The parents of terminally-ill baby Charlie Gard have lost the latest fight in their legal battle over his treatment.
Chris Gard and Connie Yates and doctors at Great Ormond Street Hospital in London had been in disagreement over a brain scan carried out on the 11-month-old prior to a gathering of specialists.
The couple said an electroencephalogram (EEG) should be carried out for no longer than 30 minutes.
But specialists at Great Ormond Street, where Charlie is being cared for, said a scan would have to be carried out for at least four hours in order to generate useful data.
Mr Justice Francis has ruled in favour of Ormond Street doctors.
He said the scan should "be of such duration" as treating clinicians "may advise".
The judge did not analyse the dispute at a normal court hearing.
He had considered competing written arguments on Saturday, prior to experts gathering at Great Ormond Street on Monday and Tuesday.
But he has made detail of the out-of-hours dispute available to journalists.
Charlie's parents want Mr Justice Francis to rule that their son, who suffers from a rare genetic condition and has brain damage, should be allowed to undergo a therapy trial overseen by a specialist in New York.
Great Ormond Street specialists say the therapy is experimental and will not help.
They say life support treatment should stop.
Charlie's parents, who are in their 30s and come from Bedfont, west London, have already lost battles in the High Court, Court of Appeal and Supreme Court in London.
They have also failed to persuade European Court of Human Rights judges to intervene.
But the couple say there is new evidence and want Mr Justice Francis, who in April ruled in favour of Great Ormond Street and said Charlie should be allowed to die with dignity, to carry out a fresh analysis of their case.
In April, the judge ruled in favour of Great Ormond Street and said Charlie should be allowed to die with dignity.
Mr Justice Francis has considered the couple's latest claims at preliminary hearings in the Family Division of the High Court in London.
Last week, Mr Justice Francis suggested that the American specialist - Michio Hirano, a professor of neurology at the Columbia University Medical Centre in New York - should travel to London to meet Great Ormond Street doctors and other clinicians.
Dr Hirano has examined Charlie and discussed his case while visiting Great Ormond Street on Monday and Tuesday.
Mr Justice Francis is due to oversee further court hearings in the next few days.
The dispute about the scan arose at the weekend, prior to the expert gathering.
On Wednesday, Mr Justice Francis released the order he made after analysing emailed arguments from rival legal teams on Saturday.
The order gives an outline of the dispute and his decision.
Mr Justice Francis said Charlie's parents had agreed "in principle" to further "imaging" being carried out on the little boy's brain prior to the expert gathering.
He said the disagreement was over how long any scan should last.