Jack had a blocked heart valve
A British six-year-old boy has become the first person in the world to have a heart valve widened using an MRI scan for guidance rather than X-ray imaging.
Jack Walborn was born with the heart condition pulmonary valve stenosis, which reduces blood flow to the lungs.
Using MRI means patients are not exposed to radiation - particularly important for children.
The scan also provides a clearer image, and information about the body's tissues, in real time during surgery.
Jack's condition meant that the flow of blood from the right side of his heart was obstructed.
Surgeons decided he needed an operation called a valvuloplasty to widen the valve and increase blood flow.
This is done by inserting a catheter into a blood vessel in the arm or groin and guiding it to the heart.
At the tip of the catheter is a balloon which is gently inflated to widen the narrowed valve.
Glass fibre wire
X-ray imaging is usually used to track the progress of the catheter through the body.
But a team at the King's Health Partners Academic Health Sciences Centre in London has developed a way to use MRI scanning instead.
Previously, the magnetic field used in MRI caused problems with the metal guide wires used for cardiac catheterisation, making them move around inside the body and heating them up.
The King's team have come up with a glass fibre wire alternative with small iron markers along it that can be seen on the scan.
His mother Kerry said: "At first I was unsure about allowing Jack to be the first person to have this operation, but once I had spoken to the doctors I felt much more at ease as I knew he was in safe hands.
"His surgery was a great success and within an hour of coming out of theatre he was running around and back to being his lively self."
Judy O'Sullivan, a senior cardiac nurse at the British Heart Foundation, said: "Technology is advancing at a great pace and in the future we hope that many more patients will benefit from the use of MRI scans rather than X-ray imaging, as MRI avoids exposure to radiation."