MR urography in the diagnosis of urinary tract obstruction.

OBJECTIVE: To evaluate the efficiency of MR urography in depicting the urinary tract. METHODS: 33 patients with urinary tract abnormalities were additionally evaluated with MR urography. 25 had dilated upper urinary tracts because of urinary obstruction and 8 had normal tracts. MR urography was performed with a 1,5T magnet using a heavy T2w sequence (3D-IR-TSE) in the coronal plane. Images were post-processed using the MIP algorithm. Both reconstructed and source images were evaluated. The results of MR urography were compared with the final diagnosis, which was established surgically in 23 cases, and with multimodality imaging workup in 10 cases. RESULTS: MR urography correctly depicted the level of obstruction and the degree of dilatation of the urinary tract in all 25 patients with hydronephrotic kidneys (sensitivity 100%). Additionally, it succeeded in suggesting the underlying pathology in 25 cases (48%). Concerning the 8 patients without dilatation of the urinary tract, there was either no depiction or depiction was bad. CONCLUSION: MR urography, a new noninvasive technique, demonstrates 100% sensitivity in diagnosing urinary tract obstruction and also suggests the underlying pathology in many cases. In nondilated systems it is not possible to get good images because MR urography only depicts fluid in the urinary tract. Thus we believe that MR urography can provide a reliable alternative in selected cases as opposed to other more invasive modalities, such as retrograde or antegrade urography, and is without the risk of contrast media and radiation exposure.

Isolation of a cDNA clone from colon carcinoma.

cDNA clones of differentially expressed mRNAs in a colon carcinoma have been isolated by subtractive cDNA cloning. The substracted material was at least 90x enriched for differentially expressed sequences and can be used for the construction of substractive cDNA libraries and polymerase chain reaction (PCR) amplification to generate differential probes. In this way rare mRNA (less than 0.1% abundance) which are differentially expressed, can be isolated utilising this procedure. A cDNA clone which we call IH12 has been isolated. Its mRNA is expressed exclusively in actively proliferating cells.

Prevalence of spina bifida occulta in patients with functional disorders of the lower urinary tract and its relation to urodynamic and neurophysiological measurements.

OBJECTIVE: To determine the relation between neurophysiological abnormalities and the radiological detection of spina bifida occulta in patients with dysfunction of the lower urinary tract. DESIGN: Blind assessment and subsequent decoding of mixed batch of abdominal radiographs from patients with and without urological symptoms for evidence of spina bifida occulta and comparison of results with those of previous control series. SETTING: Review study among tertiary referrals to an incontinence clinic of a city hospital. PATIENTS: One hundred and thirty eight adults with proved urodynamic abnormalities in whom neurophysiological measurements were available. INTERVENTIONS: None. END POINT: Correlation of neurophysiological abnormalities in lower urinary tract dysfunction with presence and type of spina bifida occulta and level of opening of posterior sacral arcs. MEASUREMENTS AND MAIN RESULTS: On decoding radiographs those from patients without urological symptoms showed a similar prevalence of spina bifida occulta to that in the control series (631/2707 controls; 23%). By contrast, patients with urological symptoms had a significantly increased prevalence of spina bifida occulta at S1 and S2 and a higher level of opening of posterior sacral arcs. The increased prevalence of the bony defect was particularly striking in men with urgency and instability and in women with stress incontinence. No significant correlation was found between any particular neurophysiological abnormality and the presence of spina bifida. CONCLUSIONS: In patients with dysfunction of the lower urinary tract neurophysiological abnormalities may be associated with congenital dysraphic lesions in the lower lumbar spine and sacrum. There appears to be no direct causal relation between the radiological and neurophysiological abnormalities but the findings suggest a common aetiological factor.

Neurological defects of the voiding reflex arcs in chronic urinary retention and their relation to spina bifida occulta.

A group of 37 patients (24 female and 13 male) with chronic urinary retention and without demonstrable mechanical obstruction had neurophysiological measurements of their lower urinary tracts to detect any neurological abnormality which might relate to the disorder. These consisted of measurements of the electrosensitivity of the dorsal nerve of the penis/clitoris and of the urethra, measurement of the sacral reflex latencies (SRL) from dorsal nerve to urethra and to anus and between urethra and anus and EMG studies of the urethral and anal sphincters. The results suggest that female patients in particular have significant neurogenic defects in the voiding reflex arcs which find their clinical expression in detrusor underactivity with urinary retention. Plain X-rays of the renal tracts (KUB films) were also studied for the presence of spina bifida occulta. The prevalence of this defect was significantly higher than in normal controls, suggesting that in some of these patients the nerve defect might be related to a tethered cord in association with spina bifida occulta.

Neurophysiological abnormalities in genuine female stress urinary incontinence.

Perineal sensory and motor function was investigated in 28 women with genuine stress incontinence of urine and compared with a matched control group. Electrosensitivity of the dorsal nerve of the clitoris and of the urethral mucosa was significantly diminished in these patients (eight measurements 'insensitive'). Three different reflex latency measurements (dorsal nerve to external anal sphincter, dorsal nerve to urethral sphincter, urethral mucosa to external anal sphincter) were prolonged in incontinence (14 absent reflexes). Mean motor unit potential duration of the external anal sphincter was also prolonged, reflecting an early neuropathy. Anorectal manometry detected significantly weaker squeeze pressures in stress incontinence although other variables were unaffected.

Neurophysiological measurements in patients with genuine stress incontinence of urine and the relation of neurogenic defects to the presence of spina bifida occulta.

Neurophysiological measurements comprising surface electromyography (EMG) of the urethral and anal sphincters, measurement of the sensory thresholds of the dorsal nerve (DN) of the clitoris and the urethra and sacral reflex latencies from the dorsal nerve to urethra and anus and from the urethra to anus were performed in 44 females with genuine stress incontinence, in order to detect any relationship between the clinical disorder and a neurogenic defect in the innervation of the muscles involved in maintaining continence. Plain X-rays of the renal tracts (KUB films) were also studied to establish whether the prevalence of spina bifida occulta was increased in this group of patients and was a likely explanation for the nerve defects. Forty-three patients were found to have abnormal neurophysiological responses and the prevalence of spina bifida occulta was 50%, which compares with a prevalence of 17% in normal female controls. Genuine stress incontinence appears to be at least partly associated with defective innervation of the lower urinary tract and it is likely that in some cases the defect may be related to the presence of spina bifida occulta.

Neurophysiological measurement of the voiding reflex arcs in patients with functional disorders of the lower urinary tract.

Neurophysiological measurements were carried out in 180 patients presenting to a Joint Incontinence Clinic with a history of lower urinary tract dysfunction. A full urodynamic assessment was performed along with neurophysiological measurement of the voiding reflex arcs. The majority of patients were shown to have significantly abnormal responses on neurophysiological measurement when compared with normal controls. Two particular groups, patients with acute retention and females with stress incontinence, were shown to have markedly poorer results than patients with other urodynamic problems. These results suggest that many patients with lower urinary tract dysfunction may have a neurological component.

Ultrasound as an alternative to intravenous urography in prostatism.

Seventy-five patients, with uncomplicated benign prostatic hypertrophy referred for pre-prostatectomy assessment, were studied to determine whether renal tract ultrasound combined with plain films of kidney, ureters and bladder could provide an acceptable alternative to intravenous urography (IVU). All patients had both IVU and ultrasound. Bladder residual urine volumes were calculated by ultrasound measurements. Fifty-nine (78%) patients had normal IVU and ultrasound. Twelve (16%) had both abnormal IVU and abnormal ultrasound. Four (6%) had positive findings on one examination not detected on the other: two of these occurred with ultrasound and two with IVU. Measurement of residual volume of urine in the bladder by ultrasound and IVU is discussed. The combination of ultrasound and a plain radiograph of the urinary tract provides more information and should replace IVU in the preoperative assessment of patients with uncomplicated benign hypertrophy of the prostate.

Prevalence and patterns of spina bifida occulta in 2707 normal adults.

Plain radiographs of the urinary tract on 2707 normal volunteers were reviewed to establish the prevalence and patterns of spina bifida occulta in the normal population. Abnormalities in the formation of the posterior arch were identified in 23%, and four different patterns are described. In this group of subjects the condition was twice as common in males as in females (P less than 0.001) and commoner in younger adults. The commonest defects were either in S1 alone or involved S1 and S2 together. Isolated defects at L5 or S2 were rare. The level of opening of the posterior sacral arcs was assessed and a high level of opening was shown to correlate with the presence of spina bifida occulta.

Sacral reflex latency in acute retention in female patients.

Neurophysiological measurements of the innervation of the lower urinary tract were performed on 14 female patients presenting with unexplained acute urinary retention. The method consisted of (a) static electromyography (EMG) of the anal and urethral sphincter with the patient relaxed, coughing and gripping, (b) the study of sensory thresholds on the dorsal nerve of the clitoris and in the urethra, (c) the measurement of sacral reflex latencies (SRL) from the dorsal nerve of the clitoris to the anus and urethra and from the urethra to the anus. The results showed that all 14 patients had significant defects in the innervation of their lower urinary tract. These findings suggest that a neurological explanation for acute retention in women should always be sought before making any other diagnosis.

Neurophysiological measurements in primary adult enuretics.

The nerve supply of the lower urinary tract was studied in 25 primary adult enuretics by full urodynamic assessment and neurophysiological measurements. The latter consisted of the measurement of static EMG, sensory thresholds and sacral reflex latencies (SRL). All patients were normal on clinical neurological examination. All neurophysiological measurements were within normal limits in only three patients and the remaining 22 had at least one abnormal response. The commonest abnormality was a high or even absent urethral sensory threshold. These defects in sensory and motor innervation correlated with the clinical dysfunction. It was concluded that this is a valuable method for the detection of nerve defects in the lower urinary tract, especially when the clinical neurological examination is normal.