Saturday, April 14, 2012

Radiographic Urethrocystography part 1


Radiographic Urethrocystography part 1

Introduction
Bead-chain cystography
Standard lateral upright and straining cystogram
Parameters of urethrocystography
Comparability of perineal ultrasound and lateral urethrocystography

Introduction
Attempts to determine the urinary continence mechanism have prompted the study of urethrovesical relationships by numerous methods, foremost among them the radiographic techniques of urethrocystography (UCG). Radiologic investigation of the female bladder and urethra has undergone many changes since its first application at the beginning of this century (Koelbl et al, 1991). Fluoroscopy was introduced in the 1920s, and chain cystography has been used extensively since the publication of Hodgkinson’s method in 1958.  Various techniques have been devised to improve demonstration of the urethra and thus its relationship to the bladder and pubic symphysis (Tsuchida et al, 1982).

Cystography seems undoubtedly useful in the overall comprehension of SUI pathogenesis (Riva et al, 1982) and UCG was advocated by various authors as the most valuable diagnostic tool to confirm GSI (Hodgkinson, 1970).  In 83.5% of women the urethrocystography study confirmed the clinical diagnosis of SUI. However this indication cannot be based on the radiological study by itself, it must in fact take into account all the other aspects of the disease (Goller et al, 1986).

Lateral urethrocystography and urodynamic assessment with the patients' medical history, the assessment of their complaints, clinical vaginal examination, and clinical stress test, they offer valuable information for an efficient therapeutic concept (Grischke et al, 1991). Imaging for the study of SUI has until recently been limited to standard radiography and fluoroscopy. More recently, sonography and magnetic resonance (MR) imaging have been used as investigative tools in the study of SUI and prolapse. These advanced techniques are enhancing our understanding of pathophysiology of incontinence, prolapse, and anatomy in living patients, advancing our existing concepts, and may eventually fine more general applicability in clinical practice (Mostwin et al, 1995). Ultrasound evaluation of the position and mobility of the urinary BN practically replaced lateral chain urethrocystography. The functional and physiological conditions of paravaginal and periurethral structures in women were assessed by physical, urodynamic and ultrasonography examinations and also by cystourethroscopy (Masata et al, 1998).

Bead-chain cystography

The placement of a radio-opaque chain of metal beads in the female urethra was the first important technique used to study urethral position and mobility. It is clear that the distinguishing topographic pathologic feature is depression of the urethrovesical junction to the lowest level of the bladder during the peak of straining effort. It is also clear that the spatial relationship of the bladder and urethra to the symphysis make no difference in either the incidence or severity of SUI (Hodgkinson, 1978).
The loss of posterior urethrovesical angle is synchronous with SUI in women (Hertogs and Stanton, 1985). Other study, however, criticized either the predictive value of the techniques or the degree of blinded inter observer variance (Mouritsen et al, 1993). Measurement of posterior urethrovesical angle (PUVA) by chain urethrocystography was neither helpful in making the diagnosis nor predictive of the recurrence of urinary dysfunction (Sumi et al, 2000).
         
          Bead-chain cystography was once the gold standard. Today, the bead-chain cystourethrogram is hardly ever performed. It has been replaced by lateral straining cystograms and videourodynamics, from which subsequent classification systems distinguishing urethral mobility from intrinsic urethral dysfunction have developed. It certainly served an important purpose, identifying the relationship between urethral position, closure, and vaginal mobility (Mostwin et al, 1995).

Standard lateral upright and straining cystogram
          Jeffcoate and Roberts (1952) introduced lateral urethrocystogram and Hodgkinson (1953) introduced metallic bead chain urethrocystogram (Stamey, 1992). Bead-chain cystogram was never widely used in urology. Instead, standard upright static and straining cystograms were used, probably simplified (Bates et al, 1970) (Figures 1 &2).  
Figure 1 A normal, direct lateral urethrocystogram taking in the straining position from a continent female. The relationship of UVJ to symphysis pubis in young; normal; nonporous female was seen (Quoted from Stamey, 1992).       

Figure 2 Lateral cystourethrogram with straining in a patient with stress urinary incontinence. BN position was seen in relation to SCIPP line (Quoted from Stamey, 1992).
After a plain abdominal film is taken, the contrast material is instilled into the bladder via a 14-Fr urethral catheter. Contrast is infused until the patient complains of fullness. The catheter is removed and in a lateral position, the patient is asked to rest, strain, and void. This test may objectively show SUI, the BN funnels and opens on stress. In patient with ISD, the BN is fixed and always open (Raz et al, 1992). Greatest interest was not so much on identification of urethral and vaginal movement, per se, but on identification of urethral incompetence, which now designates ISD.  Standard upright lateral cystograms were used to identify urethral-funneling, vesicalization of urethra, or an incompetent BN as additional signs indicating urethral dysfunction (Mostwin et al, 1995).

Parameters of urethrocystography
Urethrocystography showed in demonstrable incontinence the average posterior urethrovesical angle was 140 degrees, and in the absence of incontinence 120 degrees. It has been observed that the relation between the vertical displacement of the internal urinary meatus in rest and stress was more than 5mm in women with incontinence. In women without incontinence it was less than 5mm. There was no difference in the range of the urethral length in women either with or without SUI (Tuskan et al, 1976). Normally, the BN is above the inferior ramus of the pubis symphysis and with stress maneuvers, should not descent more than 1cm. When urethrotrigonal angle is greater than 90ยบ it signifies funneling of BN (Raz et al, 1992).

Bladder neck dilation was seen in cystourethroscopy and lateral urethrocystography in SU incontinent women (Behr and Winkler, 1990). Urethrocystography showed that definite differences between continent and stress-incontinent patients as regards the pubo-urethral angle, but not as regards the posterior vesico-urethral angle (Voigt and Starker, 1985).

The best imaging method for the evaluation of female SUI is urethrocystography employing a single lateral view taken during coughing, with measurement of the BN descent angle. The other angles measured (PUVA, inclination angle, urethropelvic angle) while radiographs obtained at rest or during straining were not useful in the evaluation of female SUI (Varpula et al, 1989). Great importance has been ascribed to changes in the posterior vesicourethral angle (Grischke et al, 1990), the angle of inclination of the urethral axis, the flatness of the bladder base and its relation to pelvic outlet (Noll and Hutch, 1969).

No differences were seen in the incidence of radiographic findings in women with pelvic relaxation with or without SUI. All five cystographic criteria (posterior and anterior urethral angle, funneling of the proximal urethra on straining, the position of the urethrovesical junction and flattening of the bladder base) were similar in the continent and SU incontinent patients (Bergman et al, 1988 II)

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