title: Objective definition and measurement method of ground-glass opacity for planning limited resection in patients with clinical stage IA adenocarcinoma of the lung.
abstract: OBJECTIVE
  The standard operation for patients with stage IA lung adenocarcinoma is considered to be a lobectomy. Recently, some researchers have reported that patients with tumors showing greater proportions of ground-glass opacity (GGO) at computed tomography (CT) could be candidates for limited resection, because of its less aggressive nature. However, the lack of a precise definition or standard measuring method of GGO prevents its general use as an index for planning limited resection. Therefore, we attempted to define GGO based on CT number and measured it more objectively.
  
  
  METHODS
  Between 1998 and 2001, 90 patients with clinical stage IA adenocarcinoma, who underwent standard or intentional limited resection and whose images of chest high-resolution CT were preserved in Digital Imaging and Communications in Medicine (DICOM) format, constituted the study population. The tumor shadow seen on the solid window (WL, -160HU; WW, 2HU) was regarded as the central solid area of the tumor seen on the lung window, and GGO was defined as the whole tumor area with the exception of the central solid area. Each area was measured using Scion Image (Scion Corp., Frederick, MD). We analyzed the relationship between the proportion of GGO and both of pathologic findings and recurrence.
  
  
  RESULTS
  Among the 90 tumors, 31 (34.4%) were calculated to have a GGO area greater than or equal to 50%. Of these, 27 (87%) tumors were bronchioloalveolar carcinoma. Lymphatic and vascular invasions, or nodal involvement were found only in patients with a smaller proportion of GGO (<50%) (P < 0.05). During the follow-up period (median 36 months), recurrences occurred in eight patients who were diagnosed as having tumors showing smaller proportion of GGO (<50%).
  
  
  CONCLUSIONS
  Tumors with a greater proportion of GGO measured by our method are thought to have a less invasive nature. Our objective measuring method of GGO could be useful for future multicenter trials to elucidate the value of limited resection for clinical stage IA adenocarcinoma based on the proportion of GGO.
authors.affiliation: Division of Thoracic Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi 320-083, Japan. hmatsugu@tcc.pref.tochigi.jp
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Matsuguma
authors.forename: Rie
authors.initials: R
authors.lastname: Nakahara
authors.forename: Masaki
authors.initials: M
authors.lastname: Anraku
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kondo
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tsuura
authors.forename: Yukari
authors.initials: Y
authors.lastname: Kamiyama
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Mori
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012008:Recurrence; D014057:Tomography, X-Ray Computed