Analysis of contrast-enhanced dynamic MR images of the lung.
Recent studies have demonstrated the potential of dynamic contrast-enhanced magnetic resonance imaging (MRI) describing pulmonary perfusion. However, breathing motion, susceptibility artifacts, and a low signal-to-noise ratio (SNR) make automatic pixel-by-pixel analysis difficult. In the present work, we propose a novel method to compensate for breathing motion. In order to test the feasibility of this method, we enrolled 53 patients with pulmonary embolism (N = 24), chronic obstructive pulmonary disease (COPD) (N = 14), and acute pneumonia (N = 15). A crucial part of the method, an automatic diaphragm detection algorithm, was evaluated in all 53 patients by two independent observers. The accuracy of the method to detect the diaphragm showed a success rate of 92%. Furthermore, a Bayesian noise reduction technique was implemented and tested. This technique significantly reduced the noise level without removing important clinical information. In conclusion, the combination of a motion correction method and a Bayesian noise reduction method offered a rapid, semiautomatic pixel-by-pixel analysis of the lungs with great potential for research and clinical use.
Department of Anesthesia and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. geirt@mr.ntnu.no
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Torheim
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Amundsen
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Rinck
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Haraldseth
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Sebastiani
D000465:Algorithms; D001499:Bayes Theorem; D003287:Contrast Media / Q000008:administration & dosage; D003964:Diaphragm / Q000502:physiology*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008171:Lung Diseases / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA