MR Enterography
Cynthia Santillan, MD University of California San Diego
Examination performed after ingestion of a large volume of oral contrast meant to distend the small bowel
Combines assessment of bowel wall with
ability to visualize extraluminal disease
Overview
MR Enterography
Inflammatory bowel disease Obscure gastrointestinal bleeding
Suspected small bowel tumor Diffuse bowel disease
Intermittent SBO
Indications
Indications for Enterography
Evaluate non-accessible bowel Less invasive procedure Surveillance
IBD activity Active vs stenotic vs normal Ulcers, sinus tract, fistula, abscess Length/location of involvement
Motility
Indications
Goals of Imaging
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Technique
Instructions
Describe exam! Clear liquids after midnight NPO 2 hours prior (Colon prep) (Low Mn diet)
Goals
Decrease particulate material in bowel Decrease T1 bright material in bowel
Preparation
Patient Instructions
Oral Contrast
Low T1/T2: Iron containing compounds
High T1/T2: Dilute Gd, Fruit juices, Milk (low HU)
Options
Low T1/T2
High T1/T2
Low T1/High T2:
Water – well-tolerated, cheap, rapidly absorbed
PEG, Low dose Ba with sorbitol, methylcellulose – rapid transit, slowly absorbed, patient discomfort
Options
Oral Contrast
Delay of at least 40 min to ensure contrast has reached the terminal ileum
Most protocols require 1.5 – 2.0 liters
Current UCSD protocol: 60 min – 500mL 40 min – 500mL 20 min – 500mL Table – 400mL water
Administration
Oral Contrast
SSFSE SSFP
Oral Contrast
Inadequate distention can: Simulate bowel wall thickening
Oral Prep Goals
Oral Prep Goals
Oral Contrast
Inadequate distention can: Simulate bowel wall hyperenhancement
Spasmolytic
Glucagon (Buscopan)
IM
Split dose IV total 1mg
Medication
Performing Exam
Multiplanar - Coronals critical!
Cine Imaging – SSFP
Spasmolytic
Steady state free precession (SSFP) +/- Fat Sat
Single shot fast spin echo (SSFSE) +/- Fat Sat
Diffusion
3D T1 weighted Fat Sat Pre contrast & Dynamic Coronal
(High resolution imaging of pelvis)
Performing Exam
MR Sequences Multiplanar - Coronals critical!
SSFP – Coronal, check distension
Cine Imaging - SSFP
Spasmolytic
SSFSE – Coronal, Axial (+/-Fat Sat)
Diffusion - Axial
3D T1 weighted Fat Sat Pre contrast & Dynamic Coronal
T1 Weighted Fat Sat - Axial
Performing Exam
MR Sequences – UCSD IBD
Multiplanar - Coronals critical!
SSFP – Coronal, check distension
Spasmolytic
SSFSE – Coronal, Axial
SSFP – Axial
3D T1 weighted Fat Sat Pre contrast & Dynamic Coronal
T1 Weighted Fat Sat - Axial
Performing Exam
MR Sequences – UCSD nonIBD Reduce volume to be imaged in coronal plane
Bowel separation
Improved distention
Respiratory motion artifact
Prone
Positioning
Motility
Coronal SSFP
Prior to spasmolytics
Assess for: Fixed stenoses or
dilation Adhesions
Incremental value TBD
Performing Exam
Spasmolytic
Decrease intraluminal flow artifacts
Medication
Performing Exam
pre-Glucagon SSFSE
post-Glucagon SSFSE
post-Glucagon SSFP
Assessing intraluminal low signal
Sequence Selection
Performing Exam
SSFSE SSFP
Performing Exam
Assessing intraluminal low signal
Sequence Selection
SSFSE SSFP
Inflammatory bowel disease Obscure gastrointestinal bleeding
Suspected small bowel tumor Diffuse bowel disease
Intermittent SBO
Indications
Indications for Enterography
Considerations for CT vs MR
Young patients Frequent imaging Sinus tracts/fistula Perirectal/anal disease Iodinated contrast issues
Indications
Inflammatory Bowel Disease
Activity Indices
Crohn Disease Activity Index (CDAI) Clinical, current standard
Crohn Disease Endoscopic Index of Severity (CDEIS)
Indications
Inflammatory Bowel Disease
MR Indices
>15 MR indices have been published Magnetic Resonance Index of Activity (MaRIA) – Relative contrast enhancement, wall thickening, ulcer, edema Crohn’s Disease MRI Index (CDMRI) – Enhancement, wall thickening, mural T2, perimural T2 Clermont Score – DWI/ADC, wall thickening, edema, ulcer
Indications
Inflammatory Bowel Disease
Inflammatory Bowel Disease
Acute TI Inflammation Acute TI Inflammation
Inflammatory Bowel Disease
Acute TI Inflammation
Inflammatory Bowel Disease
Acute Colon Inflammation
Inflammatory Bowel Disease
b=500
b=1000
Ulcerations
Inflammatory Bowel Disease
Ulceration
Inflammatory Bowel Disease
Sinus Tracts
Inflammatory Bowel Disease
Chronic Strictures
Inflammatory Bowel Disease
Complex Sinus Tracts
Inflammatory Bowel Disease
Sinus Tract with Abscess
Inflammatory Bowel Disease
Small Bowel Tumor
Patients with small bowel tumors present with a variety of symptoms, depending on the location, size, & etiology of the lesion
Small Bowel Tumors Carcinoid Adenocarcinoma Gastrointestinal Stromal Tumor (GIST) Lipoma Lymphoma Metastatic Disease
OGIB/Tumor
Inflammatory Fibroid Polyp OGIB/Tumor