Maximum intensity projection of cranial computed tomography data for dental identification

Dental radiographs play the major role in the identification of victims in mass casualties besides DNA. Under circumstances such as those caused by the recent tsunami in Asia, it is nearly impossible to document the entire dentition using conventional x-rays as it would be too time consuming. Multislice computed tomography can be used to scan the dentition of a deceased within minutes, and the postprocessing software allows visualization of the data adapted to every possible antemortem x-ray for identification. We introduce the maximum intensity projection of cranial computed tomography data for the purpose of dental identification exemplarily in a case of a burned corpse. As transportable CT scanners already exist, these could be used to support the disaster victim identification teams in the field.

Effects of dose reduction on the detectability of standardized radiolucent lesions in digital panoramic radiography

Dose reduction in digital panoramic radiography was studied. Intentional underexposure was performed with the Orthophos DS while six different human mandibles were radiographed. Exposure settings were 69 kV/15 mA (standard), 64 kV/16 mA, and 60 kV/16 mA. Standardized spherical defects, each either 1 or 1.25 mm in diameter, were simulated in 288 of 432 images, and seven observers decided whether defects were present or not. Areas under the receiver operating characteristics curves were calculated. They showed no significant differences in the detectability of the 1-mm defect at 69, 64, or 60 kV. For the 1.25-mm defect, no difference was found between the 69 and 60 kV images, but a statistically significant different detectability was found for 64 kV images in comparison with both 69 and 60 kV images. A dose reduction of up to 43% was ascertained with a Pedo-RT-Humanoid phantom when panoramic radiography was performed at 60 kV/16 mA. The conclusion is that with the Orthophos DS, it seems possible to reduce the dose rate of x-rays without loss of diagnostic quality in the case of radiolucent changes.

Radioprotection of cultured cells by preincubation in medium containing deuterium oxide

Pretreatment with deuterium oxide (D2O) has been shown to protect mice against lethal effects of X-rays. In contrast, X-irradiation of cultured mammalian cells in D2O-containing medium has previously been reported to result in increased cell killing. Therefore, the effects of preincubation in medium containing 20% D2O on radiosensitivity were tested, using cells of a heat-sensitive cell-cycle mutant (21-Tb) of the murine mastocytoma P 815-X2. The mutant cells proliferate at 33 degrees C and are arrested in G1 phase in a state of reversible proliferative quiescence at 39.5 degrees C. Prior to irradiation with single X-ray doses of 0-10 Gy, the cells were cultured in normal or D2O-containing medium, either for 96 h at 33 degrees C ('proliferating cells'), or for 72 h at 33 degrees C followed by 24 h at 39.5 degrees C ('arrested cells'). After X-irradiation the cells were resuspended in normal medium, and cell survival was determined by the capacity of cells to form colonies in fibrin gels. Preincubation in medium containing 20% D2O resulted in a radioprotective effect on both proliferating and arrested cells, particularly at the higher X-ray doses. This radioprotection was manifested as a decreased slope of the semilogarithmic survival curves, whereas pretreatment with D2O had no significant effect on postirradiation repair as judged from Dq values. These results support the interpretation that the increase in postirradiation survival may be attributed to incorporation of deuterium into cellular metabolites during the period of preincubation.

Pelvic radiography in ATLS algorithms: A diminishing role?

ABSTRACT: BACKGROUND: Pelvic x-ray is a routine part of the primary survey of polytraumatized patients according to Advanced Trauma Life Support (ATLS) guidelines. However, pelvic CT is the gold standard imaging technique in the diagnosis of pelvic fractures. This study was conducted to confirm the safety of a modified ATLS algorithm omitting pelvic x-ray in hemodynamically stable polytraumatized patients with clinically stable pelvis in favour of later pelvic examination by CT scan. METHODS: We conducted a retrospective analysis of all polytraumatized patients in our emergency room between 01.07.2004 and 31.01.2006. Inclusion criteria were blunt abdominal trauma, initial hemodynamic stability and a stable pelvis on clinical examination. We excluded patients requiring immediate intervention because of hemodynamic instability. RESULTS: We reviewed the records of n = 452 polytraumatized patients, of which n = 91 fulfilled inclusion criteria (56% male, mean age = 45 years). The mechanism of trauma included 43% road traffic accidents, 47% falls. In 68/91 (75%) patients, both a pelvic x-ray and a CT examination were performed; the remainder had only pelvic CT. In 6/68 (9%) patients, pelvic fracture was diagnosed by pelvic x-ray. None of these 6 patients was found having a false positive pelvic x-ray, i.e. there was no fracture on pelvic CT scan. In 3/68 (4%) cases a fracture was missed in the pelvic x-ray, but confirmed on CT (false negative on x-ray). None of the diagnosed fractures needed an immediate therapeutic intervention. 5 (56%) were classified type A fractures, and another 4 (44%) B 2.1 in computed tomography (AO classification). One A 2.1 fracture was found in a clinically stable patient who only received CT scan (1/23). CONCLUSION: While pelvic x-ray is an integral part of ATLS assessment, this retrospective study suggests that in hemodynamically stable patients with clinically stable pevis, its sensitivity is only 67% and it may safely be omitted in favor of a pelvic CT examination if such is planned in adjunct assessment and available. The results support the safety and utility of our modified ATLS algorithm. A randomized controlled trial using the algorithm can safely be conducted to confirm the results.

Unstable bicondylar tibial plateau fractures: a clinical investigation

OBJECTIVE: To evaluate fracture patterns in bicondylar tibial plateau fractures and their impact on treatment strategy. DESIGN: Prospective data analysis with documentation of initial injury and treatment strategy, computed tomography scans, conventional x-rays, long-term evaluation of radiographs, and functional assessments. SETTING: Level 1 regional trauma center. PATIENTS: Prospective data acquisition of 14 consecutive patients (10 male and 4 female) with a bicondylar tibial plateau fracture (AO Type C). INTERVENTION: Application of a stepwise reconstruction strategy of the tibial plateau starting with the reposition and fixation of the posteromedial split fragment using a 3.5 buttress plate, followed by reposition and grafting of the lateral compartment and lateral fixation with a 3.5 plate in 90 degree to the medial fixation device. MAIN OUTCOME MEASUREMENTS: All patients were evaluated with full-length standing film, standardized x-rays, Lysholm score for functional assessment, and patient's self-appraisal. RESULTS: Most of the complex bicondylar fractures follow a regular pattern in that the medial compartment is split in a mediolateral direction with a posteromedial main fragment, combined with various amounts of multifragmental lateral compartment depression. The technique introduced allows for accurate and stable reduction and fixation of this fracture type. The final Lysholm knee score showed an average of 83.5 points (range: 64.5-92). CONCLUSIONS: Complex bicondylar tibial plateau fractures follow a regular pattern, which is not represented in existing 2-dimensional fracture classifications. A 2-incision technique starting with the reduction of the posteromedial edge results in accurate fracture reduction with low complication rates and excellent knee function.

Comparison of interferon-gamma release assay versus tuberculin skin test for tuberculosis screening in inflammatory bowel disease

OBJECTIVES: Reactivation of latent tuberculosis (TB) in inflammatory bowel disease (IBD) patients treated with antitumor necrosis factor-alpha medication is a serious problem. Currently, TB screening includes chest x-rays and a tuberculin skin test (TST). The interferon-gamma release assay (IGRA) QuantiFERON-TB Gold In-Tube (QFT-G-IT) shows better specificity for diagnosing TB than the skin test. This study evaluates the two test methods among IBD patients. METHODS: Both TST and IGRA were performed on 212 subjects (114 Crohn's disease, 44 ulcerative colitis, 10 indeterminate colitis, 44 controls). RESULTS: Eighty-one percent of IBD patients were under immunosuppressive therapy; 71% of all subjects were vaccinated with Bacille Calmette Guérin; 18% of IBD patients and 43% of controls tested positive with the skin test (P < 0.0001). Vaccinated controls tested positive more often with the skin test (52%) than did vaccinated IBD patients (23%) (P = 0.011). Significantly fewer immunosuppressed patients tested positive with the skin test than did patients not receiving therapy (P = 0.007); 8% of patients tested positive with the QFT-G-IT test (14/168) compared to 9% (4/44) of controls. Test agreement was significantly higher in the controls (P = 0.044) compared to the IBD group. CONCLUSIONS: Agreement between the two test methods is poor in IBD patients. In contrast to the QFT-G-IT test, the TST is negatively influenced by immunosuppressive medication and vaccination status, and should thus be replaced by the IGRA for TB screening in immunosuppressed patients having IBD.

[Atypical case of bronchus carcinoma]

Bronchuscarcinoma ist the most frequent death cause with tumor patients. At time of diagnosis the stadium is often already advanced, the patient is inoperable. We present a patient (non-smoker) with polydipsia, visual troubles and polyuria. The lab results confirmed diabetes insipidus, but the following x-rays proved multiple intracerebral spots. And also multiple spots in the lungs, the mediastinum, in the liver, the coloumn and the adrenals. Histological diagnosis was non small cell lung cancer (NSCLC).

Reaction Control in Quiescent Systems of Free-Radical Retrograde-Precipitation Polymerization

Free-radical retrograde-precipitation polymerization, FRRPP in short, is a novel polymerization process discovered by Dr. Gerard Caneba in the late 1980s. The current study is aimed at gaining a better understanding of the reaction mechanism of the FRRPP and its thermodynamically-driven features that are predominant in controlling the chain reaction. A previously developed mathematical model to represent free radical polymerization kinetics was used to simulate a classic bulk polymerization system from the literature. Unlike other existing models, such a sparse-matrix-based representation allows one to explicitly accommodate the chain length dependent kinetic parameters. Extrapolating from the past results, mixing was experimentally shown to be exerting a significant influence on reaction control in FRRPP systems. Mixing alone drives the otherwise severely diffusion-controlled reaction propagation in phase-separated polymer domains. Therefore, in a quiescent system, in the absence of mixing, it is possible to retard the growth of phase-separated domains, thus producing isolated polymer nanoparticles (globules). Such a diffusion-controlled, self-limiting phenomenon of chain growth was also observed using time-resolved small angle x-ray scattering studies of reaction kinetics in quiescent systems of FRRPP. Combining the concept of self-limiting chain growth in quiescent FRRPP systems with spatioselective reaction initiation of lithography, microgel structures were synthesized in a single step, without the use of molds or additives. Hard x-rays from the bending magnet radiation of a synchrotron were used as an initiation source, instead of the more statistally-oriented chemical initiators. Such a spatially-defined reaction was shown to be self-limiting to the irradiated regions following a polymerization-induced self-assembly phenomenon. The pattern transfer aspects of this technique were, therefore, studied in the FRRP polymerization of N-isopropylacrylamide (NIPAm) and methacrylic acid (MAA), a thermoreversible and ionic hydrogel, respectively. Reaction temperature increases the contrast between the exposed and unexposed zones of the formed microgels, while the irradiation dose is directly proportional to the extent of phase separation. The response of Poly (NIPAm) microgels prepared from the technique described in this study was also characterized by small angle neutron scattering.

Fructose overconsumption causes dyslipidemia and ectopic lipid deposition in healthy subjects with and without a family history of type 2 diabetes

BACKGROUND: Both nutritional and genetic factors are involved in the pathogenesis of nonalcoholic fatty liver disease and insulin resistance. OBJECTIVE: The aim was to assess the effects of fructose, a potent stimulator of hepatic de novo lipogenesis, on intrahepatocellular lipids (IHCLs) and insulin sensitivity in healthy offspring of patients with type 2 diabetes (OffT2D)--a subgroup of individuals prone to metabolic disorders. DESIGN: Sixteen male OffT2D and 8 control subjects were studied in a crossover design after either a 7-d isocaloric diet or a hypercaloric high-fructose diet (3.5 g x kg FFM(-1) x d(-1), +35% energy intake). Hepatic and whole-body insulin sensitivity were assessed with a 2-step hyperinsulinemic euglycemic clamp (0.3 and 1.0 mU x kg(-1) x min(-1)), together with 6,6-[2H2]glucose. IHCLs and intramyocellular lipids (IMCLs) were measured by 1H-magnetic resonance spectroscopy. RESULTS: The OffT2D group had significantly (P < 0.05) higher IHCLs (+94%), total triacylglycerols (+35%), and lower whole-body insulin sensitivity (-27%) than did the control group. The high-fructose diet significantly increased IHCLs (control: +76%; OffT2D: +79%), IMCLs (control: +47%; OffT2D: +24%), VLDL-triacylglycerols (control: +51%; OffT2D: +110%), and fasting hepatic glucose output (control: +4%; OffT2D: +5%). Furthermore, the effects of fructose on VLDL-triacylglycerols were higher in the OffT2D group (group x diet interaction: P < 0.05). CONCLUSIONS: A 7-d high-fructose diet increased ectopic lipid deposition in liver and muscle and fasting VLDL-triacylglycerols and decreased hepatic insulin sensitivity. Fructose-induced alterations in VLDL-triacylglycerols appeared to be of greater magnitude in the OffT2D group, which suggests that these individuals may be more prone to developing dyslipidemia when challenged by high fructose intakes. This trial was registered at clinicaltrials.gov as NCT00523562.

Improvement of LaBr3:5%Ce scintillation properties by Li+, Na+, Mg2+, Ca2+, Sr2+, and Ba2+ co-doping

This paper reports on the effects of Li+, Na+, Mg2+, Ca2+, Sr2+, and Ba2+ co-doping on the scintillation properties of LaBr3:5%Ce3+. Pulse-height spectra of various gamma and X-ray sources with energies from 8 keV to 1.33 MeV were measured from which the values of light yield and energy resolution were derived. Sr2+ and Ca2+ co-doped crystals showed excellent energy resolution as compared to standard LaBr3:Ce. The proportionality of the scintillation response to gamma and X-rays of Ca2+, Sr2+, and Ba2+ co-doped samples also considerably improves. The effects of the co-dopants on emission spectra, decay time, and temperature stability of the light yield were studied. Multiple thermoluminescence glow peaks, decrease of the light yield at temperatures below 295 K, and additional long scintillation decay components were observed and related to charge carrier traps appearing in LaBr3:Ce3+ with Ca2+, Sr2+, and Ba2+ co-doping.

DXA predictions of human femoral mechanical properties depend on the load configuration

The aim of this study was to evaluate the ability of dual energy X-rays absorptiometry (DXA) areal bone mineral density (aBMD) measured in different regions of the proximal part of the human femur for predicting the mechanical properties of matched proximal femora tested in two different loading configurations. 36 pairs of fresh frozen femora were DXA scanned and tested until failure in two loading configurations: a fall on the side or a one-legged standing. The ability of the DXA output from four different regions of the proximal femur in predicting the femoral mechanical properties was measured and compared for the two loading scenarios. The femoral neck DXA BMD was best correlated to the femoral ultimate force for both configurations and predicted significantly better femoral failure load (R2=0.80 vs. R2=0.66, P<0.05) when simulating a side than when simulating a standing configuration. Conversely, the work to failure was predicted similarly for both loading configurations (R2=0.54 vs. R2=0.53, P>0.05). Therefore, neck BMD should be considered as one of the key factors for discriminating femoral fracture risk in vivo. Moreover, the better predictive ability of neck BMD for femoral strength if tested in a fall compared to a one-legged stance configuration suggests that DXA's clinical relevance may not be as high for spontaneous femoral fractures than for fractures associated to a fall.

AN IMPLANTABLE MOSFET DOSIMETER MODIFIED TO ACT AS A FIDUCIAL MARKER

In external beam radiation therapy, it is imperative that the prescribed dose is administered to the correct location and in the correct amount. Though several ex vivo methods of quality assurance are currently employed to achieve this goal, verifying that the correct dose is received within the patient in situ is impossible without the capability of measuring dose inside the patient. Recently, a method of measuring dose delivered within the patient has been developed, an implantable MOSFET dosimeter. This dosimeter is implanted within the patient and records the dose received. Since the dosimeter is implanted in the patient, it could serve a dual function as a fiducial marker for image guided radiation therapy (IGRT) treatment if it could be modified to be visible on x-rays. In this study, modifications to the MOSFET dosimeter were made to increase its visibility for IGRT treatment. To test whether the modifications hindered the dosimeter’s ability to accurately measure and transmit dose information, the energy dependence, angular dependence and wireless read range of the modified dosimeter were measured and compared to unmodified dosimeters. It was found that the modified dosimeter performed as well as the unmodified dosimeter while also being suitable for use as a fiducial marker for IGRT treatment.

LiLa-Klassifikation für Frakturen der langen Röhrenknochen im Wachstumsalter

Background. There are two child-specific fracture classification systems for long bone fractures: the AO classification of pediatric long-bone fractures (PCCF) and the LiLa classification of pediatric fractures of long bones (LiLa classification). Both are still not widely established in comparison to the adult AO classification for long bone fractures. Methods. During a period of 12 months all long bone fractures in children were documented and classified according to the LiLa classification by experts and non-experts. Intraobserver and interobserver reliability were calculated according to Cohen (kappa). Results. A total of 408 fractures were classified. The intraobserver reliability for location in the skeletal and bone segment showed an almost perfect agreement (K=0.91-0.95) and also the morphology (joint/shaft fracture) (K=0.87-0.93). Due to different judgment of the fracture displacement in the second classification round, the intraobserver reliability of the whole classification revealed moderate agreement (K=0.53-0.58). Interobserver reliability showed moderate agreement (K=0.55) often due to the low quality of the X-rays. Further differences occurred due to difficulties in assigning the precise transition from metaphysis to diaphysis. Conclusions. The LiLa classification is suitable and in most cases user-friendly for classifying long bone fractures in children. Reliability is higher than in established fracture specific classifications and comparable to the AO classification of pediatric long bone fractures. Some mistakes were due to a low quality of the X-rays and some due to difficulties to classify the fractures themselves. Improvements include a more precise definition of the metaphysis and the kind of displacement. Overall the LiLa classification should still be considered as an alternative for classifying pediatric long bone fractures.

Efficient estimation of the total number of acini in adult rat lung

Pulmonary airways are subdivided into conducting and gas-exchanging airways. An acinus is defined as the small tree of gas-exchanging airways, which is fed by the most distal purely conducting airway. Until now a dissector of five consecutive sections or airway casts were used to count acini. We developed a faster method to estimate the number of acini in young adult rats. Right middle lung lobes were critical point dried or paraffin embedded after heavy metal staining and imaged by X-ray micro-CT or synchrotron radiation-based X-rays tomographic microscopy. The entrances of the acini were counted in three-dimensional (3D) stacks of images by scrolling through them and using morphological criteria (airway wall thickness and appearance of alveoli). Segmentation stopper were placed at the acinar entrances for 3D visualizations of the conducting airways. We observed that acinar airways start at various generations and that one transitional bronchiole may serve more than one acinus. A mean of 5612 (±547) acini per lung and a mean airspace volume of 0.907 (±0.108) μL per acinus were estimated. In 60-day-old rats neither the number of acini nor the mean acinar volume did correlate with the body weight or the lung volume.