Around-the-Clock Brain Imaging Highland Hospital has 24-hour-a-day, 7-days-a-week radiology services available for brain imaging, including computerized tomography (CT) and CTA (CT angiogram). Brain imaging services that are available during the day include magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). According to the 2007 American Stroke Association's "Guidelines for the Early Management of Patients With Ischemic Stroke," a limited number of diagnostic tests are recommended for stroke evaluation, because excessive testing can delay necessary treatment. Tests used to diagnose a stroke, and the appropriate personnel to interpret the tests, should be available 24 hours per day, 7 days a week (Stroke, May 2007: 38(5); 1655-1711). Brain imaging using computerized tomography (CT), magnetic resonance imaging (MRI) or other valid method, is useful in screening for stroke and in ruling out brain hemorrhage (bleeding), but may not always be necessary prior to treatment.