title: Comparison of diffusion-weighted imaging and contrast-enhanced T1-weighted imaging on a single baseline MRI for demonstrating dissemination in time in multiple sclerosis.
abstract: BACKGROUND
  The 2010 Revisions to the McDonald Criteria have established that dissemination in time (DIT) of multiple sclerosis (MS) can be demonstrated by simultaneous presence of asymptomatic gadolinium-enhancing and nonenhancing lesions on a single magnetic resonance imaging (MRI). However, gadolinium-based contrast agents (GBCAs) have contraindications. Diffusion-weighted imaging (DWI) can detect diffusion alterations in active inflammatory lesions. The purpose of this study was to investigate if DWI can be an alternative to contrast-enhanced T1-weighted imaging (CE T1WI) for demonstrating DIT in MS.
  
  
  METHODS
  We selected patients with clinically definite MS and evaluated their baseline brain MRI. Asymptomatic lesions were identified as either hyperintense or nonhyperintense on DWI and enhancing or nonenhancing on CE T1WI. Fisher's exact test was performed to determine whether the hyperintensity on DWI was related to the enhancement on CE T1WI (P < 0.05). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the DWI to predict lesion enhancement were calculated.
  
  
  RESULTS
  Twenty-two patients with 384 demyelinating lesions that were hyperintense on T2-weighted imaging and more than 3 mm in size were recruited. The diffusion hyperintensity and lesion enhancement were significantly correlated (P <0.001). The sensitivity, specificity, PPV, NPV and accuracy were 100%, 67.9%, 32.3%, 100% and 72.1%, respectively.
  
  
  CONCLUSIONS
  A hyperintense DWI finding does not necessarily overlap with contrast enhancement. There are many false positives, possibly representing other stages of lesion development. Although DWI may not replace CE T1WI imaging to demonstrate DIT due to the low PPV, it may serve as a screening MRI sequence where the use of GBCAs is a concern.
authors.affiliation: Department of Radiology, Taichung Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, No 66, Sec 1, Fongsing Road, Taichung Tanzih District, 427, Taiwan. rain2343@ms22.hinet.net.
authors.forename: Chung-Ping
authors.initials: CP
authors.lastname: Lo
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Kao
authors.forename: Shao-Yuan
authors.initials: SY
authors.lastname: Chen
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Chu
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Hsu
authors.forename: Ying-Chu
authors.initials: YC
authors.lastname: Chen
authors.forename: Wei-Chen
authors.initials: WC
authors.lastname: Lin
authors.forename: Dai-Wei
authors.initials: DW
authors.lastname: Liu
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Hsu
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology; D003287:Contrast Media / Q000009:adverse effects; D003711:Demyelinating Diseases / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D005682:Gadolinium / Q000009:adverse effects; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium