Polar map analysis of small animal PET cardiac images

Objectives PET is commonly used to quantify myocardial substrate utilization and perfusion in humans and recently in small animals. In small animals, myocardial data is often quantified on a region of interest ignoring standardized segmentation of the heart. In this work, we developed an integrated software framework to perform small animal PET image analysis on 16 segmented regions following the American Heart Association’s (AHA) Standardized Myocardial Segmentation and Nomenclature for Tomographic Imaging of the Heart.

Methods In order to perform the analysis on a common template, a reorientation step is performed to make the X, Y and Z direction of the image data aligned with long and short axes of the heart. Subsequently, the heart is partitioned into basal, mid, and apical sections, and each section is further segmented in accordance with the AHA’s myocardial segmentation and nomenclature. Input function can be either loaded into the program, or obtained via methods such as factor analysis. Within the software framework, graphical analysis (Patlak, Logan), full compartmental kinetic modeling, as well as perfusion analysis can be applied on a regional basis with the result illustrated in a polar map overlaid with the LV segmentation nomenclature.

Results The framework was evaluated using a mouse FDG PET dataset to demonstrate its capability. The mouse FDG PET dataset was analyzed with the input function obtained using a factor analysis approach. Then Patlak analysis was performed on a regional basis and visualized using polar map.

Conclusions An integrated software framework for quantitative analysis of small animal myocardial PET data was developed in accordance with the AHA’s segmentation.