• Korean Journal of Clinical Laboratory Science
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• v.36 no.1
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• pp.64-68
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• 2004

Brain death is defined as the irreversible cessation of all brain function. The diagnosis of brain death is primarily based on a careful neurological examination demonstrating unresponsiveness, absent of brain stem reflexes, and no respiratory activity. Several conditions which may mimic brain death must be excluded. In some cases investigations such as electroencephalography, angiography, transcranial doppler or evoked potentials can contribute to the diagnosis. The brief review will introduce medical technologist and clinician to the key issues in the definition and management of brain death.

• The Journal of Internal Korean Medicine
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• v.21 no.5
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• pp.805-811
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• 2000

Objectives : To determine the effects on blood flow of vertebrobasal vascular system in cerebral infarction, Methods : We altered 33 normal patients and 12 patients who were diagnosed cerebral infarction on Rt. middle cerebral artery(MCA) region and 8 patients who were diagnosed cerebral infarction on Lt, MCA region, and measured the mean velocity, systolic to diastolic rate(SD rate), asymmetrical index(A/I) by TCD. Results : The mean velocity of posterior cerebral artery(PCA), vertebral artery was increased in same direction as infarcted site and the mean velocity of basal artery was more increased than control, and the SD rate of PCA, vertebral artery, basal artery was larger than control. The A/l of PCA, vertebral artery was revealed that mean velocity of vertebrobasal vascular system is increase the same direction as infarcted area. Conclusion : TCD examination within 7 days(acute stage) after stroke can help to predict the infarcted direction.

• Annals of Clinical Neurophysiology
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• v.14 no.1
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• pp.20-24
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• 2012

Background: Migraine patients can be sensitive to external or internal stimuli, such as light, noise, or hormonal changes. Using transcranial Doppler ultrasonography (TCD) with breath-holding method, we evaluated the changes of cerebrovascular reactivity (CVR) to hypercapnia in women with migraine without aura between fasting and postprandial period. Methods: Twelve women with migraine without aura and the same number of age and sex-matched healthy controls with no significant history of headache participated in this study. Using TCD examinations, we studied mean flow velocity in middle cerebral artery with better temporal window. Each subject was examined consecutively before and after a standard meal, together with serum glucose level and blood pressure. CVR was evaluated with breath-holding index (BHI). Results: Postprandial-BHI (mean+SD) was significantly higher than fasting-BHI (mean+SD) in patients group but not in controls (in patient group; postprandial-BHI=1.38, fasting-BHI=1.08, in control group; postprandial-BHI=1.25, fasting-BHI=1.18, P=0.021 and 0.239, respectively). After meal, serum glucose level was significantly enhanced but blood pressure was not in both groups. Serum glucose level of patients showed a tendency of mild positive correlation with BHIs (${\gamma}$=0.448, P=0.032). Conclusions: Although exact mechanisms are unclear, cerebrovascular reactivity of some women with migraine without aura may be influenced by prandial state.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.64-69
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• 1999

Background : Syncope was defined as transient loss of consciousness and postural tone. The mechanisms of changes in cerebral hemodynamics during syncope have not been fully evaluated. Transcranial Doppler Ultrasonography can continuously monitor the changes in cerebral hemodynamics during head-up tilt (HUT). TCD could reveal the different patterns of changes in cerebral hemodynamics during syncope. Syncope without hypotension or bradycardia could be detected by TCD. We investigated the changes in cerebral blood flow velocity during HUT using TCD in 33 patients with a history of recurrent syncope or presyncope of unknown origin. Methods & Results : The positive responses were defined as presyncope or syncope with hypotension, bradycardia, or both. During HUT without isoproterenol infusion, there were a $86{\pm}23%$ drop in DV and a $41{\pm}34%$ drop in SV in 5 patients with positive reponses, and mean changes in those were less than 10% in patients with negative reponses (p=.00, p=.00). During HUT with isoproterenol infusion, TCD showed a $80{\pm}18%$ drop in diastolic velocity in 14 patients with positive reponses, and a $47{\pm}10%$ drop in that in patients with negative reponses (p=.00), however the change in systolic velocity did not differ. TCD showed three patterns during positive responses; loss of all flow, loss of end diastolic flow, and a decrease in diastolic velocity. Loss of consciousness occurred in the patients with loss of all flow or end-diastolic flow during positive reponses. Conclusions : TCD shows different patterns of changes in cerebral hemodynamics during HUT. TCD can be used to investigate the pathophysiology of neurocardiogenic syncope.

• Journal of Korean Neurosurgical Society
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• v.39 no.1
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• pp.20-25
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• 2006

Objective : The authors analyze prospectively the result of transcranial doppler[TCD] in normal pressure hydrocephalus and compared its cerebral blood flow parameters to radionuclide cerebrospinal fluid[CSF] flow study, postoperative brain computed tomography[CT] findings and clinical outcome, and studied the relationship between cerebral hemodynamics and clinical performance. Methods : Twenty five patients with hydrocephalus undertook pre- and post-operative TCD but only preoperative CSF flow study was performed. Mean flow velocity[Vm], pulsatility index[PI] and resistance index[RI] were assessed through TCD and changes in ventricle size and cortical gyral atrophy were checked through brain CT. Results : Postoperative hydrocephalus showed an increase in Vm[ACA P=0.037, MCA P=0.034], decrease in PI[ACA P=0.019, MCA P=0.017] and decrease in RI [ACA P=0.017, MCA P=0.021] compared to preoperative TCD parameters in the postoperative improvement group. In the postoperative improvement group, postoperative TCD parameters correlated with CSF flow study grade [Vm : $R^2=-0.75$, PI : $R^2=0.86$, RI : $R^2=0.78$] and ventriculocranial ratio change correlated with PI change [$R^2=0.73$]. The convexity gyral atrophy and initial TCD parameters showed close relationship to outcome. Conclusion : PI and RI can be used as an indicator of post operative prognosis, and with the addition of CSF flow study values, can also be used as a tool to predict pre-op and post-op patient status and successful shunt surgery.

• Biomedical Science Letters
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• v.15 no.1
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• pp.17-23
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• 2009

The prevalence of patent foramen ovale (PFO) in healthy persons was estimated as about $10{\sim}25%$ and was up to 40% in patients with stroke. Transesophageal echocardiography (TEE) was considered to be the most sensitive method to detect PFO and was used as the gold standard. Transcranial doppler sonography (TCD) of the middle cerebral artery (MCA) during a contrast (saline bubble) injection has recently been proposed as an alternative detecting method for PFO. In this study, we would like to know the difference between TCD value and TEE value in subjects with cryptogenic ischemic stroke. We performed TCD and TEE tests to detect PFO on 64 patients (30 women and 34 men, mean age was 59.4 years) with cryptogenic ischemic stroke. PFO prevalence through TCD was 45.3% (29 of 64 patients) and the prevalence through TEE was 34.4% (22 of 64 patients). There was no statistical significance between PFO test and TCD test (P=0.206). But TCD had a sensitivity of 90.9% (20 of 22 patients), specificity of 78.6% (33 of 42 patients), positive predictive value of 69.0% (20 of 29 patients), and negative predictive value of 94.3% (33 of 35 patients). We concluded that TCD was a highly sensitive method for detecting a right-left shunt. Therefore, the non-invasive TCD test is a method more effective than the anti-invasive TEE test in the cost and evaluation of the existence or nonexistence of right to left shunt in addition to the screening method of the cerebrovascular disorder. Considering these points, TCD test could be recommended for patients with cryptogenic ischemic stroke as a useful and convenient method for screening of the existence or nonexistence of a right to left shunt caused by PFO.

• Journal of Chest Surgery
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• v.49 no.1
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• pp.22-28
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• 2016

Background: Carotid endarterectomy (CEA) with selective shunting is the surgical method currently used to treat patients with carotid artery disease. We evaluated the incidence of major postoperative complications in patients who underwent CEA with selective shunting under transcranial Doppler (TCD) at our institution. Methods: The records of 45 patients who underwent CEA with TCD-based selective shunting under general anesthesia from November 2009 to June 2015 were reviewed. The risk factors for postoperative complications were analyzed using univariate and multivariate analysis. Results: Preoperative atrial fibrillation was observed in three patients. Plaque ulceration was detected in 10 patients (22.2%) by preoperative computed tomography imaging. High-level stenosis was observed in 16 patients (35.5%), and 18 patients had contralateral stenosis. Twenty patients (44.4%) required shunt placement due to reduced TCD flow or a poor temporal window. The 30-day mortality rate was 2.2%. No cases of major stroke were observed in the 30 days after surgery, but four cases of minor stroke were noted. Univariate analysis showed that preoperative atrial fibrillation (odds ratio [OR], 40; p=0.018) and ex-smoker status (OR, 17.5; p=0.021) were statistically significant risk factors for a minor stroke in the 30-day postoperative period. Analogously, multivariate analysis also found that atrial fibrillation (p<0.001) and ex-smoker status (p=0.002) were significant risk factors for a minor stroke in the 30-day postoperative period. No variables were identified as risk factors for 30-day major stroke or death. No wound complications were found, although one (2.2%) of the patients suffered from a hypoglossal nerve injury. Conclusion: TCD-based CEA is a safe and reliable method to treat patients with carotid artery disease. Preoperative atrial fibrillation and ex-smoker status were found to increase the postoperative risk of a small embolism leading to a minor neurologic deficit.

• Journal of Chest Surgery
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• v.50 no.6
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• pp.448-452
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• 2017

Background: Proper monitoring of cerebral perfusion during carotid artery surgery is crucial for determining if a shunt is needed. We compared the safety and reliability of near-infrared spectroscopy (NIRS) w ith transcranial Doppler (TCD) for cerebral monitoring. Methods: This single-center, retrospective review was conducted on patients who underwent carotid endarterectomy (CEA) using selective shunt-based TCD or NIRS at Daegu Catholic University Medical Center from November 2009 to June 2016. Postoperative complications were the primary outcome, and the distribution of risk factors between the 2 groups was compared. Results: The medical records of 74 patients (45 TCD, 29 NIRS) were reviewed. The demographic characteristics were similar between the 2 groups. One TCD patient died within the 30-day postoperative period. Postoperative stroke (n=4, p=0.15) and neurologic complications (n=10, p=0.005) were only reported in the TCD group. Shunt usage was 44.4% and 10.3% in the TCD and NIRS groups, respectively (p=0.002). Conclusion: NIRS-based selective shunting during CEA seems to be safe and reliable for monitoring cerebral perfusion in terms of postoperative stroke and neurologic symptoms. It also reduces unnecessary shunt usage.

• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.923-928
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• 2000

Objective : The reliability of transcranial doppler sonography(TCD) for predicting delayed ischemic neurologic deficit( DIND) was investigated in patients with aneurysmal subarachnoid hemorrhage(SAH). Methods : The velocity of blood flow through the middle cerebral artery was measured by TCD in 70 patients treated surgically within 72 hours due to ruptured cerebral aneurysm. A correlation between measured maximal mean blood flow velocities and clinical factors including age, hypertension, Hunt-Hess grade, Fisher grade, DIND, and outcome was made. Results : An age-dependent reduction of the measured maximal mean velocities was found(r＝-0.4043, p<0.001). Flow velocities in hypertensive patients were significantly lower than in the normotensive individuals(two-tailed T test, p<0.05). There was no significant difference between the flow velocities and evaluated other clinical factors. When the flow velocities of 14 patients who developed DIND were compared with those of patients without deficits, no significant difference was seen. A significant increase in flow velocities in the days before the onset of DIND was found only in 4 of 14 cases. High flow velocities did not necessarily mean impending neurological deficits : 6 of 70 patients tolerated flow velocities over 160cm/s. Conclusion : We suggest that TCD readings have limited utility for predicting DIND following SAH, especially in older or hypertensive patients. More direct measurements of blood flow are necessary to adequately predict which patients are at high risk of DIND.

• Journal of Oriental Neuropsychiatry
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• v.15 no.2
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• pp.173-180
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• 2004

Objectives : The purpose of this study is to investigate the change of cerebral blood flow velocity by different types of suggestion in normal subject. Methods : Suggestion of ascending qi inducement and descending qi inducement which were recomposed from autogenic training, was operated on 60 normal subjects individually. Then cerebral blood flow velocity was examined by Transcranial doppler ultrasonography(TCD) each 5 minutes before and after suggestion. Results : The result shows that cerebral blood flow(CBF) velocity was increased significantly in suggestion of ascending qi inducement and CBF velocity was decreased significally after 1 minute in suggestion of descending qi inducement. Conclusion : Suggestion could have affected to CBF velocity, and also different types of suggestion could have affected to the change of brain blood flow. Various clinical studies should be completed on patients in the future.