Maximizing Time Resolved MRA for
Differentiation of Hemangiomas,
Vascular Malformations, and
Vascularized Tumors
Jane S. Kim MD, Linda Y. Kao MD, Ross
Borzykowski MD, Benjamin H. Taragin MD
Montefiore Medical Center
Bronx, NY
Goals and Objectives
• Provide background information on contrast-enhanced
Magnetic Resonance Angiography (MRA) using time resolved
imaging for vascular anomaly diagnosis
• Describe the technique used at our institution and
optimization of exam parameters
• Review key imaging features of hemangiomas and vascular
malformations in various modalities with special emphasis on
the TRICKS appearance
• Propose a diagnostic algorithm that relies heavily on the post
contrast T1 with fat saturation post TRICKS enhancement
appearance and the temporal TRICKS enhancement pattern
Introduction
• Misclassification of vascular anomalies remains common
despite fundamental pathologic differences
• An accurate distinction is important for management:
– Though most hemangiomas spontaneously resolve, approximately 1020% will warrant pharmacologic, surgical, or laser intervention
– Percutaneous sclerotherapy or more invasive transarterial
embolization is used to treat vascular malformations depending on
whether the lesion is high-flow or low-flow
Mulliken and Glowacki
Classification
Hemangiomas
Vascular Malformations
• characterized by a hypercellular
and rapidly proliferating phase
followed by an involuting phase
with diminished cellularity
• further sub-classified:
– Congenital hemangiomas
• Rapidly Involuting
Congenital Hemangiomas
(RICH)
• Non-Involuting Congenital
Hemangiomas (NICH)
– Infantile hemangiomas
• demonstrate normal cell turnover
rate, grow commensurate with
the body, and do not regress
spontaneously
• further sub-classified according to
type of vessel: capillary, arterial,
venous, lymphatic, or mixed
• may also be classified based on
presence of high-flow versus lowflow vessels, with those
containing arterial components
classified as high-flow
Vascular Anomaly Diagnosis
• Most often a clinical diagnosis
• Radiologic imaging provides a
role in challenging cases and
can be used to assess the
depth and extent of the lesion
http://www.adhb.govt.nz/newborn/teachingresources/dermatology/VascularLesions.htm
– Ultrasound: provides
excellent characterization of
superficial structures and
hemodynamics
– MRI: single best exam due to
its strong soft tissue contrast
and ability to define extent of
the lesion and involvement
with nearby structures
Contrast-Enhanced MR
Angiography
• Emerging as a reasonable alternative to conventional
diagnostic catheter angiography
• Advantages include lack of ionizing radiation and a lower
degree of invasiveness with its associated complications
• Can be technically challenging due to the variability of
contrast arrival in the distal extremities
Time-Resolved Imaging of Contrast
Kinetics (TRICKS, GE Healthcare)
• Algorithm samples lower spatial
frequencies (center of k-space)
more often than higher spatial
frequencies (periphery of kspace)
• Estimates missing data by linear
interpolation of values from
shared data across time frames
• Improves temporal resolution at
the expense of spatial resolution
– images that coincide with
contrast uptake in the area of
interest can be obtained with the
course of blood flow through
arterial, capillary, and venous
phases
Advantages of TRICKS over conventional
Contrast-Enhanced MR Angiography
• Elimination of a timing run with the contrast agent
– Allows use of a smaller dose of contrast material with all injected
contrast dedicated towards imaging
• Ability to cover a large region in pediatric patients allowing
comparison with the contralateral side
• In one study, TRICKS was shown to have faster in-room time
requirements (less than 30 minutes on average) than
angiography, venography, or duplex sonography
Our Technique
• IV line placed in the upper
extremity opposite to the lesion
being imaged to avoid injecting
an involved vein
• Both affected and unaffected
sides of the patient included in
the field of view for evaluation in
a single plane
• For distal upper extremity lesions,
the patient’s hands placed above
the head in a “superman”
position to avoid wraparound
artifact
• Any extension tubing must be
excluded from the field of view
3 month old with a left chest wall hemangioma
Coronal TRICKS image demonstrates an avid, homogenously
enhancing mass (arrow), initially visualized in phase 2 of 15,
concurrent with arterial vessels. Note the wraparound
artifact of the patient’s hands from improper positioning, and
the extension tubing from the patient’s intravenous line,
which may mimic a vessel (double arrows)
Contrast administration
• Standard gadolinium-based intravenous agents may be used
• Gadolinium based blood-pool contrast agent Gadofosveset
Trisodium (Ablavar – formerly Vasovist; Lantheus Medical
Imaging; North Billerica, MA) typically used (off-label) at our
institution in order to prolong the intravascular phase
• A saline flush is administered to clear the contrast from the IV
tubing (even more important in pediatric cases where a small
amount of contrast is used)
Image Acquisition
• Best performed in the coronal plane with post-processing in the
axial and sagittal planes
• Initial mask sequence obtained with initiation of scanning before
the injection of contrast in order to:
– capture early arterial information
– safeguard against contrast wastage in the event of scanner malfunction
• Typically perform 15 phases in our pediatric population, and up to
30 phases for peripheral lesions in our adult population to ensure
acquisition of the venous phase
• If the patient moves during the scan, we simply acquire another
mask sequence, re-inject the patient, and repeat the scan as the
original gadolinium will be subtracted from the second mask
sequence
Optimization of Temporal
Resolution
• Should be adjusted on a case-by-case basis
– Increasing temporal resolution allows better separation of the arterial
and venous phases
– Decreasing temporal resolution can be helpful in suspected peripheral
venous lesions, and in patients with slow peripheral flow such as those
with decreased cardiac output and bradycardia
• Temporal resolution can be increased by:
– Decreasing both the phase and frequency encoding steps (at the
expense of spatial resolution)
– Increasing the bandwidth (lowers signal-to-noise ratio)
– Decreasing the number of slices
Complete MR diagnostic exam
• Spin echo pre-contrast sequences utilized to accentuate flow voids in high
flow vessels
• Coronal and axial T1 sequences both provide fine anatomic detail of soft
tissue and bony involvement
• Axial T1 with FS sequence performed for comparison with a later postcontrast sequence
• Coronal T2 with and without FS and axial T2 with FS both aid in
characterization of lesion content
• Coronal gradient echo sequence detects blooming artifact, characteristic
of phleboli
• Contrast is injected with a minimum of 15 phases of TRICKS acquisition
followed by an axial T1 sequence with FS in order to visualize the
conventional post-contrast appearance of the lesion
Typical MR Imaging Protocol for
1.5-T Systems
Parameter
TR/TE (msec)
Coronal T1
Coronal T2 with
Coronal
Axial T1 with and
and without FS gradient echo
without FS*
Axial T2 with FS
TRICKS
475/20
4000/102
425/17
475/20
4000/102
5.9/2
Flip angle
(degrees)
-
-
20
-
-
45
Section thickness
(mm)
3
3
3
5
5
1.6
NEX
2
2
2
2
2
0.5
224 x 256
224 x 256
192 x 256
224 x 256
224 x 256
256 x 320
variable
variable
variable
15-24
15-24
480
24-30
24-30
24-30
40-50
40-50
30-40
300
240 / 270 (with
FS)
360
300-420 / 360-540
(with FS)
270
20sec x number
of phases
Matrix
FOV (mm)
No. of sections
Imaging time
(sec)
Note: FOV = Field of View, FS = Fat Saturation, NEX = Number of excitations, TE = echo time, TR = repetition time
*Postcontrast TRICKS images are obtained with the same sequence
Approach to Diagnosis
• Clinical history, US and MRI characteristics often helpful;
however, many entities demonstrate similar precontrast MR
characteristics
• Our algorithm relies heavily on the post contrast T1W FS
images and the TRICKS temporal enhancement pattern:
1.
2.
3.
Determination of avid, early arterial enhancement or minimal to
moderate arterial enhancement on T1W FS post contrast images
TRICKS temporal enhancement pattern
Other definable enhancement characteristics including dilated veins,
septations, and arteriovenous shunting
Can also help identify lesions that do not fit established criteria and
where tissue sampling may be indicated
Algorithm
Minimal to Moderate Enhancement
Central
Enhancement
Presence of
dilated veins
Venous
Malformation
Peripheral
Enhancement
Rim
Type
Macrocystic
LM
T1W with FS post TRICKS
Enhancement
TRICKS
Enhancement
Pattern
Heterogeneous
and septated
Microcystic LM
vs. Tumor with
Hemorrhage
Avid Enhancement
Early Arterial
Enhancement
Late Arterial/Venous
Enhancement
Presence of early
dilated draining veins
Yes
No
AVM
Hemangioma
Not definitely
a vascular
malformation
Hemangiomas
• Benign blood vessel tumors, theorized to have originated from
placental tissue embolized into the fetal circulation
• Most often found in the head and neck with clinical appearance
depending on the depth and phase of growth
• Further sub-classified into 2 subtypes:
– Congenital Hemangiomas: maximum growth at birth
• RICH: remarkable rate of regression after birth
• NICH: demonstrates growth to that of the child without regression
– Infantile Hemangiomas: most common tumor of infancy
• Undergoes proliferative phase of rapid growth until 8-12 months with variable rate
of regression over the next several years
• During involution, there is decreasing vascularity with fibrofatty
replacement
Hemangiomas: Imaging
• US:
• TRICKS:
– Well-circumscribed hyperechoic
and/or hypoechoic soft tissue mass
with color doppler flow
• MR:
–
–
–
–
Iso- or hypo-intense on T1W
Hyperintense on T2W
Flow voids due to high flow vessels
Fatty change during involution with
high T1 signal
– avid, homogenous, early arterial
enhancement without neovascularity
– should not demonstrate an early
draining vein
• Post TRICKS T1W with FS:
– uniform pattern of contrast
enhancement
Case 1: 2 year old female with a
left gluteal hemangioma
Spectral color doppler US image demonstrates a
well-defined heterogenous mass with arterial
waveform
Sagittal T1W with fat saturation post contrast
MR image demonstrates avid and homogenous
enhancement of the mass
Case 1: 2 year old female
with a left gluteal
hemangioma
Reconstructed image from a coronal
TRICKS acquisition shows avid, early
enhancement of the mass in phase 4
of 15, concurrent with arterial
enhancement and without evidence of
an early, dilated draining vein
Kaposiform
Hemangioendothelioma (KHE)
• aggressive, histologically distinct variant of hemangiomas with
an infiltrative growth pattern
• often complicated by the life-threatening Kasabach-Merritt
phenomenon, marked by profoundly decreased peripheral
blood platelets and fibrinogen due to platelet trapping and
spontaneous hemorrhage
• most commonly found in the midline of the trunk,
extremities, and retroperitoneum as an ill-defined, purpuric
mass
• Acquired tufted hemangiomas thought to be on the same
neoplastic spectrum as KHEs
Kaposiform
Hemangioendothelioma: Imaging
• US:
– Ill-defined soft tissue mass with
variable echogenicity
– Calcifications may be present
• MR:
– Poorly defined soft tissue
encapsulation involving multiple
tissue planes with skin thickening,
subcutaneous edema and stranding
– Signal voids may be related to
hemosiderin or fibrosis
– Destructive bony involvement is
common
• TRICKS:
– early arterial enhancement is
heterogenous and less avid than that
of a typical hemangioma
• Post TRICKS T1W with FS:
– surrounding enhancement in the
invaded and edematous soft tissues
Case 2: 3 month old female with thrombocytopenia
and leg swelling with a kaposiform
hemangioendothelioma
Axial T2W with fat saturation MR
demonstrates an ill-defined mass with
extensive surrounding soft tissue edema
(M = Marker capsule)
Coronal T1W with fat saturation post contrast
MR demonstrates avid, heterogenous
enhancement of the mass
Case 2: 3 month old
female with
thrombocytopenia and leg
swelling with a KHE
Coronal TRICKS MR image
demonstrates early enhancement in
phase 6 of 15, concurrent with arterial
enhancement of an ill-defined mass
from a dilated feeding vessel (arrow)
Venous Malformations
• most common type of vascular malformation, accounting for
one-half to two-thirds of all cases
• typically found in the head and neck region or extremities
• present as easily compressible soft tissue masses often
painful with venous engorgement
Venous Malformations: Imaging
• US:
– Mixed echogenicity with
compressible low-flow vessels
• CT:
– Phleboli may be present secondary to
slow flow and intralesional
thrombosis
• MR:
– Hypo- to isointense on T1W
(heterogeneity may indicate
hemorrhage or thrombosis)
– Hyperintense on T2W (low signal in
areas of septation or thrombosis)
– Signal voids on T2W and GRE
sequences secondary to phleboli
• TRICKS:
– delayed enhancement of the venous
spaces and tortuous vessels with the
absence of venous shunting
• Post TRICKS T1W with FS:
– complete enhancement with the
exception of signal voids related to
phleboli
Case 3: 15-year-old who presented with a
left neck venous malformation
Sagittal T2 with fat saturation MR image demonstrates
a hyperintense mass with multiple areas of low signal
abnormality representing phleboli
Sagittal T1W with fat saturation post contrast MR
reconstructed image demonstrates a centrally
enhancing mass
Case 3: 15-year-old who
presented with a left neck
venous malformation
Sagittal reconstruction from a coronal
acquisition TRICKS MR image shows
delayed enhancement in phase 9 of
15, concurrent with venous structures,
and the presence of dilated draining
veins (arrows)
Arteriovenous Malformations
(AVMs)
• comprise 10% of all vascular malformations
• often become symptomatic during puberty under the
influence of hormonal changes
• marked clinically as pulsatile, warm areas of superficial
blushing
• shunting may ultimately cause tissue ischemia, leading to pain
and ulceration of the skin
AVMs: Imaging
• US:
– high-flow vessels with low arterial
resistance and a higher venous peak
velocity than other vascular
malformations or hemangiomas
– arterialization of the draining veins
with pulsatile flow
• MR:
– Signal voids are typically present on
both T1W and T2W images with highflow vessels demonstrating high
signal on gradient echo
• TRICKS:
– early enhancement with early venous
shunting through the nidus with good
enhancement on first pass of the
feeding arteries and dilated draining
veins
– A steal phenomenon may be
observed with preferential flow to
the AVM, causing underdevelopment
and atrophy of nearby
musculoskeletal structures
• Post TRICKS T1 with FS:
– enhancing vascularity but no defined
soft tissue mass
Case 4: 12 week old female with a
right scapular AVM
Spectral color Doppler US image demonstrates a
waveform typical for low arterial resistance with
arterialization of the draining veins
Coronal T1 with fat saturation post contrast MR image
demonstrate avid enhancement of the lesion
Case 4: 12 week old
female with a right
scapular AVM
Coronal TRICKS MR image
demonstrates the presence of early,
dilated draining veins (arrows) which
enhance in phase 7 of 15, concurrent
with arterial vessels, indicating
arteriovenous shunting
Lymphatic Malformations (LMs)
• Composed of chylous fluid, lined by endothelium
• Further characterized as:
– Microcystic (cystic hygroma): numerous small cysts smaller than 2cm
– Macrocystic (lymphangioma): larger cysts of varying size
• Most are present at birth with 90% seen at 2 years
• Most common location is the head and neck with clinical
findings of rubbery and noncompressible
Lymphatic Malformations: Imaging
• US:
– Microcystic: ill-defined and
hyperechoic, due to the innumerable
interfaces produced by the tiny cysts
– Macrocystic: multiloculated cystic
lesions with vascular flow in the
septa
• MR:
– low signal on T1W and intense high
signal on T2W MR imaging due to
fluid content
– increased T1 signal and fluid/fluid
levels may be present due to
proteinaceous or hemorrhagic
content
– adjacent subcutaneous fat stranding
may be present secondary to
lymphedema
• TRICKS:
– may show enlarged feeding vessels or
enhancement of septations
– overwhelming majority and center of
the lesion will never enhance as
opposed to hemangiomas
– no early venous drainage
• Post TRICKS T1 with FS:
– Microcystic: typically no
enhancement
– Macrocystic: only rim or septal
enhancement
Case 5: 10 week old female with a
right chest wall macrocystic LM
Color Doppler US image demonstrates a complex cystic mass
(arrows) with no internal vascular flow
Axial T1W with fat saturation post contrast images
demonstrate a cystic mass with peripheral
enhancement (arrows) suggestive of superimposed
infection
Case 5: 10 week old
female with a right chest
wall macrocystic LM
Coronal TRICKS MR image shows
slightly enlarged intercostals arteries
and peripheral enhancement of the
lesion (arrow) in phase 11 of 35
Case 6: 22 year old female with a
right arm low grade sarcoma
Coronal T1W with fat saturation post contrast MR
images show an avidly enhancing soft tissue mass
(arrow)
Magnified coronal oblique reconstructed
image demonstrates findings suggestive of
neovascularity of the lesion
Case 6: 22 year old female
with a right arm low grade
sarcoma
Coronal TRICKS MR image
demonstrates enhancement of
tortuous, haphazardly arranged
vessels, suggestive of neovascularity in
phase 8 of 10 without evidence of
early arterial enhancement or
presence of a dilated draining vein
Case 7: 3-year-old who presented with neck
bulging when crying with ectasia of the left
internal jugular vein
Axial double inversion recovery image demonstrates a dilated left internal jugular vein
depicted as a flow void (arrow)
Case 7: 3-year-old who
presented with neck bulging
when crying with ectasia of
the left internal jugular vein
Coronal TRICKS MR image
demonstrates enhancement of the left
internal jugular vein (arrow) in phase 7
of 15
Conclusion
• Distinction between hemangiomas, vascular malformations
and other vascularized tumors important as they are managed
by different treatment regimens
• Time resolved contrast-enhanced MR Angiography has
become an increasingly important adjunct in the diagnosis of
vascular anomalies
• Optimization of the exam technique and familiarity of the
TRICKS imaging appearance is essential and can often assist in
accurate lesion characterization
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