Studies of patients presenting with AVS related to infarct have shown an overall sensitivity of approximately 80% for MRI performed within 24 hours of symptom onset. Early MRI, however, may be negative in half of cases when the area of infarct is small (<10 mm in size) and located in the brainstem/cerebellum. Patients with these small areas of infarct are also those more likely to present with isolated AVS. In these cases, delaying MRI until at least 48 hours from symptom onset or repeating an initially negative MRI will improve lesion detection [29]. Variant 3: Adult. Acute persistent vertigo. Abnormal neurologic examination or HINTS examination is consistent with central vertigo. Initial imaging. Posterior circulation strokes involving the brainstem and cerebellum account for a smaller proportion of acute stroke presentations but may have severe devastating and debilitating consequences. It is estimated that 25% of AVS are caused by stroke. Approximately 20% of these patients have focal neurologic signs whereas the remainder have Dizziness and Ataxia CT Head With IV Contrast There is no relevant literature regarding the use of postcontrast head CT in the evaluation of suspected acute posterior fossa stroke. CT Head Without and With IV Contrast There is no relevant literature regarding the use of postcontrast head CT in the evaluation of suspected acute posterior fossa stroke. CT Head Without IV Contrast CT is usually performed first in the emergency setting for workup of acute stroke. Hemorrhage can be excluded rapidly to select patients for thrombolysis. Posterior fossa ischemic strokes are difficult to detect on CT with a low sensitivity (~10% at a single academic emergency department in 610 patients in a 2-year period) [6].
Dizziness and Ataxia. Studies of patients presenting with AVS related to infarct have shown an overall sensitivity of approximately 80% for MRI performed within 24 hours of symptom onset. Early MRI, however, may be negative in half of cases when the area of infarct is small (<10 mm in size) and located in the brainstem/cerebellum. Patients with these small areas of infarct are also those more likely to present with isolated AVS. In these cases, delaying MRI until at least 48 hours from symptom onset or repeating an initially negative MRI will improve lesion detection [29]. Variant 3: Adult. Acute persistent vertigo. Abnormal neurologic examination or HINTS examination is consistent with central vertigo. Initial imaging. Posterior circulation strokes involving the brainstem and cerebellum account for a smaller proportion of acute stroke presentations but may have severe devastating and debilitating consequences. It is estimated that 25% of AVS are caused by stroke. Approximately 20% of these patients have focal neurologic signs whereas the remainder have Dizziness and Ataxia CT Head With IV Contrast There is no relevant literature regarding the use of postcontrast head CT in the evaluation of suspected acute posterior fossa stroke. CT Head Without and With IV Contrast There is no relevant literature regarding the use of postcontrast head CT in the evaluation of suspected acute posterior fossa stroke. CT Head Without IV Contrast CT is usually performed first in the emergency setting for workup of acute stroke. Hemorrhage can be excluded rapidly to select patients for thrombolysis. Posterior fossa ischemic strokes are difficult to detect on CT with a low sensitivity (~10% at a single academic emergency department in 610 patients in a 2-year period) [6].