title: Subcutaneous fluid collection: An imaging marker for treatment response of infectious thoracolumbar spondylodiscitis.
abstract: OBJECTIVE
  To evaluate prevalence of subcutaneous fluid collection (SFC) in infectious thoracolumbar spondylodiscitis (SD) compared with control patients and to investigate correlation between volume changes of SFC and treatment response of SD.
  
  
  METHODS
  This retrospective study was approved by our institutional review board. From April 2011 to March 2012, 49 patients (24 SD and 25 non-SD patients) were enrolled. Prevalence of SFC was evaluated respectively for SD and non-SD patients using magnetic resonance imaging (MRI) on the sagittal short tau inversion recovery (STIR) imaging or fat-saturated T2-weighted imaging (T2WI), and compared. In SD patients with SFC, correlation was investigated between SFC volume on the 1st MRI and initial clinical status. The same analysis was conducted also for SFC volume changes from the 1st to 2nd or last MRI.
  
  
  RESULTS
  SFC was found in 20 patients with SD (83.3%) and 3 non-SD patients (12%) with significant difference (p<.001). In 20 SD patients with SFC, 17 patients had follow-up MRI. For the 1st MRI, no significant correlation was found between volume of SFC and initial status of patients, including body weight, body mass index (BMI), white blood cell (WBC), and erythrocyte sedimentation rate (ESR). However, significant positive correlations were found between changes of C-reactive protein (CRP) and SFC volume from the 1st to 2nd as well as from the 1st to the last MRI (each p<.05).
  
  
  CONCLUSIONS
  SD patients had significantly higher prevalence of SFC than non-SD patients. Volume changes of SFC had significant correlation with changes of CRP, which can be used as an imaging marker for treatment response of SD on MRI.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: tkakigi@kuhp.kyoto-u.ac.jp.
authors.forename: Takahide
authors.initials: T
authors.lastname: Kakigi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: tomokada@kuhp.kyoto-u.ac.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Radiology, Boston Medical Center, Boston University School of Medicine, FGH Building, 3rd Floor, 820 Harrison Avenue, Boston, MA 02118, USA. Electronic address: osamu.sakai@bmc.org.
authors.forename: Osamu
authors.initials: O
authors.lastname: Sakai
authors.affiliation: Department of General Internal Medicine, Rakuwakai Otowa Hospital, 2 Otowachoinji-cho, Yamashina-ku, Kyoto 607-8062, Japan. Electronic address: iwacame@hotmail.co.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Iwamoto
authors.affiliation: Department of Radiology, Rakuwakai Otowa Hospital, 2 Otowachoinji-cho, Yamashina-ku, Kyoto 607-8062, Japan. Electronic address: kubo-s@mbox.kyoto-inet.or.jp.
authors.forename: Soichi
authors.initials: S
authors.lastname: Kubo
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: yakira@kuhp.kyoto-u.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: nmdioffice@kuhp.kyoto-ac.jp.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D001826:Body Fluids; D002097:C-Reactive Protein; D015299:Discitis / Q000097:blood / Q000188:drug therapy* / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002097:C-Reactive Protein
keywords: C-reactive protein; Magnetic resonance imaging; Short tau inversion recovery; Spondylodiscitis; Subcutaneous fluid collection; Vertebral osteomyelitis