Post-mortem Head Research Articles

Feasibility of Robotic Transorbital Surgery.

The transorbital approach (TOA) facilitates access to pathologies lateral to the optic nerve, a region that is difficult to access with an endonasal approach. In this study, we sought to investigate the feasibility of robotic-assisted surgery in lateral TOA. Six colored-silicon-injected human postmortem heads were prepared for dissection. The DaVinci Xi model was used with a 0-degree camera, 8 mm in diameter. A black diamond microforceps with an 8-mm diameter and 10-mm jaw length was used. The entry point of V1 (superior orbital fissure), V3 (foramen ovale), and posterior root of the trigeminal ganglion were chosen as the surgical targets. The length from the entry opening to each target point was measured. The angles formed between pairs of target points were measured to obtain the horizontal angle (root of the trigeminal ganglion-entry-V1) and the vertical angle (root of the trigeminal ganglion-entry-V3). Dissection was performed on 12 sides (6 specimens). The median distance from the entry point was 55 mm (range 50-58 mm) to the entry point of V1 (superior orbital fissure), 65 mm (range 57-70 mm) to the entry point of V3 (foramen ovale), and 76 mm (range 70-87 mm) to the root of the trigeminal ganglion. Meanwhile, the median of surgical angle between the entry point and the target was 19.1° (range 11.8-30.4°) on the horizontal angle and 16.5° (range 6.2-21.6°) on the vertical angle. This study found that application of lateral TOA in robotic-assisted surgery is premature because of the large size of the tool. However, although the entrance in lateral TOA is narrow, the internal surgical space is wide; this offers potential for design of appropriate surgical tools to allow increase tool usage.

Artificial intelligence-based forensic sex determination of East Asian cadavers from skull morphology

Identification of unknown cadavers is an important task for forensic scientists. Forensic scientists attempt to identify skeletal remains based on factors including age, sex, and dental treatment remains. Forensic scientists commonly consider skull or pelvic shape to evaluate the sex; however, these evaluations require sufficient experience and knowledge and lack objectivity and reproducibility. To ensure objectivity and reproducibility for sex evaluation, we applied a gated attention-based multiple-instance learning model to three-dimensional (3D) skull images reconstructed from postmortem head computed tomography scans. We preprocessed the images, trained with 864 training data, validated the model with 124 validation data, and evaluated the performance of our model in terms of accuracy with 246 test data. Furthermore, three forensic scientists evaluated the 3D skull images, and their performances were compared with those of the model. Our model showed an accuracy of 0.93, which was higher than that of the forensic scientists. Our model primarily focused on the entire skull owing to visualization but focused less on the areas often investigated by forensic scientists. In summary, our model may serve as a supportive tool to identify cadaver sex based on skull shape. Further studies are required to improve the model’s performance.

Refining the Anatomy of Percutaneous Trigeminal Rhizotomy: A Cadaveric, Radiological, and Surgical Study.

Percutaneous trigeminal rhizotomy (PTR) is a widely used procedure for trigeminal neuralgia. However, comprehensive analyses that combine anatomic, radiological, and surgical considerations are rare. To present high-quality anatomic dissections and radiological studies that highlight the technical nuances of this procedure. Six silicon-injected postmortem heads underwent PTR. The surgical corridors were dissected, and the neurovascular relationships were studied. In addition, 20 dried human skulls and 50 computed tomography angiography and MRI scans were collected to study the anatomic relationships for a customized puncture corridor. The PTR corridor was divided into 3 segments: the buccal segment (length, 34.76 ± 7.20 mm), the inferior temporal fossa segment (length, 42.06 ± 6.92 mm), and the Meckel cave segment (length, 24.75 ± 3.34 mm). The puncture sagittal (α) and axial (β) angles measured in this study were 38.32° ± 4.62° and 19.13° ± 2.82°, respectively. The precondylar reference line coincided with the foramen ovale in 75% of the computed tomography angiography scans, and the postcondylar line coincided with the carotid canal in 70% of the computed tomography angiography scans; these lines serve as the intraoperative landmarks for PTR. The ovale-carotid-pterygoid triangle, delineated by drawing a line from the foramen ovale to the carotid canal and the lateral pterygoid plate, is a distinguished landmark to use for avoiding neurovascular injury during fluoroscopy. Knowledge of the anatomic and radiological features of PTR is essential for a successful surgery, and a customized technical flow is a safe and effective way to access the foramen ovale.

Highly Effective Frontal Stunning Procedure Using a Pneumatic Penetrating Captive Bolt in Water Buffaloes

An effective frontal stunning procedure in water buffaloes was assessed using a pneumatic penetrating captive bolt (PPCB) with high air pressure. The study contemplated two phases; first, 352 buffaloes and 168 post-mortem heads were evaluated to determine the most effective anatomical site for stunning. Then, the second phase (n = 182) was used to validate the stunning procedure at the discovered anatomical site in the first phase, which was located 8 cm dorsal above the middle of the forehead on an "X" formed between the eyes and the base of the contralateral horns, and 2 cm lateral, avoiding the midline, where the skull tended to narrow. A total of 95.1% of buffaloes received effective stunning at the first shot with evidence of the presence of collapse, absence of rhythmic breathing, and absence of ocular reflexes (corneal and palpebral). There were no differences in the stunning efficacy by sex, breed, or skull thickness. These findings demonstrated that stunning with a PPCB at pressures of 1379-1516.8 KPa (200-220 pounds per square inch (psi)) in the site reported here produces a highly effective stunning at the first shot in water buffaloes.

Microsurgical anatomy of the dorsal clinoidal space: implications for endoscopic endonasal parasellar surgery.

The clinoidal venous space dorsal to the internal carotid artery (ICA) has not been well studied given its inaccessibility due to obstruction by the ICA during transcranial surgery. The evolution of endoscopic endonasal surgery has provided a new perspective into the clinoidal space and a new route for paraclinoidal lesions. Understanding the dorsal clinoidal space (DCS) is vital in planning and performing endoscopic endonasal surgery in the parasellar region. A detailed and precise description of the DCS from the endonasal perspective has not yet been provided. The authors' goal in this study was to delineate the microsurgical anatomy of the DCS from an endoscopic endonasal perspective, emphasizing its surgical implications when treating invasive pituitary adenomas and other parasellar lesions. An endoscopic endonasal transsellar approach was performed in 15 silicone-injected postmortem heads. Afterward, the sellar region was dissected through a transcranial approach using magnification ×3 to ×40 microscopy. The osseous, dural, and arterial relationships of the DCS and its architecture were investigated. The DCS's length, width, and depth were measured and its anatomical variations recorded. The DCS was identified in 90% of the specimens, and in most cases, its shape was a narrow rectangular pyramid, with its base oriented toward the sphenoid sinus and its apex toward the posterior clinoid process. It is delimited superiorly by the distal ring, inferiorly by the medial aspect of the proximal dural ring or caroticoclinoid ligament, laterally by the clinoidal ICA, and medially by the superior continuation of the medial wall of the cavernous sinus. The width, height, and length of the DCS were 4 ± 1, 4.5 ± 1.5, and 7 ± 2 mm, respectively. A fenestrated caroticoclinoid ligament is a potential route for tumor invasion from the cavernous sinus into the DCS. This report provides important anatomical descriptions of the DCS from endoscopic endonasal and transcranial perspectives that may facilitate the space's safe exposure for the removal of invasive adenomas, increasing total resection rates and minimizing the risk of injury to neurovascular structures.

Microsurgical anatomy and the importance of the petrosal process of the sphenoid bone in endonasal surgery.

The petrosal process of the sphenoid bone (PPsb) is a relevant skull base osseous prominence present bilaterally that can be used as a key surgical landmark, especially for identifying the abducens nerve. The authors investigated the surgical anatomy of the PPsb, its relationship with adjacent neurovascular structures, and its practical application in endoscopic endonasal surgery. Twenty-one dried skulls were used to analyze the osseous anatomy of the PPsb. A total of 16 fixed silicone-injected postmortem heads were used to expose the PPsb through both endonasal and transcranial approaches. Dimensions and distances of the PPsb from the foramen lacerum (inferiorly) and top of the posterior clinoid process (PCP; superiorly) were measured. Moreover, anatomical variations and the relationship of the PPsb with the surrounding crucial structures were recorded. Three representative cases were selected to illustrate the clinical applications of the findings. The PPsb presented as a triangular bony prominence, with its base medially adjacent to the dorsum sellae and its apex pointing posterolaterally toward the petrous apex. The mean width of the PPsb was 3.5 ± 1 mm, and the mean distances from the PPsb to the foramen lacerum and the PCP were 5 ± 1 and 11 ± 2.5 mm, respectively. The PPsb is anterior to the petroclival venous confluence, superomedial to the inferior petrosal sinus, and inferomedial to the superior petrosal sinus; constitutes the inferomedial limit of the cavernous sinus; and delimits the upper limit of the paraclival internal carotid artery (ICA) before the artery enters the cavernous sinus. The PPsb is anterior and medial to and below the sixth cranial nerve, forming the floor of Dorello's canal. During surgery, gentle mobilization of the paraclival ICA reveals the petrosal process, serving as an accurate landmark for the location of the abducens nerve. This investigation revealed details of the microsurgical anatomy of the PPsb, its anatomical relationships, and its application as a surgical landmark for identifying the abducens nerve. This novel landmark may help in minimizing the risk of abducens nerve injury during transclival approaches, which extend laterally toward the petrous apex and cavernous sinus region.

Validation of Muscle Fiber Architecture of the Human Tongue Revealed by Diffusion Magnetic Resonance Imaging With Histology Verification.

The goal of this study is to validate the muscle architecture derived from both ex vivo and in vivo diffusion-weighted magnetic resonance imaging (dMRI) of the human tongue with histology of an ex vivo tongue. dMRI was acquired with a 200-direction high angular resolution diffusion imaging (HARDI) diffusion scheme for both a postmortem head (imaged within 48 hr after death) and a healthy volunteer. After MRI, the postmortem head was fixed and the tongue excised for hematoxylin and eosin (H&E) staining and histology imaging. Structure tensor images were generated from the stained images to better demonstrate muscle fiber orientations. The tongue muscle fiber orientations, estimated from dMRI, were visualized using the tractogram, a novel representation of crossing fiber orientations, and compared against the histology images of the ex vivo tongue. Muscle fibers identified in the tractograms showed good correspondence with those appearing in the histology images. We further demonstrated tongue muscle architecture in in vivo tractograms for the entire tongue. The study demonstrates that dMRI can accurately reveal the complex muscle architecture of the human tongue and may potentially benefit planning and evaluation of oral surgery and research on speech and swallowing.

The Smith-Robinson Approach to the Subaxial Cervical Spine: A Stepwise Microsurgical Technique Using Volumetric Models From Anatomic Dissections.

The Smith-Robinson1 approach (SRA) is the most widely used route to access the anterior cervical spine. Although several authors have described this approach, there is a lack of the stepwise anatomic description of this operative technique. With the advent of new technologies in neuroanatomy education, such as volumetric models (VMs), the understanding of the spatial relation of the different neurovascular structures can be simplified. To describe the anatomy of the SRA through the creation of VMs of anatomic dissections. A total of 4 postmortem heads and a cervical replica were used to perform and record the SRA approach to the C4-C5 level. The most relevant steps and anatomy of the SRA were recorded using photogrammetry to construct VM. The SRA was divided into 6 major steps: positioning, incision of the skin, platysma, and muscle dissection with and without submandibular gland eversion and after microdiscectomy with cage positioning. Anatomic model of the cervical spine and anterior neck multilayer dissection was also integrated to improve the spatial relation of the different structures. In this study, we review the different steps of the classic SRA and its variations to different cervical levels. The VMs presented allow clear visualization of the 360-degree anatomy of this approach. This new way of representing surgical anatomy can be valuable resources for education and surgical planning.

Segmental hair analysis of olanzapine and N-desmethyl-olanzapine in postmortem hair from mentally ill patients by LC–MS/MS

Hair analysis is a useful tool for establishing long-term drug intake. Segmental analysis, in particular, where the hair is cut into defined segments, can potentially provide a calendar of patients’ drug intake as drugs are incorporated into the growing hair through the bloodstream with an average growth rate of 1 cm per month. Forensic investigations of hair require knowledge of typical concentrations of common pharmaceuticals in hair, which are rarely reported. The aim of this study was to provide values for olanzapine and N-desmethyl-olanzapine concentrations in postmortem hair from chronic olanzapine consumers to contribute to the establishment of a reference interval for this drug. We analyzed postmortem head hair samples from 37 suspected mentally ill patients, who were part of the SURVIVE population, a Danish national autopsy-based study. Each sample was cut into 1 cm segments, and up to six segments, corresponding to up to six months of hair growth prior to death, were analyzed depending on the hair length. The hair extracts were analyzed by liquid chromatography tandem mass spectrometry. Olanzapine and N-desmethyl-olanzapine were added to a published and validated method. The 37 patients were 12 females and 25 males aged 25–81 years. Their hair colors varied from blond to black, with the majority brown, thus no trend could be discerned from the hair colors. Drugs other than olanzapine were found in all cases except one, and illicit drugs were found in the hair samples of 38 % of the cases. We report olanzapine concentrations ranging from 0.005–20.9 ng/mg (median 0.128 ng/mg) and N-desmethyl-olanzapine concentrations from 0.027 to 0.187 ng/mg (median 0.068 ng/mg) for all 141 analyzed segments. Metabolite-to-drug ratios ranged from 0.010 to 3.31 (median 0.590). Dose calculations based on prescription pick-up demonstrated no correlation with the concentrations in hair, but olanzapine concentrations in the proximal hair segment correlated significantly with olanzapine concentrations in postmortem blood. Olanzapine concentrations decreased considerably from the proximal to distal segments, emphasizing the importance of reporting the length of the measured hair when reporting drug concentrations in hair. This study can contribute to the establishment of a reference interval for olanzapine and N-desmethyl-olanzapine concentrations in hair by reporting concentrations in hair from chronic consumers.

A simple method for semi-automatic readjustment for positioning in post-mortem head computed tomography imaging

Abstract The purpose of this study is to evaluate the usefulness of a simple method for readjustment of positioning in post-mortem (PM) head computed tomography (CT) imaging. Two hundred and twenty-five autopsied cases were used to test our proposed method. The coordinates of 5 landmarks on axial planes in PM head CT images were determined manually to calculate Yaw, Pitch, and Roll angles for the sake of readjustment. A radiologist and a forensic pathologist evaluated the readjustment by mutual agreement. Intraclass correlation coefficients (ICCs) for Yaw, Pitch, and Roll angles were measured for 3 operators. Similarity in AM and PM images after the readjustment was tested for 18 cases to evaluate the usefulness of the readjustment in personal identification for forensic cases. If similarity of the same person showed the highest value among all combinations in 18 cases, it was regarded as the correct identification. The processing time of our readjustment was limited to within 2 min per case. The orbitomeatal line (OML) was included in a single axial plane in 96.4% (217/225) of the cases after the readjustment. Reproducibility for determining landmarks showed acceptable ICC. Moreover, rank-one identification rate before and after readjustment were 16.7% (3/18) and 88.9% (16/18), respectively. Thus, our method for semi-automated readjustment exhibited potential usefulness in forensic cases. A simple method for semi-automatic readjustment would be a useful tool for post-mortem CT imaging with high reproducibility and a short processing time.

Post-mortem X-ray computed tomography (PMCT) identification using ante-mortem CT-scan of the sphenoid sinus

PurposeTo evaluate forensic identification of individuals through visual comparison of sphenoid sinus anatomical configuration using ante- and post-mortem CT-scans. Method and materialsAnte- and post-mortem head CT-scan of 33 individuals were retrospectively collected. Ten head CT-scans were randomly selected from various neurological contexts and added to the ante-mortem group. Ten other head CT-scans were randomly selected from our post-mortem PACS and added to the post-mortem group. These CT-scans were assigned into 2 groups for analysis: an ante-mortem group (33 + 10) and a post-mortem group (33 + 10). For ethics and to avoid identification bias, CT-scans were anonymized – not showing any head structure but only sphenoid sinuses. An anatomical based classification system using the sphenoid sinuses anatomical variations was created according to anatomical and surgical literature. This classification was used by readers to identify in two different steps a maximum of matched and then unmatched scans. ResultsThe first reader had a sensitivity of 100% [CI: 89.4%–100%] and a specificity of 100% [CI: 99.8%–100%]. Sensitivity and specificity were respectively 93.9% [CI: 79.8%–99.3%] and 99.9% [CI: 99.6%–100%] for the second reader. Positive and negative predictive values were respectively 100% [CI: 89.4%–100%] and 100% [CI: 99.8%–100%] for the first reader. Positive and negative values were respectively 96.9% [CI: 83.8%–99.9%] and 99.9% [CI: 99.7%–100%] for the second reader. Inter-reader variability was estimated by Cohen's kappa and an excellent agreement was found. ConclusionWe reported an excellent validity and reliability of subjective visual comparison of ante- and post-mortem CT-data using an anatomical based classification of the sphenoid sinus.

Superior Canal Dehiscence: A Comparative Postmortem Multislice Computed Tomography Study.

ObjectiveSuperior canal dehiscence is defined by missing bony coverage of the superior canal against the middle cranial fossa. The gold standard in diagnosis is high-resolution computed tomography (CT). A false-positive CT scan, identifying a dehiscence when one is not present, could lead to unnecessary surgical therapy. This study aims to compare postmortem CT scans with autopsy findings with regard to superior canal dehiscence.Study DesignPostmortem study.SettingTertiary referral center.Subjects and MethodsTwenty-two nontraumatic death cases within a 3-month period (January to March 2017) were included with 44 temporal bones. Each body underwent postmortem head CT prior to medicolegal autopsy. The middle fossa floor was exposed, and if present, the superior semicircular canal dehiscence was identified and measured. In each case, 3 comparable photographs were taken during the autopsy (left temporal bone, right temporal bone, overview).ResultsAutopsy findings revealed bony dehiscences in 11% of the temporal bones, whereas CT scan revealed bony dehiscences in 16%. The length of the dehiscences were longer when measured by CT imaging.ConclusionThe diagnosis of superior canal dehiscence syndrome requires high-resolution CT with clinical symptoms and physiologic evidence of a third mobile window. Our study underlines a mismatch between multislice CT imaging in the coronal plane and the presence of a dehiscence on autopsy.

Comparative radiologic identification with standardized single CT images of the paranasal sinuses—Evaluation of inter-rater reliability

The aim of this study was to assess the reproducibility of a standardized image for personal identification (SIPI), used in the comparative analysis of paranasal sinuses, and test the effect of inaccurate reformation of the SIPI on suitability for comparative identification.Five raters with different professional backgrounds independently reformatted SIPIs from ten post-mortem head CTs. Inter-rater, intra-rater agreement as well angular deviations between reformatted SIPI images and reference SIPI images were calculated. Second, raters assessed the suitability of 70 accurately and inaccurately reformatted SIPIs for identification with a 4-point Likert scale. Inter-rater agreement as well as levels of significance regarding image suitability were calculated.Inter-rater agreement regarding reproducibility of SIPI reformation was excellent (inter-rater correlation coefficient (ICC) 0.9995, intra-rater ICC 0.9983). Deviation between the angular dimensions of the reformatted SIPIs and the reference SIPIs was ≤1° in 94% of all 300 measurements. Inter-rater agreement regarding the effect of inaccurate SIPI reformation on suitability for comparative identification was fair (ICC 0.6809). There was no statistically significant difference between raters’ evaluation of image suitability (p=0.9755).This study shows that the standardized image for personal identification can be accurately reformatted by different raters with varying professional backgrounds. In addition, raters agree that inaccurately reformatted SIPIs are still suitable for comparative identification in the majority of cases.

Determination of cocaine and its derivatives in hair samples by liquid phase microextraction (LPME) and gas chromatography–mass spectrometry (GC–MS)

Hair testing is a recognized approach when it comes to accessing historical drug use. According to the World Drug Report of United Nations Office on Drugs and Crime (UNODC) 2015, Brazil is the largest cocaine (COC) market in South America. New analytical methodologies to detect crack/cocaine analytes in hair samples are highly desirable. Here, a method consisting of a liquid-phase microextraction (LPME) as a clean-up step, followed by gas chromatography–mass spectrometry (GC–MS) analysis has been proposed. The new validated method consisted of a washing step; an overnight incubation with methanol and a quick derivatization with butylchloroformate. Once derivatized, the samples were then submitted to the LPME procedure. Limits of detection (LoD) and quantitation (LoQ) obtained were of 0.1 and 0.5ng/mg for COC 0.4 and 0.5ng/mg for anhydroecgonine methyl ester (AEME); 0.03 and 0.05 for cocaethylene (CE), respectively and 0.05ng/mg for both LoD and LoQ for benzoylecgonine (BZE). All calibration curves were linear over the scope applied, from LoQ up to 20ng/mg, with a r2>0.99. Precision and accuracy assays showed acceptable %RSD values, according to international guidelines. Twelve postmortem head hair samples stemming from the Institute of Legal Medicine of Sao Paulo (IML-SP) have been analyzed, from which seven have shown to be positive for COC (0.75–>20ng/mg) and BZE (0.1–>20ng/mg). Apart from COC’s main metabolite, four samples were also positive for CE (0.1–3.9ng/mg) and three samples for AEME (0.5–4.9ng/mg). To conclude, the LPME technique together with GC–MS analysis have shown promising results and were able to meet the demand of the laboratory of analyzing postmortem hair samples to look for all four analytes.

Interpretation of postmortem head computed tomography for non-traumatic in-hospital deaths by non-radiologists: a preliminary study.

PurposePostmortem computed tomography (PMCT) has recently become important to clarify the cause of death in forensic medicine. It has also been proven to be useful for in-hospital deaths to a certain extent when interpreted by radiologists. However, accuracy of the interpretations of PMCT by non-radiologists remains to be elucidated. Nevertheless, they are often required to write death certificates based on the findings of PMCT in the absence of radiologists in Japan. We compared the interpretations of postmortem head CT (PMCT-H) by non-radiologists with the autopsy findings.MethodsThis study included 13 patients who underwent both brain dissection at autopsy and PMCT between June 2011 and December 2014. All cases were non-traumatic in-hospital deaths. Interpretation of PMCT was performed by the clinicians in charge of the patients, not by radiology experts.ResultsThe patients were first examined with PMCT and then autopsies were performed. Ten out of 13 cases were confirmed to have no lesions in the cranial cavity by both PMCT-H and autopsy. Two cases were diagnosed with intracranial hemorrhage (intracerebral and/or subarachnoid hemorrhage) and one with recurrent malignant lymphoma by both the clinicians and the pathologists. Intracranial hemorrhages were thought to be the direct causes of mortality of the two patients, and recurrent malignant lymphoma was considered to be one of the cardinal findings of the cancer death. There were no discrepancies between PMCT-H and autopsy findings.ConclusionsThe interpretations of PMCT-H by non-radiologists were completely the same as the autopsy findings regarding the non-traumatic in-hospital deaths in this study. It is premature to draw a definitive conclusion at present, but PMCT-H might be as effective as autopsy not only for those lesions described above but also for no remarkable changes in the brain. There has been no report on such a comparison. We believe further verification of the validity of interpretation of PMCT by non-radiologists is worthwhile in terms of death certificates made out in the absence of radiology experts and pathologists.

SU‐F‐I‐46: Optimizing Dose Reduction in Adult Head CT Protocols While Maintaining Image Quality in Postmortem Head Scans

Purpose:To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality.Methods:Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced‐dose protocols with varying combinations of reduced tube current, reduced rotation time, and increased detectors with CTDIvol ranging from 38.2 to 65.6 mGy. Organ doses were directly measured with 21 OSL dosimeters placed on the surface and implanted in the head by a neurosurgeon. Two neuroradiologists assessed grey‐white matter differentiation, fluid space, ventricular size, midline shift, brain mass, edema, ischemia, and skull fractures on a three point scale: (1) Unacceptable, (2) Borderline Acceptable, and (3) Acceptable.Results:For the standard scan, doses to the skin, lens of the eye, salivary glands, thyroid, and brain were 37.55 mGy, 49.65 mGy, 40.67 mGy, 4.63 mGy, and 27.33 mGy, respectively. Two cadavers had cerebral edema due to changing dynamics of postmortem effects, causing the grey‐white matter differentiation to appear less distinct. Two cadavers with preserved grey‐white matter received acceptable scores for all image quality features for the protocol with a CTDIvol of 57.3 mGy, allowing organ dose savings ranging from 34% to 45%. One cadaver allowed for greater dose reduction for the protocol with a CTDIvol of 42 mGy.Conclusion:Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. Radiologists at our institution accepted scan protocols acquired with lower scan parameters, with CTDIvol values closer to the American College of Radiology's (ACR) Achievable Dose level of 57 mGy.

Atlanto-axial rotatory subluxations in postmortem CT: Radiologists be aware of a common pitfall

The aim of the present study was to determine the frequency of atlanto-axial rotatory subluxations (AARS) in multi detector computed tomography (MDCT) performed on human corpses for forensic purposes and to investigate whether these are a physiological postmortem finding or indicate a trauma to the neck region.80 forensic cases examined with MDCT from November 2003 to March 2007 were included in the study. The study was approved by the regional ethics committee. For each case volumes were rendered and investigated with reference to suspected AARS and any other anomalies of the head and neck region. The rotation of the head as well as in the atlanto-axial joint were measured and occurring AARS were judged according Fielding's classification. The finding of AARS was correlated to case criteria such as postmortem head rotation, sex, age, cause of death, time since death and further autopsy results. Statistical analysis was performed using Fisher's exact test, Wilcoxon's rank sums test and Chi-square test with Pearson approximation.70% (n=56) of the cases included in the study presented with an AARS. A strong correlation (P<.0001) between suspected AARS and postmortem head rotation was found. Two cases presented with an atlanto-axial rotation greater than the head rotation. One showed an undiscovered lateral dislocation of the atlas, and one an unfused atlas-ring. There was no correlation to any further investigated case criteria. Ipsilateral AARS with head rotation alone does not indicate trauma to the neck.PmCT can substantially support forensic examinations of the skeleton, especially in body regions, which are elaborate to access at autopsy, such as the cervical spine. Isolated AARS (Fielding type I) on pmCT is usually a normal finding associated with ipsilateral head rotation.

Common and Expected Postmortem CT Observations Involving the Brain: Mimics of Antemortem Pathology

Postmortem imaging with CT or MR is emerging as an effective technique to augment forensic autopsy. Expected findings on postmortem imaging of the brain may mimic pathologic processes in the living brain, leading to potential misdiagnosis. The purpose of this study is to describe the array of CT findings that can be expected to be present within the brain after death. A retrospective review was performed using an anonymized data base of 33 postmortem head CTs with no evidence of trauma to the face or scalp. Head CTs were assessed for 1) loss of gray-white differentiation, 2) effacement of the ventricles and cisterns, 3) postmortem intravascular blood distribution, 4) presence of intracranial or intravascular air, and 5) an irregular appearance of the falx. Imaging findings were correlated with autopsy findings. Visualization of the basal ganglia was noted in 30 (91%) subjects, and the cortical ribbon was appreciated in 14 (42%). The ventricles and cisterns were effaced in 19 (58%) cases. An "expected postmortem blood distribution" was seen in 27 (82%) instances. Intravascular air was present in 14 cases (42%). A "lumpy" falx was present in 20 cases (61%). In 4 cases of subdural or subarachnoid hemorrhage noted on autopsy, but not on CT, retrospective review confirmed that a true discrepancy between the radiology and pathology findings persisted. Recognition of expected postmortem patterns is required before pathology can be accurately diagnosed. A limitation of CT virtual autopsy is the possibility of missing small blood collections.