Prime Minister Ariel Sharon's brain scan Thursday evening showed positive results, indicating that the remnants of the blood in his brain from a massive stroke last week have been absorbed, hospital officials said in a statement.

In response, doctors had removed a tube they had inserted into Sharon's skull to relieve pressure on his brain, the statement from Hadassah Hospital said.

"The Prime Minister's heart rate is regular and body temperature is normal," said a statement from Hadassah hospital, where Sharon is in what doctors described as critical but stable condition after suffering a massive stroke last week.

The hospital added that doctors placed a permanent intravenous drip in his arm. It described the surgical procedure as a success.

It said Sharon was being taken back to the neurological intensive care unit after the completion of the procedure.

A member of Sharon's medical team said that the information about the brain disease diagnosed after his first stroke on December 18 had been concealed out of "political reasons," Channel 10 television reported Wednesday.

The controversy surrounding Sharon's medical treatment has continued unabated, with his doctors coming under further criticism for concealing the diagnosis of cerebral amyloid angiopathy (CAA).

Senior executives at Hadassah University Hospital, Ein Karem, where Sharon was first treated in December and again since last Wednesday when he had the second, far more severe stroke, admitted this week that the hospital's doctors had decided to give the pime minister blood thinners despite the diagnosis of CAA.

The physicians had promised "full disclosure of [Sharon's] condition in the wake of his hospitalization" in December.

The doctor said there was the fear that if made public, the information would be used against Sharon and his Kadima party, particularly in light of the fact that CAA has often been associated in medical literature with Alzheimer's Disease.

Sharon was in critical but stable condition Thursday morning, a statement from Hadassah said.

"The prime minister's condition remains critical but stable," said the statement. "His heart rhythm is regular. In the evening he will undergo a routine CT scan."

Surgeons tending to Sharon were expected to decide on when to stop the intravenous drip completely at a daily consultation scheduled for 7 A.M., medical sources said Thursday.

"The prime minister's treatment is constantly being reviewed, but the decision to end sedation outright requires a major deliberation," said a source.

As published in Haaretz previously, senior physicians say anticoagulants such as the Clexane given to Sharon significantly increase the risk of stroke in people with CAA.

Sharon's physicians, Prof. Boleslav Goldman and Dr. Shlomo Segev, as well as Hadassah officials, did not comment Wednesday.

The condition of Sharon, who has been hospitalized since last Wednesday night with his second stroke in less than a month, did not change significantly Wednesday. Sharon is still in serious but stable condition and his life is still in danger.

Doctors at Hadassah University Hospital were lowering Prime Minister Ariel Sharon's sedation to a "minimal" level Wednesday night, in a further effort to awaken him gradually from the coma in which he has lain since his massive stroke and brain hemorrhage seven days ago.

The hospital has been gradually reducing Sharon's sedation since Monday.

According to officials from Hadassah University Hospital, Ein Karem, "An additional slight improvement" in his condition was recorded. A hospital official told Haaretz on Wednesday that once again, Sharon's movements in response to pain stimuli were "greater." Also, Sharon's blood pressure was found to rise when his son spoke to him, one of his attending physicians, Dr. Felix Umanski, said late on Wednesday.

Dr. Yair Birenbaum, a senior Hadassah official, told Razi Barkai of Army Radio Wednesday that the decision by Hadassah physicians to give Sharon anticlotting drugs despite the vascular disease was not, "in my humble opinion, an error in judgment. The consultation about the prime minister was attended by a range of doctors with various specialties," and that Sharon's vascular disease was "one more variable that had to be calculated within a range of variables."

Dr. Birenbaum also noted that the physicians at Hadassah considered the variety of blood-thinning drugs available and "considered various options and decided what was decided by a general consensus of the caregivers."

In response to the call, which appeared in Haaretz Wednesday, by a doctor who is a department head at a major Israeli hospital, for a state commission of inquiry into Sharon's treatment, Birenbaum said there is no need for that. However, he added that "there is plenty of time for examination committees and snoopers" and promised that if an investigative body is established "everything will be laid out" before it.

A senior neurologist at a government hospital in the center of the country told Haaretz Wednesday that "it is known the treatments in modern medicine are always involved in an attempt to find a balance between risks and rewards, but in this case it is really impossible to understand the doctors' decision regarding the use of blood thinners.

"According to the medical literature, after the first stroke it seems as if the need to use anticoagulants was not very great, after the small hole in the heart was discovered. Therefore, the question becomes even more pressing."