T2* sequence
Pronunciation: tee-two-star
MRI sequence sensitive to local magnetic field inhomogeneities, particularly useful for detecting hemorrhage.
Full Definition
T2* (T2-star) sequence, also known as gradient echo sequence, is an MRI technique that measures T2* relaxation, which includes both T2 relaxation and additional dephasing from local magnetic field inhomogeneities. This sequence is highly sensitive to the presence of blood products, particularly deoxyhemoglobin and hemosiderin, which create local magnetic field disturbances and appear as signal dropout or 'blooming' artifacts. T2* sequences are essential in neuroimaging for detecting acute and chronic hemorrhage, microbleeds, calcifications, and iron deposition. The technique is faster than conventional T2 sequences but more susceptible to artifacts from patient motion and metallic objects.
Usage
Usage note: Use asterisk (*) not word 'star' in formal writing; hyphenate T2-star in adjectival use.
In Context
- "The T2* sequence revealed multiple cerebral microbleeds consistent with chronic hypertensive changes." — Diagnostic findings
- "T2* imaging showed characteristic blooming artifact from the hemorrhage that was less apparent on T2-weighted images." — Sequence comparison