title: Mediastinal emphysema after esophageal endoscopic submucosal dissection: its prevalence and clinical significance.
abstract: OBJECTIVE
  To assess the prevalence and clinical significance of mediastinal emphysema (ME) after esophageal endoscopic submucosal dissection (ESD).
  
  
  METHODS
  A total of 105 patients in whom assessment of ME was prospectively carried out with multi-detector row computed tomography (MDCT) after esophageal ESD were included in this study. ME was graded as follows: Grade-0, no ME; Grade-I, bubbles around the esophagus; Grade-II, ME around the thoracic aorta; Grade-III, ME extending around the heart or beyond the mediastinum into the neck; and Grade-IV, ME with pneumothorax or subcutaneous emphysema. MDCT grading was compared with the finding of conventional chest X-ray images (CXR) and clinical symptoms.
  
  
  RESULTS
  CXR revealed the presence of ME in 6.6% of the subjects. On MDCT, ME was recognized in 62.9% (Grade-0, 37.1%; I, 46.7%; II, 10.5%; III, 5.7%; and IV, 0%), most (83.8%) being Grade-I or 0. CXR was able to visualize ME of Grade-II or greater. Exposure of the muscularis propria layer and location of the lesion were significant risk factors for development of ME of Grade-II or greater (P = 0.008 and P = 0.03, respectively). The duration of a fever of 37°C or higher was longer and the serum C-reactive protein level was higher in patients with a higher grade of ME.
  
  
  CONCLUSIONS
  MDCT revealed the occurrence of ME in 62.9% of the patients who had undergone esophageal ESD, most of which, however, was clinically silent. Exposure of the muscular layer during ESD and location of the lesion were independent risk factors for the development of ME.
authors.affiliation: Department of Gastroenterology, Sendai City Medical Center, Miyagino-ku, Sendai, Japan. maeda@openhp.or.jp
authors.forename: Yuki
authors.initials: Y
authors.lastname: Maeda
authors.forename: Dai
authors.initials: D
authors.lastname: Hirasawa
authors.forename: Naotaka
authors.initials: N
authors.lastname: Fujita
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Takashi
authors.initials: T
authors.lastname: Obana
authors.forename: Toshiki
authors.initials: T
authors.lastname: Sugawara
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ohira
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Harada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Noda
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000601:surgery; D004938:Esophageal Neoplasms / Q000175:diagnosis / Q000601:surgery; D004945:Esophagoscopy / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007413:Intestinal Mucosa / Q000601:surgery*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008478:Mediastinal Emphysema / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed