Radiology - MRI

klistu's version from 2016-03-27 19:42


Question Answer
Mostly composed of fat, which has a short relaxation time and thus shows up at high intensity for T1 or low intensity for T2Bone Marrow
Lacks free hydrogen, so it appears to have low signal intensity on all imagesCortical Bone
Have low hydrogen content and low intensity in all images, but are contrasted best in T1 weighted imagesTendons
Has a high T1 and low T2 signal intensitySubcutaneous Fat
Shows up with low intensity on MRI so contrast media is required to help visualizeVascular Structures
Intermediate hydrogen density, shows up as intermediate intensity on all imagesMuscle


Question Answer
Will typically show up as a decrease in signal intensity on T1 with diffuse increase in intensity on T2 due to localized inflammationOsseous Trauma
Will show a well-defined line of demarcation between viable bone and devascularized bone on T1Avascular Necrosis
Will show up as a decreased area of signal intensity on T1 in the acute stage, but as the condition becomes chronic the intensity increasesOsteochondritis Dessicans
Is best visualized as increased intensity on T2 or STIR images due to inflammation in the areaSoft Tissue Infection
Shows up as high intensity on T2 for cortical bone as well as low signal intensity on T1 for medullary boneOsteomyelitis
Shows up as a decrease in intensity on T1 and T2 for affected jointsCharcot Neuroarthropathy
Typically have low to intermediate signal on T1 and higher intesnity on T2, but may be high on T1 if fat or blood-filled. Calcification will also show up as lower intensity on all imagesBone Tumors
Shows up with low T1 intensity and high T2 intensity based on composition. Benign lesions tend to be well demarcated, homogenous, and have less pronounced change in signal intensitySoft Tissue Tumors
Easy to pick out on MRI because they have low T1 and very high T2 signal intensityGanglion Cyst
Shows up as homogenous and loculated with high T2 and STIR intensity due to cartilage, calcifications may show up as a heterogenous intensityEnchondroma
Tend to be superficial homogeonous lesions with the same signal intensity as surrounding fat, unless calcifications are presentLipomas

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