Retention of Tc-99m ECD in delayed SPECT of the brain

Flores, Leo G.; Jinnouchi, Seishi; Nagamachi, Shigeki; Ohnishi, Takashi; Futami, Shigemi; Nakahara, Hiroyuki; Shimoshinbara, Shigeru; Ushinbana, Kenji; Tamura, Shozo

doi:10.1007/bf03165420

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…There is one in vitro study supporting the hypothesis that esterase activity is the major determinant of the overall retention of ECD (Jacquier-Sarlin, Polla, & Slosman, 1996). Evidence about regional variation for clearance of [ 99m Tc]Tc-ECD in normal brain are controversial (Flores et al, 1999;Ichise et al, 1997;Leveille et al, 1989). In a study of epilepsy, [ 99m Tc]Tc-ECD washout rate was reported to be slightly lower but statistically signi cant in the hyperperfused areas than in other brain areas.…”

Section: Introductionmentioning

confidence: 99%

A Novel method of seizure onset zone localization by serial Tc-99 m ECD brain perfusion SPECT clearance patterns

Sukprakun

Limotai

Khamwan

et al. 2022

Brain Imaging and Behavior

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In this prospective study, we postulate that there is a difference between clearance of [99mTc]Tc-ethyl cysteinate dimer (ECD) in the seizure onset zone (SOZ) and other brain areas and thus SOZ localization by clearance patterns might become a potential novel method for SOZ localization in epilepsy. The parametric images of brain ECD clearance were generated by linear regression model analysis from serial brain SPECT scans from 30 minutes to 240 minutes after ECD injection (7-times point) in 7 patients with drug-resistant epilepsy and 3 normal volunteers. Clearance patterns of the SOZ con rmed by good surgical outcome or consensus with other investigations were analyzed quantitatively and semi-quantitatively by visual grading (slower or faster washout than contralateral brain regions). The average [ 99m Tc]Tc-ECD clearance rates of SOZs were + 1.08 % ± 2.57 %/hr (wash in), -7.02 % ± 2.56 %/hr (washout), and − 5.37% ± 1.71 %/hr (washout) in ictal, aura and interictal states, respectively. Paired t-tests between the SOZ and contralateral regions showed statistically signi cant difference (p = 0.039 in interictal state). Clearance patterns that can de ne the SOZs were 1) wash in and slow washout on ictal slope, 2) fast washout on aura slope and interictal slope with 100% (6/6), 100% (2/2) and 75% (6/8) localization using ictal, aura, and interictal slope maps, respectively. Our study provided the evidence that clearance pattern methods are potential additive diagnostic tools for SOZ localization when routine one-time point SPECT are unable to de ne the SOZ.

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Section: Introductionmentioning

confidence: 99%

A Novel method of seizure onset zone localization by serial Tc-99 m ECD brain perfusion SPECT clearance patterns

Sukprakun

Limotai

Khamwan

et al. 2022

Brain Imaging and Behavior

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“…The correction for the relative 99m Tc-ECD clearance described by Ichise et al [16] was calculated in a sample of 20 healthy volunteers with a mean age of 35±10 years, employing anatomically standardised subject data, an ROI analysis and curve fitting techniques. On the other hand, Flores et al investigated this matter in seven volunteers and seven patients, with manual redrawing of the ROIs on each image [21]. Overall, significantly lower washout values were obtained, while the relative thalamic uptake was even reported to increase with time.…”

Section: Discussionmentioning

confidence: 91%

Transfer of normal 99mTc-ECD brain SPET databases between different gamma cameras

et al. 2001

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A stereotactic, normal perfusion database is imperative for optimal clinical brain single-photon emission tomography (SPET). However, interdepartmental use of normal data necessitates accurate transferability of these data sets. The aim of this study was to investigate transfer of three normal perfusion databases obtained in the same large population of healthy volunteers who underwent sequential scanning using multihead gamma cameras with different resolution. Eighty-nine healthy adults (46 females, 43 males; aged 20-81 years) were thoroughly screened by history, biochemistry, physical and full neurological examination, neuropsychological testing and magnetic resonance imaging. After injection of 925 MBq technetium-99m labelled ethyl cysteinate dimer (ECD) under standard conditions, 101 scans were acquired from all subjects (12 repeat studies) on a triple-head Toshiba GCA-9300A (measured average FWHM 8.1 mm). Ninety-one sequential scans were performed on a dual-head Elscint Helix camera (FWHM 9.6 mm) and 22 subjects also underwent imaging on a triple-head Prism 3000 (FWHM 9.6 mm). Images were transferred to the same processing platform and reconstructed by filtered back-projection with the same Butterworth filter (order 8, cut-off 0.9 cycles/cm) and uniform Sorensen attenuation correction (mu = 0.09). After automated rigid intrasubject registration, all subjects were automatically reoriented to a stereotactic template by a nine-parameter affine transformation. The databases were analysed using 35 predefined volumes of interest (VOIs) with normalisation on total VOI counts. For comparison, the high-resolution data were smoothed with a 3D Gaussian kernel to achieve more similar spatial resolution. Hoffman phantom measurements were conducted on all cameras. Partial volume effects after smoothing varied between -6.5% and 10%, depending on VOI size. Between-camera reproducibility was 2.5% and 2.7% for the Toshiba camera versus the Helix and the Prism database, respectively. The highest reduction in between-camera variability was achieved by resolution adjustment in combination with linear washout correction and a Hoffman phantom-based correction. In conclusion, transfer of normal perfusion data between multihead gamma cameras can be accurately achieved, thereby enabling widespread interdepartmental use, which is likely to have a positive impact on the diagnostic capabilities of clinical brain perfusion SPET.

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“…Radiochemical purity (RCP) of Tc-99m-ECD is used for the quality control (QC) purpose [14–16]. Although the characteristics of Tc-99m-ECD, such as in vivo kinetics and biodistribution studies in healthy human [15, 17], pharmacological studies in primates [14, 18], uptake, clearance, and brain retention [19–22], biotransformation, metabolites, and stability [14, 21, 23], have been well-investigated, the chemical properties (such as purity and content) of ECD in ECD Kit (Vial A), that is, API in drug product, which might significantly disqualify the efficacy of Tc-99m-ECD have not been much discussed. Moreover, no analytical method for the determination of content and uniformity of ECD in ECD Kit has been published.…”

Section: Introductionmentioning

confidence: 99%

Direct Determination of ECD in ECD Kit: A Solid Sample Quantitation Method for Active Pharmaceutical Ingredient in Drug Product

Chao

Liu²,

Hsia³

et al. 2011

BioMed Research International

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Technetium-99m ethyl cysteinate dimer (Tc-99m-ECD) is an essential imaging agent used in evaluating the regional cerebral blood flow in patients with cerebrovascular diseases. Determination of active pharmaceutical ingredient, that is, L-Cysteine, N, N′-1,2-ethanediylbis-, diethyl ester, dihydrochloride (ECD) in ECD Kit is a relevant requirement for the pharmaceutical quality control in processes of mass fabrication. We here presented a direct solid sample determination method of ECD in ECD Kit without sample dissolution to avoid the rapid degradation of ECD. An elemental analyzer equipped with a nondispersive infrared detector and a calibration curve of coal standard was used for the quantitation of sulfur in ECD Kit. No significant matrix effect was found. The peak area of coal standard against the amount of sulfur was linear over the range of 0.03–0.10 mg, with a correlation coefficient (r) of 0.9993. Method validation parameters were achieved to demonstrate the potential of this method.

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Retention of Tc-99m ECD in delayed SPECT of the brain

Cited by 6 publications

References 3 publications

A Novel method of seizure onset zone localization by serial Tc-99 m ECD brain perfusion SPECT clearance patterns

A Novel method of seizure onset zone localization by serial Tc-99 m ECD brain perfusion SPECT clearance patterns

Transfer of normal 99mTc-ECD brain SPET databases between different gamma cameras

Direct Determination of ECD in ECD Kit: A Solid Sample Quantitation Method for Active Pharmaceutical Ingredient in Drug Product

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