Dr Teh Hui Seong, Consultant Radiologist, presented his study on 1 May 06 during the American Roentgen Ray Society (ARRS) Annual Meeting in Vancouver, British Columbia on using MRI to diagnose ureteral reflux. The ARRS was founded in 1900 and is the oldest radiology society in United States. It was named after Wilhelm Roentgen, who discovered the x-ray in 1895.

Together with researchers at the University of California-San Francisco, Dr Teh’s study showed that MRI provides excellent detail of the anatomy of the urinary system and can be used as a potential screening examination for vesicoureteral reflux, or VUR. His study created waves of interest in the radiological field and was reported in the international press such as United Press International (UPI) and The Washington Times.

In a healthy person, urine is excreted by the kidneys and flows down the ureter into the bladder. In patients with VUR, there is an abnormal reverse passage of urine from the bladder back up into the kidney. This may cause urinary tract infections and kidney damage, especially in young children.

"The incidence of VUR is under 1% in healthy children, but is 20-50% in children with urinary tract infections," said Dr Teh, lead author of the study.

The current radiological tests for assessing VUR involve significant radiation to the patients. Patients with this condition often require repeated examinations to monitor disease progression and assess treatment effectiveness.

Dr Teh started his research at CGH in 2004. For the study, five adult patients at CGH who had VUR detected by conventional X-ray underwent MRI. For both X-ray and MRI, contrast material was put into the bladder using a small tube and the ureters are imaged repeatedly using X-rays or MRI, respectively, to look for reverse flow of contrast into the ureters. For MRI, doctors usually obtain a static image of the urinary system but Dr Teh used a dynamic MRI technique to detect the passage of urine from the bladder to the kidneys in real time.

The researchers found that the two methods were similar in diagnosis for 80% of the ureters in these patients. The other 20% was split, with MRI detecting VUR in one ureter and X-ray detecting it in the other. The researchers also found that MRI method was better than X-ray as it could show scarring of the kidneys and loss of kidney tissue, which is related to the extent of kidney damage from VUR.

"Minimising radiation exposure to the patient is a great concern,
particularly for children. For a child 5 to ten years of age,
it has been estimated that the radiation exposure
from a single conventional X-ray cystography
is equivalent to that of 20 chest
X-rays or six months of natural background
radiation," said Dr Teh. "MR cystography is
accurate and more importantly,
doesn't expose patients to ionising radiation,” he added."

Crediting the success of his study to the invaluable support of his colleagues, Dr Teh said, “I am grateful to CTRU (Clinical Trials and Research Unit) at CGH who helped with the research grant application and the urologists for referring their patients to participate in my study,” said Dr Teh.