title: Pulmonary functional imaging: qualitative comparison of Fourier decomposition MR imaging with SPECT/CT in porcine lung.
abstract: OBJECTIVE
  To compare unenhanced lung ventilation-weighted (VW) and perfusion-weighted (QW) imaging based on Fourier decomposition (FD) magnetic resonance (MR) imaging with the clinical reference standard single photon emission computed tomography (SPECT)/computed tomography (CT) in an animal experiment.
  
  
  METHODS
  The study was approved by the local animal care committee. Lung ventilation and perfusion was assessed in seven anesthetized pigs by using a 1.5-T MR imager and SPECT/CT. For time-resolved FD MR imaging, sets of lung images were acquired by using an untriggered two-dimensional balanced steady-state free precession sequence (repetition time, 1.9 msec; echo time, 0.8 msec; acquisition time per image, 118 msec; acquisition rate, 3.33 images per second; flip angle, 75°; section thickness, 12 mm; matrix, 128 × 128). Breathing displacement was corrected with nonrigid image registration. Parenchymal signal intensity was analyzed pixelwise with FD to separate periodic changes of proton density induced by respiration and periodic changes of blood flow. Spectral lines representing respiratory and cardiac frequencies were integrated to calculate VW and QW images. Ventilation and perfusion SPECT was performed after inhalation of dispersed technetium 99m ((99m)Tc) and injection of (99m)Tc-labeled macroaggregated albumin. FD MR imaging and SPECT data were independently analyzed by two physicians in consensus. A regional statistical analysis of homogeneity and pathologic signal changes was performed.
  
  
  RESULTS
  Images acquired in healthy animals by using FD MR imaging and SPECT showed a homogeneous distribution of VW and QW imaging and pulmonary ventilation and perfusion, respectively. The gravitation-dependent signal distribution of ventilation and perfusion in all animals was similarly observed at FD MR imaging and SPECT. Incidental ventilation and perfusion defects were identically visualized by using both modalities.
  
  
  CONCLUSIONS
  This animal experiment demonstrated qualitative agreement in the assessment of regional lung ventilation and perfusion between contrast media-free and radiation-free FD MR imaging and conventional SPECT/CT.
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. g.bauman@dkfz.de
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Bauman
authors.forename: Ulf
authors.initials: U
authors.lastname: Lützen
authors.forename: Mathias
authors.initials: M
authors.lastname: Ullrich
authors.forename: Thomas
authors.initials: T
authors.lastname: Gaass
authors.forename: Julien
authors.initials: J
authors.lastname: Dinkel
authors.forename: Gunnar
authors.initials: G
authors.lastname: Elke
authors.forename: Patrick
authors.initials: P
authors.lastname: Meybohm
authors.forename: Inéz
authors.initials: I
authors.lastname: Frerichs
authors.forename: Beata
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Jan
authors.initials: J
authors.lastname: Borggrefe
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Knuth
authors.forename: Jasper
authors.initials: J
authors.lastname: Schupp
authors.forename: Hermann
authors.initials: H
authors.lastname: Prüm
authors.forename: Monika
authors.initials: M
authors.lastname: Eichinger
authors.forename: Michael
authors.initials: M
authors.lastname: Puderbach
authors.forename: Jürgen
authors.initials: J
authors.lastname: Biederer
authors.forename: Christian
authors.initials: C
authors.lastname: Hintze
mesh_terms: D000818:Animals; D005260:Female; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D013670:Sodium Pertechnetate Tc 99m; D018709:Statistics, Nonparametric; D013552:Swine; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D013668:Technetium Tc 99m Aggregated Albumin; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m