancy.…”

“…Siegelman et al (1980) suggested 164 Hounsfield units as threshold above which the nodules are considered benign. It was presumed that diffuse calcification likely accounts for the higher CT numbers of some benign lesions [14]. Xu DM et al (2009) concluded that baseline nodule density and changes in nodule features cannot be used to discriminate between benign and malignant solid indeterminate pulmonary nodules, but an increase in density is suggestive for malignancy and required a shorter follow-up or a biopsy [31].…”

Comparison of Chest Dual-Energy Subtraction Digital Tomosynthesis and Conventional Digital Tomosynthesis for the Detection of Simulated Pulmonary Nodules with Calcifications: Phantom Study

“…In the differentiation of benign and malignant pulmonary masses, 2 radiographic findings give indications of a benign lesion: the presence of calcifications in the mass, and stability of the mass [5][6][7][8][9]. A benign pattern of the calcifications has been considered necessary to exclude malignancy [6,[10][11][12][13].…”

“…In the evaluation of diffusely disseminated pulmonary nodules, identification of diffusely disseminated pulmonary nodules, identification of calcifications in the nodules has been helpful in limiting the differential diagnosis [14]. Conventional radiography and conventional tomography have been used to detect calcifications, but they have been largely replaced by CT [7][8]. However, CT has several inherent problems, including motion artifacts and a variety of reconstruction algorithms used different scanners.…”

Evaluation of a chest phantom for CT nodule densitometry

“…Studies by Siegelman et al [4] first demonstrated a group of benign pulmonary nodules without overt calcification but with CT numbers (attenuation values) above those of neoplasms.…”