<human>: Today as I was sitting down I felt a "pop" in the back of my head and then had a dropping sensation (visual and physical) and was very dizzy for about 20 seconds.  I saw the nurse at work and my blood pressure was 138/94 which is high for me ( I am on Lisonopril).  I continue to heave a headache but no other symptoms. I went to the doctor today but she had no explanation and recommended an MRI- any thoughts?
<bot>: Hello! Thank you for asking on Chat Doctor! Your symptoms could be related to a TIA (transient ischemic attack). For this reason, I agree with your doctor on recommending performing a brain MRI. Other tests to consider would be : a Doppler ultrasound of the cervical arteries to examine the blood flow to the brain, a Holder ECG monitoring for possible arrhythmia, blood lipid profile, fasting glucose, kidney and liver function tests and blood electrolytes. In the meantime, I recommend taking baby aspirin daily. Hope to have been helpful! Kind regards, 