Transcranial Doppler (Basic Step) Dae-il Chang, M.D., Sung Sang Yoon, M.D. Department of Neurology, College of Medicine, Kyunghee university

Transcription

1 Transcranial Doppler (Basic Step) Dae-il Chang, M.D., Sung Sang Yoon, M.D. Department of Neurology, College of Medicine, Kyunghee university

2 Principles of Doppler Ultrasonography Major target Speed & direction of red cells in vessel Doppler equation F(MHz) = Reflector speed(m/sec) = 2 x reflector speed(m/sec) x transmitted frequency(mhz) x cos propagation speed(m/sec) F(MHz) x propagation speed(m/sec) 2 x transmitted frequency(mhz) x cos

3 3 Layer structure Structure of Skull Inner table Diploe cancellous bone Compact ivory bone Outer table Effect to ultrasound penetration Cancellous bone attenuation, scatter (major) Compact ivory bone refraction (minor)

4 Identify the Insonated Artery 1. The window 2. The orientation of the transducer 3. The direction of flow, toward or away 4. The sample volume depth 5. The contour of the waveform

5 Identify the Insonated Artery Vessel Window Probe orientation Depth (mm) Flow direction Waveform OA orbital slightly medial toward high resistance ICA(siphon) orbital slightly medial bidirectional low resistance MCA temporal En face toward low resistance ACA PCA temporal temporal anteriorly posteriorly away toward low resistance low resistance VA suboccipital superiorly away low resistance BA suboccipital superiorly away low resistance

6 Identify the Insonated Artery Vessel Carotid vibration Ipsilat. carotid compression Contralat. carotid compression OA ICA(siphon) MCA Responses Reduced velocities No change ACA PCA Responses Does not respond Flow reversal Increased velocity/no change Increased velocity No change VA BA - - -

7 Orbital window Ipsilateral OA, ICA Both ACA, contralateral MCA Temporal bone window Anterior, middle, posterior temporal window Ipsilateral MCA, ACA, PCA Terminal ICA, BA, Contralateral ACA, MCA, PComA Foramen magnum window Both VA, BA Acoustic Windows

8 Orbital Window Ipsilateral OA, ICA Both ACA, contralateral MCA Depth 40~50 (OA) Depth 70 (ICA) superior Depth 67 (ICA) middle Depth 75 (ICA) inferior

9 Ipsilateral OA Orbital Window

10 Hemodynamic Signs in ICA Stenosis % mm s Hemodynamic Sign Direct doppler frequency rises OPG becomes abnormal Supraorbital artery reverses (200~250 cm/s) Anterior cerebral fills from opposite side Occipital artery reaches internal occipital protuberance before opercular vessels fill out Supratrochlear artery reverses (400 cm/s) Direct doppler frequencies fall

11 Orbital Window Ipsilateral ICA (Siphon) (1) (1) (2) (2)

12 Temporal Bone Window Ipsilateral MCA, ACA, PCA Terminal ICA, BA, Contralateral ACA, MCA, PComA Depth 63 (MCA) Depth 67 (ACA & MCA) Depth 81 (ACA) Depth 63 (PCA)

13 Ipsilateral MCA Temporal Window

14 Ipsilateral ACA Temporal Window

15 Ipsilateral PCA Temporal Window (2) (1) Toward flow (1) (2) Away flow

16 Temporal Window Terminal ICA (1), BA (2), Contralateral ACA, MCA (3), PComA (4) (1) (2) (3) (4)

17 Foramen Magnum Window Both VA, BA Depth 66 (VA) Depth 74 (VA & PICA) Depth 84 (BA) Depth 93 (BA)

18 Foramen Magnum Window VA & BA (1) (2) (2) (1)

19 TCD Indexes Peak systolic velocity (PSV) End-diastolic velocity (EDV) Mean flow velocity (MV) Pulsatility index (PI) Pulsatile transmission index (PTI) Resistance index (RI) Flow acceleration (FA) Delta middle cerebral artery (D-MCA) Hemispheric index (HI) Arterial velocities ratio (AVR)

20 Reference Values in Korea 1. GB Ahn, CS Chi, CS Chung. Recording of cerebral blood flow velocity using transcranial Doppler ultrasound in normal subjects. J Korean Neurol Asso 1991;9: Kim GW, Sohn YH, Lee SM, Lee JH, Kim DS, Kim JY et al. The reference values and influencing factors of TCD measurements in 200 normal Korean adults. J Korean Neurol Asso 1995;13: SJ Cho, CS Chung, KH Lee. Reference values of transcranial Doppler ultrasonography measurements of healthy adults with normal MRI and MRA findings. J Korean Neurol Asso 1998;16:

21 Flow Velocities Peak systolic End-diastolic Mean = PV - 2EDV 3

22 Normal Reference Values Flow Velocities Mean velocity Systolic velocity Diastolic velocity Men Women Men Women Men Women MCA ACA PCA C C OA VA Prox BA Dist BA ICA ECA CCA

23 Normal Reference Values Flow Velocities 30~49 years (n=29) 50~59 years (n=57) 60~69 years (n=20) MV SV MV SV MV SV MCA ACA PCA C C OA VA Prox BA Dist BA ICA ECA CCA

24 Pulsatility Index PI = Peak systolic velocity End-diastolic velocity Mean flow velocity Reflection of distal vascular resistance High vascular resistance pattern PI, extracranial vessels Low vascular resistance pattern PI, intracranial vessels

25 Pulsatility Transmission Index Pulsatility index (study vessel) PTI = x 100 % Pulsatility index (reference vessel) Consideration systemic factor HR, BP, vascular compliance, PaCO 2 etc. Reference vessel normal (?)

26 Resistance Index RI = Peak systolic velocity - end-diastolic velocity Peak systolic velocity Reflection of distal vascular resistance

27 Normal Reference Values of PI & RI 30~49 years (n=34) 50~59 years (n=72) 60~69 years (n=25) PI RI PI RI PI RI MCA ACA PCA C C OA VA Prox BA Dist BA ICA ECA CCA

28 Flow Acceleration FA = Peak systolic velocity - end-diastolic velocity Time differential Systolic upstroke pattern of waveform Reflection of proximal vascular disease

29 Delta Middle Cerebral Artery D-MCA = MCA PV (ipsilateral to ICA stenosis) MCA PV (contralateral to ICA stenosis) Reflection of ICA stenosis Left-Right ratios of mean & systolic velocity Lt-Rt ratios of SV Lt-Rt ratios of MV MCA (0.65~1.43), 0.66 ~ (0.66~1.40), 0.68 ~ 1.81 ACA (0.52~1.50), 0.61 ~ (0.58~1.48), 0.62 ~ 1.76 PCA (0.57~1.51), 0.56 ~ (0.58~1.48), 0.52 ~ 2.00

30 Hemispheric Index HI = Mean velocity of middle cerebral artery Mean velocity of internal carotid artery Differentiation vasospasm vs hyperemia Similar MV BA / MV VA Criteria HI < 55 = 4, >55 = 2.5 MV BA / MV VA < 55 = 3, > 55 = 2.5

31 Arterial Velocities Ratio ACA, MCA VR = PCA, MCA VR = Velocity of ACA Velocity of MCA Velocity of PCA Velocity of MCA ACAVR = Velocity of ACA (ipsilateral to MCA stenosis) Velocity of ACA (contralateral to MCA stenosis) Reflection of MCA stenosis

32 Reference Values of ACA-MCAVR, PCA-MCAVR, HI AMVR mean SD (Range) (0.53~1.27) actual range 0.49 ~ 1.72 PMVR mean SD (Range) (0.29~0.86) actual range 0.27 ~ 1.81 HI mean SD (Range) (0.97~2.96) actual range 1.06 ~ 5.05