An official report shows many hospitals are still not meeting important care standards for stroke patients - more than 15 years after the Scottish Government made the condition a priority.
Just 34 per cent of stroke patients for whom clot-busting drugs are appropriate receive them within an hour of reaching hospital, even though evidence shows they reduce the number of brain cells damaged.
A checklist of four other key treatment goals, including being admitted to a stroke unit and receiving a brain scan within a day of reaching hospital, was ticked for only 58 per cent of patients last year.
NHS Greater Glasgow and Clyde, the country's biggest health board, had one of the worst records in the country for meeting all four criteria. NHS Orkney was the only area to have a smaller proportion of patients treated in line with the four "care bundle" standards, and it did not have an operational CT scanner on the island.
Stroke is the third most common cause of death in Scotland and 10,233 people were diagnosed with a stroke in hospitals last year.
The care of patients has improved - the proportion treated in line with all four requirements of the care bundle was 48 per cent in 2012, a rise of 10 percentage points in a year.
Andrea Cail, Scotland director of the Stroke Association, said lives had been saved by the quality drive, but added: "There are still significant variations in treatment and care depending on where we live, which is unacceptable."
The Scottish Stroke Care Audit, which was published yesterday, revealed that in 2013, 12 out of 31 hospitals managed to admit 90 per cent of stroke patients to a stroke unit within a day and 13 ensured 90 per cent of patients were scanned within 24 hours. Both measures are known to improve the chances of survival and reduce the risk of disability.
Professor Martin Dennis, stroke specialist for NHS Lothian and chairman of the audit steering group, said it could be difficult to ensure patients were looked after in the right place when hospitals were very busy.
He said: "When a hospital is under pressure often they will use any medical bed that is available. That might mean that they are using a stroke unit bed for other sorts of patients. Then when the stroke patient comes in they have to try and sort that out, and that takes time."
Organising a scan in time, he said, could also be affected by the time a patient arrives in hospital, as not all centres have the staff required around the clock.
Once stroke patients have received a brain scan to rule out bleeding in the brain, patients should receive aspirin as soon as possible. The report notes the Royal Alexandra Hospital in Paisley gave 62 per cent of their patients the drug within a day last year, an improvement on the year before, but "still much lower than any other hospital in Scotland". The report said the low figure was "in part attributable to their delays in scanning patients".
Certain patients can also benefit from receiving a clot-busting drug within a short time after suffering their stroke - hence the target to inject them within an hour of reaching hospital.
Professor Dennis warned this was a difficult goal, saying it relied on ambulance crews to alert hospitals to the pending arrival of stroke victims and accident and emergency departments to diagnose strokes very swiftly.
The Stroke Association said there were many examples of good practice it would like to see replicated in other hospitals across Scotland.
But Ms Cail added: "Given the pressure on NHS funding in the years ahead, it will be very challenging to those who are striving hard to meet an optimum package of care. Innovative ways need to be found not just to meet and sustain the bundle, but also improve treatment and care across the stroke pathway."
A Scottish Government spokeswoman said there had been a 5.8 per cent drop in the number of deaths from strokes in Scotland since 2012, but there was still more to be done. An action plan is in place focusing on improving both emergency hospital care and support in the community during recovery.
NHS Greater Glasgow and Clyde said in a statement that it recognised that improving stroke services was a key goal. The board said: "We have already implemented significant improvements in all areas of stroke care.
"In 2013 we made major changes to the stroke service at the Royal Alexandra Hospital (RAH) which included the appointment of a new stroke consultant and a new stroke lead clinician identified, closer liaison with emergency and acute medicine to ensure quicker admission to the stroke unit, and regular meetings with staff to ensure consistency of data collection.
"This work has resulted in significant improvements in the numbers of patients having a swallowing assessment on the day of admission, speed of access to the stroke unit after admission and speed of prescription of aspirin.
"The installation of an additional CT scanner at the RAH has also seen 100% of patients receiving a scan within 24 hours of admission
"Similar changes are being implemented across Glasgow and the opening of the new South Glasgow Hospitals in 2015 will see further service improvements."