What it means
MRI builds pictures from signals given off by tissues, and each sequence (image type) shows them in its own shades of gray. Hypointense means a spot gives off less signal than its surroundings, so it looks darker. On T1 images, fluid and swelling are usually dark. On T2 images, calcium, dense scar-like tissue, iron left by old bleeding, air and fast-flowing blood tend to be dark.
When it matters
On its own, hypointense does not mean harmless or harmful. Many dark areas are benign (not cancer), such as fibroids, which are common muscle growths in the uterus, or small calcium deposits. The radiologist combines all the sequences, the size and shape, and any uptake of contrast. When the meaning is unclear, comparison with older scans or a follow-up MRI is common.
Questions to ask your doctor
- On which type of image is the area dark?
- Could the darkness come from calcium, scar tissue or old blood?
- Does it need a follow-up MRI or comparison with older scans?
