I am not sure if you need the M0/calibration scan for all ASL
sequences. For 2D pulsed ASL sequences you need a calibration/M0 scan.
For some sequences, this is the first volume; for other sequences,
there is a separate scan. I am not sure about Philips or your
particular sequence.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
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On Fri, Aug 9, 2013 at 12:41 PM, Dorian P. <[log in to unmask]> wrote:
> Thank you.
>
> The smoothing flag in BASIL should be a good solution, I didn't notice it.
>
> At the moment I don't get a calibration image. Is it a setting in the
> sequence or a separate sequence? Any idea how to set it on a Philips
> scanner?
>
> Thank you.
>
>
> 2013/8/9 MCLAREN, Donald <[log in to unmask]>
>
>> In the research group that I work with, we smooth the calibration
>> image and used the smoothed calibration image in the CBF calculations.
>> Smoothing the calibration image can remove spikes in the signal of
>> individual voxels.
>>
>> Since the ASL images aren't smoothed, we then smooth the final CBF maps.
>>
>> One additional consideration is to smooth only within brain tissue,
>> rather than smoothing the entire image.
>>
>> Best Regards, Donald McLaren
>> =================
>> D.G. McLaren, Ph.D.
>> Research Fellow, Department of Neurology, Massachusetts General Hospital
>> and
>> Harvard Medical School
>> Postdoctoral Research Fellow, GRECC, Bedford VA
>> Website: http://www.martinos.org/~mclaren
>> Office: (773) 406-2464
>> =====================
>> This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
>> HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
>> intended only for the use of the individual or entity named above. If the
>> reader of the e-mail is not the intended recipient or the employee or
>> agent
>> responsible for delivering it to the intended recipient, you are hereby
>> notified that you are in possession of confidential and privileged
>> information. Any unauthorized use, disclosure, copying or the taking of
>> any
>> action in reliance on the contents of this information is strictly
>> prohibited and may be unlawful. If you have received this e-mail
>> unintentionally, please immediately notify the sender via telephone at
>> (773)
>> 406-2464 or email.
>>
>>
>> On Fri, Aug 9, 2013 at 4:12 AM, SG KIM <[log in to unmask]> wrote:
>> > Hi Dorian,
>> >
>> > I don't have experience in analyzing arterial spin labeling (ASL) data,
>> > but
>> > in general, VBM-like analyses and multiple comparison correction based
>> > on
>> > random field theory can be benefitted from an adequate amount (roughly
>> > expected size of signal) of spatial smoothing.
>> >
>> > FSL has (actually I didn't know before) a toolset for ASL data called
>> > BASIL
>> > (http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/BASIL) and it appears to have an
>> > adaptive smoothing function, so you may want to try it.
>> >
>> > Finally, it is never a good idea to smooth statistical maps. You should
>> > apply smoothing before computing statistics.
>> >
>> > Best,
>> > ---
>> > Seung-Goo KIM
>> >
>> > On 8, Aug, 2013, at 5:06 PM, Dorian P. wrote:
>> >
>> > Hello everybody,
>> >
>> > Is it advisable to smooth ASL data before analysis? Some other software
>> > advise to do so but I am not sure this is a good idea before analyzing.
>> >
>> > In case not, shall I smooth the results instead?
>> >
>> > Thank you
>> >
>> > Dorian
>> > TJU
>> >
>> >
>
>
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