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journal homepage: www.elsevier .com/locate/apme

Simultaneous PET-MRI e A one stop shopmulti-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, Indiab Sr. Manager Operation, Indraprastha Apollo Hospitals, Sarita Vihar, New Delhi, Indiac 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

* Corresponding author. Tel.: þ91 981107295E-mail address: drjena2002@yahoo.com (

Please cite this article in press as: Jena Ahope?, Apollo Medicine (2014), http://dx.

http://dx.doi.org/10.1016/j.apme.2014.07.0070976-0016/Copyright © 2014, Indraprastha M

Although the concept of hybrid imaging has been around for

many years, in last fewdecades it has transformed fromvisual

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 specificmetabolic 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.

2.A. Jena).

, et al., Simultaneous PEdoi.org/10.1016/j.apme.2

edical Corporation Ltd. A

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 prototypeWhole 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

CEmark and FDA approval for customer purchase in 2011. The

technique uniquely allows the PET component of PET-MRI to

acquire PET data during theWhole bodyMR imagingmaking 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

T-MRI e A one stop shop multi-modality imaging: Hype or a014.07.007

ll rights reserved.

a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1e22

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-

graphmCT-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 � 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-MRIsystemoffersa rangeofpotential benefits inoncologic,

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

registrationwhich 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 fromCT (versusMRI)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-

dalities inabacktoback imagingsession:effectivelydone in100

casesduring 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

Please cite this article in press as: Jena A, et al., Simultaneous PEhope?, Apollo Medicine (2014), http://dx.doi.org/10.1016/j.apme.2

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 andmonitoring

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

themetabolic information from PETwith 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 andwill have amajor role to play in the diagnosis of

coronary artery disease, detection of hibernatingmyocardium

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 fromCT 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.

T-MRI e A one stop shop multi-modality imaging: Hype or a014.07.007

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