MR Enterography is commonly requested in many MR suites across the world, and the benefits of this exam are substantial to patients. Patients affected by inflammatory bowel diseases such as Crohn's Disease or ulcerative colitis will often undergo many CT scans in their lifetime. Since these diseases primarily affect people between the ages of 15 to 35, the repeated exposure to ionizing radiation comes at significant risk.
It is considered as one of
the more operator-dependending applications because the quality of the study has historically been heavily reliant on the skills and knowledge of the technologist. Although a large
contributor to image quality is protocol optimization, the pulse sequences of
today make the image quality more consistent than ever, while still offering
the flexibility to optimize as desired.
One
size does not fit all in body MR imaging. Breath-hold capacity and body habitus
can impact a tech's ability to generate consistent image quality; therefore,
shorter breath-holds and exam times can help address these issues. Common
artifacts and pitfalls often occur in fat saturation,
motion and respiratory/peristaltic, poor breath-hold, parallel imaging, contrast timing, and
DWI quality. Technologists can further optimize MR body exams by eliminating redundant scans, using workflow features such as linking, and properly ordering scans (i.e., breath-hold versus Respiratory Trigger mix before/after contrast).
MR
Enterography can provide high resolution dynamic images of bowel motility—without exposing the patient to radiation. The exam is often
used
to
identify and locate inflammation, bleeding sources, lesions, abscesses,
fistulas, and obstructions. Additionally, nce these diseases can involve any
area of the digestive tract, having the capability to image with
a large field of view is critical. MR is chosen as the modality of choice for imaging patients with these digestive
disorders.
Patient prep
The
patient fasts for six hours, but can drink sweet liquid to prevent dehydration and hypoglycemia. The patient drinks one liter of water containing 5% mannitol 30 to 40 minutes prior to the exam. The
patient receives an IV antispasmodic to stop bowel motion. The technologist
positions the patient prone on the table to spread and better visualize the bowel loops.
The
following sequences are run in the case
of a multiparametric MR imaging (based on
anatomical and quantitative imaging) of the bowel: 30
sequences are acquired, coronal and axial T2 SSFSE, 12x 3D T1 Dixon in axial
and coronal plane, coronal FIESTA cine, FIESTA coronal and axial acquisition,
3DFSE MRCP, 2 station DWI in axial plane and a coronal tetrahedral acquisition,
highly accelerated T2 and T1 FS 3DFSE volumetric imaging and non Cartesian T2
FS in axial and coronal plane. Total imaging time less than 40 minutes.
Pediatric bowel
MR multiparametric imaging (based on anatomical and quantitative imaging). In
this case example of fast imaging techniques in a case of a non cooperative 10
year old girl with Crohn s disease. MRCP, coronal and axial non cartesian T2
fat suppressed imaging and isotropic T1 Dixon post contrast acquisition offer
total evaluation of the GI tract. GE MR 750 3.0 Tesla, 32 channel body coil.
Total imaging time less than 30 minutes.
Bowel MR
multiparametric imaging (based on anatomical and quantitative imaging). In this
case example of fast imaging techniques in a case of a 45 year old male with
Crohn s disease. Breath-hold SSFSE, 3DT1 Dixon and FIESTA coronal acquisition,
reformatted DWI in all planes. GE MR 750 3.0 Tesla, 32 channel body coil. Total
imaging time less than 25 minutes.
Single breath
hold (18 seconds) highly accelerated volumetric imaging of the bowels in Crohn’s
imaging at 3 Tesla (isotropic acquisition in axial plane) based on LAVA Flex
(3D Gradient Echo T1-weighted fat-suppressed and dual-echo Dixon, R factor 5x,
32 channel body coil). 600 slices obtained in a breathhold offering high
diagnostic confidence, voxel size 0.4 mm^3. Also surface rendering depicts the
areas of the pathology and the changes in the intestine wall very accurately.
Also DWI offers the flexibility to characterize the pathologic areas. Results
of this exam have been confirmed by endoscopy and biopsy.
Highly accelerated volumetric imaging (T1 Dixon 3D), DWI and non cartesian highly accelerated T2 Fat Sat (Propeller) of the bowels in Crohn s imaging at 3 Tesla.
Fast
Bowel multiparametric MR imaging (based on anatomical and quantitative
imaging). In this case example of fast 3D and non cartesian imaging
techniques for motion suppression and tissue-water-air interfaces
imaging without artifacts. Imaging in a case of a non sedated 6 year old
male with Crohn s disease. The patient was ok with the scanning
conditions but constantly moving and interacting with the parents that were present in the scanning room in order to feel comfortable.
Pediatric
bowel MR multiparametric imaging (based on anatomical and quantitative
imaging). In this case example of coronal large FOV imaging techniques in a
case of a non cooperative 10 year old girl with Crohn s disease. Coronal non
cartesian T2 fat suppressed imaging coronal acquired high resolution
tetrahedral DWI (b1000 image). GE MR 750 3.0 Tesla, 32 channel body coil. Total
imaging time less than 4 minutes.
