Related Experiment Videos
Detection of postural cerebral hypoperfusion with technetium-99m-HMPAO brain SPECT in patients with cerebrovascular
K Hayashida1, Y Hirose, T Kaminaga
1Department of Radiology, Medical School, Osaka University, Japan.
Insights
Upright brain SPECT using 99mTc-HMPAO identified postural cerebral hypoperfusion in patients with internal carotid artery or middle cerebral artery occlusion. This technique may visualize silent cerebral ischemia.
Area of Science:
- Neurology
- Radiology
- Cerebrovascular Disease
Background:
- Internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis/occlusion affects cerebral blood flow.
- Postural changes can exacerbate hypoperfusion in cerebrovascular disease.
- Silent cerebral ischemia is a concern in patients with significant carotid disease.
Purpose of the Study:
- To investigate the utility of upright 99mTc-HMPAO brain SPECT in detecting postural cerebral hypoperfusion.
- To differentiate perfusion abnormalities in patients with ICA/MCA occlusion versus stenosis.
- To explore the relationship between postural hypoperfusion and silent cerebral ischemia.
Main Methods:
- 19 patients with ICA/MCA stenosis or occlusion underwent brain SPECT with 99mTc-HMPAO.
- Patients were studied in both supine and upright positions, with injection after arising.
- Patients were categorized into Group A (occlusion) and Group B (stenosis/endarterectomy).
Main Results:
- Additional perfusion abnormalities were found in 7/10 patients in Group A (occlusion) but only 1/9 in Group B (stenosis).
- Asymmetric ratios between upright and supine positions changed significantly in Group A (p < 0.01) but not in Group B.
- Postural cerebral hypoperfusion was relevant to ICA/MCA occlusion.
Conclusions:
- Upright 99mTc-HMPAO brain SPECT can visualize postural cerebral hypoperfusion.
- This finding may be related to silent cerebral ischemia in patients with ICA/MCA occlusion.
- The technique shows promise for evaluating cerebrovascular hemodynamics in specific patient groups.
Abstract:
Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.