prezantimi im në ecr 2014 '' molecular mri
DESCRIPTION
Molecular MRI ,TRANSCRIPT
Molecular MRI
F. NIKOLAS QEZI
MRI DEPT.
KENT & CANTERBURY HOSPITAL
EAST KENT HOSPITALS UNIVERSITY NHS FOUNDATION TRUST
ENGLAND / UK
Aim of study :What is molecular MRI ?
Molecular MRI is a special implementation of molecular imaging which allows the non-invasive visualization of the biological processes at the cellular and nano-molar level .
Modalities
PET-CT & SPECT
are the most sensitive modalities which have been the forefront in molecular imaging
In recent years molecular imaging has commanded attention beyond the field of nuclear medicine
New technologies
The advance of technology in medical imaging
has brought a new era of innovations.
Especially with the introduction of new state of art
scanners such as the :
Biograph mMR
which combines the spatial
resolution of MRI and the
metabolic sensitivity of PET
Usefulness / Versatility Molecular MRI is useful both in medical diagnostics and research
Medical diagnostics :
1. Improves the visualization in early detection of disease
2. Assist the therapy planning
3. Monitor / follow up the outcome
mMRI in Research
In Research mMRI is very effective to characterize :
1.Angiogenesis ( + / - )
2.Apoptosis ( programmed cell death )
3.Gene expression in living organisms
4.Facilitates the examination of cell migration
Methodology : Study
A recent study evaluates the mMR differentiation of VEGFR-2 levels ( vascular endothelial growth factor-receptor 2 ) in untreated gliomas in GL261 mouse model . The expression of VEGFR-2 levels was evaluated by using a anti-VEGFR2-albumin-Gd-DTPA probe with mMri
Treatment groups show different uptake of those levels in tumour region .
Results : Focusing on the study it confirmed that in vivo VEGFR-2 levels can be monitored as function of therapeutic evaluation .
Utilisation /advantages
The advantages that molecular MRI offers can be best utilised when we have the assistance of high sensitivity and cutting-edge equipment capable of quantitative measurements to detect probes that interact with targets
( contrast agents ) at the nano-molar level in vivo.
Contrast agents
Molecular MRI has proved effective in both cell tracking and detection of molecular process through the use of contrast agents comprised of micro-particles
of iron oxide ( MPIO ) - T2*-
MPIO ‘s provide high sensitivity contrast , owing to their potent super-paramagnetic properties.
Contrast agents are divided into two basic categories :
Negatives : reduction of T2 signal ( SPIO’s )
Positives : enhancing the T1 signal
( i.e. Lanthanide chelate /Gd-DTPA )
Nanoparticles
A category of substances that can act as novel contrast agents are nanoparticles which can be targeted with enhanced diagnostic specificity.
A special category of nanoparticles has also been designed to image dynamic studies / events and could be used in vitro as biosensors
Future role / Perspectives
The application of MRI in molecular imaging
is limited by its intrinsic low sensitivity.
A number of techniques have been developed to overcome this , which utilise a phenomenon termed ‘hyperpolarisation’.
Which is a change in membrane voltage
These techniques have been used
to image tissue pH , cellular necrosis
and to image the lungs.
Although most of the applications have been developed in animal models , they are increasingly being translated into human imaging
Results : Synopsis
Molecular MRI uses probes that can image :
o Biological / anatomical targets in vivo
o Dynamic events in vivo / in vitro
o Enzyme activity in vivo
o Multi–spectral imaging
References
A.Hengerer PhD & J Grimm MD : Molecular magnetic resonance imaging
Biomed imaging interv J. 2006 Apr-Jun, 2(2) : e8
Szatmari T. , Lumniczky K. , Desaknai S. , Trajecevski S. : Detailed characterisation of the mouse glioma 261 tumour model for experimental glioblastoma therapy 2006 Cancer Sci. Jun 97(6) : 546-53
Sosnovik DE. , Weissleder R. : Emerging concepts in molecular MRI ,
Curr Opin biotechnol. 2007 Feb 18(1) : 4-10 Epub 2006 Nov 28.
Gallagher FA . : Clin.Radiol.2010.Jul.65(7) 557-66 doi. 10.1016 / j.crad.2010.04.006
Patricia Coutinho de Souza , Krithika Balasubramanian , Nataliya Smith ,
Debra Saunders , Hong Chen et al. Oklahoma medical research foundation ,
Oklahoma city , USA : molecular MRI differentiation of VEGFR-2 levels on four different
experimental anti-glioma therapies within a GL261 mouse model
Margaret Bennewitz ; Cellular and molecular MRI approaches for cancer diagnosis
