- Email: [email protected]
WS1 Polysomnography
S16
Workshops Workshop 1. Polysomnography WS1 Polysomnography Jee Hyun Kim1 *, Visasiri Tantrakul2 * 1 Dept. of Neurology, Dankook University College of Medicine, Korea, 2 Dept. of Pulmonary Medicine, Chulalongkorn University School of Medicine, Thailand E-mail address: [email protected] This workshop will review the role of polysomnography (PSG) in diagnosing sleep disorders, technical aspects of PSG application and the typical PSG findings of common sleep disorders. Sleep is composed of REM (rapid eyeball movement) sleep and non-REM sleep, distinguished by the combination findings of electroencephalography, electro-oculogram and chin electromyogram. Besides the sleep stages, more information during sleep are obtained with polysomnography, such as breathing during sleep, periodic leg movements and the presence of normal REM sleep atonia. Basic PSG scoring rules of sleep stage, arousal, breathing and leg movements will be briefly reviewed. Common sleep disorder cases will be presented. The contents presented will help physicians and technicians seek an introduction to or review the basics of polysomnography. Workshop 2. Transcranial Doppler Sonography WS2.1 TCD Diagnosis of Intracranial Stenosis: Technique and Interpretation Yong-Seok Lee * Dept. of Neurology, College of Medicine, Seoul National University, Seoul National University Metropolitan Boramae Hospital, Korea E-mail address: [email protected] Transcranial Doppler ultrasonography (TCD) is a noninvasive real-time neuroimaging modality for the evaluation of characteristics of blood flow in basal intracerebral vessels. It is useful for the diagnosis and monitoring of stenosis/occlusion, recanalization of intracranial vessels, vasomotor reactivity testing, emboli monitoring, and right-to-left shunt detection in patients with ischemic stroke. It is also useful for detecting increased intracranial pressure and confirming cerebral circulatory arrest. TCD is of established value for screening children with sickle cell disease and detecting and monitoring vasospasm after spontaneous subarachnoid hemorrhage. To evaluate stenosis more accurately, application of standard technique and interpretation with optimal diagnostic criteria are mandatory. A standard examination should be applied to whole vessels through temporal, orbital, and suboccipital window. To shorten the time of examination, maximum power and large sample volume are recommended. Stenosis of middle cerebral artery (MCA), carotid siphon (ICAs), and basilar artery (BA) may be accurately diagnosed with substantial sensitivity and specificity (85 95%). In addition to elevated mean flow velocity criteria (>80 100 cm/s), asymmetry index (>30%) or M2/M1 ratio (>1.05) enhances diagnostic accuracy (specificity > 96%). Anatomical variation of unilateral hypoplasia or aplasia may be considered in anterior cerebral artery (ACA) and vertebral artery (VA) interpretation. TCD results should be interpreted cautiously for the diagnosis of intracranial stenosis. Various TCD parameters (MFV, PI, associated findings), age, risk factors, clinical profiles, and possibility of anatomical variations should be considered comprehensively for better diagnostic accuracy. WS2.2 Transcranial Doppler Ultrasonography: Examination Techniques and Clinical Applications Disya Ratanakorn Division of Neurology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand E-mail address: [email protected] Transcranial Doppler ultrasonography (TCD) is an non-invasive method to evaluate hemodynamics of intracranial vessels at the Circle of Willis.
Invited Speakers: Workshops A low frequency, 2 MHz pulse Doppler, transducer is used and the intracranial vessels are insonated through acoustic windows at temporal, orbital and suboccipital windows. The middle cerebral, anterior cerebral, and posterior cerebral arteries are insonated through temporal window at the thin portion of the temporal bone above the zygomatic arch. The ophthalmic artery and carotid siphon can be evaluated through orbital window whereas the intracranial vertebral artery and basilar artery can be examined through suboccipital window via foramen magnum. The time averaged mean-maximum velocity is most often used to classify intracranial stenosis. A zero angle of insonation is assumed for calculation of flow velocity in conventional, blind, TCD in contrast to anglecorrected mean flow velocity used in transcranial color-coded duplex ultrasonography. The angle-corrected flow velocity is usually 10% higher than an assuming zero angle flow velocity. Transducers can be easily affixed with headbands, allowing for real-time monitoring of intracranial hemodynamic changes during evoked flow testing, or when monitoring for cerebral emolization. The TCD interpretation is based on the flow velocity criteria. The first established clinical use for TCD was to identify cerebral vasospasm after subarachnoid hemorrhage. Clinical indications for TCD include screening for intracranial stenosis/occlusion, vasospasm, collateral flow and hemodynamics of the intracranial circulation due to either intra- or extra-cranial cerebrovascular stenosis or occlusion, in the carotid or vertebrobasilar vessels. It can also identify cerebral hemodynamic changes with evoked flow, physiological testing such as inhalation of carbon dioxide, breath holding, or diamox intravenous injection to evaluate the cerebral vasoreactivity implying to cerebral reserve capacity. TCD monitoring can identify cerebral embolization such as during cardiopulmonary bypass, carotid endarterectomy, carotid stenting, for identifying right to left intra- and extra-cardiac shunts using agitated saline intravenous injection, and distal embolization from carotid artery stenosis and middle cerebral artery stenosis. TCD is now also being used to assess the intracranial circulation in acute stroke to provide additional information related to the use of thrombolytic therapy including ultrasound thrombolysis. TCD should be used in combination with carotid and vertebral duplex ultrasonography to evaluate the complete cerebral circulation in the patient with stroke and TIA. Another important use of TCD is to screen the patients with sickle cell disease who need transfusion therapy to prevent stroke. Additonal uses of TCD are increasing such as subclavian steal, sleep apnea, migraine and cerebral venous thrombosis. WS2.3 Transcranial Doppler Sonography Jun Hong Lee * Dept. of Neurology, National Health Insurance Corporation Ilsan Hospital, Korea E-mail address: [email protected] Background: In 1965, Aaslid and colleagues [1] developed a transcranial Doppler (TCD) device with a pulsed wave sound emission of 2 MHz that could successfully penetrate the skull and accurately measure blood flow velocities in the basal arteries of the circle of Willis. With the introduction of TCD, it became possible to record intracranial blood flow velocity directly, and TCD became an important noninvasive method for assessing cerebral hemodynamics and for evaluating intracranial cerebrovascular disease. TCD Examination: In general, it is most convenient to start with transtemporal insonation, to identify the MCA on either side at an insonation depth of 50 to 55 mm, and then to track the ipsilateral arterial network, step by step, in various directions. Proof of traceability of the MCA is necessary for its unequivocal identification. This is also true for other arteries at the base of the brain. Traceability refers to the fact that the MCA (and usually other arteries) can be tracked in incremental steps from a shallower insonation depth (35 mm) to deeper sites (55 mm) without changes in the character of the flow profile and flow direction. When tracking the MCA medially (65 70 mm), an abrupt change in flow direction (away from, rather than toward the probe) indicates insonation of the A1 segment of the ACA. Flow signals toward the probe at this depth usually emanate from the carotid siphon at its junction with the MCA [2]. By angling the beam more posteriorly from a transcranial approach, the P1 segment of the PCA can be picked up most readily at an insonation depth of 65 to 70 mm. The PCA can then be tracked to the BA (75 mm) and from there to the contralateral PCA (80 85 mm). The two criteria of
Workshops Workshop 1. Polysomnography WS1 Polysomnography Jee Hyun Kim1 *, Visasiri Tantrakul2 * 1 Dept. of Neurology, Dankook University College of Medicine, Korea, 2 Dept. of Pulmonary Medicine, Chulalongkorn University School of Medicine, Thailand E-mail address: [email protected] This workshop will review the role of polysomnography (PSG) in diagnosing sleep disorders, technical aspects of PSG application and the typical PSG findings of common sleep disorders. Sleep is composed of REM (rapid eyeball movement) sleep and non-REM sleep, distinguished by the combination findings of electroencephalography, electro-oculogram and chin electromyogram. Besides the sleep stages, more information during sleep are obtained with polysomnography, such as breathing during sleep, periodic leg movements and the presence of normal REM sleep atonia. Basic PSG scoring rules of sleep stage, arousal, breathing and leg movements will be briefly reviewed. Common sleep disorder cases will be presented. The contents presented will help physicians and technicians seek an introduction to or review the basics of polysomnography. Workshop 2. Transcranial Doppler Sonography WS2.1 TCD Diagnosis of Intracranial Stenosis: Technique and Interpretation Yong-Seok Lee * Dept. of Neurology, College of Medicine, Seoul National University, Seoul National University Metropolitan Boramae Hospital, Korea E-mail address: [email protected] Transcranial Doppler ultrasonography (TCD) is a noninvasive real-time neuroimaging modality for the evaluation of characteristics of blood flow in basal intracerebral vessels. It is useful for the diagnosis and monitoring of stenosis/occlusion, recanalization of intracranial vessels, vasomotor reactivity testing, emboli monitoring, and right-to-left shunt detection in patients with ischemic stroke. It is also useful for detecting increased intracranial pressure and confirming cerebral circulatory arrest. TCD is of established value for screening children with sickle cell disease and detecting and monitoring vasospasm after spontaneous subarachnoid hemorrhage. To evaluate stenosis more accurately, application of standard technique and interpretation with optimal diagnostic criteria are mandatory. A standard examination should be applied to whole vessels through temporal, orbital, and suboccipital window. To shorten the time of examination, maximum power and large sample volume are recommended. Stenosis of middle cerebral artery (MCA), carotid siphon (ICAs), and basilar artery (BA) may be accurately diagnosed with substantial sensitivity and specificity (85 95%). In addition to elevated mean flow velocity criteria (>80 100 cm/s), asymmetry index (>30%) or M2/M1 ratio (>1.05) enhances diagnostic accuracy (specificity > 96%). Anatomical variation of unilateral hypoplasia or aplasia may be considered in anterior cerebral artery (ACA) and vertebral artery (VA) interpretation. TCD results should be interpreted cautiously for the diagnosis of intracranial stenosis. Various TCD parameters (MFV, PI, associated findings), age, risk factors, clinical profiles, and possibility of anatomical variations should be considered comprehensively for better diagnostic accuracy. WS2.2 Transcranial Doppler Ultrasonography: Examination Techniques and Clinical Applications Disya Ratanakorn Division of Neurology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand E-mail address: [email protected] Transcranial Doppler ultrasonography (TCD) is an non-invasive method to evaluate hemodynamics of intracranial vessels at the Circle of Willis.
Invited Speakers: Workshops A low frequency, 2 MHz pulse Doppler, transducer is used and the intracranial vessels are insonated through acoustic windows at temporal, orbital and suboccipital windows. The middle cerebral, anterior cerebral, and posterior cerebral arteries are insonated through temporal window at the thin portion of the temporal bone above the zygomatic arch. The ophthalmic artery and carotid siphon can be evaluated through orbital window whereas the intracranial vertebral artery and basilar artery can be examined through suboccipital window via foramen magnum. The time averaged mean-maximum velocity is most often used to classify intracranial stenosis. A zero angle of insonation is assumed for calculation of flow velocity in conventional, blind, TCD in contrast to anglecorrected mean flow velocity used in transcranial color-coded duplex ultrasonography. The angle-corrected flow velocity is usually 10% higher than an assuming zero angle flow velocity. Transducers can be easily affixed with headbands, allowing for real-time monitoring of intracranial hemodynamic changes during evoked flow testing, or when monitoring for cerebral emolization. The TCD interpretation is based on the flow velocity criteria. The first established clinical use for TCD was to identify cerebral vasospasm after subarachnoid hemorrhage. Clinical indications for TCD include screening for intracranial stenosis/occlusion, vasospasm, collateral flow and hemodynamics of the intracranial circulation due to either intra- or extra-cranial cerebrovascular stenosis or occlusion, in the carotid or vertebrobasilar vessels. It can also identify cerebral hemodynamic changes with evoked flow, physiological testing such as inhalation of carbon dioxide, breath holding, or diamox intravenous injection to evaluate the cerebral vasoreactivity implying to cerebral reserve capacity. TCD monitoring can identify cerebral embolization such as during cardiopulmonary bypass, carotid endarterectomy, carotid stenting, for identifying right to left intra- and extra-cardiac shunts using agitated saline intravenous injection, and distal embolization from carotid artery stenosis and middle cerebral artery stenosis. TCD is now also being used to assess the intracranial circulation in acute stroke to provide additional information related to the use of thrombolytic therapy including ultrasound thrombolysis. TCD should be used in combination with carotid and vertebral duplex ultrasonography to evaluate the complete cerebral circulation in the patient with stroke and TIA. Another important use of TCD is to screen the patients with sickle cell disease who need transfusion therapy to prevent stroke. Additonal uses of TCD are increasing such as subclavian steal, sleep apnea, migraine and cerebral venous thrombosis. WS2.3 Transcranial Doppler Sonography Jun Hong Lee * Dept. of Neurology, National Health Insurance Corporation Ilsan Hospital, Korea E-mail address: [email protected] Background: In 1965, Aaslid and colleagues [1] developed a transcranial Doppler (TCD) device with a pulsed wave sound emission of 2 MHz that could successfully penetrate the skull and accurately measure blood flow velocities in the basal arteries of the circle of Willis. With the introduction of TCD, it became possible to record intracranial blood flow velocity directly, and TCD became an important noninvasive method for assessing cerebral hemodynamics and for evaluating intracranial cerebrovascular disease. TCD Examination: In general, it is most convenient to start with transtemporal insonation, to identify the MCA on either side at an insonation depth of 50 to 55 mm, and then to track the ipsilateral arterial network, step by step, in various directions. Proof of traceability of the MCA is necessary for its unequivocal identification. This is also true for other arteries at the base of the brain. Traceability refers to the fact that the MCA (and usually other arteries) can be tracked in incremental steps from a shallower insonation depth (35 mm) to deeper sites (55 mm) without changes in the character of the flow profile and flow direction. When tracking the MCA medially (65 70 mm), an abrupt change in flow direction (away from, rather than toward the probe) indicates insonation of the A1 segment of the ACA. Flow signals toward the probe at this depth usually emanate from the carotid siphon at its junction with the MCA [2]. By angling the beam more posteriorly from a transcranial approach, the P1 segment of the PCA can be picked up most readily at an insonation depth of 65 to 70 mm. The PCA can then be tracked to the BA (75 mm) and from there to the contralateral PCA (80 85 mm). The two criteria of