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MR Colonography: Development of Optimized Method with ex Vivo and in Vivo Systems¹

¹ From the Department of Abdominal Imaging, West Virginia University School of Medicine, Robert C. Byrd Health Sciences Center, PO Box 9235, Morgantown, WV 26505-9235. Received October 11, 2001; revision requested January 4, 2002; revision received February 20; accepted May 15. Address correspondence to D.R.M. (e-mail: dmartin@hsc.wvu.edu).

View larger version (22K): [in a new window]   Figure 1. Graphs depict polyp conspicuity versus volume for each combination of sequence and lumen contrast agent. Maximal conspicuity of the smallest polyps was obtained with the combination of true FISP (T-FISP) and water (x) or gadopentetate dimeglumine () (P < .05 [see Results]). = air. HASTE = Half-Fourier RARE, 3D-VIBE = volumetric interpolated breath-hold imaging.

View larger version (46K): [in a new window]   Figure 2a. Transverse short-axis MR images through ex vivo bovine bowel segments were obtained at the same level with (a) half-Fourier RARE, (b) true FISP, and (c) fat-suppressed volumetric interpolated breath-hold imaging. Bowel contrast agents are (left) air, (middle) dilute gadopentetate dimeglumine, and (right) water. Thin mucosal folds, with blurring, are identified in a with water contrast (arrow). Thin mucosal folds can be seen most clearly in b with water contrast (right arrow) or gadopentetate dimeglumine (middle arrow) and on c with gadopentetate dimeglumine (arrow). A 1-cm-diameter polyp is seen with water contrast (a-c, right arrowheads) or air contrast (a-c, left arrowheads). With water contrast, the polyp (a-c, right arrowheads) is shown with clearly defined margins in b and with slightly blurred margins in a and c. With air contrast, the polyp (a-c, left arrowheads) is relatively most conspicuous in c and progressively less conspicuous in a and b. However, mucosal fold detail was relatively poor with air enema contrast, regardless of sequence used. See Figure 1 for summary of findings.

View larger version (52K): [in a new window]   Figure 2b. Transverse short-axis MR images through ex vivo bovine bowel segments were obtained at the same level with (a) half-Fourier RARE, (b) true FISP, and (c) fat-suppressed volumetric interpolated breath-hold imaging. Bowel contrast agents are (left) air, (middle) dilute gadopentetate dimeglumine, and (right) water. Thin mucosal folds, with blurring, are identified in a with water contrast (arrow). Thin mucosal folds can be seen most clearly in b with water contrast (right arrow) or gadopentetate dimeglumine (middle arrow) and on c with gadopentetate dimeglumine (arrow). A 1-cm-diameter polyp is seen with water contrast (a-c, right arrowheads) or air contrast (a-c, left arrowheads). With water contrast, the polyp (a-c, right arrowheads) is shown with clearly defined margins in b and with slightly blurred margins in a and c. With air contrast, the polyp (a-c, left arrowheads) is relatively most conspicuous in c and progressively less conspicuous in a and b. However, mucosal fold detail was relatively poor with air enema contrast, regardless of sequence used. See Figure 1 for summary of findings.

View larger version (49K): [in a new window]   Figure 2c. Transverse short-axis MR images through ex vivo bovine bowel segments were obtained at the same level with (a) half-Fourier RARE, (b) true FISP, and (c) fat-suppressed volumetric interpolated breath-hold imaging. Bowel contrast agents are (left) air, (middle) dilute gadopentetate dimeglumine, and (right) water. Thin mucosal folds, with blurring, are identified in a with water contrast (arrow). Thin mucosal folds can be seen most clearly in b with water contrast (right arrow) or gadopentetate dimeglumine (middle arrow) and on c with gadopentetate dimeglumine (arrow). A 1-cm-diameter polyp is seen with water contrast (a-c, right arrowheads) or air contrast (a-c, left arrowheads). With water contrast, the polyp (a-c, right arrowheads) is shown with clearly defined margins in b and with slightly blurred margins in a and c. With air contrast, the polyp (a-c, left arrowheads) is relatively most conspicuous in c and progressively less conspicuous in a and b. However, mucosal fold detail was relatively poor with air enema contrast, regardless of sequence used. See Figure 1 for summary of findings.

View larger version (140K): [in a new window]   Figure 3a. MR images in a test subject given water contrast enema show effects of bowel wall motion and intraluminal water flow on the following images: (a) transverse true FISP, (b) transverse half-Fourier RARE, (c) sagittal true FISP, (d) sagittal half-Fourier RARE, and (e) transverse volumetric interpolated breath-hold images. Transverse images of the hepatic flexure and proximal transverse colon (a and b, respectively) and sagittal images of the descending colon and splenic flexure c and d, respectively) show large areas of signal void centrally in the lumen ( in b and d) that are not seen in a and c. The pattern is consistent with flow void artifact in b and d that results from swirling fluid. This fluid motion could be a result of convection or of bowel wall contractions. SI in a and c is relatively resistant to this effect. (e) Transverse volumetric interpolated breath-hold image obtained at the same level as were a and b shows marked deterioration of colon wall definition and development of extra lines across the bowel image (arrowheads) as a result of bowel motion. Images a and b appear relatively unaffected by bowel wall motion (arrowheads), with bowel wall appearing sharply delineated. In a, residual stool debris is shown along the dependent aspect of the proximal transverse colon (arrows), but the margins of the adjacent bowel wall (arrowheads) remain distinct.

View larger version (129K): [in a new window]   Figure 3b. MR images in a test subject given water contrast enema show effects of bowel wall motion and intraluminal water flow on the following images: (a) transverse true FISP, (b) transverse half-Fourier RARE, (c) sagittal true FISP, (d) sagittal half-Fourier RARE, and (e) transverse volumetric interpolated breath-hold images. Transverse images of the hepatic flexure and proximal transverse colon (a and b, respectively) and sagittal images of the descending colon and splenic flexure c and d, respectively) show large areas of signal void centrally in the lumen ( in b and d) that are not seen in a and c. The pattern is consistent with flow void artifact in b and d that results from swirling fluid. This fluid motion could be a result of convection or of bowel wall contractions. SI in a and c is relatively resistant to this effect. (e) Transverse volumetric interpolated breath-hold image obtained at the same level as were a and b shows marked deterioration of colon wall definition and development of extra lines across the bowel image (arrowheads) as a result of bowel motion. Images a and b appear relatively unaffected by bowel wall motion (arrowheads), with bowel wall appearing sharply delineated. In a, residual stool debris is shown along the dependent aspect of the proximal transverse colon (arrows), but the margins of the adjacent bowel wall (arrowheads) remain distinct.

View larger version (165K): [in a new window]   Figure 3c. MR images in a test subject given water contrast enema show effects of bowel wall motion and intraluminal water flow on the following images: (a) transverse true FISP, (b) transverse half-Fourier RARE, (c) sagittal true FISP, (d) sagittal half-Fourier RARE, and (e) transverse volumetric interpolated breath-hold images. Transverse images of the hepatic flexure and proximal transverse colon (a and b, respectively) and sagittal images of the descending colon and splenic flexure c and d, respectively) show large areas of signal void centrally in the lumen ( in b and d) that are not seen in a and c. The pattern is consistent with flow void artifact in b and d that results from swirling fluid. This fluid motion could be a result of convection or of bowel wall contractions. SI in a and c is relatively resistant to this effect. (e) Transverse volumetric interpolated breath-hold image obtained at the same level as were a and b shows marked deterioration of colon wall definition and development of extra lines across the bowel image (arrowheads) as a result of bowel motion. Images a and b appear relatively unaffected by bowel wall motion (arrowheads), with bowel wall appearing sharply delineated. In a, residual stool debris is shown along the dependent aspect of the proximal transverse colon (arrows), but the margins of the adjacent bowel wall (arrowheads) remain distinct.

View larger version (168K): [in a new window]   Figure 3d. MR images in a test subject given water contrast enema show effects of bowel wall motion and intraluminal water flow on the following images: (a) transverse true FISP, (b) transverse half-Fourier RARE, (c) sagittal true FISP, (d) sagittal half-Fourier RARE, and (e) transverse volumetric interpolated breath-hold images. Transverse images of the hepatic flexure and proximal transverse colon (a and b, respectively) and sagittal images of the descending colon and splenic flexure c and d, respectively) show large areas of signal void centrally in the lumen ( in b and d) that are not seen in a and c. The pattern is consistent with flow void artifact in b and d that results from swirling fluid. This fluid motion could be a result of convection or of bowel wall contractions. SI in a and c is relatively resistant to this effect. (e) Transverse volumetric interpolated breath-hold image obtained at the same level as were a and b shows marked deterioration of colon wall definition and development of extra lines across the bowel image (arrowheads) as a result of bowel motion. Images a and b appear relatively unaffected by bowel wall motion (arrowheads), with bowel wall appearing sharply delineated. In a, residual stool debris is shown along the dependent aspect of the proximal transverse colon (arrows), but the margins of the adjacent bowel wall (arrowheads) remain distinct.

View larger version (127K): [in a new window]   Figure 3e. MR images in a test subject given water contrast enema show effects of bowel wall motion and intraluminal water flow on the following images: (a) transverse true FISP, (b) transverse half-Fourier RARE, (c) sagittal true FISP, (d) sagittal half-Fourier RARE, and (e) transverse volumetric interpolated breath-hold images. Transverse images of the hepatic flexure and proximal transverse colon (a and b, respectively) and sagittal images of the descending colon and splenic flexure c and d, respectively) show large areas of signal void centrally in the lumen ( in b and d) that are not seen in a and c. The pattern is consistent with flow void artifact in b and d that results from swirling fluid. This fluid motion could be a result of convection or of bowel wall contractions. SI in a and c is relatively resistant to this effect. (e) Transverse volumetric interpolated breath-hold image obtained at the same level as were a and b shows marked deterioration of colon wall definition and development of extra lines across the bowel image (arrowheads) as a result of bowel motion. Images a and b appear relatively unaffected by bowel wall motion (arrowheads), with bowel wall appearing sharply delineated. In a, residual stool debris is shown along the dependent aspect of the proximal transverse colon (arrows), but the margins of the adjacent bowel wall (arrowheads) remain distinct.

View larger version (151K): [in a new window]   Figure 4a. Transverse MR images in a test subject given water contrast enema show the effect of residual gas on (a) true FISP and (b) volumetric interpolated breath-hold images through the splenic flexure and proximal descending colon. Fluid-gas level (arrows) is clearly visualized in a but is almost not discernible in b. Bowel wall remains visible adjacent to a gas interface (arrowheads) in b but is relatively difficult to visualize in a. Note excellent delineation of bowel wall in b, with no discernable motion artifact compared with the motion-deteriorated image in Figure 3e.

View larger version (130K): [in a new window]   Figure 4b. Transverse MR images in a test subject given water contrast enema show the effect of residual gas on (a) true FISP and (b) volumetric interpolated breath-hold images through the splenic flexure and proximal descending colon. Fluid-gas level (arrows) is clearly visualized in a but is almost not discernible in b. Bowel wall remains visible adjacent to a gas interface (arrowheads) in b but is relatively difficult to visualize in a. Note excellent delineation of bowel wall in b, with no discernable motion artifact compared with the motion-deteriorated image in Figure 3e.