Measurement of Lung Density by Computed Tomography

Oh, Wegener; Koeppe, P.; Oeser, H

doi:10.1097/00004728-197807000-00003

Cited by 96 publications

(36 citation statements)

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“…CT has been used previously in studies of lung density.15)-18) It has been used to detect abnormalities more readily than other radiological methods in diseases which may decrease lung density, such as pulmonary emphysema, or increase fluid accumulations, such as pulmonary congestion.15),16),21) The measurement of lung density by the CT method is little influenced by the thorax, rib and soft tissue, and reflects the changes of fluid content in the thorax. 16,20) In the evaluation of cardiopulmonary function, the influence of respiration on these factors cannot be ignored.16) Lung densities at repeated maximum inspiration showed high reproducibility. With regard to the influence of body position, the density of the anterior and posterior portions of the lung reverses by changing from supine to prone position.15),20),21) This is explained by the differences in blood flow due to gravity.17) Taking these factors into consideration, we performed the CT examinations in the supine position at maximum inspiration.…”

Section: Discussionmentioning

confidence: 99%

Measurement of lung density in congestive heart failure by computed tomography.

et al. 1984

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SUMMARYThe computed tomography (CT) number within the region of interest (ROI) was used as a parameter to assess lung density in patients with congestive heart failure. Thirty-eight patients with valvular heart disease (VHD) and 34 patients with ischemic heart disease (IHD) were studied. Based on the New York Heart Association (NYHA) classification, 24 VHD patients were in class I or II (VHD I-II) and the other 14 were in NYHA class III or IV (VHD III-IV).Eighteen patients with IHD were in NYHA class I or II (IHD I-II) and 16 were in class III or IV (IHD III-IV). The CT number was measured bilaterally at the upper, middle and lower levels of the chest and compared with the corresponding values in 21 normal subjects (Group N). In a preliminary study on Group N, the CT numbers were insensitive to the size of the ROI, but were closely related to its location.In clinical applications, the mean values of the CT numbers in all six lung fields increased in the order of IHD I-II, to VHD I-II, IHD III-IV and VHD III-IV.Except for patients in IHD I-II, they were significantly larger than in Group N. The relationship between the CT number and the systolic and mean pulmonary arterial pressures and the pulmonary capillary wedge pressure were evaluated in 36 patients. Significant correlations were obtained in all six lung fields (r=0.65-0.78, p<0.001). The results suggest that measurement of lung density by CT is useful for the quantitative evaluation of the severity of disease in patients with congestive heart failure.

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Section: Discussionmentioning

confidence: 99%

Measurement of lung density in congestive heart failure by computed tomography.

et al. 1984

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“…Any segmentation task has to take into account the co-existence within the same slice of quite different densities corresponding to vascular, interstitial and air portions associated either with alveolar space and/or bronchi. In 4 , for instance, several examples are presented concerning the variability of mean densities of small regions of interest defined within the lung field. The reproducibility of lung densitometry is still remarkably influenced by the respiratory cycle.…”

Section: Methodologies For Segmentation Of Pulmonary Tomogramsmentioning

confidence: 99%

“…The reproducibility of lung densitometry is still remarkably influenced by the respiratory cycle. Also in 4 , it is mentioned that maximum inspiration is the functional condition that achieves best reproducibility for densitometric purposes. Fortunately, current scanner technology ensures that data acquisition for the whole pulmonary volume can now be accomplished in a short period of time so, normally, a cooperative patient attitude can be expected.…”

Section: Methodologies For Segmentation Of Pulmonary Tomogramsmentioning

confidence: 99%

<title>Fast pulmonary contour extraction in x-ray CT images: a methodology and quality assessment</title>

Silva

Santos

et al. 2001

SPIE Proceedings

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Segmentation of thoracic X-Ray Computed Tomography images is a mandatory pre-processing step in many automated or semi-automated analysis tasks such us region identification, densitometric analysis, or even for 3D visualization purposes when a stack of slices has to be prepared for surface or volume rendering. In this work, we present a fully automated and fast method for pulmonary contour extraction and region identification. Our method combines adaptive intensity discrimination, geometrical feature estimation and morphological processing resulting into a fast and flexible algorithm. A complementary but not less important objective of this work consisted on a quality assessment study of the developed contour detection technique. The automatically extracted contours were statistically compared to manually drawn pulmonary outlines provided by two radiologists. Exploratory data analysis and non-parametric statistical tests were performed on the results obtained using several figures of merit. Results indicate that, besides a strong consistence among all the quality indexes, there is a wider inter-observer variability concerning both radiologists than the variability of our algorithm when compared to each one of the radiologists. As an overall conclusion we claim that the consistence and accuracy of our detection method is more than acceptable for most of the quantitative requirements mentioned by the radiologists.

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“…Lung volume is the main confounder and the physiological variable that is probably most pertinent to the reproducibility of densitometry in long-term studies. Gross lung density can vary by as much as 80-100 HU from full inspiration to end expiration [346,347].…”

Section: Outcomes For Copd Pharmacological Trialsmentioning

confidence: 99%