title: Prevalence and imaging characteristics of detectable tonsilloliths on 482 pairs of consecutive CT and panoramic radiographs.
abstract: BACKGROUND
  Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs.
  
  
  METHODS
  482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed.
  
  
  RESULTS
  The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333).
  
  
  CONCLUSIONS
  The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.
authors.affiliation: Division of Oral and Maxillofacial Radiology, Kyushu Dental University, Kitakyushu, Japan. rad-mori@kyu-dent.ac.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Oda
authors.forename: Shinji
authors.initials: S
authors.lastname: Kito
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Tanaka
authors.forename: Ikuko
authors.initials: I
authors.lastname: Nishida
authors.forename: Shuji
authors.initials: S
authors.lastname: Awano
authors.forename: Yuko
authors.initials: Y
authors.lastname: Fujita
authors.forename: Katsura
authors.initials: K
authors.lastname: Saeki
authors.forename: Shinobu
authors.initials: S
authors.lastname: Matsumoto-Takeda
authors.forename: Nao
authors.initials: N
authors.lastname: Wakasugi-Sato
authors.forename: Manabu
authors.initials: M
authors.lastname: Habu
authors.forename: Shinya
authors.initials: S
authors.lastname: Kokuryo
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kodama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneuji
authors.forename: Daigo
authors.initials: D
authors.lastname: Yoshiga
authors.forename: Ikuya
authors.initials: I
authors.lastname: Miyamoto
authors.forename: Shun
authors.initials: S
authors.lastname: Nishimura
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Kenshi
authors.initials: K
authors.lastname: Maki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tominaga
authors.forename: Izumi
authors.initials: I
authors.lastname: Yoshioka
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ansai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Morimoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002137:Calculi / Q000000981:diagnostic imaging / Q000473:pathology; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D020347:Lithiasis / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014066:Palatine Tonsil / Q000000981:diagnostic imaging* / Q000473:pathology; D010608:Pharyngeal Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D011862:Radiography, Panoramic; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed; D055815:Young Adult