Dilatation of the heart on postmortem computed tomography (PMCT): comparison with live CT

PURPOSE: To delineate cardiac structures on postmortem computed tomography (PMCT) and quantitatively to prove dilatation of the heart after death. MATERIALS AND METHODS: Our subjects were 50 PMCT of non-traumatic deaths and 50 CT of living persons (live CT). We measured maximal and minimal diameters of the superior vena cava (SVC) at three levels (upper, middle, and lower), the inferior vena cava (IVC), pulmonary artery (PA), pulmonary vein (PV), right atrium (RA), and left atrium (LA). Then the product of maximal by minimal diameter and the eccentricity were calculated. RESULTS: The maximal and minimal diameters of the heart were significantly longer than those on live CT except for 1) the maximal diameter of the SVC at the upper level and 2) the maximal diameter of the PA. All of the products of maximal by minimal diameter on PMCT were significantly larger than those on live CT. All of the eccentricities decreased significantly after death except LA. CONCLUSION: The heart is dilated on PMCT, and the right side of it dilates toward a round shape.     

Cardiovascular gas on non-traumatic postmortem computed tomography (PMCT): the influence of cardiopulmonary resuscitation

PURPOSE: The purpose of this study was to investigate the causes of cardiovascular gas (CVG) detected on non-traumatic postmortem computed tomography (PMCT). MATERIALS AND METHODS: PMCT was performed on 247 subjects within two hours of non-traumatic death, including 228 patients who had undergone cardiopulmonary resuscitation (CPR) and 19 patients who had not. We evaluated the incidence and distribution of CVG in four areas of the heart, namely, 1) the upper course of the right atrium (UC-RA), 2) the right atrium, 3) the right ventricle, and 4) the left heart (left atrium, left ventricle, and aorta). RESULTS: CVG was observed in 163 (71%) of the 228 patients who underwent CPR. In those 163 patients, we detected CVG in the UC-RA (103 patients), right atrium (81 patients), right ventricle (94 patients), and left heart (5 patients). Nineteen patients who received no CPR showed no CVG. CONCLUSION: CVG on non-traumatic PMCT is mainly caused by CPR, which is characterized by venous catheterization that permits possible air inflow and by pneumatization of dissolved gas in the blood as a result of cardiac massage.     

Hepatic portal venous gas and hyper-dense aortic wall as postmortem computed tomography finding

Postmortem computed tomography (PMCT) is useful for diagnosis of cause of death not only by emergency physicians but also medical examiners or police surgeons conducting postmortem studies. However, postmortem biological conditions are quite different from those in the living body. Hepatic portal venous gas (HPVG) and a hyperdense aortic wall (HDAW) are often found by PMCT, although no significant autopsy findings are evident in the liver or aorta. In this study we compared the findings of PMCT with those obtained at autopsy, and discussed the cause of these PMCT features. PMCT was conducted in 12 autopsy cases, comprising eight cases of natural death and four of unnatural death. HPVG was seen in five cases and HDAW in seven. In the cases showing HPVG, visceral abdominal injury, bowel distention or acute circulatory dysfunction was found at autopsy. In the cases showing HDAW, atherosclerosis or an increase in blood viscosity due to dehydration or postmortem changes was evident. Although the precise causes of these PMCT findings are not completely clear, the changes evident at autopsy provide some clues.     

Greater thickness of the aortic wall on postmortem computed tomography compared with antemortem computed tomography: the first longitudinal study

Objectives

To evaluate postmortem changes of the aorta on postmortem computed tomography (CT) in comparison with those on antemortem CT obtained in the same patients.

Materials and Methods

We studied 57 consecutive patients who had undergone antemortem CT, postmortem CT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. Postmortem CT was performed within 20 h after death, followed by pathological autopsy. Pathological autopsy confirmed the absence of cardiovascular disease such as aortic aneurysm, aortic dissection, or Marfan syndrome in all patients. Aortic wall thickness and aortic cross-sectional areas were measured on both antemortem CT and postmortem CT. Difference in aortic wall thickness between antemortem CT with and without contrast medium, and between antemortem CT and postmortem CT, and in cross-sectional area of the aortic wall between antemortem CT and postmortem CT was evaluated statistically.

Results

No significant difference in aortic wall thickness was observed on antemortem CT in comparison of contrasted and non-contrasted images. The aortic wall was significantly thicker on postmortem CT than on antemortem CT (p?Conclusion This is the first longitudinal study to confirm greater thickness of the aortic wall on postmortem images compared with antemortem images in the same patients and to show no change in cross-sectional area of the aortic wall between before and after death.     

Postmortem computed tomographic (PMCT) findings of pericardial effusion due to acute aortic dissection

PURPOSE: To describe the appearance of pericardial effusion in deceased acute aortic dissection patients using postmortem computed tomography (PMCT). MATERIALS AND METHODS: PMCT examinations were performed within 2 hours of death in 30 patients with pericardial effusion due to aortic dissection who arrived at our hospital in a state of cardiopulmonary arrest. RESULTS: Pericardial effusion in 18 of 30 patients (60%) showed double concentric rings on PMCT with striking differences in density, a low-density outer ring along the pericardium and a high-density inner ring on the epicardial surface (hyperdense armored heart). Pericardial effusion in two patients (7%) showed a high-density fluid level (hypostasis). Pericardial effusion in the remaining 10 patients (33%) showed no such stratification. CONCLUSION: A "hyperdense armored heart" is the most frequently seen PMCT finding in deceased cases of pericardial effusion due to acute aortic dissection.     

Postmortem computed tomographic (PMCT) and postmortem magnetic resonance imaging (PMMRI) demonstration of fatal massive retroperitoneal hemorrhage caused by abdominal aortic aneurysm (AAA) rupture

We report a case of fatal massive retroperitoneal homorrhage caused by the rupture of an abdominal aortic aneurysm (AAA) in which postmortem computed tomography (PMCT) and postmortem magnetic resonance imaging (PMMRI) provided clear delineation. In this case, the autopsy imaging system using PMCT and PMMRI was useful as a screening method to determine the cause of death as AAA rupture and became a guide for the subsequent autopsy.     

New pitfalls of high-density postmortem computed tomography

An 80-year-old female was transferred to the hospital due to a traffic accident. Multiple cranial bone fractures with intracranial hemorrhage and intracranial air were detected. Despite treatment, the patient died after 6 h. Twenty-one hours after the patient died, her whole body was scanned by postmortem CT, and a region of high density was detected within the left putamen. The autopsy revealed a cerebral contusion and multiple skull base fractures. Moreover, superabsorbent polymers (SAPs) were found within the left lateral ventricle and adjacent to the putamen, which appeared as a high-density lesion on postmortem CT at the left putamen, where the SAPs were compacted. Both ante- and postmortem conditions should be considered to prevent misdiagnoses based only on postmortem CT.     

Differentiation of hemopericardium due to ruptured myocardial infarction or aortic dissection on unenhanced postmortem computed tomography

The aim of the study was to evaluate unenhanced postmortem computed tomography (PMCT) in cases of non-traumatic hemopericardium by establishing the sensitivity, specificity and accuracy of diagnostic criteria for the differentiation between aortic dissection and myocardial wall rupture due to infarction. Twenty six cases were identified as suitable for evaluation, of which ruptured aortic dissection could be identified as the underlying cause of hemopericardium in 50% of the cases, and myocardial wall rupture also in 50% of the cases. All cases underwent a PMCT and 24 of the cases also underwent one or more additional examinations: a subsequent autopsy, or a postmortem magnetic resonance (PMMR), or a PMCT angiography (PMCTA), or combinations of the above. Two radiologists evaluated the PMCT images and classified each case as “aortic dissection”, “myocardial wall rupture” or “undetermined”. Quantification of the pericardial blood was carried out using segmentation techniques. 17 of 26 cases were correctly identified, either as aortic dissections or myocardial ruptures, by both readers. 7 of 13 myocardial wall ruptures were identified by both readers, whereas both readers identified correctly 10 of 13 aortic dissection cases. Taking into account the responses of both readers, specificity was 100% for both causes of hemopericardium and sensitivity as well as accuracy was higher for aortic dissections than myocardial wall ruptures (72.7% and 87.5% vs 53.8% and 75% respectively). Pericardial blood volumes were constantly higher in the aortic dissection group, but a statistical significance of these differences could not be proven, since the small count of cases did not allow for statistical tests. This study showed that diagnostic criteria for the differentiation between ruptured aortic dissection and myocardial wall rupture due to infarction are highly specific and accurate.     

Imaging of aortic dissection by helical computed tomography (CT)

Aortic dissection is the most frequent cause of aortic emergency, and its outcome is still frequently fatal. The management of this pathology has changed with the development of endovascular means. Nowadays, imaging modalities are helpful in management decision-making by providing information such as identification of entry tears along the aorta and involvement of the visceral branches of the abdominal aorta. Multi-slice CT scanning now appears to be the modality of choice for complete examination of the entire aorta. We review the parameters of image acquisition and contrast injection; appearances on CT of acute and chronic dissection are illustrated. Diagnostic pitfalls in CT imaging of acute dissection are discussed. Imaging of the post-surgical aorta and of chronic dissection is outlined. Intra-mural hematoma and penetrating aortic ulcer are subtypes of aortic dissection, and their appearances on CT scanning are also presented.     

New identification possibilities with postmortem multislice computed tomography

Historically, radiographical identification has been done by comparing conventional antemortem and postmortem X-ray images. The advent of new technologies such as multislice computed tomography (MSCT) is making traditional antemortem examination increasingly less frequent. The authors present the results of MSCT study of 35 corpses, which demonstrated features potentially useful for identification purposes in ten cases. These features, which relate to abnormalities of postcranial bone as well as of the internal organs, are presented. Attempts were made to find any antemortem X-rays or MSCTs on the cases described to compare the two antemortem and postmortem images. Although antemortem imaging was recovered for only two cases (one case with a skeletal abnormality and one case with a visceral abnormality), it permitted for both cases the comparison of antemortem and postmortem MSCTs. Presented at the XXth Congress of International Academy of Legal Medicine, Budapest, Hungary, August 2006.     

Vascular measurement changes observed using postmortem computed tomography

Purpose

Postmortem vascular changes were quantitatively analyzed in the aorta and vena cava and compared with antemortem findings as a basis for distinguishing between normal postmortem changes and pathological changes.

Materials and methods

Whole-body computed tomography (CT) was performed on 12 individuals before and after death. The scans, performed at seven levels (five for the aorta, two for the vena cava) within the vasculature, allowed various measurements to be made on the same individual before and after death.

Results

Postmortem long-axis diameter, short-axis diameter, and the square of the radius of the aorta were 79.2–85.0 % (mean 81.3 %), 55.6–80.0 % (68.0 %), and 48.5–71.4 % (60.8 %) of the antemortem measurements, respectively. The ante- and postmortem measurements of the long and short axes and the caliber of the aorta were statistically different (p < 0.05). The superior vena cava (SVC) was increased in size: the short-axis diameter and the square of the radius were both statistically different after death. None of the measured parameters of the inferior vena cava (IVC) changed significantly following death.

Conclusion

In postmortem images, the aortic diameter decreased and changes in the size and shape of the SVC were noted. The IVC did not exhibit significant postmortem changes.     

Evaluation of the mediastinal-thoracic volume ratio on postmortem computed tomography

International Journal of Legal Medicine - The aim of this study was to measure the mediastinal-thoracic volume ratio (CTR_VOL) on PMCT as a more accurate version of traditional CTR, in order to...     

The importance of post-mortem computed tomography (PMCT) in confrontation with conventional forensic autopsy of victims of motorcycle accidents

Since traffic accidents are an important problem in forensic medicine, there is a constant search for new solutions to help with an investigation process in such cases. In recent years there was a rapid development of post-mortem imaging techniques, especially post-mortem computed tomography (PMCT). In our work we concentrated on a potential advantage of PMCT in cases of motorcycle accident fatalities. The results of forensic autopsy were compared with combined results of the autopsy and PMCT to check in which areas use of these two techniques gives statistically important increase in number of findings. The hypothesis was confirmed in case of pneumothorax and fractures of skull, spine, clavicle, scapula, lower leg bones. As for majority of other bone fractures locations and brain injures there were single cases with pathologies visible only in PMCT, but too few to reach expected level of p-value. In case of injuries of solid organs and soft tissues statistical analysis did not confirmed any advantage of unenhanced PMCT use. On the whole it has been shown that PMCT used as an adjunct to forensic autopsy can cause an increase in information about vitally important regions in case of motorcycle accident fatalities.     

Quantitative analysis of brain edema and swelling on early postmortem computed tomography: comparison with antemortem computed tomography

Purpose

The aim of this study was quantitatively to analyze brain edema and swelling due to early postmortem changes using computed tomography (CT) scans of the head.

Materials and methods

Review board approval was obtained, and informed consent was waived. A total of 41 patients who underwent head CT before and shortly after death were enrolled. Hounsfield units (HUs) of gray matter (GM) and white matter (WM) were measured at the levels of the basal ganglia, centrum semiovale, and high convexity area on both antemortem and postmortem CT. The length of the minor axis of the third ventricle at the level of the basal ganglia and the width of the central sulcus at the level of high convexity were measured.

Results

At each level tested, the HUs of GM and the GM/WM ratios on postmortem CT were significantly lower than those on antemortem CT (P < 0.001). HUs of WM on postmortem CT were slightly higher than those on antemortem CT but without significant difference (P > 0.1). Postmortem CT showed subtle loss of distinction between GM and WM. The size of the third ventricle and the width of the central sulcus did not vary before and after death (P > 0.1).

Conclusion

Early postmortem CT shows mild brain edema but does not show brain swelling.     

Incidental occult gunshot wound detected by postmortem computed tomography

The body of a 59 year old woman underwent postmortem computed tomography (PMCT) examination prior to forensic autopsy, using a 256 slice multidetector row computed tomography scanner. A large left tension pneumothorax detected on the PMCT was considered to be a likely cause of death and this was confirmed at autopsy. In addition there was an unsuspected PMCT finding of a probable gunshot injury traversing the right orbit, facial bones and frontal sinus. The autopsy technique was adjusted accordingly and PMCT findings confirmed. PMCT in this case was not only diagnostic of cause of death, but also revealed retained projectile fragments of an old gunshot wound to the face. Without prior imaging such findings would have been undetected at autopsy. This case further underscores the contribution of routine PMCT examination to forensic autopsy practice.     

Association between postmortem computed tomography value of cerebrospinal fluid and time after death: A longitudinal study of antemortem and postmortem computed tomography

This study was designed to examine the antemortem factors affecting cerebrospinal fluid (CSF) Hounsfield Units (HU) on postmortem computed tomography (PMCT) compared to the antemortem CT (AMCT). Fifty-five participants without brain lesions who died at a university hospital and underwent AMCT, PMCT, and an autopsy were enrolled. We recorded age, sex, time after death, the CSF HU on AMCT and PMCT at multiple measuring points, 4-point-scale brain atrophy grade on AMCT, and the cella media index. We tested the effects of CSF HU factors observed on PMCT. No significant differences were observed between CSF HUs at any of the PMCT measurement points. The average CSF HU on PMCT was positively correlated with the natural logarithm of the time after death (Pearson's correlation coefficient, 0.81; p < 0.001). No other factors showed correlative relationships. Up until approximately 12 h after death, the CSF HU on PMCT depended only on the time since death.     

Pre-procedural multi-slice computed tomography (MSCT) in aortic valve replacement. Important measurements

PurposeTo describe the preoperative role of MSCT in aortic valve lesions regarding detection of valve morphological changes and important measurements needed for valve replacement.Subjects and methodsThis was a prospective study included 24 patients their mean age 53.4 years, with known aortic valve stenosis (AS) or regurgitation (AR) over a study period 1 year. All patients underwent CT angiography using 128 MSCT. The coronary angiography was done by means of a bolus tracking technique. Measurements were conventionally made from an “optimized” sagittal oblique left ventricular outflow tract (LVOT) reconstruction.ResultsThe most common cause for aortic valve lesion was degenerative (63%). Echocardiography (ECHO) and MSCT had highly statistically significant kappa agreement in differentiating AS and AR. The mean aortic valve area (AVA) in AS and AR were (1.2 ± 0.5 and 3.8 ± 0.3 cm²) with p value (0.000⁷). Aortic valve dimension at sinus of valsalva were (3.5 ± 0.2 & 4.6 ± 0.7 cm) in AS and AR respectively. At the sino-tubular junction (STJ) were (3.1 ± 0.2 & 4.4 ± 1.4) in AS and AR respectively. The mean aortic annulus area was (5.7 ± 1.3 cm²) in AS and (6.6 ± 0.8 cm²) in AR. MSCT was more significant than ECHO in detection and grading of calcification (p value < 0.01). The distance from the aortic annulus to the ostia of the left and the right coronary arteries were (1.8 ± 0.3 cm) and (1.6 ± 0.3 cm) respectively. Concomitant coronary atherosclerosis and >50% attenuated lumen was detected in (25% &12.5%) of our patients respectively.ConclusionThe familiarity with the MSCT features of aortic valve and using various measurements are considered to be helpful for the accurate diagnosis and proper pre-operative valve replacement preparation.     

Superior pericardial recess simulating aortic dissection on computed tomography

Computed tomography is frequently used in the initial workup of patients with suspected aortic dissection to distinguish dissection involving the ascending aorta from dissection limited to the descending aorta. We reviewed CT of 19 patients who were proven by aortography to have normal ascending aortas. In eight patients the superior extension of the pericardium was visualized and thought to be a potential source of a false-positive diagnosis of type A aortic dissection.     

Flat-detector computed tomography (FD-CT)

Flat-panel detectors or, synonymously, flat detectors (FDs) have been developed for use in radiography and fluoroscopy with the defined goal to replace standard X-ray film, film-screen combinations and image intensifiers by an advanced sensor system. FD technology in comparison to X-ray film and image intensifiers offers higher dynamic range, dose reduction, fast digital readout and the possibility for dynamic acquisitions of image series, yet keeping to a compact design. It appeared logical to employ FD designs also for computed tomography (CT) imaging. Respective efforts date back a few years only, but FD-CT has meanwhile become widely accepted for interventional and intra-operative imaging using C-arm systems. FD-CT provides a very efficient way of combining two-dimensional (2D) radiographic or fluoroscopic and 3D CT imaging. In addition, FD technology made its way into a number of dedicated CT scanner developments, such as scanners for the maxillo-facial region or for micro-CT applications. This review focuses on technical and performance issues of FD technology and its full range of applications for CT imaging. A comparison with standard clinical CT is of primary interest. It reveals that FD-CT provides higher spatial resolution, but encompasses a number of disadvantages, such as lower dose efficiency, smaller field of view and lower temporal resolution. FD-CT is not aimed at challenging standard clinical CT as regards to the typical diagnostic examinations; but it has already proven unique for a number of dedicated CT applications, offering distinct practical advantages, above all the availability of immediate CT imaging in the interventional suite or the operating room.     

Normal thoracic aortic diameters by computed tomography

Although computed tomography (CT) has played an important role in evaluation of the thoracic aorta, no standards for aortic dimensions exist. To establish the range of normal variation of aortic diameters, a retrospective study of 102 chest CT studies in adults without clinical evidence of hypertension, diabetes, cardiovascular disease, or renal disease was performed. The coronal aortic diameter was measured at three levels: just beneath the aortic arch, just above the aortic valve, and at the level of the diaphragm. These measurements showed substantial variation according to age, sex, and thoracic vertebral body width. The ratio between the ascending and descending limbs of the aorta varied markedly with age; younger individuals had significantly higher ratios than older age groups. Knowledge of these values allows more precise CT evaluation in suspected aortic disease, specifically reducing the potential for "overinterpretation" of the normal, but prominent, ascending aortic root.