Aims and objectives
Computer-aided detection/diagnosis (CAD) is increasingly used in clinical practice.
CAD systems are useful for decision making in detection and interpretation of diseases by clinicians.
Therefore,
quality assurance (QA) for CAD has a key role in clinics and it helps end users to make aware of changes in CAD performance both due to intentional or unintentional causes.
However,
there are no QA requirements for CAD in clinical use at present.
Need of QA for CAD systems has identified and published by CAD subcommittee of American Association...
Methods and materials
Blurring of the CT image can be described by the PSF of a system [3,
4].
The PSF is assumed separable into a two-dimensional (2D) PSF in the x-y scan plane and the SSP in the z-direction perpendicular to the scan plane [5-8].
Then,
the three dimensional (3D) CT image I (x,
y,
z) can be expressed as [4,
6,
7].
I(x,y,z) = [O(x,y,z)**PSF(x,y)]*SSP(z) (1)
where O(x,
y,
z) is the object function,
PSF(x,
y) and SSP(z) are the 2D PSF and slice sensitivity profile,...
Results
Lung cancer CT screening CAD systems’ performance has assessed for screening images of two clinics and Figure 2 and 3 show sample CAD detections.
According to Figure 2,
only four nodules from each lung has detected by the CAD system on Plaka screening clinics’ images of the selected location.
Therefore,
one false negative detection appears in each left and right lungs and the detection rate is 80%.
Figure 3 shows that all five nodules on left lung have detected while four from the right lung....
Conclusion
Results indicate that QA of CAD will be required when changing the imaging system hardware/software components or image acquisition parameters.
Proposed QA protocol applies its own images of the CT scanner for QA process and more confidence results have obtained than applying different scanners’ images such as public databases’ images.
Furthermore nodule simulation is a solution for the burden of collecting larger number of nodules by an individual clinic.
Therefore,
additional cost and the time required to collect larger number of nodules can be reduced...
References
1.
Huo Z,
Summers RM,
Paquerault S,
Lo J,
Hoffmeister J,
Armato SG 3rd,
Freedman MT,
Lin J,
Lo SC,
Petrick N,
Sahiner B,
Fryd D,
Yoshida H,
Chan HP.
Quality assurance and training procedures for computer-aided detection and diagnosis systems in clinical use.
Med Phys.
2013 Jul;40(7):077001.
2.
Petrick N,
Sahiner B,
Armato SG 3rd,
Bert A,
Correale L,
Delsanto S,
Freedman MT,
Fryd D,
Gur D,
Hadjiiski L,
Huo Z,
Jiang Y,
Morra L,
Paquerault S,
Raykar V,
Samuelson F,
Summers RM,
Tourassi...