technetium-tc-99m-bicisate and Cerebral-Arterial-Diseases

Resting- and acetazolamide (Acz)-activated-regional cerebral blood flow (rCBF) measurements were performed by consecutive single-photon emission computed tomography (SPECT) studies before and after Acz administration using equal-volume-split technetium-99m-L,L-ethyl cysteinate dimer. Quantitative rCBF images were converted from qualitative axial SPECT images by the application of Patlak plot graphical analysis with radionuclide angiography and Lassen's linearization correction. Total time span required for this study was 53 minutes. The unaffected side of 37 studies with unilateral vascular lesions and 45 studies without apparent vascular lesions showed 132 +/- 17% and 140 +/- 15% increase of mean CBF (mCBF), respectively, under Acz administration. Comparing these values, the Acz-activated rCBF increases of less-affected and affected hemispheres of 23 studies with bilateral vascular lesions (116 +/- 13% and 113 +/- 12%, respectively) was lower with high statistical significance (P < 0.001). For the other 20 cases, physiologic saline was administered instead of Acz. This group showed no changes in mCBF under placebo administration (after placebo/baseline; 100 +/- 6%). Acetazolamide-activated rCBF increase was recognized clearly and easily using quantitative images. This noninvasive method is easy to perform and may be helpful to detect regional abnormalities of hemodynamic reserve in cerebrovascular diseases.

Topics: Acetazolamide; Adult; Aged; Arterial Occlusive Diseases; Carotid Stenosis; Cerebral Arterial Diseases; Cerebrovascular Circulation; Child; Circle of Willis; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Placebos; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Misery perfusion is defined as marginally sufficient cerebral blood supply relative to cerebral metabolic demand. The aim of the present study was to determine the optimal brain Tc-ethyl cysteinate dimer (ECD) SPECT imaging and analysis to detect misery perfusion on O PET imaging in patients with chronic occlusive disease of unilateral internal carotid or middle cerebral artery (MCA).. For 97 patients, cerebral blood flow, cerebral metabolic rate of oxygen, and oxygen extraction fraction were measured using O PET; Tc-ECD SPECT was performed using dynamic scanning with a scan duration of 10 minutes each for 50 minutes after tracer administration. A region of interest was placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres in all standardized images using a 3-dimensional stereotaxic region-of-interest template and affected-to-contralateral asymmetry ratio in the MCA territory (ARMCA) and contralateral-to-affected asymmetry ratio in the cerebellar hemisphere (ARcbl) were calculated.. The ARMCA or ARcbl on Tc-ECD SPECT with a scan time of 20 to 30 minutes after tracer administration (ARMCA20-30 or ARcbl20-30) was correlated with ARMCA on PET cerebral blood flow (r = 0.654) or ARMCA on PET cerebral metabolic rate of oxygen (r = 0.576), respectively, more strongly than with other scan times. The area under the receiver operating characteristic curve for detecting abnormally elevated ARMCA on PET oxygen extraction fraction was significantly greater for ARcbl20-30/ARMCA20-30 (0.947) than for ARMCA20-30 alone (0.780) (difference between areas, 0.167; P = 0.0001) on Tc-ECD SPECT.. Combination of asymmetries in the cerebellar and cerebral hemispheres on Tc-ECD SPECT in a scan time of 20 to 30 minutes after tracer administration optimally detects misery perfusion in unilateral internal carotid artery or MCA occlusive disease.

Topics: Adult; Aged; Arterial Occlusive Diseases; Brain; Cerebral Arterial Diseases; Cerebrovascular Circulation; Chronic Disease; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oxygen Radioisotopes; Positron-Emission Tomography; Tomography, Emission-Computed, Single-Photon