title: Rapid ex vivo imaging of PAIII prostate to bone tumor with SWIFT-MRI.
abstract: OBJECTIVE
  The limiting factor for MRI of skeletal/mineralized tissue is fast transverse relaxation. A recent advancement in MRI technology, SWIFT (Sweep Imaging with Fourier Transform), is emerging as a new approach to overcome this difficulty. Among other techniques like UTE, ZTE, and WASPI, the application of SWIFT technology has the strong potential to impact preclinical and clinical imaging, particularly in the context of primary or metastatic bone cancers because it has the added advantage of imaging water in mineralized tissues of bone allowing MRI images to be obtained of tissues previously visible only with modalities such as computed tomography (CT). The goal of the current study is to examine the feasibility of SWIFT for the assessment of the prostate cancer induced changes in bone formation (osteogenesis) and destruction (osteolysis) in ex vivo specimens.
  
  
  METHODS
  A luciferase expressing prostate cancer cell line (PAIII) or saline control was inoculated directly into the tibia of 6-week-old immunocompromised male mice. Tumor growth was assessed weekly for 3 weeks before euthanasia and dissection of the tumor bearing and sham tibias. The ex vivo mouse tibia specimens were imaged with a 9.4 Tesla (T) and 7T MRI systems. SWIFT images are compared with traditional gradient-echo and spin-echo MRI images as well as CT and histological sections.
  
  
  RESULTS
  SWIFT images with nominal resolution of 78 μm are obtained with the tumor and different bone structures identified. Prostate cancer induced changes in the bone microstructure are visible in SWIFT images, which is supported by spin-echo, high resolution CT and histological analysis.
  
  
  CONCLUSIONS
  SWIFT MRI is capable of high-quality high-resolution ex vivo imaging of bone tumor and surrounding bone and soft tissues. Furthermore, SWIFT MRI shows promise for in vivo bone tumor imaging, with the added benefits of nonexposure to ionizing radiation, quietness, and speed.
authors.affiliation: Departments of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA; Department of Mathematics & Statistics, University of South Florida, Tampa, Florida, USA.
authors.forename: Ihor
authors.initials: I
authors.lastname: Luhach
authors.forename: Djaudat
authors.initials: D
authors.lastname: Idiyatullin
authors.forename: Conor C
authors.initials: CC
authors.lastname: Lynch
authors.forename: Curt
authors.initials: C
authors.lastname: Corum
authors.forename: Gary V
authors.initials: GV
authors.lastname: Martinez
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gillies
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D008156:Luciferases / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D013977:Tibia; D014057:Tomography, X-Ray Computed
chemical_list: D008156:Luciferases
keywords: CT; MRI; SWIFT; bone; cancer; imaging