Expediting emergent MRI in acute ischemic stroke by extending CT scout image: a simple intervention to decrease time to treatment
Yasmin Aghajan1, Rajiv Gupta2, Cristy Savage3, Frederick McNulty3, Michael Lev2, Aneesh Singhal4
1Neurocritical Care, 2Neuroradiology, 3Radiology, 4Neurology, Stroke, Massachusetts General Hospital
Objective:
We revised our acute stroke CT protocol to reduce time to MRI in acute ischemic stroke.
Background:
“Time is brain” in acute stroke. Patients requiring emergent MR imaging in the emergency department prior to thrombolytic treatment (e.g. wake-up strokes, iodinated contrast allergy, assessment of DWI/FLAIR mismatch) must undergo the MRI safety screen for implantable devices and foreign metallic bodies. Patient factors including neurologic deficits, language barrier, or lack of information on implantable devices make the screening process time-consuming. If patients cannot complete the safety checklist, radiographic clearance with chest and abdomen x-rays is pursued which delays time to treatment.
Design/Methods:
We revised our CT acute stroke radiology protocol to include scout images from the head to the femur to screen for foreign bodies, implantable devices or metallic objects. Standard CTA head and neck scout images previously only extended to the mid-chest. The new protocol obviates need for MRI screening checklist in emergent situations and allows to proceed directly from CT to MRI with the assistance of the radiologist interpreting the scout image.
Results:
Our multidisciplinary stroke team has implemented this change in our emergency department CT acute stroke protocol. The difference in additional radiation exposure is minimal to non-significant; the estimated total radiation dose of the topogram for the head, neck, chest, abdomen, and pelvic regions is approximately 0.24mSv (of which only the abdomen and pelvis are additional in this protocol). In comparison, the radiation dose of a standard abdomen/pelvis radiograph is 0.7mSv. Data collection is ongoing to measure impact on door to needle time.
Conclusions:
Revision of the CT stroke protocol to extend the CT scout from the head to the femur can expedite clearance for emergent MRI in patients who are candidates for thrombolysis or thrombectomy at no significant expense or radiation. This has potential to reduce time to acute stroke treatment.