Advances in Environment, Biotechnology and Biomedicine
Prostate Volume Measurement Using Transabdominal Ultrasound Scanning NG KENT HOO, MUHAMMAD AKMAL AYOB, MAHEZA IRNA MOHAMAD SALIM, HEAMN NOORI ABDULJABBAR, EKO SUPRIYANTO Faculty of Health Science and Biomedical Engineering Universiti Teknologi Malaysia 81310, Skudai Malaysia
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[email protected] Abstract: Prostate volume measurement is frequently used to diagnose the abnormalities of the prostate. Abnormal enlargement of the prostate may be due to inflammation or virus infection. In a more severe case, the abnormal enlargement may indicate prostate cancer. The measurement of the prostatic gland is commonly performed by using transrectal scanning. However, this scanning method causes uncomfortable feeling. Therefore, this study proposes the use of transabdominal scanning in the measurement of prostatic volume. The subjects are requested to fully fill their urinary bladder to obtain clear prostatic gland images. The measurement is done by computing the ellipsoid formula which calculates the size by multiplying the largest anteroposterior height (H), transverse width (W), cephalocaudal length (L) and diameters by . The quality of the images is then enhanced by using a series of image processing. The findings show that the prostate size is affected by body size, which means weight and height. Key-words: - Prostate size, ellipsoid formula, anteroposterior height, transverse width, cephalocaudal length, diameter, body size.
will continuously grow as the age increase for most of the male’s life. The American Cancer society found that prostate cancer is one of the most common cancers affecting the older men in developed countries [3]. It is getting a serious attention from the world as it has become a significant cause of death for elderly men.
1 Introduction Prostate is a compound tubuloalveolar exocrine gland of the male reproductive system. The function of prostate is to secrete slightly acidic fluid, which has the characteristic of milky or white in appearance. The secretion usually constitutes 20% to 30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. In medical practice, most of the prostate abnormalities are diagnosed by measuring their volume [2]. Normally, the prostate volume range has the size of 250 at birth to 100000 sized at
2 Problem Background Since prostate cancer highly leads to death in elderly men population, it is very important to have a good diagnostic method to measure
puberty. After puberty, the prostate volume
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the prostate volume. Magnetic resonance imaging (MRI) with an endorectal coil and prostate-specific antigen (PSA) are the most frequently used modality in the prostate volume measurement [4]. Unfortunately, MRI scanning is very time consuming. Therefore, ultrasound has been proven to be the safest and fastest imaging modality. There are several available approaches in ultrasound scanning like transabdominal, transperineal and transrectal scan routes [5]. This study proposes the transabdominal scanning for measuring prostatic volume.
Fig. 1. Prostatic gland [1]
Previous researches on the prostate volume only focused on the subjects’ ages [6]. However, that is not the only factor that affects the volume of prostate, as parameters like body weight and height contribute a lot in the differences of prostate size.
3.2 Size and Measurement 3.2.1 Transrectal Ultrasound Transrectal ultrasound is a short test that uses ultrasound waves to create an image of the prostatic gland. The test is performed by placing a small and lubricated probe into the rectum. The probe transmits ultrasound waves which create echoes as they enter. The processing unit will receive the echoes that are bounced back and the pattern of echoes will be translated into an image of the prostatic gland [10].
3 Literature Review 3.1 Prostate Anatomy A healthy human male prostate has the . The prostate is volume of 100000 located above the base of the penic and below the urinary bladder and backs into the front wall of rectum. The prostate evolves in this tight-wedged position to aid reproduction. The prostate secretes some of the fluid for semen, stops urination during ejaculation, and enhances sexual pleasureable sensations [7]. Figure 1 shows the anatomy of prostate.
Since mid-1950s, the transrectal route has been introduced for fingerguided prostate biopsy (PBx)[9]. Transrectal route has become the gold standard after Hodge demonstrated higher detection rates for the sextant transrectal ultrasound-guided PBx than sextant finger-guided analog sampling [10]. The transrectal method provides a clear image of organs in the pelvis. Normally, transrectal ultrasound is used for the evaluation of the prostate gland with elevated prostate specific antigen (PSA) or prostatic nodules on digital rectal exam [10].
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width (W), cephalocaudal length (L) and diameters by [11].
3.2.2 Transabdominal Ultrasound Transabdominal ultrasound is a type of medical ultrasonography used to visualise the structures of abdominal anatomy. The transmitted and reflected ultrasound waves visualize the organs through the abdominal wall. The advantages of transabdominal ultrasound are the procedure can be performed quickly, bed-side, not radiated and non invasive [11].
L
W H
4 Methodology
Fig. 2. Prostate parameters.
4.1 Subjects
4.4 Image Processing
In this study, 10 subjects from age of 20 years old to 25 years old were selected to undergo the transabdominal scanning. The subjects were randomly selected with different heights and weights. The subjects were the students whom do not have any bad habits like smoking and drinking.
The image processing stage was conducted using MATLAB. Further processing is required since the obtained images from the scanning would contain not only prostate, but also urinary bladder and noises. Therefore, noise elimination and segmentation of prostate are important to obtain the desired images. The coding of the overall procedures is shown in the Appendix. By taking an example of the image obtained from the scanning, the segmentation could be done in the few steps.
4.2 Prostate scanning Toshiba Aplio MX was used in the research for prostate scanning. The device was set to a 2D mode and 8 MHz convex transducer was used as the probe. The subjects were instructed to fill their urinary bladder by consuming water. This was done to make sure the prostate could be well-seen under full urinary bladder condition. If the urinary bladder was not fully filled or empty, the prostate images obtained in the scanning would not have a good shape.
size
measurement’s
4.3 Prostate size measurement Transabdominal scanning method is used in this research. The ellipsoid formula was used to calculate the size by multiplying the largest anteroposterior height (H), transverse
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Fig. 3. The procedure of image segmentation. By using the cropping tool in MATLAB, the desired region was cropped, which was the prostate’s region. The image obtained from
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the scanning was not clear and contained a lot of noises. Therefore, a filter tool was needed to de-noise the image. The filter chosen in the study was median filter, which was used to smoothen the image and reduce the noises. The next step was to convert the image from “rgb” format into “bw” format. This process is very important for the edge detection step. However, the detected edges contained unwanted information too, that came from urinary bladder. To eliminate these edges, we used “bwareaopen” to eliminate the areas which were less than 50 pixels. Finally, the image was morphed with the original image.
79
31.8
29.4
23.4
75
32.2
29.9
20.0
74
29.4
27.7
23.2
55
28.9
27.3
19.4
7 11454 .8 10082 .2 9892. 6 8014. 2
5 Results and Analysis
Table 2. Parameter of measurement and comparison. Sujbect Weight Height Prostate (kg) (m) Size ( 1 70 1.68 9563.5 2 77 1.76 10864.6 3 57 1.63 8456.6 4 82 1.80 11686.7 5 62 1.64 8941.4 6 68 1.64 9781.7 7 79 1.78 11454.8 8 75 1.74 10082.2 9 74 1.74 9892.6 10 55 1.62 8014.2
There are 10 subjects who participated in this project from the age of 23. The prostate size measurements are shown in the table below.
The data collected were then plotted into a graph to observe the relationship of the prostate size with the body weight.
The purpose of using the segmentation tool for the images is because the comparison of the shapes of prostate is needed for the study. Therefore, segmentation was needed to isolate prostate from the urinary bladder, so that the comparison of the images could be done in an easy way.
Table 1. Prostate size measurement subjects with diffent body weight. Subj Anteropo Trans Cephal ects sterior verse ocaudal Wei height width length ght (H) (mm) (W) (L) (kg) (mm) (mm) 70
30.2
28.8
21.0
77
31.1
27.8
24.0
57
29.9
25.6
21.1
82
31.0
30.0
24.0
62
29.9
28.7
19.9
68
32.0
27.8
21.0
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of 10 Prosta te size ( ) 9563. 5 10864 .6 8456. 6 11686 .7 8941. 4 9781.
Fig. 4. Graph of prostate volume and body weight.
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The graph shows the relationship between the prostate size and the body weight of a male. Normally, the prostate size would show an increment if the age of a male increases. However, in this research, it was found that the body weight and the body size also affected the prostate size. A man with heavier body weight compared to a lighter one will have a larger prostate size. Body fat of a person will reflect the relationship of human growth and development, with the environment under the influence of a person’s genotype. The study shows that even the subjects from the same age will not have the same prostate size.
Subject Weight Height (kg) (m)
1 2 3 4 5 6 7 8 9 10
70 77 57 82 62 68 79 75 74 55
1.68 1.76 1.63 1.80 1.64 1.64 1.78 1.74 1.74 1.62
Body Mass Index (BMI) 24.80 24.86 21.45 25.31 23.05 25.28 24.93 24.77 24.44 20.96
Prostate Volume ( 9563.5 10864.6 8456.6 11686.7 8941.4 9781.7 11454.8 10082.2 9892.6 8014.2
In this research, the correlation of weight and height was computed by calculating the body mass index (BMI). In order to obtain the trend of correlation, the graph of BMI and prostate size is plotted in Fig. 6.
Fig. 5. Graph of prostate volume and height. Fig. 4 shows the relationship between the prostate size and the subjects’ height. The graph shows that with the increase of height, the prostate size will also increase. There were some special cases, where there were two subjects with the height of 1.64 m, but the prostate sizes did not show a similar value. The reason of this difference was due to the different weight of the subjects. Therefore, the hypothesis is made due to this figures, the weight of the subject is the main factor that affect the prostate size.
Fig. 6. Graph of prostate volume and BMI. The graph shows that prostate volume would increase if BMI was greater. Therefore, a hypothetical formula was made from the graph.
6 Discussion Table 3. Correlation of weight, height and prostate size.
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Table 4. Increment of prostate volume based on the differences of height and weight.
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[2] Evelyn L.M. Ho, Prostate size: Is size all that matters?, 2010, pp. 1-3. [3] Marx FJ & Karenberg A, History of the Term Prostate, Prostate, 2009, 208-213. [4] Roehrborn CG, Girman CJ, Rhodes T etal., Correlation between prostate size estimated by digital rectal examination and measured by transrectal ultrasound, Urology, 1997, 548–57. [5] Martha K. Terris, Comparison of Ultrasound Imaging in Patients undergoing transperineal and Transrectal Prostate Ultrasound, Urology, Vol.52, 2009, 1070-1072. [6] Firas Abdollah, Trans-rectal Versus Trans-Perineal Saturation Rebiopsy of the Prostate: Is There a Difference in Cancer Detection Rate?, Urology, Vol.77, 2011, 921-926. [7] Patel AR, Jones JS, Optimal biopsy strategies for the diagnosis and staging of prostate cancer, Curr Opin Urol., 2009,232-237. [8] Scattoni V, Raber M, Abdollah F, et al., Biopsy schemes with the fewest cores for detecting. 95 % of the prostate cancers detected by a 24-core biopsy, Eur Urol. 2009, 1-8. [9] Antonio Galfano, Prostate Biopsy: The Transperineal Approach, European Association of Urology, Vol.5, No.X, 2007, pp. 241-249. [10] Scattoni V, Zlotta A, Montironi R, et al., Extended and saturation prostatic biopsy in the diagnosis and characterisation of prostate cancer: a critical analysis of the literature, Eur Urol. 2007, 1309- 1322. [11] Walz J, Graefen M, Chun FK, et al., High incidence of prostate cancer detected by saturation biopsy after previous negative biopsy series, Eur Urol. 2006, 498-505. [12] Emiliozzi P, Corsetti A, Tassi B, et al., Best approach for prostate cancer detection: a prospective study on transperineal versus transrectal six-core prostate biopsy, Urology. 2003,961-966.
Increment of Increment of Increment of Height (m) Weight (kg) Prostate Volume ( 0.01 2.0 442.40 0.01 8.0 905.05 0.04 5.0 201.45 0.06 4.5 423.90 0.02 2.5 877.00 0.02 2.0 590.20 0.02 3.0 231.90 By rearranging the height of the subjects from the lowest to the highest, the increment of the prostate volume could be obtained. From the table, the prostate volume increased with the increment of height. However, the height of the subjects was not the only factor which affected the prostate volume. From the table, the first increment of 0.01 m contributed 442.40 of the increment of prostate volume while the second increment of 0.01 m affected the prostate volume by . This was due to the difference 905.05 of the increment of weight. For the same height increment, the prostate volume was controlled by the weight of the subjects.
7 Conclusion The results show that ultrasound is an easy and safe way to measure the prostate size. From the results, we can conclude that the size of prostate is larger for a man with larger body size. Also, it is suggested that another research is needed for computation to obtain the standard prostate size comparison which not only focuses on the age but also considers the body size of a man. It may help the researchers who intends to examine the prostate size analysis. Reference: [1] Prokar Dasgupta, ABC of Prostate Cancer, 2012.
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