Fig. 6

A 19-year-old woman with mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes (MELAS) presenting with left homonymous hemianopsia. Hyperintensity on DWI (a) and FLAIR (c) with subtle restriction on ADC (b, arrowheads). Time-of-flight (TOF) images show regional arterial vasodilatation (d, arrows). Magnetic resonance spectroscopy shows significantly elevated lactate peak at 1.3 ppm (dotted arrow) and decreased NAA peak in the normal-appearing brain. A new lesion appeared 3 months later (f, g); the patient presented with right homonymous hemianopsia