title: Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent.
abstract: OBJECTIVE
  Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions.
  
  
  METHODS
  Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis.
  
  
  RESULTS
  Enhancing lesions had a significantly (P < .001) higher mean longitudinal relaxation rate (1.22 ± 0.36 versus 0.89 ± 0.24), a higher mean transverse relaxation rate (9.8 ± 2.6 versus 7.4 ± 1.9), and a lower mean proton density (77 ± 11.2 versus 90 ± 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained.
  
  
  CONCLUSIONS
  Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.
authors.affiliation: From the Departments of Radiology and Medical and Health Sciences (I.B., Ö.S.) Centre for Medical Image Science and Visualization (I.B., A.T., Ö.S., P.L., E.-M.L.) ida.blystad@regionostergotland.se.
authors.forename: I
authors.identifier: http://orcid.org/0000-0002-8857-5698
authors.initials: I
authors.lastname: Blystad
authors.affiliation: Departments of Neurology and Clinical and Experimental Medicine (I.H.).
authors.forename: I
authors.identifier: http://orcid.org/0000-0002-0135-6485
authors.initials: I
authors.lastname: Håkansson
authors.affiliation: Centre for Medical Image Science and Visualization (I.B., A.T., Ö.S., P.L., E.-M.L.) Departments of Radiation Physics and Medical and Health Sciences (A.T., P.L., E.-M.L.).
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-0928-7282
authors.initials: A
authors.lastname: Tisell
authors.affiliation: Departments of Clinical Immunology and Transfusion Medicine and Clinical and Experimental Medicine (J.E.), Linköping University, Linköping Sweden.
authors.forename: J
authors.identifier: http://orcid.org/0000-0001-9456-2044
authors.initials: J
authors.lastname: Ernerudh
authors.affiliation: From the Departments of Radiology and Medical and Health Sciences (I.B., Ö.S.) Centre for Medical Image Science and Visualization (I.B., A.T., Ö.S., P.L., E.-M.L.).
authors.forename: Ö
authors.identifier: http://orcid.org/0000-0002-7750-1917
authors.initials: Ö
authors.lastname: Smedby
authors.affiliation: Centre for Medical Image Science and Visualization (I.B., A.T., Ö.S., P.L., E.-M.L.) Departments of Radiation Physics and Medical and Health Sciences (A.T., P.L., E.-M.L.).
authors.forename: P
authors.identifier: http://orcid.org/0000-0001-8661-2232
authors.initials: P
authors.lastname: Lundberg
authors.affiliation: Centre for Medical Image Science and Visualization (I.B., A.T., Ö.S., P.L., E.-M.L.) Departments of Radiation Physics and Medical and Health Sciences (A.T., P.L., E.-M.L.) Department of Surgical Sciences/Radiology (E.-M.L.), Uppsala University, Uppsala, Sweden.
authors.forename: E-M
authors.identifier: http://orcid.org/0000-0001-6308-1387
authors.initials: EM
authors.lastname: Larsson
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA