The Relationship between Ultrasonic Volume and Actual Weight of Pathologic Uterus

Abstract

Our purpose was to assess the correlation between the estimated volume based on ultrasonic measurement in vivo and the actual weight of the diseased uterus after hysterectomy, and then retrospectively tried to establish a simple equation to convert the volume into the weight in grams. A total of 105 women with nonmalignant diseased uteri which were prepared to undergo laparoscopy-assisted vaginal hysterectomy had had preoperative ultrasound scanning to estimate the uterine size by measuring three dimensions including the length (L), width (W) and anteroposterior (AP) diameter. The uterine volume was calculated by the use of a prolate ellipsoid formula (4/3 × ∏ × L/2 × W/2 × AP/2). Actual uterine weight was immediately taken after extirpation of the uterus. Linear regression analysis revealed uterine weight (g) = 50.0 + 0.71 × volume (cm³), with correlation coefficient = 0.93 and SE = 49.6 g. There was a close, positive correlation between the estimated uterine volume and actual uterine weight. With utilization of this equation, the uterine size in vivo can thus be expressed as a concrete, objective value in weight instead of ‘weeks’ size’ by comparison with pregnant uterus, which has been commonly used in traditional gynecologic practice.

The estimated volume of the fibroid uterus: a comparison of ultrasound and bimanual examination versus volume at MRI or hysterectomy

“…Additionally, transabdominal ultrasound is less reliable with obese patients. The studies of Kung and Harb [18,19] have already proved that the highest precision of measuring uterus volume can be achieved measuring the length, width and anteroposterior diameter of the uterus, as we did, and not only on total length of fibroids [27] or uterus [15]. Cantuaria showed a significant correlation between ultrasound dimensions and uterine size determined by bimanual examination and histopathology, although weight estimation was not assessed [15].…”

“…Most studies measured the uterine dimensions using abdominal ultrasound, which is less accurate than transvaginal ultrasound due to the difference in penetration depth [15,[17][18][19]24]. Additionally, transabdominal ultrasound is less reliable with obese patients.…”

“…It is uncertain how reliable and accurate bimanual and ultrasound examinations are in the assessment of uterine volume. Only a few studies have compared the uterine volume estimated through bimanual examination and ultrasound with exact uterine volumes or weights during histopathologic examination [15][16][17][18][19]. To our knowledge, no previous study has compared estimated uterine volumes of the enlarged non gravid fibroid uteri with bimanual examination and transvaginal ultrasound with MRI.…”

Evaluation of complications of abdominal and vaginal hysterectomy

“…Kung et al proved that by multiplying the three dimensions of the uterus in centimetres (length × width × antero posterior diameter at the fundus) by 0.52, physicians can estimate the mass of the uterus in grams in order to obtain a more accurate preoperative estimate of uterine size. 21 But studies done later proved that even larger uterus can be removed vaginally with least complications rate. 22 Consultant et al showed that uterus up to 600 g can be removed vaginally.…”

Prediction of operation time for laparoscopic myomectomy by ultrasound measurements

“…Several studies have been designed to convert uterine size to uterine weight by ultrasound measurement or by size estimation from pelvic examinations. Such measurements have been reported with high validity [2,12,14,23]. However, the validation of ultrasound measurement of uterine leiomyoma after myomectomy or LM has not been established.…”