Early time-related course of image findings in postmortem MRI: Typical findings and observer agreement in a porcine model

Haemodynamics Imaging of Swine Segmental Kidney Artery Using Duplex Doppler Technique

Introduction

The aim of the study was to assess the usefulness of duplex Doppler to objectify swine renal arterial flow in physiological conditions. The pig kidney was selected for its morphological similarities to the human and for the results therefore offering data to wider research.

Material and Methods

Six White Large x Landrace sows, of 48.5-53 kg b.w. were used. Vascular flow parameters were acquired with a convex probe USG device with a duplex Doppler function using pulsed waves (frequency range of 5-7.5 MHz). Segmental kidney arterial flow was measured.

Results

The RI values were within the 0.57 (min) to 0.6 (max) range, x _RI was 0.58 (±0.014), and the SD²value was 0.0002. The PI index values ranged from 1.21 (min) to 1.3 (max), and x _PI was 1.24 (±0.035). The value of SD²was 0.00123. In the S/D index, the results fell between 2.2 (min) and 2.49 (max), with x _S/D of 2.29 (±0.117). The value of variance SD²was 0.0139. A double analysis of correlation between indices showed this to be almost certain and highly positive as confirmed by high correlation coefficients: r _{RI & PI} 0.857, rho _{RI & PI} 0.739, r _{RI & S/D} 0.930, rho _{RI & S/D} 0.941, r _{PI & S/D} 0.913, and rho _{PI & S/D} 0.754. The segmental kidney arterial flow spectrum evinced falls in PSV and PSV/LDV ratio, also noticed in the filling of the spectral window, comparing the renal to an interlobar artery.

Conclusion

Swine were selected because of renal anatomical and haemodynamic similarity to humans. The most relevant values and indices approximated those in humans. The study anaesthetic protocol had a minor influence on the average RI, PI, and S/D indices.

Early postmortem interval estimation based on Cdc25b mRNA in rat cardiac tissue

PURPOSE

The postmortem interval (PMI) is the amount of time that has elapsed since the time of death. Over the years, many approaches have been developed to assess PMI, but their time frame of applicability has been only days to weeks. Our present pilot study aimed to find the sensitive mRNA marker if the degradation of mRNA could be used to estimate the early postmortem interval (up to 24 h).

METHODS

In our study, we use the microarray to screen 217 mRNAs markers of rat cardiac tissue. Then, real-time fluorescent quantitative PCR (qPCR) was used to validate of the candidate markers at 7 time points within 24 h and at temperatures of 25 °C and 35 °C. Another 27 rats were then used to verify the model.

RESULTS

Among all of the candidate markers, △Cq (cell division cycle 25 homolog B(Cdc25b)) had the best correlation coefficient with early postmortem interval and was used to build a new model using the R software. The results of verification testing demonstrated that the error rate was less than 15%, demonstrating the high predictive power of our mathematical model.

CONCLUSION

In this study, Cdc25b was found to be the sensitive marker to estimate early postmortem interval, and Rpl27 was found to be suitable for use as the endogenous control. Our work provided new leads for molecular approaches to early postmortem interval estimation using the significant mRNA markers established here.