Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination

: This case report focuses on the findings in what appeared to be a planned complex pistol head shot and train suicide. The post mortem computed tomography (PMCT) scan in this instance yielded two interesting skull fragments among the many fragments of a highly fragmented body and head. These two fragments, based on initial resolution, appeared to show findings consistent with a firearm shot to the head. Upon reconstruction of higher resolution data, the necessary discrimination of non-gunshot related semi-circular fragment rims and firearm-related beveling matched the macroscopic aspect of the skull fragments. As a first lesson to be learned, a thorough examination of PMCT data in relatively high degrees of fragmentation may have to inspect all bone edges also for relatively subtle changes, possibly indicative of sharp force trauma or gunshot trauma. To that end, individual bone fragments should be placed on the scanner table carefully and with proper spacing, to expose their edges. Only this allows to capture data that avoids edge overlaps or edge collisions and that allows for optimal checking of the edges of all bone fragments for possible semicircular defects in the PMCT data. A second technical lesson to be learned is that particularly in instances of high fragmentation of at least parts of a body, resolution may have to be at least as good as maximally achievable. To that end, availability of the raw data to reconstruct images with maximal image quality rather than using a trade-off between lesser cost and lesser yield may be a key issue. A third lesson to be learned is that findings in relatively highly fragmented bodies as consequence of an apparent form of injury - fire/thermal, fall from great height, collision with a train - for other forms of trauma - sharp force trauma, firearm injury - may have to interpreted with caution, particularly with regard to what can be ruled out. Abstract This case report focuses on the ﬁndings in what appeared to be a planned complex pistol head shot and train suicide. The post mortem computed tomography (PMCT) scan in this instance yielded two interesting skull fragments among the many fragments of a highly fragmented body and head. These two fragments, based on initial resolution, appeared to show ﬁndings consistent with a ﬁrearm shot to the head. Upon reconstruction of higher resolution data, the necessary discrimination of non-gunshot related semi-circular fragment rims and ﬁrearm-related beveling matched the macroscopic aspect of the skull fragments. As a ﬁrst lesson to be learned, a thorough examination of PMCT data in relatively high degrees of fragmentation may have to inspect all bone edges also for relatively subtle changes, possibly indicative of sharp force trauma or gunshot trauma. To that end, individual bone fragments should be placed on the scanner table carefully and with proper spacing, to expose their edges. Only this allows to capture data that avoids edge overlaps or edge collisions and that allows for optimal checking of the edges of all bone fragments for possible semicircular defects in the PMCT data. A second technical lesson to be learned is that particularly in instances of high fragmentation of at least parts of a body, resolution may have to be at least as good as maximally achievable. To that end, availability of the raw data to reconstruct images with maximal image quality rather than using a trade-oﬀ between lesser cost and lesser yield may be a key issue. A third lesson to be learned is that ﬁndings in relatively highly fragmented bodies as consequence of an apparent form of injury - ﬁre/thermal, fall from great height, collision with a train - for other forms of trauma - sharp force trauma, ﬁrearm injury - may have to interpreted with caution, particularly with regard to what can be ruled out.

To that end, individual bone fragments should be placed on the scanner table carefully and with proper spacing, to expose their edges. Only this allows to capture data that avoids edge overlaps or edge collisions and that allows for optimal checking of the edges of all bone fragments for possible semicircular defects in the PMCT data. A second technical lesson to be learned is that particularly in instances of high fragmentation of at least parts of a body, resolution may have to be at least as good as maximally achievable. To that end, availability of the raw data to reconstruct images with maximal image quality rather than using a trade-off between lesser cost and lesser yield may be a key issue. A third lesson to be learned is that findings in relatively highly fragmented bodies as consequence of an grade blunt trauma skull fragmentation due to a train impact produces shape 27 1 Regarding firearm injuries to the head and PMCT, some studies issued a concise scope of the method capability [5], others explicitly mentioned several limitations of PMCT but not bone morphology [6, 7], or they did not detail specific PMCT-related limitations but added autopsy findings [8, 9, 10, 11]), while one study stated PMCT to be highly sensitive in identifying the main forensic items in gunshot victims [10].
2 From [6]: "(..) example of the limitations of the postmortem MSCT method, the most important of which are imposed by the absolute resolution of the systems (..)," 3 From [12]: "(..) Bones are well seen on CT and even if heavily burnt or even calcined, still readily recognizable." (...) "In only one case was there the suggestion of bone injury that might have been a mechanism of death other than the effects of fire, i.e. C6,7 dislocation. This finding was relayed to the pathologist prior to autopsy and lead to a detailed anatomical dissection of the deceased's neck that otherwise would not have been performed. (..) " -From [13]: "(..) the (..) authors suggested that (..) an external body description and osteological report of the remains could be conducted from 3D reconstructions (..)" -From [14]: (..) The imaging protocol needs to be tailored to the particular needs of the investigation and data handling capabilities. However, considering the hardware and software needs and the capability of all current CT scanners it should be possible to perform an optimal CT study in all instances (..) Reducing slice thickness whilst maintaining image quality (signal-to-noise ratio) requires higher x-ray exposure, increasing x-ray tube heating (tube-loading), which may be a problem for older generation CT scanners. (..) If tube-loading alerts prevent setting the required scan thickness, do not scan at lower resolution but consider: reducing individual scan lengths, increasing scan time, higher kV and lower mAs, apply auto-mA", etc. in accordance with technical experience (..) Scanning the head and cervical spine separately also allows for a smaller FoV, increasing the spatial resolution.(..) 4 From [15]: (..) "Forensic pathologists were stated to be ethically responsible to examine all human remains, regardless of size, preservation status and despite their specific challenges" (...). "Small fragments may have identifiable features, such as ridge detail, which can assist or progress positive identification" (..) Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:403 details whose forensic discrimination requires a sufficiently high resolution. The  Figure 2: Fragment 1 -On initial whole body PMCT (A), the imaging data of this bone fragment appeared to exhibit a semicircular defect (yellow dashed circle labelled x ) that initially seemed possibly consistent with the assumption of a perforating pistol shot injury with outward beveling (B, yellow dashed line, reference to fragment of image B see white dashed line in A). More refined PMCTA reconstructions from same CT raw data (C-E) correlated better with the physical bone fragment margins whereas curvature on outer (D, F) (but not inner, E and G) compact table was that of a ruptured bone suture line. Ultimately, only the photographic appearance of the bone fragment contours allow to understand how the relatively low resolution of the CT images imply what appears to be a semicircular defect. Bar 10 mm.

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No written suicide note was identified at the scene or at the victim's home.

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For further examination including identification and CT scanning, the body was 68 admitted to our institute. The scanner setup used here is a dedicated post-mortem scanner. For heightened hygiene aspects in cases of clinical radiology scanner use, appropriate containers may have to be used.
Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:407 layout of the skull fragments: an additional scan (Fig. 1 G, H; Fig 2 A   Screening of the whole body PMCT identified two skull fragments that came 99 into closer consideration for possible perforating pistol shot injuries, where we 100 clearly focused on typical rather than atypical morphology [18]. They were la-101 beled fragment 1 (Fig. 2) and 2 (Fig. 3).

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Fragment 1 (Fig. 2) measured 40 × 26 × 3, 5 mm. It contained a semi-103 circular indent on one edge that was apparent already on whole body PMCT. It 104 appeared to be an at least halfway plausible candidate for a "typical" perforating 105 Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:408 skull defect 6 , roughly consistent with a 7,65 mm caliber pistol 7 . Subsequently 106 higher resolution data analysis and macroscopic validation showed this finding to 107 be a ruptured bone suture line.

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Fragment 2 (Fig. 3)  be ruled out with certainty, no actual evidence for homicidal death was found.

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The possibility of accidental death was not pursued further in that the Swiss Pe-129 6 From [18], page 100: "When a bullet perforates bone, it bevels out the bone in the direction in which it is traveling (...). The entrance has a round to oval, sharp-edged, punched-out appearance (...). The opposite surface of the bone, i.e., the exit side, is excavated in a cone-like manner (...). This difference in appearance of entrance and exit wounds is best seen in the flat bone of skull. As the bullet enters, it creates a round to oval sharp-edged hole in the outer table of the skull, with a large, beveled-out hole on the inner table. When the bullet exits the cranial cavity, the inner table is the entrance surface and the outer table the exit surface.Chips of bone can flake off the edge of an entrance hole." 7 While the shape variation of firearm related injuries may be regarded as sufficiently wide to stay clear of overly specific expectations, fracture morphology still may allow for differentiation: take, for example, a sharply demarcated rectangular slit-like fracture in a skull e.g. measuring 1 x 45 mm. Such a lesion may be seen as "typical" for a sharp blade, but not at all as "typical" for a 7,65 mm caliber firearm ammunition. It is in that context where we approached morphology by searching "plausible candidates" or lesions "consistent with" the assumption of at least a "typical" gunshot injury to the head, in the overall context of this case.
nal Code commands that, when no evidence of third party involvement is found, 130 the district attorney releases the body without autopsy.  In one study examining fatal gunshot wounds, 5% of the cases did not contain a 154 bone lesion or an intracorporeal projectile [27].

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Absence of clearly identifiable blood aspiration to the lungs in this instance 156 does not preclude a firearm injury to the head seconds before the train caused the 157 severe head injuries [20]. Victims of planned complex suicides tend to be male 158 and of an average age over 50 years [24].    Generally, digitizing analog shapes with focus on quality may require that a 190 feature or structure be captured with at least 24 digital elements; as example, a 191 1 mm sized feature is recommended to be scanned with a resolution of at least 192 Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:4011 ∼1/24 mm, i.e., ∼615 dpi, for sufficiently high quality. Conversely, ∼15 digital 193 elements per mm (∼385 dpi) may be required for medium quality and with ∼11 194 digital elements per mm (∼277 dpi) a relatively low quality [30] may be achieved.

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In this instance, digitization of a perforating injury of an arbitrarily chosen 10 196 mm diameter may just barely conform to these requirements for high quality 197 data with a voxel size anywhere between 0,4 (high quality) to 0,9 (low quality) 198 mm. If one however does not regard the whole defect related to a gunshot skull 199 penetration as the single feature to be digitized but its firearm-typical lesion  The interpretation of fracture and fragmentation causes in cases with a high 216 degree of fragmentation will have to be worded cautiously. Leading up to that, 217 however, any practical differentiation should be attempted to the degree possible.

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There, it appears that even in instances of high degrees of bone fragmentation, 219 differentiation between hammer-stone percussion, carnivore gnawing, weathering,  Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:4012 With fragments attributable to a single case, physical assembly may be at-226 tempted in order to reconstruct a fracture pattern [42]. However, even automated 227 virtual assembly of bone fragments will also require sufficiently high resolution 228 to allow for adequate fracture edge shape encoding [43,44].  Planned complex suicide combining pistol head shot and train suicide and Virtopsy examination ·14 th Dec, 2021·20:4013 Conflicts of interest 254 The authors declare that they have no competing interests.