Patient‐specific estimation of spatially variant image noise for a pinhole cardiac<scp>SPECT</scp>camera

Cuddy-Walsh, Sarah G.; Wells, R. Glenn

doi:10.1002/mp.12883

Cited by 6 publications

(3 citation statements)

References 21 publications

(43 reference statements)

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“…With pinhole collimators, sensitivity is strongly distance-dependent, leading to highly variable system sensitivity across the FOV. 5,6 Measuring the counts acquired per MBq of a source in the cardiac system is valid, but only for that particular size, shape and location of source. To further complicate the comparison, sensitivity in clinical MPI also depends on the attenuation of the object.…”

Section: Effects On Count Sensitivity and Spatial Resolutionmentioning

confidence: 99%

Cardiac myocardial perfusion imaging with new SPECT cameras: Comparing apples and oranges

Wells

Ruddy

2020

Journal of Nuclear Cardiology

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See related article, pp. 1261-1269New SPECT cameras have been introduced in the last decade which are specifically designed for cardiac imaging. These cardiac SPECT cameras have improved sensitivity with maintained or improved spatial resolution 1 that has led to reduced acquisition times, lower patient doses, and enhanced image quality. Two of these new cameras are based on solid-state cadmium-zinctelluride (CZT) detectors. 2,3 Although they have improved performance for myocardial perfusion imaging, they also have certain limitations, such as a very restricted field-of-view in the case of the multiple pinhole system, which preclude use for general nuclear medicine applications. In an effort to bring some of the benefits seen with the cardiac systems to more generalpurpose protocols, a conventional dual-headed gamma camera design that employs CZT detectors with matched collimation was introduced. This multi-purpose CZT-based camera may still be used for cardiac imaging and so it is of interest then to see how its performance compares to the cardiac SPECT systems. Such a performance comparison was the aim of the study presented in this issue of the journal. 4 The authors present some excellent data, but care must be taken in its interpretation.

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Section: Effects On Count Sensitivity and Spatial Resolutionmentioning

confidence: 99%

Cardiac myocardial perfusion imaging with new SPECT cameras: Comparing apples and oranges

Wells

Ruddy

2020

Journal of Nuclear Cardiology

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“…It is well known that the level of noise and lesion detectability in a reconstructed image depends on reconstruction methods (algorithm, number of iterations, priors, resolution recovery, and filtering) in addition to the number of photons detected [8], [66], [92], [96]. While measuring myocardial photon counts in projection space is simpler to do, our approach includes the effects of reconstruction on the noise character of patient images.…”

Section: Discussionmentioning

confidence: 99%

“…The system sensitivity is additive, such that it may be lower for positions not seen by all detectors (outside the quality FOV) than for positions inside the QFOV. In the case of the DNM530c, even though the heart is positioned inside the QFOV, the positioning of the pinholes above and to the right of the FOV leads to a gradient in the number of photons contributing to an image across the length of the heart (from bottom-left to top-right in the QFOV) [33], [66].…”

Section: Collimator Sensitivity and Number Of Detectorsmentioning

confidence: 99%

Impact of Pinhole Collimation on SPECT Image Quality Metrics, and Methods for Patient-Specific Assessment of Noise and Standardization of Imaging Protocols

Cuddy-Walsh¹

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Dedicated cardiac pinhole SPECT camera designs offer improvements in overall sensitivity, thereby enabling the use of lower injected radiotracer activity and shorter imaging times than parallel-hole designs. The effect of these novel camera designs on image noise on a voxel-by voxel level has not previously been investigated. This work identifies position and orientation-dependent variability of spatial resolution in the fieldof-view (FOV) of pinhole cameras. It also identifies a 1.7-fold gradient in the magnitude of image noise across the length of the heart which leads to a 1.3-fold gradient in standard deviation values for a normal database for attenuation corrected images acquired with a commercially available cardiac pinhole camera. This pattern of noise varies with different patients and with different positioning of the heart within the FOV. Thus, to assist with clinical interpretation, a new 1-minute post-processing technique is developed to provide a patient-specific image of the noise distribution which may augment normal database information. Changes in attenuation result in varying levels of noise between patients of different body habitus administered the same radiotracer activity. A method for creating weight-based protocols is developed that standardizes the average noise in cardiac perfusion images by tailoring the radiotracer activity and acquisition time to the body mass of each patient. Methods developed in this thesis allow for more patientspecific imaging protocols, thereby standardizing the image noise level and providing physicians with more information about the noise and spatial-resolution distribution to aide in image interpretation.• I bootstrapped (all) and reconstructed (most, see above) images• I performed all calculations, evaluation, and statistical analysis using Matlab • I wrote articles and abstracts, and I presented oral and poster presentations meetings or conferences (oral or poster).

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Patient-specific SPECT imaging protocols to standardize image noise

Cuddy-Walsh

Clackdoyle

Renaud

et al. 2021

Journal of Nuclear Cardiology

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Patient‐specific estimation of spatially variant image noise for a pinhole cardiacSPECTcamera

Abstract: The PV method provides a rapid estimate for spatially variant patient-specific image noise magnitude in a pinhole-collimated dedicated cardiac SPECT camera with a bias of -0.3% and better than 83% precision.

Cited by 6 publications

References 21 publications

Cardiac myocardial perfusion imaging with new SPECT cameras: Comparing apples and oranges

Cardiac myocardial perfusion imaging with new SPECT cameras: Comparing apples and oranges

Impact of Pinhole Collimation on SPECT Image Quality Metrics, and Methods for Patient-Specific Assessment of Noise and Standardization of Imaging Protocols

Patient-specific SPECT imaging protocols to standardize image noise

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