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Quantitative analysis of small coronary artery calcium detectability with an accurate simulation and validation on a clinical CT scanner.
Severance, Lauren M; Pack, Jed D; Contijoch, Francisco J; McVeigh, Elliot R.
Afiliación
  • Severance LM; Department of Bioengineering, UC San Diego School of Engineering, La Jolla, California, USA.
  • Pack JD; Radiation Systems Lab, GE Global Research, Niskayuna, New York, USA.
  • Contijoch FJ; Department of Bioengineering, UC San Diego School of Engineering, La Jolla, California, USA.
  • McVeigh ER; Department of Radiology, UC San Diego School of Medicine, La Jolla, California, USA.
Med Phys ; 50(10): 6060-6070, 2023 Oct.
Article en En | MEDLINE | ID: mdl-37523236
ABSTRACT

BACKGROUND:

The absence of coronary artery calcium (CAC) measured via CT is associated with very favorable prognosis, and current guidelines recommend low-density lipoprotein cholesterol (LDL-c) lowering therapy for individuals with any CAC. This motivates early detection of small granules of CAC; however, calcium scan sensitivity for detecting very low levels of calcium has not been quantified.

PURPOSE:

In this work, the size limit of detectability of small calcium hydroxyapatite (CaHA) granules with clinical CAC scanning was assessed using validated simulations.

METHODS:

CT projections of digital 3D mathematical phantoms containing small CaHA granules were simulated analytically; images were reconstructed using a filter designed to reproduce the point spread function of a specific commercial scanner, and a relationship of HU number versus diameter was derived. These simulation results were validated with experimental measurements of HU versus diameter from phantoms containing small granules of CaHA on a GE Revolution CT scanner in the clinic; ground truth measurements of the CaHA granule diameters were obtained using a Zeiss Xradia 510 Versa high-resolution 3D micro-CT imaging system. Using experimental measurements on the clinical CT scanner, detectability was quantified with a detectability index (d') using a non-prewhitened matched filter. The effect of changes to reconstruction slice thickness and reconstruction kernel on granule detectability was evaluated.

RESULTS:

Under typical clinical calcium scanning and reconstruction conditions, the minimum detectable diameter of a simulated spherical calcium granule with a clinically relevant CaHA density was 0.76 mm. The minimum detectable volume was 2.4 times smaller on images reconstructed at a slice thickness of 0.625 mm compared to 2.5 mm. The detectability index d' increased by a factor of 1.7 when images were reconstructed with 0.625 mm slices compared to 2.5 mm slices. d' did not change when images were reconstructed with the high-resolution BONE filter compared to the less sharp STANDARD resolution filter on the GE Revolution CT.

CONCLUSIONS:

We have quantified detectability versus size of small calcium granules at the resolution limit of a widely available clinical CT scanner. Detectability increased significantly with reduced slice thickness and did not change with a sharper reconstruction kernel. The simulation can be used to calculate the trade-off between dose and CAC detectability.
Palabras clave

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Tipo de estudio: Guideline / Prognostic_studies / Screening_studies Idioma: En Revista: Med Phys Año: 2023 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Tipo de estudio: Guideline / Prognostic_studies / Screening_studies Idioma: En Revista: Med Phys Año: 2023 Tipo del documento: Article País de afiliación: Estados Unidos