Figure 2.
A 52-year-old woman with transient ischemic attacks of right hemiparesis and motor aphasia due to moyamoya disease. (a) Preoperative 15O gas positron emission tomography images show a decrease in cerebral blood flow (CBF) and an increase in cerebral blood volume (CBV) in the left precentral and central regions where cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction fraction (OEF) are slightly decreased and markedly increased, respectively. (b) Preoperative Technetium-99 m-labeled (99mTc) ethyl cysteinate dimer (ECD) single-photon emission computed tomography (SPECT) images at rest (left) show a decrease in tracer uptake in the left precentral and central regions relative to that in the left cerebellar region. This difference in tracer uptake is decreased on 99mTc-ECD SPECT images with hyperventilation challenge (right). The left-to-right precentral and central differences in tracer uptake are also decreased on 99mTc-ECD SPECT images with hyperventilation challenge when compared with those at rest. (c) N-isopropyl-p-[123I]-iodoamphetamine (IMP) SPECT images one day after arterial bypass surgery reveal a focal increase in CBF in the left precentral region perfused by an anastomosed M4 of the left middle cerebral artery (left). Aphasia developed three days after surgery and propofol coma continued for five days. Right hemiparesis developed after recovery from this coma. This hemiparesis remained at one month after surgery when 123I-IMP SPECT images demonstrate resolution of a focal increase in CBF in the left precentral region and development of a focal decrease in CBF in the left central region (right).