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ABSTRACT: Purpose:To propose and test the feasibility of a novel method for quantifying 3D regional pulmonary kinematics from hyperpolarized helium-3 tagged MRI in human subjects using a tailored image processing pipeline and a recently developed nonrigid registration framework.Materials and Methods:Following image acquisition, inspiratory and expiratory tagged 3He magnetic resonance (MR) images were preprocessed using various image filtering techniques to enhance the tag surfaces. Segmentation of the three orthogonal sets of tag planes in each lung produced distinct point-set representations of the tag surfaces. Using these labeled point-sets, deformation fields and corresponding strain maps were obtained via nonrigid point-set registration. Kinematic analysis was performed on three volunteers.Results:Tag lines in inspiratory and expiratory images were coregistered producing a continuous 3D correspondence mapping. Average displacement and directional strains were calculated in three subjects in the inferior, mid, and superior portions of the right and left lungs. As expected, the predominant direction of displacements with expiration is from inferior to superior.Conclusion:Kinematic quantitation of pulmonary motion using tagged 3He MRI is feasible using the applied image preprocessing filtering techniques and nonrigid point-set registration. Potential benefits from regional pulmonary kinematic quantitation include the facilitation of diagnosis and local assessment of disease progression. J. Magn. Reson. Imaging 2010;31:1236–1241. © 2010 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 04/2010; 31(5):1236 - 1241. · 2.70 Impact Factor
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ABSTRACT: PurposeTo investigate short- and long-time-scale 3He diffusion in asthma.Materials and MethodsA hybrid MRI sequence was developed to obtain coregistered short- and long-time-scale apparent diffusion coefficient (ADC) maps during a single breath-hold. The study groups were: asthma (n = 14); healthy (n = 14); chronic obstructive pulmonary disease (COPD) (n = 9). Correlations were made between mean-ADC and %ADC-abn (abnormal) (%pixels with ADC > mean +2 SD of healthy) at both time scales and spirometry. Sensitivities were determined using receiver operating characteristic (ROC) analysis.ResultsFor asthmatics, the short- and long-time-scale group-mean ADCs were 0.254 ± 0.032 cm2/s and 0.0237 ± 0.0055 cm2/s, respectively, representing a 9% and 27% (P = 0.038 and P = 0.005) increase compared to the healthy group. The group-mean %ADC-abn were 6.4% ± 3.7% and 17.5% ± 14.2%, representing a 107% and 272% (P = 0.004 and P = 0.006) increase. For COPD much greater elevations were observed. %ADC-abn provided better discrimination than mean-ADC between asthmatic and healthy subjects. In asthmatics ADC did not correlate with spirometry.Conclusion
With long-time scale 3He diffusion magnetic resonance imaging (MRI) changes in lung microstructure were detected in asthma that more conspicuous regionally than at the short time scale. The hybrid diffusion method is a novel means of identifying small airway disease. J. Magn. Reson. Imaging 2008;28:80–88. © 2008 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 06/2008; 28(1):80 - 88. · 2.70 Impact Factor
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ABSTRACT: PurposeTo determine whether hyperpolarized helium-3 (HHe) diffusion MR can detect the expected enlargement of alveoli that occurs with lung growth during childhood.Materials and MethodsA total of 29 normal subjects aged four to 30 years underwent HHe diffusion MR imaging with the b-value pair 0, 1.6 second/cm2. A second acquisition during a separate breathhold was performed using the b-value pair 0, 4 second/cm2 to evaluate the dependence on b-value. The mean apparent diffusion coefficient (ADC) and lung volume for each acquisition and each subject was determined.ResultsSubjects as young as four years of age were able to cooperate with the imaging procedure. The mean ADC increased with increasing subject age (r = 0.8; P < 0.001), with a 55% increase in mean ADC from the youngest to oldest subject. Lung volumes measured on MR were highly repeatable for the two HHe MR acquisitions (r = 0.980, P < 0.001). The mean ADC values measured with the two different b-value pairs were highly correlated (r = 0.975; P < 0.001), but the higher b-value pair resulted in slightly lower mean ADCs (P < 0.001).ConclusionHHe diffusion MR appears to detect the expected increase in alveolar size during childhood, and thus HHe MR may be a noninvasive method to assess development of the lung microstructure. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 11/2006; 24(6):1277 - 1283. · 2.70 Impact Factor
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Talissa A. Altes MD,
Patrick L. Powers MD,
Jack Knight-Scott PhD,
Gary Rakes MD,
Thomas A.E. Platts-Mills MD, Eduard E. de Lange MD,
Bennett A. Alford MD,
John P. Mugler III PhD,
James R. Brookeman PhD,
Talissa A. Altes,
Patrick L. Powers,
Jack Knight‐Scott,
Gary Rakes,
Thomas A.E. Platts‐Mills,
Eduard E. de Lange,
Bennett A. Alford,
John P. Mugler III,
James R. Brookeman
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ABSTRACT: Asthma is a disease characterized by chronic inflammation and reversible obstruction of the small airways resulting in impaired pulmonary ventilation. Hyperpolarized 3He magnetic resonance (MR) lung imaging is a new technology that provides a detailed image of lung ventilation. Hyperpolarized 3He lung imaging was performed in 10 asthmatics and 10 healthy subjects. Seven asthmatics had ventilation defects distributed throughout the lungs compared with none of the normal subjects. These ventilation defects were more numerous and larger in the two symptomatic asthmatics who had abnormal spirometry. Ventilation defects studied over time demonstrated no change in appearance over 30–60 minutes. One asthmatic subject was studied twice in a three-week period and had ventilation defects which resolved and appeared in that time. This same subject was studied before and after bronchodilator therapy, and all ventilation defects resolved after therapy. Hyperpolarized 3He lung imaging can detect the small, reversible ventilation defects that characterize asthma. The ability to visualize lung ventilation offers a direct method of assessing asthmatics and their response to therapy. J. Magn. Reson. Imaging 2001;13:378–384. © 2001 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 02/2001; 13(3):378 - 384. · 2.70 Impact Factor
