Patients with emergency conditions (Priority 1) are seen immediately and are not included in wait times data. Priority levels 2, 3, and 4 are determined by surgeons, specialists, and other health care providers, based on clinical evidence, to guide treatment decisions and improve patient access and outcomes.
Wait times for diagnostic imaging in Ontario are measured from when a facility with the diagnostic imaging service receives the request from the patients’ doctor to book a Computerized Tomography (CT) or Magnetic Resonance Imaging (MRI) scan, to the patients having the scan.
Metrics reported for the wait times for diagnostic imaging (CT and MRI scans), for priority levels 2, 3 and 4, and those three priority levels combined:
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The average number of days patients waited for the scan; a lower number is better.
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The median number of days patients waited for the scan (half of the patients waited fewer than this number of days and the other half waited longer). A lower number is better.
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The 90th percentile number of days patients waited for the scan (90% of patients waited this number of days or fewer, while 10% waited longer). A lower number is better.
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The percentage of patients scanned within the target time for the 90th percentile (the target time within which 90% of patients were scanned). A higher percentage is better.
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The volume, or number of patients scanned during the month reported.
| Priority level of patients’ condition | Clinical description | Target time* from CT or MRI order received, to having the scan |
| Priority 1 | Any condition in which failure to diagnose and initiate treatment would result in serious morbidity/mortality | Patients have the scan within 24 hours of order received (not included in wait times data reported) |
| Priority 2 | Any condition in which failure to diagnose/treat would result in significant deterioration/deficit | Patients have the scan within 48 hours of order received |
| Priority 3 | Any condition in which failure to diagnose/treat would result in moderate deterioration/deficit | Patients have the scan within 10 days of order received |
| Priority 4 | Any condition in which failure to diagnose/treat would result in minimal deterioration/deficit | Patients have the scan within 28 days of order received |
*The target time within which 90% of patients are scanned
Data source for diagnostic imaging wait times:
Wait Time Information System™ (WTIS™), Ontario Health