Doctors plan to gradually reduce Sharon's sedation and revive him in order to assess how much damage his brain sustained in a severe stroke he suffered on 4 January.
The process is expected to take several hours.
Doctors said a scan of Sharon's brain on 8 January showed improvement, with swelling down and skull pressure normal.
"A CT [computed tomography] scan was performed and we see a slight improvement in the edema of the brain," said Shlomo Mor-Yosef, the director of Jerusalem's Hadassah hospital where Sharon is being treated. "There is reduction in the size of the brain ventricle and the drainage of the cerebrospinal fluid is within normal limits. All these signs show slight improvement in the imaging of the prime minister's brain."
Doctors have said they may be able to save Sharon's life, but have warned he is unlikely to be able to return to his duties as prime minister.