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.
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.
Ogasawara
K
K
Department of Neurosurgery and the Cyclotron Research Center, Iwate Medical University, Morioka, Japan.
Ogawa
A
A
Ezura
M
M
Konno
H
H
Suzuki
M
M
Yoshimoto
T
T
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
D005343:Fibrinolytic Agents; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime; C059659:technetium Tc 99m bicisate; D003545:Cysteine