Neuroprotective mechanisms of erythropoietin in a rat stroke model.

OBJECTIVE: This study was designed to investigate the indirect neuroprotective properties of recombinant human erythropoietin (rhEPO) pretreatment in a rat model of transient middle cerebral artery occlusion (MCAO). METHODS: One hundred and ten male Wistar rats were randomly assigned to four groups receiving either 5,000 IU/kg rhEPO intravenously or saline 15 minutes prior to MCAO and bilateral craniectomy or sham craniectomy. Bilateral craniectomy aimed at elimination of the space-consuming effect of postischemic edema. Diagnostic workup included neurological examination, assessment of infarct size and cerebral edema by magnetic resonance imaging, wet-dry technique, and quantification of hemispheric and local cerebral blood flow (CBF) by flat-panel volumetric computed tomography. RESULTS: In the absence of craniectomy, EPO pretreatment led to a significant reduction in infarct volume (34.83 ± 9.84% vs. 25.28 ± 7.03%; p = 0.022) and midline shift (0.114 ± 0.023 cm vs. 0.083 ± 0.027 cm; p = 0.013). We observed a significant increase in regional CBF in cortical areas of the ischemic infarct (72.29 ± 24.00% vs. 105.53 ± 33.10%; p = 0.043) but not the whole hemispheres. Infarct size-independent parameters could not demonstrate a statistically significant reduction in cerebral edema with EPO treatment. CONCLUSIONS: Single-dose pretreatment with rhEPO 5,000 IU/kg significantly reduces ischemic lesion volume and increases local CBF in penumbral areas of ischemia 24 h after transient MCAO in rats. Data suggest indirect neuroprotection from edema and the resultant pressure-reducing and blood flow-increasing effects mediated by EPO.

Quantitative computed tomography applied to interstitial lung diseases.

OBJECTIVES: To evaluate a new image marker that retrieves information from computed tomography (CT) density histograms, with respect to classification properties between different lung parenchyma groups. Furthermore, to conduct a comparison of the new image marker with conventional markers. MATERIALS AND METHODS: Density histograms from 220 different subjects (normal = 71; emphysema = 73; fibrotic = 76) were used to compare the conventionally applied emphysema index (EI), 15th percentile value (PV), mean value (MV), variance (V), skewness (S), kurtosis (K), with a new histogram's functional shape (HFS) method. Multinomial logistic regression (MLR) analyses was performed to calculate predictions of different lung parenchyma group membership using the individual methods, as well as combinations thereof, as covariates. Overall correct assigned subjects (OCA), sensitivity (sens), specificity (spec), and Nagelkerke's pseudo R2 (NR2) effect size were estimated. NR2 was used to set up a ranking list of the different methods. RESULTS: MLR indicates the highest classification power (OCA of 92%; sens 0.95; spec 0.89; NR2 0.95) when all histogram analyses methods were applied together in the MLR. Highest classification power among individually applied methods was found using the HFS concept (OCA 86%; sens 0.93; spec 0.79; NR2 0.80). Conventional methods achieved lower classification potential on their own: EI (OCA 69%; sens 0.95; spec 0.26; NR2 0.52); PV (OCA 69%; sens 0.90; spec 0.37; NR2 0.57); MV (OCA 65%; sens 0.71; spec 0.58; NR2 0.61); V (OCA 66%; sens 0.72; spec 0.53; NR2 0.66); S (OCA 65%; sens 0.88; spec 0.26; NR2 0.55); and K (OCA 63%; sens 0.90; spec 0.16; NR2 0.48). CONCLUSION: The HFS method, which was so far applied to a CT bone density curve analysis, is also a remarkable information extraction tool for lung density histograms. Presumably, being a principle mathematical approach, the HFS method can extract valuable health related information also from histograms from complete different areas.

Comparison between flat-panel volume computed tomography and histologic assessments of bone invasion of maxillofacial tumors: utility of an instantaneous radiologic diagnostic tool.

OBJECTIVE: The aim of this study was to compare the accuracy of flat-panel volume computed tomography (fpVCT) to histopathologic evaluation of excised tumors of the jaws in the detection of the degree of tumor infiltration, the presence of tumor at the resection margins, and the sizes of lesions. STUDY DESIGN: This preliminary study included 47 patients undergoing jaw resection for tumor invasion of bone. The specimens were examined by histology and 3-dimensional fpVCT, and the parameters of bone infiltration, resection margins, and tumor size were determined. RESULTS: In 95.7% of cases, the fpVCT results of tumorous bone infiltration were in accordance with the histologic findings. An examination of the resection margins showed 100% concordance between the 2 methods, and all resection margins were found to be clear in both fpVCT and the histologic examination. Identical pathologic and nonpathologic results were seen with the use of both diagnostic methods. Radiologic estimates of tumor size were larger than histologic measurements in the case of small tumors but the true sizes of the larger lesions were underestimated. CONCLUSIONS: The intraoperative diagnostic gap can be closed by using fpVCT to investigate bone destruction, allowing one-step resections and reconstructions to become more reliable.

The completely fused medial clavicular epiphysis in high-frequency ultrasound scans as a diagnostic criterion for forensic age estimations in the living.

The assessment of ossification of the medial clavicular epiphysis plays a decisive role in the forensic age estimation of living subjects. Primarily for reasons of minimizing the radiation exposure currently associated with such evaluations, non-ionizing methods would be an advance.This study pursued the question whether full union of the medial clavicular epiphysis, visualized by high-frequency sonography, is a reliable criterion for age-threshold determinations. The ossification stage of the medial clavicular epiphysis of 215 female and 195 male volunteers, aged between 14 and 26 years, was evaluated in bilateral sonograms. Stage 4, defined as complete fusion by Schulz et al. (Int J Legal Med 122:163-167, 2008), was observed on at least one body side in 48 of 334 individuals younger than 21 years (14.4 %) and in 32 of 264 individuals younger than 18 years (12.1 %).With the high-frequency ultrasound used in this study, even the smallest convexities of the medial clavicular ending can be visualized. This may have led to overestimation of the ossification stage. It is not clear whether any observed roundings in the sonograms should actually be interpreted in terms of stages 3 and 4 as defined by Schulz. Also, due to the low penetration depth of high-frequency ultrasound waves, epiphyseal plate residues and ossification centers may have remained undetected. Reliable differentiation of the stages 1-4 with high-frequency sonography is thus difficult, and the results suggest that this method is not a radiation-free alternative to computed tomography, the current gold standard for determining age thresholds.

Factors influencing intracranial vessel densities on unenhanced computed tomography: differences between hemispheres.

The aim was to identify the factors influencing intracranial vessel density (VD). The Hounsfield units of the dense vessel and the contralateral side were measured in 34 patients with arterial clots, 20 with venous clots, and 196 without clots and correlated with skull thickness, density and dimensions, gender, age, red blood cell count (RBC), hemoglobin (HB), hematocrit (HT), creatinine, and sodium. Positive correlations were found between VD and HT, RBC, HB, creatinine, and occipital bone density. Density differences between the right and left intracranial vessels were more accurate (sensitivity/specificity/accuracy=0.91/0.93/0.93 and 0.75/0.87/0.85, respectively) for detecting clots than VD alone. HT, RBC, and HB are the main factors that correlate with VD.

Aging adult skull vaults by applying the concept of fractal geometry to high-resolution computed tomography images.

INTRODUCTION: Aging human remains is a critical issue in anthropology and forensic medicine, and the search for accurate, new age-estimation methods is ongoing. In our study, we, therefore, explored a new approach to investigate a possible correlation between age-at-death (aad) and geometric irregularities in the bone structure of human skull caps. We applied the concept of fractal geometry and fractal dimension D analysis to describe heterogeneity within the bone structure. METHODS: A high-resolution flat-panel computed tomography scanner (eXplore Locus Ultra) was used to obtain 229,500 images from 221 male and 120 female (total 341) European human skulls. Automated image analysis software was developed to evaluate the fractal dimension D, using the mass radius method. The frontal and the occipital portions of the skull caps of adult females and males were investigated separately. The age dependence of the fractal dimension D was studied by correlation analysis, and the prediction accuracy of age-at-death (aad) estimates for individual observations was calculated. RESULTS: D values for human skull caps scatter strongly as a function of age. We found sex-dependent correlation coefficients (CC) between D and age for adults (females CC=-0.67; males CC=-0.05). Prediction errors for aad estimates for individual observations were in the range of ±18 years at a 75% confidence interval. CONCLUSIONS: The detailed quantitative description of age-dependent irregularities in the bone microarchitecture of skull vaults through fractal dimension analysis does not, as we had hoped, enable a new aging method. Severe scattering of the data leads to an estimation error that is too great for this method to be of practical relevance in aad estimates. Thus, we disclosed an interesting sex difference.

Immunomodulation by fish-oil containing lipid emulsions in murine acute respiratory distress syndrome.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) is a major cause of mortality in intensive care units. Patients with ARDS often require parenteral nutrition with lipid emulsions as essential components. Besides being an energy supply, these lipid emulsions might display differential modulatory effects on lung integrity and inflammation. METHODS: In a pre-emptive strategy, we investigated the impact of three different intravenously infused lipid emulsions on lung morphology, leukocyte invasion, protein leakage and cytokines in a murine model of ARDS. Mice received an infusion of normal saline solution, a pure long-chain triglycerides (LCT) emulsion, a medium-chain triglycerides (MCT) containing mixed emulsion (LCT/MCT), or a fish oil (FO) containing mixed emulsion (LCT/MCT/FO) before lipopolysaccharide (LPS) challenge. RESULTS: Mice pre-infused with fish oil-containing lipid emulsion showed decreased leukocyte invasion, protein leakage, myeloperoxidase activity, and cytokine production in their alveolar space after LPS challenge compared to mice receiving LCT or LCT/MCT. In line with these findings, lung morphology assessed by histological staining after LPS-induced lung injury improved faster in the LCT/MCT/FO group. Concerning the above mentioned parameters, no significant difference was observed between mice infused with LCT or the combination of LCT and MCT. CONCLUSION: Fish oil-containing lipid emulsions might exert anti-inflammatory and pro-resolving effects in the murine model of acute lung injury. Partial replacement of n-6 fatty acids with n-3 fatty acids may thus be of benefit for critically ill patients at risk for ARDS which require parenteral nutrition.

A relevant experimental model for human bronchiolitis obliterans syndrome.

BACKGROUND: The long-term success of human lung transplantation is limited by the development of bronchiolitis obliterans syndrome. Acute rejection episodes and infections are important risk factors and seem to play major pathogenic roles. We established a relevant experimental model that mimics important aspects of human bronchiolitis obliterans syndrome. METHODS: The Fischer 344-to-Lewis rat strain combination was used for orthotopic left lung transplantation. Isogeneic transplantations were performed in the Lewis rat. Recipients were treated with ciclosporin for 10 days. Lipopolysaccharide or vehicle was instilled into the airways 28 days after transplantation. Grafts were monitored by computed tomography, and recipients were euthanized on Days 28-90. The messenger RNA expression of selected chemokines and their receptors was measured on Days 28, 29, 33, 40 after transplantation. Graft histopathology on Day 90 was compared with lungs from patients who underwent re-transplantation due to end-stage allograft dysfunction. RESULTS: Lung allografts treated with ciclosporin and vehicle only sporadically displayed tissue remodeling. In contrast, lipopolysaccharide treatment induced severe inflammation. In the long-term, severe vascular remodeling, lung fibrosis, and fibroproliferative remodeling of airways were found that closely resemble the histopathologic changes in grafts from human patients with bronchiolitis obliterans syndrome. Chronic damage was virtually absent from pulmonary isografts and native right lungs. Chemokine (C-C motif) ligand 5 and chemokine (C-X-C motif) ligand 9-11, and their receptors, were over-expressed in allografts. CONCLUSIONS: Our experimental model mirrors key aspects of human bronchiolitis obliterans syndrome. It will be useful to elucidate its pathogenesis and to develop therapeutic approaches improving the long-term outcome of human lung transplantation.

Contrast-agent enhancement in ex vivo flat-panel computed tomography of locally advanced laryngeal cancer.

CONCLUSION: Visualization of cartilage invasion in ex vivo laryngectomy specimens was improved by flat-panel volumetric computed tomography (fpvCT) after diffusion of contrast agents. A prospective study to assess the specificity and sensitivity of this new method is warranted. OBJECTIVES: Cartilage invasion is a criterion for staging laryngeal squamous cell carcinoma. Contrast-enhanced CT is routinely used for assessing cartilage invasion. However, the sensitivities and specificities given for this method in the literature vary, and there is a need for improvement of this staging method. The objective of our pilot study was to determine cartilage invasion with fpvCT after contrast agent diffusion. METHODS: Three patients underwent preoperative CT and total laryngectomy. The excised larynges were immediately scanned with an fpvCT scanner, without contrast enhancement. Additional fpvCT scans were performed after incubation of the larynges in one of three different contrast agents for 24 and 48 h. The results from presurgical conventional scans, fpvCT scans, and histological examination - as the gold standard - were compared. RESULTS: We demonstrated the feasibility of ex vivo contrast enhancement of laryngeal tissues by diffusion, with a subsequent increase in contrast enhancement and improved visualization of cartilage invasion in fpvCT scans. Histology confirmed the fpvCT results.

Flat-panel volumetric computed tomography in cerebral perfusion: evaluation of three rat stroke models.

Flat-panel volumetric computed tomography (fpVCT) is a non-invasive approach to three-dimensional small animal imaging. The capability of volumetric scanning and a high resolution in time and space enables whole organ perfusion studies. We aimed to assess feasibility and validity of fpVCT in cerebral perfusion measurement with impaired hemodynamics by evaluation of three well-established rat stroke models for temporary and permanent middle cerebral artery occlusion (MCAO). Male Wistar rats were randomly assigned to temporary (group I: suture model) and permanent (group II: suture model; III: macrosphere model) MCAO and to a control group. Perfusion scans with respect to cerebral blood flow (CBF) and volume (CBV) were performed 24h post intervention by fpVCT, using a Gantry rotation time of 1s and a total scanning time of 30s. Postmortem analysis included infarct-size calculation by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Infarct volumes did not differ significantly throughout intervention groups. After permanent MCAO, CBF significantly decreased in subcortical regions to 78.2% (group II, p=0.005) and 79.9% (group III, p=0.012) and in total hemisphere to 77.4% (group II, p=0.010) and 82.0% (group III, p=0.049). CBF was less impaired with temporary vessel occlusion. CBV measurement revealed no significant differences. Results demonstrate feasibility of cerebral perfusion quantification in rats with the fpVCT, which can be a useful tool for non-invasive dynamic imaging of cerebral perfusion in rodent stroke models. In addition to methodological advantages, CBF data confirm the macrosphere model as a useful alternative to the suture model for permanent experimental MCAO.

Reconstruction of critical-size mandibular defects in immunoincompetent rats with human adipose-derived stromal cells.

In patients with bony defects, autologous bone grafts are the "gold standard" for reconstruction. In children, autologous bone harvesting is limited but tissue engineering offers an alternative. Next to bone marrow, adipose tissue is a source of mesenchymal stromal cells, and adipose-derived stromal cells (ADSC) can differentiate into osteocytes. The aim of this study was to evaluate the efficacy of bioactive implants (ADSC in fibrin glue) for repair of critical-size mandibular defects in athymic rats. Human adult ADSC embedded in fibrin glue were implanted into a critical-size defect in the rat mandible and their efficacy was compared to those of protected bone healing (pbh), autologous bone graft, and an empty defect. The newly formed bone was quantified using high-resolution flat-panel volumetric CT (fpvCT) during different observation times. After eight weeks, the specimens were assessed histologically and by micro-computed tomography (µ-CT). The radiographic examination demonstrated a significantly higher level of ossified defect area in the ADSC side compared with the pbh side. The autologous bone graft side showed significantly enhanced bone formation compared to the empty defect. The histological findings in the specimens with ADSC showed bony bridging of the defect. ADSC were capable of defect reconstruction under our experimental conditions.

Aging adult skull remains through radiological density estimates: A comparison of different computed tomography systems and the use of computer simulations to judge the accuracy of results.

INTRODUCTION: The objective of this article was to explore age-at-death estimates in forensic medicine, which were methodically based on age-dependent, radiologically defined bone-density (HC) decay and which were investigated with a standard clinical computed tomography (CT) system. Such density decay was formerly discovered with a high-resolution flat-panel CT in the skulls of adult females. The development of a standard CT methodology for age estimations--with thousands of installations--would have the advantage of being applicable everywhere, whereas only few flat-panel prototype CT systems are in use worldwide. METHODS: A Multi-Slice CT scanner (MSCT) was used to obtain 22,773 images from 173 European human skulls (89 male, 84 female), taken from a population of patients from the Department of Neuroradiology at the University Hospital Giessen and Marburg during 2010 and 2011. An automated image analysis was carried out to evaluate HC of all images. The age dependence of HC was studied by correlation analysis. The prediction accuracy of age-at-death estimates was calculated. Computer simulations were carried out to explore the influence of noise on the accuracy of age predictions. RESULTS: Human skull HC values strongly scatter as a function of age for both sexes. Adult male skull bone-density remains constant during lifetime. Adult female HC decays during lifetime, as indicated by a correlation coefficient (CC) of -0.53. Prediction errors for age-at-death estimates for both of the used scanners are in the range of ±18 years at a 75% confidence interval (CI). Computer simulations indicate that this is the best that can be expected for such noisy data. CONCLUSIONS: Our results indicate that HC-decay is indeed present in adult females and that it can be demonstrated both by standard and by high-resolution CT methods, applied to different subject groups of an identical population. The weak correlation between HC and age found by both CT methods only enables a method to estimate age-at-death with limited practical relevance since the errors of the estimates are large. Computer simulations clearly indicate that data with less noise and CCs in the order of -0.97 or less would be necessary to enable age-at-death estimates with an accuracy of ±5 years at a 75% CI.

Comparative dental radiographic identification using flat panel CT.

A skull without lower jaw was found and brought in for identification. It was suspected to be that of a man reported missing five years ago. An undated antemortal dental chart and two dental films of the 1st and 2nd dental quadrants, both taken about 4 years before the man went missing, were available for comparison. The method of choice in solving the identity question was comparative dental radiography. Despite numerous attempts, it was not possible to obtain radiographs of the upper jaw that duplicated the X-ray beam angulation of the antemortem dental films. The skull was thus scanned with a multislice computed tomography (MSCT) scanner, and virtual radiographs with the desired angulation were generated from the data with the maximum intensity projection (MIP) technique. The resulting virtual radiographs could, however, not be used for superimposition with the antemortem radiographs because of their poor resolution and the occurrence of artifacts caused by metallic dental fillings. The upper jaw was therefore scanned again, this time with a high resolution eLU-CT (eXplore Locus Ultra flat panel CT). The resulting eLU-CT datasets were visualized with the MIP technique and yielded virtual radiographs that could be compared with the antemortem radiographs. Positive identification could be assumed with near certainty after dental features could be matched in the superimposition of antemortem and postmortem radiographs. In the presented case, eLU-CT was used for the first time for a comparative dental radiographic identification.

Age and gender-dependent bone density changes of the human skull disclosed by high-resolution flat-panel computed tomography.

INTRODUCTION: The objective of this article was to estimate the age at death in forensic or anthropologic applications based on human skull investigation. Sex-dependent differences were analyzed. METHODS: Digital, high-resolution, flat-panel-based volumetric computed tomography (eXplore Locus Ultra scanner) images (165,920) of 244 European human skulls-163 males, 81 females-were analyzed according to their radiological bone density, based on Hounsfield units (H) that are directly related to the x-ray attenuation of the scanned material. Data were collected by the Department of Forensic Medicine at the University Hospital Giessen and Marburg during 2007 and 2008. Correlation analysis was used for data description. RESULTS: Human skull density estimates are widely scattered as a function of age for both sexes. Male skull bone density remains constant during lifetime, whereas female skull bone density decays slowly from approximately 20 years onwards. CONCLUSIONS: Bone density decay only theoretically provides a new method to determine age at death for adult females. Due to the scattering of the data, an accuracy of approximately ±18 years is found at a confidence interval of 75%, which is, unfortunately, of limited practical interest. We found new sex differences of bone density decay in the skull that are potentially of relevance for the general understanding of bone degradation processes.

[A study to narrow down the time when a hyoid bone fracture was sustained]. / Untersuchungen zur Eingrenzung der Entstehungszeit von Zungenbeinbrüchen.

An unstable hyoid bone that can be loosely moved during autopsy is initial reason to suspect trauma to the neck. The question to be answered is whether the increased mobility is due to incomplete ossification of the hyoid, a postmortem injury (damage), or an ante-mortem injury, possibly related to the cause of death. This is the first study to systematically assess whether stereomicroscopic examinations and flat-panel CT-scans of isolated, unstable hyoid bones can add information to the macroscopic examination by helping to determine when the instability arose. Sixteen isolated hyoid bones (8 female, 8 male; 4-87 years-old) were examined after being macerated. Four of the hyoid bones were already classified as unstable during autopsy. Of the other 12, 7 were fractured immediately after autopsy before being macerated, and 5 were fractured after being macerated. There were, in total, six different diagnostic constellations. Stereo-microscopic examination did not yield additional information compared with the macroscopic examination. Flat-panel CT allowed distinction between an incomplete ossification of the hyoid and a fracture, but did not help in determining whether the fracture had been sustained peri- or postmortem.

High-resolution flat-panel volumetric CT images show no correlation between human age and sagittal suture obliteration--independent of sex.

This study investigated whether digital, high-resolution CT-images of the internal human sagittal suture structure include information that enables a novel method of age at death (aad) determination. To accomplish this, coronal, flat-panel-based volumetric computed tomography (eXplore Locus Ultra scanner) images were automatically analyzed by a software implementation of an algorithm that determines user independent whether a suture is open or closed. 29,205 images of the local vicinity of the sagittal suture of 164 males and 85 females of European descent were investigated separately for both sexes. We used conditional probabilities and a chi(2)-test to investigate whether there is a correlation between aad and suture obliteration or not. The computer-aided analysis enables us to handle huge volumes of data that could not otherwise be analyzed within a reasonable time frame. The implemented algorithm ensured a strongly reproducible, reliable, accurate, and fast differentiation between closed and open sutures. The evaluation of various statistical parameters suggests that there is no reason to assume a correlation between age and suture closure--with equal findings for both sexes. Therefore, we conclude that determination of aad based on the evaluation of sagittal suture obliteration is not possible. This agrees well - thus unsatisfactorily - with the recent literature.

Ossification degrees of cranial sutures determined with flat-panel computed tomography: narrowing the age estimate with extrema.

Since Broca's time (1824-1880), ossification of the neurocranial sutures has been used as a characteristic of age. Current approaches include the visual macroscopic examination of ecto and endocranial sutures. The evaluation of the cross-section of sutures usually necessitates the destruction of the neurocranium. In a nondestructive alternative approach that was tested within the context of the "Digital Forensic Osteology" project that ran in cooperation with the Virtopsy-Project, it emerged that the resolution of conventional multi-slice computed tomography data sets was not high enough to image sutures. Thus for the experiments presented here, the eXplore Locus Ultra flat-panel computed tomography scanner from GE Healthcare was used. Calottes were scanned during autopsy and then immediately returned to the corpse. So far, the skullcaps of 221 individuals have been scanned. The cross-sections of 14 suture segments could be assessed for seven previously defined stages of ossification. In a converse step, the 14 highest and lowest age estimate values corresponding to the individual stages of suture closure found were estimated for each calotte. The obtained ranges narrowing down the age estimate were evaluated with statistics. A mean value of 43.31 years for the range of narrowed age estimates shows that this method can be a useful aid in estimating age. The results of intra- and inter-observer tests showed good overall agreement between the findings of three observers. This method is suitable for a nondestructive age estimation and can be used for the entire calotte.

Estimating age by assessing the ossification degree of cranial sutures with the aid of Flat-Panel-CT.

Estimating age from the skeletons of adults is difficult. The accuracy decreases for old age. Ossification of the neurocranial sutures has been used as an age characteristic since Broca's time (1824-1880). Although the sutures traverse the bone, current approaches only encompass the ecto- and endocranial sutures. Evaluating the cross-section of sutures necessitates the destruction of the neurocranium. In the context of the "Digital Forensic Osteology" project that ran in cooperation with the Virtopsy-Project it emerged that the resolution of conventional MSCT-data sets was not high enough to image sutures. The eXplore Locus Ultra (eLU) Flat-Panel-CT-Scanner from GE was used for these experiments. During autopsy, the skullcap was scanned and then immediately returned to the corpse. To date, the skullcaps of 221 individuals have been scanned. The data sets were reconstructed in 3D. The cross sections of the sutures of 14 segments could be evaluated in the cross-sectional view. Seven stages of ossification were defined and each segment was assessed for these. Several regression formulae for age estimation were developed from the results. This examination method is a suitable means for non-invasively evaluating the ossification degree of cranial sutures in the entire cross-section and for the entire calvarium. An increase in the number of examined individuals in this ongoing project and a look at extreme values will further heighten the conclusiveness of the results.

Monitoring of experimental rat lung transplants by high-resolution flat-panel volumetric computer tomography (fpVCT).

OBJECTIVE: Noninvasive assessment of experimental lung transplants with high resolution would be favorable to exclude technical failure and to follow up graft outcome in the living animal. Here we describe a flat-panel Volumetric Computed Tomography (fpVCT) technique using a prototype scanner. METHODS: Lung transplantation was performed in allogeneic as well as in corresponding syngeneic rat strain combinations. At different time points post-transplantation, fpVCT was performed. RESULTS: Lung transplants can be visualized in the living rat with high-spatial resolution. FpVCT allows a detailed analysis of the lung and the bronchi. Infiltrates developing during rejection episodes can be diagnosed and follow-up studies can easily be performed. CONCLUSIONS: With fpVCT it is possible to control the technical success of the surgical procedure. Graft rejection can be visualized individually in the living animal noninvasively, which is highly advantageous for studying the pathogenesis of chronic rejection or to monitor new therapies.