title: The optimal analysis of MRI data to quantify the distribution of a microbicide.
abstract: OBJECTIVE
  The objective of this study was to systematically review the use of MRI for the evaluation of deployment characteristics of vaginal microbicides and to understand the relationship of gel spread with potential influencing factors.
  
  
  METHODS
  Data from four clinical trials that used MRI to assess the deployment of a vaginal gel were combined. A linear mixed model best represented the spread of gel over time. Significant covariates that influence vaginal gel spread are baseline dimensions of the vagina, time from insertion, gel type, ambulation and volume of gel.
  
  
  RESULTS
  These data demonstrate that MRI has outstanding intraperson validity and reproducibility. Therefore, paired design, using linear modeling adjusting for significant covariates, is the most efficient study design for comparison of products or volumes. Division of the vagina into two distinct anatomical regions best explains difference in gel spread, i.e., upper area (above the pelvic diaphragm) and lower area (below pelvic diaphragm).
  
  
  CONCLUSIONS
  We conclude that the concept of spread from the cervix to the introits, in one dimension, is inadequate to explain spread of gel due to the complex shape of the vagina.
authors.affiliation: Penn Fertility Care, Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, 19104, USA. kbarnhart@mail.obgyn.upenn.edu
authors.forename: Kurt T
authors.initials: KT
authors.lastname: Barnhart
authors.forename: E Scott
authors.initials: ES
authors.lastname: Pretorius
authors.forename: David M
authors.initials: DM
authors.lastname: Shera
authors.forename: Mayadah
authors.initials: M
authors.lastname: Shabbout
authors.forename: Alka
authors.initials: A
authors.lastname: Shaunik
mesh_terms: D000293:Adolescent; D000328:Adult; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000032:analysis* / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014621:Vagina / Q000033:anatomy & histology / Q000737:chemistry* / Q000378:metabolism; D014622:Vaginal Creams, Foams, and Jellies
chemical_list: D000890:Anti-Infective Agents; D014622:Vaginal Creams, Foams, and Jellies