Although the concept of hybrid imaging has been around for many years, in last few decades it has transformed from visual comparison of anatomical and functional images to software based image fusion, and currently integrated imaging systems have become the standard of care. The concept of PET-CT (Positron emission tomography-Computerized tomography) was introduced by David Townsend in 1998 and a decade after its prototype introduction; PET-CT has become the modality-of-choice for variety of clinical indications in oncology.

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2. Simultaneous PET-MRI e A one stop shop
multi-modality imaging: Hype or a hope?
Amarnath Jena a,*
, Sangeeta Taneja a
, Gaurav Katiyal b
, Nipun Choudhry c
a
Sr. Consultant, Nuclear Medicine, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi, India
b
Sr. Manager Operation, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi, India
c
Dy. Chief Medical Administrator (Academics), Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi 110076,
India
a r t i c l e i n f o
Article history:
Received 23 May 2014
Accepted 28 June 2014
Available online xxx
Keywords:
PET
Mutiple myeloma
Gynaecological malignancy
Although the concept of hybrid imaging has been around for
many years, in last few decades it has transformed from visual
comparison of anatomical and functional images to software
based image fusion, and currently integrated imaging systems
have become the standard of care. The concept of PET-CT
(Positron emission tomography-Computerized tomography)
was introduced by David Townsend in 1998 and a decade after
its prototype introduction; PET-CT has become the modality-
of-choice for variety of clinical indications in oncology.
The idea of integrating PET with MRI into a single imaging
platform has grown in the recent years due to the power of
MRI for tissue characterization, microstructural appraisal and
functional assessment, together with new PET tracers
designed to target specific metabolic processes, now catalyzed
by the clinical success of integrated PET-CT scanners, new
photodetector technologies for PET, the growth of the field of
bio molecular imaging and an increasing appreciation for the
power of multimodality whole body imaging, simultaneous
PET-MRI system has finally started to find its feet in the clin-
ical setting.
THE TECHNOLOGY: In fact putting “PET electronics” inside
a high field 3T magnet system and made to work with no
interference on their individual function whatsoever is a
technological marvel in the present era and a big potential
boost to patient management. The avalanche photodiode is
the heart of this development and the successful clinical use
of the prototype Whole body Simultaneous PET-MRI. Virtually
it combines the capability of both super powers in medical
imaging, each one having their roles well established in clin-
ical routine. It is apt to conceptualize the power of the com-
bed. Fully integrated Whole body and Simultaneous
acquisition PET-MRI system, provided by Siemens, received a
CE mark and FDA approval for customer purchase in 2011. The
technique uniquely allows the PET component of PET-MRI to
acquire PET data during the Whole body MR imaging making it
a single study, single session. Unlike this, the PET and MRI
fusion imaging is possible by getting the PET images from a
PET-CT study and fusing it off line with Whole body MR im-
ages done elsewhere as a separate study. Accuracy of result,
examination time, double scheduling and ownership of
* Corresponding author. Tel.: þ91 9811072952.
E-mail address: drjena2002@yahoo.com (A. Jena).
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: www.elsevier.com/locate/apme
a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e2
Please cite this article in press as: Jena A, et al., Simultaneous PET-MRI e A one stop shop multi-modality imaging: Hype or a
hope?, Apollo Medicine (2014), http://dx.doi.org/10.1016/j.apme.2014.07.007
http://dx.doi.org/10.1016/j.apme.2014.07.007
0976-0016/Copyright © 2014, Indraprastha Medical Corporation Ltd. All rights reserved.

3. individual imaging in interpretation are bottle necks and need
to be understood while considering such an option either due
to availability or other concerns. Among some fifty facilities all
over the world that have since installed this new technology,
Indraprastha Apollo hospitals Delhi is the 14th unit and, as of
today the first and only clinical site in South Asia to have this
system.
THE PET SUITE representing the epitome of molecular
imaging services is a visionary concept of House of Di-
agnostics and Apollo management, where two of the most
advanced molecular imaging facilities in the present era viz.
PET-CT and PET-MRI are put under one roof. PET Suite is of-
fering diagnostic capabilities of highest standards through a
team of experienced Radiology and Nuclear Medicine spe-
cialists, imaging physicists, biomedical engineers, nurses and
technologists. The PET-CT is the new 128 slice OptisoHD Bio-
graph mCT-X from Siemens with technologies including Time
of Flight and High-Definition PET 21.8 cm Zl FOV ensuring fast
and precise images which enable precise measurements of
metabolic processes including the assessment of neurological
disease, cancerous tissue and cardiac blood flow. The Simul-
taneous PET-MRI (Biograph mMR) houses a 3T MRI (Trio), Tim
(102 Â 18) MQ gradient: 45 mT/m with Slew rate of 200 T/m/s,
and PET: LSO crystal with avalanche photodiode (APD), Z FOV
of 25.8 cm. Fully functional with (PET on) uninterfered func-
tioning of routine imaging and advanced MR applications:
proton MRS, DTI, fMRI, Perfusion (T1 DCE and T2*).
BENEFITS: The clinical availability of hybrid Simultaneous
PET-MRIsystemoffersarangeofpotential benefitsinoncologic,
neurological, and cardiovascular applications. Over the last 1
year 4 months, over 800 cases (perhaps the largest series
worldwide as on date) have been completed at this facility
spanning variety of disciplines. One obvious benefit of simul-
taneous acquisition that we observed is improved image
registration which allows optimal anatomic localization of PET
findings over MRI for confident reporting. Other advantages
include, shorter overall imaging time, the ability to simulta-
neously acquire many biologically relevant parameters
improving diagnosis & assessing changing physiological/
pathophysiological processes, and that too with zero radiation
dose as from CT (versus MRI) which is a special point of concern
particularly for pediatric, young reproductive age women pop-
ulation and cases requiring repeated follow ups requiring
assessment of treatment response. Moreover with availability
of PET-CT under the same roof, co relative and comparative
imaging is being undertaken especially in cases such as lung
carcinoma where a high-resolution CT scan scores over MR,
providing comprehensive assessment and directing clinical
management. Also the unique facility has immensely contrib-
uted in defining the right and judicious use of the newly intro-
duced PET-MRI in the arena of clinical diagnosis through
comparative study with PET-CT on patients using both mo-
dalitiesinabacktobackimagingsession:effectivelydonein100
cases during standardization of PET-MRI in this first Indian site.
PET-MRI appears particularly useful in imaging patients
with dementia and Alzheimer's disease because the combi-
nation of high-resolution anatomical and perfusion MR in-
formation along with FDG or Pittsburgh Compound B (PiB) PET
during a single session can help us understand the patho-
genesis and mechanism of Alzheimer's disease, and enable
early diagnosis and drug development. It is also contributing
immensely for brain pathologies such as epilepsy. Brain
tumor evaluation that is now underway has been boosted
using multiparametric mapping capitalizing on the simulta-
neity of PET and MRI, hoping to provide a medical break-
through by noninvasively diagnosing areas of recurrence and
directing accurate site for biopsy/intervention and monitoring
treatment effect. Other area now getting established is the
standardization of MR based quantitation of PET indices using
brain PET-MR as a lone modality reliable for clinical workup
for dementia. Therapy planning in brain tumors by combining
the metabolic information from PET with BOLD (blood oxygen-
level dependence), fiber-tracking and diffusion weighted im-
aging in a single session is a leap forward with the existing
algorithms taking simultaneity of PET and MRI data available
in a single session.
For body oncology applications, simultaneous PET-MRI has
been found to provide panoramic view of whole body, excel-
lent tissue characterization, not possible with CT component
of PET-CT, along with targeted molecular whole body PET
imaging, proving unparalleled for head and neck carcinoma,
breast and liver cancers, neuroendocrine tumors, gynecolog-
ical cancer, prostate cancer and musculoskeletal tumors.
Many longitudinal studies with interrelated parameters like
glucose metabolism and neo-angiogenesis in cancer; plaque
biology in atherosclerosis; fibrocyte turnover in collagen dis-
ease under non oncology applications holds great promise
with the availability of magnitudes of tissue parameters
derived from molecular imaging (PET) and MRI.
The field of cardiology poised to greatly benefit from PET-
MR as the simultaneous acquisition allows accurate motion
correction and will have a major role to play in the diagnosis of
coronary artery disease, detection of hibernating myocardium
in patients with congestive heart failure, congenital heart
disease and precise estimation of ventricular volumes.
In our experience, the clinical performance of Simulta-
neous PET-MRI has been found to have a definite edge over
PET-CT for comprehensive disease assessment in oncology
practice viz; Head & Neck, Breast, Abdomen, Prostate, Multiple
Myeloma, Gynecological malignancy both in staging/restag-
ing/recurrence/therapy response settings, of course in many
cases with an added information on lung from CT chest that is
usually available as a preliminary test in cancer staging. It is
truly a single stop shop in neuro imaging especially in brain
cancer like glioma recurrence and neuro degenerative dis-
eases like dementia. In most of the other clinical situations
like infection evaluation, combined detection sensitivity of
PET and MRI is found making an impact as a fast and
comprehensive technique.
The various advancements being made in the field of Dis-
ease Specific Biological markers will further open newer ave-
nues and bring greater insights into the disease. The role of
PET/MRI in understanding the disease progression and
assessment is likely to hugely contribute to the Clinical
Management of our Patients.
Conflicts of interest
All authors have none to declare.
a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e22
Please cite this article in press as: Jena A, et al., Simultaneous PET-MRI e A one stop shop multi-modality imaging: Hype or a
hope?, Apollo Medicine (2014), http://dx.doi.org/10.1016/j.apme.2014.07.007

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