hypoechogenic

In contrast, tissues with lower echogenicity are called "hypoechogenic" and are usually represented with darker colors.

Acta Orthop Scand 1997 Apr;68(2):170-5 We evaluated biopsy specimens from the Achilles tendon in 40 patients with long-standing achillodynia and an ultrasonographic widened tendon with hypoechogenic areas.

There is increased sensitivity to radioiodine therapy in thyroids appearing on ultrasound scans as more uniform (hypoechogenic), due to densely packed large cells, with 81% later becoming hypothyroid, compared to just 37% in those with more normal scan appearances (normoechogenic).