title: Collateral ventilation to congenital hyperlucent lung lesions assessed on xenon-enhanced dynamic dual-energy CT: an initial experience.
abstract: OBJECTIVE
  We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT.
  
  
  METHODS
  Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated.
  
  
  RESULTS
  Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv.
  
  
  CONCLUSIONS
  Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea. hwgoo@amc.seoul.kr
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Goo
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Yang
authors.forename: Namkug
authors.initials: N
authors.lastname: Kim
authors.forename: Seung Il
authors.initials: SI
authors.lastname: Park
authors.forename: Dong Kwan
authors.initials: DK
authors.lastname: Kim
authors.forename: Ellen Ai-Rhan
authors.initials: EA
authors.lastname: Kim
mesh_terms: D000280:Administration, Inhalation; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008168:Lung / Q000002:abnormalities / Q000000981:diagnostic imaging*; D019568:Lung, Hyperlucent / Q000151:congenital* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D012123:Pulmonary Ventilation; D014057:Tomography, X-Ray Computed; D014978:Xenon / Q000008:administration & dosage
chemical_list: D014978:Xenon