McLean G K, Edell S L
Radiology. 1978 Jul;128(1):181-2. doi: 10.1148/128.1.181.
Gray scale ultrasonography was used to measure bladder volumes. A high degree of accuracy (r = 0.097) in correlating volumes with instilled volumes is attributed to the inherently greater accuracy of gray scale as compared to bistable B-mode scanning.