Evaluation of image reconstruction methods for 123 I-MIBG-SPECT: a rank-order study

Abstract

Background

There is an opportunity to improve the image quality and lesion detectability in single photon emission computed tomography (SPECT) by choosing an appropriate reconstruction method and optimal parameters for the reconstruction.

Purpose

To optimize the use of the Flash 3D reconstruction algorithm in terms of equivalent iteration (EI) number (number of subsets times the number of iterations) and to compare with two recently developed reconstruction algorithms ReSPECT and orthogonal polynomial expansion on disc (OPED) for application on ¹²³I-metaiodobenzylguanidine (MIBG)-SPECT.

Material and Methods

Eleven adult patients underwent SPECT 4 h and 14 patients 24 h after injection of approximately 200 MBq ¹²³I-MIBG using a Siemens Symbia T6 SPECT/CT. Images were reconstructed from raw data using the Flash 3D algorithm at eight different EI numbers. The images were ranked by three experienced nuclear medicine physicians according to their overall impression of the image quality. The obtained optimal images were then compared in one further visual comparison with images reconstructed using the ReSPECT and OPED algorithms.

Results

The optimal EI number for Flash 3D was determined to be 32 for acquisition 4 h and 24 h after injection. The average rank order (best first) for the different reconstructions for acquisition after 4 h was: Flash 3D₃₂ > ReSPECT > Flash 3D₆₄ > OPED, and after 24 h: Flash 3D₁₆ > ReSPECT > Flash 3D₃₂ > OPED. A fair level of inter-observer agreement concerning optimal EI number and reconstruction algorithm was obtained, which may be explained by the different individual preferences of what is appropriate image quality.

Conclusion

Using Siemens Symbia T6 SPECT/CT and specified acquisition parameters, Flash 3D₃₂ (4 h) and Flash 3D₁₆ (24 h), followed by ReSPECT, were assessed to be the preferable reconstruction algorithms in visual assessment of ¹²³I-MIBG images.