Cerebrovascular Ultrasound in Stroke Prevention and Treatment

Description

Effective stroke therapy can be improved through real-time monitoring of the neurological and cardiovascular responses to treatment. This requires crucial knowledge on behalf of both the sonographer and stroke physician to make the best decisions for the patient so as to minimize the damage caused by the original stroke and the risk of further stroke. Cerebrovascular Ultrasound in Stroke Prevention and Treatment, Second Edition, takes a practical approach to the examination of patients, the interpretation of ultrasound studies and the application of cerebrovascular ultrasound in the development of management and treatment studies, assisting neurologists, radiologists, and ultrasonographers in stroke therapy. Cerebrovascular Ultrasound in Stroke Prevention and T r eatment Andrei V . Alexandrov MD, RVT SECOND EDITION Contents Part I How t o Perform Ultrasound T ests, 1 Part II Hemodynamic Principles, 4 5 Part III Criteria for Interpretation, 85 Part IV Ultrasound in Stroke Prevention and T r eatment, 145 List of Contributors Cindy J. Fuller PHD Zsolt G arami MD James C . G r o tta MD Mark R. Harrigan MD Jill T . Jesurum PHD Annabelle Lao MD Alan B . Lumsden MD Robert Mikulik MD, PHD David W . N ewell MD Fenwick T . Nichols III MD Paola Palazzo MD Joseph F . Polak MD, MPH Alice R obinson-Vaughn Robert J. Adams MD Anne W . Alexandrov PHD, F AAN Clotilde B alucani MD Andrew D. Barreto MD Joel Cure MD Andrew Demchuk MD, FRCPC Flemming Forsberg PHD Marta Rubiera, MD T atjana Rundek MD, PHD V ijay K . Sharma MD, RVT Georgios T sivgoulis MD, PHD, RVT Konstantinos V adikolias MD, PHD K.S. Lawrence W o ng MD Preface Foreword Neurosonology – d ead or alive? Alive and K icking! Preface to the First E dition Foreword to the First E dition Ultrasound: W hat’s in the W aveforms? Acknowledgment (First E dition) Practice of Ultrasound: an Introduction How to Perform Ultrasound T ests 1 Principles of Extracranial Ultrasound Examination Andrei V . Alexandrov 1 , Alice Robinson-Vaughn 1 , Clotilde Balucani 2 Introduction Anatomy of the cerebrovascular arterial system The common carotid artery The internal carotid artery The vertebral artery Components of ultrasound examination Continuous wave (CW) Doppler The external carotid artery Scanning direction RVA Mid-cervical VA Proximal cervical VA VA origin Insonation with CW probe The B -mode image T ransducer surface rectangular color flow box The c olor-flow Doppler image The power Doppler image The c olor velocity image B-Flow and c ompound imaging Harmonic imaging Doppler velocity s pectral d isplay Extracranial d uplex ultrasound examination technique and scanning prot Imaging in the transverse plane Imaging in the longitudinal p lane Color flow ultrasound evaluation of flow dynamics Doppler spectral evaluation of flow dynamics Tips for optimizing color flow set-up Extracranial d uplex examination should provide the following data Tips to improve accuracy References 2 Intracranial Cerebrovascular Ultrasound Examination T echniques Andrei V . Alexandrov 1 , Marta Rubiera 2 , Paola Palazzo 3 & Marsha Introduction TCD examination technique Where to start? Time axis 1 second Total sweep time approx. 5 sec T ranstemporal insonation steps (Figure 2 .5) T ransorbital insonation steps (Figure 2 .6) T ransforaminal insonation steps (Figure 2 .7) Submandibular insonation steps (Figure 2 .8) Practical advice M-mode or PMD/TCD examination technique A standard PMD/spectral TCD insonation protocol for an average-sized Transtemporal insonation Transorbital insonation Transforaminal i nsonation Useful rules to r emember Tips to improve accuracy The B -mode image The c olor Doppler image T ranscranial color duplex imaging Doppler spectral a nalysis TCDI examination technique Using the transtemporal window Using the foramenal window Using the orbital window Using the submandibular window Advantages o f T CDI o ver non-imaging techniques Limitations of TCDI References 3 Anatomy of the Brain’s Arterial Supply Joel Cure The aortic arch V ariant great vessel origins and aortic arch anomalies The anterior circulation Internal carotid artery segments Intracranial ICA branches Anterior cerebral artery Middle cerebral artery The posterior circulation Posterior c irculation branches Posterior cerebral artery Pial to pial anastomotic flow Primitive anastomoses The circle of Willis References Hemodynamic Principles 4 Integrated Assessment of Systemic and Intracranial Hemodynamics Anne W . Alexandrov Introduction Principles of blood flow The cardiac cycle Arterial perfusion and venous r eturn Intrinsic cardiac determinants of blood flow Neuro-endocrine mediation of cardiac output Bedside assessment o f systemic hemodynamics F ast Flush Square Wave Return to Waveform P AP waveform; balloon inflated with migration to PAWP waveform 0– P AP waveform; balloon inflated with migration to PAWP waveform Relationship between systemic and intracranial hemodynamics Case studies i n h emodynamic augmentation Diagnosis TCD waveform analysis Systemic and intracranial hemodynamic p arameters and oxygen calculatio Interpretation Treatment Interpretation Treatment Diagnosis TCD waveform/velocity analysis Systemic and intracranial hemodynamic p arameters and oxygen calculatio Interpretation Treatment Interpretation Treatment cm/s IABPW References 5 Practical Models of Cerebral Hemodynamics and W aveform Recognition Andrei V . Alexandrov The driving force Flow r esistance Pressure–flow r elationship of stenosis Practical models Flow velocity in stenosis Practical models Cerebral autoregulation Arterial bifurcations and collateral flow d istribution V asomotor r eactivity (VMR) Practical model How to r ead waveforms Practical model of an acute distal M1 MCA occlusion: How to Read Waveforms? Velocity Scale (cm/s) Background with no noise Signal Intensity (dB) Baseline Flow direction Time axis 1 second Specific waveforms Normal findings Increased pulsatility o f flow Envelope is a line that follows the waveform Figure 5.5 Increased r e sist Irregular heart rhythm Changes in the systolic flow acceleration Collateralization o f flow Aliasing and s ignal optimization Severe s tenosis, acute thrombosis and o cclusions Circulatory a rrest References Criteria for Interpretation 6 Diagnostic Criteria for Cerebrovascular Ultrasound Georgios T sivgoulis 1 , Marsha M. Neumyer 2 & Andrei V . Alexandrov 3 Normal extracranial and intracranial findings Laminar flow spectral broadening due to large gate or near wall placement ECA ICA temporal artery tapping bulb spectral narrowing Arterial wall pulsation Normal flow in the CCA Small gate < 3 mm Large gate 10 mm Normal flow in the ICA Normal flow in the E CA Normal flow in the V A Normal intracranial flow findings Carotid stenosis and p laque formation Residual lumen T otal v e ssel S 1 S 2 Carotid stenosis measured b y angiography Carotid stenosis measured b y ultrasound B-mode imaging o f carotid plaques Hyperechoic Healthy Control: IMT 1 mm in a stroke patient Hypoechoic Color-coded flow imaging o f carotid stenosis Angle-corrected Doppler velocimetry of the carotid stenosis Society o f R adiologists in U ltrasound multidisciplinary Consensus C V a lidation o f u ltrasound measurements o f carotid stenosis V a lidation o f u ltrasound criteria for d ifferent scanners Post-carotid endarterectomy assessment and carotid stents Grading bilateral carotid stenosis Left Right Non-affected side Affected side T andem carotid lesions Normal patency of a stent in the CCA PSV 90 cm/s EDV 12 cm/s Thrombosis of a stent in the prox ICA Thrombus Preserved IMT and vessel lumen ECA ICA V essel collapse chronic occlusion Carotid artery occlusion and dissection V e rtebral artery stenosis or occlusion Proximal BA vs collateral flow Reversed distal BA Left terminal VA Right terminal VA Intracranial s tenosis Middle cerebral a rtery (MCA) s tenosis Severe >70% Intracranial Stenoses Measurements: d – residual lumen n 1 – first choice n 2 – second n 3 – third lumen n 1 – first choice n 2 – second n 3 – third % Stenosis = (1-d/n)x100 T rial Targets: n 1 n 2 n 3 DSA stenosis 40% MCA s ub-total s tenosis or near-occlusion Anterior cerebral a rtery (ACA) T e rminal ICA a nd ICA s iphon Depth 72 mm MFV 130 cm/s Posterior cerebral a rtery (PCA) Basilar a rtery (BA) T e rminal vertebral artery (VA) Arterial stenosis and n ear-occlusions: s ummary Arterial vasospasm and hyperemia Criteria for vasospasm in other intracranial arteries Hyperemia L ACA MFV 188 PI 0.61 R ACA MFV 204 PI 0.4 L M1 MCA MFV 55 PI 0.7 R M1 MCA MFV 164 PI 0.8 ICA MFV 70 Lindegaard Ratio ICP ICP 20 ICP > 20 ICP = Diastol CPP < ICP CPP < ICP CPP