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R. Jain et al.
10.7.2.4 Pedal Access [3]
Principle It is reserved for cases of failed antegrade recana-
lization. It is presumed that distal plaque is softer, which
allows easy passage into lumen, then subintimal passage
with rm proximal plaque. The tibial artery can be used for
retrograde lower extremity procedures but can only accommodate small catheters (3–4 French) [3].
Site Selection and Technique Various techniques to localize vessels include uoroscopic guidance in heavily calcied
vessels, roadmapping by antegrade angiography from the
femoral access and ultrasound guidance. The position of foot
should be plantar exion for dorsalis pedis and anterior tibial
artery, eversion and dorsiexion for posterior tibial artery
and inversion for peroneal artery. The choice of distal vessel
is based on arterial diameter and the presence of a relatively
normal artery [3]. In our setting, it is commonly done using
ultrasound with the target vessel xed against the underlying
bone. It is done under minimal local anesthesia (1–2ml) as
the vessel is supercial and small in size. Micropuncture
needle is used to access the vessel. Cocktail mixture (heparin, nitroglycerine, and occasionally calcium channel blockers) should be given to prevent thrombosis and spasm of
small vessels [3].
Complications Thrombosis and spasm of access vessels
have been reported [3].
10.7.2.5 Others
Popliteal Artery
It is reserved for cases where contralateral retrograde femoral access and antegrade femoral access fail with few indications like embolization of foot lesions and angioplasty of
stenosis involving supercial femoral artery. The patient is
placed in a prone position, and the artery is assessed with a
micropuncture needle under ultrasound guidance, either in
antegrade or retrograde direction. The minimal popliteal
artery diameter required is ~4 mm. The limitations of this
access are the exclusion of a combined approach (as the
patient is lying prone), inconvenient position, and increased
risk of access site complications (especially arteriovenous
stula).
Translumbar Aorta
Translumbar aorta is an uncommon access route. Aorta is
large with constant position, and puncture is guided using
bony landmark under uoroscopy. The patient should remain
in prone position. Anticoagulation is contraindicated, and
selective angiography is more challenging. A few contraindications to this access are coagulopathy, uncontrolled hypertension, suprarenal aortic aneurysm, severe scoliosis, and
dense atherocalcic changes. TLA puncture can be high
(inferior endplate of T12 vertebral body, more common) or
low (inferior endplate of L3 vertebral body). The main complication is retroperitoneal hematoma; small psoas hematoma is usually seen in all patients, and hemothorax is a very
rare complication.
10.8 Post-procedure Care
The most common technique and the current gold standard
to achieve hemostasis is manual compression [4].
10.8.1 Manual Compression
The tips of the second, third, and fourth ngers are placed
before removing the catheter with the third nger approximately over the arterial puncture site (Fig.10.6). After letting
Fig. 10.6 Manual
compression technique. (a)
Three ngers are placed over
common femoral artery
before the removal of the
sheath. (b) Compression is
applied over arterial puncture
site after letting some blood
spurt out
a
b
10 Vascular Access
99
Table 10.5 Vascular closure devices
Type Mechanism Examples
Active closure
devices
Compression assist
devices
Topical hemostasis
devices
Directly close the arteriotomy
site
Collagen based
Suture based
Staple or clip based
Provide sustained pressure at
puncture site
Mechanical clamps
Adjunct to manual
compression
Procoagulant pads
Water-soluble sealants
Vasoseal
Angioseal
Perclose
StarClose
Axera
Syvek patch
a small amount of back bleed, occlusive pressure is applied
for 1–2min, followed by a gradual reduction in pressure over
15 min. The ngers are gently removed, and the site is
watched for bleeding. If bleeding persists, the same process
is repeated. The vitals should be monitored, sometimes,
patients may have a vasovagal response. Distal pulse should
also be checked during compression. Patients with deranged
coagulation parameters, on systemic anticoagulation, high
systolic blood pressure (>160mm Hg), and heavily calcied
vessels have an increased risk of bleeding. After manual
compression, the leg should be immobilized for 6–8h.
Table 10.6 Predisposing factors for access site complications
Patient related Procedure related
Advanced age
Female gender
Coagulopathy
Obesity
Comorbidities—Hypertension,
diabetes, renal failure
Lower extremity vascular disease
Hostile groin (scarring, graft
material)
High division of femoral artery
Non-cooperative patient
Faulty puncture
techniques—Multiple
punctures, high above
inguinal ligament/below in
SFA/DFA, lack of pulse
assessment
Sheath/catheter size (>8Fr)
Duration of the procedure
Procedure within 24h of
thrombolytic therapy
Stent implantation
Higher drug doses
10.10 Venous Access
Similar to arterial access, there are few prerequisites prior
to venous access, which includes patency of the vessel,
large enough to accommodate catheters and diagnostic
devices, and healthy overlying skin. But as veins cannot be
palpated, image guidance technique is useful for venous
punctures.
Venous puncture sites include common femoral vein
(most common), internal jugular vein, subclavian vein, upper
extremity veins, and IVC.
10.8.2 Vascular Closure Devices (VCD)
These are available mechanical devices to achieve hemostasis following arterial access. It can be broadly categorized as
described in Table10.5 [4].
Manual compression and VCD are associated with some
of the complications (manual compression—0–3%, VCD
use—0–7%), including sustained bleeding, arterial thrombosis, hematoma, pseudoaneurysm formation, and arteriovenous stula [4]. Additionally, a new subset of complications
with VCD use includes deployment failure, embolization of
device material, and infection [4].
10.9 Complications [5–8]
There are several predisposing factors for access site complications. These are shown in Table10.6.
The complications related to access site are tabulated in
Table10.7.
10.10.1 Common Femoral Vein
Site Selection Common femoral vein (CFV) should be
punctured over the femoral head (preferably lower third),
above the saphenofemoral junction.
Principles and Technique Similar to CFA, this segment is
large and constant, and the vein is contained within the femoral sheath fascia. It can be accessed blind (medial to CFA)
or preferably using ultrasound guidance. After localizing, the
skin is anesthetized. For a single-wall puncture, hollow needle without stylet is used. Suction is applied while advancing
the needle as blood is aspirated when the needle enters the
vessel. It can also be done with a trocar needle under ultrasound guidance where the stylet is removed when needle tip
is seen within the vessel lumen. In case blood is not seen, the
needle is slowly withdrawn while maintaining suction. In
case of failed attempt, it is repeated with slightly varying
angle; however, lateral trajectory is avoided to prevent arte-
100
Table 10.7 Complications of arterial access
Complication Incidence Salient features Treatment and precaution
Hematoma <1% Probable cause
–multiple punctures
–posterior wall puncture
–rm compression
–mark boundaries (early recognition of
expanding hematoma in case of active bleeding)
–hypertension
–inadequate compression
Diagnosis
–swelling and bruising around access site
Retroperitoneal
bleed
<1%
But potentially
fatal
Probable cause
High puncture (above inguinal ligament)
Posterior wall puncture
Hypothesis—Communication of femoral sheath
with retroperitoneal compartment
With contralateral access, techniques to control
hemorrhage
–balloon tamponade
–stent graft (>1–2mm than vessel diameter)
–surgical treatment if rest fails
Diagnosis
Back/ank pain
Vitals change (hypotension, tachycardia,
lethargy)
Usually occurs 2–3h later
Diagnosed using CT or repeat angiography
Pseudoaneurysm 0.2–0.5%
(diagnostic)
2–8%
(therapeutic)
Probable cause
Supercial femoral artery puncture
May also occur at brachial artery access site [6]
Diagnosis
Swelling, pain, and severe bruising at puncture
site
Complication- rupture (most serious), distal
embolization, local ischemia, infection, adjacent
neurovascular compression
USG-cystic lesion communicating with artery
with to and from signal [9]
AV Fistula <0.1% Probable cause
–communication between artery and vein during
puncture
Diagnosis
Palpation and auscultation
Colour Doppler (low resistive arterial signal in
arterial proximal to AVF and high-velocity
arterialized waveform in vein distal to AVF) [6]
May be diagnosed later during CT/MR
–conservative (small and asymptomatic)
–ultrasound-guided compression (success rate
74–86%) [7].
–ultrasound guided thrombin injection
without balloon catheter placement
(success rate 96%) [7].
–embolization (rare)—Gelfoam, coils
–stent graft
–surgical repair in selected cases (young
patients, infected PA, signicant local
compression, failed percutaneous treatment)
–mostly small and asymptomatic and resolve
spontaneously
–persistent cases may cause high output failure
and requires treatment
–prolonged bandaging and USG-guided
compression
–stent graft
–percutaneous coil or glue injection if long
stula
angiograms
Thrombosis
(Fig.10.7)
<0.5% Probable cause
Prolonged procedure
Large catheters (relative to vessel lumen)
Inadequate heparinization
Diagnosis
Diagnosed using USG or angiography
–catheter-directed thrombolysis (rt-PA,
urokinase), followed by angioplasty with/
without stent
–Thromboaspiration
–prevention
Keep patient hydrated
Minimize trauma
Use hydrophilic wires
Use vasodilators
Dissection [6] <0.5% Probable cause
Difcult access
Inadvertent manipulation of guidewire
Large sheaths
Signicant vessel calcication
High/low puncture
–non-ow limiting dissection— Conservative
management
–ow limiting dissection
Stent graft
Thrombolysis and angioplasty if associated
thrombosis
Diagnosis
USG-dissection ap may be seen
Angiography
Embolism <0.5% Small thrombus migrating distally Immediate surgical or percutaneous
thrombectomy
R. Jain et al.
*
with/
(continued)
AS
10 Vascular Access
Table 10.7 (continued)
Complication Incidence Salient features Treatment and precaution
Contrast-induced
nephropathy
Infection Rare Probable cause
Nerve damage Rare Probable cause
*
Lyophilized human thrombin and calcium chloride solution reconstituted in 2ml syringe (500 IU heparin/ml solution). The tip of needle is
inserted in pseudoaneurysm, and the puncture of neck should be avoided. Inject multiple small volumes and observe for thrombosis rather than one
single large volume
Rare –low osmolality contrast agent
local site infection may cause systemic infection
hardware related
neural compression by large hematoma or
pseudoaneurysm
–reducing amount of contrast
–adequate hydration
–strict antihygienic measures
–antibiotics
101
CF
Fig. 10.7 Common femoral artery thrombosis post prolonged angiography procedure. Color Doppler image depicting the thrombus with the
common femoral artery with distal reformation of supercial femoral
artery through collaterals
FA
rial puncture. The needle is kept steady with one hand once
there is blood return and guidewire is gently introduced with
the other hand through the hub. Access is then secured by
advancing sheath assembly over guidewire. Depending on
the procedure, CFV can be punctured in antegrade or retrograde direction.
Post-procedure Care 5–10 min compression is sufcient
for most femoral venous punctures. Leg is immobilized for
3–4h post procedure.
Complications The complications include deep venous
thrombosis at puncture site, accidental arterial injury and
rarely air embolism. Hematoma and bleeding complications
are rare with venous puncture, however may occur in
deranged coagulopathies.
10.10.2 Internal Jugular Vein
Site Selection Right jugular vein in the midportion of the
neck is the optimal site. Low access is preferred for tunneled
catheters (to avoid acute angulation).
Principles and Technique
It is useful access for placement
of catheters, many diagnostic and therapeutic venous procedures. Guided access using ultrasound is preferred to assess
patency of vessels and also avoid complications like carotid
artery puncture and pneumothorax. The location of the vein
in relation to the artery, anechoic lumen, compressibility and
respiratory variation in size should be noted. Preferably
patients leg should be elevated or patient placed in
Trendelenburg position to dilate IJV. The vein is accessed
under ultrasound guidance until the needle tip is seen within
lumen or blood is aspirated. Fluoroscopy can help in visualization of needle in lung. In case of suspected arterial puncture, needle should be pulled out and repuncture should be
done after compression; small amounts of contrast can be
injected to conrm position in case of doubt. After successful
venipuncture, guidewire is advanced and it goes easily to the
right atrium, also to IVC in many patients. Access is secured
using sheath or catheter advanced based on the procedure.
Post-procedure Care Compression for 5–10 min is sufcient for jugular vein puncture. Bedrest for 1–2h post procedure is recommended.
Complications Jugular vein puncture is associated with a
low rate of complication. However rarely potentially lethal
air embolism may occur. Large amounts (20–30 ml) may
cause pulmonary outow tract obstruction, small amounts
are harmless. To avoid this complication patients should be
placed in Trendelenburg position or advised to perform
Valsalva maneuver when the catheter or needle is open. In
case of air embolism, the patient’s vitals (blood pressure and
oxygen) should be checked. Unstable patient should be
placed in the left decubitus position to allow air to get trapped
in the right atrium; air may be aspirated from the right atrium
using a catheter. Stable patient is observed for a few minutes
until air is absorbed. Puncture site thrombosis is less common, local site hematoma is also rare.
102
R. Jain et al.
10.10.3 Subclavian Vein Access
The preferred site for subclavian vein puncture is lateral
aspect of clavicle along the anterior aspect of the rst rib. It
can be done under ultrasound or uoroscopy. The technique
is similar to IJV. The limitation of ultrasound is nonvisualization of structures posterior to vein, i.e., ribs and
lungs due to shadowing. Limited venogram may be taken by
injecting 10–20ml contrast through forearm vein for patency
of central vein and localization of subclavian vein prior to
uoroscopic-guided puncture. Micro-puncture set is used,
and the needle is advanced until aspiration of blood or when
the needle hits the rst rib.
10.10.4 Upper Extremity Vein Access
Basilic vein is the most preferred. It is usually punctured
immediately above the cubital fossa. Basilic vein is preferred
since it is larger and more direct communication with axillary vein. Another option is cephalic vein. It is relatively
safe, however small in size.
Other less common options that can be used for intervention are IVC, median antecubital vein, external jugular vein,
and popliteal, saphenous, and tibial veins.
10.11 Conclusion
The procedure should be planned before hand and the right
access chosen. Prociency in different vascular accesses is
the key for safe and successful performance of several endovascular procedures. Knowledge of anatomy, variations, and
hardware is necessary. Ultrasound and uoroscopy are useful in successful placement of vascular access sheaths, minimizing the procedure-related complications.
References
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EA, Klass D, Patel S, Schiro BJ, Walker TG, Guimaraes M.Society
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https://doi.org/10.1016/j.jvir.2020.12.013. Erratum in: J Vasc Interv
Radiol. 2021 Jul;32(7):1100. PMID: 33933252.
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Epub 2020 Aug 28. PMID: 32901463; PMCID: PMC7772376.
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2014 Nov 18. PMID: 25454654.
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Part II
Vascular Interventions
Neurointerventions Including Aneurysm Interventions
LeveJosephDevarajanSebastian
andNikhilaGunnaReddy
11
Key Messages
1. With latest advancements in interventional techniques, a
wide spectrum of neurovascular diseases can be treated
by endovascular approach.
2. Many of the intracranial aneurysms can be successfully
treated by endovascular interventions.
3. A detailed knowledge of the morphology, pathology, and
techniques plays a pivotal role in the success of these
procedures.
4. Updated insight into current guidelines and hardware
advances is essential.
11.1 Introduction
Fundamental aspects of vascular access, i.e., femoral or
radial artery access and basic angiographic methods, are
described elsewhere in the book. Here, we shall highlight the
key aspects relevant to the neuroangiography. Understanding
the indications and goals of angiography and proper counselling of the patient are important prerequisites even before
mobilizing the patient into the angiographic suite for the
procedure.
(1). Vascular Access
(i) For adults, 5F femoral sheath is generally suf-
cient for diagnostic cerebral or spinal angiography.
In case of radial access shorter sheath is used.
(ii) For therapeutic procedures, it may be exchanged
for a 6F–9F sheath depending on the exact endovascular treatment plan, as many of them require a
co-axial system with a long sheath. For those
requiring a 6F long sheath, it is a good idea to place
a 8F short sheath at the puncture site.
L. J. D. Sebastian (*) · N. G. Reddy
Department of Neuroimaging and Interventional Neuro-radiology,
All India Institute of Medical Sciences, Delhi, India
(iii) One should be extra careful during femoral punc-
ture of patients on dual antiplatelets (for planned
stenting or stent assisted procedures), as multiple
puncture attempts or inadvertent venous puncture
can cause large hematoma.
(iv) Immediately, after the vascular sheath is placed a
bolus heparin dose of 2500IU is given before pro-
ceeding with the angiography.
(2). Cerebral Angiography
(i) Carefully inspect the chest radiograph or any CT
angiography available to get an idea of the aortic
arch anatomy of the individual for planning a
swift and smooth angiographic procedure.
Sometimes, an arch angiography using a pigtail
and pressure injector is very helpful.
(ii) Generally, a Picard or Vert with multipurpose
shape is enough for catheterizing the individual
arch branches. But SIM-1 or 2 may be needed in
those with difcult arch. Use of road map and
guidewire is strongly advised while selectively
catheterizing each of the neck artery. Other precautions to be taken are listed below.
(iii) Regularly ush the catheter with heparinized
saline.
(iv) It is ushed every 90s, and before and after each
wire exchange.
(v) Tip of the syringe is always checked for any air
bubbles before injecting.
(vi) Once the catheter is in position, we run a uro to
make sure the catheter is in the right place without any wedging.
(vii) If the catheter is wedging against any artery, the
back ow will be impaired.
(viii) After double checking, the patient is instructed
not to move and runs are taken with exponential
increase in velocity of the injection for a smooth
run.
(ix) In ECA run, slow injection is given to prevent any
reux into the ICA.
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
S. H. Chandrashekhara (ed.), Textbook of Interventional Radiology, https://doi.org/10.1007/978-981-97-9601-4_11
105
106
L. J. D. Sebastian and N. G. Reddy
(x) For many of the indications, six vessel cerebral
angiography, that is, injection of bilateral ICA,
ECA and VA, is generally needed though it can be
tailored according to the specic clinical situation. Anteroposterior (AP) and lateral projections
are regularly taken. Additional oblique views are
taken on the side of the disease identied. In case
of aneurysms, three-dimensional rotation
angiography (3DRA) of the harboring vessel(s) is
essential.
(3). Spinal Angiography
(i) Careful study of the available CT and MRI images
to approximately localize the level of the spinal
vascular disease in the given patient. This will help
focus on the, otherwise lengthy, spinal angiographic examination toward the pathology.
(ii) It may be necessary to inject segmental arteries at
all the spinal levels for some indications, especially
in suspected cases of spinal dural AVFs. For cervical levels, bilateral subclavian and vertebral artery
injections and sometimes ECA and thyrocervical
artery injections are needed. For dorsal level bilateral D4–D12 intercostal arteries and for lumbar
L1–L4 bilateral lumbar arteries are to be injected.
Finally, bilateral common and internal iliac arteries
injections complete the spinal angiography.
(iii) Flush aortography is not a substitute for individual
segmental artery injection. At best, it may help to
localize the origin of the intercostal or lumbar
artery origin.
(iv) Choice of diagnostic catheter depends on the angi-
ographer’s training and experience. Generally, an
RC2 or RC1, or sometimes SIM2, is used. The last
one may be particularly helpful in atherosclerotic,
dilated aorta.
11.2 Neurovascular Interventions
With current advancements in interventional techniques, a
wide spectrum of neurovascular diseases can be treated by
endovascular means with relatively less morbidity and mortality. In fact, the endovascular method is the best and only
option for some of these disorders. A detailed description of
all of these procedures and their nuances will consume volumes. Herein, we have given a brief description of them
under the following sub-sections.
1. Endovascular management of intracranial aneurysms.
2. Endovascular management of intracranial arterio-venous
malformations/stulas (AVMs/AVFs).
3. Endovascular interventions in ischemic stroke.
4. Miscellaneous cranial interventions.
5. Spinal vascular interventions.
This chapter covers the endovascular management of
intracranial aneurysms. Other topics are covered in subsequent chapters.
11.3 Endovascular Management
ofIntracranial Aneurysms
11.3.1 Introduction
Intracranial aneurysms are a heterogenous group of disorders that can be broadly termed as aneurysmal vasculopathies [1]. Accordingly, they have varied clinical presentations,
the most ominous of them being sub-arachnoid hemorrhage
(SAH). As of date, most of the cranial aneurysms can be
managed by endovascular means and constitute the major
part of a neurointerventionist’s practice. Hence, a thorough
understanding of the disease and its management, including
that of SAH and its complications, has become essential for
any practitioner in this domain.
11.3.2 Pathology andClinical Aspects
Various studies, mainly in the Western population, indicate
that 3–5% of the general population harbor intracranial aneurysms [2]. Pathologically aneurysm can be viewed as a disease process(es) involving or culminating in the arterial wall.
Aneurysms are more common in intracranial circulation than
any other. Lack of external elastic lamina in intracranial
arteries can partly explain this. Certain genetic factors may
be associated with or predispose to aneurysm formation as
exemplied by increased incidence of intracranial aneurysms in ADPKD and Marfan’s [3]. Hemodynamic factors,
such as hypertension, and modiable factors, such as smoking, play major roles in the aneurysm formation or in its
growth.
The intracranial aneurysms can be divided into various
groups depending on their morphology, etiology, presentation, etc. Based on their morphology, they are classied as
saccular or fusiform [4]. Saccular or berry aneurysms are
commonly found at branching points of arteries, have a
roughly spherical shape with a neck connecting it to the parent artery, and are called true aneurysms as their wall has all
the layers of a normal arterial wall. Fusiform aneurysms are
usually dissecting aneurysms, have an oblong shape, and
generally lack a neck. Based on size, aneurysms can be
labeled as small (2–10 mm), large (10–25 mm), or giant
(>25 mm). Based on etiology, they are divided into idiopathic (Berry), dissecting, mycotic, oncotic, traumatic, and
ow-related aneurysms. Based on their presentation, they are
divided into ruptured and unruptured aneurysms. Unruptured
aneurysms are further classied into symptomatic and
asymptomatic. In day-to-day clinical practice, a nomencla-
11 Neurointerventions Including Aneurysm Interventions
107
Table 11.1 Classication of intracranial aneurysms based on location
Anterior circulation Posterior circulation
1. ICA (named based on the segments
of ICA)
1.1 extra-dural - V4 segment
- petrous/laceral/cavernous - PICA origin
1.2 at the dural ring - distal PICA
- carotid cave 2. Basilar artery
1.3 Supraclinoidal - proximal/ mid/distal
- Carotico-ophthalmic - AICA origin
- superior hypophyseal - SCA origin
- posterior communicating - basilar top
- anterior choroidal 3. PCA
2. Anterior communicating artery
(A-com)
(i) A-com - P2 or distal PCA
(ii) A1-A-com junction
(iii) A-com A2 junction
3. ACA
- A1 ACA
- A2 ACA or distal ACA
4. MCA
- M1 MCA
- MCA bifurcation
- distal MCA
1. Vertebral artery
basilar
- P1 PCA
ture/classication of aneurysms based on location is commonly used as outlined in Table 11.1. A differentiation of
side wall and bifurcation aneurysms is also useful in the
endovascular treatment viewpoint.
11.3.3 Clinical Presentation
The most dreaded event in the evolution of any aneurysm is
its rupture. Rupture of an intradural aneurysm leads to SAH
(or rarely brain parenchymal or ventricular bleed), which is a
severe medical condition with around 15% of patients prone
to succumb before reaching a healthcare facility [5]. On the
other hand, rupture of an ICA aneurysm in an extradural
location (cavernous segment, for example) can present with
carotico-cavernous stula or life-threatening epistaxis or ear
bleed.
Aneurysms can also have non-hemorrhagic presentations.
Large aneurysms can present due to mass effect on adjacent
neural structures like brainstem [6], cranial nerves, etc., as
commonly noted in posterior circulation. Supraclinoid ICA
aneurysms can exert a mass effect on optic chiasma; posterior cerebral or superior cerebellar artery aneurysms can lead
to third nerve palsy.
Large partially thrombosed/dissecting aneurysms can be
a source of embolic stroke. Seizures are a rare presentation
of intracranial aneurysms [7].
Table 11.2 Location of sentinel hematoma and associated probable
aneurysm
Location of the sentinel hematoma Probable aneurysm
Anterior interhemispheric ssure
extending to septum pellucidum/
frontal horn
Anterior interhemispheric ssure
along the genu or body of corpus
callosum
Sylvian ssure MCA bifurcation
Either side of suprasellar cistern ICA-P com aneurysm
Suprasellar cistern with temporal horn
extension
Prepontine cistern Basilar artery aneurysm
Cerebello-medullary cistern PICA aneurysm
Fourth ventricle Distal PICA aneurysm
A-com aneurysm
DACA aneurysm
aneurysm
ICA-choroidal aneurysm
11.3.4 Imaging ofAneurysms
In the acute presentation of thunderclap headache, CT is the
rst-line investigation to detect and grade SAH.Currently,
modied Fischer’s scale is the most simple, useful, and
widely used score to assess the severity of SAH on the initial
NCCT.CT also aids inlocating the ruptured aneurysm. The
location of the sentinel hematoma, which is the primary site
of bleed into the subarachnoid space and the contiguous or
isolated parenchymal or ventricular extension, if present, can
all point the location of the ruptured aneurysm as listed in
Table11.2. In some cases, with large ruptured aneurysms the
aneurysmal ghost sign can be appreciated which is seen as a
hypodense area within the hyperdense SAH.
In the acute setting, the role of MRI/MRA is limited. In
equivocal cases with strong suspicion of SAH, Flair is superior to CT in demonstrating SAH as a hyperintense signal in
subarachnoid spaces. In patients presented with SAH who
are harboring multiple intracranial aneurysms, vessel wall
imaging has a special role to identify the one that has ruptured. This role can be extended to the follow up of unruptured aneurysms where wall enhancement can be used as an
indicator of aneurysmal instability [8]. TOF MRA is also
used for follow up in cases of unruptured aneurysms treated
conservatively. In patients with renal failure or contrast
allergy, TOF COW is the investigation of choice.
CT angiography is useful for studying the structure and
relations of intracranial aneurysms. Modern-day MDCT
advanced image processing techniques provide exquisite
images of vascular anatomy and a wide array of measurements. In fact, many centers use CTA as a standalone vascular imaging for treatment planning. Of the many
advantages of CTA, rapid acquisition and vivid depiction
of aortic arch and neck vessel anatomy need special mention [9].
108
L. J. D. Sebastian and N. G. Reddy
However, DSA with 3D rotational angiography remains
the gold standard for the detection and complete morphological evaluation of all types of intracranial aneurysms—
whether ruptured or not. DSA has the highest spatial and
temporal resolution and hence can detect aneurysms of even
less than 2 mm size [10]. The following points are
pertinent:
1. Six vessel angiography (bilateral ICA, ECA, and VA) is
essential in SAH settings.
2. Three-dimensional rotational angiography of whichever
vessel/circulation harboring an aneurysm is to be
performed.
3. Complete morphological evaluation requires several
measurements as detailed in the next section.
4. Cross-compression studies are often required to know the
patency of the circle of Willis, especially when large or
giant aneurysms involving ICA or vertebrobasilar system
are found.
5. In SAH cases, if the initial DSA is negative, repeat exam-
ination is advised after 1–6weeks.
If two or more family members have aneurysms/SAH, or
in patients with ADPKD and other connective tissue disorders, periodic screening for aneurysms can be done by CTA
or MRA.
treated. Patients with documented enlargement of the
aneurysm during follow up should be offered treatment.
11.3.7 Complete Morphological Evaluation
ofAneurysms
Several measurements concerning the aneurysm and the
artery harboring it are crucial in planning the endovascular
treatment in a given patient. A typical saccular aneurysm is
construed to have a neck and a body or fundus. Neck denotes
the defect or hole in the arterial wall leading into the aneurysm. The body can have one or more psuedolobules, which
represent point(s) of rupture. Adjoining dural or arachnoid
folds can also cause true lobulations in the growing
aneurysm.
The most important dimensions in treatment planning as
depicted in the image above are as follows:
• Aneurysmal neck.
• Aspect ratio=height/neck.
• Neck-dome ratio.
• Parent vessel diameter: proximal, distal, and at the level
of the aneurysm.
11.3.5 Management ofIntracranial Aneurysms
Endovascular techniques have rapidly advanced in recent
years. Today, most of the intracranial aneurysms, barring a
few, can be successfully treated by endovascular means, as
illustrated below. This section begins with a brief outline of
indications for treatment followed by a description of morphological evaluation as required for treatment planning.
Finally, individual techniques are explained through illustrative case examples in the format of a pictorial essay.
11.3.6 Which Aneurysms toTreat?
• All acutely ruptured aneurysms are to be treated as early
as possible, to prevent re-rupture.
• Treatment of asymptomatic intracranial aneurysms: This
depends on the natural history or rupture potential of an
aneurysm. According to ISUIA trial, size and location are
independent predictors of aneurysm rupture. Anterior circulation aneurysms of <7mm have very low risk (~0%)
of rupture. Posterior fossa aneurysms <7mm still have a
risk of rupture.
• Prior history of aneurysmal SAH is an independent risk
factor, irrespective of the aneurysmal size, and should be
Height
Width
Neck