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January 26, 2011European Journal of Nuclear Medicine and Molecular Imaging169 citationsOpen Access

Automatic generation of absolute myocardial blood flow images using 15OH2O and a clinical PET/CT scanner

HHHendrik J. HarmsPKPaul KnaapenSHStefan de Haan

Key Result

Automatic generation of parametric myocardial blood flow images using a basis function method and cluster analysis showed high agreement with manually derived nonlinear least-squares regression (ICC 0.984).

Study Design

Type

Observational (n=19)

Multicenter

No

Structured PICO

Does automatic generation of parametric MBF images using cluster analysis and BFM agree with manually derived MBF using NLR in patients undergoing [15O]H2O PET/CT?

P
Population
19 consecutive patients (9 men, mean age 65; 10 women, mean age 60) referred for CT angiography and MBF measurements, with no documented history of CAD, no signs of previous MI, and normal LV function.
I
Intervention
Automatic generation of parametric myocardial blood flow (MBF) images using a basis function method (BFM) of the single-tissue model with RV spillover correction, evaluating four segmentation algorithms (cluster analysis, FADS, factor analysis, k-means++).
C
Comparator
MBF obtained using nonlinear least-squares regression (NLR) of VOI data and manually defined input functions.
O
Outcome
Agreement (intraclass correlation coefficient) between average segmental MBF derived from parametric images and MBF obtained using NLR, and agreement between automatic segmentation algorithms and manually obtained input functions.surrogate

Parametric MBF images of diagnostic quality can be generated automatically using cluster analysis and a basis function method with RV spillover correction, showing high agreement with manual methods.

Main Result

Effect estimate: ICC 0.984

Limitations

  • Data were cropped around the heart using fixed parameters to prevent memory issues, which may affect the optimal number of clusters.
  • Segmentation algorithms included larger volumes than manually obtained TACs, introducing dispersion and partial volume effects that resulted in higher apparent MBF.
  • Cluster analysis occasionally (<5%) failed to separate aorta from myocardium.
  • K-means++ persistently included myocardial voxels in the arterial factor for stress scans.
  • FADS and factor analysis were unable to segment the RV correctly.

Abstract

PURPOSE: Parametric imaging of absolute myocardial blood flow (MBF) using (15)OH(2)O enables determination of MBF with high spatial resolution. The aim of this study was to develop a method for generating reproducible, high-quality and quantitative parametric MBF images with minimal user intervention. METHODS: Nineteen patients referred for evaluation of MBF underwent rest and adenosine stress (15)OH(2)O positron emission tomography (PET) scans. Ascending aorta and right ventricular (RV) cavity volumes of interest (VOIs) were used as input functions. Implementation of a basis function method (BFM) of the single-tissue model with an additional correction for RV spillover was used to generate parametric images. The average segmental MBF derived from parametric images was compared with MBF obtained using nonlinear least-squares regression (NLR) of VOI data. Four segmentation algorithms were evaluated for automatic extraction of input functions. Segmental MBF obtained using these input functions was compared with MBF obtained using manually defined input functions. RESULTS: The average parametric MBF showed a high agreement with NLR-derived MBF intraclass correlation coefficient (ICC) = 0.984. For each segmentation algorithm there was at least one implementation that yielded high agreement (ICC > 0.9) with manually obtained input functions, although MBF calculated using each algorithm was at least 10% higher. Cluster analysis with six clusters yielded the highest agreement (ICC = 0.977), together with good segmentation reproducibility (coefficient of variation of MBF <5%). CONCLUSION: Parametric MBF images of diagnostic quality can be generated automatically using cluster analysis and a implementation of a BFM of the single-tissue model with additional RV spillover correction.

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Cite This Study

Harms et al. (2011) conducted an observational in Evaluation for coronary artery disease (n=19). Automatic parametric imaging using basis function method and cluster analysis vs. Nonlinear least-squares regression with manually defined input functions was evaluated on Agreement between average parametric MBF and NLR-derived MBF (ICC 0.984). Automatic generation of parametric myocardial blood flow images using a basis function method and cluster analysis showed high agreement with manually derived nonlinear least-squares regression (ICC 0.984).

synapsesocial.com/papers/6a15b025b03a896dfa823a4fhttps://doi.org/10.1007/s00259-011-1730-3
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