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144 Chapter 15 Intravascular ultrasound
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15.4 Three ways to determine vein diameter and measurement variation.
(Images courtesy of Dr. Paul Chouinard.)
15.5 Various presentations of post-thrombotic scars in veins.
evident on the initial venogram. However, a scar develops
after DVT resolution within the vein wall (i.e., intramural) and in the lumen (i.e., intraluminal) that affects the
expansion, lumen size, and compliance of the vein. This is
often not evident with a venogram. The conguration and
distribution of a post-thrombotic scar can be variable (Figure15.5). Unlike with nonthrombotic lesions, the stenosed
post-thrombotic vein is treated with balloon dilation to
the appropriate (i.e., idealized) size and stented to the
same size in a 1:1 ratio. Areference vessel is less important in calculating the severity of the stenosis or diameter
of the vein in these patients suffering from clinical CEAP
4–6 CVH. The veins are generally diffusely narrowed and
the stents well-anchored over a long distance. What is
15.4 IVUS-identified venous anatomy affects stent placement strategy 145
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critical, however, is that all scarred segments of the vein
are treated so that no inow or outow lesions to the stent
are left unaddressed (Figure15.5). The extent of damaged
vein with scarring is much more accurately detected with
IVUS than with venogram.
an angioplasty and stents will affect stent patency and
clinical success. What is also paramount in these patients
is to use IVUS to conrm both adequate stent expansion
and vein lumen gain (9), which predicts adequate ow to
prevent stent thrombosis from relative stasis. Conrming
diffuse vein wall apposition (Figure15.6) is also important
to ensure stent xation and decrease concerns about stent
migration.
Treating all scarred veins with
15.4 IVUS-IDENTIFIED VENOUS
ANATOMY AFFECTS STENT
PLACEMENT STRATEGY
Helpful information gained from IVUS includes pelvic
vein anatomy (Figure15.7). Identifying the junction of the
common iliac vein and inferior vena cava (IVC) and where
the point of compression might be relative to that conuence can be helpful for successful stenting. It is clear with
IVUS that the inferior portion of the IVC is sometimes the
point of compression rather than the common iliac vein
and that when the common iliac vein is compressed on
the left or right, it is not always adjacent to the junction
with the IVC, but rather is sometimes 2–3 centimeters
caudal to that point. Additionally, identifying the junction
of the internal (IIV) and external iliac (EIV) veins to form
the common iliac vein can be helpful in determining stent
length. In some patients the distance from IVC to this conuence of the IIV and EIV can be short, while in other
patients longer. An additional benet of identifying the
junction of the external and internal iliac vein is to allow
identication of the mid-portion of the external iliac vein
which dips into the pelvis. Positioning the cranial or caudal
end of a stent in the mid-portion of the external iliac vein
which is positioned in the deepest part of the pelvis often
leads to distortion of the nonstented adjacent vein segment,
which may have long-term hemodynamic effects. Also, as
the stent straightens over time, it can erode through the
side of the vein in these curved sections of the vein. Therefore, it is better to plan the end of a stent to be in the upper
or lower third of the external iliac vein to avoid potential
future complications. In all patients with stents extending
into the common femoral vein, and especially those who
have diffuse post-thrombotic scarring, IVUS is particularly
helpful in identifying the inow vessels to the common
femoral vein, namely the femoral vein and deep femoral
vein. In these patients, the femoral vein is often diffusely
diseased from prior DVT and scarring To have adequate
inow to a common femoral vein stent, it is important to
end the common femoral vein stent cranial to the junction
with the deep femoral vein (Figure15.8). In post-thrombotic patients, it is
eased and widely patent inferior common femoral vein or
to the junction of the common femoral vein with the widely
patent deep femoral vein to ensure adequate inow to the
stent and avoid stent thrombosis and gain long-term stent
important to stent to either a non-dis-
15
15.6 Stent and vein wall apposition
146 Chapter 15 Intravascular ultrasound
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15.7 Pelvic vein anatomy easily identied with IVUS. (for abbreviations, see text).
15.8 Venogram and IVUS detected post-thrombotic occlusive or near-occlusive scars In the CFV, DFV and FV.
patency. There are often two deep femoral veins identied
with IVUS, and conrming the location and the absence of
scarring at the junction with the common femoral vein provides important information about where to land the stent.
In the setting where IVUS and venogram determine that
the common femoral, femoral, and deep femoral veins are
all diffusely stenosed due to a post-thrombotic scar, CFV
stenting should be avoided to prevent stent thrombosis due
to poor inow, which may actually worsen the patient’s
clinical condition.
15.5 CONCLUSION
The more experience we gain with IVUS for the diagnosis
and treatment of deep venous occlusive disease, the more
critical to success it becomes and the more questions about
optimal use arise. It is not enough to pull the IVUS catheter
through the length of vein segments of interest to identify
stenosis and calculate its severity. Relying on dynamic IVUS
imaging to expand your real-time understanding of venous
anatomy and pathology is important to avoid false-positive
lesions and undersizing stents. Identifying the pelvic venous
anatomy, especially the deep femoral vein, as an adequate
inow vessel in those patients with diffuse post-thrombotic
disease may prevent stent thrombosis. This technical detail
whereby adequate stent inow is assured is just as important for procedural success as post-stenting anticoagulation.
IVUS conrmation of stent expansion and wall apposition
and adequate and disease-free venous inow and outow
are the details of each stent case necessary to improve success.
Further research on what is an IVUS-determined crit-
ical lesion and whether it is the same for all degrees (i.e.,
References 147
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clinical classes CEAP 4–6) of advanced symptomatic CVH
needs to be performed. Additional studies on how to best
use IVUS to calculate vein diameters to assure proper stent
selection is also necessary.
Excellent research has been done to date and has beneted a large group of patients. More investigation is needed
to rene both our imaging and image interpretation to better
guide treatment and reliably obtain optimal patient outcomes.
Consensus Statements 15.0 of the American Venous Forum on the use of intravascular ultrasound
No. Consensus Statements
15.1 A >50% cross-sectional area reduction measured by IVUS in symptomatic patients results in measurable clinical improve-
ment following iliac vein stent placement.
15.2 IVUS is helpful to select the appropriate size of venous stents.
15.3 IVUS-identied pelvic venous anatomy aids in the placement of iliac vein stents.
REFERENCES
★ Systematic review
1. Raju S, Neglen P. High prevalence of
nonthrombotic iliac vein lesions in
chronic venous disease: Apermissive
role in pathogenicity. J Vasc Surg. 2006
Jul;44(1):136–144
2. Neglén P, Hollis KC, Olivier J, Raju S.
Stenting of the venous outow in chronic
venous disease: Long-term stent-related
outcome, clinical, and hemodynamic
result. J Vasc Surg. 2007 Nov;46(5):
979–990
3. Neglen P, Raju S. Intravascular ultrasound
scan evaluation of the obstructed vein. J
Vasc Surg. 2002 Apr;35(4):694–700
4. Gagne PJ, etal. Venography versus
intravascular ultrasound for diagnosing
and treating iliofemoral vein obstruction.
J Vasc Surg Venous Lymphat Disord. 2017
Sep;5(5):678–687
5. Murphy E, etal. Pivotal study
evaluating the safety and effectiveness
of the Abre venous self-expanding stent
system in patients with symptomatic
iliofemoral venous outow obstruction.
Circulat Cardiovasc Intervent. 2022
Feb;15(2):2
6. Black S, etal. ABRE study: Clinical
outcomes through 36 months. Presented at
the American Vein and Lymphatic Society,
New Orleans, LA, October, 2022
7. Sayed MH, Salem M, Desai KR, O’Sulli-
★
van GJ, Black SA. Incidence, outcome and
management of venous stent migration:
Asystematic review. J Vasc Surg Venous
Lymphat Disord. 2022;10:482–490
8. Rossi FH, etal. Randomized doubleblinded study comparing medical
treatment versus iliac vein stenting in
chronic venous disease. J Vasc Surg Venous
Lymphat Disord. 2018 Mar; 6(2):183–191
9. Gagne PJ, etal. Analysis of threshold
stenosis by multiplanar venogram and
intravascular ultrasound examination for
predicting clinical improvement after iliofemoral vein stenting in the VIDIO trial. J
Vasc Surg Venous Lymphat Disord. 2018
Jan;6(1):48–56
10. Chouinard P, etal. Sources of error in
measuring vein size. Presentation at AVLS,
Denver, CO, October2021
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CHAPTER
16
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Computed tomography and magnetic
resonance imaging in venous disease
Thanila A. Macedo, Terri J. Vrtiska, and James F. Glockner
16.1 INTRODUCTION
Current diagnostic evaluation of disorders of the venous
system has beneted from advances in state-of-the-art computed tomography (CT) and magnetic resonance imaging
(MRI) applications. An understanding of the fundamentals
and the appropriate utilization of each technology will
provide useful information for medical management and
decisions regarding surgical or endovascular interventions
for venous disease.
16.2 IMAGING TECHNOLOGIES: CT OF
VENOUS DISEASE
During the past decade, CT has become a standard noninvasive imaging modality for the depiction of a wide variety
of vascular anatomies and pathologies. Modern CT acquisitions have evolved from single-detector spiral scanners to
multichannel helical CT examinations. More recently, 256slice, 320-slice, and dual-energy CT systems have become
available in many practices and have replaced catheter-directed vascular imaging for many diagnostic studies. The
proper application of modern CT techniques provides an
extremely accurate, time-efcient, and cost-effective diagnostic evaluation prior to surgical or endovascular intervention.
The two dominant advantages of CT are the speed and
resolution of image acquisition. Modern CT acquisitions
can be acquired in less than a minute during a single breathhold, minimizing motion artifact. In addition, submillimeter resolution details are available for accurate depiction of
the imaging ndings, which can be communicated to clinicians using advanced postprocessing techniques and 3D
displays (Figure16.1). One additional distinct advantage
of CT compared with MRI is the ability to demonstrate
calcied densities such as calcied granulomatous lymph
nodes as a cause of superior vena cava (SVC) obstruction
on precontrast acquisitions.
The two primary disadvantages of CT imaging of the
venous system include radiation exposure and the necessity
for administration of iodinated contrast material. Atypical
abdominal and pelvic CT evaluation includes a radiation
exposure of approximately 5–10 mSv. Ongoing efforts
within the CT physics community are focused on optimizing the necessary radiation required for CT acquisitions by
tailoring the dose to the individual patient size via modulation of the radiation beam.
contrast material is necessary for accurate evaluation of the
venous system, and therefore, patients with a signicant
allergic reaction to iodinated contrast material or signicant decrease in renal function should be evaluated with
alternative imaging techniques, including ultrasound or
MRI.
1
Administration of iodinated
16.2.1 Clinical applications
16.2.1.1 SVC and brachiocephalic veins
CT evaluation of the SVC is most commonly performed
for the evaluation of acute or chronic occlusive changes
and has been shown to be a useful noninvasive imaging
technique for the diagnosis of SVC and central venous dis-
2–5
orders.
ing endovascular stent patency or postoperative changes
of surgically placed bypass grafts, can also be performed.
Regardless of the indication, CT acquisitions are optimally
performed by the simultaneous injection of the antecubital veins using 90–100 mL of dilute (1:3 contrast-to-saline
ratio) contrast material in each extremity at an injection
rate of 2–3 mL/second (direct CT venogram). The bilateral arm injections provide homogeneous opacication of
the innominate veins and SVC and avoid potential artifacts
from unopacied blood within the central venous structures (Figure16.2). Subsequent injection of 20–30cm
saline is helpful for ushing the contrast material from the
brachial and axillary veins into the central venous system.
Alternatively, indirect CT venogram can be obtained with
injection of full concentration contrast through a peripheral or central intravenous access and delayed image acquisition. CT acquisition using thin collimation (1–2mm) is
useful in order to provide both traditional axial images and
appropriate reconstructions that can be analyzed in the
coronal, sagittal, or tailored off-axis planes. Careful review
of the axial images and dedicated reconstructions are useful for optimal visualization of venous patency, obstructed
venous segments, intraluminal thrombus, and collateral
venous pathways.
Evaluation of postprocedural changes, includ-
3
of
DOI: 10.1201/9781003328971-18
149149
150 Chapter 16 Computed tomography and MRI in venous disease
(a)
(b)
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16.1 Current computed tomography technology combined with tailored acquisition techniques and postprocessing applications
provide accurate depiction of (a) the thoracic and (b) abdominal venous vasculature.
16.2 (a, b) Contrast-enhanced axial and (c) coronal computed tomography of the chest demonstrate artifactual low-density lling
defects because of unopacied blood ow from the right jugular vein and unopacied blood from the left brachiocephalic vein entering the opacied right brachiocephalic vein (a and c, arrows) and the superior vena cava (b and c, arrowheads).
16.2 Imaging technologies: CT of venous disease 151
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16
16.3 Acute thrombotic occlusion. (a) Coronal CT image acquired with iodinated contrast material injected simultaneously via bilat-
eral antecubital IV access shows low-attenuation thrombus in distended right and left brachiocephalic veins (arrows) consistent with
acute deep vein thrombosis. (b) Subsequent postlysis catheter venogram with widely patent brachiocephalic veins.
16.4 Chronic occlusive changes. 3D reconstruction of indirect CT venogram with volume-rendered image. (a) There is nonopacica-
tion of the right (arrow) and left (arrowhead) brachiocephalic veins with associated chest wall and lower neck collaterals. (b) Another
patient with absent right subclavian and brachiocephalic veins (white arrow) with chest wall collaterals and prominent azygous vein
(black arrow). The right axillary remains patent (arrowhead). Note the presence of a left subclavian central venous catheter.
On contrast-enhanced (CE) CT images, acute thrombus
within the SVC or central venous structures is characterized
by a low-attenuation lling defect within the lumen of the
vessel (Figure16.3). The involved venous segment may be
normal caliber or expanded. Chronic occlusive changes are
most commonly visualized as small, nonopacied, brotic-appearing linear densities or an absent venous segment.
Extensive upper chest wall and azygous collaterals can be
precisely depicted by 3D images (Figure16.4).
An advantage of evaluation of the SVC and central
venous structures by CT rather than catheter venography is
the ability of CT to accurately depict the underlying pathology causing venous occlusive
cause of obstruction of the SVC and upper venous structures is malignancy, most commonly pulmonary neoplasm.
The obstruction may result from extrinsic compression due
to primary or metastatic neoplasm or from direct invasive
changes. Iatrogenic occlusive changes are increasingly seen
changes. The most common
152 Chapter 16 Computed tomography and MRI in venous disease
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16.5 (a) Volume-rendered 3D reconstruction of indirect CT venogram in a patient with SVC syndrome performed for surgical plan-
ning. No peripheral IV access could be obtained, and contrast was injected through a femoral central line.
botic changes are demonstrated with a small left internal jugular in the upper neck (arrowhead) and absent in the lower neck. Bilateral
subclavian, brachiocephalic, and SVC stents are occluded with multiple lower neck and chest wall collaterals as well as a prominent
azygous vein (curved arrow). Preserved venous inow through a patent right internal jugular vein (arrows) is shown. Repeat postoperative CT venogram with volume-rendered
vein–to–right atrium bypass graft without signicant stenosis. Note the detailed anatomy displayed by the volume-rendered image
showing the antibiotic beads (arrows) adjacent to the prosthetic graft in this immunosuppressed patient.
(b) and curved planar reformat (c) 3D reconstruction shows a patent right internal jugular
(a) Chronic-post throm-
16.6 Contrast-enhanced axial (a) and coronal (b) computed tomography demonstrates ow artifact (arrow) from unopacied blood
from the infrarenal inferior vena cava streaming into the juxtarenal (IVC) with admixture of opacied blood from the renal veins
(arrowhead).
as the reason for obstruction due to widespread use of
central venous catheters and transvenous cardiac devices.
Postradiation changes may also result in iatrogenic SVC
obstruction. Another common cause of SVC obstruction
includes granulomatous disease. Anatomic variants of the
SVC can also be accurately visualized by CT evaluation,
such as a left-sided SVC.
CT is used preoperatively to delineate the extent of
disease (Figure16.5) and help with surgical or endovascular treatment planning. Demonstration of the inow,
obstructed segment, and outow is important information
required prior to intervention. This is especially important when protocoling the exam and deciding on the area
of body coverage to be included in the study. CT is the
preferred modality and is widely used postoperatively to
evaluate central venous bypass or endovascular stents
where ultrasound has a limited role (Figure16.5). Ultrasound cannot directly visualize the SVC or brachiocephalic
veins due to the deep anatomic location in the chest and
lack of appropriate scanning window.
16.2.1.2 Inferior vena cava and iliac veins
Accurate evaluation of the inferior vena cava (IVC) requires
knowledge of potential ow artifacts that are especially
prominent due to the rapid acquisition provided by modern CT scanning (Figure16.6). In addition, knowledge of
anatomic variation of the IVC is important for determining
the accurate evaluation of ndings due to anatomic variation rather than pathology (Figures16.7 and 16.8).
6–9
The
16.2 Imaging technologies: CT of venous disease 153
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16.7 Contrast-enhanced axial computed tomography (a) and volume-rendered 3D reconstruction (b) demonstrate the anatomic
relationships of a retroaortic left renal vein (arrows).
16
16.8 Contrast-enhanced axial (a) and coronal (b) computed tomography demonstrates duplication of the infrarenal inferior vena
cava (IVC) with a right-sided (arrow) and left-sided infrarenal IVC (arrowhead).
ow artifact visualized within the IVC is due to the unopacied blood from the lower extremities entering the infrarenal IVC, whereas the suprarenal IVC receives an admixture
of opacied blood due to the rapid transit of the contrast
material through the kidneys. Anatomic variants of the IVC
are due to persistent embryologic remnants. The prevalence
of the most common anatomic variants includes persistence
of a solitary left-sided IVC (<1%) and duplication of the
infrarenal IVC segment (1%–3%), retroaortic left renal vein
(2%–3%), and circumaortic left renal vein (2%–9%).
Optimal opacication of the IVC typically requires
delayed CT imaging at 90–120 seconds following the
administration of an appropriate volume of iodinated contrast material to allow homogeneous opacication of the
entire infrarenal cava. Typically, between 150 and 200 mL
of iodinated contrast is required for optimal venous opacication. As with the SVC, current CT evaluation provides
accurate off-axis display of the entire caval segment in any
orientation; however, the coronal display most commonly
provides the best depiction because of the craniocaudal
orientation of the IVC within the abdominal cavity. The
iliac veins require multiplanar evaluation due to tortuosity
and are often better displayed with curved planar reformat
3D reconstruction where the vein can be elongated and
entirely displayed in one image. The most common pathology depicted within the IVC is bland thrombus either due
7
to thrombotic disease and may be visualized within the
central cava and iliac veins (Figure16.9) or due to extension of thrombus from malignant occlusive changes (Figure16.10). Thrombus may also be visualized within venous
branches, such as the renal veins or common femoral veins
(Figure16.11). Tumor thrombus within the IVC is most
commonly due to local extension from adjacent organs
such as the kidneys (renal cell carcinoma), liver (hepatocellular carcinoma), or adrenal glands (adrenal cortical carcinoma). An uncommon cause of a lling defect within the
IVC is due to a primary tumor arising in the smooth muscle
of the IVC, as seen with leiomyosarcoma.
IVC may be traumatically disrupted (Figure 16.12). The
ability of the CT evaluation to display the orientation of
an IVC lter can be helpful for depicting migration (Figure
16.13a)
or thrombus (Figure16.13b).
10,11
Rarely, the
16.2.1.3 Pulmonary arteries
CT of the pulmonary arteries has largely replaced catheter-directed pulmonary angiography and ventilation and
perfusion scintigraphy (VQ scans) because of the wide
availability, rapidity of the scan’s acquisition, and the high
sensitivity and specicity (approaching 100%) for central
pulmonary emboli.
small subsegmental pulmonary emboli has been shown to
be less accurate, with a sensitivity of 83% and a specicity
12,13
In other studies, the detection of
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