Doppler artifacts after vesicoureteral reflux treatment may be misdiagnosed as ureteral stones

Reuters Health - 09/07/2021 - The twinkling artifact in follow-up sonography of children after endoscopic vesicoureteral reflux (VUR) treatment can be misinterpreted as a ureteral stone, resulting in inappropriate treatment, researchers say.

Misdiagnosis is particularly likely if the child presents with abdominal complaints and a history is not available, Dr. Marc Steinborn of Munich Clinic Schwabing in Germany told Reuters Health by email.

The study was prompted, he said, by the group's own case "where the twinkling sign of a deflux deposit led to a wrong diagnosis."

He pointed to two "new" aspects of the current study compared with previous reports about misdiagnosis. "First, we found that calcification of the deposits can be found in about 25% of patients on sonographic follow-up studies," he noted.

"Second," he said, "the twinkling artifact, which is a sensitive tool for the detection of ureteral calculi on sonography, is a common finding in deflux deposits as well. This means that the risk of confusing a calcified deposit with a ureteral calculus can be increased when the twinkling sign is used."

As reported in the Journal of Pediatric Urology, Dr. Steinborn and colleagues assessed B-mode and color-coded Doppler sonography imaging in the follow-up of 40 children (mean age 9.5 years; 80% girls) after endoscopic treatment of VUR (62 treated units).

Follow-up sonography was performed after a mean post-procedure interval of 48.8 months.

Forty-seven of the injected units (75.8%) could be identified on follow-up. In 13 units (27.7%), posterior acoustic shadowing was noted. On color Doppler sonography, a twinkling artifact appeared in 26 (55.3%) of the visible cases.

There was a statistically significant correlation between a positive twinkling sign and the deposit age - i.e., the average age of the twinkling-positive deposits was 64 months, compared to 30.1 months in the twinkling-negative deposits.

Seven of the twinkling deposits (27%/11.3% of all deposits) were considered to have the potential to be misdiagnosed.

Dr. Steinborn said, "Clinicians, especially those doing ultrasound, should be aware of the typical imaging appearance of deflux deposits and always ask for the patient's history if they see a calcified twinkling-positive structure behind the bladder."

"This is especially important," he added, "as an increasing number of children are treated by endoscopic deflux injection and a growing number of treated patients will reach adulthood."

Dr. John Amodio, Chief, Pediatric Radiology at the Northwell-affiliated Cohen Children's Medical Center in Queens, New York, commented by email. "I think the findings are substantial. However, an issue with the methodology is that the observers were not blinded to each other's interpretation, so there may be some bias in the results of the study."

"While the authors draw the reader's attention to the potential pitfall of mistaking an implant from true calculus," he said, "there is not much discussion regarding how to distinguish the implant from true ureteral stones. This can be problematic when there are inadequate medical records and/or the patient's caregiver does not know what type of procedure was performed."

"There is a reference to a CT study which determined that if the area in question is less than 400 Hounsfield units, it is most likely implant calcification, rather than true ureteral stone," he noted. "I think more work is needed in this regard, as the presence of an implant does not necessarily negate the possibility of a superimposed ureteral stone."

SOURCE: https://bit.ly/2T0Ei4B Journal of Pediatric Urology, online June 17, 2021.

By Marilynn Larkin



Posted on 9 July 202119 July 2021