Feasibility in the clinical setting of perfusion brain SPECT imaging employing a brain-dedicated gamma camera and the conjugate gradients with modified matrix reconstruction method

In the present study, we compared Tc-99m HMPAO single photon emission compu ted tomography (SPECT) brain images obtained using the conventional filtere d backprojection (FBP) reconstruction method with the new reconstruction me thod of conjugate gradients with modified matrix (CGMM). The two methods we re employed to generate SPECT images of a brain perfusion study in a 41-yea r-old patient who had suffered from multiple embolisation of the right hemi sphere. Marked improvement in spatial resolution was achieved by CGMM recon struction as compared to FBP reconstruction; this considerably helped in de fining grey matter structures and low-uptake white-matter areas, both in th e normal cerebral areas and in the hemisphere that had been affected by str oke. Although the relatively long time still required by the CGMM procedure might be considered as a significant drawback to date, with the increasing diffusion of the new computer facilities the CGMM method can be proposed a s a valuable alternative to the standard FBP technique in order to better r ecognise cerebral areas with different tracer uptake.