Technetium-99m-ECD SPECT Fails to Show Focal Hyperemia of Acute Herpes Encephalitis

J Nucl Med. 1998 May;39(5):790-2.


This is a case of herpes simplex encephalitis (HSE) examined with 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-hexamethyl propyleneamine oxime (HMPAO) SPECT. Static images obtained with 99mTc-ECD showed a reduced tracer uptake of the temporal lobe but focal hyperactivity using 99mTc-HMPAO. Dynamic images indicated regional increase of cerebral blood perfusion with both tracers. Technetium-99m-ECD had rapid washout from the inflamed tissue, while 99mTc-HMPAO had avid uptake. Hypofixation of 99mTc-ECD leads to failure to detect the characteristic finding of temporal lobe hyperemia in acute HSE.

Publication types

  • Case Reports

MeSH terms

  • Acute Disease
  • Aged
  • Brain / blood supply
  • Brain / diagnostic imaging*
  • Cysteine / analogs & derivatives*
  • Encephalitis, Viral / diagnostic imaging*
  • Encephalitis, Viral / virology
  • Female
  • Herpes Simplex / diagnostic imaging*
  • Humans
  • Hyperemia / diagnostic imaging
  • Organotechnetium Compounds*
  • Radiopharmaceuticals*
  • Technetium Tc 99m Exametazime
  • Tomography, Emission-Computed, Single-Photon*


  • Organotechnetium Compounds
  • Radiopharmaceuticals
  • Technetium Tc 99m Exametazime
  • technetium Tc 99m bicisate
  • Cysteine