title: Concomitant findings and clinical significance of a fluid crescent between the iliacus muscle and iliac bone on MRI.
abstract: BACKGROUND
  Some routine magnetic resonance imaging (MRI) examinations show a thin line of fluid signal intensity along the iliac crest ("fluid crescent") between the iliacus muscle and the iliac bone. This fluid crescent has not been described before.
  
  
  OBJECTIVE
  To evaluate the clinical context and significance of the fluid crescent.
  
  
  METHODS
  MRI examinations of the abdomen and pelvis performed over 1 year were retrospectively reviewed twice for the presence of a fluid crescent. The relationship between the presence of a fluid crescent and associated abnormal findings, including ascites, iliopsoas compartment, and bone and soft tissue pathologies, was evaluated.
  
  
  RESULTS
  Forty-one out of 254 MRI studies (male:female ratio, 136:118; mean age, 42 years) demonstrated a fluid crescent (16%). Thirty-eight of them had associated MRI pathologies: edema of the hip muscles = 24, ascites = 11, iliac bone = 21, and iliopsoas compartment = 7. Correlations between the presence of a fluid crescent and pathological findings were highly significant (P < 0.0001), except for the presence of fluid in the hip joint.
  
  
  CONCLUSIONS
  A fluid crescent is an abnormal MRI finding strongly associated with iliopsoas compartment pathology, ascites, hip muscle edema, and pelvic bone abnormalities. The nature of this fluid crescent is yet to be determined.
authors.affiliation: Department of Diagnostic Imaging iriseshed@gmail.com.
authors.forename: Iris
authors.initials: I
authors.lastname: Eshed
authors.affiliation: Department of Orthopedic Surgery, Sheba Medical Center, Tel Hashomer, Israel, affiliated to the Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Boaz
authors.initials: B
authors.lastname: Liberman
authors.affiliation: Department of Diagnostic Imaging.
authors.forename: Yael
authors.initials: Y
authors.lastname: Inbar
authors.affiliation: Department of Diagnostic Imaging.
authors.forename: Michal
authors.initials: M
authors.lastname: Amitai
authors.affiliation: Department of Diagnostic Imaging.
authors.forename: Orith
authors.initials: O
authors.lastname: Portnoy
authors.affiliation: Department of Diagnostic Imaging.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Hertz
authors.affiliation: Department of Diagnostic Imaging.
authors.forename: Sara
authors.initials: S
authors.lastname: Apter
mesh_terms: D000328:Adult; D000368:Aged; D001201:Ascites / Q000175:diagnosis*; D001826:Body Fluids; D003287:Contrast Media; D004487:Edema / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007085:Ilium; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D016658:Psoas Muscles; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine
keywords: MRI; anatomy; hip; pathology; pelvis