Title:Multifractal Analysis of Muscular Tissue Cryofixed in a Cryostat Chamber
Volume: 10
Issue: 4
Author(s): Giorgio Bianciardi, Francesca Pontenani and Sergio Tripodi
Affiliation:
Keywords:
Biological damage, cryofixation, cryostat, freezing tissue, intraoperative consultation, multifractal analysis.
Abstract: Cryofixation of tissues in a cryostat chamber is a routine technique to investigate rapidly
about the presence of tumours during a surgical procedure in patients (intraoperative consultation).
The tissue is placed without cryoprotectant in contact with a cooled metal block inside the cryostat
used for cutting and preparing the specimen, without or with a heavy weight. Until now, quantitative
studies of the damages produced by freezing in intraoperative consultation are lacking. To obtain
quantitative indexes we have performed fractal analysis (local fractal dimension, D0 and entropy, D1)
of the cryofixed muscular tissues in comparison to formalin-fixed samples. Seventy-two microscopic
fields or 700 muscle fibres were automatically examined. After freezing at t = 20 °C using an heavy weight, large voids
inside the cells (ice-tissue interfaces) were present, while without the use of the weight the fibres collapse (shrinkage).
Fractal analysis revealed the presence of a multifractal structure. In the formalin-fixed samples, at large scale the muscle
tissue D0 and D1 reached the values of the Diffusion-Limited Aggregation process. At large scale, after cryofixation using
the weight, D0 and D1 statistical increased (p<0.01; p<0.01), respect to the formalin-fixed samples, while, without the
weight, the values were close to the ones of formalin-fixed samples. At low scale, without the weight, D0 and
D1decreased statistically (p<0.01) compared to the formalin-fixed samples, while, with the weight, the values were close
to the ones of formalin-fixed samples. Large and low scales accurately quantified the amount of ice-tissue interfaces and
cell shrinkage, respectively.