• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.280-288
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• 2013

Objective : Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease. Methods : Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty. Results : The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study. Conclusion : PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.94-102
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• 2003

Purpose : Cerebral blood flow (CBF) reactivity to acetazolamide (ACZ) is useful to select patients with hemodynamic failure. However, it is still a matter of speculation that varying degrees of regional CBF increases after ACZ administration represent the severity or stage of regional hemodynamic failure as assessed by positron emission tomography (PET). We studied to elucidate whether ACZ challenge $^{123}I-IMP$ brain single photon emission tomography (SPECT) can accurately grade the seventy of regional hemodynamic failure. Materials and Methods: Eighteen patients (M: 16, F: 2, average age: 61 years) with unilateral occlusive disease of the internal carotid artery or the trunk of the middle cerebral artery (MCA). Patients undewent $^{123}I-IMP$ brain SPECT study with acetazolamide challenge and PET study was carried out within 2 weeks before and after SPECT study. Five healthy volunteers with a mean age of 48 years (range: 28-73 yr, M: 3, F: 2) underwent PET studies to determine normal values. In SPECT study, an asymmetry index (Al)-the percentage of radioactivity of region of interest (ROI) in the occlusive cerebrovascular lesion to the contralateral homologous ROI-was used for numerical evaluation of relative $^{123}I-IMP$ distribution. In PET study, regional CBF, oxygen extraction fraction (OEF), cerebral metabolic rate of oxygen ($CMRO_2$) and cerebral blood volume (CBV) values were measured with $^{15}O-labeled$ gas inhalation method and the values were used for comparison with Al (Al during acetazolamide challenge-Al of basal study) on the SPECT study. ROls were classified by severity into three groups (normal, stage I and stage II). Results: Mean values of Al in areas with normal, stage I and stage II hemodynamic failure were $6.25{\pm}7.77%\;(n=107),\;-10.38{\pm}10.41%\:(n=117)\;and\;13.30{\pm}10.51%\;(n=140)$, respectively. Al significantly differed with each groups (p<0.05). Correlation between Al and CBF, OEF and CBV/CBF in hemisphere with occlusive cerebrovascular lesion was 0.20 (p<0.01), -0.28 (p<0.01) and -0.28 (p<0.01), respectively. Conclusion: We concluded that $^{123}I-IMP$ brain SPECT with acetazolamide challenge could determine the severity ad stage of regional hemodynamic failure as assessed by PET.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.267-274
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• 2008

Purpose: Transient neurological deterioration (TND) is one of the complications after extracranial-intracranial bypass surgery, and it has been assumed to be caused by postoperative transient hyperperfusion. This study was performed to evaluate the relationship between TND and preoperative and postoperative cerebral perfusion status on brain perfusion SPECT following superficial temporal artery - middle cerebral artery (STA-MCA) anastomosis surgery. Materials and Methods: A total of 60 STA-MCA anastomosis surgeries of 56 patients (mean age: $50{\pm}16$ yrs; M:F=29:27; atherosclerotic disease: 33, moyamoya disease: 27) which were done between September 2003 and July 2006 were enrolled. The resting cerebral perfusion and cerebral vascular reserve (CVR) after acetazolamide challenge were measured before and 10 days after surgery using 99mTc-ethylcysteinate dimer (ECD) SPECT. Moreover, the cerebral perfusion was measured on the third postoperative day. With the use of the statistical parametric mapping and probabilistic brain atlas, the counts for the middle cerebral artery (MCA) territory were calculated for each image, and statistical analyses were performed. Results: In 6 of 60 cases (10%), TND occurred after surgery. In all patients, the preoperative cerebral perfusion of affected MCA territory was significantly lower than that of contralateral side (p=0.002). The cerebral perfusion on the third and tenth day after surgery was significantly higher than preoperative cerebral perfusion (p=0.001, p=0.02). In TND patients, basal cerebral perfusion and CVR on preoperative SPECT were significantly lower than those of non-TND patients (p=0.01, p=0.05). Further, the increases in cerebral perfusion on the third day after surgery were significant higher than those in other patients (p=0.008). In patients with TND, the cerebral perfusion ratio of affected side to contralateral side on third postoperative day was significantly higher than that of other patients (p=0.002). However, there was no significant difference of the cerebral perfusion ratio on preoperative and tenth postoperative day between patients with TND and other patients. Conclusion: In patients with TND, relative and moderate hyperperfusion was observed in affected side after bypass surgery. These finding may help to understand the pathophysiology of TND.