A template‐based approach to semi‐quantitative SPECT myocardial perfusion imaging: Independent of normal databases

Abstract

The authors introduced a method for semi-quantitative SPECT MPI, which offers a patient-specific approach to define the perfusion defect regions within the heart, as opposed to the patient-averaged NPD methodology.

Toward a practical template-based approach to semiquantitative SPECT myocardial perfusion imaging

“…Template: Heart þ background. Although the analysis using the heart only template described above exhibited satisfactory results in our previous study, 19 in the present study, we introduce a more comprehensive template where we extract information from both the SPECT image and the attenuation map (obtained via CT or a transmission scan) to include an estimate of background activity in our template.…”

“…We tested T-QPS in simulation, physical phantom and patient studies, and found that the estimated perfusion defect extent was within 5% of truth for each study. 19 Despite the encouraging results obtained in the aforementioned study, computation times for the T-QPS technique were extensive, ultimately rendering it unsuitable for use in the clinical environment. In addition, our previous study was performed using a simple template where only the heart was considered, excluding the influence of extracardiac uptake.…”

“…18 Recently, we introduced a template-based quantitative perfusion SPECT (T-QPS) method, which enables a semiquantitative assessment of abnormal perfusion in SPECT MPI, without the use of normal patient databases. 19 In brief, this technique uses the reconstructed SPECT image to create a 3D digital template of the patient's heart as if it were healthy. As opposed to other template-based methods which rely on high resolution anatomical images of the object of interest to create templates, 20,21 T-QPS generates template from the SPECT image itself.…”

Do template-based partial volume effect corrections inherently presume homogeneous uptakes?

“…As it can be seen from Fig.5, the template-based PVEC with uniformly filled template accurately restores not only total activity but its voxelized distribution for such shape of ROI. As another appealing clinical application of template based PVEC, the SPECT cardiac perfusion imaging should be mentioned [13,16]. As myocardium has relatively small thickness, the visibility of perfusion defect is largely affected by the spill-out of activity to surrounding tissues.…”

“…In such situation, tumour can be segmented and the region of interest (ROI) corresponding to the tumour extracted from the scanned object (human body). One of the promising options to correct the activity in ROI for PYE is to apply a template-based strategy [4][5][6][7][8][9][10][11][12][13][14][15][16]. This includes the generation of a digital prototype (template) of the object by "filling" the areas inside and outside the ROI with some activity.…”