title: Brain single-photon emission CT studies using 99mTc-HMPAO and 99mTc-ECD early after recanalization by local intraarterial thrombolysis in patients with acute embolic middle cerebral artery occlusion.
abstract: OBJECTIVE
  The brain distribution of 9mTc-hexamethylpropyleneamine oxime (HMPAO) correlates with regional brain perfusion, whereas 99mTc-ethyl cysteinate dimer (ECD) reflects not only perfusion but also the metabolic status of brain tissue. We compared 99mTc-ECD single-photon emission CT (SPECT) with 99mTc-HMPAO SPECT early after recanalization by local intraarterial thrombolysis (LIT) in patients with acute embolic middle cerebral artery occlusion. We also assessed the predictive value of 99mTc-HMPAO and 99mTc-ECD SPECT for the development of ischemic brain damage.
  
  
  METHODS
  99mTc-HMPAO and consecutive 99mTc-ECD SPECT studies were performed in 15 patients within 3 hours of LIT. The two SPECT studies were obtained independently using a subtraction technique. SPECT evaluation was performed using semiquantitative region-of-interest analysis. Noninfarction, infarction, and hemorrhage were identified by follow-up CT or MR imaging.
  
  
  RESULTS
  Forty-five lesions were identified (21 noninfarctions, 19 infarctions, and five hemorrhages). Regardless of 99mTc-HMPAO SPECT findings, lesions showing isoactivity (count rate densities of 0.9 to 1.1 as compared with the contralateral side) on 99mTc-ECD SPECT were salvaged. Lesions with hypoactivity (values < 0.9) on 99mTc-ECD SPECT developed irreversible brain damage. Hemorrhage appeared in lesions with both hyperactivity (values > 1.1) on 99mTc-HMPAO SPECT and hypoactivity on 99mTc-ECD SPECT.
  
  
  CONCLUSIONS
  The brain distribution of 99mTc-ECD in a reperfused area identified by 99mTc-HMPAO SPECT early after recanalization of acute ischemic stroke is dependent on cerebral tissue viability. By combining 99mTc-ECD and 99mTc-HMPAO SPECT, performed within the first few hours of LIT, it is possible to identify patients at risk for hemorrhagic transformation reliably.
authors.affiliation: Department of Neurosurgery and the Cyclotron Research Center, Iwate Medical University, Morioka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ogasawara
authors.forename: A
authors.initials: A
authors.lastname: Ogawa
authors.forename: M
authors.initials: M
authors.lastname: Ezura
authors.forename: H
authors.initials: H
authors.lastname: Konno
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Yoshimoto
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000209:etiology; D002544:Cerebral Infarction / Q000175:diagnosis / Q000209:etiology; D003545:Cysteine / Q000031:analogs & derivatives*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D007269:Injections, Intra-Arterial; D020766:Intracranial Embolism / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: D005343:Fibrinolytic Agents; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime; C059659:technetium Tc 99m bicisate; D003545:Cysteine