title: MR colonography with fecal tagging: comparison between 2D turbo FLASH and 3D FLASH sequences.
abstract: The objective of this study was to compare inversion recovery turbo 2D fast low-angle shot (FLASH) and 3D FLASH sequences for fecal-tagged MR colonography studies. Fifteen consecutive patients with indications for colonoscopy underwent MR colonography with fecal tagging. An inversion recovery turbo-FLASH sequence was applied and compared in terms of artifacts presence, efficiency for masking residual stool, and colonic wall conspicuity with a fat-saturated 3D FLASH sequence. Both sequences were acquired following administration of paramagnetic contrast agent. Contrast-to-noise ratio and relative contrast between colonic wall and lumen were calculated and compared for both sequences. Turbo 2D FLASH provided fewer artifacts, higher efficiency for masking the residual stool, and colonic wall conspicuity equivalent to 3D FLASH. An inversion time of 10 ms provided homogeneously low signal intensity of the colonic lumen. Contrast to noise between colonic wall and lumen was significantly higher in the 3D FLASH images, whereas differences in relative contrast were not statistically significant. An optimized inversion-recovery 2D turbo-FLASH sequence provides better fecal tagging results and should be added to the 3D FLASH sequence when designing dark-lumen MR colonography examination protocols.
authors.affiliation: Department of Radiology, University Hospital of Heraklion, Stavrakia, 71110, Heraklion, Crete, Greece. npapan@med.uoc.gr
authors.forename: Nickolas
authors.initials: N
authors.lastname: Papanikolaou
authors.forename: John
authors.initials: J
authors.lastname: Grammatikakis
authors.forename: Thomas
authors.initials: T
authors.lastname: Maris
authors.forename: Thomas
authors.initials: T
authors.lastname: Lauenstein
authors.forename: Panos
authors.initials: P
authors.lastname: Prassopoulos
authors.forename: Nicholas
authors.initials: N
authors.lastname: Gourtsoyiannis
mesh_terms: D001466:Barium Sulfate; D003108:Colonic Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010349:Patient Compliance; D011336:Probability; D011856:Radiographic Image Enhancement; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate