title: Development of low-dose protocols for thin-section CT assessment of cystic fibrosis in pediatric patients.
abstract: OBJECTIVE
  To develop low-dose thin-section computed tomographic (CT) protocols for assessment of cystic fibrosis (CF) in pediatric patients and determine the clinical usefulness thereof compared with chest radiography.
  
  
  METHODS
  After institutional review board approval and informed consent from patients or guardians were obtained, 14 patients with CF and 11 patients without CF (16 male, nine female; mean age, 12.6 years ± 5.4 [standard deviation]; range, 3.5-25 years) who underwent imaging for clinical reasons underwent low-dose thin-section CT. Sections 1 mm thick (protocol A) were used in 10 patients, and sections 0.5 mm thick (protocol B) were used in 15 patients at six levels at 120 kVp and 30-50 mA. Image quality and diagnostic acceptability were scored qualitatively and quantitatively by two radiologists who also quantified disease severity at thin-section CT and chest radiography. Effective doses were calculated by using a CT dosimetry calculator.
  
  
  RESULTS
  Low-dose thin-section CT was performed with mean effective doses of 0.19 mSv ± 0.03 for protocol A and 0.14 mSv ± 0.04 for protocol B (P < .005). Diagnostic acceptability and depiction of bronchovascular structures at lung window settings were graded as almost excellent for both protocols, but protocol B was inferior to protocol A for mediastinal assessment (P < .02). Patients with CF had moderate lung disease with a mean Bhalla score of 9.2 ± 5.3 (range, 0-19), compared with that of patients without CF (1.1 ± 1.4; P < .001). There was excellent correlation between thin-section CT and chest radiography (r = 0.88-0.92; P < .001).
  
  
  CONCLUSIONS
  Low-dose thin-section CT can be performed at lower effective doses than can standard CT, approaching those of chest radiography. Low-dose thin-section CT could be appropriate for evaluating bronchiectasis in pediatric patients, yielding appropriate information about lung parenchyma and bronchovascular structures.
authors.affiliation: Department of Radiology, University College Cork and Cork University Hospital, Wilton, Cork 1111, Ireland.
authors.forename: Owen J
authors.initials: OJ
authors.lastname: O'Connor
authors.forename: Moya
authors.initials: M
authors.lastname: Vandeleur
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: McGarrigle
authors.forename: Niamh
authors.initials: N
authors.lastname: Moore
authors.forename: Sebastian R
authors.initials: SR
authors.lastname: McWilliams
authors.forename: Sean E
authors.initials: SE
authors.lastname: McSweeney
authors.forename: Michael
authors.initials: M
authors.lastname: O'Neill
authors.forename: Muireann
authors.initials: M
authors.lastname: Ni Chroinin
authors.forename: Michael M
authors.initials: MM
authors.lastname: Maher
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011829:Radiation Dosage; D013902:Radiography, Thoracic; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult