TY - JOUR T1 - Brain Single-photon Emission CT Studies Using <sup>99m</sup>Tc-HMPAO and <sup>99m</sup>Tc-ECD Early after Recanalization by Local Intraarterial Thrombolysis in Patients with Acute Embolic Middle Cerebral Artery Occlusion JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 48 LP - 53 VL - 22 IS - 1 AU - Kuniaki Ogasawara AU - Akira Ogawa AU - Masayuki Ezura AU - Hiromu Konno AU - Michiyasu Suzuki AU - Takashi Yoshimoto Y1 - 2001/01/01 UR - http://www.ajnr.org/content/22/1/48.abstract N2 - BACKGROUND AND PURPOSE: The brain distribution of 99mTc-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 &lt; 0.9) on 99mTc-ECD SPECT developed irreversible brain damage. Hemorrhage appeared in lesions with both hyperactivity (values &gt; 1.1) on 99mTc-HMPAO SPECT and hypoactivity on 99mTc-ECD SPECT.CONCLUSION: 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. ER -