title: The utility of in-phase/opposed-phase imaging in differentiating malignancy from acute benign compression fractures of the spine.
abstract: OBJECTIVE
  Benign and malignant fractures of the spine may have similar signal intensity characteristics on conventional MR imaging sequences. This study assesses whether in-phase/opposed-phase imaging of the spine can differentiate these 2 entities.
  
  
  METHODS
  Twenty-five consecutive patients who were evaluated for suspected malignancy (lymphoma [4 patients], breast cancer [3], multiple myeloma [2], melanoma [2], prostate [2], and renal cell carcinoma [1]) or for trauma to the thoracic or lumbar spine were entered into this study. An 18-month clinical follow-up was performed. Patients underwent standard MR imaging with an additional sagittal in-phase (repetition time [TR], 90-185; echo time [TE], 2.4 or 6.5; flip angle, 90 degrees ) and opposed-phase gradient recalled-echo sequence (TR, 90-185, TE, 4.6-4.7, flip angle, 90 degrees ). Areas that were of abnormal signal intensity on the T1 and T2 sequences were identified on the in-phase/opposed-phase sequences. An elliptical region of interest measurement of the signal intensity was made on the abnormal region on the in-phase as well as on the opposed-phase images. A computation of the signal intensity ratio (SIR) in the abnormal marrow on the opposed-phase to signal intensity measured on the in-phase images was made.
  
  
  RESULTS
  Twenty-one patients had 49 vertebral lesions, consisting of 20 malignant and 29 benign fractures. There was a significant difference (P < .001, Student t test) in the mean SIR for the benign lesions (mean, 0.58; SD, 0.02) compared with the malignant lesions (mean, 0.98; SD, 0.095). If a SIR of 0.80 as a cutoff is chosen, with >0.8 defined as malignant and <0.8 defined as a benign result, in-phase/opposed-phase imaging correctly identified 19 of 20 malignant lesions and 26 of 29 benign lesions (sensitivity, 0.95; specificity, 0.89).
  
  
  CONCLUSIONS
  There is significant difference in signal intensity between benign compression fractures and malignancy on in-phase/opposed-phase MR imaging.
authors.affiliation: Department of Radiology, The University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5067, USA.
authors.forename: W K
authors.initials: WK
authors.lastname: Erly
authors.forename: E S
authors.initials: ES
authors.lastname: Oh
authors.forename: E K
authors.initials: EK
authors.lastname: Outwater
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D050815:Fractures, Compression / Q000175:diagnosis*; D005598:Fractures, Spontaneous / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012680:Sensitivity and Specificity; D016103:Spinal Fractures / Q000175:diagnosis*; D013125:Spinal Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000556:secondary; D013131:Spine / Q000473:pathology