The Effect of Skin Debris on Gunshot Residue Sampling and Detection

These experiments were designed to determine whether skin debris (desquamated epithelial cells and apparent skin oils) affects gunshot residue (GSR) particle detection on the sticky tape lift samples prepared for scanning electron microscopy (SEM). A dabbing experiment showed that GSR particles accumulate not only on the adhesive surface of the sampler, but also on the epithelial cell surfaces. Samplers were loaded with target GSR followed by dabbing 30 times on the back of a hand. Backscatter electron images were taken at 20 kV and for some at 30 kV of the same areas. The samplers were then treated with a sodium/calcium hypochlorite solution (bleach) to remove skin debris and again imaged in the SEM. Comparison of these images shows more GSR particles will likely be revealed at 30 kV than 20 kV and more particles revealed by the bleach treatment in an automated SEM system.     

Visualization of Latent Blood Stains Using Visible Reflectance Hyperspectral Imaging and Chemometrics

The detection of latent traces is an important aspect of crime scene investigation. Blood stains on black backgrounds can be visualized using chemiluminescence, which is invasive and requires a darkened room, or near-infrared photography, for which investigators need to change filters manually to optimize contrast. We demonstrated the performance of visible reflectance hyperspectral imaging (400–720 nm) for this purpose. Several processing methods were evaluated: single wavelength bands, ratio images, principal component analysis (PCA), and “SIMPLe-to-use Interactive Self-modeling Mixture Analysis” (SIMPLISMA). Using these methods, we were able to enhance the contrast between blood stains and 12 different fabrics. On black cotton, blood dilutions were visible with a minimal concentration of 25% of whole blood. The hyperspectral camera system used in this study is portable and wireless, which makes it suitable for crime scene use. The described technique is noncontact and nondestructive, so all traces are preserved for further analysis.     

放射影像学在颈部损伤尸体检验中的应用

多层面计算机断层成像(MSCT)和磁共振成像(MRI)对尸体骨骼系统和软组织损伤的诊断价值等同于传统的尸体解剖,运用在颈部损伤的尸体检验中可以弥补传统尸体解剖的某些不足,在某些特定的环境、腐败、烧焦或具有传染性的尸体检验中,MSCT和MRI联合使用可以作为机械性窒息、挥鞭样损伤、颈椎损伤及颈部血管损伤的可选择的法医学检查手段之一。     

An Overview of 3D Printing in Forensic Science: The Tangible Third-Dimension

There has been a rapid development and utilization of three-dimensional (3D) printing technologies in engineering, health care, and dentistry. Like many technologies in overlapping disciplines, these techniques have proved to be useful and hence incorporated into the forensic sciences. Therefore, this paper describes how the potential of using 3D printing is being recognized within the various sub-disciplines of forensic science and suggests areas for future applications. For instance, the application can create a permanent record of an object or scene that can be used as demonstrative evidence, preserving the integrity of the actual object or scene. Likewise, 3D printing can help with the visualization of evidential spatial relationships within a scene and increase the understanding of complex terminology within a courtroom. However, while the application of 3D printing to forensic science is beneficial, currently there is limited research demonstrated in the literature and a lack of reporting skewing the visibility of the applications. Therefore, this article highlights the need to create good practice for 3D printing across the forensic science process, the need to develop accurate and admissible 3D printed models while exploring the techniques, accuracy and bias within the courtroom, and calls for the alignment of future research and agendas perhaps in the form of a specialist working group.     

膝关节侧副韧带损伤MRI影像诊断的比较研究

目的研究膝关节侧副韧带损伤的MRI诊断与法医学鉴定意义。方法对经手术或临床证实的11例共13条损伤的侧副韧带与12例正常膝关节进行回顾性MRI对比研究。结果正常胫、腓侧副韧带在T1WI和T2WI上均呈扁平条状低信号结构,平均长度分别为6.8cm和5.7cm;13条侧副韧带损伤,单纯胫侧副韧带损伤6条,单纯腓侧副韧带损伤3条,两侧侧副韧带同时损伤2例4条;其中I级侧副韧带损伤5条,II级侧副韧带损伤5条;III级侧副韧带损伤3条;7例(63.6%)出现并发症,其中前交叉韧带损伤3条,后交叉韧带损伤4条,半月板损伤2个。结论MRI能清晰显示膝关节侧副韧带解剖结构,能准确诊断侧副韧带损伤并进行分级,还能发现多种并发症,对法医学鉴定有重要意义。     

紫外光谱成像技术显现潜在油汗混合指印的初步探索

目的研究运用紫外光谱成像技术显现潜在油汗混合指印的可行性和方法。方法使用紫外光谱成像仪获取典型潜在油汗混合指印的光谱影像数据资料,比较不同数据处理软件的分析结果。结果紫外光谱成像技术具有显现潜在油汗指印的能力。结论紫外光谱成像技术能够成功显现非渗透性客体表面潜在油汗混合指印。     

Forensic Radiology Pitfalls: CT Imaging in Gunshot Wounds of the Head

Computed tomography (CT) imaging is increasingly used in emergency departments and trauma services and is being offered as a supplemental tool with autopsy in coroner's and medical examiner's offices throughout the United States. The availability of CT images in lieu of traditional X‐rays for medicolegal autopsies may lead to misinterpretation of images for forensic pathologists who are not familiar with these types of images. Forensic pathologists must become familiar with CT imaging, the basis of CT image formation and how to interpret CT images appropriately. We highlight potential pitfalls of CT image interpretation through two cases of fatal gunshot wounds of the head. Antemortem CT imaging available at the time of autopsy led to discrepancy between the initial image findings and the autopsy due to inexperienced manipulation of the images. With appropriate understanding of CT image interpretation and manipulation, forensic personnel should be able to avoid most sources of misinterpretation.     

Blood aspiration as a vital sign detected by postmortem computed tomography imaging

Blood aspiration is a significant forensic finding. In this study, we examined the value of postmortem computed tomography (CT) imaging in evaluating findings of blood aspiration. We selected 37 cases with autopsy evidence of blood in the lungs and/or in the airways previously submitted to total-body CT scanning. The CT-images were retrospectively analyzed. In one case with pulmonary blood aspiration, biopsy specimens were obtained under CT guide for histological examination. In six cases, CT detected pulmonary abnormalities suggestive of blood aspiration, not mentioned in the autopsy reports. CT reconstructions provided additional data about the distribution and extent of aspiration. In one needle-biopsied case, the pulmonary specimens showed blood in the alveoli. We suggest the use of CT imaging as a tool complementary to traditional techniques in cases of blood aspiration to avoid misdiagnosis, to guide the investigation of lung tissue, and to allow for more evidence-based inferences on the cause of death.     

针刺干预无先兆偏头痛患者的弥散张量成像研究

目的 通过弥散张量成像（diffusion tensor imaging,DTI）技术和纤维束自动定量分析（automated fiber quantification,AFQ）方法探讨无先兆偏头痛患者在针刺干预前后脑白质纤维的变化。方法 纳入无先兆偏头痛患者20例和健康受试者10例,无先兆偏头痛患者进行每周3次、连续4周的针刺干预,干预前后分别进行DTI和T1像扫描,健康受试者不针刺,仅进行1次核磁扫描。比较无先兆偏头痛患者针刺前后以及无先兆偏头痛患者和健康受试者基于AFQ方法的各向异性分数（fractional anisotropy,FA）值。结果 与健康受试者比较,无先兆偏头痛患者右皮质脊髓束、右上纵束部分节点FA值显著减弱（P＜0.05）;与针刺前比较,无先兆偏头痛患者头痛天数及头痛程度显著下降（P＜0.05）,头痛频率下降不显著,无先兆偏头痛患者右皮质脊髓束、右上纵束、左扣带回部分节点FA值显著增强（P＜0.05）。结论 无先兆偏头痛患者存在广泛白质纤维束受损,针刺能促进受损的脑白质纤维恢复。     

CT、MRI在弥漫性轴索损伤法医学鉴定中应用价值分析

目的探讨CT和MRI检查方法在弥漫性轴索损伤(diffuse axonal injury,DAI)法医学鉴定中的应用价值。方法收集26例CT和MRI影像资料齐全的DAI鉴定资料进行回顾性分析,比较CT和MRI两种方法对DAI病灶检出率的差异,分析DAI病灶检出数量与法医学鉴定结果之间的关系。结果 26例经MRI检出DAI病灶787个,经CT检出DAI病灶32个,MRI对DAI病灶的敏感度显著高于CT(P0.01)具有统计学意义。26例DAI鉴定的伤残等级数值与影像学检查发现的病灶数量之间存在负相关(r=-0.908,P0.01)。结论 MRI检查对DAI病灶的检出率较CT检查具有明显优势,可为DAI诊断提供更为准确的依据,在法医临床学鉴定中具有重要的应用价值。