CT nonuniform attenuation and TEW scatter corrections in brain Tc-99m ECD SPECT

Clin Nucl Med. 2011 Aug;36(8):665-8. doi: 10.1097/RLU.0b013e318217544c.


Perfusion brain single photon emission computed tomography (SPECT) is currently used to evaluate patients with cognitive impairments. Although widely available, it has been reported to be significantly less sensitive than F-18 FDG positron emission tomography. Optimization of SPECT parameters using nonuniform attenuation correction (NUAC) and scatter correction (SC) might improve the accuracy of the method. This study assessed the effect of x-ray CT-based NUAC and triple-energy window (TEW-SC) on brain SPECT compared with Chang-uniform (UAC). A total of 31 patients with memory complaints underwent Tc-99m ECD SPECT/CT. CT-NUAC+TEW-SC and Chang-UAC were applied and compared. The images were spatially normalized to a default SPECT template supplied with Statistical Parametric Mapping software (SPM2). A paired t test image was then reconstructed. Regional cerebral blood flow measurements were apparently reduced in the frontal white-matter and in the frontotemporal cortex when CT-NUAC+TEW-SC were used. These findings need to be considered when interpreting Tc-99m ECD SPECT after applying CT-AC+TEW-SC. Further prospective studies with clinical correlations are needed.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Brain / diagnostic imaging*
  • Brain / physiopathology
  • Cysteine / analogs & derivatives*
  • Female
  • Humans
  • Male
  • Memory Disorders / diagnostic imaging
  • Memory Disorders / physiopathology
  • Middle Aged
  • Organotechnetium Compounds*
  • Retrospective Studies
  • Scattering, Radiation*
  • Tomography, Emission-Computed, Single-Photon / methods*
  • Tomography, X-Ray Computed / methods*


  • Organotechnetium Compounds
  • technetium Tc 99m bicisate
  • Cysteine