title: Visualization of stress fractures of the foot using PET-MRI: a feasibility study.
abstract: BACKGROUND
  Diagnosis and treatment of stress fractures still remains to be a clinical and radiological challenge. Therapeutic options vary from conservative treatment to surgical treatment without a clear treatment concept. Recently the combination of PET and MRI has been introduced, aiming a superior diagnostic accuracy in clinical practice. Therefore the aim of our study was to analyse whether PET-MRI would be a feasible technique to recognize stress fractures of the foot and to analyse if our conservative treatment plan leads to a good clinical outcome.
  
  
  METHODS
  Therefore, 20 patients with suspected stress fractures of the foot and ankle underwent plain radiography and (18)F-Fluoride PET-MRI. Two blinded readers assessed in consensus both imaging techniques for the presence of stress fracture, stress reaction or osteoarthritis. Patients with stress fractures or stress reactions in the foot and ankle area underwent our conservative treatment plan, with immobilization in a VACO®ped cast for 6 weeks under partial weight bearing on forearm crutches. The benefit of our conservative therapeutic concept was evaluated by the patients on the basis of VAS and FAOS scoring systems before and after treatment.
  
  
  RESULTS
  8 out of 20 patients underwent conservative treatment after diagnosis of either a stress fracture or a stress reaction of the foot and ankle area. PET-MRI identified four stress fractures and seven stress reactions. In all cases, no pathological findings were present on plain X-ray. FAOS and VAS significantly improved according to the patients' records.
  
  
  CONCLUSIONS
  PET-MRI seems to be a useful modality to diagnose stress fractures and stress reactions of the foot and ankle area, especially when conventional modalities, such as plain radiographs fail. Conservative management is a promising therapeutic option for the treatment of stress fractures. To rule out the benefits compared to a surgical treatment plan, further studies are needed.
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. moritz.croenlein@mri.tum.de.
authors.forename: Moritz
authors.initials: M
authors.lastname: Crönlein
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. isabel.rauscher@tum.de.
authors.forename: Isabel
authors.initials: I
authors.lastname: Rauscher
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. Ambros.Beer@uniklinik-ulm.de.|Department of Nuclear Medicine, University Hospital Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany. Ambros.Beer@uniklinik-ulm.de.
authors.forename: Ambros J
authors.initials: AJ
authors.lastname: Beer
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. markus.schwaiger@tum.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.affiliation: Musculoskeletal Imaging Department of Radiology, Kantonsspital Graubünden, Loëstrasse 170, 7000, Chur, Switzerland. schaeffeler@me.com.|Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. schaeffeler@me.com.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schäffeler
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. marc.beirer@mri.tum.de.
authors.forename: Marc
authors.initials: M
authors.lastname: Beirer
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. stephan.huber@mri.tum.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Huber
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. g_sandmann@hotmail.com.|Clinic for Trauma and Reconstructive Surgery, BGU Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany. g_sandmann@hotmail.com.
authors.forename: Gunther H
authors.initials: GH
authors.lastname: Sandmann
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. peter.biberthaler@mri.tum.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Biberthaler
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. matthias.eiber@tum.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Eiber
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany. chlodwig.kirchhoff@mri.tum.de.
authors.forename: Chlodwig
authors.initials: C
authors.lastname: Kirchhoff
mesh_terms: D000328:Adult; D000368:Aged; D005240:Feasibility Studies; D005260:Female; D005462:Fluorine Radioisotopes; D018409:Foot Injuries / Q000175:diagnosis* / Q000628:therapy; D050723:Fractures, Bone / Q000175:diagnosis* / Q000628:therapy; D015775:Fractures, Stress / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D055815:Young Adult
chemical_list: D005462:Fluorine Radioisotopes