Diffusion tensor imaging of formalin fixed infarcted porcine hearts

Value of Formalin Fixation for the Prolonged Preservation of Rodent Myocardial Microanatomical Organization: Evidence by MR Diffusion Tensor Imaging

“…(2013) showed similar HA transmural variation in a Wistar rat heart imaged 2‐hr post‐fixation. Other DTI studies with fixation periods shorter than 2 weeks (Mazumder et al, ; Watson and Hsu, ) have used different species and imaging protocols making comparisons difficult.…”

“…(iii) The results question the use of DTI in microstructural studies of cardiac samples exposed to formalin for a prolonged period that exceeds 6 weeks prior to imaging. In fact, there are numerous ex vivo cardiac DTI studies, where the specimens remained in formalin for a prolonged period (for example, over a month in (Jiang et al, ; Abdullah et al, ), 6 months in (Mazumder et al, ), over a year in (Eggen et al, ), to name a few) prior to imaging. According to the findings of this article, caution should be exercised in adopting the results from such studies.…”

“…Indeed, a few studies attempted to address the question whether one can extrapolate cardiac DTI results from fixed to freshly excised tissue, but the results were conflicting. That is to say, on the one hand, Mazumder et al () demonstrated that formalin fixation resulted in the cardiomyocyte diffusion pattern becoming more isotropic, while, on the other hand, Gilbert et al () found no changes in cardiac microstructure following the formalin fixation process. In spite of the cardiac DTI parameter comparison between the ex vivo and in vivo settings being beyond the scope of this article, the results obtained in this study (from the samples that remained in formalin for a shorter time period) appear to resonate with in vivo cardiac DTI results (Chen et al, ) acquired from the same animal.…”

“…The bases for this assumption were: (i) Histology‐based experimental observations (Fox et al, ) that the tissue reaches an equilibrium state after the initial crosslinking actions, and (ii) former findings from some individual non‐cardiac longitudinal studies (Kim et al, ; Dyrby et al, ) demonstrating stability of DTI parameters over a prolonged (namely, several weeks for cervical spinal cord and 3 years for brain) period of tissue exposure to formalin. A recent cardiac DTI study (Watson and Hsu, ) that aimed at evaluating the effects of fixation duration on DTI parameters showed that, after some initial changes (that took place the first 48 hr following the tissue immersion in the formaldehyde‐based solution), the DTI parameters remained stable for up to 7 days; however, it happens frequently (Jiang et al, ; Eggen et al, ; Mazumder et al, ; Abdullah et al, ) that the cardiac tissue is exposed to formalin for a much more prolonged period prior to imaging.…”