Prostate

Prostate


INTRODUCTION


A gram of prostate tissue is equivalent to 1 milliliter of volume; hence, volume could be converted to weight.


Prostate: Chestnut shaped, homogeneous, and hypoechoic gland with <5 milliliters in size up to 12 years.


Seminal vesicles: Paired, hypoechoic structures cephalad to the base of the prostate; usually ~1 centimeter front to back.


Zonal anatomy


Four glandular zones surround the prostatic urethra:


1.    Peripheral zone (PZ)—70% site for most prostatic cancers.


2.    Transitional zone (TZ)—5% site of origin of benign prostatic hyperplasia (BPH).


3.    Central zone (CZ)—25% relatively resistant to disease process. Only 5% cancers start here.


4.    Periurethral area—1% internal prostatic sphincter.


On USG, it is difficult to identify these zones in normal prostate and only two zones are identified.


Outer gland: Peripheral (PZ + CZ)


Inner gland: (TZ + anterior fibromuscular stroma + internal urethral sphincter)


Both outer and inner glands are separated by a surgical capsule.


Neurovascular bundle lies bilaterally along the posterolateral aspect of the prostate and is a preferential pathway of tumor spread.


Corpora amylacea, seen as echogenic foci, develop along the surgical capsule and periurethral glands (proteinaceous debris in dilated prostatic ducts).


Measurements (Figure 11.1)


Maximal transverse width (T): Right to left


Anteroposterior (AP): Anterior midline to rectal surface


Length (L): Maximal head to foot


Volume is calculated by the formula


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Nov 6, 2018 | Posted by in ULTRASONOGRAPHY | Comments Off on Prostate
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