Transrectal ultrasonography TRUS
In urology, ultrasound waves were first used to detect renal stones during surgery
Since the introduction of the prostate-specific antigen (PSA) screening test and
early detection of prostate cancer, the role of transrectal ultrasonography (TRUS)
has changed; it is mainly used to visualize the prostate and to aid in guided
needle biopsy. TRUS has become an extension of the urologist s finger in
the early detection of prostate cancer. .
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Internal Architecture and Anatomy of the Prostate
the prostatic urethra, which is the main reference point of the prostate, divides the gland into
an anterior fibromuscular stroma and
a posterior glandular organ.
The urethra angulates 35° anteriorly in the proximal portion of the prostate. T
he ejaculatory ducts run in the same plane as the distal prostatic urethra to join the verumontanum.
The prostate has 4 glandular zones, each with their own ductal system. The peripheral zone, transition zone,
Peripheral zone
The peripheral zone constitutes almost 75% of the normal prostate gland.
It occupies the distal prostate gland, the area around the urethra distal
to theverumontanum. Approximately 70% of carcinoma of the prostate (CAP)
cases arise in this zone.
Central zone
The central zone constitutes 25% of the normal prostate
and occupies the part of the prostate behind the proximal
prostatic urethra. The ejaculatory ducts traverse through
the central zoneThe central zone is embryologically distinct
from other zones and is derived from the mesonephric system (wolffian).
Approximately 5-10% of CAP cases arise in this zone.
Transition zone
The transition zone makes up approximately 5-10% of the normal prostate gland
. The transition zone lies on either side of the proximal prostatic urethra
lateral to the internal sphincter
The transition zone is where benign prostatic hyperplasia (BPH) originates,
and approximately 20% of CAP cases arise in the transition zone.A
Periurethral glands
The periurethral glands comprise less than 1% of the glandular tissue.
These glands are embedded in the smooth muscle of the prostatic sphincter.
This is the site of origin of the large median lobe of BPH.
Preparation, positioning, and contraindications
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More than 80% of urologists administer an enema prior to transrectal ultrasonography (TRUS)
and prostate biopsy, but some authors feel this is unnecessary. More than 90% of urologists
administer oral agents for prophylactic antibiotic coverage
A total of 11 different antibiotics with 20 different dosages and durations of treatment
, ranging from 1-17 days, have been reported. Increasing support has been garnered for
single-dose prophylaxis in patients with uncomplicated medical conditions
A fluoroquinolone antibiotic prior to the procedure and a second dose 12 hours
later is the protocol most commonly recommended for antibiotic coverage
Positioning
should be left lateral, lithotomy, or knee-elbow
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .