We developed a prototype CdTe SPECT system with 4-pixel matched collimator for brain study. This system provides high-energy-resolution (6.6%), high-sensitivity (220 cps/MBq/head), and high-spatial-resolution images. The aim of this study was to evaluate dual-isotope study of CBF and central benzodiazepine receptor (BZR) images using 99mTc-ECD and 123I-IMZ with the new SPECT system in patients with epilepsy comparing with single-isotope study using the conventional scintillation gamma camera.
This study included 13 patients with partial epilepsy. The BZR images were acquired at 3 hours after 123I-IMZ injection for 20 minutes. The images of IMZ were acquired with a conventional 3-head scintillation gamma camera. After BZR image acquisition with the conventional camera, 99mTc-ECD was injected, and CBF and BZR images were acquired simultaneously 5 minutes after ECD injection with the new SPECT system. The CBF images were also acquired with the conventional camera on separate days. The findings were visually analyzed, and 3D-SSP maximum Z scores of lesions were compared between the 2 studies.
There were 47 abnormal lesions on BZR images and 60 abnormal lesions on CBF images in the single-isotope study with the conventional camera. Dual-isotope study with the new system showed concordant abnormal findings of 46 of 47 lesions on BZR and 54 of 60 lesions on CBF images with the single-isotope study with the conventional camera. There was high agreement between the 2 studies in both BZR and CBF findings (Cohen κ values = 0.96 for BZR and 0.78 for CBF). In semiquantitative analysis, maximum Z scores of dual-isotope study with the new system strongly correlated with those of single-isotope study with the conventional camera (BZR: r = 0.82, P < 0.05, CBF: r = 0.87, P < 0.05).
Our new SPECT system permits dual-isotope study for pixel-by-pixel analysis of CBF and BZR information with the same pathophysiological condition in patients with epilepsy.
From the *Department of Nuclear Medicine, School of Medicine, Hokkaido University, Sapporo, Hokkaido; †Hitachi Ltd Central Research Laboratory, Hitachi, Ibaraki; and Departments of ‡Psychiatry, and §Radiology, and ∥Faculty of Health Science, School of Medicine, and ¶Office of Health and Safety, Hokkaido University, Sapporo, Hokkaido, Japan.
Received for publication February 2, 2017; revision accepted May 6, 2017.
This study was approved by the Ethics Committees of both Hokkaido University Graduate School of Medicine and Hitachi Ltd. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
Authors’ Contributions: Study conception and design: T.S. and N.T. Acquisition of data: K.S., T.K., T.S., T.T., and K.H. Analysis and interpretation of data: T.S. and C.K. Drafting of manuscript: T.S. Critical revision: T.S. Developing and maintenance of a new SPECT system: A.S., W.T., and K.K.
This work was supported by the Creation of Innovation Centers for Advanced Interdisciplinary Research Areas Program, Ministry of Education, Culture, Sports, Science and Technology, Japan.
Conflicts of interest and sources of funding: N.T. has received grants from Hitachi Ltd. He was not involved in analysis of results. A.S., W.T., and K.K. were employees of Hitachi Ltd. They were not involved in both making protocol and analysis of results. They were associated with only developing and maintenance of a new SPECT system. None declared to other authors.
Correspondence to: Tohru Shiga, MD, PhD, Department of Nuclear Medicine, Graduate School of Medicine, Hokkaido University, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan. E-mail: email@example.com.