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ABC
FIGURE 135 Stanford type A dissection. A, Axial multiplanar reconstruction (MPR) image. B, Coronal maximum-intensity projection (MIP). C, Three-dimensional
volume-rendered (3D-VR) image shows intimal flap in ascending aorta (arrow).
and subclavian arterio-occlusive disease20 (Fig. 13-6). Rotating MIPs
enable precise evaluation of the branch vessel origin without confounding signals from overlying vessels.
CONGENITAL ANOMALIES
Congenital lesions are well depicted with MRA. Aortic coarctation
appears as a discrete narrowing of the aorta distal to the left subclavian artery (
the stenosis, tortuosity of the aorta, and associated collateral ves-
21
sels.
Collateral flow assessment with MR velocity mapping can
accurately evaluate the hemodynamic significance of a coarcta-
22
tion.
Cine-MR imaging also permits diagnosis of a concomitant
Fig. 13-7). Magnetic resonance angiography depicts
bicuspid valve and possible aortic stenosis. Magnetic resonance
angiography is used after intervention to exclude complications
such as stenosis or aneurysm formation.
23
Magnetic resonance angiography also can distinguish between
coarctation and pseudocoarctation. Pseudocoarctation is a rare
asymptomatic anomaly in the descending thoracic aorta and is
characterized by an elongated redundant thoracic aorta with
buckling distal to the origin of the left subclavian artery. There is
no pressure gradient across the buckled segment. It is regarded
as a benign condition, although several reports demonstrate that
complications may occur.
24
THORACIC OUTLET SYNDROME
Thoracic outlet syndrome results from compression of the neurovascular bundle (subclavian artery and vein plus the brachial plexus)
at the thoracic inlet. Symptoms are typically from nerve compression; the brachial plexus is involved in up to 98% of cases. Magnetic
resonance imaging can demonstrate obstruction/compression of the
fat surrounding the brachial plexus, and of the subclavian vein and artery.
Magnetic resonance angiography is performed during abduction and
adduction maneuvers of the arm to simulate physiological compression of the veins and/or arteries to confirm the diagnosis (
Fig. 13-8).
Pulmonary Vessels
Radiofrequency ablation for atrial fibrillation has increased the
role of noninvasive pulmonary vein mapping before intervention
and for postprocedural surveillance for complications.
25
Magnetic
resonance angiography enables comprehensive planning of electrophysiological procedures with respect to number, location, and
size of the pulmonary veins (
erence standard for pulmonary embolism (PE),
Fig. 13-9). Multidetector CT is the ref-
26
although pulmonary MRA can be performed in patients with severe allergy to
iodinated contrast media (
Fig. 13-10). Time-resolved MRA can be
used to minimize venous contamination.27 Pulmonary artery aneurysms and stenoses can also be characterized with MRA.
Coronary Arteries
Because of its superior soft-tissue contrast, MRI provides excellent cardiac morphology and function data. The coronary arteries, however, remain elusive because of their small caliber, motion,
and tortuosity (
coronary arteries noninvasively in routine clinical practice is computed tomographic angiography (CTA).
appropriate for coronary anomalies,
purpose and can be performed with less than 1 mSv of radiation.
Fig. 13-11). The modality that can best image the
28
Coronary MRA is only
29
but CT is superior for this
173
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AB
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FIGURE 136 Thoracic magnetic resonance angiography (MRA). A, Coronal maximum-intensity projection (MIP). B, Three-dimensional volume-rendered
(3D-VR) image shows proximal left subclavian artery occlusion (arrow) and subclavian steal syndrome.
FIGURE 137 A, Oblique sagittal maximum-intensity projection (MIP) image shows aortic coarctation (arrow). B, Three-dimensional volume-rendered (3D-VR)
image shows larger field of view; extensive collaterals are evident (arrows).
Peripheral Artery Disease of the Lower
and Upper Extremities
Most peripheral artery disease (PAD) is due to atherosclerosis.
Other conditions altering arterial flow to the legs include peripheral artery aneurysms, popliteal artery entrapment, cystic adventitial disease, thromboangiitis obliterans (TAO), giant cell and
Takayasu's arteritis, and (rarely) FMD.
Magnetic resonance angiography evaluation of lower-extremity PAD
typically extends from the aortic bifurcation to the level of the ankle
and foot (
to evaluate vascular anatomy in patients with PAD to plan revascularization procedures. This enables identification and characterization of
all occlusive lesions, plus an evaluation of inflow and outflow vessels.
ening, thrombi, intramural hematoma, atherosclerotic plaques, and
Fig. 13-12). Magnetic resonance angiography is often used
Black-blood MRA images can assess the presence of wall thick-
174
AB
AB
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FIGURE 138 Thoracic outlet synd-
rome. A, Severe compression of left
subclavian vein with arms up (arrows).
B, Left subclavian vein becomes widely
patent (arrows) with arms down; no
evidence of thrombosis.
FIGURE 139 A, Coronal maximumintensity projection (MIP) image. B,
Posterior aspect of three-dimensional
volume-rendered (3D-VR) image
shows pulmonary arteries, left atrium
and pulmonary veins, and separate
opening of right middle lobe vein to
left atrium (arrow).
FIGURE 1310 A, Coronal multiplanar
reconstructed (MPR) image shows
embolic filling defects in right lower
lobe pulmonary artery branches
(arrows). B, Coronal maximum-
intensity projection (MIP) image
shows whole branching pattern of
pulmonary arteries but hides details.
Embolic filling defects in right lower
lobe pulmonary artery cannot be
seen clearly.
AB
AB
FIGURE 1311 Contrast-enhanced magnetic resonance angiography (CE-MRA) of coronary arteries shows (A) normal origin of the left system (arrows)
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and (B) right coronary artery (arrow).
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AB C
FIGURE 1312 A-C, Abdominal aorta and bilateral lower-extremity runoff. Maximum-intensity projection (MIP) images show fusiform ectasia of infrarenal abdominal
aorta (arrow), mild ectasia of distal external iliac artery and proximal common femoral artery (CFA) (short arrows), short-segment moderate to severe stenosis in left
popliteal artery (thick arrow), and collateral vascularization. Normal three-vessel runoff is seen in each calf.
penetrating atherosclerotic ulcers.30 Black-blood MRA sequences
are rarely used in current runoff protocols, largely because of long
acquisition times.
The standard MR runoff uses 3D CE-MRA
6,31
for accurate and
detailed assessment of the peripheral arteries. A recent meta-analysis
of 32 studies from 1998 to 2009 shows a pooled sensitivity of 94.7%
and specificity of 95.6% for diagnosing segmental steno- occlusive
lesions in peripheral arteries.32 The fundamental challenge in
peripheral CE-MRA is balancing accurate imaging throughout
the length of the vascular tree against the imaging capabilities of
the system. In general, the craniocaudal FOV requires acquisition
from the juxtarenal abdominal aorta to the foot in three or four
overlapping stages. In one approach, the timing of the gadolinium
bolus is optimized for the superior station (abdomen and pelvis),
then imaging is performed as rapidly as possible to keep up with
the flow of contrast material down the distal arteries. Image quality
in the first stage is excellent but often suboptimal in the third stage
as gadolinium enters the venous system, with resulting venous contamination of the image. This is especially true in patients with a
short arteriovenous transit time, such as those with severely ischemic limbs, where precise definition of the tibial arteries is critical.
On average, contrast reaches the common femoral artery (CFA)
in 24 seconds, with only an additional 5 and 7 seconds needed to
reach the popliteal artery and ankle, respectively.
33
Contrast travel
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time to the femoral arteries correlates with increasing age, male
gender, history of myocardial infarction (MI), and diabetes, and is
increased in the presence of aortic aneurysm. So-called moving
table technology can be used to chase a single bolus of contrast
agent in its distal progression.
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Goals of peripheral MRA are higher spatial resolution to bet-
ter visualize smaller distal vessels, and faster scanning to lessen
13
the negative impact of venous enhancement. Newer acquisitions
and 3-tesla (3 T) scanners provide technological advances. Parallel
imaging with multichannel phased-array coils are used to reduce
imaging time.35 Full-length dedicated peripheral multichannel vascular surface coils improve signal. Time-resolved acquisitions can
be used in standard protocols and may be particularly useful in
the calves. To reduce venous contamination, subsystolic midfemoral venous compression can be applied.
Hybrid injection protocols overcome some technical limitations and are more accurate for evaluating the popliteal trifurcation and foot vessels.
37,38
TOF sequences are obtained to optimize prescription of the 3D
slabs. The first injection is used to acquire high–spatial resolution
MRA of the calf and foot to minimize venous contamination; 3D
time-resolved MRA for this stage can eliminate the need for bolus
timing and decrease the total contrast load. The second injection
is used for acquisition of both the aortoiliac and femoral station.
Complementary TOF sequences are used to assess the ankle and
foot. A typical dose is 0.2 mmol/kg of gadolinium-based contrast
administered at a flow rate of 1.5 to 2 mL/sec, followed by 20 mL
of saline. Accurate synchronization of the peak contrast material
in the vascular bed and central k-space acquisition is essential for
high image quality. Timing can include a test bolus or bolus tracking. For patients with asymmetrical flow to the legs, optimal arterial opacification in the more symptomatic leg (i.e., slower flow)
can be challenging. Time-resolved sequences can determine peak
arterial and venous enhancement of both legs so timing can be
adjusted for the more symptomatic leg.
Magnetic resonance angiography can also be used to evaluate
patients after endovascular intervention.
gery, CE-MRA can evaluate graft location, patency, and stenosis of
the proximal and distal anastomosis, even for small distal grafts.
However, magnetic susceptibility created by metallic clips is problematic even when source images are used for the evaluation.
34
36
Initial precontrast low-resolution axial 2D
31
39
Following bypass sur-
Blood pool contrast agents show promise to decrease gadolinium doses and provide a much longer time window for data
acquisition, based on prolonged relaxivity in comparison to conventional gadolinium agents.
loss from less pronounced T1 shortening are some challenges in
blood pool MRA.
31
Newer noncontrast MRA techniques that use
acquisitions in systole and diastole to produce contrast
40
Venous contamination and SNR
41
are promising for runoff exams in patients with impaired renal function.
Dedicated evaluation of the pedal arteries (
rable to selective DSA.
42
Fig. 13-13) is compa-
Magnetic resonance angiography is used to evaluate patients
with clinically suspected popliteal artery entrapment syndrome
(
Fig. 13-14) and cystic adventitial disease. Popliteal artery entrap-
ment is an uncommon peripheral arterial disorder resulting from
an anomalous relationship between the popliteal artery and the
medial head of the gastrocnemius muscle. Magnetic resonance
imaging defines the anatomical relationships, and MRA allows
accurate evaluation of vascular compromise during provocative
plantar flexion and at rest.
43,44
Cystic adventitial disease accounts
for 1 in 1200 cases of calf claudication. A mucin-containing cyst
in the popliteal artery wall compromises arterial flow and causes
claudication. Water signal makes the cyst appear hyperintense on
T2-weighted images, and MRA reveals popliteal artery stenosis.
43,45
Upper-extremity vascular disease affecting the subclavian artery
includes stenosis, aneurysm, or compression due to thoracic outlet
syndrome. Imaging of the forearm and hand may be indicated to
evaluate vasculitis or ischemia secondary to trauma (
spatial resolution of MRA is inferior to DSA, although it is useful as
a noninvasive technique.
46
The acquisition window is restricted to
Fig. 13-15). The
the few seconds between full enhancement of the arteries and the
beginning of venous contamination. Blood pressure cuff inflation
proximal to the imaged area can extend imaging time and enhance
image quality of the palmar, metacarpal, and digital arteries.
47
Abdominal Vessels
Both CT and MR provide excellent imaging of the abdominal aorta
and its branches. Magnetic resonance angiography is indicated to
evaluate renal artery stenosis (RAS), mesenteric artery disease, and
abdominal aortic aneurysm (AAA), dissection, or occlusion. Single
breath-hold CE-MRA permits high contrast between vessels and
A B
FIGURE 1313 A, Time of flight (TOF) image of normal pedal arteries. B, Contrast-enhanced magnetic resonance angiography (CE-MRA) maximum intensity
projection (MIP) reconstruction of pedal arteries in patient with cryoglobulinemia and small-vessel vasculitis. Arteries of pedal arch are occluded. Moderate venous
enhancement is present.
AB
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FIGURE 1314 A-B, Arterial-phase maximum-intensity projection (MIP) images of leg show left popliteal artery entrapment (arrows).
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A
FIGURE 1315 Contrast-enhanced magnetic resonance angiography (CE-MRA) of hand. A, Dominant ulnar supply to hand in patient with absent radial artery.
B, Radial aspect of superficial palmar branch, showing stenosis (hypothenar hammer syndrome).
surrounding organs. Technical advances such as time-resolved and
parallel imaging can be incorporated into clinical protocols. For
detailed spatial measurements, black-blood (e.g., DIR) images are
optimal for measurement of the lumen and vessel diameter and
assessment of the aorta wall. Volumetric mask imaging will ensure
that the 3D volume is appropriately placed. After contrast injection,
at least two data sets (arterial and delayed phase) are acquired.
This strategy does not significantly prolong the study and can
provide valuable information, especially regarding venous structures. It can also be very useful for slow flow in large aneurysms,
B
or imaging a false lumen where the initial acquisition does not
provide adequate enhancement. Contrast doses of 20 mL, administered at 2 mL/s, are usually sufficient.
RENAL ARTERY IMAGING
The most common cause of RAS is atherosclerosis, which often
involves the ostia or proximal 1 to 2 cm of the renal arteries.
Fibromuscular dysplasia is the second most common cause of RAS
and typically affects the distal two thirds of the main renal artery.
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Contrast-enhanced MR is the modality of choice for patients with
hypertension and clinically suspected RAS.48 Coronal imaging is prescribed to minimize acquisition time (i.e., fewer phase- encoding
steps). Parallel imaging can be used to minimize craniocaudal
motion in the distal renal arteries.
that dense calcification causes CT artifacts that obscure the lumen and
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cause overestimation of stenosis severity. Calcium deposits accumu-
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late at or near the ostium where stenosis detection is critical. Threedimensional CE-MRA with subtracted MIPs has less artifact at the
ostium, and PC techniques can add information regarding hemodynamic significance. Secondary findings such as poststenotic dilation
and delayed renal parenchymal enhancement are also important.
Magnetic resonance angiography can be used for clinically suspected FMD, but the presence of alternating webs and dilation
may not be captured by the spatial resolution of MRA, particularly
in the distal renal arteries. Thus, a negative MRA cannot entirely
exclude the diagnosis.
ABDOMINAL AORTA IMAGING
Abdominal aortic aneurysms associated with atherosclerosis are
typically fusiform; a saccular configuration should raise the possibility of a mycotic aneurysm. Aneurysm evaluation includes the
proximal and distal extent of the aneurysm, as well as its relationship to visceral branch vessels. Three-dimensional MRA can identify the main and any supernumerary renal arteries (
mesenteric arteries.
Multidetector CT is the preferred modality for planning endovascular repair of AAAs and surveillance of stent grafts. Magnetic
resonance angiography does not image calcification.
resonance angiography is safe for nonferromagnetic stents and
does not induce heating or stent deflection.
Susceptibility artifact from stents limit postprocedural studies.
However, nitinol and PTFE devices have minimal MR artifact, and
early data suggest that MRA can be used in patients with nitinol
53
grafts.
Contrast-enhanced MRA is also accurate in the depiction
of endoleaks. Time-resolved MRA is also an attractive method to
characterize endoleaks because contrast passage into the aneurysm sac can be visualized as a cine loop.
ABDOMINAL AORTIC DISSECTION
Magnetic resonance angiography is used to detect propagation of
aortic dissection into the abdominal aorta. It can identify the proximal and distal flap as well as involvement of the visceral branches.
The celiac trunk and SMA usually arise from the true lumen, but
extension of the flap into the celiac trunk, thrombosis of the false
lumen, or compression of the true lumen can lead to hepatic or
49
The advantage of MRA over CT is
Fig. 13-16) and
51,52
54
50
Magnetic
splenic infarcts. Magnetic resonance angiography reliably depicts
the true and false lumen. For 3D acquisitions, postprocessing
enables selective viewing of branch vessels. Delayed imaging can
be used to characterize slow flow into the false lumen.
AORTIC OCCLUSION
Distal aortic occlusion is most commonly due to thromboembolic disease. Thrombus may be superimposed on severe atherosclerosis of the distal aorta and common iliac arteries. Magnetic
resonance angiography is used to evaluate not only the occlusion
but also the collateral circulation and distal reconstitution.
MESENTERIC ARTERIES
Chronic mesenteric ischemia (CMI) is most commonly a consequence of atherosclerosis in the proximal visceral arteries, but
can also be a sequela to dissection, median arcuate ligament syndrome (
Fig. 13-17), visceral artery dissection, vasculitides, and con-
nective tissue disorders.
Most patients do not develop symptoms of CMI unless two of
the three mesenteric arteries are occluded. Magnetic resonance
angiography is highly accurate for evaluating mesenteric origins,
where the majority of stenoses develop (
Fig. 13-18). High accuracy
is maintained to the level of second-order branches. Qualitative
and quantitative flow measurements with cine–phase contrast MRI
from the SMA and vein can be performed.
55
Patients who present with severe abdominal pain and clinical
suspicion for acute mesenteric ischemia require urgent imaging
because of the risk of irreversible bowel damage. Major causes of
acute mesenteric ischemia are SMA emboli (30%-50%), SMA thrombosis (15%-30%), acute mesenteric vein thrombosis (5%-10%),
and nonocclusive mesenteric vasoconstriction (20%-30%).56
Multidetector CT is typically used for initial imaging, since it has
more widespread availability, less motion artifact in patients who
are acutely ill, and the risk of bowel ischemia/infarction outweighs
potential concerns for iodine-induced nephrotoxicity. However, in
patients who do not require immediate intervention, MRA can be
used for follow-up to characterize chronic atherosclerosis, mesenteric occlusion, aneurysm formation, and vasculitis. Characteristics
of vasculitis include findings of wall thickening and increased gadolinium enhancement (
Fig. 13-19).
Transplantation
Magnetic resonance angiography is used in pre- and postoperative
transplant patients. Detailed knowledge of vascular anatomy is
essential to ensure safe and successful transplantation surgery.
FIGURE 1316 A, Coronal maximum-
intensity projection (MIP) image. B, Threedimensional volume-rendered (3D-VR)
images show bilateral accessory inferior
renal artery originating from left common
iliac artery (CIA) (arrows).
AB
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AB
FIGURE 1317 Median arcuate ligament syndrome. A, Sagittal maximum-
intensity projection (MIP). B, Three-dimensional volume-rendered (3D-VR)
images obtained from arterial phase of contrast-enhanced magnetic resonance
angiography (CE-MRA) show stenosis due to median arcuate ligament
compression in origin of celiac trunk (arrow).
Magnetic resonance angiography is used in presurgical evaluation
of the recipient and living donors
57,58
and in follow-up of patients
after transplantation of the liver, kidney (Fig. 13-20), or pancreas,
particularly in cases of suspected vascular complications.
In living donor liver transplantation, MRA provides a complete evaluation of the hepatic vascular anatomy in the presurgical phase. It provides information regarding biliary anatomy and
assessment of hepatic parenchyma for diffuse and focal abnormal-
59
ities.
Magnetic resonance angiography has high sensitivity and
excellent negative predictive value for detection of clinically significant vascular stenosis in liver transplantation.
60
After renal transplantation, MRA can be used for suspected vascular complications to identify patients who would benefit from
angioplasty.
and venous complications.
muscle perforator arteries can also be obtained for preoperative
planning of breast reconstruction.
61
In pancreas transplantation, MRA identifies arterial
62
Accurate maps of rectus and gluteal
63
Inflammatory Diseases of the Arterial Wall
Magnetic resonance imaging is the primary technology for diagnosis and follow-up of patients with large vessel vasculitis, based on
identification of vessel wall edema and thickening that can be seen
before lumen changes. Black-blood DIR imaging is preferred for
wall morphology, and postcontrast imaging can be used to demonstrate mural enhancement. Other wall abnormalities seen in vasculitis
include ulceration, dissection, stenosis, occlusion, and aneurysm.
FIGURE 1318 Sagittal maximum-intensity projection (MIP) image
shows severe stenosis of superior mesenteric artery (SMA) (arrow).
A
B
FIGURE 1319 Axial precontrast (A) and postcontrast (B) T1-weighted
images show aneurysmatic dilation, thickening, and contrast enhancement
of aortic arch, consistent with aortitis (arrows) in patient with Takayasu's
arteritis.
Takayasu's arteritis is an inflammatory disease that typically
affects young women, and early diagnosis can be difficult because
of its nonspecific symptoms and serological markers. Diagnosis
and identification of disease activity with MRA is important to
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FIGURE 1322 Giant cell arteritis (GCA). Both subclavian arteries have
smooth, tapered stenoses in mid- to distal segments.
FIGURE 1320 Oblique coronal maximum-intensity projection (MIP)
reconstruction shows patency of renal artery anastomosis of transplanted
kidney.
FIGURE 1321 Coronal maximum-intensity projection (MIP) image
shows occlusion of distal abdominal aorta in region of bifurcation (arrow),
intrahepatic inferior vena cava (IVC) thrombosis (short arrows), and
occlusion of bilateral common iliac vein, with extensive lumbar, epigastric,
and azygos collateral veins in same patient.
guide adequate therapy because severe stenoses, occlusion, or
aneurysm are late irreversible manifestations. MRA findings suggestive of Takayasu's arteritis include stenoses of the aorta and
its major branches (
Fig. 13-21). Involvement of the pulmonary
arteries is seen in 70% of patients and increases diagnostic confidence.
64
Biomarkers are less reliable, whereas MRA shows early
changes and evaluates disease activity. Findings include arterial
wall thickening and enhancement in the active phase, mural
thrombi, fusiform vascular dilations, and multifocal stenosis, and
then thickened aortic valvular cusps in the chronic phase.
65
Giant cell arteritis (GCA) is a large-vessel inflammatory disease affecting primarily older patients. Magnetic resonance
angiography is used to diagnose associated thoracic aortic
aneurysms and evaluates involvement of large peripheral arteries such as the subclavian arteries (
Fig. 13-22).
Magnetic Resonance Venography
Magnetic resonance venography (MRV) protocols differ from arterial imaging because of the differences in flow and disease patterns. As with arterial studies, noncontrast MRI such as TOF has
been largely replaced with CE-MRV, even though 2D TOF can cover
large volumes and detect slow flow.
The problems of flow-based techniques and the relatively long
acquisition times are overcome by the rapid 3D sequences used
for arteriography. Subtraction data sets can limit signal from arteries to produce high-quality venograms.
Thrombus has relatively high T1 signal from the formation
of methemoglobin. Blood products have characteristic MR signal changes that are used in the evaluation of very early to
late hemorrhage.
67
Inflammatory changes from acute deep vein
thrombosis (DVT) are characteristic. After contrast enhancement, mural enhancement of the vessel wall is seen around an
acutely thrombosed vein, appearing as a bull's eye. In conjunction with the inflammatory changes and organization of the
thrombus, this finding helps differentiate acute from chronic
thrombosis.
Deep Vein Thrombosis
When the vein in question can be accessed by sonography, ultrasound is the first-line modality for DVT. Magnetic resonance venography is a second-line modality and used when ultrasound is limited
by patient body habitus, limited acoustic window, or for other reasons.
Gadolinium is typically used, and 3D sequences routinely identify
filling defects diagnostic for DVT (Fig. 13-23). There is no role for DSA
66
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FIGURE 1323 Axial (A-B) and
coronal (C) postcontrast venous
phase images show left common
iliac, external iliac, and common
femoral vein thromboses (arrows).
in diagnosis, although percutaneous access can be used for therapy.
Computed tomography veno graphy can also be performed. Many
early studies have established 2D TOF accuracy for thrombosis
68,69
in
the large central veins, although contrast is beneficial for better characterization of more superficial and perforating veins with slow flow
and retrograde flow.
70
Newer noncontrast MRA techniques have been
used for DVT, but their utility requires more comprehensive studies.
Magnetic resonance venography is also useful for patients with suspected renal vein thrombosis and can show enhancement of tumor
thrombus.
71
Delayed-phase MRA also provides an evaluation of the
inferior vena cava (IVC) and hepatic and portal veins.
Occlusive diseases of central thoracic veins (
Fig. 13-24) are
commonly seen in patients with malignancy or coagulopathy
or long-term use of central venous catheters for hemodialysis,
hyperalimentation, or chemotherapy. Magnetic resonance venography is very helpful for vascular mapping in patients who have
chronic venous occlusion but require central venous catheter
placement. Magnetic resonance venography is the best modality
for compression and occlusion of the abdomen and pelvis. The
IVC (
Fig. 13-25) and iliac veins, lymph nodes, tumors, and large
organs can be identified. Finally, MRV delineates congenital
venous anomalies and can be used to assess patency.
Vessel Wall Imaging
Sudden catastrophic adverse events such as stroke, MI, and limb
ischemia do not necessarily correlate with lumen stenosis and
may be better predicted by plaque characterization. Thus, vessel
FIGURE 1324 Coronal maximum-intensity projection (MIP) image
shows right subclavian vein thrombotic occlusion (arrows) and patent left
venous system.
FIGURE 1325 Abdominal magnetic resonance venography (MRV).
Coronal maximum-intensity projection (MIP) image; large hypointense filling
defect due to thrombosis seen in inferior vena cava (IVC) lumen (arrows).
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