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| MRI Basics
an oversimplified table |
 | Radio frequency (RF) pulse is applied to Protons in a tissue, and excites
the proton. |
| When proton returns to the equilibrium state, they emit energy as RF
signal. |
| These RF signal are picked up and analyzed. |
| By varying the sequence of RF pulse applied & collected, different
types of images are created. |
| On the scan:
 | Dark means low signal collected |
| Bright means high signal collected |
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| T1 weighted Images |
| Dark color represents |
Bright represents |
| Water: CSF, edema |
| Calcium |
|
| Lipid |
| Gadolinium |
|
| T2 weighted images |
| Dark |
Bright |
| Calcium, bone |
|
| CSF, water, edema |
|
| Gradient
Echo T2 weighted images |
| Dark |
Bright |
| |
| Flow related enhancement |
|
| Hematoma on MRI |
| |
T1 |
T2 |
| Acute |
|
| Bright rim (intact RBC & edema) |
| Dark core (deoxyhemoglobin) |
|
| Subacute |
| Bright rim (methoglobin) |
| Dark to bright core (methomoglobin) |
|
|
| Chronic |
|
| Dark rim (hemosiderin) |
| No edema (no bright rim) |
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| Further reading |
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