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Ultrasonography of the Bladder and of the Prostate
The indications for ultrasonography of the bladder are comparable to the indications for renal ultrasound, in addition urinary incontinence and dyspareunia.
The examination requires a filled bladder. The transducer used for bladder ultrasound is a sector or curved array probe with 3.5–5 MHz. The bladder is systematically examined in the longitudinal (sagittal) and transverse plane. At the end of the examination, the postvoid residual (PVR) urine volume is determined, if the patient reports lower urinary tract symptoms.
The urinary bladder is an echo-free filled hollow organ, but often ultrasound artifacts mimics echogenic structures in the urinary bladder (reverberations or side lobe artefacts). The filled bladder has a echogenic wall which is sharply defined and without any wrinkles or bulges. In the area of the trigonum, the ureteral orifices and the bladder neck can be recognized. Depending on the size of the prostate, the middle lobe protrudes into the urinary bladder and may be misinterpreted as a bladder tumor.
Bladder wall thickness:
The bladder wall should be measured with a filled bladder (greater than 50% of the capacity) on the anterior wall of the bladder. In children, values above 2.5 mm are pathological and suspicious for subvesical obstruction. In adults, 7 mm is the upper limit for urinary bladder wall thickness.
Postvoid residual volume (PVR):
After micturition, the length, width and height [cm] of the bladder are recorded in sagittal and horizontal planes [fig. postvoid residual volume]. The postvoid residual volume is calculated using the formula:
Postvoid residual volume (PVR) = Length × Width × Height × 0,5
Various factors ranging from 0.5–0.7 are found in the literature. Depending on the bladder shape, considerable inaccuracy is possible. Normally there is no residual urine. PVR volumes over 100–ml are considered significant in adults. In children, a PVR volume exceeding 10% of the urinary bladder capacity is pathological (Riedmiller et al, 2001). Please see the following table for the differential diagnosis of PVR.
|DD urinary retention|
|Diseases of the prostate||Benign prostatic hyperplasia, prostate cancer, bladder cancer, bladder stones, bladder neck sclerosis, detrusor sphincter dyssynergia (DSD).|
|Diseases of the urethra||Urethral strictures, urethral valves, female urethral cancer and male urethral cancer, foreign bodies, phimosis.|
|Diseases of the urinary bladder||Neurogenic bladder disorders, drugs (anticholinergic drugs, neuroleptics), pelvic surgery, diabetes mellitus.|
Transabdominal Ultrasonography of the Prostate
The prostate is scanned through the filled bladder. After determining the length, width and height in two planes, the volume is calculated using the formula prostate volume = Length × Width × Height × 0.5. The transabdominal measurement method offers advantages in very large prostate glands due to the larger field of vision [fig. transabdominal prostate ultrasound]. In addition, transabdominal ultrasonography of the prostate easily identifies enlarged median lobes or prostatic cysts.
|Ureter ultrasound||Index||Penis ultrasound|
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
- Singer u.a. 2006 SINGER, Eric A. ; GOLIJANIN, Dragan J. ; DAVIS, Robert S. ; DOGRA, Vikram:
- What’s new in urologic ultrasound?
In: Urol Clin North Am
33 (2006), Aug, Nr. 3, S. 279–286
Deutsche Version: Sonographie der Harnblase