Effects of isoflurane anaesthesia depth and duration on renal function measured with [99mTc]Tc-mercaptoacetyltriglycine SPECT in mice

Fabian Schmitz-Peiffer; Mathias Lukas; Ajay-Mohan Mohan; Jakob Albrecht; Jörg R Aschenbach; Winfried Brenner; Nicola Beindorff

doi:10.1186/s13550-023-01065-3

Effects of isoflurane anaesthesia depth and duration on renal function measured with [^99mTc]Tc-mercaptoacetyltriglycine SPECT in mice

EJNMMI Res. 2024 Jan 5;14(1):4. doi: 10.1186/s13550-023-01065-3.

Authors

Fabian Schmitz-Peiffer^{1

2}, Mathias Lukas¹, Ajay-Mohan Mohan^{1

2}, Jakob Albrecht^{1

3}, Jörg R Aschenbach⁴, Winfried Brenner^{1

2}, Nicola Beindorff⁵

Affiliations

¹ Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.
² Berlin Experimental Radionuclide Imaging Center (BERIC), Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
³ Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
⁴ Institute of Veterinary Physiology, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
⁵ Berlin Experimental Radionuclide Imaging Center (BERIC), Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany. nicola.beindorff@charite.de.

Abstract

Background: The influence of anaesthetic depth and the potential influence of different anaesthetic beds and thus different handling procedures were investigated in 86 severe combined immunodeficient (SCID) mice using semi-stationary dynamic single photon emission computed tomography (SPECT) for kidney scintigraphy. Therefore, isoflurane concentrations were adjusted using respiratory rate for low (80-90 breath/min) and deep anaesthesia (40-45 breath/min). At low anaesthesia, we additionally tested the influence of single bed versus 3-mouse bed hotel; the hotel mice were anaesthetized consecutively at ~ 30, 20, and 10 min before tracer injections for positions 1, 2, and 3, respectively. Intravenous [^99mTc]Tc-MAG3 injection of ~ 28 MBq was performed after SPECT start. Time-activity curves were used to calculate time-to-peak (Tmax), T50 (50% clearance) and T25 (75% clearance).

Results: Low and deep anaesthesia corresponded to median isoflurane concentrations of 1.3% and 1.5%, respectively, with no significant differences in heart rate (p = 0.74). Low anaesthesia resulted in shorter aortic blood clearance half-life (p = 0.091) and increased relative renal tracer influx rate (p = 0.018). A tendency toward earlier Tmax occurred under low anaesthesia (p = 0.063) with no differences in T50 (p = 0.40) and T25 (p = 0.24). Variance increased with deep anaesthesia. Compared to single mouse scans, hotel mice in position 1 showed a delayed Tmax, T50, and T25 (p < 0.05 each). Furthermore, hotel mice in position 1 showed delayed Tmax versus position 3, and delayed T50 and T25 versus position 2 and 3 (p < 0.05 each). No difference occurred between single bed and positions 2 (p = 1.0) and 3 (p = 1.0).

Conclusions: Deep anaesthesia and prolonged low anaesthesia should be avoided during renal scintigraphy because they result in prolonged blood clearance half-life, delayed renal influx and/or later Tmax. Vice versa, low anaesthesia with high respiratory rates of 80-90 rpm and short duration (≤ 20 min) should be preferred to obtain representative data with low variance.

Keywords: Hotel; Isoflurane concentration; Respiratory rate; Single mouse bed; [99mTc]Tc-MAG3.