Correlations between the various methods of estimating prostate volume: transabdominal, transrectal, and three-dimensional US.
OBJECTIVE
To evaluate the correlations between prostate volumes estimated by transabdominal, transrectal, and three-dimensional US and the factors affecting the differences.


METHODS
The prostate volumes of 94 consecutive patients were measured by both transabdominal and transrectal US. Next, the prostate volumes of 58 other patients was measured by both transrectal and three-dimensional US. We evaluated the degree of correlation and mean difference in each comparison. We also analyzed possible factors affecting the differences, such as the experiences of examiners in transrectal US, bladder volume, and prostate volume.


RESULTS
In the comparison of transabdominal and transrectal US methods, the mean difference was 8.4 +/- 10.5 mL and correlation coefficient (r) was 0.775 (p < 0.01). The experienced examiner for the transrectal US method had the highest correlation (r = 0.967) and the significantly smallest difference (5.4 +/- 3.9 mL) compared to the other examiners (the beginner and the trained; p < 0.05). Prostate volume measured by transrectal US showed a weak correlation with the difference (r = 0.360, p < 0.05). Bladder volume did not show significant correlation with the difference (r = -0.043, p > 0.05). The comparison between the transrectal and three-dimensional US methods revealed a mean difference of 3.7 +/- 3.4 mL and the correlation coefficient was 0.924 for the experienced examiner. Furthermore, no significant difference existed between examiners (p > 0.05). Prostate volume measured by transrectal US showed a positive correlation with the difference for the beginner only (r = 0.405, p < 0.05).


CONCLUSIONS
In the prostate volume estimation by US, experience in transrectal US is important in the correlation with transabdominal US, but not with three-dimensional US. Also, less experienced examiners' assessment of the prostate volume can be affected by prostate volume itself.
Kim
Sun Ho
SH
Department of Radiology, DongGuk University International Hospital, Goyang, Korea. kimsh@duih.org
Kim
Seung Hyup
SH
D000328:Adult; D000368:Aged; D002983:Clinical Competence; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*; D001743:Urinary Bladder / Q000000981:diagnostic imaging