title: Pneumatization Pattern of the Frontal Recess: Relationship of the Anterior-to-Posterior Length of Frontal Isthmus and/or Frontal Recess with the Volume of Agger Nasi Cell.
abstract: OBJECTIVE
  We analyzed the pneumatization pattern of the frontal recess (FR) in a Korean population. We also determined the correlation between the volume of the agger nasi cell (ANC) and the anterior-to-posterior (A-P) length of the frontal isthmus (FI) and FR.
  
  
  METHODS
  Multiplanar paranasal sinus computed tomography (CT) images from 105 patients who underwent endoscopic sinus surgery were reviewed. The prevalence of frontal recess cells (FRCs), thickness of the frontal beak (FB), volume of the ANC, A-P length of the FI, and FR were evaluated.
  
  
  RESULTS
  The ANC was identified in 96% of the patients and frontal cells (FCs) in 32% (FC type 1, 24.2%; type 2, 4.2%; type 3, 3.1%; and type 4, 0%). The prevalences of frontal bullar, suprabullar, supraorbital ethmoidal, and interfrontal sinus septal cells were 10%, 7.8%, 3.6%, and 6.8%, respectively. The A-P lengths of the FR and FI were 10.1+/-3.1 and 8.4+/-2.9 mm, respectively. The thickness of the FB was 7.8+/-1.8 mm and the volume of the ANC averaged 394.1+/-240.5 mm(3). The thickness of the FB did not correlate with the volume of the ANC. In contrast, the A-P length of the FI and FR were positively correlated with the volume of the ANC.
  
  
  CONCLUSIONS
  ANCs and FCs were found in 96% and 32% of the cases in this series. FC type 4 was not seen. What appeared to be FC4 on conventional CT was identified as FBC from reconstructed parasagittal images. A large ANC increased the A-P length of the FI and FR, regardless of the thickness of the FB.
authors.affiliation: Department of ORL-HNS and Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Seong-Soo
authors.initials: SS
authors.lastname: Park
authors.forename: Bit-Na
authors.initials: BN
authors.lastname: Yoon
authors.forename: Kyu-Sup
authors.initials: KS
authors.lastname: Cho
authors.forename: Hwan-Jung
authors.initials: HJ
authors.lastname: Roh