Cardiff and Vale University Health Board say it has had to cancel more than 200 MRI scans since 2014 due to patients being obese.

The health board has now brought in a mobile scanner to try and tackle the problem.

Health chiefs have warned that obese patients could be putting their own lives at risk if they can’t get scans to spot life-threatening illnesses.

MRI scanners are used to detect a number of internal illnesses, injuries or conditions and are a vital tool for doctors wanting to diagnose ailments.

Standard sized scanners have a tunnel measuring 68inches in diameter and it’s understood most hospitals put a 25stone limit on patients entering them.

But Britain’s growing waistlines is piling on pressure on radiographers.

A spokeswoman for the Cardiff and Vale health board said: “We do our very best to ensure that all Radiology patients have equity of service.

“Patients who require a conventional MRI scan should fall within certain parameters, the scanner table holds a maximum weight of 25 stone and the bore of a conventional MRI scanner is 68 inches.

“We have recently implemented mobile MRI lorries which have a wider bore than conventional scanners.

“This process does not prevent patients outside of these parameters from receiving an MRI scan as those who are not suitable for a conventional MRI scan are referred for an open MRI scan instead.”

Sioned Quirke, of the British Dietetics Association, said: “The statistics are quite clearly showing increasing rates of obesity but services and equipment doesn’t seem to be growing in line with that.

“You’re now in the minority if you’re a healthy or normal rate and our waistlines are catching up with America.”

Richard Evans, chief executive officer of the Society of Radiographers said: “There are a lot of reasons not to become overweight and one might be that you need a scan that you cannot have.

“There are a number of other reasons not to get overweight in the first place, such as the increased risk of heart disease.

“It causes inconvenience to waiting lists - particularly if it’s not clear the patient will not fit in the machine until the day of the appointment itself.

“Then there is the additional problems that come with rearranged appointments such as the added costs to the NHS.

to the NHS when services are already under such pressure.”