title: MRI of the lung using the PROPELLER technique: Artifact reduction, better image quality and improved nodule detection.
abstract: OBJECTIVE
  To evaluate the benefit of the PROPELLER technique (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction, MultiVane, MV) for MR imaging of the lung.
  
  
  METHODS
  30 Participants of a lung cancer screening program were recruited for the comparison of T2-MV and T2-Fast Spin Echo (FSE) sequences at 1.5T. Two readers evaluated artifacts, image quality, and pulmonary lesions. Artifacts and image quality were rated using a four-point scale. Lesion detection was correlated to low-dose computed tomography (CT). Wilcoxon rank-test for ratings of artifacts and image quality, sensitivity and specificity values for lesion detection, and Cohen's kappa for inter-rater agreement were used.
  
  
  RESULTS
  The MV sequence showed less pulsation and motion artifacts, and higher image quality (p=0.001 for R1, p=0.002 for R2) than FSE (p<0.001 for both readers, R1 and R2). Inter-rater agreement was excellent for lesion detection (0.84-0.95) and good to excellent for artifacts and image quality (0.66-0.84). 17 patients had lesions <8mm, and 7 had lesions >8mm as seen on CT. For R1 and R2, the MV sequence allowed for higher detection rates of pulmonary lesions <8mm with a sensitivity of 56% (R1) and 59% (R2); the FSE sequence achieved 50% (R1) and 53% (R2). Specificity was also higher for MV with 94% (R1) and 83% (R2) compared to 78% (R1) and 76% (R2). Lesions >8mm were detected with a sensitivity of 100% by both readers on both MV and FSE images. For both readers, specificity for larger lesions was higher on MV images with 100% compared to 96%.
  
  
  CONCLUSIONS
  The superior image quality and the very robust artifact reduction make MV a promising technique for MRI of the lung compared to FSE, especially since it is not requiring breathholds. Moreover, MV allows for improved lesion detection.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany. Electronic address: michael.meier@ukb.uni-bonn.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Meier-Schroers
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany. Electronic address: guido.kukuk@ukb.uni-bonn.de.
authors.forename: Guido
authors.initials: G
authors.lastname: Kukuk
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany. Electronic address: rami.homsi@ukb.uni-bonn.de.
authors.forename: Rami
authors.initials: R
authors.lastname: Homsi
authors.affiliation: Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University of Bonn, Germany. Electronic address: dirk.skowasch@ukb.uni-bonn.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Skowasch
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany. Electronic address: hans.schild@ukb.uni-bonn.de.
authors.forename: Hans Heinz
authors.initials: HH
authors.lastname: Schild
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn, Germany. Electronic address: daniel.thomas@ukb.uni-bonn.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Thomas
mesh_terms: D000368:Aged; D016477:Artifacts; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D015203:Reproducibility of Results; D012119:Respiration; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
keywords: Artifacts; Lung; MRI; MultiVane; PROPELLER