MRI consists of T1 weighted image and T2 weighted image. Both depends on the timing of radiofrequency pulse sequence. In T2 images water appears bright. In T1 images fat is bright and so are methemoglobin and mucinous fluid.
In general T1 images is for finding the anatomy and T2 are for finding the pathology.
Bone and Air have low intensity on both T1 and T2
Q2) Best investigation to diagnose Colonic diverticulitis A. Ba enema B. CT scan
C. USG
D. MRI
Ans 2) b
Barium Enema are limited and give information only about the luminal pathology. They cannot be used in cases of suspected perforation,
CT abdomen is now the standard of management in acute colonic diverticulitis. It tells about the site, severity, extent and external structures involved. CT guided aspirations can also help in deciding further management options. The use of MRI and Ultrasound is not as reliable as CT
Ref Sabiston 1331-1332
Q3 ) Not a HPB contrast for MRI? a. Gadoxetate b. Mangofodipir c. Gadobenate d. Gadopentetate
Ans c , Gadobenate
Gadoxetate disodium is an MRI contrast agent with perfusion and hepatoselective properties. It works as an extracellular contrast agent for the first few minutes and then as a hepatobiliary agent for several minutes
Gadopentetate dimeglumine (.1mmol/kg) is also a contrast agent for MRI
Gadobenate dimeglumine (also known as MultiHanceTM) is an extracellular intravenous contrast agent used in magnetic resonance imaging.
Because it has 4-5% hepatobiliary uptake, it can be used as a hepatobiliary phase agent in some circumstances but requires a 1-hour delay for imaging acquisition. Because of the higher relaxivity than most other extracellular contrast agents, it is preferred in vascular imaging
Mangafodipir is a contrast agent used as a diagnostic tool administered intravenously to enhance contrast in magnetic resonance imaging (MRI) of the liver and pancreas.
