title: Comparison between high-resolution CT and MRI using a very short echo time in patients with cystic fibrosis with extra focus on mosaic attenuation.
abstract: BACKGROUND
  It would be beneficial to establish pulmonary MRI as a complementary approach to CT for direct visualization of mosaic perfusion, bullae, and emphysema in patients with cystic fibrosis.
  
  
  OBJECTIVE
  The purpose of this study was to compare both modalities, CT and MRI, using the Helbich-Bhalla score with a special focus on reliable detection of a mosaic pattern.
  
  
  METHODS
  Out of 51 patients examined by MRI on a 1.5-Tesla system during a period of 2 years, 19 patients were scheduled for additional low-dose CT in a clinical context. The MRI protocol comprised a gradient echo (GRE) sequence with a very short echo time (TE = 0.8 ms) in inspiration and expiration, a 3-D GRE sequence in breath hold, and a fast spin echo sequence with respiration and ECG triggering. MDCT was carried out in inspiration and adapted to body weight using 100 or 120 kV, 30-60 mA, 1- and 3-mm slice thicknesses, as well as low and high kernels. Additionally incremental slices in 3 positions were recorded in expiration for distinct detection of air trapping. CT and MRI analyses were performed by two radiologic readers in consensus unaware of the clinical parameters. The Helbich-Bhalla score of both examinations was correlated. Mean difference and accordance were assessed in each category.
  
  
  RESULTS
  There was a strong correlation between CT and MRI (R = 0.87, p < 0.01). The mean Helbich-Bhalla score for CT was 12.2 (range 1-18) and for MRI it was 11.7 (range 2-19). The mean difference was 0.5 points. Besides this strong correlation for findings (bronchiectasis, mucus plugging, peribronchial thickening, and consolidation) with a prolonged T2 TE in MRI, we could also state a qualitative agreement of 95-100% in the categories with short T2 and low signal intensity in MRI as emphysema, bullae, and mosaic perfusion.
  
  
  CONCLUSIONS
  These results suggest that in our patient group none of the relevant findings were missed by MR imaging and reading.
authors.affiliation: Section of Experimental Radiology, University of Tübingen, Tübingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Teufel
authors.forename: Dominik
authors.initials: D
authors.lastname: Ketelsen
authors.forename: Sabrina
authors.initials: S
authors.lastname: Fleischer
authors.forename: Petros
authors.initials: P
authors.lastname: Martirosian
authors.forename: Ulrike
authors.initials: U
authors.lastname: Graebler-Mainka
authors.forename: Martin
authors.initials: M
authors.lastname: Stern
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
authors.forename: Juergen F
authors.initials: JF
authors.lastname: Schaefer
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D014057:Tomography, X-Ray Computed; D055815:Young Adult