• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.279-282
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• 1996

Sequential brain SPECT imaging has been used to assess the cerebral perfusion reserve(CPR) in cerebrovascular diseases(CVD). We have realized a parametric images of CPR using normalized difference ratio and deadtime correction. For the anatomical localization of CPR, the parametric images were registered to the contours of the cerebral regions using optimal threshold method. The parametric imags reflected the CPR more reliably and distinctively. We conclude that the qunatitative estimation of CPR using normalized difference ratio image could be useful for the diagnosis and assessment of postoperative prognosis in CVD.

• Korean Journal of Radiology
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• v.2 no.1
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• pp.1-7
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• 2001

Objective: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. Materials and Methods: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2^*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calculated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. Results: Mean rCBV ratios were 4.90°±1.01 for glioblastomas, 3.97°±0.56 for anaplastic gliomas and 1.75°±1.51 for low-grade gliomas, and were thus significantly different; p < .05 between glioblastomas and anaplastic gliomas, p < .05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblastomas and low-grade gliomas. The rCBV ratio cutoff value which permitted discrimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. Conclusion: Perfusion MR imaging is a useful and reliable technique for estimating the histologic grade of gliomas.

• Korean Journal of Radiology
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• v.22 no.3
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• pp.395-404
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• 2021

Objective: To compare the utility of computed tomography perfusion (CTP) and three different 4-point scoring systems in computed tomography angiography (CTA) in confirming brain death (BD) in patients with and without skull defects. Materials and Methods: Ninety-two patients clinically diagnosed as BD using CTA and/or CTP for confirmation were retrospectively reviewed. For the final analysis, 86 patients were included in this study. Images were re-evaluated by three radiologists according to the 4-point scoring systems that consider the vessel opacification on 1) the venous phase for both M4 segments of the middle cerebral arteries (MCAs-M4) and internal cerebral veins (ICVs) (A60-V60), 2) the arterial phase for the MCA-M4 and venous phase for the ICVs (A20-V60), 3) the venous phase for the ICVs and superior petrosal veins (ICV-SPV). The CTP images were independently reviewed. The presence of an open skull defect and stasis filling was noted. Results: Sensitivities of the ICV-SPV, A20-V60, A60-V60 scoring systems, and CTP in the diagnosis of BD were 89.5%, 82.6%, 67.4%, and 93.3%, respectively. The sensitivity of A20-V60 scoring was higher than that of A60-V60 in BD patients (p < 0.001). CTP was found to be the most sensitive method (86.5%) in patients with open skull defect (p = 0.019). Interobserver agreement was excellent in the diagnosis of BD, in assessing A20-V60, A60-V60, ICV-SPV, CTP, and good in stasis filling (κ: 0.84, 0.83, 0.83, 0.83, and 0.67, respectively). Conclusion: The sensitivity of CTA confirming brain death differs between various proposed 4-point scoring systems. Although the ICV-SPV is the most sensitive, evaluation of the SPV is challenging. Adding CTP to the routine BD CTA protocol, especially in cases with open skull defect, could increase sensitivity as a useful adjunct.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.721-722
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• 2002

The aim of this work is to analyze changes in cerebral hemodynamics and intracranial pressure mediated by cerebral blood flow challenges in patients with acute heart arrest. Lumped parameter model with feedback mechanism is utilized to simulate the hemodynamics of brain blood flow in case 40 min T-PLS operation is applied to patients of cardiac arrest. Numerical solutions show that cerebral blood flow and perfusion pressure in patients of cardiac arrest are sharply recovered in the initial state of T-PLS operation.

• Journal of Yeungnam Medical Science
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• v.11 no.1
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• pp.49-54
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• 1994

Postoperative brain damage is one of most serious complications of cardiopulmonary bypass (CPB). To prevent brain damage during CPB, adequate cerebral perfusion for cerebral oxygen demand should be maintained. This study monitored jugular venous oxyhemoglobin saturation ($SjO_2$), which reflects the overall balance of cerebral oxygen supply and demand, intermittently in 10 patients undergoing cardiac surgery. At the initiation of CPB, in spite of a significant decrease in mean arterial pressure, $SjO_2$ did not change, and it was stable during the hypothermic period of CPB. But a significan reduction in $SjO_2$ was observed during the rewarming period, and $SjO_2$ had an inverse linear correlation with esophageal temperature. Furthermore, the percent decrease of $SjO_2$ was related to rewarming speed. Therefore, therapeutic approaches for $SjO_2$ desaturation include slower rewarming, increasing cerebral blood flow, decreasing the cerebral metabolic rate for oxygen, increasing oxygen content, and increasing perfusion flow rate.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.26-32
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• 1992

Minimal deterioration of cerebral perfusion or microanatomical changes were undetectable on conventional Brain CT or MRI. So evaluation of focal functional changes of the brain parenchyme is essential in chronic head injury patients, who did not show focal anatomical changes on these radiological studies. However, the patients who had longstanding neurologic sequelae following head injury, there had been no available imaging modalities for evaluating these patients precisely. Therefore we tried to detect the focal functional changes on the brain parenchyme using $^{99m}Tc-HMPAO$ Brain SPECT on the patients of chronic head injuries. Twenty three patients who had suffered from headache, memory dysfunction, personality change and insomnia lasting more than six months fellowing head injury were included in our cases, which showed no anatomical abnormalities on Brain CT or MRI. At first they underwent psychological test whether the symptoms were organic or not. Also we were able to evaluate the cerebral perfusion changes with $^{99m}Tc-HMPAO$ Brain SPECT in 22 patients among the 23, which five patients were focal and 17 patients were nonfocally diffuse perfusion changes. Thus we can predict the perfusion changes such as local vascular deterioration or functional defects using $^{99m}Tc-HMPAO$ Brain SPECT in the patients who had suffered from post-traumatic sequelae, which changes were undetectable on Brain CT or MRI.

• Investigative Magnetic Resonance Imaging
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• v.5 no.2
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• pp.130-137
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• 2001

Purpose : Our purpose was to compare maximum relative cerebral blood volume (rCBV) with histologic grade of cerebral gliomas. Materials and methods : First-pass perfusion MR imaging was performed preoperatively in 16 patients with pathologically proven cerebral gliomas (7 glioblastoma, 2 anaplastic astrocytoma, 1 anaplastic oligodendroglioma, 5 low-grade astrocytoma, and 1 low-grade oligodendroglioma). Maximum rCBV was compared with histologic diagnosis and grade of the tumor. Results : Maximum rCBVs of glioblastomas were in the range of 433% to-1330% (average, 790 %), as compared with those of contra-lateral normal white matters. Maximum rCBVs of two non-enhancing anaplastic astrocytomas were 66% and 284%, respectively. Maximum rCBV of one well-enhancing anaplastic oligodendroglioma was 702%. Maximum rCBVs of low-grade astrocytomas were in the range of 80%-369% (average, 202%). Maximum rCBV of one low-grade oligodendroglioma was 1450%, even higher than those of glioblastomas. Conclusion : Maximum rCBV was higher in glioblastoma than in low-grade astrocytoma without overlapping. However, there was no difference of maximum rCBV between non-enhancing anaplastic astrocytoma and low-grade astrocrtoma.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.427-428
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• 2009

Optical imaging offers excellent spatio-temporal sensitivity that is unparalleled by any other perfusion based imaging techniques. We used in vivo optical recording of intrinsic signals (ORIS) to map neurovascular hemodynamics of perfusion, oximetry and membrane potential during epileptic events in rat and mouse neocortex. Studies of hemodynamic changes with ORIS alone were also performed in human. Laboratory studies in rodent epilepsy models have demonstrated a persistent increase in deoxygenated hemoglobin (Hbr) and a decrease in tissue oxygenation during interictal spikes and ictal events. This "epileptic dip", like the "initial dip" recorded during normal sensory processing, implies that the enormous rise in cerebral blood flow (CBF) is inadequate to meet the increased metabolic demands associated with synchronized epileptic activity. These findings are critically important to the interpretation of the perfusion-based imaging studies, such as fMRI. In addition, we visualized the effect of direct cortical electrical stimulation, an alterative epilepsy treatment. The optical data following direct cortical electrical stimulation showed that hemodynamic signals are sensitive to different electrical stimulation parameters. Furthermore, our recent data demonstrated that the application of unilateral electrical stimulation is able to elicit bilateral hemodynamic responses in rat neocortex.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.168-168
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• 2001

Purpose： Cerebral perfusion, as measured by interictal SPECT and PET, is known to be decreased in the affected hippocampus of the patients with hippocampal sclerosis. The purpose of th study is to evaluate the capability of perfusion MR imaging to demonstrate ipsilate hypopefusion in patients with hippocampal sclerosis.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.543-548
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• 1986

Massive air embolism during cardiopulmonary bypass is uncommon but serious and often lethal complication. Following this catastrophic event, the immediate institution of retrograde arterial blood perfusion via superior vena cava was made to remove air emboli from cerebral circulation. This method was performed by removing the arterial perfusion line from aortic cannula and connecting it to superior vena caval cannula. Then, retrograde perfusion at a flow rate of 2Umin via superior vena cava was carried out for 3 minutes. After air returning from the aortic cannula was identified, each line was connected to the cannulae primarily. In 2 cases who had massive air emboli due to air pumping into arterial line, the postoperative complete recovery resulted from this technique, which was used in conjunction with other therapy postoperatively.