WASHINGTON, DC - With the ability to detect intrinsic defects of the urethra and visualize the structure of the pelvic floor, supine HASTE MRI offers a less intrusive way to preoperatively assess stress urinary incontinence.
South Korean researchers discussed their findings at the American Roentgen Ray Society meeting today. They compared half-Fourier single-shot turbo spin echo MR (HASTE) to traditional voiding cystourethrography (VCUG), which requires that the bladder be filled with contrast media and emptied during imaging with the patient in an upright position.
"Stress urinary incontinence is a common disorder in women," said presenter Dr. Seung Eun Jung. "Despite the prevalence of this disorder, the anatomic reasons for urinary stress incontinence remain elusive."
Jung described tests done on 25 women with suspected urinary incontinence at St. Mary's Hospital in Seoul. MRI was performed with a 1.5-tesla unit and with the patients in a supine position. The study was done in 10 minutes, and three sets of data were obtained: axial and sagittal pelvic images of 6-mm section thickness and resting-straining midline sagittal images in single 10-mm section thickness.
The images were evaluated for mobility of the urethra and bladder neck, the posterior urethrovesical angle (PUV) and the anatomical change of levator ani muscle, and compared with the results of the standard bladder x-rays.
According to the results, HASTE MRI successfully visualized bladder neck and PUV descent in 80% (21 out of 25) patients, and these findings correlated with the VCUG evaluations. Degeneration or disruption of the levator ani muscle was seen in 68% (17 out of 25) patients with MRI.
Discrepancies were seen in five patients. In the majority of these cases, the MR findings were negative, but VCUG showed a drop in the bladder neck of greater than 2 cm and a PUV angle of greater than 180 degrees, Jung said.
Thecombination of the non-invasive technique, combined with the ability to image the patient in a supine position, makes HASTE MR a suitable replacement for the uncomfortable VCUG process, Jung concluded.
Previous studies have shown that MRI is able to show changes in the pelvic floor whether the subjects are in supine or sitting positions. A study out of Brigham and Women's Hospital in Boston found that while the sitting position does have a slight advantage, pelvic floor laxity and descent of the bladder neck were clearly seen from the supine angle (Am J Roentgenol, Dec. 1998, Vol.171:6, pp.1607-1610).
Earlier studies also have touted MRI for stress urinary incontinence. Researchers at the Brady Urological Institute in Baltimore stated that MRI is especially useful in diagnosing complex cases because the entire pelvic area can be studied. (Urol Clin North Am, Aug. 1995, Vol.22:3, pp.539-549).
But some clinicians still recommend VCUG as the best way to exclude bladder pathology, partcularly in younger patients who are at risk for future hypertensive and renal disease (Curr Opin Nephrol Hypertens Nov.1994,Vol.3:6, pp.660-664).
By Shalmali Pal
AuntMinnie.com staff writer
May 8, 2000
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