Prostate Flashcards
What structure is superior to the prostate?
Bladder
What structures does the prostate surround?
Neck of the bladder and the urethra
What does the prostate lie posterior to?
P.S
What structure does the prostate lie anterior to?
Rectum
What muscles lie posterolateral to the prostate?
Levator ani muscles
Does the prostate have a capsule?
It has a fibrous capsule- not a true capsule
What is the shape of the prostate?
Ovoid inverted pyramid
What is the orientation of the prostate?
Apex- inferior or caudal end
Base- superior or cephalic end
What is the size of the prostate? (L, W and H)
Length: 3.0-3.5cm
Width: 4cm
Height: 2.0-2.5cm
What is the weight of the prostate in younger men? (Up to 50 years)
20 grams (cc)
What is the weight of the prostate in older men? (Over 50 years)
Less then 40 grams
What is the physiology of the prostate?
Fibromuscular and glandular tissue
What is the purpose of producing and secreting an alkaline fluid? (2)
- Aids in motility and activating sperm
2. Neutralizes the acid environment of vagina, uterus and Fallopian tubes
How much alkaline fluid is included in the semen volume?
1/3 of semen volume
What antigen does the prostate produce?
PSA- prostate specific antigen
What happens to the PSA volumes as the male ages?
Increases with age
How many zones are there in the prostate?
4
The prostate zones are positioned based on what structures?
Urethra and ejaculatory duct
What is zonal anatomy useful in detecting?
Localization of cancer
What is the zonal anatomy based on?
Histology also components
What are the zones of the prostate?
- Peripheral zone
- Transitional zone
- Central zone
- Periurethral glands
What zone of the prostate is the largest?
Peripheral zone
What is the most common site of prostate cancer?
Peripheral zone
What structure does the peripheral zone surround?
Distal urethra
How is the peripheral zone seperated from the transition and central zone?
Surgical capsule
What regions of the prostate does the peripherial zone occupy?
Posterior, lateral and apical regions
Does BPH affect the peripheral zone?
No
What % of prostatic glandular tissue is included in the transitional zone?
5%
Where is the transitional zone located on the prostate?
Two small glands on each side of the prox urethra
What zone is the common origin of benign prostatic hyperplasia?
Central zone
Where do the ducts end in the transition zone?
Proximal urethra at the level of the verumontanum
What % of prostatic glandular tissue is included in the central zone?
25%
Where is the central zone located?
Base of the prostate
What structures enter the central zone?
Ducts of the vas deferens and seminal vesicles
What structure passes through the central zone?
Ejaculatory duct
Is the central zone prone to diseases?
No, relatively resistant to diseases
Where does the central zone terminate?
Near the verumontanum
What is the verumontanum?
Area where the ejaculatory duct joins urethra
How much prostatic glandular tissue does the periurethral glands include?
1%
Where are the periurethral glands located?
Embedded in the longitudinal smooth muscle of the proximal urethra
What is the periurethral gland know as?
“Internal prostatic sphincter”
What is the function of the internal prostatic sphincter?
Prevent reflux of urine
What is the fibromuscular stroma?
Non glandular area on anterior surface of the prostate
Smooth muscle and connective tissue
The fibromuscular stroma makes up how much of the prostate?
1/3 of the prostate
What zones does the outer/peripheral gland of the prostate make up?
Peripheral and central zones
What zones does the inner glans of the prostate make up?
Transitional zone, fibromuscular storm and urethral sphincter
What is the shape of the seminal vesicles?
Paired, ovoid shape
Where do the seminal vesicles sit in relation to the bladder?
Posterior
Where do the seminal vesicles sit in relation to the prostate?
Superior
What 2 structures join to form the ejaculatory ducts?
SV and vas deferens
What are the dimensions of the seminal vesicles?
L: 3-4cm
AP (thickness): 1-3cm
What factors cause the seminal vesicles to vary in size and shape?
Age and sexual activity
What do the seminal vesicles secrete?
Alkaline, viscous fluid into the ejaculatory duct which contributes to sperm viability
What are some indications for an US?
- Positive DRE
- Increased PSA
- Urinary frequency, nocturia, decreased urine stream
- Male infertility
- Biopsy guidance
- Blood or pus in the urine or semen
What are the 2 methods used to scan the prostate and seminal vesicles?
- Transabdominal (transvesicular)
2. Transrectal (TRUS)
What is TA US useful in assessing?
Size and volume of prostate only
What is pt prep for scanning the prostate?
Full bladder
What is the TA US appearance of the prostate?
Ovoid structure
Low to moderate echogenic levels
Homogenous
Echogenic interface due to the urethra
What is the TA US appearance of the seminal vesicles?
Hypoechoic, medium to low level echotexture
What are the different type of TRUS probes?
Axial or biplane, side-firing or end-firing
What is the most common TRUS probe?
End-firing
Describe the end-firing TRUS probe
Allows for multi-plane imaging
Convenient, easy to use
Biopsy capability at the time of examination
What is the frequency used with the TRUS probes?
7-10 MHz
What is the pt position for a TRUS exam?
LLD, with legs bent to chest
What is the pt prep prior to a TRUS exam?
DRE
What is the scan orientation of the TRUS exam?
Rectum at the bottom of the screen
Sagittal- anterior abdominal wall at the top and puts head on the left side
Transverse- anterior abdominal wall at the top of image
What is the sonographic appearance of the peripheral zone?
Homogeneous, isoechoic
What is the sonographic appearance of the surgical capsule?
Separates the PZ and CZ
Hypoechoic line
What is the sonographic appearance of the central zone?
Hyperechoic or isoechoic to the PZ
What is the sonographic appearance of the transition zone?
Isoechoic to the PZ
Hypoechoic to the BPH
Echogenic foci
What is another name for echogenic foci?
Corpora amylacea
What are corpora amylacea?
Protein deposits
What is the sonographic appearance of the periurethral glandular area?
Hypoechoic
Blends with urethra
Prominent in young men
What is the sonographic appearance of the anterior fibromuscular stroma?
Hypoechoic
What area is used as a standard for echogenicity in the prostate?
Peripheral zone
What is the sonographic appearance of the seminal vesicles?
Hypoechoic, symmetrical
What is the measurement of the seminal vesicles?
10mm AP
What are the 4 different lab tests used to identify function of the prostate?
- Prostate specific antigen (PSA)
- PSA density
- Acid phosphatase
- Alkaline phosphatase
What enzyme is made specifically by the prostate?
PSA
Where is PSA created and deposited?
Through ducts in the prostate
When is PSA elevated?
BPH, infection or carcinoma
Is PSA specific to cause?
No
What are the normal values of PSA?
< 4ng/ml
What fraction of men have an increased PSA but do not have cancer?
2/3
What is PSA density?
PSA level/prostate volume
Density of > 0.12 warrants what type of procedure?
Biopsy
Where is acid phosphatase found?
In prostate and semen in high concentrations
What causes increased levels of acid phosphatase?
Carcinoma that has spread beyond prostate capsule
Where is alkaline phosphatase produced?
Osteoblasts
When will levels of alkaline phosphatase increase?
Increase in osteoblastic activity
Is elevation of alkaline phosphatase specific to prostatic cancer?
No, associated with bony metastases
What vessels supply blood to the prostate?
Prostaticovesical arteries
What is benign ductal ectasia?
1-2mm tubular structures in the peripheral zone
What is the US appearance of benign ductal ectasia?
Hypoechoic
What can benign ductal ectasia be mistaken for?
Prostatic cancer
How does the appearance of benign calcifications appear compared to malignant calcifications?
Benign appear courser
