Dissociation of 99mTc-ECD and 99mTc-HMPAO distributions in herpes simplex encephalitis.
In herpes simplex encephalitis (HSE), the authors noted an evident dissociation between the 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-d,l-hexamethyl-propylene-amine oxime (HMPAO) single photon emission computed tomographies (SPECTs). The patient was a 5-year-old boy with diffuse type of pontine glioma, which was treated with hyperfractionated radiotherapy. Two weeks after the completion of radiation therapy, a lesion suggesting that of HSE was noted in the right fronto-temporal region on magnetic resonance images. 99mTc-HMPAO SPECT showed an increased accumulation of the tracer in this lesion. On the 99mTc-ECD dynamic SPECT, an exaggerated accumulation of the tracer was noted within 80 s of administration, followed by a rapid drop in the accumulation, resulting in a low accumulation in 10 min. It was assumed that this dissociation was due to the different mechanisms to trap HMPAO and ECD in the brain tissue.
Tohyama
Y
Y
Department of Neurosurgery, Asahikawa Medical College, Hokkaido, Japan.
Sako
K
K
Daita
G
G
Yonemasu
Y
Y
Shuke
N
N
Aburano
T
T
D001921:Brain / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D002675:Child, Preschool; D016371:Cranial Irradiation; D003545:Cysteine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D018792:Encephalitis, Viral / Q000000981:diagnostic imaging*; D005910:Glioma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D006561:Herpes Simplex / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D011149:Pons / Q000000981:diagnostic imaging / Q000528:radiation effects; D017556:Technetium Compounds / Q000493:pharmacokinetics; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; D010091:Oximes; D017556:Technetium Compounds; C031752:ethyl cysteine; D019690:Technetium Tc 99m Exametazime; D003545:Cysteine