Introducing MRI: Review of Spatial Localization and Bandwidth (29 of 56)

www.einstein.yu.edu - The twenty-ninth chapter of Dr. Michael Lipton's MRI course covers Review of Spatial Localization and Bandwidth. Dr. Lipton is associate professor radiology at Albert Einstein College of Medicine and associate director of its Gruss Magnetic Resonance Research Center.

[@bcc5084]

Thanks. .. this helps with understanding mri signal as a repair tech

[@carcaperu4041]

Question:Since there is a "conjugate symmetry" if one makes two images1)the usual way2)flop the conjugates parts of k-space together and divide by 2 and then fourrier transform it.Which is better?

[@drvishalsreenivasan3870]

God bless you sir, I’m a radiology resident from India

[@carcaperu4041]

Question:The teacher has talked about chemical shift artifact (CSA) on the slice, I imagine that there is also a CSA slice to slice.

[@makelovewithgaba]

I will love you forever.

[@HBNplague]

"Physician wants to rule out aortic dissection and spinal pathology with one study." In my opinion this is a questionable choice of testing, though of course the bedside physician's discretion may outweigh my opinion. If the doctor is worried about acute aortic dissection, then the doctor should order stat CTA of the aorta (the quick and readily available gold standard test for this problem) to rule that out first. This CT scan takes five minutes to do, unless of course the patient has a documented history of anaphylaxis to contrast or some other absolute contraindication. Aortic dissection is an imminently life-threatening diagnosis, and "convenience" of testing should never be the priority when it comes to life-threatening emergencies. If the CTA is negative, then pursue the MRI for the spine once you know the patient isn't facing the imminent possibility of death. If the patient has a dissection, it is potentially quite dangerous to put them in an MRI scanner; believe me, the bore of the magnet is a very bad place for the aorta to rupture.
Also, imaging the aorta usually requires 3D fourier transform techniques because we need to do multiplanar reconstructions, ideally at submillimeter slice thickness, to avoid missing focal dissections or other pathologies. Overall, in my eyes it's not a good idea to order an MRI of the spine and ask the reader "oh, while you're in there, check on the aorta too, there might be a dissection."