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Simpósio PICMI - Outubro /2011. A Ressonância Magnética como um método de aferição da PIC Alberto Tannús CIERMag – IFSC - USP. Major items of this talk:. Basic ideas for verifying ICP; MRI methodologies; Existing facility. Changes in morphology: - PowerPoint PPT Presentation
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Simpósio PICMI - Outubro/2011Simpósio PICMI - Outubro/2011
A Ressonância Magnética como um método de aferição da PIC
Alberto Tannús
CIERMag – IFSC - USP
Simpósio PICMI - Outubro/2011
Major items of this talk:
Basic ideas for verifying ICP; MRI methodologies; Existing facility
Simpósio PICMI - Outubro/2011
Changes in morphology:• An increased ICP would show as enlarged ventricles,
which can be seen in the transverse sectioning;• Optic Nerve Sheath Diameter (ONSD) – US -> MRI:
Increased ICP is transmitted through the cerebrospinal fluid surrounding the optic nerve, causing distention of the optic nerve sheath diameter (http://noninvasiveicp.com/node/47)
• retro-bulbar optic nerve sheath diameter (ONSD) above 5.82mm predicts raised ICP in 90% of cases (http://www.sciencedaily.com/releases/2008/09/080910210531.htm)
Simpósio PICMI - Outubro/2011
From Geeraerts T et al., Crit Care. 2008;12(5):R114
Simpósio PICMI - Outubro/2011
Changes in morphology continued:• Measurement of intracranial compliance (ICC) with
dynamic magnetic resonance imaging (MRI) of blood and cerebrospinal fluid (CSF) flows to and from the brain (research of N J Alperin from University of Illinois at Chicago) ;
(Alperin et al Acta Neurochirurgica Supplementum, 2005, Volume 95, Part 4, 191-193)
• MR imaging of the optic nerves and pituitary gland provided important clues for the diagnosis of idiopathic intracranial hypertension and showed a return to normal appearance after normalization of CSF pressure
(Suzuki et al, AJNR Am J Neuroradiol 22:196–199, January 2001)
Simpósio PICMI - Outubro/2011
Flow and perfusion methods:• Cerebral Blood Flow and ICP: results demonstrated
that CBF values span over a much narrower range as compared with ICP. It means no correlation, due to self regulatory mechanism of TCBF. (Alperin et al, ib.)
• Gives rise to correlations of blood flow (velocity and profile) with TCBF;
(one of our proposals.)
Simpósio PICMI - Outubro/2011
Major items of this talk:
Basic ideas for verifying ICP; MRI methodologies; Existing facility
Simpósio PICMI - Outubro/2011
Morphology:• Conventional imaging methods – RARE, TSE, IRSE etc.;• Fast Imaging methods – EPI;• Short TE methods – UTE, ZTE etc.;
Flow and diffusion:• Diffusion weighted imaging – DWI;• Image phase map for flow measurements;• Imaging methods for transverse velocity profile;• Spin Labeling for CBF and TCBF estimates – ASL, CASL,
PASL.
Simpósio PICMI - Outubro/2011
Major items of this talk:
Basic ideas for verifying ICP; MRI methodologies; Existing facility
Simpósio PICMI - Outubro/2011
CIERMag (Centro de Imagens e Espectroscopia in vivo por RM):• One 2.0 Tesla 31 cm horizontal magnet running with a
Bruker electronics (Avance III/ Paravision 5.1);• Capable to perform ANY MRI/MRS methodology;• MRI and MRS Probes for small rodents and small
primates (up to 450g), and for different nuclear species on demand;
• Pending conclusion of special facility to accommodate a 4.7 Tesla 33 cm bore horizontal magnet;
• Pending conclusion of the fully Digital MRI/MRS Spectrometer to operate this and other systems (ToRM 15 Project);
Simpósio PICMI - Outubro/2011
CITESC (Ciencia, Inovação e Tecnologia em Saúde, unidade de
São Carlos):• One 1.5 Tesla whole body scanner with patient/
volunteer agenda (clinical research);• One 1.5 Tesla (or one 0.35 Tesla) whole body scanner
for technological development (may be used for clinical experiments on new methodologies involving hardware development);
Simpósio PICMI - Outubro/2011
Probes: why focus on them? Diversity of anatomies – no single probe for all studies; Studies at the limit of sensitivity; Large number of nuclei of interest; Methodologies requiring dedicated hardware (e. g.
split transmit coil ASL – avoid MT); Flexibility of studies – would you touch a US$35k
probe to configure it for a new experiment? Better build your own!!
Simpósio PICMI - Outubro/2011
Tune & match circuit
“Double crosses” (outperforms) the equivalent Birdcage structure
Our best approach: Double Crossed Saddle
Simpósio PICMI - Outubro/2011
Latest developed probes:Receiving coils for rodents – surface coils
C
C C
CM
CT
RFout
Tune & match circuit on reception
Simpósio PICMI - Outubro/2011
Rodents brain surface coils*:
* Tested also as transmit/receive
Anesthetics mask
Motion restriction
Simpósio PICMI - Outubro/2011
Results: Double Crossed Saddle
Actually a 20/31 system for now
Simpósio PICMI - Outubro/2011
Thank you!