But he said that and the other injuries caused in the vehicle collision would not have been enough to kill the victim.
"She could have lived for days and possibly even survived, possibly without medical treatment. It wouldn't have been comfortable but it's possible," Dr Wigren said.
Nearly a dozen "sharp-force" wounds were much more serious, in the witness' opinion.
"Her throat had been slashed ... she was essentially drowning in her own blood," he said.
A severe stab wound near Mrs Gotingco's neck was inflicted with such force the Seattle-based pathologist found links from her necklace embedded in its depths.
And one of the most significant - 14.5cm long and 2cm deep - partially cut through her windpipe and exposed her jawbone.
When Mrs Gotingco's lungs were dissected, Dr Wigren found a "mottled, reddish colour".
"What this tells me is blood has been inhaled into the deepest parts of the lung ... she was alive and she was breathing [when the wound was inflicted]," he said.
There were more subtle injuries to the cartilage inside Mrs Gotingco's throat, combined with burst capillaries in her eyes, which led the expert to the conclusion she had been strangled during the attack, possibly to stop her resisting.
Chris Wilkinson-Smith - who is acting as amicus curiae (friend of the court) after being sacked by the defendant - said another pathologist, Dr Robert Chapman, would be called to give evidence for the defence.
The lawyer said Dr Chapman disagreed with the strangulation theory and did not believe there was enough blood found in the lungs to determine Mrs Gotingco inhaled it.
"He's wrong," said Dr Wigren. "I think his review of the photographs and the last page of my report was cursory at best."
The trial, before Justice Timothy Brewer and a jury of seven women and five men, is scheduled to last a further two weeks.
NZME.