(Radiographics. 2001;21:S161-S172.)
© RSNA, 2001
Helping the Gastrointestinal Surgeon |
MR Enteroclysis Imaging of Crohn Disease1
Panos Prassopoulos, MD,
Nickolas Papanikolaou, BSc,
John Grammatikakis, MD,
Maria Rousomoustakaki, MD,
Thomas Maris, PhD and
Nicholas Gourtsoyiannis, MD
1 From the Departments of Radiology and Gastroenterology, University Hospital, Medical School of Crete, Stavrakia 71110, Heraklion, Crete, Greece. Presented as an education exhibit at the 2000 RSNA scientific assembly. Received February 6, 2001; revision requested March 2 and received April 6; accepted April 25. Address correspondence to N.G. (e-mail: gournick@med.uoc.gr).
 |
Abstract
|
|---|
Magnetic resonance (MR) enteroclysis imaging is emerging as a technique for evaluation of the small bowel in patients with Crohn disease. Administration of 1.5–2 L of isosmotic water solution through a nasojejunal catheter ensures distention of the bowel and facilitates identification of wall abnormalities. True fast imaging with steady-state precession (FISP), half-Fourier acquisition single-shot turbo spin-echo (HASTE), and postgadolinium T1-weighted three-dimensional fast low-angle shot sequences can be employed in a comprehensive and integrated MR enteroclysis examination protocol to overcome specific disadvantages of each of the sequences involved. Superficial abnormalities that are ideally delineated with conventional enteroclysis are not consistently depicted with MR enteroclysis. The characteristic transmural abnormalities of Crohn disease such as bowel wall thickening, linear ulcers, and cobblestoning are accurately shown with MR enteroclysis imaging, especially with the true FISP sequence. MR enteroclysis is comparable to conventional enteroclysis in the detection of the number and extent of involved small bowel segments and in the disclosure of luminal narrowing or prestenotic intestinal dilatation. The clinical utility of MR enteroclysis in Crohn disease has not been fully established. At present, the method may be used for follow-up studies of known disease, estimation of disease activity, and determination of the extramucosal extent and spread of the disease process.
Index Terms: Crohn disease, 74.262 • Enteroclysis, 74.12146, 74.1272 • Intestines, MR, 74.12143 • Intestines, stenosis or obstruction, 74.723
|
Introduction
|
|---|
Enteroclysis has been suggested as the technique of choice for the evaluation of Crohn disease of the small intestine. Distention of the small bowel lumen with barium suspension or other contrast agent facilitates the radiologic demonstration of morphologic changes caused by the disease and allows identification of even subtle mucosal abnormalities (1). However, conventional enteroclysis suffers from two major disadvantages: the limited information regarding extramural extension of Crohn disease and its complications and the radiation dose administered to patients, mostly at a young age (2). Recent reports suggest that magnetic resonance (MR) enteroclysis can be successfully employed for the evaluation of small bowel diseases (3,4). The method provides three-dimensional images with excellent soft-tissue contrast obtained in breath-hold acquisition times and with a lack of radiation exposure. Small bowel distention is achieved with intubation, while luminal opacification is based on the administration of an appropriate contrast medium. This article describes the MR enteroclysis imaging findings in 32 patients with suspected or known Crohn disease and their correlation with the corresponding findings of conventional enteroclysis. MR enteroclysis was performed first, and conventional enteroclysis followed 3–4 hours later.
|
MR Enteroclysis Technique and Pulse Sequences
|
|---|
Patients were placed in the prone position in the MR imager. Such a position exerts mild pressure to the anterior abdominal wall, facilitating separation of small bowel loops while decreasing the volume of peritoneal cavity to be imaged and, consequently, the number of coronal sections to be acquired. Through a nasojejunal catheter, a total of 1,500–2,000 mL of the water solution was injected with a manual pump (produced in-house and compatible with MR imaging) in the MR imaging room. Small bowel intubation ensured consistently adequate luminal distention in both the jejunum and the ileum (3,4). The contrast medium used at MR enteroclysis was administered in two phases. A flow rate of 80–150 mL/min was utilized during the first phase, which lasted until the contrast medium had reached the terminal ileum. During the second phase, reflex atony was created with an increase in the flow rate to 200 mL/min. Reflex atony and administration of antiperistaltic drugs were essential to acquire images free of motion artifacts. The use of an isosmotic water solution with polyethylene glycol and electrolytes (Klean-Prep; Norgine, Middlesex, England) as a contrast agent provided high endoluminal signal intensity on true fast imaging with steady-state precession (FISP) and half-Fourier acquisition single-shot turbo spin-echo (HASTE) images and low endoluminal signal intensity on T1-weighted three-dimensional fast low-angle shot (FLASH) images (4). Solutions of methylcellulose and water (3) and of barium sulfate and iron oxide particles (5) have also been proposed as contrast agents for MR enteroclysis.
In our department, all examinations were performed by means of a 1.5-T MR imager (Vision Plus; Siemens Medical Systems, Erlangen, Germany) with maximum gradient field strength of 25 mT/m and an abdominal phased-array coil. The following pulse sequences were used: standard scout T1-weighted FLASH, single-shot turbo spin echo (TSE), true FISP, HASTE, and T1-weighted three-dimensional FLASH with fat saturation. The most important sequence parameters are shown in the Table. A single-shot TSE sequence, applied every 7 seconds, was utilized to monitor the degree of distention and the filling process of the small bowel. With a true FISP sequence and imaging in the coronal plane, two image sets of 12 sections (a total of 24 images) were acquired during 18-second breath holds for each image set. Additional axial true FISP images were obtained at the area of involved segments. Insensitivity to motion artifacts, homogeneous endoluminal opacification, and high contrast between the small bowel lumen and the bowel wall (Figs 1b, 2a, 3b) are the major advantages of the true FISP sequence, whereas disadvantagesinclude increased sensitivity to susceptibility and black boundary artifacts (Figs 4, 5a, 6, 7) and a minimum 4-mm section thickness. Consequently, a HASTE sequence was applied in the same orientation as used for the true FISP sequence. Because imaging with the HASTE sequence is sensitive to intraluminal flow voids, an antiperistaltic drug that contained 1 mg of glucagon (GlucaGen; Novo Nordisk, Bagsværd, Denmark) was administered first (Figs 1c, 2b). Insensitivity to susceptibility or black boundary artifacts and high contrast between the lumen and the bowel wall are the main advantages of the HASTE sequence. However, owing to 
-space filtering effects, HASTE images do not provide information regarding the mesenteries. In these tissues with a short T2 relaxation constant, such as lymph nodes and fibrous tissue, the high-order spatial frequencies are missing and imaging results in a blurring effect. Subsequently, 0.1 mmol/kg gadolinium chelate was injected, and a T1-weighted three-dimensional FLASH sequence with fat-saturation prepulses was performed during breath holding in the coronal plane 60–80 seconds after the administration of contrast agent. In our experience, this imaging delay provides the best enhancement of the small bowel wall. T1-weighted three-dimensional FLASH images provided high spatial resolution due to thin sections (2.5 mm) and a 512 acquisition matrix (Fig 3d). Three-dimensional FLASH images are highly sensitive to motion artifacts and provide limited information about the mesenteries (6). The use of true FISP, HASTE, and postgadolinium three-dimensional FLASH with fat saturation sequences in a comprehensive examination protocol is essential to obtain all the information that the method can provide in a balanced fashion, where disadvantages of one sequence are overcome by the advantages of the other. All sequences are fast, and thus the proposed comprehensive protocol did not result in a time-consuming process. The average duration of the entire MR enteroclysis examination within the MR imaging unit was approximately 25 minutes. Patients experienced no substantial adverse reaction during the procedure.
View larger version (147K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1a. Conventional enteroclysis image (a) and coronal true FISP (b), HASTE (c), and gadolinium-enhanced three-dimensional FLASH with fat saturation (d) MR images were obtained in a patient with no abnormal findings. The normal bowel wall is depicted with low signal intensity on the true FISP and HASTE images, whereas gadolinium uptake produces high signal intensity on three-dimensional FLASH images. Isosmotic water solution acts as a positive intraluminal contrast agent on true FISP and HASTE images and as a negative agent on three-dimensional FLASH images. Intraluminal flow voids related to high-order motion of liquid inside the lumen appear on the HASTE image since it was acquired prior to administration of an antiperistaltic drug.
|
|
View larger version (148K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1b. Conventional enteroclysis image (a) and coronal true FISP (b), HASTE (c), and gadolinium-enhanced three-dimensional FLASH with fat saturation (d) MR images were obtained in a patient with no abnormal findings. The normal bowel wall is depicted with low signal intensity on the true FISP and HASTE images, whereas gadolinium uptake produces high signal intensity on three-dimensional FLASH images. Isosmotic water solution acts as a positive intraluminal contrast agent on true FISP and HASTE images and as a negative agent on three-dimensional FLASH images. Intraluminal flow voids related to high-order motion of liquid inside the lumen appear on the HASTE image since it was acquired prior to administration of an antiperistaltic drug.
|
|
View larger version (159K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1c. Conventional enteroclysis image (a) and coronal true FISP (b), HASTE (c), and gadolinium-enhanced three-dimensional FLASH with fat saturation (d) MR images were obtained in a patient with no abnormal findings. The normal bowel wall is depicted with low signal intensity on the true FISP and HASTE images, whereas gadolinium uptake produces high signal intensity on three-dimensional FLASH images. Isosmotic water solution acts as a positive intraluminal contrast agent on true FISP and HASTE images and as a negative agent on three-dimensional FLASH images. Intraluminal flow voids related to high-order motion of liquid inside the lumen appear on the HASTE image since it was acquired prior to administration of an antiperistaltic drug.
|
|
View larger version (149K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1d. Conventional enteroclysis image (a) and coronal true FISP (b), HASTE (c), and gadolinium-enhanced three-dimensional FLASH with fat saturation (d) MR images were obtained in a patient with no abnormal findings. The normal bowel wall is depicted with low signal intensity on the true FISP and HASTE images, whereas gadolinium uptake produces high signal intensity on three-dimensional FLASH images. Isosmotic water solution acts as a positive intraluminal contrast agent on true FISP and HASTE images and as a negative agent on three-dimensional FLASH images. Intraluminal flow voids related to high-order motion of liquid inside the lumen appear on the HASTE image since it was acquired prior to administration of an antiperistaltic drug.
|
|
View larger version (173K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2a. True FISP (a) and HASTE (b) coronal MR images show homogeneous opacification of the lumen. The HASTE image was acquired after administration of an antiperistaltic drug to avoid intraluminal flow voids. Thickening of the valvulae conniventes (plicae circulares) appears on both images (arrow).
|
|
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2b. True FISP (a) and HASTE (b) coronal MR images show homogeneous opacification of the lumen. The HASTE image was acquired after administration of an antiperistaltic drug to avoid intraluminal flow voids. Thickening of the valvulae conniventes (plicae circulares) appears on both images (arrow).
|
|
View larger version (150K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3a. Projectional single-shot TSE image (a) was obtained to monitor the administration of contrast agent through a nasojejunal catheter. Adequate bowel distention and excellent wall conspicuity was achieved, as seen in images obtained with all three sequences used: true FISP (b), HASTE (c), and contrast-enhanced three-dimensional FLASH with fat saturation (d). (e) Axial true FISP MR image shows wall thickening in the terminal ileum (arrow).
|
|
View larger version (170K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3b. Projectional single-shot TSE image (a) was obtained to monitor the administration of contrast agent through a nasojejunal catheter. Adequate bowel distention and excellent wall conspicuity was achieved, as seen in images obtained with all three sequences used: true FISP (b), HASTE (c), and contrast-enhanced three-dimensional FLASH with fat saturation (d). (e) Axial true FISP MR image shows wall thickening in the terminal ileum (arrow).
|
|
View larger version (176K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3c. Projectional single-shot TSE image (a) was obtained to monitor the administration of contrast agent through a nasojejunal catheter. Adequate bowel distention and excellent wall conspicuity was achieved, as seen in images obtained with all three sequences used: true FISP (b), HASTE (c), and contrast-enhanced three-dimensional FLASH with fat saturation (d). (e) Axial true FISP MR image shows wall thickening in the terminal ileum (arrow).
|
|
View larger version (165K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3d. Projectional single-shot TSE image (a) was obtained to monitor the administration of contrast agent through a nasojejunal catheter. Adequate bowel distention and excellent wall conspicuity was achieved, as seen in images obtained with all three sequences used: true FISP (b), HASTE (c), and contrast-enhanced three-dimensional FLASH with fat saturation (d). (e) Axial true FISP MR image shows wall thickening in the terminal ileum (arrow).
|
|
View larger version (86K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3e. Projectional single-shot TSE image (a) was obtained to monitor the administration of contrast agent through a nasojejunal catheter. Adequate bowel distention and excellent wall conspicuity was achieved, as seen in images obtained with all three sequences used: true FISP (b), HASTE (c), and contrast-enhanced three-dimensional FLASH with fat saturation (d). (e) Axial true FISP MR image shows wall thickening in the terminal ileum (arrow).
|
|
View larger version (164K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5a. True FISP (a) and HASTE (b) coronal MR images obtained in a patient with Crohn disease show mild wall thickening in the terminal ileum (curved arrow). The black boundary artifact is present only on the true FISP image (arrowheads), and a characteristic susceptibility artifact in a bowel segment (straight arrow) is due to trapped air in an adjacent small bowel loop.
|
|
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5b. True FISP (a) and HASTE (b) coronal MR images obtained in a patient with Crohn disease show mild wall thickening in the terminal ileum (curved arrow). The black boundary artifact is present only on the true FISP image (arrowheads), and a characteristic susceptibility artifact in a bowel segment (straight arrow) is due to trapped air in an adjacent small bowel loop.
|
|
View larger version (162K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6. Coronal true FISP MR image shows wall thickening and luminal narrowing in the terminal ileum. In the presence of wall thickening, the black boundary artifact can be easily differentiated from the moderate signal intensity of the wall. The area of low signal intensity in the cecum corresponds to an accumulation of air in the region due to the prone position of the patient.
|
|
View larger version (118K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7. Axial true FISP MR image obtained in a patient with small bowel stenosis shows asymmetric involvement (arrowheads) between the mesenteric and antimesenteric border. Black boundary artifact is present along the bowel wall.
|
|
MR imaging of the small bowel without intubation has also been proposed (7–10). Various contrast agents for luminal opacification, including iron oxide particles (7), mannitol solution (8), barium sulfate solution (9), and pure water (10), have been used. A major limitation of all protocols for MR imaging examination of the small bowel without intubation is the lack of adequate distention of the intestinal lumen, which is considered a prerequisite for a detailed and accurate evaluation of small bowel abnormalities (3,11). Subtle mucosal abnormalities may be missed in a collapsed loop, and inadequate distention may simulate wall thickening or abnormal enhancement (12).
|
MR Enteroclysis Findings in Crohn Disease
|
|---|
Superficial Abnormalities
Early lesions of Crohn disease such as blunting, flattening, thickening, distortion, and straightening of the valvulae conniventes and tiny aphthae were clearly shown at conventional enteroclysis, but they were not consistently depicted with MR enteroclysis due to its inadequate spatial resolution. The valvulae conniventes were shown to their best advantage and distortion of the mucosal folds was easily detected with MR enteroclysis (Fig 2a, 2b). Dedicated ultrafast, high-resolution sequences and stronger gradients may allow detection of the above early but not specific manifestations of the disease in the near future.
Transmural Abnormalities
The characteristic discrete longitudinal or transverse ulcers of Crohn disease could be shown at MR enteroclysis, provided there was satisfactory distention and opacification of the bowel (Fig 8b, 8e). MR enteroclysis was less sensitive than conventional enteroclysis in the detection of linear ulcers due to low spatial resolution and lack of compression techniques. Thin high-signal-intensity lines within the bowel wall on true FISP MR images represented linear ulcers. Cobblestoning was caused mostly by a combination of longitudinal and transverse ulceration and was easily shown with MR enteroclysis (Fig 8b). The true FISP sequence was superior to HASTE in showing linear ulcers, cobblestoning, and intramural tracts, while the three-dimensional FLASH sequence was less satisfactory in depicting such lesions smaller than 3 mm in diameter. Bowel wall thickening was clearly shown with all MR enteroclysis sequences (Figs 8–11). The thickened wall had moderate signal intensity on true FISP images and could be easily differentiated from black boundary artifact (Fig 6). Bowel wall thickness and length of small bowel involvement could be measured on MR enteroclysis images. Narrowing of the lumen and associated prestenotic dilatation were easily recognized on MR enteroclysis images obtained with all sequences (Figs 8c, 8d, 9b, 9c). Asymmetric involvement, pseudodiverticula formation, and skip or multiple lesions were easily depicted at MR enteroclysis (Fig 7).
View larger version (125K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8a. Conventional enteroclysis image (a) and coronal true FISP (b, c) and postgadolinium three-dimensional FLASH (d, e) MR images were obtained in a patient with severe Crohn disease. Intersecting longitudinal and transverse ulcers with intervening protruding edematous mucosa shown on the conventional enteroclysis image (a) are also seen on a true FISP sectional image (arrow, b). A deep linear ulcer is disclosed on true FISP and three-dimensional FLASH images (white arrowhead, c, e). Segmental wall thickening is shown on conventional enteroclysis (a) and all MR enteroclysis (b-e) images. Marked postgadolinium contrast enhancement corresponding to disease activity is observed across the whole thickened wall (wide solid arrow, d, e). Luminal narrowing and prestenotic dilatation are also shown in an adjacent small bowel segment (open arrow, c, d). The comb sign is depicted at the mesenteric border of an involved loop with active disease (solid arrows, c). In addition, a small mesenteric lymph node seen as an area of low signal intensity on a true FISP MR image (black arrowhead, c) exhibits enhancement on a T1-weighted postgadolinium three-dimensional FLASH MR image (thin arrow, e).
|
|
View larger version (147K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8b. Conventional enteroclysis image (a) and coronal true FISP (b, c) and postgadolinium three-dimensional FLASH (d, e) MR images were obtained in a patient with severe Crohn disease. Intersecting longitudinal and transverse ulcers with intervening protruding edematous mucosa shown on the conventional enteroclysis image (a) are also seen on a true FISP sectional image (arrow, b). A deep linear ulcer is disclosed on true FISP and three-dimensional FLASH images (white arrowhead, c, e). Segmental wall thickening is shown on conventional enteroclysis (a) and all MR enteroclysis (b-e) images. Marked postgadolinium contrast enhancement corresponding to disease activity is observed across the whole thickened wall (wide solid arrow, d, e). Luminal narrowing and prestenotic dilatation are also shown in an adjacent small bowel segment (open arrow, c, d). The comb sign is depicted at the mesenteric border of an involved loop with active disease (solid arrows, c). In addition, a small mesenteric lymph node seen as an area of low signal intensity on a true FISP MR image (black arrowhead, c) exhibits enhancement on a T1-weighted postgadolinium three-dimensional FLASH MR image (thin arrow, e).
|
|
View larger version (160K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8c. Conventional enteroclysis image (a) and coronal true FISP (b, c) and postgadolinium three-dimensional FLASH (d, e) MR images were obtained in a patient with severe Crohn disease. Intersecting longitudinal and transverse ulcers with intervening protruding edematous mucosa shown on the conventional enteroclysis image (a) are also seen on a true FISP sectional image (arrow, b). A deep linear ulcer is disclosed on true FISP and three-dimensional FLASH images (white arrowhead, c, e). Segmental wall thickening is shown on conventional enteroclysis (a) and all MR enteroclysis (b-e) images. Marked postgadolinium contrast enhancement corresponding to disease activity is observed across the whole thickened wall (wide solid arrow, d, e). Luminal narrowing and prestenotic dilatation are also shown in an adjacent small bowel segment (open arrow, c, d). The comb sign is depicted at the mesenteric border of an involved loop with active disease (solid arrows, c). In addition, a small mesenteric lymph node seen as an area of low signal intensity on a true FISP MR image (black arrowhead, c) exhibits enhancement on a T1-weighted postgadolinium three-dimensional FLASH MR image (thin arrow, e).
|
|
View larger version (148K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8d. Conventional enteroclysis image (a) and coronal true FISP (b, c) and postgadolinium three-dimensional FLASH (d, e) MR images were obtained in a patient with severe Crohn disease. Intersecting longitudinal and transverse ulcers with intervening protruding edematous mucosa shown on the conventional enteroclysis image (a) are also seen on a true FISP sectional image (arrow, b). A deep linear ulcer is disclosed on true FISP and three-dimensional FLASH images (white arrowhead, c, e). Segmental wall thickening is shown on conventional enteroclysis (a) and all MR enteroclysis (b-e) images. Marked postgadolinium contrast enhancement corresponding to disease activity is observed across the whole thickened wall (wide solid arrow, d, e). Luminal narrowing and prestenotic dilatation are also shown in an adjacent small bowel segment (open arrow, c, d). The comb sign is depicted at the mesenteric border of an involved loop with active disease (solid arrows, c). In addition, a small mesenteric lymph node seen as an area of low signal intensity on a true FISP MR image (black arrowhead, c) exhibits enhancement on a T1-weighted postgadolinium three-dimensional FLASH MR image (thin arrow, e).
|
|
View larger version (143K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8e. Conventional enteroclysis image (a) and coronal true FISP (b, c) and postgadolinium three-dimensional FLASH (d, e) MR images were obtained in a patient with severe Crohn disease. Intersecting longitudinal and transverse ulcers with intervening protruding edematous mucosa shown on the conventional enteroclysis image (a) are also seen on a true FISP sectional image (arrow, b). A deep linear ulcer is disclosed on true FISP and three-dimensional FLASH images (white arrowhead, c, e). Segmental wall thickening is shown on conventional enteroclysis (a) and all MR enteroclysis (b-e) images. Marked postgadolinium contrast enhancement corresponding to disease activity is observed across the whole thickened wall (wide solid arrow, d, e). Luminal narrowing and prestenotic dilatation are also shown in an adjacent small bowel segment (open arrow, c, d). The comb sign is depicted at the mesenteric border of an involved loop with active disease (solid arrows, c). In addition, a small mesenteric lymph node seen as an area of low signal intensity on a true FISP MR image (black arrowhead, c) exhibits enhancement on a T1-weighted postgadolinium three-dimensional FLASH MR image (thin arrow, e).
|
|
View larger version (134K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9a. Active Crohn disease in the terminal ileum. (a) Conventional enteroclysis image shows an ulceronodular mucosal pattern. (b) Postgadolinium three-dimensional FLASH image shows enhancement of the involved bowel wall segment. Narrowing of the involved bowel segment with prestenotic dilatation is shown on conventional enteroclysis (a), postgadolinium three-dimensional FLASH (b), and true FISP (c) images.
|
|
View larger version (94K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9b. Active Crohn disease in the terminal ileum. (a) Conventional enteroclysis image shows an ulceronodular mucosal pattern. (b) Postgadolinium three-dimensional FLASH image shows enhancement of the involved bowel wall segment. Narrowing of the involved bowel segment with prestenotic dilatation is shown on conventional enteroclysis (a), postgadolinium three-dimensional FLASH (b), and true FISP (c) images.
|
|
View larger version (94K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9c. Active Crohn disease in the terminal ileum. (a) Conventional enteroclysis image shows an ulceronodular mucosal pattern. (b) Postgadolinium three-dimensional FLASH image shows enhancement of the involved bowel wall segment. Narrowing of the involved bowel segment with prestenotic dilatation is shown on conventional enteroclysis (a), postgadolinium three-dimensional FLASH (b), and true FISP (c) images.
|
|
View larger version (99K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10a. Ileocolic anastomosis after resection of a bowel segment in a patient with Crohn disease. Conventional enteroclysis image (a) and HASTE (b), postgadolinium three-dimensional FLASH (c), and true FISP coronal (d) MR images show wall thickening (b-d) and luminal narrowing (a-d). Mesenteric involvement with small lymph nodes and the comb sign (arrowheads, d) are better depicted on the true FISP image. Superficial ulcers are shown on a and b (arrows).
|
|
View larger version (115K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10b. Ileocolic anastomosis after resection of a bowel segment in a patient with Crohn disease. Conventional enteroclysis image (a) and HASTE (b), postgadolinium three-dimensional FLASH (c), and true FISP coronal (d) MR images show wall thickening (b-d) and luminal narrowing (a-d). Mesenteric involvement with small lymph nodes and the comb sign (arrowheads, d) are better depicted on the true FISP image. Superficial ulcers are shown on a and b (arrows).
|
|
View larger version (97K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10c. Ileocolic anastomosis after resection of a bowel segment in a patient with Crohn disease. Conventional enteroclysis image (a) and HASTE (b), postgadolinium three-dimensional FLASH (c), and true FISP coronal (d) MR images show wall thickening (b-d) and luminal narrowing (a-d). Mesenteric involvement with small lymph nodes and the comb sign (arrowheads, d) are better depicted on the true FISP image. Superficial ulcers are shown on a and b (arrows).
|
|
View larger version (122K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10d. Ileocolic anastomosis after resection of a bowel segment in a patient with Crohn disease. Conventional enteroclysis image (a) and HASTE (b), postgadolinium three-dimensional FLASH (c), and true FISP coronal (d) MR images show wall thickening (b-d) and luminal narrowing (a-d). Mesenteric involvement with small lymph nodes and the comb sign (arrowheads, d) are better depicted on the true FISP image. Superficial ulcers are shown on a and b (arrows).
|
|
View larger version (109K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11a. Wall thickening is seen in all true FISP images (b-d). Intramural tracts are shown on the conventional enteroclysis image (arrows, a) and true FISP images (arrow, b, d).
|
|
View larger version (114K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11b. Wall thickening is seen in all true FISP images (b-d). Intramural tracts are shown on the conventional enteroclysis image (arrows, a) and true FISP images (arrow, b, d).
|
|
View larger version (119K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11c. Wall thickening is seen in all true FISP images (b-d). Intramural tracts are shown on the conventional enteroclysis image (arrows, a) and true FISP images (arrow, b, d).
|
|
View larger version (105K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11d. Wall thickening is seen in all true FISP images (b-d). Intramural tracts are shown on the conventional enteroclysis image (arrows, a) and true FISP images (arrow, b, d).
|
|
MR enteroclysis was comparable to conventional enteroclysis in the detection, localization, and estimation of the length of all involved small bowel segments in our series. Conventional enteroclysis findings concerning thickening of the bowel wall, luminal narrowing, or high-grade stenosis with prestenotic dilatation were verified at MR enteroclysis in all our cases.
Extramural Manifestations and Complications
MR enteroclysis had a clear advantage over conventional enteroclysis in the demonstration of extramural manifestations or complications of Crohn disease. The extent of fibrofatty proliferation and its composition—mostly fatty or mostly fibrotic—could be assessed with MR enteroclysis, especially when true FISP images were obtained. Fibrofatty proliferation was suspected at conventional enteroclysis by separating adjacent small bowel loops in fewer than half of the cases depicted at MR enteroclysis in our series. Small mesenteric lymph nodes (Figs 8c, 8e, 10d) were easily detected by their low signal intensity within the high-signal-intensity mesenteric fat on true FISP images. Their presence was not as obvious with other MR enteroclysis sequences due to short T2 filtering effects on HASTE images and to saturation of mesenteric fat signal on three-dimensional FLASH images. Sinus tracts and fistulas were disclosed by the high signal intensity of their fluid content on true FISP (Fig 11b–d) and HASTE images, but they could be missed on the three-dimensional FLASH images due to limited contrast with surrounding tissues. All fistulas shown at conventional enteroclysis were also depicted at MR enteroclysis, while only half of the sinus tracts were detected at MR enteroclysis, even in retrospect in our series. Abscesses could be recognized by their fluid content and contrast enhancement of the wall. There were strong indications that disease activity can be appreciated with MR enteroclysis (7,8). The so-called comb sign, corresponding to increased mesenteric vascularity, could be ideally seen on true FISP images (Figs 8c, 10d) close to the mesenteric border of a small bowel segment in the form of short, parallel, low-signal-intensity linear structures perpendicular to the intestinal long axis. The comb sign could be seen on three-dimensional FLASH images as high-signal-intensity linear elements (Fig 8e). Contrast enhancement was considered the most important indication of disease activity (7,8), and it could be appreciated on T1-weighted three-dimensional FLASH images (Figs 8d, 8e, 9b). Active disease in small bowel segments might also be manifested by high signal intensity of the intestinal wall on T2-weighted images (7).
|
Conclusions
|
|---|
MR enteroclysis imaging is an emerging technique for the assessment of small bowel pathologic conditions, but its clinical utility has not been fully established so far. Initial experience shows that the method is complementary to conventional enteroclysis in the detection of superficial and transmural abnormalities in patients with Crohn disease. In addition, MR enteroclysis can provide excellent information concerning disease activity, mesenteric involvement, and complications of Crohn disease. At present, MR enteroclysis may not be suggested for the initial imaging evaluation of suspected Crohn disease, but it already has a valuable and promising role for follow-up imaging of the disease and detection of its complications.
|
Footnotes
|
|---|
Abbreviations: FISP = fast imaging with steady-state precession,
FLASH = fast low-angle shot,
HASTE = half-Fourier acquisition single-shot turbo spin echo,
TSE = turbo spin echo
|
References
|
|---|
-
Nolan DJ, Gourtsoyiannis NC. Crohn’s disease of the small intestine: a review of the radiological appearances in 100 consecutive patients examined by a barium infusion technique. Clin Radiol 1980; 31:597-603.[Medline]
-
Ruiz-Cruces R, Ruiz F, Perez-Martinez M, Lopez J, Tort Ausina I, de los Rios AD. Patient dose from barium procedures. Br J Radiol 2000; 73:752-761.[Abstract]
-
Umschaden HW, Szolar D, Gasser J, Umschaden M, Haselbach H. Small-bowel disease: comparison of MR enteroclysis images with conventional enteroclysis and surgical findings. Radiology 2000; 215:717-725.[Abstract/Free Full Text]
-
Gourtsoyiannis NC, Papanikolaou N, Grammatikakis J, Maris T, Prassopoulos P. MR imaging of the small bowel with a true-FISP sequence after enteroclysis with water solution. Invest Radiol 2000; 35:707-711.[Medline]
-
Holzknecht N, Helmberger T, von Ritter C, Gauger J, Faber S, Reiser M. MRI of the small intestine with rapid MRI sequences in Crohn disease after enteroclysis with oral iron particles. Radiologe 1998; 38:29-36[German].[Medline]
-
Gourtsoyiannis NC, Papanikolaou N, Grammatikakis N, Maris T, Prassopoulos P. MR enteroclysis protocol optimization: comparison between 3D FLASH with fat saturation after intravenous gadolinium injection and true FISP sequences. Eur Radiol 2001; 11:908-913.[Medline]
-
Maccioni F, Viscido A, Broglia L, et al. Evaluation of Crohn disease activity with magnetic resonance imaging. Abdom Imaging 2000; 25:219-228.[Medline]
-
Schunk K, Kern A, Oberholzer K, et al. Hydro-MRI in Crohn’s disease: appraisal of disease activity. Invest Radiol 2000; 35:431-437.[Medline]
-
Low RN, Francis IR, Politoske D, Bennett M. Crohn’s disease evaluation: comparison of contrast-enhanced MR imaging and single-phase helical CT scanning. J Magn Reson Imaging 2000; 11:127-135.[Medline]
-
Lomas DJ, Graves MJ. Small bowel MRI using water as a contrast medium. Br J Radiol 1999; 72:994-997.[Abstract]
-
Maglinte DDT, Siegelman ES, Kelvin FM. MR enteroclysis: the future of small-bowel imaging (editorial). Radiology 2000; 215:639-641.[Free Full Text]
-
Low RN, Francis IR. MR imaging of the gastrointestinal tract with i.v., gadolinium and diluted barium oral contrast media compared with unenhanced MR imaging and CT. AJR 1997; 169:1051-1059.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
I. Pedrosa, E. A. Zeikus, D. Levine, and N. M. Rofsky
MR Imaging of Acute Right Lower Quadrant Pain in Pregnant and Nonpregnant Patients
RadioGraphics,
May 1, 2007;
27(3):
721 - 743.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A C Planner, A Phillips, and H K Bungay
The role of imaging in small bowel disease
Imaging,
December 1, 2006;
18(4):
228 - 256.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. A. Kuehle, W. Ajaj, S. C. Ladd, S. Massing, J. Barkhausen, and T. C. Lauenstein
Hydro-MRI of the Small Bowel: Effect of Contrast Volume, Timing of Contrast Administration, and Data Acquisition on Bowel Distention
Am. J. Roentgenol.,
October 1, 2006;
187(4):
W375 - W385.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. Maccioni, A. Bruni, A. Viscido, M. C. Colaiacomo, A. Cocco, C. Montesani, R. Caprilli, and M. Marini
MR Imaging in Patients with Crohn Disease: Value of T2- versus T1-weighted Gadolinium-enhanced MR Sequences with Use of an Oral Superparamagnetic Contrast Agent
Radiology,
December 21, 2005;
(2005)
2381040244.
[Abstract]
[Full Text]
|
|
|
|
|
|
|
A. Furukawa, T. Saotome, M. Yamasaki, K. Maeda, N. Nitta, M. Takahashi, T. Tsujikawa, Y. Fujiyama, K. Murata, and T. Sakamoto
Cross-sectional Imaging in Crohn Disease
RadioGraphics,
May 1, 2004;
24(3):
689 - 702.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. C. Lauenstein, H. Schneemann, F. M. Vogt, C. U. Herborn, S. G. Ruhm, and J. F. Debatin
Optimization of Oral Contrast Agents for MR Imaging of the Small Bowel
Radiology,
July 1, 2003;
228(1):
279 - 283.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
