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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5783_Библиотеки_им_академика_М_И_Перельмана.pdf
7 Transcranial Doppler (TCD) and Trancranial Color-Coded Duplex Sonography…
121
a
Fig. 7.4 (a) Diencephalic plane by TCCS through of transtemporal acoustic window: (1) thalamus, (2) pineal gland, (yellow arrow) third ventricle and (green arrow) contralateral skull; (b) brain
MRI: (1) thalamus, (yellow arrow) third ventricle, (dotted line) ultrasound beam through transtemporal window and (green arrow) contralateral skull. (Author: Camilo N.Rodríguez)
b
2. Thalamus.
[Two hypoechoic structures next to third ventricle]
3. Pineal Gland.
[Posterior hyperechoic structure] [3, 4]
4. Contralateral Skull Bone.
[Posterior hyperechoic structure]
B. Vascular structures identied by TCCS.
• TCCS: Doppler mode.
1. Middle cerebral artery (M2 segment).
2. Middle cerebral artery (M3 segment).
7.2.1.3 Ventricular Plane (Cella Media)
This plane is obtained by a slight displacement of the transducer toward the cephalic
10° from the diencephalic plane through the transtemporal window.
A. Brain parenchymal structures identied by TCCS.
• TCCS: B-mode.
1. Anterior horns of lateral ventricles (Fig.7.5).
[Two anterior hypoechoic structures]
B. Vascular structures identied by TCCS.
• TCCS: Doppler mode.
1. Middle cerebral artery (M3 segment).
122
C. N. Rodríguez and R. Splittgerber
a
Fig. 7.5 (a) Ventricular plane by TCCS through transtemporal acoustic window: (1) anterior
horns of lateral ventricles, (arrow) contralateral skull. (b) Brain MRI: (1) anterior horns of lateral
ventricles and ultrasound beam (dotted line). (Author: Camilo N Rodríguez)
b
7.2.1.4 Upper Pons Plane
This plane is obtained by a caudal projection of the transducer toward the base of
the skull from the mesencephalic plane [10].
A. Skull and brain parenchyma structures identied by TCCS.
• TCCS: B-mode.
1. Sphenoid bone (anterior).
2. Cerebellum (posterior).
B. Vascular structures identied by TCCS.
• TCCS: Doppler mode.
1. Internal carotid artery (carotid siphon).
2. Ophthalmic artery.
7.2.1.5 Lower Pons Plane
This plane is obtained by a caudal projection of the transducer toward the base of
the skull from the superior pontine plane [10].
A. Skull structures identied by TCCS.
• TCCS: B-mode.
1. Sphenoid bone (anterior).
B. Vascular structures identied by TCCS.
• TCCS: Doppler mode.
1. Internal carotid artery (C6 segment).
7 Transcranial Doppler (TCD) and Trancranial Color-Coded Duplex Sonography…
123
a
Fig. 7.6 (a) Scheme (coronal cut): anatomy of C1 segment of ICA and MCA; (1) C1 segment of
internal carotid artery (ICA) and (2) anterior horns of lateral ventricle. (b) TCCS B-mode: anterior
coronal plane by transtemporal window; (1, 2) anterior horns of lateral ventricle, (3) transtemporal
acoustic beam, (4) contralateral skull bone, and (A, B) (yellow arrows) carotid groove of the sphenoid bone (C1 segment of ICA). (Author: Camilo N.Rodríguez)
b
7.2.1.6 Coronal Plane (Anterior) (Fig.7.6)
From the transtemporal window, at the level of the mesencephalic plane, a 90° rotation of the probe is performed by the operator [10].
A. Brain parenchymal structures identied by TCCS.
• TCCS: B-mode.
1. Anterior horns of lateral ventricles.
2. Midline (hyperechoic).
B. Vascular structures identied by TCCS.
• TCCS: Doppler mode.
1. Carotid sulcus (Carotid groove of the sphenoid bone: horizontal hyper-
echoic lines on each side of midline).
2. M1 segment (MCA).
7.2.2 Transforaminal Window
This window allows to localize the insonation of the basilar artery and the intracranial portion of the vertebral arteries (V4 segments) by projecting the ultrasound
beam between the atlas (C1) and the base of the skull [11].
A. Skull structure identied by TCCS (Fig.7.7).
• TCCS: B-mode.
1. Foramen magnum (occipital foramen) [3, 7–9, 12] (Hypoechoic).
124
C. N. Rodríguez and R. Splittgerber
a
b
cd
Fig. 7.7 (a) Transforaminal acoustic window by TCCS (B-Mode): (1) foramen magnum. (b)
Transforaminal acoustic window by TCCS (duplex): (1) vertebral artery (blue), (2) basilar artery
(blue). (c) Scheme: anatomy of occipital bone;(1) occipital bone, (2) occipital condyle, and (3)
foramen magnum. (d) Scheme of insonation through transforaminal window by TCCS: (1) basilar
artery, (2) and (3) vertebral arteries, and (4) foramen magnum. (arrow) It highlights that the ow
away from transducer. (Blue color). (Author: Camilo N.Rodríguez)
B. Vascular structures identied by TCCS (Fig.7.7).
• TCCS: Doppler mode.
1. Vertebral arteries (VA) (Intracranial portion– V4).
2. Basilar artery (BA).
7.2.3 Neuroorbital Acoustic Window (Fig.7.8)
By placing the probe on the eyeball (upper eyelid), either on an axial or sagittal
axis, the ultrasound beam projection is very useful to explore neurovascular-orbital
structures [10, 11].
ab
7 Transcranial Doppler (TCD) and Trancranial Color-Coded Duplex Sonography…
Fig. 7.8 (a) Scheme: axial cut through the orbit; (1) zygoma, (2) ethmoidal sinus, (3) zygomatic
bone, (4) orbital sheet of ethmoidal bone, (5) frontal process of maxillary bone, and (6) middle
fossa. (b) Scheme: superior view of right orbit; (1) optic chiasm, (2) internal carotid artery, (3)
optic nerve, (4) ophthalmic artery, (5) central retinal artery, (6) eyeball, (7) cribriform sheet of
ethmoid bone, and (8) lacrimal gland. (Author: Camilo N.Rodríguez)
125
A. Structures of the orbit identied by TCCS.
• TCCS: B-mode.
• Anterior.
1. Eyeball (hypoechogenic).
2. Pupil.
• Posterior.
1. Papilla (Normal diameter: 1–1.5mm).
2. Optic nerve.
3. Optic nerve sheath diameter (ONSD) (NV: 4–5mm).
B. Vascular structures of the orbit identied by TCCS.
• TCCS: Doppler mode.
1. Central retinal artery (CRA).
2. Ophthalmic artery (OA).
126
ab
C. N. Rodríguez and R. Splittgerber
7.2.4 Submandibular Acoustic Window (Figs.7.9 and7.10)
The submandibular acoustic insonation window is used to study neck vessels (internal carotid artery (ICA)). It is also an alternative access to the vessels of the posterior cerebral circulation (vertebral arteries (VA) and basilar artery (BA)) during
transcranial color-coded duplex sonography (TCCS) in the ICU patient [14].
A. Cerebrovascular structures.
1. Carotid system (Fig.7.10).
(a) Common carotid artery (CCC).
(b) Internal carotid artery.
(c) External carotid artery.
2. Vertebral arteries.
3. Basilar artery.
Fig. 7.9 (a) Scheme: supercial anatomy of neck: (1) angle of the mandible,(2) sternocleidomastoid muscle, (3) thyroid cartilage, and (4) anterior (carotid) triangle of neck. (b) Scheme: anatomy
of anterior (carotid) triangle of neck: (1) sternocleidomastoid muscle, (2) internal jugular vein, (3)
internal carotid artery, (4) external carotid artery, (5) common carotid artery, (6) submandibular
gland, (7) parotid gland, (8) thyroid cartilage, (9) hyoid bone, (10) sternohyoid muscle, (11) mylohyoid muscle, (12) anterior belly of the digastric muscle, (13) external jugular vein, and (14) clavicular portion of sternocleidomastoid muscle. (Author: Camilo N.Rodríguez)
7 Transcranial Doppler (TCD) and Trancranial Color-Coded Duplex Sonography…
127
a
Fig. 7.10 (a) Submandibular acoustic window by TCCS: (1) external carotid artery (blue), (2)
internal carotid artery (blue), and (3) common carotid artery (blue) (primitive). (b) Scheme of
carotid system insonation by TCCS: (3) external carotid artery (blue), (2) internal carotid artery
(blue), and (1) common carotid artery (blue). Arrow: indicates ow away from transducer. (Author:
Camilo N.Rodríguez)
b
7.3 Arteries oftheBrain: Anatomy andUltrasound
The goal of transcranial Doppler (TCD) combined with the transcranial color-coded
duplex sonography (TCCS) is an integral approach to measure the velocities of the
cerebral blood ow (CBF) in the circle of Willis.
A deep understanding of cerebral vascular anatomy and its common anatomical
variations is an absolute prerequisite to interpret TCD/TCCS.
7.3.1 Cerebral Circulation: Circle ofWillis (Fig.7.11)
The circle of Willis is an anastomotic vascular structure located at the base of the
brain (around the interpeduncular cistern) constituted by two large arterial systems:
The anterior circulation system is supplied by both internal carotid arteries and the
posterior circulation system, which consists of the vertebrobasilar arterial system.
This vascular structure is often asymmetric with absent and/or hypoplastic vessels (51%) on its conformation and anatomical presentation. Between 20% and 49%
of the population have anatomical variations in the circle of Willis [15, 18].
128
C. N. Rodríguez and R. Splittgerber
a
Fig. 7.11 (a) Scheme of anatomy of the circle of Willis: (1) internal carotid artery; (2) middle
cerebral artery M1–M2 segments; (3) anterior communicating artery; (4) anterior cerebral artery;
(5) posterior communicating artery; (6) posterior cerebral artery; (7) vertebral artery; (8) posterior
inferior cerebellar artery; (9) basilar artery. (b) Circle of Willis by TCCS through transtemporal
acoustic window: (1) mesencephalon, (MCA-M1) ipsilateral M1 segment of middle cerebral
artery, (PCA-P1) P1 segment of posterior cerebral artery, (ACA-A1) A1 segment of anterior cerebral artery, and (MCAc-M1) contralateral M1 segment of MCA. (Author: Camilo N.Rodríguez)
b
7.3.1.1 Structure ofCircle ofWillis
A. Anterior circulation system (carotid system).
A.1 Internal carotid artery.
A.2 Middle cerebral artery.
A.3 Anterior cerebral artery.
A.4 Anterior communicating artery (AComA).
A.5 Posterior communicating artery (PComA)
B. Posterior circulation system (vertebrobasilar system).
B.1 Vertebral arteries.
B.2 Basilar artery.
B.3 Posterior cerebral artery (PCA).
7.3.1.2 Anterior Circulation
Carotid System
The carotid arteries originate bilaterally at the base of the neck from the subclavian
artery. Both common carotid arteries may differ in length and origin. Right CCA is
branched from the brachiocephalic trunk, and the left CCA branches directly from
the aortic arch. The CCA, in the carotid triangle of neck, will then divide into the
ICA and the ECA [15].
7 Transcranial Doppler (TCD) and Trancranial Color-Coded Duplex Sonography…
Fig. 7.12 Scheme of
anatomy of internal carotid
artery: (C7) cervical
portion, (C6) petrosal
portion, (C3-C4-C5)
cavernous portion where
C3 (carotid syphon),
(C1-C2) cerebral portion,
(3) ophthalmic artery, (4)
posterior communicating
artery, (5) anterior
choroidal artery, (6)
anterior cerebral artery, (7)
middle cerebral artery, 8)
temporal bone, and (9)
petrous portion of the
temporal bone. (Author:
Camilo N.Rodríguez)
129
Internal Carotid Artery (Fig.7.12)
This artery supplies most of the cerebral hemispheres, the eye, and other accessory organs.
• Diameter: 4.5mm.
• Length: 250mm.
The ICA is divided into four portions (caudal to cephalic) and seven subsegmentations [16] (Fig.7.12):
(a) Cervical portion (C7 Segment).
(b) Petrosal portion (C6 Segment).
(c) Cavernous portion.
• C3 segment (carotid syphon).
– Can be monitored by TCD and TCCS through transorbital and transtem-
poral acoustic windows [24].
130
TCD: Depth 55–70mm (transorbital window).
TCCS: Transtemporal window (axial approach: superior pontine plane
and anterior coronal plane approach)
• C4 segment.
• C5 segment.
(d) Cerebral portion.
• C1 segment.
Before terminal bifurcation can be measured:
TCCS: Anterior coronal plane through transtemporal window.
Duplex: Ipsilateral C1 segment: red color
• C1 segment: Terminal branches.
1. Anterior cerebral artery.
2. Middle cerebral artery.
• C2 segment (caudal to cephalic).
1. Ophthalmic artery (OA).
TCD: Depth 40–50mm (transorbital window).
TCCS: Transtemporal acoustic window (superior pontine plane) and
transorbital acoustic window
2. Posterior communicating artery.
3. Anterior choroidal artery (AChA).
C. N. Rodríguez and R. Splittgerber
Other Anatomical Classication
The ICA is divided into four segments (caudal to cephalic): [17].
1. C1 segment (cervical).
2. C2 segment (petrosal).
3. C3 segment (cavernous).
4. C4 segment (supraclinoid).
• Ophthalmic artery.
• Posterior communicating artery.
• Anterior choroidal artery.
Anterior Cerebral Artery
It is the smallest branch of the two terminals of the internal carotid artery. It branches
at the inner end of the Sylvian ssure [19, 24].
The anterior cerebral artery is subdivided into ve segments:
(a) Precommunicating segment.
A1 Segment
• Average diameter: 1.6–2.5mm.