Towards computer aided diagnosis of infective endocarditis in whole-slide images of heart valve tissue using FISH

Infective endocarditis (IE) is an infection of the endocardium, and the heart valves associated with high morbidity and mortality. Fluorescence in situ Hybridization (FISH) is a molecular imaging technique used for diagnosis of IE based on histological heart valve tissue sections. FISH allows detection and identification of microorganisms and gives information about their quantity and spatial distribution. This information is important to guide appropriate antibiotic treatment. However, as manual FISH image analysis is time- and costexpensive, an automated image analysis pipeline (consisting of tissue segmentation, bacteria detection, and spot detection modules) is proposed to assist locating potential regions with microorganisms. The proposed approach was evaluated in a study, where five observers manually assessed a set of 171 fields-of-view (FoVs) captured in 400-fold magnification from 10 randomly chosen WSI for the presence of microorganisms, morphologically detected by the nucleic acid stain DAPI. The task of the observers was to mark the presented image using a 2-class score (‘positive/questionable’ or ‘negative’). The human assessment was compared to the results suggested by the algorithm. The proposed algorithm locates and ranks potential regions with microorganisms in heart valve sections so that experts can validate them in higher power FoVs for the presence of bacteria and identify their species. The automated system for preselecting and recommending adequate FoVs is thus a starting point to support experts and save human resources. It is now ready to be further developed for the detection of bacteria by FISH.

[The MDK Reform Act and its effect on outpatient potential : Risk or opportunity for urology?]

BACKGROUND

With the introduction of the MDK (Medizinischer Dienst der Krankenversicherung) Reform Act, there have been multiple new regulations for hospitals, some of which are confusing and interact with one another. A major focus of the legal changes is directly or indirectly on expanding the provision of outpatient services.

OBJECTIVES

It can be assumed that-as a result of the new version of the framework conditions and the AOP catalog-the relevant OPS list will be expanded in the future. With the revision of the AOP catalog and the effects of the MDK Reform Act, the number of cases with outpatient potential will increase. Can the effects and challenges for hospitals and especially urology be identified?

METHODS

Evaluation of official statistics of inpatient and outpatient treatments. Focusing on the problem based on a fictitious practical example from urology.

RESULTS

A strategy is developed for dealing with cases with outpatient potential and identification of different solutions to compensate for this shift in services and enabling an increase in performance or a deliberate reduction in the provision of services.

CONCLUSIONS

The choice of the type of service provision is increasingly no longer an issue, and the short-term inpatient treatment of many urological cases is coming under considerable pressure due to political measures such as the MDK Reform Act and the demands of health insurance companies. The reduction of different parts of the inpatient reimbursement for special patient groups must be anticipated. Individual strategies will range from simply not providing outpatient services to complex models of cooperation. This change also means opportunities for hospitals!

Use of antibiotic coated intramedullary nails in open tibia fractures: A European medical resource use and cost-effectiveness analysis

PURPOSE

In patients with open tibial fractures, bone and wound infections are associated with an increased hospital length of stay and higher costs. The infection risk increases with the use of implants. Innovations to reduce this risk include antibiotic-coated implants. This study models whether the use of a gentamicin-coated intramedullary tibial nail is cost-effective for trauma centers managing patients with a high risk of infection.

EFFICACY

Absolute infection risk and relative risk reduction, by fracture grade, for antibiotic-coated nails compared to standard nails for patients with open tibial fractures were estimated based on the results of a meta-analysis, which assessed the additional benefit of locally-administered prophylactic antibiotics in open tibia fractures treated with implants. The observed efficacy of antibiotic-coated nails in reducing infections was applied in an economic model.

METHODS

The model compared infection rates, inpatient days, theatre usage and costs in high risk patients, with a Gustilo-Anderson (GA) grade III open fracture, for two patient cohorts from a trauma center perspective, with a 1-year time horizon. In one cohort all GAIII patients received a gentamicin-coated nail whilst GAI and GAII patients received a standard nail. All patients in the comparator cohort received a standard nail. Four European trauma centers provided patient-level data (n=193) on inpatient days, procedures and related costs for patients with and without infections.

RESULTS

Using the gentamicin-coated nail in patients at high risk of infection (GAIII) was associated with 75% lower rate of infection and cost savings (€477 - €3.263) for all included centers; the higher cost of the implant was offset by savings from fewer infections, inpatient days (-26%) and re-operations (-10%). This result was confirmed by extensive sensitivity analyses.

CONCLUSIONS

Analyses demonstrated that infection rates and total costs for in-hospital treatment could be potentially reduced by 75% and up to 15% respectively, by using a gentamicin-coated nail in patients at high risk of infection. Fewer infections, reduced inpatient days and re-operations may be potentially associated with use of antibiotic-coated implants. Results are sensitive to the underlying infection risk, with greatest efficacy and cost-savings when the coated implant is used in high risk patients.

Regional variation in paraspinal muscle composition using chemical shift encoding-based water-fat MRI

Background

Paraspinal musculature forms one of the largest muscle compartments of the human body, but evidence for regional variation of its composition and dependency on gender or body mass index (BMI) is scarce.

Methods

This study applied six-echo chemical shift encoding-based water-fat magnetic resonance imaging (MRI) at 3 Tesla in 76 subjects (24 males and 52 females, age: 40.0±13.7 years, BMI: 25.4±5.6 kg/m²) to evaluate the proton density fat fraction (PDFF) of psoas muscles and erector spinae muscles, with the latter being divided into three segments in relation to levels of spine anatomy (L3-L5, T12-L2, and T9-T11).

Results

For the psoas muscles and the erector spinae muscles (L3-L5), gender differences in PDFF values were observed (PDFF psoas muscles: males: 5.1%±3.4% vs. females: 6.0%±2.2%, P=0.006; PDFF erector spinae muscles L3-L5: males: 10.7%±7.6% vs. females: 18.2%±6.8%, P<0.001). Furthermore, the PDFF of the erector spinae muscles (L3-L5) showed higher PDFF values when compared to the other segments (PDFF erector spinae muscles L3-L5 vs. T12-L2: P<0.001; PDFF erector spinae muscles L3-L5 vs. T9-T11: P<0.001) and showed to be independent of BMI, which was not the case for the other segments (T12-L2 or T9-T11) or the psoas muscles. When considering age and BMI as control variables, correlations of PDFF between segments of the erector spinae muscles remained significant for both genders.

Conclusions

This study explored regional variation of paraspinal muscle composition and dependency on gender and BMI, thus offering new insights into muscle physiology. The PDFF of the erector spinae muscles (L3-L5) was independent of BMI, suggesting that this level may be suited for representative paraspinal muscle segmentation and PDFF extraction as a biomarker for muscle alterations in the future.

Age- and gender-related variations of cervical muscle composition using chemical shift encoding-based water-fat MRI

PURPOSE

To understand fat distribution patterns and ectopic fat deposition in healthy adults and to provide normative data, encompassing the borders of physiological regional muscle composition. For this purpose chemical shift encoding-based water-fat Magnetic Resonance Imaging (MRI) was used for proton density fat fraction (PDFF) calculations.

MATERIAL AND METHODS

91 volunteers were enrolled (male: n = 28, age = 36.6 ± 11.4 years; female: n = 63, age = 38.5 ± 15.1 years). PDFF values combined for the multifidus, semispinalis and spinalis cervicis muscles at the level of the 3rd cervical vertebral body (C3), the 5th cervical vertebral body (C5) and the first thoracic vertebral body (Th1) were extracted.

RESULTS

The paraspinal musculature at C3 (14.8 ± 10.1 % vs. 19.2 ± 11.0 %; p = 0.029) and Th1 (13.8 ± 7.0 % vs 17.7 ± 7.4 %; p = 0.011) showed significantly lower PDFF values in men compared to women. Partial correlation testing with BMI as control variable revealed highly significant correlations between the paraspinal musculature PDFF at C3 (men: r = 0.504, p = 0.007; women: r = 0.279, p = 0.028), C5 (men: r = 0.450, p = 0.019; women: r = 0.347, p = 0.006) and Th1 (men: r = 0.652, p < 0.0001; women: r = 0.443, p < 0.0001) with age in both genders.

CONCLUSION

The present data suggest gender and age-specific fat deposition patterns of the cervical and the upper cervicothoracic paraspinal muscles and may provide reference values for pathology detection.

Association of thigh and paraspinal muscle composition in young adults using chemical shift encoding-based water-fat MRI

Background

Paraspinal and thigh muscles comprise the major muscle groups of the body. We investigated the composition of the psoas, erector spinae, quadriceps femoris and hamstring muscle groups and their association to each other using chemical shift encoding-based water-fat magnetic resonance imaging (MRI) in adult volunteers. Our aim was to elucidate fat distribution patterns within these muscle groups.

Methods

Thirty volunteers [15 males, age: 30.5±4.9 years, body mass index (BMI): 27.6±2.8 kg/m² and 15 females, age: 29.9±7.0 years, BMI: 25.8±1.4 kg/m²] were recruited for this study. A six-echo 3D spoiled gradient echo sequence was used for chemical shift encoding-based water-fat separation at the lumbar spine and bilateral thigh. Proton density fat fraction (PDFF), cross-sectional area (CSA) and contractile mass index (CMI) of the psoas, erector spinae, quadriceps femoris and hamstring muscle groups were determined bilaterally and averaged over both sides.

Results

CSA and CMI values calculated for the erector spinae, psoas, quadriceps and hamstring muscle groups showed significant differences between men and women (P<0.05). With regard to PDFF measurement only the erector spinae showed significant differences between men and women (9.5%±2.4% vs. 11.7%±2.8%, P=0.015). The CMI of the psoas muscle as well as the erector spinae muscle showed significant correlations with the quadriceps muscle (r=0.691, P<0.0001 and r=0.761, P<0.0001) and the hamstring group (r=0.588, P=0.001 and r=0.603, P<0.0001).

Conclusions

CMI values of the erector spinae and psoas muscles were associated with those of the quadriceps femoris and hamstring musculature. These findings suggest a concordant spatial fat accumulation within the analyzed muscles in young adults and warrants further investigations in ageing and diseased muscle.

Acceleration of chemical shift encoding-based water fat MRI for liver proton density fat fraction and T2* mapping using compressed sensing

Objectives

To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation.

Methods

Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used acceleration based on SENSE with a total acceleration factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used acceleration based on a combination of CS with SENSE with a total acceleration factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment.

Results

Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%).

Conclusion

CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.

Interactive Image Segmentation for Cochlea Implant Planning based on DVT Data

Cochlea Implant (CI) planning is usually based on preoperative obtained CT or MRI data, visualising risk structures in the petrosal bone. In the past years, Digital Volume Tomography (DVT) with an increased spatial resolution and reduced radiation has become more important in the clinical routine for otology. In this work we propose an extension of our interactive “wizard”-guided approach for the interactive segmentation of the middle and inner ear structures for the use with DVT data. Different filter pipelines enable the user to interactive segment the acoustic canal, ossicles, tympanic cavity, facial nerve, chorda tympani, round window, cochlea and semicircular canals. The approach has been evaluated on six pre-operative acquired DVT datasets by an ENT expert. Results imply that the proposed method can handle DVT well and can potentially be used for interactive OR planning.

[The cost estimator in the TraumaRegister DGU]

BACKGROUND AND OBJECTIVES

Estimated treatment costs of severely injured patients were often added to registry-based analyses. In the past, the TraumaRegister DGU® used a modular cost estimator for this purpose. A recent research project initiated by the German Trauma Society (DGU) evaluated the reimbursement of severely injured patients in the German DRG system. This project also allowed the generation of an improved update of the registry's cost estimator.

METHODS

Detailed cost data for the acute therapy of severely injured patients were available from 10 hospitals that also participate in the TraumaRegister DGU®. Cost and registry data were matched using hospital code, date of admission, age, sex, and length of stay. A multivariate regression analysis with hospital costs as dependent variable included patients with an injury severity score (ISS) ≥ 9 points who stayed in hospital at least three days. All injuries were coded using the abbreviated injury scale (AIS). A total of 1002 patients treated in 2007 and 2008 were successfully matched. Cost data was collected for each case according to the method of calculation provided by the German DRG Institute (InEK).

RESULTS

The mean age was 44 years and 73 % were males; the mean ISS was 27 points. The following aspects were significantly associated with the overall hospital costs: length of stay on the intensive care unit (ICU) (1152 € per day); length on intubation/ventilation (568 € per day); length of stay on normal ward (531 € per day); number of blood products (packed red blood cells; fresh frozen plasma) transfused until ICU admission (258 € per unit); a serious abdominal injury (AIS ≥3; 2849 €); an instable pelvic fracture with relevant blood loss (AIS 5; 7505 €); and a serious injury of the extremities (AIS 3-4; 2418 €). The estimated overall treatment costs calculated by the above mentioned formula averaged 22,138 € per case. The deviation from the measured real costs (21,546 € per case) was less than 3 %.

CONCLUSION

Using only key data available for all patients in the registry, a valid cost estimator for acute care costs is now available in the TraumaRegister DGU®.

Differentiating supraclavicular from gluteal adipose tissue based on simultaneous PDFF and T2 * mapping using a 20-echo gradient-echo acquisition

Background

Adipose tissue (AT) can be classified into white and brown/beige subtypes. Chemical shift encoding‐based water–fat MRI‐techniques allowing simultaneous mapping of proton density fat fraction (PDFF) and T₂* result in a lower PDFF and a shorter T₂* in brown compared with white AT. However, AT T₂* values vary widely in the literature and are primarily based on 6‐echo data. Increasing the number of echoes in a multiecho gradient‐echo acquisition is expected to increase the precision of AT T₂* mapping.

Purpose

1) To mitigate issues of current T₂*‐measurement techniques through experimental design, and 2) to investigate gluteal and supraclavicular AT T₂* and PDFF and their relationship using a 20‐echo gradient‐echo acquisition.

Study Type

Prospective.

Subjects

Twenty‐one healthy subjects.

Field Strength/Sequence Assessment

First, a ground truth signal evolution was simulated from a single‐T₂* water–fat model. Second, a time‐interleaved 20‐echo gradient‐echo sequence with monopolar gradients of neck and abdomen/pelvis at 3 T was performed in vivo to determine supraclavicular and gluteal PDFF and T₂*. Complex‐based water–fat separation was performed for the first 6 echoes and the full 20 echoes. AT depots were segmented.

Statistical Tests

Mann‐Whitney test, Wilcoxon signed‐rank test and simple linear regression analysis.

Results

Both PDFF and T₂* differed significantly between supraclavicular and gluteal AT with 6 and 20 echoes (PDFF: P < 0.0001 each, T₂*: P = 0.03 / P < 0.0001 for 6/20 echoes). 6‐echo T₂* demonstrated higher standard deviations and broader ranges than 20‐echo T₂*. Regression analyses revealed a strong relationship between PDFF and T₂* values per AT compartment (R² = 0.63 supraclavicular, R² = 0.86 gluteal, P < 0.0001 each).

Data Conclusion

The present findings suggest that an increase in the number of sampled echoes beyond 6 does not affect AT PDFF quantification, whereas AT T₂* is considerably affected. Thus, a 20‐echo gradient‐echo acquisition enables a multiparametric analysis of both AT PDFF and T₂* and may therefore improve MR‐based differentiation between white and brown fat.

Level of Evidence: 2

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2019;50:424–434.

Measuring large lipid droplet sizes by probing restricted lipid diffusion effects with diffusion-weighted MRS at 3T

Purpose

The in vivo probing of restricted diffusion effects in large lipid droplets on a clinical MR scanner remains a major challenge due to the need for high b‐values and long diffusion times. This work proposes a methodology to probe mean lipid droplet sizes using diffusion‐weighted MRS (DW‐MRS) at 3T.

Methods

An analytical expression for restricted diffusion was used. Simulations were performed to evaluate the noise performance and the influence of particle size distribution. To validate the method, oil‐in‐water emulsions were prepared and examined using DW‐MRS, laser deflection and light microscopy. The tibia bone marrow was scanned in volunteers to test the method repeatability and characterize microstructural differences at different locations.

Results

The simulations showed accurate and precise droplet size estimation when a sufficient SNR is reached with minor dependence on the size distribution. In phantoms, a good correlation between the measured droplet sizes by DW‐MRS and by laser deflection (R² = 0.98; P = 0.01) and microscopy (R² = 0.99; P < 0.01) measurements was obtained. A mean coefficient of variation of 11.5 % was found for the lipid droplet diameter in vivo. The average diameter was smaller at a proximal (50.1 ± 7.3 µm) compared with a distal tibia location (61.1 ± 6.8 µm) (P < 0.01).

Conclusion

The presented methods were able to probe restricted diffusion effects in lipid droplets using DW‐MRS and to estimate lipid droplet size. The methodology was validated using phantoms and the in vivo feasibility in bone marrow was shown based on a good repeatability and findings in agreement with literature.

Techniques and Applications of Magnetic Resonance Imaging for Studying Brown Adipose Tissue Morphometry and Function

The present review reports on the current knowledge and recent findings in magnetic resonance imaging (MRI) and spectroscopy (MRS) of brown adipose tissue (BAT). The work summarizes the features and mechanisms that allow MRI to differentiate BAT from white adipose tissue (WAT) by making use of their distinct morphological appearance and the functional characteristics of BAT. MR is a versatile imaging modality with multiple contrast mechanisms as potential candidates in the study of BAT, targeting properties of ¹H, ¹³C, or ¹²⁹Xe nuclei. Techniques for assessing BAT morphometry based on fat fraction and markers of BAT microstructure, including intermolecular quantum coherence and diffusion imaging, are first described. Techniques for assessing BAT function based on the measurement of BAT metabolic activity, perfusion, oxygenation, and temperature are then presented. The application of the above methods in studies of BAT in animals and humans is described, and future directions in MR study of BAT are finally discussed.

Gender- and Age-Related Changes in Trunk Muscle Composition Using Chemical Shift Encoding-Based Water⁻Fat MRI

Ageing, sarcopenia, and malnutrition are associated with quantitative and qualitative changes of body composition. There are several imaging modalities, including magnetic resonance imaging (MRI), for the assessment of trunk muscle tissue composition. In this study, we investigated the gender- and age-related changes in trunk muscle composition using chemical shift encoding-based water–fat MRI. A total of 79 healthy volunteers (26 men: 38.9 ± 10.4 years; 53 women: 39.5 ± 15.0 years) underwent 3T axial MRI using a six-echo multi-echo 3D spoiled gradient echo sequence, allowing for the calculation of the proton density fat fraction (PDFF) in the trunk muscles. PDFF of the abdominal, psoas, and erector spinae muscles were determined. We detected significant positive correlations for abdominal muscle PDFF with age (r = 0.638, p = 0.0001) in men, and for abdominal muscle PDFF (r = 0.709, p = 0.0001) and erector spinae muscle PDFF (r = 0.674, p = 0.0001) with age in women. After adjustment for body mass index (BMI), only the correlation of age and abdominal muscle PDFF in women remained significant (r = 0.631, p = 0.0001). The findings of this study suggest that an increasing fat deposition in muscle is driven primarily by age, rather than BMI, in women. These results further support that PDFF can be considered a valid imaging biomarker of trunk muscle composition.

Evaluation of an iterative model-based CT reconstruction algorithm by intra-patient comparison of standard and ultra-low-dose examinations

Background The explosive growth of computer tomography (CT) has led to a growing public health concern about patient and population radiation dose. A recently introduced technique for dose reduction, which can be combined with tube-current modulation, over-beam reduction, and organ-specific dose reduction, is iterative reconstruction (IR). Purpose To evaluate the quality, at different radiation dose levels, of three reconstruction algorithms for diagnostics of patients with proven liver metastases under tumor follow-up. Material and Methods A total of 40 thorax-abdomen-pelvis CT examinations acquired from 20 patients in a tumor follow-up were included. All patients were imaged using the standard-dose and a specific low-dose CT protocol. Reconstructed slices were generated by using three different reconstruction algorithms: a classical filtered back projection (FBP); a first-generation iterative noise-reduction algorithm (iDose4); and a next generation model-based IR algorithm (IMR). Results The overall detection of liver lesions tended to be higher with the IMR algorithm than with FBP or iDose4. The IMR dataset at standard dose yielded the highest overall detectability, while the low-dose FBP dataset showed the lowest detectability. For the low-dose protocols, a significantly improved detectability of the liver lesion can be reported compared to FBP or iDose⁴ ( P = 0.01). The radiation dose decreased by an approximate factor of 5 between the standard-dose and the low-dose protocol. Conclusion The latest generation of IR algorithms significantly improved the diagnostic image quality and provided virtually noise-free images for ultra-low-dose CT imaging.

Magnetic Resonance Imaging of Adipose Tissue in Metabolic Dysfunction

BACKGROUND

 Adipose tissue has become an increasingly important tissue target in medicine. It plays a central role in the storage and release of energy throughout the human body and has recently gained interest for its endocrinologic function. Magnetic resonance imaging (MRI) is an established method for quantitative direct evaluation of adipose tissue distribution, and is used increasingly as the modality of choice for metabolic phenotyping. The purpose of this review was the identification and presentation of the currently available literature on MRI of adipose tissue in metabolic dysfunction.

METHOD

 A PubMed (http://www.ncbi.nlm.nih.gov/pubmed) keyword search up to August 2017 without starting date limitation was performed and reference lists of relevant articles were searched.

RESULTS AND CONCLUSION

 MRI provides excellent tools for the evaluation of adipose tissue distribution and further characterization of the tissue. Standard as well as newly developed MRI techniques allow a risk stratification for the development of metabolic dysfunction and enable monitoring without the use of ionizing radiation or contrast material.

KEY POINTS

  · Different types of adipose tissue play a crucial role in various types of metabolic dysfunction.. · Magnetic resonance imaging (MRI) is an excellent tool for noninvasive adipose tissue evaluation with respect to distribution, composition and metabolic activity.. · Both standard and newly developed MRI techniques can be used for risk stratification for the development of metabolic dysfunction and allow monitoring without the use of ionizing radiation or contrast material..

CITATION FORMAT

· Franz D, Syväri J, Weidlich D et al. Magnetic Resonance Imaging of Adipose Tissue in Metabolic Dysfunction. Fortschr Röntgenstr 2018; 190: 1121 - 1130.

Identification of a Catalytically Highly Active Surface Phase for CO Oxidation over PtRh Nanoparticles under Operando Reaction Conditions

Pt-Rh alloy nanoparticles on oxide supports are widely employed in heterogeneous catalysis with applications ranging from automotive exhaust control to energy conversion. To improve catalyst performance, an atomic-scale correlation of the nanoparticle surface structure with its catalytic activity under industrially relevant operando conditions is essential. Here, we present x-ray diffraction data sensitive to the nanoparticle surface structure combined with in situ mass spectrometry during near ambient pressure CO oxidation. We identify the formation of ultrathin surface oxides by detecting x-ray diffraction signals from particular nanoparticle facets and correlate their evolution with the sample's enhanced catalytic activity. Our approach opens the door for an in-depth characterization of well-defined, oxide-supported nanoparticle based catalysts under operando conditions with unprecedented atomic-scale resolution.

Non-invasive Measurement of Brown Fat Metabolism Based on Optoacoustic Imaging of Hemoglobin Gradients

Metabolism is a fundamental process of life. However, non-invasive measurement of local tissue metabolism is limited today by a deficiency in adequate tools for in vivo observations. We designed a multi-modular platform that explored the relation between local tissue oxygen consumption, determined by label-free optoacoustic measurements of hemoglobin, and concurrent indirect calorimetry obtained during metabolic activation of brown adipose tissue (BAT). By studying mice and humans, we show how video-rate handheld multi-spectral optoacoustic tomography (MSOT) in the 700-970 nm spectral range enables non-invasive imaging of BAT activation, consistent with positron emission tomography findings. Moreover, we observe BAT composition differences between healthy and diabetic tissues. The study consolidates hemoglobin as a principal label-free biomarker for longitudinal non-invasive imaging of BAT morphology and bioenergetics in situ. We also resolve water and fat components in volunteers, and contrast MSOT readouts with magnetic resonance imaging data.

Associations Between Lumbar Vertebral Bone Marrow and Paraspinal Muscle Fat Compositions-An Investigation by Chemical Shift Encoding-Based Water-Fat MRI

Purpose: Advanced magnetic resonance imaging (MRI) methods enable non-invasive quantification of body fat situated in different compartments. At the level of the lumbar spine, the paraspinal musculature is the compartment spatially and functionally closely related to the vertebral column, and both vertebral bone marrow fat (BMF) and paraspinal musculature fat contents have independently shown to be altered in various metabolic and degenerative diseases. However, despite their close relationships, potential correlations between fat compositions of these compartments remain largely unclear. Materials and Methods: Thirty-nine female subjects (38.5% premenopausal women, 29.9 ± 7.1 years; 61.5% postmenopausal women, 63.2 ± 6.3 years) underwent MRI at 3T of the lumbar spine using axially- and sagittally-prescribed gradient echo sequences for chemical shift encoding-based water-fat separation. The erector spinae muscles and vertebral bodies of L1-L5 were segmented to determine the proton density fat fraction (PDFF) of the paraspinal and vertebral bone marrow compartments. Correlations were calculated between the PDFF of the paraspinal muscle and bone marrow compartments. Results: The average PDFF of the paraspinal muscle and bone marrow compartments were significantly lower in premenopausal women when compared to postmenopausal women (11.6 ± 2.9% vs. 24.6 ± 7.1% & 28.8 ± 8.3% vs. 47.2 ± 8.5%; p < 0.001 for both comparisons). In premenopausal women, no significant correlation was found between the PDFF of the erector spinae muscles and the PDFF of the bone marrow of lumbar vertebral bodies (p = 0.907). In contrast, a significant correlation was shown in postmenopausal women (r = 0.457, p = 0.025). Significance was preserved after inclusion of age and body mass index (BMI) as control variables (r = 0.472, p = 0.027). Conclusion: This study revealed significant correlations between the PDFF of paraspinal and vertebral bone marrow compartments in postmenopausal women. The PDFF of the paraspinal and vertebral bone marrow compartments and their correlations might potentially serve as biomarkers; however, future studies including more subjects are required to evaluate distinct clinical value and reliability. Future studies should also follow up our findings in patients suffering from metabolic and degenerative diseases to clarify how these correlations change in the course of such diseases.

Anatomical Variation of Age-Related Changes in Vertebral Bone Marrow Composition Using Chemical Shift Encoding-Based Water-Fat Magnetic Resonance Imaging

Assessment of vertebral bone marrow composition has been proposed as imaging biomarker for osteoporosis, hematopoietic, and metabolic disorders. We investigated the anatomical variation of age-related changes of vertebral proton density fat fraction (PDFF) using chemical shift encoding-based water-fat magnetic resonance imaging (MRI). 156 healthy subjects were recruited (age range 20-29 years: 12/30 males/females; 30-39: 15/9; 40-49: 4/14; 50-59: 9/27; 60-69: 5/19; 70-79: 4/8). An eight-echo 3D spoiled gradient-echo sequence at 3T MRI was used for chemical shift-encoding based water-fat separation at the lumbar spine. Vertebral bodies of L1-L4 were manually segmented to extract PDFF values at each vertebral level. PDFF averaged over L1-L4 was significantly (p < 0.05) higher in males than females in the twenties (32.0 ± 8.0 vs. 27.2 ± 6.0%) and thirties (35.3 ± 6.7 vs. 27.3 ± 6.2%). With increasing age, females showed an accelerated fatty conversion of the bone marrow compared to men with no significant (p > 0.05) mean PDFF differences in the forties (32.4 ± 8.4 vs. 34.5 ± 6.8%) and fifties (42.0 ± 6.1 vs. 40.5 ± 9.7%). The accelerated conversion process continued resulting in greater mean PDFF values in females than males in the sixties (40.2 ± 6.9 vs. 48.8 ± 7.7%; p = 0.033) and seventies (43.9 ± 7.6 vs. 50.5 ± 8.2%; p = 0.208), though the latter did not reach statistical significance. Relative age-related PDFF change from the twenties to the seventies increased from 16.7% (L1) to 51.4% (L4) in males and 76.8% (L1) to 85.7% (L4) in females. An accelerated fatty conversion of bone marrow was observed in females with increasing age particularly evident after menopause. Relative age-related PDFF changes showed an anatomical variation with most pronounced changes at lower lumbar vertebral levels in both sexes.

Association of proton density fat fraction in adipose tissue with imaging-based and anthropometric obesity markers in adults

Background/Objectives:

The purpose of this study was to examine the relationship of the proton density fat fraction (PDFF), measured by magnetic resonance imaging (MRI), of supraclavicular and gluteal adipose tissue with subcutaneous and visceral adipose tissue (SAT and VAT) volumes, liver fat fraction and anthropometric obesity markers. The supraclavicular fossa was selected as a typical location where brown adipocytes may be present in humans and the gluteal region was selected as a typical location enclosing primarily white adipocytes.

Subjects/Methods:

In this cross-sectional study, 61 adults (44 women, median age 29.3 years, range 21–68 years) underwent an MRI examination of the neck and the abdomen/pelvis (3T, Ingenia, Philips Healthcare). PDFF maps of the supraclavicular and gluteal adipose tissue and the liver were generated. Volumes of SAT and VAT were calculated and supraclavicular and subcutaneous fat were segmented using custom-built post-processing algorithms. Body mass index (BMI), waist circumference and waist-to-height ratio were recorded. Statistical analysis was conducted using the Student's t-test and Pearson correlation analysis.

Results:

Mean supraclavicular PDFF was 75.3±4.7% (range 65.4–83.8%) and mean gluteal PDFF was 89.7±2.9% (range 82.2-94%), resulting in a significant difference (P<0.0001). Supraclavicular PDFF was positively correlated with VAT (r=0.76, P<0.0001), SAT (r=0.73, P<0.0001), liver PDFF (r=0.42, P=0.0008) and all measured anthropometric obesity markers. Gluteal subcutaneous PDFF also correlated with VAT (r=0.59, P<0.0001), SAT (r=0.63, P<0.0001), liver PDFF (r=0.3, P=0.02) and anthropometric obesity markers.

Conclusions:

The positive correlations between adipose tissue PDFF and imaging, as well as anthropometric obesity markers suggest that adipose tissue PDFF may be useful as a biomarker for improving the characterization of the obese phenotype, for risk stratification and for selection of appropriate treatment strategies.

Quantitative MRI and spectroscopy of bone marrow

Bone marrow is one of the largest organs in the human body, enclosing adipocytes, hematopoietic stem cells, which are responsible for blood cell production, and mesenchymal stem cells, which are responsible for the production of adipocytes and bone cells. Magnetic resonance imaging (MRI) is the ideal imaging modality to monitor bone marrow changes in healthy and pathological states, thanks to its inherent rich soft‐tissue contrast. Quantitative bone marrow MRI and magnetic resonance spectroscopy (MRS) techniques have been also developed in order to quantify changes in bone marrow water–fat composition, cellularity and perfusion in different pathologies, and to assist in understanding the role of bone marrow in the pathophysiology of systemic diseases (e.g. osteoporosis). The present review summarizes a large selection of studies published until March 2017 in proton‐based quantitative MRI and MRS of bone marrow. Some basic knowledge about bone marrow anatomy and physiology is first reviewed. The most important technical aspects of quantitative MR methods measuring bone marrow water–fat composition, fatty acid composition, perfusion, and diffusion are then described. Finally, previous MR studies are reviewed on the application of quantitative MR techniques in both healthy aging and diseased bone marrow affected by osteoporosis, fractures, metabolic diseases, multiple myeloma, and bone metastases.

Level of Evidence: 3

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;47:332–353.

MR-based assessment of body fat distribution and characteristics

The assessment of body fat distribution and characteristics using magnetic resonance (MR) methods has recently gained significant attention as it further extends our pathophysiological understanding of diseases including obesity, metabolic syndrome, or type 2 diabetes mellitus, and allows more detailed insights into treatment response and effects of lifestyle interventions. Therefore, the purpose of this study was to review the current literature on MR-based assessment of body fat distribution and characteristics. PubMed search was performed to identify relevant studies on the assessment of body fat distribution and characteristics using MR methods. T1-, T2-weighted MR Imaging (MRI), Magnetic Resonance Spectroscopy (MRS), and chemical shift-encoding based water-fat MRI have been successfully used for the assessment of body fat distribution and characteristics. The relationship of insulin resistance and serum lipids with abdominal adipose tissue (i.e. subcutaneous and visceral adipose tissue), liver, muscle, and bone marrow fat content have been extensively investigated and may help to understand the underlying pathophysiological mechanisms and the multifaceted obese phenotype. MR methods have also been used to monitor changes of body fat distribution and characteristics after interventions (e.g. diet or physical activity) and revealed distinct, adipose tissue-specific properties. Lastly, chemical shift-encoding based water-fat MRI can detect brown adipose tissue which is currently the focus of intense research as a potential treatment target for obesity. In conclusion, MR methods reliably allow the assessment of body fat distribution and characteristics. Irrespective of the promising findings based on these MR methods the clinical usefulness remains to be established.

Meta-analysis of stomatitis in clinical studies of everolimus: incidence and relationship with efficacy

In a meta-analysis of clinical studies, stomatitis did not adversely affect PFS in everolimus-treated patients, and in some studies, trended toward longer PFS than in patients without stomatitis. These results support continued use of everolimus, with dose adjustments and management according to approved prescribing information.

Background

Everolimus, an oral mammalian target of rapamycin (mTOR) inhibitor, is used to treat solid tumors and tuberous sclerosis complex (TSC). Stomatitis, an inflammation of the mucous membranes of the mouth, is a common adverse event associated with mTOR inhibitors, including everolimus. We conducted a meta-analysis of data from seven randomized, double-blind phase 3 clinical trials of everolimus to determine the clinical impact of stomatitis on efficacy and safety.

Patients and methods

Data were pooled from the safety sets of solid tumor [breast cancer (BOLERO-2 and BOLERO-3), renal cell carcinoma (RECORD-1), carcinoid tumors (RADIANT-2), and pancreatic neuroendocrine tumors (RADIANT-3)] and TSC studies (EXIST-1 and EXIST-2). Data from solid tumor trials and TSC trials were analyzed separately.

Results

The rate of stomatitis was 67% in the solid tumor trials (973/1455 patients) and 70% in the TSC trials (110/157 patients). Most stomatitis events were grade 1/2, with grade 3/4 events reported in only 9% (solid tumor trials) and 8% (TSC trials) of patients. Low TSC patient numbers prevented an in-depth evaluation of stomatitis and response. In the solid tumor trials, most first stomatitis episodes (89%; n = 870) were observed within 8 weeks of starting everolimus. Patients with stomatitis occurring within 8 weeks of everolimus initiation had longer progression-free survival (PFS) than everolimus-treated patients without stomatitis in BOLERO-2 {8.5 versus 6.9 months, respectively; hazard ratio (HR), 0.78 [95% confidence interval (CI), 0.62–1.00]} and RADIANT-3 [13.9 versus 8.3 months, respectively; HR, 0.70 (95% CI, 0.48–1.04)]. A similar trend was observed in RECORD-1 [HR, 0.90 (95% CI, 0.66–1.22)] and RADIANT-2 [HR, 0.87 (95% CI, 0.61–1.22)] but not in BOLERO-3 [HR, 1.01 (95% CI, 0.75–1.36)].

Conclusions

Stomatitis did not adversely affect PFS, supporting the administration of everolimus in accordance with standard management guidelines.

[Comparison of ICD 10 and AIS with the Development of a Method for Automated Conversion]

BACKGROUND

Most of the current scores and outcome prediction calculations in traumatology are based on the Abbreviated Injury Scale (AIS). However, this is not routinely used for documentation and coding of injuries in many countries, including Germany. Instead of the AIS, the International Classification of Diseases (ICD) is used. While the ICD functions as the basis for automated calculating of the diagnosis-related groups (DRG), no possibility of simple conversion of the 10th version of the ICD into AIS is available so far.

OBJECTIVES

The aim of this work is to develop and apply a methodology for simple conversion from ICD 10 to current AIS.

MATERIALS AND METHODS

The developed mapping procedure was based on a 1 : n relationship between trauma codes of ICD-10-GM and the codes of the AIS2005. Calculated ISS from the conversion codes were then compared with the actual ISS coding available from the clinical trauma documentation.

RESULTS

It can be shown that, despite the considerable differences in the structure and systematic of both classification systems, an automated translation is technically possible.

CONCLUSIONS

The preliminary result of the mapping suggests, however, that despite the technical feasibility of a reliable conversion and comparability of ICD 10 and AIS in the required quality is still questionable. An automated conversion is still possible and quality would possibly improve by inclusion of additional information.

Automated high-throughput analysis of B cell spreading on immobilized antibodies with whole slide imaging

Automated image processing methods enable objective, reproducible and high quality analysis of fluorescent cell images in a reasonable amount of time. Therefore, we propose the application of image processing pipelines based on established segmentation algorithms which can handle massive amounts of whole slide imaging data of multiple fluorescent labeled cells. After automated parameter adaption the segmentation pipelines provide high quality cell delineations revealing significant differences in the spreading of B cells: LPS-activated B cells spread significantly less on anti CD19 mAb than on anti BCR mAb and both processes could be inhibited by the F-actin destabilizing drug Cytochalasin D. Moreover, anti CD19 mAb induce a more symmetrical spreading than anti BCR mAb as reflected by the higher cell circularity.

[Description of the severely injured in the DRG system: is treatment of the severely injured still affordable?]

BACKGROUND

Due to the heterogeneity of severely injured patients (multiple trauma) it is difficult to assign them to homogeneic diagnosis-related groups (DRG). In recent years this has led to a systematic underfunding in the German reimbursement system (G-DRG) for cases of multiply injured patients. This project aimed to improve the reimbursement by modifying the case allocation algorithms of multiply injured patients within the G-DRG system.

METHODS

A retrospective analysis of standardized G-DRG data according to §21 of the Hospital Reimbursement Act (§ 21 KHEntgG) including case-related cost data from 3,362 critically injured patients from 2007 and 2008 from 10 university hospitals and 7 large municipal hospitals was carried out. For 1,241 cases complementary detailed information was available from the trauma registry of the German Trauma Society to monitor the case allocation of multiply injured patients within the G-DRG system. Analysis of coding and grouping, performance of case allocation and the homogeneity of costs in the G-DRG versions 2008-2012 was carried out.

RESULTS

The results showed systematic underfunding of trauma patients in the G-DRG version 2008 but adequate cost covering in the majority of cases with the G-DRG versions 2011 and 2012. Cost coverage was foundfor multiply injured patients from the clinical viewpoint who were identified as multiple trauma by the G-DRG system. Some of the overfunded trauma patients had high intensive care costs. Also there was underfunding for multiple injured patients not identified as such in the G-DRG system.

CONCLUSIONS

Specific modifications of the G-DRG allocation structures could increase the appropriateness of reimbursement of multiply injured patients. Data-based analysis is an essential prerequisite for a constructive development of the G-DRG system and a necessary tool for the active participation of medical specialist societies.

[Bone substitutes - basic principles and clinical applications]

Treatment of bone defects and non-unions frequently requires the transplantation of autologous bone. As an alternative, different kinds of bone substitutes have been used more often during the past years. These bone substitutes include synthetic materials, just as well as processed materials from human donors (allogen) or animals (xenogen). The relatively low hurdles in the approval process, compared to pharmaceutical drugs, have led to an almost unmanageable amount of different kinds of bone substitutes. Due to sparse clinical studies, evidence-based decisions for a specific product or a specific indication are hardly possible. Therefore, a deeper knowledge about basic properties of different bone substitutes is needed for a rational clinical decision. The present review aims to clarify the sometimes confusing nomenclature of bone substitutes and discuss their different biological properties. Generally, bone substitutes can be discriminated in osteogenic, osteoinductive and osteoconductive materials. The great majority of bone substitutes and especially synthetic materials serve as a matrix for bone growth and therefore possess mainly osteoconductive properties. The combination of these osteoconductive materials with osteogenic cells or osteoinductive growth factors, leads to composite materials with higher bone forming potential. Clinically, the quality and vitality of the recipient bone defect is of great importance. As a prerequisite for successful transplantation of bone substitutes or autologous bone, the recipient bone defect should be mechanically stable, free of infection with vital bone ends and intact soft tissue coverage. Bone defects in the spine, methaphyseal defects after trauma/tumour and diaphyseal segmental defects are typical indications for the application of bone substitutes. Unfortunately, the current literature does not allow concrete recommendations for specific bone substitutes or specific clinical indications. However, this review aims to discuss clinical benefits and limitations of bone substitutes for frequent indications to help clinicians in their decision making process.

Mobilization of CD133+ progenitor cells in patients with acute cerebral infarction

Progenitor cells (PCs) contribute to the endogenous repair mechanism after ischemic events. Interleukin-8 (IL-8) as part of the acute inflammatory reaction may enhance PC mobilization. Also, statins are supposed to alter number and function of circulating PCs. We aimed to investigate PC mobilization after acute ischemic stroke as well as its association with inflammatory markers and statin therapy. Sixty-five patients with ischemic stroke were enrolled in the study. The number of CD133⁺ PCs was analyzed by flow cytometry. Blood samples were drawn within 24 hours after symptom onset and after 5 days. The number of CD133⁺ PCs increased significantly within 5 days (p<0.001). We found no correlation between CD133⁺ PCs and the serum levels of IL-8, IL-6, or C-reactive protein (CRP). Multivariate analysis revealed that preexisting statin therapy correlated independently with the increase of CD133⁺ PCs (p = 0.001). This study showed a mobilization of CD133⁺ PCs in patients with acute cerebral infarction within 5 days after symptom onset. The early systemic inflammatory response did not seem to be a decisive factor in the mobilization of PCs. Preexisting statin therapy was associated with the increase in CD133⁺ PCs, suggesting a potentially beneficial effect of statin therapy in patients with stroke.

Atomic structure and crystalline order of graphene-supported ir nanoparticle lattices

We present the atomic structure of Ir nanoparticles with 1.5 nm diameter at half height and three layers average height grown on graphene/Ir(111). Using surface x-ray diffraction, we demonstrate that Ir nanoparticles on graphene/Ir(111) form a crystallographic superlattice with high perfection. The superlattice arrangement allows us to obtain detailed information on the atomic structure of the nanoparticles themselves, such as size, shape, internal layer stacking and strain. Our experiments disclose that the nanoparticles reside epitaxially on top of the graphene moiré structure on Ir(111), resulting in significant lateral compressive intraparticle strain. Normal incidence x-ray standing wave experiments deliver additional information on the particle formation induced restructuring of the graphene layer.

[Orthopedic and trauma surgery in the German DRG system. Recent developments]

BACKGROUND

Orthopedics and trauma surgery are subject to continuous medical advancement. The correct and performance-based case allocation by German diagnosis-related groups (G-DRG) is a major challenge. This article analyzes and assesses current developments in orthopedics and trauma surgery in the areas of coding of diagnoses and medical procedures and the development of the 2012 G-DRG system.

METHODS

The relevant diagnoses, medical procedures and G-DRGs in the versions 2011 and 2012 were analyzed based on the publications of the German DRG Institute (InEK) and the German Institute of Medical Documentation and Information (DIMDI).

RESULTS

Changes were made for the International Classification of Diseases (ICD) coding of complex cases with medical complications, the procedure coding for spinal surgery and for hand and foot surgery. The G-DRG structures were modified for endoprosthetic surgery on ankle, shoulder and elbow joints. The definition of modular structured endoprostheses was clarified.

CONCLUSION

The G-DRG system for orthopedic and trauma surgery appears to be largely consolidated. The current phase of the evolution of the G-DRG system is primarily aimed at developing most exact descriptions and definitions of the content and mutual delimitation of operation and procedures coding (OPS). This is an essential prerequisite for a correct and performance-based case allocation in the G-DRG system.

[The challenge of adequate reimbursement for the seriously injured patient in the German DRG system]

BACKGROUND

Critically injured patients are a very heterogeneous group, medically and economically. Their treatment is a major challenge for both the medical care and the appropriate financial reimbursement. Systematic underfunding can have a significant impact on the quality of patient care. In 2009 the German Trauma Society and the DRG-Research Group of the University Hospital Muenster initialised a DRG evaluation project to analyse the validity of case allocation of critically injured patients within the German DRG system versions 2008 and 2011 with additional consideration of clinical data from the trauma registry of the German Trauma Society. Severe deficits within the G-DRG structure were identified and specific solutions were designed and realised.

METHODS

A retrospective analysis was undertaken of standardised G-DRG data (§ 21 KHEntgG) including case-related cost data from 3 362 critically injured patients in the periods 2007 and 2008 from 10 university hospitals and 7 large municipal hospitals. For 1 241 cases of the sample, complementary detailed information was available from the trauma registry of the German Trauma Society to monitor the case allocation of critically injured patients within the G-DRG system. Analyses of coding and grouping, performance of case allocation, and the homogeneity of costs in the G-DRG versions 2008 and 2011 were done.

RESULTS

The following situations were found: (i) systematic underfunding of trauma patients in the G-DRG-Version 2008, especially trauma patients with acute paraplegia; (ii) participation in the official G-DRG development for 2011 with 13 proposals which were largely realised; (ii) the majority of cases with cost-covering in the G-DRG version 2011; (iv) significant improvements in the quality of statistical criteria; (v) overfunded trauma patients with high intensive care costs; (vi) underfunding for clinically relevant critically injured patients not identified in the G-DRG system.

CONCLUSION

The quality of the G-DRG system is measured by the ability to obtain adequate case allocations for highly complex and heterogeneous cases. Specific modifications of the G-DRG structures could increase the appropriateness of case allocation of critically injured patients. Additional consideration of the ISS clinical data must be further evaluated. Data-based analysis is an essential prerequisite for a constructive development of the G-DRG system and a necessary tool for the active participation of medical societies in this process.