Novel multimodality imaging for the evaluation of obstructed urinary system in kidney stone disease patients.

Plain English summary of protocol

Background and study aims
Abdominal pain is a common reason people end up in the emergency room, and about 5% of these cases are due to kidney stone disease (KSD). This condition affects 13% of men and 7% of women, and if not treated properly, it can come back in 50% of cases within 5 years. In the United States, dealing with KSD costs around $5 billion each year, covering hospital stays, procedures to remove stones, and lost work hours.

Experts from the American Urological Association (AUA) and the American College of Radiology (ACR) recommend using CT scans as the first imaging test for these patients. However, while CT scans can identify the presence of kidney stones and certain signs of blockage, they don't directly show whether there's an obstruction, how well the kidneys are working, or the flow dynamics of urine. Instead, they rely on secondary signs like "fat stranding" or a dilated collection system to determine if there's a blockage, but these signs aren't very reliable, with only a 56% accuracy.

It's crucial to rule out obstruction quickly because kidney function can recover if treated promptly. If left untreated for weeks, though, obstruction can cause irreversible damage and potentially lead to chronic kidney failure. Outflow obstruction from the kidney can also cause other issues like chronic tubulointerstitial disease, bladder residual urine, chronic or recurring urinary tract infections, incontinence, and problems from long-term catheter use.

There's a common belief that stones smaller than 5 mm will pass through the urinary system on their own, but recent studies dispute this idea. Stones as small as 4 mm may not naturally be expelled. MAG3 scintigraphy, a test using 99mTc-MAG3, has been found to detect some degree of obstruction in up to 50% of cases with silent ureteral stones (stones without symptoms). This method, done with conventional gamma camera/scintigraphy, has a high positive predictive value (PPV) of 90.6% for diagnosing obstructive kidney disease.

Advanced equipment, like Digital SPECT/CT, can perform both a CT scan and a 99mTc-MAG3 digital scintigraphy simultaneously. Our research group, with previous experience in diagnostic imaging and kidney stones, aims to build on this by using state-of-the-art equipment to further our understanding of these conditions.

Who can participate?
Adult patients with a confirmed kidney stone disease at CT.

What does the study involve?
We will perform a SPECT/CT study in a novel CZT camera as part of routine care.

What are the possible benefits and risks of participation?
The expected benefit is the detection and better characterization of obstruction secondary to kidney stone disease. The risk is would be increased pain during the study due to the use of a diuretical agent.

Where is the study run from?
Clinical Physiology Department, Nuclear Medicine Unit, Linköping University Hospital (Sweden)

When is the study starting and how long is it expected to run for?
February 2019 to March 2024

Who is funding the study?
Linköping University Hospital, Clinical Physiology Department (Sweden).

Who is the main contact?
Miguel Ochoa Figueroa, MD, PhD, miguel.ochoa.figueroa@regionostergotland.se

Contact information

Dr Miguel Ochoa Figueroa
Public, Scientific, Principal Investigator

Fysiologiska Kliniken
Universitetssjukhuset
Linköping
58963
Sweden

ORCID ID	0000-0001-9444-8225
Phone	+46 101039090
Email	miguel.ochoa.figueroa@regionostergotland.se

Study information

Eligibility

Locations

Countries of recruitment

• Sweden

Study participating centre

Sponsor information

Funders

Funder type

Hospital/treatment centre

Results and Publications

Study outputs

Additional files

44635 PIS (Swedish).pdf

Editorial Notes

02/09/2024: Publication reference added.
08/03/2024: Total final enrolment added.
24/11/2023: Trial's existence confirmed by Etiksprövningsmyndigheten.