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Diffusion tensor imaging of the anal canal at 3 tesla: Feasibility and reproducibility of anisotropy measures
Author(s) -
Goh Vicky,
Tam Emily,
Taylor N. Jane,
Stirling J. James,
Simcock Ian C.,
Jones Robert Glynne,
Padhani Anwar R.
Publication year - 2012
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22873
Subject(s) - reproducibility , fractional anisotropy , diffusion mri , effective diffusion coefficient , medicine , nuclear medicine , anal canal , magnetic resonance imaging , prostate cancer , radiology , cancer , chemistry , rectum , chromatography
Purpose: To assess the feasibility and reproducibility of 3‐tesla diffusion tensor imaging (DTI) of the anal canal. Materials and Methods: DTI was performed in 25 men with no clinical history of anal canal disease undergoing MRI for prostate cancer. Analysis of fractional anisotropy (FA), relative anisotropy (RA), and apparent diffusion coefficient (ADC) were determined for the epithelial/subepithelial layer, internal sphincter, external sphincter, and puborectalis. The directionality of diffusion was recorded from color‐coded tractography maps. Obturator internus and gluteus maximus served as reference muscles. Mean (SD) of values for FA, RA, and ADC were compared using analysis of variance. Intra and inter‐rater agreement and test reproducibility (n = 5) was assessed by Bland‐Altman statistics. Results: Mean (SD) for the epithelial/subepithelial layer, internal, external sphincter, and puborectalis were as follows: FA: 0.283 (0.099); 0.337 (0.049); 0.415 (0.072); and 0.407 (0.062), respectively. RA: 0.241 (0.094); 0.292 (0.050); 0.371 (0.083); 0.361 (0.067), respectively; and ADC: 1.49 (0.23); 1.59 (0.19); 1.51 (0.28); and 1.54 (0.29) × 10 −3 mm 2 /s, respectively. Good overall intra and inter‐rater agreement and test–retest reproducibility was noted (coefficient of variation of 4.8–19.4% and 5.9–12.9%, respectively). Conclusion: Anisotropy is evident in the anal canal with good inter‐rater agreement and test reproducibility. J. Magn. Reson. Imaging 2012;35:820–826. © 2011 Wiley Periodicals, Inc.