TUMOR IMAGING UPDATE | DR DEEPAK PATKAR | MR SPECTROSCOPY
Summary
TLDRThis talk delves into the transformative evolution of brain tumor imaging over the past decade, highlighting the shift from purely anatomical to advanced functional MRI techniques. It underscores the pivotal role of MRI in pre-surgical planning, treatment response assessment, and differentiation between true progression and pseudo-progression. The lecture explores the practical applications of MR spectroscopy and diffusion tensor imaging in distinguishing benign from malignant tumors, and their impact on surgical and therapeutic strategies. The speaker emphasizes the importance of an integrated, patient-centric approach to imaging, advocating for a shift towards value-based and outcome-focused radiology practices.
Takeaways
- 🧠 Brain tumor imaging has evolved significantly over the last decade and a half, shifting from purely anatomical to incorporating vascular, metabolic, and functional imaging techniques.
- 📈 The use of MRI in diagnosing brain tumors has progressed to include functional imaging, aiding neurosurgeons in planning surgeries with greater precision.
- 🔍 Advanced MRI techniques have enhanced the ability to assess treatment responses, differentiate between true progression and pseudo-progression, and discern true responses from pseudo-responses in patients undergoing chemotherapy or post-surgery treatments.
- 🌐 The conventional MRI sequences have been expanded to include advanced sequences like spectroscopy, diffusion, diffusion tensor imaging, and fusion imaging, providing more detailed insights into tumor characteristics.
- 🧪 MR spectroscopy plays a crucial role in distinguishing malignant from benign brain tumors by analyzing the ratios of various metabolites, aiding in the diagnosis of high-grade tumors and metastasis.
- 🔎 Diffusion and diffusion tensor imaging (DTI) help differentiate high-grade tumors from low-grade ones by measuring the restriction of water molecule movement within the tumor environment.
- 🏥 Practical clinical applications of advanced imaging include better surgical planning, understanding tumor infiltration versus deflection, and assessing white matter tract integrity for treatment strategies.
- 📊 The integration of conventional and advanced imaging techniques provides a comprehensive view of the tumor, aiding in the development of new treatment strategies and improving patient outcomes.
- 🤝 Interspecialty communication and coordination are emphasized as critical for effective patient treatment, highlighting the importance of radiology's role in the patient care continuum.
- 🌟 The future of radiology is envisioned to be both image-centric and patient-centric, with a shift towards value-based imaging and outcome-focused reporting, underlining the need for training future generations in these advanced techniques and values.
Q & A
How has brain tumor imaging evolved over the last decade?
-Brain tumor imaging has evolved from pure anatomical imaging to include vascular, metabolic, and functional imaging. This shift has enabled more sophisticated surgical planning and better assessment of treatment responses.
What is the role of MRI in current brain tumor imaging?
-MRI plays a crucial role in brain tumor imaging by providing functional imaging capabilities. It allows for the differentiation of true progression from pseudo-progression and true response from pseudo-response, thus aiding in better understanding of tumor behavior.
How does functional MRI benefit neurosurgeons?
-Functional MRI benefits neurosurgeons by enabling them to plan surgeries in a more sophisticated manner, assess treatment responses, and differentiate between different types of tumor progression and responses.
What are the newer MRI sequences that have been introduced for brain tumor imaging?
-Newer MRI sequences include spectroscopy, diffusion imaging, diffusion tensor imaging, perfusion imaging, arterial spin labeling, and fusion imaging. These sequences provide more detailed information about the tumor and its environment.
What is spectroscopy and how does it help in differentiating brain tumors?
-Spectroscopy is a technique that provides information about the chemical composition of tissues. It helps in differentiating malignant brain tumors from benign ones by analyzing the ratios of certain metabolites like choline, creatine, and lipids.
How does diffusion imaging contribute to the assessment of brain tumors?
-Diffusion imaging measures the movement of water molecules in tissues. It helps in identifying highly cellular tumors by showing restricted diffusion, which is indicative of areas with high viscosity or dense cell membranes.
What is diffusion tensor imaging (DTI) and its significance in brain tumor imaging?
-Diffusion tensor imaging is an extension of diffusion imaging that provides information about the structural connectivity and microscopic axonal organization of white matter tracks. It helps in localizing tumors in relation to these tracks and differentiating infiltration from deflection.
How can MRI spectroscopy differentiate between tumor recurrence and radiation necrosis?
-MRI spectroscopy can differentiate between tumor recurrence and radiation necrosis by analyzing the presence of certain metabolites. High choline levels indicate tumor recurrence, while low choline and high lipid peaks suggest radiation necrosis.
What are the practical clinical applications of DTI in brain tumor imaging?
-DTI has practical clinical applications such as track-specific localization of tumors, differentiating tumor infiltration from deflection, aiding in neurosurgical planning, and detecting white matter invasion by tumors.
How does the integration of conventional and advanced imaging techniques impact the understanding of brain tumors?
-The integration of conventional and advanced imaging techniques provides more detailed information about the underlying pathology of brain tumors. This aids in improving the understanding of brain tumors and helps in the development of new treatment strategies.
What is the importance of being both image-centric and patient-centric in radiology?
-Being both image-centric and patient-centric in radiology ensures that radiologists focus not only on the imaging details but also on the patient's overall treatment. This approach promotes interspecialty communication and coordination, leading to more value-based imaging and outcome-focused reporting.
Outlines
🧠 Evolution of Brain Tumor Imaging
The speaker outlines the significant advancements in brain tumor imaging over the past decade and a half, highlighting the transition from purely anatomical imaging to a more comprehensive approach that includes vascular, metabolic, and functional imaging. The role of MRI has evolved to enable neurosurgeons to plan surgeries with greater sophistication, assess treatment responses, and differentiate between true progression and pseudo-progression in patients undergoing chemotherapy or post-surgery treatments. The speaker emphasizes the importance of multiparametric MRI parameters in understanding tumor behavior and the shift from conventional sequences to advanced techniques like spectroscopy, diffusion, and perfusion imaging. The integration of functional and structural imaging provides a more complete picture, aiding medical teams in tumor grading, characterization, and localization, as well as in planning treatments and assessing responses.
🧪 Applications of MR Spectroscopy in Tumor Diagnosis
The speaker delves into the practical applications of MR spectroscopy in distinguishing between malignant and benign brain tumors. It discusses the use of specific metabolite ratios, such as choline, creatine, and lipids, to identify high-grade tumors and metastasis. The practical utility of MR spectroscopy is exemplified through its ability to differentiate between tumors and radiation necrosis, cystic tumors and abscesses, and various types of brain lesions. The speaker provides concrete examples of how spectroscopy can help in clinical settings, such as differentiating glioma from metastasis based on the presence of specific metabolites. The discussion also touches on the differentiation of lymphoma from other entities by the presence of a 'quin' peak sign and the identification of oligodendroglioma through its unique spectroscopic signature.
🔍 Role of Diffusion and Diffusion Tensor Imaging (DTI) in Tumor Characterization
The speaker explains the principles of diffusion and diffusion tensor imaging (DTI), which measure the free motion of water molecules in the brain's intra and extracellular compartments. These techniques are used to identify highly viscous or membrane-bound lesions, such as abscesses and highly cellular tumors, which exhibit restricted diffusion. The speaker references a 2006 article to discuss how diffusivity can differentiate high-grade tumors from low-grade ones. DTI's clinical applications include the localization of tumors in relation to white matter tracts, differentiation of tumor infiltration from deflection, and planning for neurosurgical procedures. The speaker provides examples of how DTI can be used to distinguish between different types of brain tumors based on the pattern of tract disruption or displacement, which is crucial for treatment planning and understanding tumor behavior.
Mindmap
Keywords
💡Brain Tumor Imaging
💡MRI (Magnetic Resonance Imaging)
💡Multiparametric Imaging
💡Functional Imaging
💡Spectroscopy
💡Diffusion Imaging
💡Diffusion Tensor Imaging (DTI)
💡Pseudo-progression
💡Perfusion Imaging
💡Fusion Imaging
💡Interspecialty Communication
Highlights
Imaging of brain tumors has evolved from pure anatomical imaging to vascular, metabolic, and functional imaging.
MRI's role has progressed from anatomical to functional imaging, aiding in sophisticated surgical planning.
MRI is effective in assessing treatment response, differentiating true progression from pseudo-progression.
Advances in brain tumor imaging have led to a better understanding of tumor behavior by medical professionals.
Conventional MRI sequences have been enhanced with new advanced sequences like spectroscopy, diffusion, and perfusion imaging.
Functional and structural imaging combined provides comprehensive information for medical teams.
New MRI sequences offer unique insights for tumor grading, characterization, and localization.
MR spectroscopy helps differentiate malignant from benign brain tumors based on metabolite ratios.
Practical applications of MR spectroscopy include distinguishing tumor types and complications like radiation necrosis.
Diffusion and diffusion tensor imaging (DTI) aid in differentiating high-grade tumors from low-grade ones.
DTI allows for track-specific localization of tumors and differentiation of infiltration from deflection.
Integration of conventional and advanced imaging techniques provides detailed pathology information.
Radiology must be both image-centric and patient-centric, focusing on interspecialty communication and coordination.
The future of radiology aims for value-based imaging and outcome-focused reporting.
The responsibility of training future radiologists includes advancing knowledge and emphasizing patient care values.
Transcripts
what i'll be doing in next 15 minutes
is talking about how imaging of brain
tumors
have changed over last decade also and
what is the current status
of role of mri including its
multiparametric parameters
in terms of the current status
there have been several advances in
brain tumor imaging over the last
decade decade and a half the
brain tumor imaging has changed
completely from
pure anatomical imaging to vascular
metabolic and functional imaging
use of mri as a diagnostic tool has
progressed from
completely anatomical imaging to
functional imaging
this allows neurosurgeons to plan
surgeries in a very sophisticated manner
it is effective in assessing treatment
response
when you are giving chemo or regulatory
post surgery
it differentiates true progression from
pseudo progression
and it also differentiates true response
from
pseudo response and this has allowed
the oncologist radiation oncologists and
surgeons
to understand the tumor behavior
much better it also allows a good
detection and assessment of
what is going to happen to the patient
in a much
sophisticated manner so the
routine conventional sequences in
human imaging in central nervous system
has moved from simple spin echo sequence
gradient echo sequence fast clinical
sequence inversion recovery sequence
flare sequence to a lot of new basic and
advanced sequences
in terms of a mass spectroscopy
diffusion
and diffusion tensor imaging or fusion
imaging
artillery spin leveling which is a part
of perfusion imaging without having
to inject contrast the true functional
imaging
which is bold imaging and fusion imaging
when these functional and structural
imaging
is combined together it gives
a complete information this allows
the medical oncologist surgical team
and radiation oncologist greater
insights into grading of humor
characterization of tumor functional and
anatomical localization of tumor
it also allows better understanding of
secondary effects on the adjoining white
matter tracks
helical cortexes etc it allows better
operating planning
response to treatment as i said solar
response or true response
and it allows much more accurate
information about
whether there is a recurrence of the
tumor or there are post
treatment changes so human protocol has
changed completely
from just a simple imaging to function
imaging and that's what we are going to
understand
in next 15 minutes so each of these new
sequences
provide very unique information which
when combined together
has implications for defining
the tumor type and grid better directing
biopsy
or surgical resection better planning
radiation and biological therapies
in a much accurate way it also assesses
the treatment response much earlier
quicker
and better than what we were doing
before and it also
allows the researchers understanding
mechanism of success and failure
of newer treatments typically
anti-angiogenesis therapy
so what are the newer sequences in
mri that allow this functional
information is better so you have
spectroscopy
difficult tension imaging perfusion
imaging arterial spring lending
functional mri and fusion imaging in
this part of the lecture we are going to
cover only spectroscopy
and diffusion and diffusion tensor
imaging and in the next part we are
going to cover
the other four sequences so let's start
with
understanding spectroscopy and
its role in differentiating malevolent
brain tumors
from benign ones there is a lot of data
available
across literature but what is by and
large followed
is this meta-analysis
covered by agnr in 2006
which talks about higher ratios of
coding upon creatine
with cutoff of two coding upon na
with cutoff of 2.2 and choline plus
gradient
upon mn and creating upon na
to decide that you are living with a
hygrid tumor
lower ratios of lipid upon lactate and
creatine upon lactate
is also considered as a patient
suffering from high grade tumor
metastasis can be differentiated from
hybrid lemons
by presence of high lipid gradient ratio
so what are the practical applications
of mr spectroscopy
it distinguishes abnormalities with same
imaging appearances and the examples are
differentiating tumor from radiation
necrosis
differentiating cystic tumor from
abscess differentiating metastasis
from astrocytoma or biomass
and differentiating toxoplasma from
lymphoma
when patient is immunocompromised and
here are actual examples
so these two morphologically
look quite similar although the size is
different
and it will be virtually impossible to
differentiate glioma
from metastasis then look at
spectroscopy so if we have
presence of mi and presence
of creatine that indicates
that you are dealing with drama also
in the peritumoric area what looks like
edema
if you have presence of choline that
indicates
your delay with an astrocytoma or
glycoma
metastasis on other hand will have
complete absence of intra-tumor
choline as well as intra-tumor
mi it will show lot of
lipid which will be absent in glioma so
that is the way to differentiate
glioma or primary tumors of brain
versus metastasis lymphoma can be
differentiated from these two entities
by presence of what is called as queen
peak sign
so when you have two top peaks of lipid
lactate
and choline you know you are dealing
with lymphoma oligodendroclima
on the other hand will have relatively
low cooling
high creatine and high in my
glycine so it's impossible to
differentiate glycine from
mi because both resonate
at the same location also if you
add the presence of tumor mainly in gray
matter
with infinite pattern you know you are
dealing with oligodendroplasma
and not astrocytoma or glioblastoma
radiation necrosis can be differentiated
from
recurrence of a tumor by
tall lip electric peak from 0.9
to 1.3 ppm with relatively
low cooling so when you have
post tumor bed evaluation
you want to differentiate recurrence of
a tumor from radiation necrosis
run a multivoxel spectroscopy
and look for in the tumor bed presence
of high choline
that would indicate presence of
recurrence
if across all the box cells there is
only
high level and nothing else you know you
are dealing with
radiation necrosis so relation necrosis
will have low cooling
high liquid tumor recurrence will have
high choline
and high choline in a ratio so that is
about
role of mr spectroscopy in
brain tumor imaging let's now move on
and see how diffusion and diffusion
tensor imaging
helps us in differentiating high grade
biomass
from road grid rhymers or any other
entities
how does diffusion work it is basically
an index of free motion
of water in the intra and extracellular
compartment
of the brain cells anything that has
high viscosity
or high membrane would impede motion and
then
will show a restricted diffusion so any
lesion with high similarity
so we are talking about hydrogen we have
restricted diffusion
anything that contains pus so we are
typically talking about abscess
which show restricted diffusion so
restricted diffusion will be seen in
abscesses
and highly cellular that means hydrate
tumors
based on this again the same article of
agnr in 2006
allows us to talk about differentiating
hybrid lamas
from low grade glamours by looking at
diffusivity
so hydrograms will show lot of
restricted
diffusion low grade lemons will show
facilitation of diffusion intermediate
grid glimmers will show
relatively less restricted diffusion
abscesses which show restricted
diffusion in the center
whereas if it was a cystic tumor the
solid component or peripheral component
of the cystic fibroid would show
restricted fusion
diffusion tensor imaging is an extension
of diffusion sequence a non-invasive way
of
understanding brain structural
connectivity it also allows us to look
at
microscopic axonal organization of white
metal tracks
and based on the directional rate of
diffusion of water molecules
we can see where the diffusion is
facilitated more
and where it is not so little bit of
more understanding
of diffusion tensor imaging
when we say that hydrogen atoms in
the entrance of the compartments are
flowing
at a rate of five centimeters per minute
that's not a complete proof
so along the white metal tracks the
water molecules
are moving at five centimeters per
minute
perpendicular to it the diffusivity is
virtually
zero and what we see in tumors and in
the region
is something in between so we calculate
fractional anisotropy
and look at how the diffusion is
so whenever diffusion is maximum you
will see
more restricted diffusion that is in
hybrid tumors
and when it is lesser you will see
facilitation of diffusion
that is called as fa and based
on the fractional anisotropy tracts
which are in transverse axis are labeled
as red
those superior interior are labeled as
blue and those enteroposterior are
labeled as green
and color used depends on the intensity
of fa what are the practical clinical
applications of dti
it allows track specific localization of
environmental
agents it allows localization of tumors
in relation to white metal tracts
it differentiates infiltration from
deflection and that is important
in grading the tumors it allows
localization of
male vitamin tracks for neurosurgical
planning
and it also detects awkward white matter
invasion
by hybrid life so based on the pattern
of dti you can actually decide
which tumor you are dealing with for
example
in gland mass and metastasis the tracks
will be displaced
whereas in anaplastic astrocytoma and
gbms
the tracks will be infiltrated but they
will remain
identifiable in very high grade
anabolistic astrocytomines and galliums
tracks will be completely disrupted
whereas in metastasis
and in edema the tracks will be normal
but just
displaced with slight change in the
color view and these are the actual
example this is a
left frontal lobe polygon
the tracks here are displaced but not
infiltrated
compare that with another quantum
learner which is a logarithmic again the
tracks are displaced
and not inverted compare these two
patients with this patient of
the one that i showed you before a
glioblastoma multiforme
in left temporal lobe the tracks are
completely
destroyed here is another example of the
net
in the left posterior frontal cortex the
tracks are displaced
color views are slightly changed but
there is no infiltration
so that is the importance of diffusion
and diffusion tension imaging
in advanced tumor imaging perfusion
attachment leveling functional mri and
fusion imaging will cover
in the next stop so to conclude this
part of the talk
with integration of conventional and
advanced imaging techniques we can
provide
increasingly detailed information about
the underlying pathology
these details will aid in improving our
understanding of brain tumors
and help in development of new treatment
strategies
in future what we also need to
understand
is radiology has to be both image
centric and patient-centric
we must understand that we are an
important
and an integral part of patient
treatment interspecialty communication
coordination is most important
and we must aim to change from volume
based to value-based imaging
from interpretation focus to outcome
focus reporting
and the responsibility of training our
future generation
with not only the advances but these
values lies with us
thank you for your attention
[Music]
you
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