Artikel
A comparative study of perfusion CT and 99mTc-HMPAO SPECT measurements to assess cerebrovascular reserve capacity in patients with internal carotid artery occlusion
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Veröffentlicht: | 20. Mai 2009 |
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Gliederung
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Objective: Patients with internal carotid artery (ICA) occlusion can demonstrate impaired cerebral vascular reserve (CVR). Today, to detect CVR single photon emission CT (SPECT) is widely accepted as predictor in the diagnostic pathway in patients considered for cerebral revascularization. Goal of the present study was to compare the results of perfusion CT (PCT) and 99mTc-HMPAO SPECT in patients with ICA occlusion.
Methods: Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), adapted time to peak (Tmax) and mean transit times (MTT) were compared with SPECT data.
Results: In thirteen patients comparable examinations were analyzed. 99mTc-HMPAO SPECT demonstrated an impairment of CVR in six studies. A preserved CVR was present in seven studies. PCT showed a delayed MTT (mean +3.8 s) and a delayed Tmax (mean +11.92 s) on the occluded side. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s) and a delayed Tmax (mean +5.9 s), (both p <0.005). 66% of patients with impaired CVR in SPECT showed a complete correlation of Tmax measurements in PCT. Tmax had a higher positive predictive value (PPV: 88.8%) than MTT (68.0%).
Conclusions: The prospective study demonstrated a highly significant correlation of perfusion parameters as detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for evaluation of cerebral perfusion in patients with ICA occlusion.