title: Quantitative assessment of visual estimation of the infrared indocyanine green imaging of lymph nodes retrieved at sentinel node navigation surgery for gastric cancer.
abstract: BACKGROUND
  Although the infrared indocyanine green (ICG) imaging is an effective method to identify sentinel lymph nodes (SLNs) of gastric cancer, its objectivity has not been verified.
  
  
  METHODS
  We studied 563 lymph nodes under infrared light observation from the ICG-positive lymphatic basins of 36 patients who underwent SLN-navigated gastrectomy for clinically node-negative gastric cancer. First, the rate of SLN detection, the number of SLNs and sensitivities were compared between ordinary light observation and infrared light observation. Second, 563 lymph nodes were grouped into ICG-positive and -negative under infrared light observation. The intensities of the region of interest for each lymph node defined as the lymph node on which digital imaging was performed using an imaging-software, and the region of reference defined as its surrounding background, were compared and quantified.
  
  
  RESULTS
  In the comparison of ordinary light observation with infrared light observation, the SLN identification rates were 28/36 (78 %) vs. 36/36 (100 %), the mean ± SD (minimum to maximum) number of SLNs was 3.4 ± 3.7 (0-16) vs. 9.2 ± 5.9 (2-25), and the sensitivities were 1/5 (20 %) vs. 5/5 (100 %). The ICG-positive group contained 358 lymph nodes with an intensity of 0.323 ± 1.56 (mean ± SD), and the ICG-negative group contained 205 lymph nodes with an intensity of 0.639 ± 1.93 (mean ± SD), demonstrating a significant difference between these two groups (P < 0.0001).
  
  
  CONCLUSIONS
  The significant difference in the intensity as measured by an imaging-software between ICG-positive and ICG-negative lymph nodes would erase the concern about the objectivity of the infrared ICG method for SLN-navigated surgery for early gastric cancer.
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan. ntakahashi@jikei.ac.jp.|Department of Surgery, The Jikei University Kashiwa Hospital, 163-1 Kashiwa-shita, Kashiwa, 2778567, Chiba, Japan. ntakahashi@jikei.ac.jp.
authors.forename: Naoto
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nimura
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Fujita
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamashita
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Mitsumori
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, 1058461, Tokyo, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yanaga
mesh_terms: D004396:Coloring Agents / Q000494:pharmacology; D006801:Humans; D007208:Indocyanine Green / Q000494:pharmacology*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging / Q000379:methods*; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000556:secondary*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green