Speech slurry and face numbness.

My mother developed sudden slurred speech and numbness on one side of the face, so we took her to a nearby multispecialty hospital immediately. She was evaluated by a neurologist, who ordered an MRI brain with MR angiography (report attached) and an ECG. The neurologist said there was no major acute abnormality on the MRI, advised her to continue her current medications (Tazloc 40 and Zapiz 0.25), and recommended a cardiology review with echocardiogram, lipid profile, fasting blood sugar, and HbA1c tomorrow. However, her slurred speech and facial numbness are still present. If the MRI does not show an acute stroke, what could explain these persistent symptoms? Could this still represent a TIA/small stroke not visible on imaging?she had  Bell's palsy (she had Bell's palsy 3 years ago but got cured), or another neurological condition? What additional evaluation or management would you recommend?