Use of azimuthal-invariant Mueller-matrix images of linear dichroism of histological sections of brain substance for diagnosis of hemorrhage genesis

Use of azimuthal-invariant Mueller-matrix images of linear dichroism of histological sections of brain substance for diagnosis of hemorrhage genesis Garazdiuk M.S., Dubolazov O.V., Malanchuk S.M. Bukovinian State Medical University, Chernivtsi, Ukraine Institute of Physical, Technical and Computer Sciences of Chernivtsi National University named after Yu. Fedkovych, Chernivtsi, Ukraine Municipal Non-Commercial Enterprise "City Children's Polyclinic" Chernivtsi City Council, Chernivtsi, Ukraine


Introduction
Traumatic brain injury is one of the most common types of mechanical damage to the human body [7,8,9,10,12,24]. Quite often, in forensic practice there are cases when the body was found at home under unexplained circumstances and later during the autopsy hemorrhage into the substance of the human brain (HBS) was detected. In this case forensic authorities raise questions about the genesis of hemorrhage: traumatic or non-traumatic. There are studies in which it is noted that traumatic brain injury (TBI) and strokes can coexist or occur one on background of another one, which further complicates the situation [22]. Therefore, differential diagnosis of the cause of death (CD) from ischemic cerebral infarction (ICI), hemorrhages of traumatic (HTG) and non-traumatic (HNG) genesis excluded the violent nature of death [10,12,23]. It should also be noted that the incidence of hemorrhage in the brain necessitates the study of structural alterations of HBS and the determination of reliable criteria for hemorrhage differentiation.
Typically, physicians in routine practice for differential diagnosis within the group of acute cerebrovascular disorders use computed tomography (CT) and general clinical data, but there is very little data on the differentiation of strokes of ischemic and hemorrhagic genesis and hemorrhage in HBS of traumatic origin [10,12,24]. A team of scientists led by Panzer S noted the feasibility of performing pre-mortem CT to compare it with CT immediately after injury of HBS, as well as the subsequent comparison of all CT images with autopsy results [10]. Comparison between primary CT and recent CT scans revealed marked changes in the presence and severity of signs of HBS injury, especially in patients with severe TBI. They also noted that the comparison of autopsy and CT data revealed a high level of diagnostic specificity (>80%) in the studied cases.
Recently in forensic practice optical methods of biological tissue research using lasers have positively proved themselves, which by studying the phenomena of light scattering make it possible to obtain reliable objective data of the dynamics of pre-and post-mortem changes of the studied tissues of the human body and to diagnose with greater accuracy prescription of pathological process in biological tissues and liquids [1,2,3,4,5,11,13,14,15,16,17,18,19,20,21].
The aim of our work: was to develop forensic criteria for hemorrhage differentiation of traumatic and non-traumatic genesis and ICI by azimuthal-invariant Mueller-matrix images of linear dichroism of histological sections of HBS.
For the study, the preparations were previously subjected to rapid freezing, then histologic sections were made. Subsequently, the samples were sent to the laboratory of the Yuriy Fedkovych Institute of Physical, Technical and Computer Sciences, where they were investigated using the azimuthal-invariant Muller-matrix mapping method, the way of application of the method is described in sources [5,13,15].
Measuring the coordinate allocation meanings of parameters of polarization in the points of microscopic images was carried out at the location of the standard stokes-polarimeter [3].
Experimental measurements of Stokes-parametric images of biological layers were carried out according to the method presented in these publications [3,5,15].
The values of operational characteristics that characterize the strength of the method of azimuthalinvariant Mueller-matrix polarimetry of the distributions of the linear dichroism of a set of brain tissue samples for objective statistical differentiation of causes of death are presented in table 2.
An increase in the value of sensitivity, specificity and balanced accuracy by 14-19% compared with the data of the Muller-matrix polarimetry of distributions of the Mullermatrix invariant of linear birefringence of samples of HBS [14,16].
For a set of central statistical moments of the 1st, 3rd and 4th orders, which characterize the distributions of circular dichroism, the method of Mueller matrix microscopy in the differentiation of samples of control and experimental groups reaches a satisfactory level 78-84%.
Between control group 1 (ischemic heart disease) and all experimental groups 1-3 the azimuthal-invariant Mullermatrix mapping of the polarization manifestations of LB of fibrillary nerve tissue networks of the dead demonstrates a good level of differentiation, which is 79-83%.
Diagnostic efficiency of the Mueller-matrix mapping method of polarization manifestations of LD for intergroup differentiation of samples of deaths from HTG (group 2) and ICI (group 3) reaches a satisfactory level and is 76-83%. A similar (satisfactory 75-82%) level of differentiation is achieved for samples of histological sections of deaths from HNG (group 4) and HTG (group 2).
As for differentiation between ICI (group 3) and HNG (group 4) thise method is ineffective, as the level of differentiation is from 60 to 70%.  Table 2. Specificity, sensitivity, accuracy of the method of statistical analysis of MMI of LB maps of histological sections of the brain.

Discussion
Methods of polarization tomography, based on the results of numerical display of instrumental measurement of parameters, are one of the most objective and accurate for recording changes that occurred in a biological object under the influence of environmental factors and changes in biological tissues (BT) during the pathological process. They also have the main requirement for the introduction of modern research methods in the practice of any expert field -the ability not to change the properties and condition of the object under study in its evaluation [3,19,20,21].
The method of polarization laser microscopy allows to obtain important information about the morphological structure and properties of human BT. From the optical point of view on BT they consist of 2 phases: amorphous and optically anisotropic (crystalline) [3]. Crystal structures include coaxial fibrils, which form collagen, elastin, myosin organic fibers, surrounded by fluids and media of the human body. An important feature of these fibrillar proteins is their clear order. It should be noted that polarization microscopy carries information about the degree of ordering and crystallization of the structure of BT [3].

Conclusions
1. The magnitudes of operational characteristics that characterize the power of the method of azimuthal-invariant Mueller-matrix images of linear dichroism of histological sections of human brain substance demonstrate the possibility of objective statistically significant differences by this method.
2. The effectiveness of intergroup differentiation of samples of deaths from traumatic hemorrhage and ischemic cerebral infarction reaches a satisfactory level and is 76-83%.
3. Efficiency between group differentiation of samples of deaths from nontraumatic and traumatic hemorrhages reaches a satisfactory level and is 75-82%. 4. As for differentiation between ischemic cerebral infarction and nontraumatic hemorrhages thise method is ineffective.