[The Dutch Personality Inventory for DSM-5 (PID-5-NL): psychometric properties and clinical application]. / De Nederlandstalige DSM-5 Persoonlijkheidsvragenlijst (PID-5-NL): psychometrische eigenschappen en klinische toepassing.

BACKGROUND: The Dutch Personality Inventory for DSM-5 (PID-5-NL) is the APA recommended questionnaire to assess maladaptive personality traits as defined in the Alternative DSM-5 model of personality disorders. AIM: To describe of the psychometric qualities of the PID-5-NL, present of normative data and apply the PID-5-NL in clinical practice. METHOD: The PID-5-NL was administered in a sample of adults from the general population in Flanders (Belgium) and in a sample of patients with a personality disorder in mental health care in the Netherlands. Scores on the PID-5 of a patient with borderline personality disorder are illustrated in a case vignette. RESULTS: Reliability and validity of the PID-5-NL were satisfactory to good, and comparable with results from international research on the PID-5. It was remarkable that in the current research group, patients scored as low as or even lower than the group from the general population on a number of trait facets. CONCLUSION: The PID-5-NL questionnaire is a useful tool to gain insight in a straightforward way into a wide range of relevant personality traits for diagnosis and treatment planning; provisional reference groups for the clinical practice in regular mental health care are made available on the basis of this study. Further refinement of the reference groups and further research within patients with externalizing personality problems is recommended.

Incorporating non-equilibrium dynamics into demographic history inferences of a migratory marine species.

Understanding how dispersal and gene flow link geographically separated the populations over evolutionary history is challenging, particularly in migratory marine species. In southern right whales (SRWs, Eubalaena australis), patterns of genetic diversity are likely influenced by the glacial climate cycle and recent history of whaling. Here we use a dataset of mitochondrial DNA (mtDNA) sequences (n = 1327) and nuclear markers (17 microsatellite loci, n = 222) from major wintering grounds to investigate circumpolar population structure, historical demography and effective population size. Analyses of nuclear genetic variation identify two population clusters that correspond to the South Atlantic and Indo-Pacific ocean basins that have similar effective breeder estimates. In contrast, all wintering grounds show significant differentiation for mtDNA, but no sex-biased dispersal was detected using the microsatellite genotypes. An approximate Bayesian computation (ABC) approach with microsatellite markers compared the scenarios with gene flow through time, or isolation and secondary contact between ocean basins, while modelling declines in abundance linked to whaling. Secondary-contact scenarios yield the highest posterior probabilities, implying that populations in different ocean basins were largely isolated and came into secondary contact within the last 25,000 years, but the role of whaling in changes in genetic diversity and gene flow over recent generations could not be resolved. We hypothesise that these findings are driven by factors that promote isolation, such as female philopatry, and factors that could promote dispersal, such as oceanographic changes. These findings highlight the application of ABC approaches to infer the connectivity in mobile species with complex population histories and, currently, low levels of differentiation.

Making Surgical Care Safer: A Survey on the Implementation of the Checklist by Belgian Surgeons.

BACKGROUND: The operating theatre (OT) is a complex environment. The purpose of this survey was to evaluate the implementation of the surgical checklist (SC) at individual level by Belgian Surgeons. METHODS: A Surgical Checklist Questionnaire (SCQ) related to the use of the SC by individual surgeons was attached to the registration website for the 2015 Belgian Surgical Week. It was a one page long, user friendly document, easy to be filled voluntarily and anonymously. RESULTS: Among the 206 surgeons who registered, 81 (39%) filled in the SCQ. The SC template proposed by the WHO "Safe Surgery Saves Lives" initiative was used by 91% of the respondents. However, 89% adapted the SC to their local hospital environment, and 87.5% use it personally for their patients. Since implementation, the SC was never adapted in 46%. According to 21% of respondents, an adverse event was avoided thanks to the SC. Amazingly, SC was considered as an administrative burden by 83% despite the same percentage recognized that patients benefited from the SC. Only 28% of respondents got feedback from the use of the SC. CONCLUSIONS: In this survey, the number of adverse event avoided thanks to the use of the SC demonstrates that SC -represents a simple strategy for addressing surgical patient safety in OT. Nevertheless, SC is still considered by many surgeons as an additional administrative burden and/or as just another gimmick. Further studies are needed to understand why some surgeons are still not willing to adapt to a changing safety culture.

In vitro expansion of U87-MG human glioblastoma cells under hypoxic conditions affects glucose metabolism and subsequent in vivo growth.

Hypoxia is a characteristic feature of solid tumors leading to the over expression of hypoxia-inducible factor (HIF)-1α protein and therefore to a specific cellular behavior. However, even though the oxygen tension in tumors is low (<5 %), most of the cell lines used in cancer studies are grown under 21 % oxygen tension. This work focuses on the impact of oxygen conditions during in vitro cell culture on glucose metabolism using 1-(13)C-glucose. Growing U87-MG glioma cells under hypoxic conditions leads to a two- to threefold reduction of labeled glutamine and an accumulation of fructose. However, under both hypoxic and normoxic conditions, glucose is used for de novo synthesis of pyrimidine since the (13)C label is found both in the uracil and ribose moieties. Labeling of the ribose ring demonstrates that U87-MG glioma cells use the reversible branch of the non-oxidative pentose phosphate pathway. Interestingly, stereotactic implantation of U87-MG cells grown under normoxia or mild hypoxia within the striatum of nude mice led to differential growth; the cells grown under hypoxia retaining an imprint of the oxygen adaptation as their development is then slowed down.

Modeling nigrostriatal degeneration in organotypic cultures, a new ex vivo model of Parkinson's disease.

Parkinson's disease (PD) is the second most frequent neurodegenerative disorder afflicting 2% of the population older than 65 years worldwide. Recently, brain organotypic slices have been used to model neurodegenerative disorders, including PD. They conserve brain three-dimensional architecture, synaptic connectivity and its microenvironment. This model has allowed researchers a simple and rapid method to observe cellular interactions and mechanisms. In the present study, we developed an organotypic PD model from rat brains that includes all the areas involved in the nigrostriatal pathway in a single slice preparation, without using neurotoxins to induce the dopaminergic lesion. The mechanical transection of the nigrostriatal pathway obtained during slice preparation induced PD-like histopathology. Progressive nigrostriatal degeneration was monitored combining innovative approaches, such as diffusion tensor magnetic resonance imaging (DT-RMI) to follow fiber degeneration and mass spectrometry to quantify striatal dopamine content, together with bright-field and fluorescence microscopy imaging. A substantia nigra dopaminergic cell number decrease was observed by immunohistochemistry against rat tyrosine hydroxylase (TH) reaching 80% after 2 days in culture associated with a 30% decrease of striatal TH-positive fiber density, a 15% loss of striatal dopamine content quantified by mass spectrometry and a 70% reduction of nigrostriatal fiber fractional anisotropy quantified by DT-RMI. In addition, a significant decline of medium spiny neuron density was observed from days 7 to 16. These sagittal organotypic slices could be used to study the early stage of PD, namely dopaminergic degeneration, and the late stage of the pathology with dopaminergic and GABAergic neuron loss. This novel model might improve the understanding of PD and may represent a promising tool to refine the evaluation of new therapeutic approaches.

Perfluorocarbon-loaded lipid nanocapsules as oxygen sensors for tumor tissue pO2 assessment.

The assessment of tumor oxygenation is a crucial factor in cancer therapy and may be carried out using fluorine MRI once fluorine probes have been distributed within the tumor. However, the deposit of those highly fluorinated compounds often jeopardizes anatomical image quality and requires emulsification of the probes. Due to the high density and the high lipophilicity of perfluorocarbons, nanoemulsion of these molecules usually requires high-energy processes. In the present work, we discuss the synthesis and the physico-chemical characterization of perfluorocarbon nanocapsules using a low-energy phase-inversion process. The nanocapsules were tested on a mouse tumor brain model to assess oxygenation.

Susceptibility gradient quantization by MRI signal response mapping (SIRMA) to dephaser.

PURPOSE: Susceptibility effects are a very efficient source of contrast in magnetic resonance imaging. However, detection is hampered by the fact the induced contrast is negative. In this work, the SIgnal Response MApping (SIRMA) to dephaser method is proposed to map susceptibility gradient to improve visualization. METHODS: In conventional gradient echo acquisitions, the echo formation of susceptibility affected spins is shifted in k-space, the shift being proportional to the susceptibility gradient. Susceptibility gradients map can be produced by measuring this induced shifts. The SIRMA method measures these shifts from a series of dephased images collected with additional incremental dephasers. These additional dephasers correspond either to a slice refocusing gradient offset or to a reconstruction window off-centering. The signal intensity profile as a function of the additional dephaser was determined on a pixel-by-pixel basis from the ensemble of dephased images. Susceptibility affected voxels presented a signal response profile maximum shifted compared to nonaffected voxels ones. Shift magnitude and sign were measured for each pixel to determine susceptibility gradients and produce a susceptibility gradient map. RESULTS: In vitro experiments demonstrated the ability of the method to map gradient inhomogeneities induced by a cylinder. Quantization accuracy was evaluated comparing SIRMA images and simulations performed on the well-characterized air filled cylinder model. Performances of the SIRMA method, evaluated in vitro on cylinders filled with various superparamagnetic iron oxide SPIO concentrations, showed limited influence of acquisition parameters. Robustness of the method was then assessed in vivo after an infusion of SPIO-loaded nanocapsules into the rat brain using a convection-enhanced drug delivery approach. The region of massive susceptibility gradient induced by the SPIO-loaded nanocapsules was clearly delineated on SIRMA maps and images were compared to T2* weighted images, Susceptibility Gradient Map (SGM), and histological Perl's staining slice. The potential for quantitative evaluation of SPIO distribution volume was demonstrated. CONCLUSIONS: The proposed method is a promising technique for a wide range of applications especially in molecular or cellular imaging with respect to its quantitative nature and its computational simplicity.

188Re-loaded lipid nanocapsules as a promising radiopharmaceutical carrier for internal radiotherapy of malignant gliomas.

PURPOSE: Lipid nanocapsules (LNC) entrapping lipophilic complexes of (188)Re ((188)Re(S(3)CPh)(2)(S(2)CPh) [(188)Re-SSS]) were investigated as a novel radiopharmaceutical carrier for internal radiation therapy of malignant gliomas. The present study was designed to evaluate the efficacy of intra-cerebral administration of (188)Re-SSS LNC by means of convection-enhanced delivery (CED) on a 9L rat brain tumour model. METHODS: Female Fischer rats with 9L glioma were treated with a single injection of (188)Re-SSS LNC by CED 6 days after cell implantation. Rats were put into random groups according to the dose infused: 12, 10, 8 and 3 Gy in comparison with blank LNC, perrhenate solution (4 Gy) and non-treated animals. The radionuclide brain retention level was evaluated by measuring (188)Re elimination in faeces and urine over 72 h after the CED injection. The therapeutic effect of (188)Re-SSS LNC was assessed based on animal survival. RESULTS: CED of (188)Re perrhenate solution resulted in rapid drug clearance with a brain T (1/2) of 7h. In contrast, when administered in LNC, (188)Re tissue retention was greatly prolonged, with only 10% of the injected dose being eliminated at 72 h. Rat median survival was significantly improved for the group treated with 8 Gy (188)Re-SSS LNC compared to the control group and blank LNC-treated animals. The increase in the median survival time was about 80% compared to the control group; 33% of the animals were long-term survivors. The dose of 8 Gy proved to be a very effective dose, between toxic (10-12 Gy) and ineffective (3-4 Gy) doses. CONCLUSIONS: These findings show that CED of (188)Re-loaded LNC is a safe and potent anti-tumour system for treating malignant gliomas. Our data are the first to show the in vivo efficacy of (188)Re internal radiotherapy for the treatment of brain malignancy.

Setting priorities for improving the preoperative assessment clinic: the patients' and the professionals' perspective.

BACKGROUND: The quality of the preoperative assessment clinic (PAC) is determined by many factors. Patients' experiences are important indicators, but often overlooked. We prepare to set priorities to improve the PAC by obtaining detailed patients' feedback on the quality of the PAC, and establishing the value patients and professionals attach to different care aspects, using the Patient Experiences with the Preoperative Assessment Clinic questionnaire. METHODS: The PAC's standard of service was determined for five care aspects (dimensions), using patients' feedback. The importance of a dimension to patients was determined by calculating the effects of the dimensions on patients' overall appraisal. In addition, professionals were asked to rate the importance of the different care aspects. RESULTS: Patients had the most positive experiences with the nurse, and the least positive experiences with waiting. However, waiting was least important to patients. When combining the PAC's standard of service with the value given to the dimensions by patients and professionals separately, we found in both instances that waiting was in greatest need of improvement. This was followed by reception, the anaesthetist, remaining experiences, and finally the nurse. CONCLUSIONS: Quality improvement of the PAC can be achieved by obtaining patients' feedback on the quality, determine a PAC's standard of service, recognize service areas that require improvement, and identify actions appropriate to bring about improvement. The value patients and professionals attach to different aspects of care can then be used to prioritize improvements.

Patient flow in the preoperative assessment clinic.

BACKGROUND AND OBJECTIVE: Previous research has shown that a preoperative assessment clinic enhances hospital cost-efficiency. However, the differences in organization of the patient flow have not been analysed. In this descriptive study, we evaluated the consequences of the organization of the patient flow of a preoperative assessment clinic on its performance, by analysing two Dutch university hospitals, which are organized essentially differently. METHODS: In the final analysis, the study included 880 patients who visited either academic centre. The performance of the two preoperative assessment clinics was evaluated by measuring patient flow time, various procedure times and the total waiting time. Patients' age, ASA physical status and any preoperative tests requested by the physician were also recorded. RESULTS: There was a significant difference in patient flow time between the two preoperative assessment clinics. More time was needed for the preoperative assessment when patients' ASA class was higher. The patient flow time was longer when electrocardiogram and venepuncture were performed at the general outpatient laboratory than when they were performed at the preoperative assessment clinic due to longer waiting times. More tests were requested when they were performed at the preoperative assessment clinic. CONCLUSIONS: This study shows that the organization of patient flow is an important aspect of the logistic processes of the preoperative assessment clinic. It might influence patient flow times as well as the number of preoperative tests requested. Together with other aspects of logistic performance, patient satisfaction and quality of medical assessment, patient flow logistics can be used to assess the quality of a preoperative assessment clinic.

Simulation to analyse planning difficulties at the preoperative assessment clinic.

BACKGROUND: Little research has been performed on designing appointment systems for the preoperative assessment clinic (PAC). We aimed to investigate how two organizational planning difficulties, (i) long access times and (ii) long waiting times, could be analysed systematically. METHODS: Two simulation models were used to test different scenarios to reduce access time and waiting times. First, we determined the number of appointments needed to reduce the access time from 5 weeks to 10 working days for 95% of all patients. Subsequently, we determined how long the consultation time should be, taking patients' American Society Anesthesiologists (ASA) physical status into account, to reduce the maximum waiting time to 10 min for 95% of all patients. RESULTS: Although we found the actual capacity, that is, consultations per day, to be enough to meet demand, a backlog existed, as the access time for the PAC was 5 weeks. A temporary extra capacity is needed to eliminate this backlog. When the reserved consultation time is 18 min for patients with ASA class I or II and 30 min for patients with ASA class III or IV, the maximum waiting times decrease to 10 min for 95% of all patients. CONCLUSIONS: This study shows that a simulation model is a helpful tool to determine the capacity needed to achieve and to maintain a proposed service level for access times and waiting times. In addition, waiting times at the PAC can be reduced by making the reserved consultation time dependent on patients' ASA physical status.

Patient Experiences with the Preoperative Assessment Clinic (PEPAC): validation of an instrument to measure patient experiences.

BACKGROUND: Presently, no comprehensive and validated questionnaire to measure patient experiences of the preoperative assessment clinic (PAC) is available. We developed and validated the Patient Experiences with the Preoperative Assessment Clinic (PEPAC) questionnaire, which can be used for quantitative measurements of patient experiences of the PAC. METHODS: We adapted the National Health Service outpatient questionnaire, incorporating questions specific for anaesthesiology. To make the PEPAC appropriate for quantitative measurements, dimensions and single items suitable for statistical analysis were constructed. Each dimension consists of multiple items measuring the same aspect of care. Reliability was established by computing Cronbach's alpha coefficients. Construct validity was assessed by correlating the dimensions with the patient's overall appraisal (Pearson's r). These dimensions should explain a substantial level of variance of the patients' overall appraisal; therefore, regression analysis was performed. RESULTS: After a pilot phase, the questionnaire was sent to 700 consecutive patients (response 74%). Five scales measuring five dimensions of patient experiences were constructed. Cronbach's alpha ranged from 0.56 to 0.84, supporting reliability of the PEPAC. Correlations between the dimensions and patients' overall appraisal ranged from 0.22 to 0.56. Collectively, the five scales explained 51% of patients' overall appraisal. CONCLUSIONS: The PEPAC is a comprehensive, reliable, and validated questionnaire to measure patient experiences with the PAC. It might be a useful tool to identify the service areas of the PAC that require improvement and to determine which actions can bring about improvement.

Evaluating SPIO-labelled cell MR efficiency by three-dimensional quantitative T2* MRI.

An in vitro MR-assay for superparamagnetic iron oxide (SPIO) particle cell labelling assessment via three-dimensional quantitative T(2) (*) MR microscopy was proposed. On high-resolution images, and due to the high susceptibility difference between the particles and the surrounding medium, SPIO internalized in cells induces signal loss which may be counted and measured on T(2) (*) maps. The increase in both labelled cell percentage and the average perturbation volume with an added amount of iron in the incubation medium proved that intracellular iron uptake is dependent upon the initial concentration of incubation iron. It also proved that the observed increases in total cellular iron uptake measured by inductively coupled plasma optical emission spectroscopy are due to both an increase in the iron mass per cell and also an increase in labelled cell concentration. MR results were compared with Prussian blue staining histology. The sensitivity of the MR methodology was then used to distinguish labelling differences for two different types of particle coating. The MRI-assay we proposed is a compulsory tool to optimize labelling efficiency in order to improve in vivo cell detection. Key parameters for detection, such as the percentage of cell labelling, the effect on the image for a given amount of internalized iron and labelling distribution among a cell population, are easily obtained. The comparison of different contrast agents for labelling one cell type, the assessment of one type of contrast agent for labelling different cell types and/or the evaluation of labelling strategies, are possible without having recourse to classical methods, and provide improved accuracy, since the principle is based on intracellular relaxivity.

Volumetric assessment of myocardial viability in rats using 3D double contrast enhanced T1 and T2-weighted MRI.

OBJECTIVE: Volumetric evaluation of the myocardial viability post-infarction in rats using 3D in vivo MR imaging at 7 T using injection of an extracellular paramagnetic contrast agent and intravascular superparamagnetic iron oxide nanoparticles in the same imaging session. MATERIALS AND METHODS: Five hours after induction of permanent myocardial infarction in rats (n=6), 3D in vivo T1- and T2-weighted MR Imaging was performed prior to and after Gd-DOTA injection (0.2 mmol/kg) and prior to and after nanoparticle injection (5 mg Fe/kg) to assess infarct size and myocardial viability. RESULTS: 3D MR Imaging using a successive contrast agent injection showed a difference of infarct size after Gd-DOTA injection on T1-weighted images compared to the one measured on T2-weighted images after Gd-DOTA and nanoparticle injection. CONCLUSION: The use of 3D T1- and T2-weighted MR Imaging using a double contrast agents protocol made possible the accurate characterization of myocardial infarction volume and allowed the detection of myocardial viability post-infarction in rats.

Prenatal evaluation of kidney function in mice using dynamic contrast-enhanced magnetic resonance imaging.

Glomerular differentiation starts as soon as embryonic stage 12 in mice and suggests that kidneys may be functional at this stage. Dynamic contrast-enhanced magnetic resonance microscopy, a noninvasive imaging technique, was used to assess renal function establishment in utero. Indeed, in adults (n = 3), an intravenous injection of gadolinium-DOTA induced in a first step a massive and rapid drop in kidney signal intensity followed, in a second step, by a drop in bladder signal intensity. The delay in signal changes between kidney and bladder reflected glomerular filtration. Pregnant mice underwent anatomical and dynamic contrast-enhanced magnetic resonance microscopy on postcoital days 12-13 (n = 2), 13-14 (n = 1), 14-15 (n = 3), 15-16 (n = 2), 16-17 (n = 3), 17-18 (n = 3), and 18-19 (n = 1). Kidneys and bladder were unambiguously depicted prior to contrast agent injection on stage 15-16 embryos. Contrast agent injection allowed kidney, detection as early as stage 12-13 but not bladder. Kinetics of signal changes demonstrated that glomerular filtration is established at embryonic stage 15-16 in mice. Thus, anatomical and dynamic contrast-enhanced magnetic resonance microscopy may be a powerful noninvasive method for in vivo prenatal developmental and functional studies.

Characterization and detection of experimental rat gliomas using magnetic resonance imaging.

Two different experimental rat brain tumours (F98 glioma and 9L glioma) were characterized using T1 and T2, apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR). Even though both tumours appeared homogenous at the early stage of growth, significant differences were measured for all parametric images between tumours and normal brain tissue. Irrespective of the sequence used, tumour lesion/normal parenchyma contrast for the non-infiltrative 9L was twice that of the infiltrative F98 glioma. The use of spin preparation via an inversion pulse in a fast spin echo sequence increases contrast by a factor of 20-30.

Therapeutic efficacy study of novel 5-FU-loaded PMM 2.1.2-based microspheres on C6 glioma.

The aim of this study was to evaluate the potential of poly(methylidene malonate 2.1.2) as a new drug delivery system to the central nervous system. 5-Fluorouracil microspheres were formulated by an emulsion-extraction method, and evaluated on a C6 glioma model. Twenty-seven Sprague-Dawley female rats underwent implantation of various C6 cell concentrations. Magnetic resonance imaging was performed at day 10 to control the setting of the tumor, by using a T2-weighted sequence. At day 12, 18 animals received blank or 5-FU-loaded microspheres, while 9 animals were not implanted and constituted the controls. Thereafter, MRI was performed twice a week to follow the tumor growth. In 12 animals, an alloimmune rejection of the tumor was observed, showing the limitations of the C6 glioma model. When tumor developed, no relationship was observed between the number of C6 cells injected and the tumor volume. 5-FU microsphere efficacy could statistically be demonstrated by significantly improving the median survival of C6 glioma-bearing animals and also by decreasing tumor burden.

High field magnetic resonance imaging evaluation of superparamagnetic iron oxide nanoparticles in a permanent rat myocardial infarction.

RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate superparamagnetic iron oxide (SPIO) nanoparticles to discriminate infarcted from normal tissue after myocardial infarction using high field MR imaging (7 tesla). MATERIALS AND METHODS: Permanent myocardial infarction was induced in rats. SPIO nanoparticles (1 mg Fe/kg) were assessed with T1-weighted gradient echo sequence to visualize the myocardial infarction 48 hours after ligature (n = 6). Furthermore, MR Imaging was performed using a T2-weighted RARE sequence and nanoparticles were injected (5 or 10 mg Fe/kg) on 36 rats 5, 24 or 48 hours after infarction. RESULTS: No changes in contrast between normal and infarcted myocardium was observed after nanoparticle injection on T1-weighted images. However, nanoparticles induced a significant contrast increase between normal and infarcted myocardium on T2-weighted images whatever the delay between infarction and imaging (2.99 +/- 1.66 preinjection vs. 7.82 +/- 1.96 after SPIO injection at a dose of 5 mg Fe/kg 5 hours postinfarction, P = 0.0001). CONCLUSIONS: Nanoparticle injection made it possible to discriminate normal from infarcted myocardium on T2-weighted images. However, the high magnetic field prevented the visualization of the T1 effect of SPIO nanoparticles.

Quantitative MR renography using a calibrated internal signal (ERETIC).

To measure MR renograms, cortical and medullary kidney signal intensity evolution is followed after contrast agent injection. To obtain an accurate quantitative signal measurement, the use of a reference signal is necessary to correct the potential MRI system variations in time. The ERETIC method (Electronic Reference To access In vivo Concentrations) provides an electronic reference signal. It is synthesized as an amplitude modulated RF pulse applied during the acquisition. The ERETIC method was as precise as the external tube reference method but presents major advantages like its free adjustability (shape, location and magnitude) to the characteristics of the organ studied as well as its not taking room inside the magnet. Even though ERETIC showed a very good intrinsic stability, systems' variations still affect its signal in the same way as real NMR signals are affected. This method can be easily implemented on any imaging system with two RF channels.

In utero time-course assessment of mouse embryo development using high resolution magnetic resonance imaging.

Magnetic resonance microscopy, a non-invasive imaging technique was used for a longitudinal follow-up of mouse embryonic development in utero and for the assessment of embryonic kidney function using 50 nm magnetite dextran particles. Even though the morphologic proton images obtained were still far from classical histological slices quality, an in-plan resolution of 195 microm was achieved for a slice thickness of 800 microm. Mouse embryos sub-structures such as the fourth ventricle, the mesencephalic vesicle, the aorta or the liver can be revealed as early as E11/12. Heart, diaphragm, spinal cord, third, fourth and lateral ventricles were unambiguously seen at E13/14; whereas skeleton, tail, kidney and digit can only be seen from E15/16. Kidney and bladder were certainly identified from E16 on. MR microscopy offers a possibility for in utero phenotyping of mice and can therefore be a powerful tool for post-genomic applications.