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Well stated Wayne...

Every echocardiography tech has had the experience of hearing a stenotic or 
regurgitant jet and struggled with displaying the associated spectral wave 
form.  One might argue that these hemodynamic conditions are clinically 
insignificant.  However, a tight carotid stenosis versus totally occluded 
carotid artery is markedly different from a diagnostic perspective.

Therefore, I too agree that omitting scrolling spectral Doppler display with 
audio from the DICOM capturing standard was a mistake.  If the vascular 
community is to embrace and broadly adopt DICOM PACS it's obvious the 
standard must change in this regard.   I'm surprised their voice of 
resistance has not resulted in change to date.

This said, the vascular community should plan on ECG triggering as part of 
their study protocol or the storage requirements imposed from capturing long 
clips versus shorter heart beat loops will cause resistance from those who 
manage storage economics.

Perhaps it could be made an option within the standard and also user 
selectable by application on the ultrasound system.  I can't imagine the 
ultrasound manufacturers would resist this as this represents software 
upgrade revenue from installed base users and a reason to buy new equipment 
if this change is implemented.

By addressing it as an option within the standard and user selectable by 
application... it allows those who are comfortable with frame Doppler 
captures to maintain their clinical use model while others who feel 
scrolling spectral Doppler displays with audio is a clinical necessity will 
adopt DICOM PACS.

This is a subject linked to diagnostic confidence and not a one size fits 
all issue and needs to be addressed by the DICOM committee.

Chris Walker @ CVS


----- Original Message ----- 
From: "Wayne Moore" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 17, 2006 7:46 AM
Subject: RE: [echocardiography] Re: Doppler audio and digital clips


> With all due respect, your comment lacks understanding of the role of 
> audio
> in concert with the spectral display. Variants in the tonal quality of a
> Doppler audio signal associated with mild to moderate lesions are often
> heard by the echocardiographer before a complete spectral waveform can be
> visualized (i.e., developed) on the display. Indeed, experienced echo 
> users
> use these tone variants to guide the fine positioning of the transducer to
> maximize the intensity and completeness of the spectral display. Anyone 
> who
> has experienced the challenge of obtaining a complete spectral waveform in
> cases of mild aortic insufficiency can attest to this. From an engineers
> perspective the question is one of dynamic range and the low energy 
> content
> resident in the higher frequencies (i.e., higher velocities). Due to the
> limited display dynamic range of monitors the wide range of returning
> Doppler signals must be significantly compressed in order to be displayed.
> Even with very generous logarithmic (log) compression the monitor cannot 
> go
> much beyond 40dB of displayed dynamic range, and more typically winds up
> nearer to 30dB. The audio detector - the human ear, is much better at
> hearing the low energy high frequencies, thus these signals are often 
> heard
> before they are seen. Modern ultrasound systems have controls that allow 
> the
> operator to "window" compress over the entire dynamic range of the
> ultrasound system. Once the flow variant is heard, the operator can select 
> a
> log compression that will bias the display toward that frequency range,
> where you then have your best chance to produce a complete spectral
> waveform. I would also take exception to the comment that manufacturers 
> have
> kept audio in the ultrasound systems merely as a "feature". A "feature" 
> that
> is not used by echocardiographers ceases to be a feature and instead 
> becomes
> engineering overhead both in the design phase as well as in the sustaining
> engineering phase. Hardly redundant, Doppler audio can be, and has proven 
> to
> be an extremely helpful tool in the hands of a careful echocardiographer.
>
> G. Wayne Moore, BSEE, MA
> President and CEO
> Sonora Medical Systems
> 1751 S. Fordham St Longmont, Colorado 80503
> (888) 476-6672
> Http:\\www.4sonora.com
>
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> you are not authorized to receive it, please promptly delete this message
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>
> Thank you
>
> -----Original Message-----
> From: [log in to unmask]
> [mailto:[log in to unmask]]On Behalf Of Dr. George Thomas
> Sent: Friday, April 14, 2006 11:57 PM
> To: [log in to unmask]
> Subject: [echocardiography] Re: Doppler audio and digital clips
>
> Dear Andy:
>
> I agree with you. Audio was used during the "blind" Doppler era, when
> spectral displays were not available. Now that the spectral displays
> are available, audio becomes redundant. However, manufacturers have
> retained this facility because they would not like to decrease
> the "features" of a machine. Have you tried audio in tissue Doppler
> mode? This can be used as a percussion instrument for a rock show!
>
> Dr. George Thomas
> Kochi, India
>
>
> --- In [log in to unmask], "Andrew Horning"
> <andrewhorning@...> wrote:
>>
>> Sonographers already/still do have the sound while they're
> obtaining the
>> study.  I've not yet heard a reading physician claim to need
> audio.  Is
>> audio playback a real need?  Technically, it's not difficult to
> acquire
>> and synchronize digital sound and clips.  Heck; we could digitally
>> acquire stethoscope sounds too, for that matter.
>> But the decision was made some time ago not to acquire digital audio
>> with ultrasound because this was deemed unnecessary.
>> Will a reading physician chime in?
>>
>> Andy Horning
>> The Freedom Farm
>> 7851 Pleasant Hill Road
>> Freedom, Indiana  47431
>>
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