MR Scan Technology

---

Terminology

MRI - Magnetic resonance imaging

• RF pulse excites protons, protons emit energy as RF signal after returning to equilibrium
• Vary the sequence of RF pulse applied/collected to create different images

	Dark	Bright
	Low signal collected	High signal collected
T1-W	Water (CSF, edema), calcium	Lipid, gadolinium
T2-W	Calcium (bone)	Water (CSF, edema)

T1 (anatomical)

• spin-lattice relaxation time (time constant in the z-direction)
• fast to acquire
• excellent structural detail (e.g. white and gray matter)
• good spatial resolution

T2 (pathological)

• spin-spin relaxation time (time constant for the relaxation process in the xy-plane)
• slower to acquire --> usually lower resolution than T1
• excellent for finding lesions

W - weighted
STIR - short tau inversion recovery

FFE - fast field echo
TSE - turbo spin echo
TFE - turbo field echo

Tra - transversal
Sag - saggital
Cor - coronal
Ax - axial

CSP
HR
Edema
3D VISTA
Dynamic

Reconstruction methods: CLEAR
SENSE - sensitivity encoding

TR - repetition time
TE - echo time

---

Quality Control Issues

http://dnl.ucsf.edu/users/dweber/dweber_docs/mri_quality.html

---

Tissue Parameters

http://www.bic.mni.mcgill.ca/brainweb/tissue_mr_parameters.txt

---