Magnetic resonance imaging
(자기 공명 영상에서 넘어옴)
자기 공명 영상(Magnetic resonance imaging, MRI)
목차
T1 vs T2
- T1: how quickly the tissue can become magnetized.(measures the ability of protons within a tissue to exchange energy with the surrounding environment)
- Fat appears relatively bright and water relatively dark on T1-weighted images,
- T1-weighted images are good for viewing anatomy
- T2: how quickly it loses its magnetization.
- T2-weighted images are good for detecting pathology
- Fast spin echo(FSE) 연골영상에 적합
Proton density sequence
- for joint space ( hyaline cartilage and fibrocartilage)
Diffusion weighted
Gradient echo 2-D multi echo data imaging combination
- MERGE/MEDIC(me2d)/M-FFE
- For musculoskeletal imaging.
Turbo inversion recovery magnitude(TIRM)
- for osteomyelitis in bone and head and neck tumors
Susceptibility weighted image(SWI)
- phase and magnitude image.
- Both (paramagnetic) blood products and (diamagnetic) calcifications are dark on Modern SWI.
- Both are opposite SI on filtered phase images. [1]
Pelvis Dynamic MRI[2]
- The early enhancement phases (0 and 1 minute) allow identification of the subendometrial zone, which enhances earlier than the bulk of the myometrium and corresponds to the inner junctional zone. Identification of this zone is especially important in detecting early myometrial invasion because the junctional zone often becomes indistinct in post-menopausal women.
- The equilibrium phase (2–3 minutes after injection) allows better evaluation of deep myometrial invasion,
- The delayed phase (4–5 minutes) enables better evaluation of cervical stroma invasion
Pancreas dynamic MRI
- Empirical timing has been used with the arterial, venous, and delayed phases acquired 25, 60, and 180 seconds [3]
- Fat suppressed T1WI: best for pancreas cancer.