Validation of canine prostate volumetric measurements in computed tomography determined by the slice addition technique using the Amira program

Abstract

BackgroundProstatic diseases are common and mostly associated with enlargement of the accessory gland. Thus, determining the prostate size has become a main criterion for evaluating prostate health status. Computed tomography (CT) is recommended as a beneficial tool for evaluating prostate size, morphology and surrounding tissues. The purpose of this study was to establish an accurate procedure for volume estimation and afterwards evaluate the prostate volume in CT. Data of 95 dogs were analysed (58 male intact, 37 male neutered) using the slice addition technique with the Amira program. Accuracy of volumetric measurements by CT was validated by comparing them with those of phantoms of known volume. Patients were grouped according to age (< 4 yrs., 4–8 yrs., > 8 yrs) and prostate morphology in CT (H = homogeneous, I = inhomogeneous, C = cystic). The length of the sixth lumbar vertebra was measured to relate prostate volume to body size. This ratio was generated to compare prostate volume between the groups, irrespective of body size (ratio volume = Rv).ResultsA high correlation between the CT-derived and phantom volume was found. Overall, the mean prostate volume was 58.6 cm3. The mean ratio volume was 1.3 in intact male dogs, this being significantly higher than in neutered dogs (0.7). The lowest ratio volume values were found in group H for intact (Rv = 0.9) and neutered dogs (Rv = 0.6), followed by group I (intact: Rv = 1.1; neutered: Rv = 0.7) and C (intact: Rv = 1.4; neutered: Rv = 0.8). The length of the sixth lumbar vertebra was well correlated with the prostate volume (intact: r = 0.63, p < 0.001; neutered: r = 0.48, p = 0.003), while age exhibited a correlation only in intact dogs (r = 0.52, p < 0.001).ConclusionThe present study is pioneering in applying a slice addition technique to volumetric measurements of the prostate gland in CT, resulting in a highly precise method. Volumetric measurements of the canine prostate gland in CT images provide information about the prostate structure, castration status, age and body size of the patients. Therefore, prostate volume is a relevant parameter for evaluating prostate health status.Electronic supplementary materialThe online version of this article (10.1186/s12917-019-1778-z) contains supplementary material, which is available to authorized users.

Evaluation of canine prostate volume in calculated tomographic images - comparison of two assessment methods

“…The mean volume measured by the Formula method was 41.3 cm 3 (± 141.4 cm 3 , ranging from 0.5 to 1319.8 cm 3 ) and the mean volume measured by the Wrap function was 59.8 cm 3 (± 188.7 cm 3 , ranging from 1.3 to 1579.2 cm 3 ). The SAT prostate volume values had been obtained from a previous study investigating the same dogs [5]. The mean SAT prostate volume was 58.6 cm 3 (± 188.6 cm 3 , ranging from 0.6 to 1600.5 cm 3 ).…”

“…Moss et al hypothesised that evaluation of volume provides a more accurate measurement of the organ’s size (canine liver, kidney, spleen) than measuring the organ’s length and width [16]. In a previously published paper, volumetric measurements provided more information on prostatomegaly than single dimensional parameters were able to [5]. Furthermore, it could be shown that analysing prostate volume exhibited the potential to demonstrate prostatic alterations caused by castration, age, body size and different prostatic structures.…”

“…Thus, volumetric measurements, combining single dimensional parameters might be advantageous for diagnosing prostatic enlargement. Determining prostatic volume was reported to be an accurate method for describing alterations in prostatic size and helpful for differentiating between different prostatic alterations [5]. The volume of cystic prostates was significantly higher compared to that of homogeneously structured prostates in computed tomography (CT) images.…”

“…Nevertheless, measurements of the prostate gland were not included in their study. A previously carried out study by Haverkamp et al applied this technique to measure the volume of the canine prostate gland for the first time [5]. Comparison of SAT measurements to real volumes of different phantoms and cadaver prostates exhibited a high accuracy with a variation of ±0.8% to real volume.…”

“…On the one hand, the accuracy of these volumetric measurements was validated with phantoms and cadaver prostates with known volume. On the other hand, measurements were compared to SAT measurements of the same images carried out in a previous study [5]. Since the different size and surface structure of the prostates may have an impact on the accuracy of measurement methods, CT data should be evaluated taking different categories of prostatic sizes as well as the castration status of the dogs and the prostate tissue structure into consideration.…”