I-123 iomazenil single photon emission computed tomography for detecting loss of neuronal integrity in patients with traumatic brain injury.
BACKGROUND
Traumatic brain injury (TBI) causes brain dysfunction in many patients. Using C-11 flumazenil (FMZ) positron emission tomography (PET), we have detected and reported the loss of neuronal integrity, leading to brain dysfunction in TBI patients. Similarly to FMZ PET, I-123 iomazenil (IMZ) single photon emission computed tomography (SPECT) is widely used to determine the distribution of the benzodiazepine receptor (BZR) in the brain cortex. The purpose of this study is to examine whether IMZ SPECT is as useful as FMZ PET for evaluating the loss of neuronal integrity in TBI patients. The subjects of this study were seven patients who suffered from neurobehavioral disability. They underwent IMZ SPECT and FMZ PET. Nondisplaceable binding potential (BPND) was calculated from FMZ PET images. The uptake of IMZ was evaluated on the basis of lesion-to-pons ratio (LPR). The locations of low uptake levels were visually evaluated both in IMZ SPECT and FMZ PET images. We compared FMZ BPNDand (LPR-1) of IMZ SPECT.


RESULTS
In the visual assessment, FMZ BPNDdecreased in 11 regions. In IMZ SPECT, low uptake levels were observed in eight of the 11 regions. The rate of concordance between FMZ PET and IMZ SPECT was 72.7%. The mean values IMZ (LPR-1) (1.95 ± 1.01) was significantly lower than that of FMZ BPND(2.95 ± 0.80 mL/mL). There was good correlation between FMZ BPNDand IMZ (LPR-1) (r = 0.80).


CONCLUSIONS
IMZ SPECT findings were almost the same as FMZ PET findings in TBI patients. The results indicated that IMZ SPECT is useful for evaluating the loss of neuronal integrity. Because IMZ SPECT can be performed in various facilities, IMZ SPECT may become widely adopted for evaluating the loss of neuronal integrity.
Department of Rehabilitation Medicine, Hokkaido University Hospital, Sapporo, 060-8638, Japan.
Kagari
K
Abiko
Department of Rehabilitation Medicine, Hokkaido University Hospital, Sapporo, 060-8638, Japan.
Katsunori
K
Ikoma
Department of Nuclear Medicine, Hokkaido University School of Medicine, North 15th, West 7th, Kitaku, Sapporo, 060-8638, Japan. tshiga@med.hokudai.ac.jp.
Tohru
http://orcid.org/0000-0002-3238-3507
T
Shiga
Department of Nuclear Medicine, Hokkaido University School of Medicine, North 15th, West 7th, Kitaku, Sapporo, 060-8638, Japan.
Chietsugu
C
Katoh
Department of Nuclear Medicine, Hokkaido University School of Medicine, North 15th, West 7th, Kitaku, Sapporo, 060-8638, Japan.
Kenji
K
Hirata
Department of Tracer Kinetics, Hokkaido University, Sapporo, 060-8638, Japan.
Yuji
Y
Kuge
Department of Nuclear Medicine, Hokkaido University School of Medicine, North 15th, West 7th, Kitaku, Sapporo, 060-8638, Japan.
Kentaro
K
Kobayashi
Department of Nuclear Medicine, Hokkaido University School of Medicine, North 15th, West 7th, Kitaku, Sapporo, 060-8638, Japan.
Nagara
N
Tamaki