Answers are grounded in this paper and cite their sources.
Twenty observers estimated renal cortical brightness compared with the liver in 28 ultrasound images. Their judgment was compared with objective densitometer readings. High inter- and intra-observer variation was found. Estimates of brightness of ultrasound images by eye alone should be interpreted with care.
No takes yet. Share an insight, caveat, or question.
Lamont et al. (1990) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: