Conjoined twins Nima and Dawa have undergone the first in a series of tests to determine when they will be fit for delicate separation surgery.
The 14-month-old girls from Bhutan, who are joined by the torso, spent Thursday having various tests and scans at Melbourne's Royal Children's Hospital to give doctors an idea of when the marathon operation can proceed.
"We need to just double check everything is alright generally," anaesthetist Ian McKenzie said.
"Once we get the results of all that, we'll be very keen to make a date and plan for surgery in the future. So far, so good."
The girls underwent a four-hour MRI scan with the results to be reviewed in the coming days, before medical experts finalise their treatment plan early next week.
Mr McKenzie said the sisters would have "quite a lot of tests", because doctors had scant information before their arrival in Melbourne on Tuesday.
Nutrition levels will be an important guide, with the girls' condition meaning they cannot be weighed separately.
"They're pretty skinny, they haven't been able to practise crawling the way normal kids would, so maybe their muscles haven't developed so well but we want to just double check everything is alright, generally," Mr McKenzie said.
"There's a whole lot of things they might have got in Bhutan they wouldn't get in Australia, and we need to just have our guard up that we haven't got a surprise illness we hadn't thought of, that might be very common there."
The planned separation at the Royal Children's Hospital includes splitting the girls' shared liver.
The hospital's head paediatric surgeon Joe Crameri is reassured the twins are active and interacting with one another and that mum has been feeding the girls well.
"They look like happy healthy girls who are reacting quite well with one another," he said.
"So far, everything is going along the pathway that we've been hoping for."
Dr Crameri said image scans will be key to determining if it's the right time for the girls to separate.
The surgery and recovery are estimated to cost at least $350,000.
The state government pledged to cover the surgery, with other funds raised to go towards the girls' stay, rehabilitation and future.
Australian Associated Press
