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2. Buckenham TM, Wright IA. Ultrasound of the extracranial vertebral artery. Br J Radiol.
2004;77(913):15–20.
3. Davis PC, Nilsen B, Braun IF, Hoffman JC.A prospective comparison of duplex sonography
vs angiography of the vertebral arteries. Am J Neuroradiol. 1986;7(6):1059–64.
4. Uacker R.Atlas of vascular anatomy. An angiographic approach. Philadelphia, PA: Lippincott
Williams; 1997.
5. Nicolau C, Gilabert R, Chamorro A, Vázquez F, Bargalló N, Brú C.Doppler sonography of the
intertransverse segment of the vertebral artery. J Ultrasound Med. 2000;19(1):47–53.
6. Trattnig S, Hübsch P, Schuster H, Pölzleitner D.Color-coded Doppler imaging of normal
vertebral arteries. Stroke. 1990;21(8):1222–5.
7. Purkayastha S, Sorond F.Transcranial Doppler ultrasound: technique and application. In:
Seminars in neurology, vol. 32, No. 4. NIH Public Access; 2012. p.411.
8. Bathala L, Mehndiratta MM, Sharma VK.Transcranial Doppler: technique and common ndings (Part 1). Ann Indian Acad Neurol. 2013;16(2):174.
9. Vergouwen MDI, Vermeulen M, van Gijn J, Rinkel GJE, Wijdicks EF, Muizelaar JP, et al.
Denition of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage as an outcome event in clinical trials and observational studies: proposal of a multidisciplinary research
group. Stroke. 2010;41:2391–5.
10. Kassell NF, Torner JC, Jane JA, etal. The international co-operative study on the timing of
aneurysm surgery. Part 1: overall management results. J Neurosurg. 1990;73(18).
11. Sloan MA, Burch CM, Wozniak MA, Rothman MI, Rigamonti D, Permutt T, etal. Transcranial
Doppler detection of vertebrobasilar vasospasm following subarachnoid hemorrhage. Stroke.
1994;25(11):2187–97.
12. Soustiel JF, Shik V, Shreiber R, Tavor Y, Goldsher D.Basilar vasospasm diagnosis: investigation of a modied “Lindegaard Index” based on imaging studies and blood velocity measurements of the basilar artery. Stroke. 2002;33(1):72–8.
13. Sviri GE, Ghodke B, Britz GW, Douville CM, Haynor DR, Mesiwala AH, etal. Transcranial
Doppler grading criteria for basilar artery vasospasm. Neurosurgery. 2006;59(2):360–6.
14. Sviri GE, Newell DW, Lewis DH, Douville C, Ghodke B, Chowdhary M, etal. Impact of basilar artery vasospasm on outcome in patients with severe cerebral vasospasm after aneurysmal
subarachnoid hemorrhage. Stroke. 2006;37(11):2738–43.
15. Gottesman RF, Sharma P, Robinson KA, Arnan M, Tsui M, Ladha K, etal. Clinical characteristics of symptomatic vertebral artery dissection. A systematic review. Neurol. 2012;18(5):245.
16. Schievink WI. Spontaneous dissection of the carotid and vertebral arteries. N Engl J Med.
2001;344(12):898–906.
17. Kim BM, Suh SH, Park SI, Shin YS, Chung EC, Lee MH, et al. Management and clinical
outcome of acute basilar artery dissection. Am J Neuroradiol. 2008;29(10):1937–41.
18. De Bray JM, Penisson-Besnier I, Dubas F, Emile J.Extracranial and intracranial vertebrobasilar dissections: diagnosis and prognosis. J Neurol Neurosurg Psychiatry. 1997;63(1):46–51.
19. Sturzenegger M, Mattle HP, Rivoir A, Rihs F, Schmid C.Ultrasound ndings in spontaneous
extracranial vertebral artery dissection. Stroke. 1993;24(12):1910–21.
20. Nebelsieck J, Sengelhoff C, Nassenstein I, Maintz D, Kuhlenbäumer G, Nabavi DG, et al.
Sensitivity of neurovascular ultrasound for the detection of spontaneous cervical artery dissection. J Clin Neurosci. 2009;16(1):79–82.
21. Vassileva E, Getsov P, Vavrek E, Daskalov M.Detection of basilar artery dissection by ultrasound. J Stroke Cerebrovasc Dis. 2015;24(5):e127–8.
22. Ruecker M, Furtner M, Knoach M, Werner P, Gotwald T, Chemelli A, et al. Basilar artery
dissection: series of 12 consecutive cases and review of the literature. Cerebrovasc Dis.
2010;30(3):267–76.
23. Dittrich R, Dziewas R, Ritter MA, Kloska SP, Bachmann R, Nassenstein I, et al. Negative
ultrasound ndings in patients with cervical artery dissection. J Neurol. 2006;253(4):424–33.
R. R. Gill et al.
27 Acute Neurologic Injury in the ICU: Role of Transcranial Doppler in Disorders…
24. Kasner SE, Chimowitz MI, Lynn MJ, Howlett-Smith H, Stern BJ, Hertzberg VS, et al.
Predictors of ischemic stroke in the territory of a symptomatic intracranial arterial stenosis.
Circulation. 2006;113(4):555–63.
25. Chimowitz MI, Lynn MJ, Derdeyn CP, Turan TN, Fiorella D, Lane BF, et al. Stenting
versus aggressive medical therapy for intracranial arterial stenosis. N Engl J Med.
2011;365(11):993–1003.
26. White H, Boden-Albala B, Wang C, Elkind MS, Rundek T, Wright CB, etal. Ischemic stroke
subtype incidence among whites, blacks, and Hispanics: the Northern Manhattan Study.
Circulation. 2005;111(10):1327–31.
27. Wong KS, Huang YN, Gao S, Lam WW, Chan YL, Kay R.Intracranial stenosis in Chinese
patients with acute stroke. Neurology. 1998;50(3):812–3.
28. Chimowitz MI, Lynn MJ, Howlett-Smith H, Stern BJ, Hertzberg VS, Frankel MR, etal.
Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis. N Engl J
Med. 2005;352(13):1305–16.
29. Feldmann E, Wilterdink JL, Kosinski A, Lynn M, Chimowitz MI, Saran J, etal. The stroke
outcomes and neuroimaging of intracranial atherosclerosis (SONIA) trial. Neurology.
2007;68(24):2099–106.
30. Zhao L, Barlinn K, Sharma VK, Tsivgoulis G, Cava LF, Vasdekis SN, etal. Velocity criteria for
intracranial stenosis revisited: an international multicenter study of transcranial Doppler and
digital subtraction angiography. Stroke. 2011;42(12):3429–34.
31. Vuković-Cvetković V.Microembolus detection by transcranial Doppler sonography: review of
the literature. Stroke Res Treat. 2012;2012
32. Srinivasan J, Newell DW, Sturzenegger M, Mayberg MR, Winn HR.Transcranial Doppler in
the evaluation of internal carotid artery dissection. Stroke. 1996;27(7):1226–30.
33. Droste DW, Junker K, Stögbauer F, Lowens S, Besselmann M, Braun B, etal. Clinically silent
circulating microemboli in 20 patients with carotid or vertebral artery dissection. Cerebrovasc
Dis. 2001;12(3):181–5.
34. Hwang J, Kim SJ, Hong JM, Bang OY, Chung CS, Lee KH, etal. Microembolic signals in acute
posterior circulation cerebral ischemia: sources and consequences. Stroke. 2012;43(3):747–52.
35. Del Sette M, Dinia L, Rizzi D, Sugo A, Albano B, Gandolfo C.Diagnosis of right-to-left shunt
with transcranial Doppler and vertebrobasilar recording. Stroke. 2007;38(8):2254–6.
36. Sharma AK, Bathala L, Batra A, Mehndiratta MM, Sharma VK.Transcranial Doppler: techniques and advanced applications: part 2. Ann Indian Acad Neurol. 2016;19(1):102.
37. Mojadidi MK, Roberts SC, Winoker JS, Romero J, Goodman-Meza D, Gevorgyan R, et al.
Accuracy of transcranial Doppler for the diagnosis of intracardiac right-to-left shunt: a bivariate meta-analysis of prospective studies. JACC Cardiovasc Imaging. 2014;7(3):236–50.
38. Guo YZ, Gao YS, Guo ZN, Niu PP, Yang Y, Xing YQ. Comparison of vertebral artery and
middle cerebral artery monitoring for right-to-left shunt detection by contrast-enhanced transcranial Doppler. Sci Rep. 2016;6:24932.
39. Osiro S, Zurada A, Gielecki J, Shoja MM, Tubbs RS, Loukas M.A review of subclavian steal
syndrome with clinical correlation. Med Sci Monit. 2012;18(5):RA57.
40. Mousa AY, Morkous R, Broce M, Yacoub M, Sticco A, Viradia R, et al. Validation of subclavian duplex velocity criteria to grade severity of subclavian artery stenosis. J Vasc Surg.
2017;65(6):1779–85.
41. Harper C, Cardullo PA, Weyman AK, Patterson RB. Transcranial Doppler ultrasonography of the basilar artery in patients with retrograde vertebral artery ow. J Vasc Surg.
2008;48(4):859–64.
42. Matta B, Czosnyka M.Chapter 7: Transcranial Doppler Ultrasonography in Anesthesia and
Neurosurgery. In: Cottrell JE, Patel P, editors. Neuroanesthesia. 6th ed. Philadelphia, PA:
Elsevier; 2017.
43. Aaslid R, Lindegaard KF, Sorteberg W, et al. Cerebral autoregulation in humans. Stroke.
1989;20:45.
479
480
44. Aaslid R, Newell DW, Stooss R, et al. Assessment of cerebral autoregulationmdynamics
from simultaneous arterial and venous transcranial Doppler recordings in humans. Stroke.
1991;22:1148.
45. Jiménez-Caballero PE, Segura T. Normal values of cerebral vasomotor reactivity using the
breath-holding test. Rev Neurol. 2006;43(10):598–602.
46. Park CW, Sturzenegger M, Douville CM, Aaslid R, Newell DW.Autoregulatory response and
CO2 reactivity of the basilar artery. Stroke. 2003;34(1):34–9.
47. Kimiagar I, Bass A, Rabey JM, Bornstein NM, Gur AY.Long-term follow-up of patients with
asymptomatic occlusion of the internal carotid artery with good and impaired cerebral vasomotor reactivity. Eur J Neurol. 2010;17(10):1285–90.
48. Park TH, Park SH, Yoon YC, Kwon OS. Vasomotor reactivity of the basilar artery in
patients with occlusive vascular diseases in the anterior circulation. J Korean Neurol Assoc.
2006;24(3):204–9.
49. Ract C, Le Moigno S, Bruder N, Vigue B. Transcranial Doppler ultrasound goal-directed
therapy for the early management of severe traumatic brain injury. Intensive Care Med.
2007;33:645–51.
50. Sloan MA, Alexandrov AV, Tegeler CH.Assessment: Transcranial Doppler ultrasonography:
report of the therapeutics and technology assessment subcommittee of the American Academy
of Neurology. Neurology. 2004;62:1468.
51. Purkayastha S, Sorond FA, Lyng S, Frantz J, Murphy MN, Hynan LS, etal. Impaired cerebral
vasoreactivity despite symptom resolution in sports-related concussion. J Neurotrauma. 2019;
52. Lele AV, Watanitanon A, Lakireddy V, Clark-Bell C, Moore A, Zimmerman JJ, etal. Prevalence,
evolution, and extent of impaired cerebral autoregulation in children hospitalized with complex mild traumatic brain injury. Pediatr Crit Care Med. 2018;
53. Vavilala MS, Farr CK, Watanitanon A, Clark-Bell BC, Chandee T, Moore A.Early changes in
cerebral autoregulation among youth hospitalized after sports-related traumatic brain injury.
Brain Inj. 2018;32(2):269–75.
54. Ziegler D, Cravens G, Poche G, Gandhi R, Tellez M.Use of transcranial Doppler in patients
with severe traumatic brain injuries. J Neurotrauma. 2017;34:121–7.
55. Ract C, Le Moigno S, Bruder N, Vigué B. Transcranial Doppler ultrasound goal-directed
therapy for the early management of severe traumatic brain injury. Intensive Care Med.
2007;33:645–51.
56. Bailey DM, Jones DW, Sinnott A, Brugniaux JV, New KJ, Hodson D, etal. Impaired cerebral
haemodynamic function associated with chronic traumatic brain injury in professional boxers.
Clin Sci. 2013;124:177–89.
57. da Costa L, van Niftrik CB, Crane D, Fierstra J, Bethune A.Temporal prole of cerebrovascular reactivity impairment, gray matter volumes, and persistent symptoms after mild traumatic
head injury. Front Neurol. 2016;7:70.
58. Albalawi T, Hamner JW, Lapointe M, Meehan WP III, Tan CO.The relationship between cerebral vasoreactivity and post-concussive symptom severity. J Neurotrauma. 2017;34:2700–5.
59. Bonow RH, Witt CE, Mosher BP, Mossa-Basha M, Vavilala MS, Rivara FP, etal. Transcranial
Doppler microemboli monitoring for stroke risk stratication in blunt cerebrovascular injury.
CCM. 2017;45(10):e1011–7.
60. Wijdicks EF, Varelas PN, Gronseth GS, Greer DM.Evidence-based guideline update: determining brain death in adults: report of the Quality Standards Subcommittee of the American
Academy of Neurology. Neurology. 2010;74(23):1911–8.
61. Hadani M, Bruk B, Ram Z, Knoller N, Spiegelmann R, Segal E.Application of transcranial doppler ultrasonography for the diagnosis of brain death. Intensive Care Med. 1999;25(8):822–8.
62. Sloan MA. Therapeutics and Technology Assessment Subcommittee of the American
Academy of Neurology: Assessment: transcranial Doppler ultrasonography: report of the
Therapeutics and Technology Assessment Subcommittee of the American Academy of
Neurology. Neurology. 2004;62:1468–81.
R. R. Gill et al.
27 Acute Neurologic Injury in the ICU: Role of Transcranial Doppler in Disorders…
63. Chang JJ, Tsivgoulis G, Katsanos AH, Malkoff MD, Alexandrov AV.Diagnostic accuracy of
transcranial Doppler for brain death conrmation: systematic review and meta-analysis. Am J
Neuroradiol. 2016;37(3):408–14.
64. Alexandrov AV, Tsivgoulis G, Rubiera M, Vadikolias K, Stamboulis E, Molina CA, etal. Enddiastolic velocity increase predicts recanalization and neurological improvement in patients
with ischemic stroke with proximal arterial occlusions receiving reperfusion therapies. Stroke.
2010;41(5):948–52.
65. Ducrocq X, Braun M, Debouverie M, Junges C, Hummer M, Vespignani H. Brain death
and transcranial Doppler: experience in 130 cases of brain dead patients. J Neurol Sci.
1998;160(1):41–6.
66. Blanco P, Abdo-Cuza A.Transcranial Doppler ultrasound in neurocritical care. J Ultrasound.
2018:1–6.
67. Kuo JR, Chen CF, Chio CC, Chang CH, Wang CC, Yang CM, etal. Time dependent validity
in the diagnosis of brain death using transcranial Doppler sonography. J Neurol Neurosurg
Psychiatry. 2006;77(5):646–9.
68. Baltgaile G.Cerebral circulatory arrest. In: Csiba L, Baracchini C, editors. Manual of neurosonology. Cambridge: Cambridge University Press; 2016. p.23–33.
69. Schreiber S.Cerebral circulatory arrest. In: Csiba L, Baracchini C, editors. Manual of neurosonology. Cambridge: Cambridge University Press; 2016. p.262–8.
481
Chapter 28
Intracerebral Venous System: Monitoring
by Transcranial Color-Coded Duplex
Sonography (TCCS)
DixonYang, MarialauraSimonetto, NellyCampo, DignaCabral,
andTatjanaRundek
Key Points
1. Cerebral venous drainage is divided into the deep and supercial venous drainage, with most reliably insonated vessels in the deep venous system.
2. Venous transcranial color-coded duplex sonography (vTCCS) imaging has good
reliability.
3. vTCCS has potential utility as a quick, bedside, complementary diagnostic and
monitoring tool.
4. Hemodynamic characteristics on vTCCS in cerebral venous sinus thrombosis
may complement the rst diagnostic line by CT or MR imaging.
5. vTCCS has clinical utility in AVM but also may be useful in ischemic stroke,
subarachnoid hemorrhage, and intracranial hypertension.
6. Further studies are needed to determine clinical value of vTCCS.
D. Yang
Department of Neurology, New York University Langone Health, New York, NY, USA
e-mail: Dixon.Yang@nyulangone.org
M. Simonetto · N. Campo · D. Cabral
Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
e-mail: NCampo@med.miami.edu
T. Rundek (
Evelyn F.McKnight Brain Institute, Department of Neurology, Miller School of Medicine,
University of Miami, Miami, FL, USA
e-mail: trundek@med.miami.edu
C. N. Rodríguez et al. (eds.), Neurosonology in Critical Care,
https://doi.org/10.1007/978-3-030-81419-9_28
*)
483© Springer Nature Switzerland AG 2022
484
D. Yang et al.
28.1 Introduction
Transcranial Doppler (TCD) and transcranial color-coded duplex sonography
(TCCS) have been widely used in examination and monitoring of extra- and intracranial arterial hemodynamics [1]. Less attention has been paid to the cerebral
venous counterpart due to early technical limitations and low clinical prevalence of
known cerebral venous disease. In adults, we were not able to formally study the
cerebral venous system using sonography until 1991 because of its technical limitations [2]. Although recent technical advances in neurosonology, venous transcranial
color-coded duplex sonography (vTCCS) does not currently belong to routine clinical examination modalities. However, vTCCS has potential utility as a quick, bedside, supplementary diagnostic and monitoring tool notably for cerebral vein and
sinus thrombosis (CVST) and arteriovenous malformations (AVM), and it has a
possible clinical value in ischemic stroke, subarachnoid hemorrhage (SAH), and
raised intracranial pressure (ICP) [3]. This chapter intends to review application and
clinical usefulness of vTCCS based on available evidence.
28.2 Cerebral Venous System: Anatomy
Relevant and reliably insonated cerebral venous anatomy to sonography consists
of the deep cerebral venous drainage, contributories of the cavernous sinus, posterior fossa sinuses, inferior petrosal sinus, and vertebral plexus [4]. Beginning anteriorly, blood drained from frontal brain regions into anterior cerebral veins forms
the deep middle cerebral vein (DMCV), which is often located adjacent to the
middle cerebral artery. The DMCV drains into the basal vein (BV), which runs a
course distally to the follow in the P2 segment of the posterior cerebral artery
around the midbrain. Bilateral BVs (also known as the veins of Rosenthal) join
midline to form the unpaired great cerebral vein (GCV) or the vein of Galen
behind the pineal gland. Along with the inferior sagittal sinus (ISS), the GCV
drains mostly into the unpaired straight sinus (SRS) located at the apex of the
cerebellum tentorium [5].
The SRS ows to the conuens sinuum (COS), where it meets supercial cerebral venous drainage that is functionally separated from deep cerebral venous vasculature by a venous watershed. Notably of the supercial system, the superior
sagittal sinus (SSS) drains into the COS and then bifurcates into the transverse
sinuses (TS), which dives underneath the occipital bone to eventually forms the
sigmoid sinus and drains into the internal jugular vein. It should be noted that the
low ow velocities, unfavorable insonation windows, and frequent anatomic variations of the SSS, COS, and TS make them less detectable vessels on vTUS [6, 7]
(Fig.28.1).
Superior
ein
sinus
28 Intracerebral Venous System: Monitoring by Transcranial Color-Coded Duplex…
485
Fig. 28.1 Intracerebral
venous system anatomy
sagittal sinus
Occipital
sinus
Inferior
sagittal sinus
Straight
sinus
Sigmoid
sinus
Internal
cerebral veins
Basal vein
of Rosenthal
Great
cerebral vein
(Galen vein)
Internal
jugular v
Transverse
28.3 vTCCS: Ultrasound Investigation Technique
Intracranial venous examination with ultrasound (TCCS) generally begins with
insonation through the temporal window to identify the mesencephalon as a landmark.
From there, the deep middle cerebral vein is found adjacent to the middle cerebral artery,
with venous ow toward the center of the brain, away from the probe. Downward angulation can visualize the sphenoid bone and superior petrosal sinus with ow away from
the probe, draining into the cavernous sinus that usually cannot be insonated. Upward
angulation from the mesencephalon can visualize the basal vein of Rosenthal (Fig.28.2),
which is slightly cranial from the P2 segment of the posterior cerebral artery.
Brightness mode (B-mode) increases depth so that contralateral structures can be
insonated. The great cerebral vein (Fig.28.3) can be found behind the echogenic
pineal gland and third ventricle. The straight sinus (Fig.28.4) can be located after
upward rotation of the transducer to visualize the echogenic cerebellar tentorium. It
drains away from the transducer toward the conuens sinuum. The contralateral
transverse sinus (Fig.28.5) can be seen with downward angulation. Transforaminal
examination will reveal the vertebral venous plexus and the inferior petrosal sinus
near the basilar artery, with venous ows directed toward the transducer.
There are no consensus guidelines regarding vTCCS examination, but there are
several validated TCCS and TCD protocols that use this general approach [8].
TCCS is often preferred because it can display vascular anatomy in relation to brain
parenchyma and not only ow velocities and ow direction as in non-imaging
TCD.Further signal improvement can be achieved by intravenous administration of
echo-contrast, which is not commonly used in most TCCS or TCD protocols.
Established normative data are presented in Table28.1.
486
Fig. 28.2 Basal vein of Rosenthal
D. Yang et al.
Fig. 28.3 Great Cerebral vein (Galen)
28 Intracerebral Venous System: Monitoring by Transcranial Color-Coded Duplex…
Fig. 28.4 Straight sinus
487
Fig. 28.5 Transverse sinus
488
Table 28.1 Venous ow velocities of healthy adults using TCCS without angle-correction
Vessel Peak systolic ow (cm/s) End diastolic ow (cm/s) Visualization (%)
DMCV 8.5±2.9
8.7±2.9
8.6±1.9
BV 12.4±4.0
12.2±3.8
11.9±2.9
SRS 13.1±5.1
12.2±3.8
11.6±2.3
GCV 10.6±3.7
11.9±3.6
10.2±1.8
TS 4.9±6.7
14.0±5.9
16.4±4.4
SSS/CON 10.6±3.6
9.8±3.6
12.2±4.1
Data within each cell is listed in order from Stolz [8–10]
Percent visualization of veins is presented in range across the three studies
5.7±1.9
5.8±1.9
5.9±1.4
8.9±3.0
8.6±3.7
7.2±1.8
9.4±4.0
8.6±3.7
7.2±1.8
7.5±2.8
7.7±2.8
7.4±1.5
10.4±5.3
9.7±4.8
11.8±3.7
6.7±2.6
6.1±2.5
8.7±3.3
D. Yang et al.
76-91
89-95
71-83
89-98
67-69
52-58
28.4 CVST: Venous Ultrasound Findings
Urgent neuroimaging using magnetic resonance imaging (MRI) with venography or
computed tomography (CT) with venography are the rst choice diagnostic tools
for acute CVST, with digital subtraction angiography as the gold standard [11].
Normal sonographic ndings in vTCCS cannot positively rule out CVST even if
contrast enhancers are used; however, vTCCS may serve as a complementary tool
to MRI or CT [3]. In 1994, increased venous ow signal in bilateral DMCVs was
rst reported in SSS thrombosis, which normalized after anticoagulant therapy [12].
Smaller reports have supported changed venous hemodynamics in SSS thrombosis
though in different vessels [13, 14]. Given the absence of valves in the cerebral
venous drainage, intracranial veins may serve as collaterals and their ow may even
reverse [5]. Four sonographic ow characteristics of CVST have been described,
broadly classied as one direct criterion and three indirect criteria.
The direct criterion involves missing venous ow signals that would theoretically suggest cut-off ow from thrombosis. However, vTCCS cannot reliably distinguish between frequently encountered anatomical variations and occlusive clot.
Even with echo-contrast TCCS, occluded ow was either aplastic TS or complete
TS occlusion after MRI conrmation, while residual sonographic signals were
either hypoplastic vessel or non-occluded TS thrombosis. Examination with vTCCS
in one study missed one case of complete TS occlusion due to false-positive signal
from a dural stula [15]. Clinically, this direct criterion’s sensitivity and specicity
are too low for practical use.