PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9830667

[Morphologic image processing operators: reduction of partial volume effects for improved 3D visualization of CT data].

J Beier·R C Bittner·N Hosten·J Tröger·R Felix
View original source ↗Export metadata ↓

Abstract

AIM: The quality of segmentation and three-dimensional reconstruction of anatomical structures in tomographic slices is often impaired by disturbances due to partial volume effects (PVE). The potential for artefact reduction by use of the morphological image processing operators (MO) erosion and dilation is investigated. DESIGN: The CT examinations of 31 patients with pathological alterations in lung or brain were segmented using automatic region growing and the MO were applied in a different number of iterations. The processed regions were 3D-reconstructed (shaded surface display, MIP, volume rendering) and the occurrence of PVE-related artefacts using the signal-to-background ratio (SBR) prior to and after MO application was compared. RESULTS: For all patients under review, the artefacts caused by PVE were significantly reduced by erosion (lung: mean SBRpre = 1.67, SBRpost = 4.83; brain: SBRpre = 1.06, SBRpost = 1.29) even with only a small number of iterations. Region dilation was applied to integrate further structures (e.g. at tumor borders) into a configurable neighbourhood for segmentation and quantitative analysis. CONCLUSIONS: The MO represent an efficient approach for the reduction of PVE artefacts in 3D-CT reconstructions and allow optimized visualization of individual objects.

Explore related subjects

DensitometryHumansImage Interpretation, Computer-AssistedTomography, X-Ray ComputedEnglish AbstractJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Beier, R C Bittner, N Hosten, J Tröger, R Felix. 1998. [Morphologic image processing operators: reduction of partial volume effects for improved 3D visualization of CT data].. https://doi.org/10.1007/s001170050435

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Component volumes of unsaturated phosphatidylcholines in fluid bilayers: a densitometric study.

The specific volumes of six 1,2-diacylphosphatidylcholines with monounsaturated acyl chains (diCn:1PC, n=14-24 is the even number of acyl chain carbons) in fluid bilayers in multilamellar vesicles dispersed in H(2)O were determined by the vibrating tube densitometry as a function of temperature. From the data obtained with diCn:1PC (n=14-22) vesicles in combination with the densitometric data from Tristram-Nagle et al. [Tristram-Nagle, S., Petrache, H.I., Nagle, J.F., 1998. Structure and interactions of fully hydrated dioleoylphosphatidylcholine bilayers. Biophys. J. 75, 917-925.] and Koenig and Gawrisch [Koenig, B.W., Gawrisch, K., 2005. Specific volumes of unsaturated phosphatidylcholines in the liquid crystalline lamellar phase. Biochim. Biophys. Acta 1715, 65-70.], the component volumes of phosphatidylcholines in fully hydrated fluid bilayers at 30 degrees C were obtained. The volume of the acyl chain CH and CH(2) group is V(CH)=22.30 A(3) and V(CH2) =A(3), respectively. The volume of the headgroup including the glyceryl and acyl carbonyls, V(H), and the ratio of acyl chain methyl and methylene group volumes, r=V(CH3):V(CH2) are linearly interdependent: V(H)=a-br, where a=434.41 A(3) and b=-55.36 A(3) at 30 degrees C. From the temperature dependencies of component volumes, their isobaric thermal expansivities (alpha(X)=V(X)(-1)(partial differential V(X)/ partial differential T) where X=CH(2), CH, or H were calculated: alpha(CH2)=118.4x10(-5)K(-1), alpha(CH)=71.0x10(-5)K(-1), alpha(H)=7.9x10(-5)K(-1) (for r=2) and alpha(H)=9.6x10(-5)K(-1) (for r=1.9). The specific volume of diC24:1PC changes at the main gel-fluid phase transition temperature, t(m)=26.7 degrees C, by 0.0621 ml/g, its specific volume is 0.9561 and 1.02634 ml/g at 20 and 30 degrees C, respectively, and its isobaric thermal expansivity alpha=68.7x10(-5) and 109.2x10(-5)K(-1) below and above t(m), respectively. The component volumes and thermal expansivities obtained can be used for the interpretation of X-ray and neutron scattering and diffraction experiments and for the guiding and testing molecular dynamics simulations of phosphatidylcholine bilayers in the fluid state.

Densitometry↗
PubMed2006

[The diagnostics of osteoporosis in the evaluation of fracture risk].

Osteoporosis is a metabolic bone disease affecting a large portion of the population. In the osteoporotic process, organic and inorganic components on the bone are reduced, bone quality is deteriorated, strength of bone tissue is diminished, thus fracture risk is increasing as a consequence. Knowledge of the disease is essential for all physicians due to the frequency of this disorder. The aim of osteoporosis diagnostics is to discover the disease, to differentiate from other similar disorders, and to estimate fracture risk in order to introduce effective treatment. To carry out this task effectively, beside the proper evaluation of the patient's history, physical examination, osteodensitometry, X-ray and laboratory tests, some new factors revealed recently known to influence fracture risk should also be considered. The purpose of the present review is to summarize most recent data related to the diagnostics of osteoporosis from the view of the everyday practice.

Densitometry↗
PubMed2006

Portal verification of high-energy electron beams using their photon contamination by film-cassette systems.

BACKGROUND AND PURPOSE: Though electron beams are widely used in radiotherapy, their verification is not well established in clinical practice. The present study compares the suitability of several sensitive film-cassette systems for electron-portal verification by contaminating photons. MATERIAL AND METHODS: The characteristics of the optical density curves of film-cassette combinations were determined by exposing them to the bremsstrahlung contamination of a variety of electron beams. Using a Las-Vegas Phantom the spatial low-contrast resolution of the combinations was investigated. The absorbed dose rates due to the contaminant photons were measured for different geometric conditions. RESULTS: Suitable film-cassette combinations were found for portal verification of all usual electron energies. The best image quality was obtained using the EC film and the EC-L cassettes. For electron energies higher than 6 MeV some film-cassette combinations are suitable to verify abutted electron and photon portals using the same film sheet. CONCLUSION: The verification of electron portals and of abutted electron-photon portals can be performed by sensitive film-cassette systems with an image quality comparable to photon-beam verification.

Densitometry↗