title: Distinguishing imaging features between spinal hyperplastic hematopoietic bone marrow and bone metastasis.
abstract: OBJECTIVE
  Systematic investigations of the distinguishing imaging features between spinal hyperplastic hematopoietic bone marrow and bone metastasis have not been reported, to our knowledge. The purpose of this study was to determine the distinguishing imaging features of the 2 entities.
  
  
  METHODS
  We retrospectively reviewed the radiologic images of 8 consecutive male patients (age range, 52-78 years; mean, 64 years) with suspected spinal metastasis on MR imaging and FDG-PET, which was later confirmed as hyperplastic hematopoietic bone marrow. MR imaging, FDG-PET, CT, and bone scintigraphy images were qualitatively and/or quantitatively evaluated. Imaging findings in 24 patients with spinal metastasis were compared, and differences were statistically analyzed.
  
  
  RESULTS
  All 8 vertebral hyperplastic hematopoietic bone marrow lesions were hypointense on T1- and T2-weighted images; lesions contiguous with the adjacent vertebra were significantly more often seen in hyperplastic hematopoietic bone marrow than in metastasis (P = .035). T2 signal intensity of the lesion was significantly different between the 2 entities (P = .033). FDG-PET showed slightly higher uptake in all hyperplastic hematopoietic bone marrow lesions; their maximum standard uptake value was significantly lower than that of metastatic lesions (P = .037). CT attenuation of hyperplastic hematopoietic bone marrow was equal to or slightly higher than that of adjacent normal-appearing vertebra; the CT appearances of hyperplastic hematopoietic bone marrow and metastasis were significantly different (P < .01). Bone scintigraphy showed normal uptake for all vertebrae with hyperplastic hematopoietic bone marrow; the uptake was significantly different from that of metastasis (P < .01).
  
  
  CONCLUSIONS
  If a lesion was isointense to hyperintense to normal-appearing marrow on MR imaging or had a maximum standard uptake value of >3.6, the lesion was considered metastatic. A normal appearance on CT or bone scintigraphy excluded metastasis.
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shigematsu
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. t-hirai@kumamoto-u.ac.jp.
authors.forename: T
authors.initials: T
authors.lastname: Hirai
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawanaka
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shiraishi
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kitajima
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Uetani
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Azuma
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Iryo
authors.affiliation: From the Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D006965:Hyperplasia / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D013125:Spinal Neoplasms / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed