title: Relationship between CT findings of pulmonary tuberculosis and the number of acid-fast bacilli on sputum smears.
abstract: OBJECTIVE
  To investigate the relationship between computed tomography (CT) findings in patients with active pulmonary tuberculosis (PTB) and the number of acid-fast bacilli (AFB) on sputum smears.
  
  
  METHODS
  We reviewed CT scans of 173 patients with active PTB. The patients were divided into groups according to the number of AFB on sputum smears as follows: A, negative (n = 40); B, doubtful (n = 21); C, + (n = 34); and D, ++ or greater (n = 78). The presence or absence and the number of lobes that included micronodules, nodules, consolidation and cavitation, the number of cavities and the maximum diameter of the cavity lumen were noted.
  
  
  RESULTS
  The frequency of micronodules and nodules did not significantly differ among the four groups. In contrast, the frequency of consolidation and cavitation increased with the number of AFB (P < .0001). Differences in the number of lobes involving micronodules, nodules, consolidation and cavitation were significant between Group D and the other groups (P < .0001), but not between Groups A or B and C. The number and maximum size of cavities significantly differed between Group D and the other groups (P < .0001).
  
  
  CONCLUSIONS
  CT findings correlated with the number of AFB in sputum smears to some extent. However, CT findings do not reliably discriminate between smear-negative patients and those with very few AFB excreting smear-positive patients.
authors.affiliation: Department of Radiology, Teikyo University School of Medicine, Ichihara Hospital 3426-3, Anesaki, Ichihara, Chiba 299-0111, Japan. shinma@d9.dion.ne.jp
authors.forename: Shin
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Hideki
authors.initials: H
authors.lastname: Shima
authors.forename: Kiminori
authors.initials: K
authors.lastname: Suzuki
authors.forename: Akimitsu
authors.initials: A
authors.lastname: Shimura
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamagishi
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013183:Sputum / Q000382:microbiology*; D014057:Tomography, X-Ray Computed; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000000981:diagnostic imaging*