Definiens in Medical Imaging
Definiens in Medical Imaging
Definiens in Medical Imaging
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4<br />
<strong>Def<strong>in</strong>iens</strong> <strong>in</strong> <strong>Medical</strong> Imag<strong>in</strong>g<br />
Computer Aided<br />
Detection<br />
“Automatic volumetry and segmentation allows reliable detection<br />
of tumor growth and has the potential to <strong>in</strong>crease<br />
reliability and significance of monitor<strong>in</strong>g growth <strong>in</strong> follow-up<br />
exam<strong>in</strong>ations.” 2<br />
International Journal of Computer-Assisted Radiology and Surgery<br />
Studies have shown that CAD systems aim to identify and volumetrically measure<br />
different types of tumors and polyps. They have proven to be as accurate as many<br />
tra<strong>in</strong>ed experts.<br />
In a colonography study reported <strong>in</strong> the American Journal of Roentgenology, experts<br />
concluded that a CAD system’s standalone performance exceeds human standards,<br />
and that it should be used synergistically with experts. 3<br />
Volumetric measurement<br />
Volumetric measurement is by far the most accurate way of measur<strong>in</strong>g tumor size<br />
which, <strong>in</strong> turn, is a key <strong>in</strong>dicator of whether the disease is respond<strong>in</strong>g to treatment,<br />
stabiliz<strong>in</strong>g or progress<strong>in</strong>g.<br />
A study <strong>in</strong> The Journal of Cl<strong>in</strong>ical Oncology compared RECIST predictions to accurate<br />
volumetric measurements. RECIST correctly predicted volumetric response or progression<br />
<strong>in</strong> 12 out of 17 cases; and <strong>in</strong> 3 of these 12 cases it needed one or two additional<br />
scan cycles.<br />
The delay identify<strong>in</strong>g cases where the tumor was progress<strong>in</strong>g was particularly<br />
noticeable: RECIST was only 50 per cent specific for progressive disease at the<br />
time that the progression was documented with volume. This means that 8 out of<br />
17 cases (just under 50 per cent) were not assessed as quickly as they might have been. 4<br />
Such delays may be vital to a patient’s chances of survival.<br />
Figure 3 Automatically detected and classified organs and lymph nodes <strong>in</strong> an axial view CT image<br />
2 ‘OncoTREAT: a software assistant for cancer therapy monitor<strong>in</strong>g’. Borneman, Lars, et al. Vol. 1 (5): pp231-242 (February 2007). Available at: www.spr<strong>in</strong>gerl<strong>in</strong>k.<br />
com/content/1518220748810553/.<br />
3 ‘Computer-Assisted Reader Software Versus Expert Reviewers for Polyp Detection On CT Colonography.’<br />
4 Jaffe, Carl C.Vol. 24 (20): pp3245-3251. July 10 2006. Available at: http://jco.ascopubs.org/cgi/content/abstract/ 24/20/3245
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