الفهرس | Only 14 pages are availabe for public view |
Abstract In conclusion, MR Enterography has emerged as a valuable tool in diagnosis and follow up of small bowel diseases. It offers a non-invasive, radiation-free method for visualizing small bowel and provide detailed information on morphology and function of small bowel, despite small bowel imaging challenges related to its long and tortuous anatomy, continuous peristaltic movement, complex histology. MR Enterography has many indications including Crohn’s and inflammatory bowel diseases “IBD” , un explained small bowel thickening, Un explained GIT bleeding, suspected small bowel mass, looking for small bowel stricture or fistula or abscess, asses small bowel obstruction, evaluated acute abdominal pain in pregnant , assess small bowel injury in trauma that can’t be detected by CT. While MR enterography is a safe Procedure, there are certain contraindications must be considered before the procedure, which divided into two categories; Absolute contraindications which include active magnetic, electric , mechanical ,metallic implants like cardiac pacemakers, cochlear implants, aneurysm clips and insulin pump, artificial limbs, hearing aids, implantable neurostimulators, infusion pump, Magnetic dental implants, Piercings. Eye metal fragments. Relative contraindications include Coronary and peripheral artery stents, Stapes implants, Surgical clips, Penile prosthesis, Joint replacement prosthesis, Ocular prosthesis, Stainless steel Intrauterine device, Inferior vena cava filter. MRE is done using multicoil surface receive arrays coil and the exam require both oral and intra-venous contrast with bowel preparation and antispasmolytic agent, MRE has wide variety of sequences including; Echoplanar imaging (EPI), Rapid acquisition with relaxation enhancement (RARE), Single Shot RARE (HASTE, TSE,FSE), Balanced steady-state free precession (bSSFP, FISP), Spoiled gradient echo (FLASH, SPGR, T1FFE), 3D T1W (Volumetric Interpolated Breath-hold Examination “VIBE, THRIVE”, Hydrographic Projection Imaging, Fat Suppression and Dixon technique , dynamic and cine imaging, DWI and perfusion technique. MRI enterography has been found to be particularly useful in diagnosis and follow up of Congenital disease (e.g duplications cyst), Inflammatory bowel disease (mainly Crohn’s disease), Autoimmune disease (mainly Celiac disease), Small bowel tumors (include benign and pre-cancerous like polyposis syndrome or malignant like small bowel adenocarcinoma). MR Enterography has a role in follow up of post chemo/radiotherapy changes and complications and in post operative adhesion detection and its complication. although CT is the main imaging for small bowel obstruction diagnosis, MRE is more valuable in detected of low grade or intermittent small bowel obstruction which can be missed on CT.MRE has found to be helpful in detected of small bowel vasculitis and ischemic conditions. MRE has a role like CT in correlated with laboratory test to diagnosis of infections diseases likely TB. While CT is the main imaging modality for acute GIT bleeding assessment, MRE is valuable in detection of occult or obscure GIT bleeding. MRE has a valuable role in investigating causes of abdominal pain in pregnancy. Comparing MR Enterography with other diagnostic methods revealed that although contrast enhanced ultrasound has similar safety features of MRE , MRE is more practical and more accurate. Comparing MRE with other invasive techniques likely, endoscopy capsule endoscopy, balloon assisted deep enteroscopy revealed although they have advantage of real visualizing of bowel mucosa and lumen and take tissue biopsy in case of endoscopy and enteroscopy , they lack MRE advantages of assessment of bowel sub-mucosa and musculosa layer and extra bowel complications, even so there was a matching between MRE and balloon assisted enteroscopy in detecting ileal lesions. MRE has found to be of higher specificity, accuracy and positive predictive value than CT Enterography and small bowel follow through, as Its ability to detect early changes in small bowel and monitor disease progression and its safe non-ionizing radiation techniques makes it a valuable tool in the long-term follow up of small bowel diseases. Furthermore, As such, it has become an indispensable tool in the assessment of small bowel diseases and is likely to continue to play an important role in the future. |