Melting of iron at Earth's inner core boundary based on fast X-ray diffraction.

Earth's core is structured in a solid inner core, mainly composed of iron, and a liquid outer core. The temperature at the inner core boundary is expected to be close to the melting point of iron at 330 gigapascal (GPa). Despite intensive experimental and theoretical efforts, there is little consensus on the melting behavior of iron at these extreme pressures and temperatures. We present static laser-heated diamond anvil cell experiments up to 200 GPa using synchrotron-based fast x-ray diffraction as a primary melting diagnostic. When extrapolating to higher pressures, we conclude that the melting temperature of iron at the inner core boundary is 6230 ± 500 kelvin. This estimation favors a high heat flux at the core-mantle boundary with a possible partial melting of the mantle.

Diagnostic precision of image-guided multisampling core needle biopsy of suspected lymphomas in a primary care hospital.

We evaluated the diagnostic quality of image-guided multisampling core needle biopsy (CNB) in patients investigated for suspected lymphoma in a primary care hospital. A total of 112 patients were consecutively assessed during a 3-year period. There were 80 lymphoid site biopsies and 32 non-lymphoid site biopsies. Eight to nine cores were obtained from different parts of the biopsy site. Two cores were systematically frozen, allowing for further morphological, immunochemistry and molecular studies. The diagnostic yield of CNB for malignancy was 100%. Only 47% (41/87) of patients with initial suspicion of lymphoma were finally diagnosed with Lymphoma. The diagnostic yield of CNB for lymphoma typing was 98% (62/63), according to the WHO classification. The diagnostic yield of CNB for complete lymphoma subtyping/grading was 86% (54/63). The diagnostic yield of CNB for a definite diagnosis of benignity was only 47% (8/17). In a primary care setting, multisampling CNB is a minimally invasive, and very accurate procedure for confirming malignancy in patients with suspected lymphoma, presenting with superficial/deep-seated, lymphoid/non-lymphoid site targets. With a very high diagnostic yield for lymphoma typing and a high diagnostic yield for complete lymphoma subtyping/grading a therapeutic decision can be taken in most patients.

[Laparoscopy in the management of endometrial cancer]. / Place de la laparoscopie dans le traitement du cancer de l'endomètre.

Recent advance in laparoscopy have changed the surgical approach of endometrial cancer patients. The Swissendos Center, Fribourg, in collaboration with AGO (Groupe de travail pour la gynécologie oncologique) and AGE (groupe de travail pour la gynécologie endoscopique) have established a consensus based on the available evidence for the use of laparoscopy in the management of patients with endometrial cancer The main objective was to define Swiss clinical practice guidelines appropriate to the country and consistent with the needs of the physicians.

[Gross tumor volume and clinical target volume in radiotherapy: lung cancer]. / Volume tumoral macroscopique et volume-cible anatomoclinique en radiothérapie: cancer bronchique.

Radiotherapy plays a major role as a curative treatment of various stages non-small cell lung cancers (NSCLC): as an exclusive treatment in curative attempt for patients with unresectable stages I and II; as a preoperative treatment, which is often associated with chemotherapy, for patients with surgically stage IIIA NSCLC in clinical trials; in association with chemotherapy for unresectable stages IIIA and IIIB patients. Currently, three-dimensional conformal radiotherapy allows for some dose escalation, increasing radiation quality. However, the high inherent conformality of this radiotherapy technique requires a rigorous approach and an optimal quality of the preparation throughout the treatment procedure and specifically of the accurate definition of the safety margins (GTV, CTV...). Different questions remain specific to lung cancers: 1) Despite the absence of randomized trials, the irradiated lymph nodes volume should be only, for the majority of the authors, the visible macroscopically involved lymph nodal regions. However, local control remains low and solid arguments suggest the poor local control is due to an insufficient delivered dose. Therefore the goal of radiotherapy, in this particular location, is to improve local control by increasing the dose until the maximum normal tissue tolerance is achieved, which essentially depends on the dose to the organs at risk (OAR) and specifically for the lung, the esophagus and the spinal cord. For this reason, the irradiated volume should be as tiny as possible, leading to not including the macroscopically uninvolved lymph nodes regions in prophylactic view in the target volume; 2) The lung is one of the rare organs with extensive motion within the body, making lung tumors difficult to treat. This particular point is not specifically considered in the GTV and CTV definitions but it is important enough to be noted; 3) When radiation therapy starts after a good response to chemotherapy, the residual tumoral volume should be defined as the target volume in place of the initial tumor volume. These different elements are discussed in this paper.

[Imaging of lung cancer: role of radiology]. / Imagerie du cancer pulmonaire: place de la radiologie.

The aim of this review is to discuss the imaging available for diagnostic, therapy and follow-up for lung cancer management.

Using thoracic helical CT to assess iodine concentration in a small volume of nonionic contrast medium during vascular opacification: a prospective study.

OBJECTIVE: The goal of the study was to assess whether, using thoracic helical CT, diagnostic mediastinal and hilar vascular enhancement can be obtained with a small amount of nonionic contrast material (80 ml) injected at a relatively slow rate (2 ml/sec). SUBJECTS AND METHODS: One hundred twenty patients (60 in their fourth decade of life and 60 in their seventh decade of life) referred for contrast-enhanced thoracic CT for malignancies or infections prospectively entered the study. They were randomly assigned to be given one of three iodine concentrations of a nonionic contrast material: 250 mg/ml (1250), 300 mg/ml (1300), and 350 mg/ml (1350). Two radiologists independently graded perivenous artifacts and arterial enhancement of mediastinal and hilar vessels on a 4-point scale: 1, poor; 2, fair; 3, good; and 4, excellent. Measurements of arterial attenuation values (quantitative assessment) were obtained on the aorta and pulmonary artery. RESULTS: Mean scores were equal to or greater than 3 for all vessels only using 1350. The higher the iodine concentration was, the higher the mean score, but there was a statistically significant difference only between scores obtained with 1350 and those obtained with 1300 or 1250. Mean scores were higher for the patients in their seventh decade of life than those in their fourth decade; however, there was no statistically significant difference between scores of the two decade groups. We found a highly significant statistical relationship between scores and arterial attenuation values. CONCLUSION: During contrast-enhanced helical CT examinations for general thoracic evaluations, good opacification of central vascular structures is obtained with a low volume of high iodine concentration nonionic contrast medium.

[Conformal radiotherapy of non-small-cell lung cancer]. / La radiothérapie conformationnelle du cancer bronchique non à petites cellules.

About one third of lung cancers initially present with a localised disease, without any curative surgery potential, because of local spread or comorbidity. Definitive radiation, alone or combined with chemotherapy, then represents the treatment of choice for these patients. The results, however, are disappointing, with a biopsy-proven local control of 10% at two years and a 5-10% five-year survival rate. These poor results may be partially explained by the difficulties in delineating the tumour volume as well as the dose limitations due to poor tolerance of surrounding normal organs. Lung parenchyma sequelae remain daily worrying events for the oncologist. The advent of 3D conformal radiation therapy (3DRT) allows progress and innovations, including the use of modern imaging techniques, sophisticated dosimetry and treatment planning, efficient immobilisation devices and on-line verification procedures. With more precise (and time-consuming) procedures, 3DRT will allow a better tumour volume delineation, an increased tumour dose and a dose limitation in normal tissues. These improvements may help increase local control and survival results. 3DRT, which has been used for several years for prostate cancer and benefits from recent imaging improvements, will now allow treatment of other locations, such as lung cancer, with conformal therapy. The few preliminary results are encouraging. This work reviews the current data and remaining questions regarding lung cancer treated with 3DRT, and presents and discusses the literature before discussing future trends in this area.

Three-dimensional phase contrast MR cerebral venography with zero filling interpolation in the slice encoding direction.

The purpose of this study was to evaluate the magnetic resonance (MR) cerebral venography findings of a three-dimensional phase contrast MR sequence with zero filling interpolation of the data in the slice encoding direction. Fifty volunteers were enrolled in the study. Images were obtained on a 1.5 MR imaging system with acquisition time of 12 min. MIP images were reconstructed throughout the entire imaging volume. A grading scale system was used to assess dural venous sinuses, major deep veins, cortical, and cortical eponymic veins. Inferior group of dural venous sinuses, inferior sagittal sinus, and cortical eponymic veins were poorly demonstrated. Score of the superior sagittal sinus, the straight sinus, the confluence of the superior sinus group, the right transverse and sigmoid sinuses, the internal veins, and the vein of Galen was excellent. The score of the left transverse and sigmoid sinuses was good. In conclusion, when using zero filling interpolation of the data in a three-dimensional phase contrast MR cerebral venography sequence, the superior group of dural venous sinuses and main major deep veins are demonstrated with good conspicuity.

Assessment of iron oxide particles (AMI 227) and a gadolinium complex (Gd-DOTA) in dynamic susceptibility contrast MR imagings (FLASH and EPI) in a tumor model implanted in rats.

The objective of our study was to assess the feasibility of dynamic susceptibility contrast MR technique after bolus injection of SPIO and Gd-DOTA in a tumor model implanted in rats. Tumors were subcutaneously implanted in 24 rats. A FLASH sequence and EPI were evaluated. Different doses of AMI 227 and Gd-DOTA were assessed. Mean signal intensity vs. time curves were plotted. Well-shaped curves of the first pass of the contrast agent were only obtained with Gd-DOTA. According to these results it appears difficult to assess tumor blood volume with USPIO dynamic susceptibility contrast imaging.

Comparison of iron oxide particles (AMI 227) with a gadolinium complex (Gd-DOTA) in dynamic susceptibility contrast MR imagings (FLASH and EPI) for both phantom and rat brain at 1.5 Tesla.

The goal of the study was to compare, in phantom and normally perfused rat brain tissue, a superparamagnetic iron oxide particle-based contrast agent (AMI 227) with a low-molecular-weight gadolinium chelate, gadolinium tetraazacyclododecanetetraacetic acid (Gd-DOTA), in two susceptibility contrast magnetic resonance imaging (MRI) modes [fast low-angle shot sequence (FLASH) and echoplanar imaging (EPI)]. A phantom consisting of dilution series of both contrast agents was manufactured. Dilutions were obtained with isotonic serum from the available agent solutions (0.5 mmol Gd/mL Gd-DOTA; 350 mumol Fe/mL AMI 227). Eighteen rats were studied. Contrast agent (0.1 mL) was bolus injected in each rat, and dynamic MRI was performed (first pass of the contrast agent) in rat brain. The doses of AMI 227 injected were extrapolated from the phantom experiment: 0.2 mmol/kg body weight of Gd-DOTA and 7, 14, and 28 mumol Fe/kg body weight of AMI 227 were injected. For both sequences, signal-to-noise ratios (S/N) were measured on each tube of the phantom and on rat brain from each image of the dynamic imaging. S/N was plotted versus contrast dilution (phantom) and versus time (rats). In the FLASH sequence, a well-shaped curve (S/N decrease, S/N peak decrease, S/N increase) of the first pass of the contrast agent was demonstrated for Gd-DOTA and for AMI 227 (7 mumol Fe/kg body weight). In the EPI sequence, a well-shaped curve was demonstrated for Gd-DOTA, and a plateau effect was noted for both concentrations of AMI 227. With the FLASH technique, dynamic susceptibility contrast imaging of rat brain can be performed with very low concentrations of AMI 227 compared with the Gd-DOTA concentration (0.2 mmol Gd/kg body weight) used in clinical practice. This could be of interest in perfusion imaging, because it may allow for first-pass susceptibility imaging after administration of a small volume in a narrow bolus.

[Radiotherapy for non-small-cell bronchial cancers: definitions of volumes, patient selection. Recommendations of the International Association for the Study of Lung Cancer (IASLC)]. / Radiothérapie du cancer bronchique non à petites cellules: définitions des volumes, sélection des patients. Recommandations de l'International Association for the Study of Lung Cancer (IASLC) Workshop, Annecy 1998.

Chemoradiation is the standard treatment of unresectable, locally advanced non-small cell lung cancer, with a mean dose of 60-66 Gy, excluding escalation dose schemes. The standard treated volume includes primary tumor, ipsilateral hilar and mediastinal nodes, supraclavicular and contralateral nodes as well, regardless of the node status. This work tries to answer the question of the optimal volume to be treated. Drainage routes analysis is in favor of large volumes, while toxicity analysis favors small volumes. Combined modality treatment may increase the observed toxicity. The optimal volume definition is difficult, and requires available conformal therapy tools. Patients selection is another important issue. A volume definition is then attempted, based on the IASLC (International Association for the Study of Lung Cancer) Annecy workshop experience, highlighting the interobservers discrepancies, and suggests basic recommendations to harmonize volume definition.

Ultrasmall superparamagnetic iron oxide particles (AMI 227) as a blood pool contrast agent for MR angiography: experimental study in rabbits.

The purpose of this study was to evaluate the contribution of an ultrasmall superparamagnetic iron oxide particles (USPIOs) based contrast agent (AMI 227), in a transverse three-dimensional time-of-flight TONE MR angiography sequence of abdominal aorta in rabbits. The main goal was to assess improvement in the visualization of small arteries such as renal arteries, when using such a sequence. Imaging experiments were performed on a 1.5 T magnet, using a transverse 3D time-of-flight (TOF) tilted optimized nonsaturating excitation (TONE) sequence with magnetization transfer suppression. The contrast media used were composed of a USPIO core surrounded by a dextran-surfactant (AMI 227). Different concentrations of AMI 227 were evaluated in 12 rabbits. Concentrations varied within the range 8.5-34 micromol Fe/kg - bw: 8.5 micromol Fe/kg (three rabbits); 17 micromol Fe/kg (three rabbits); 25.5 micromol Fe/kg (three rabbits); 34 micromol Fe/kg (three rabbits). A visual analysis based on the improvement of visualization of small arteries (renal arteries) on MIP images and a quantitative analysis based on the percentage of contrast enhancement of the aorta plotted against distance in the slab from the top edge of the acquisition volume were obtained. A signal-to-noise ratio enhancement of the distal part of the aorta and only improvement in the delineation of the renal arteries were noted when using low concentrations of the contrast media. A loss of signal-to-noise ratio of the aorta and a decrease in arterial visualization were respectively noted with higher concentration of contrast media. In this experimental study, using a transverse three-dimensional TOF TONE MR angiography sequence of renal arteries, in which sequence the saturation effect is minimized, the use of AMI 227 allows only improvement in the delineation of small arteries when using low concentrations of contrast media.

Magnetic resonance imaging evaluation of the ascending aorta after graft-inclusion surgery: comparison between an ultrafast contrast-enhanced MR sequence and conventional cine-MRI.

The aim of this study was to compare the value of two magnitude-based MR sequences, a contrast-enhanced ultrafast MR sequence and a cine MR sequence, for the detection of flow around the graft in the postoperative ascending thoracic aorta. Thirteen patients who underwent ascending aortic surgery for dissection (n = 11) and aneurysm (n = 2) were enrolled. They were referred to MRI for mediastinum enlargement on the chest x-ray or mediastinal symptoms. All patients had replacement of the diseased ascending aorta using a graft-inclusion technique (with wrapping of the native aorta over the graft). Delays between surgery and MRI ranged from 15 days to 8 years (mean: 10 months). All patients were examined using a T1-weighted spin-echo sequence, a magnitude-based cine gradient-echo sequence, and an ultrafast contrast-enhanced MR sequence. MR images of the cine and the contrast-enhanced sequences were retrospectively and independently analyzed by two qualified radiologists for evidence of flow or thrombus around the graft, including perigraft structure and aneurysmal formations. Evidence of flow was detected by both methods in all aneurysmal formations of the ascending aorta located at suture level (n = 6). Evidence of flow in the perigraft structure was found in seven cases by contrast-enhanced MR sequence and in only four cases by cine MR sequence. Contrast-enhanced ultrafast MR sequence could be proposed as a minimally invasive and fast modality for assessing the perigraft structure, in graft-inclusion surgical procedures of the ascending aorta, when noncontrast enhanced MR sequences do not exclude the possibility of flowing blood in this structure.

Thin-section CT detection of emphysema associated with bronchiectasis and correlation with pulmonary function tests.

PURPOSE: To evaluate, on thin-section CT scans, the prevalence of emphysema in patients with bronchiectasis and to correlate the results of thin-section CT scans with the results of pulmonary function tests, in order to question whether there was a particular functional test profile in this group of patients. PATIENTS AND METHODS: This is a retrospective study including 90 patients having both thin-section CT scans and pulmonary function tests for bronchiectasis. A CT scoring system was established for assessing the airway disease by the severity and extent of bronchiectasis and by the extent of emphysema. CT scans were reviewed independently by two reviewers and final interpretation was obtained by consensus. Results of thin-section CT scans were correlated with results of pulmonary function tests, including FEV1 and FEV1/FVC to assess air-way obstruction, total lung capacity and residual volume to assess air trapping, and diffusing capacity for carbon monoxide/alveolar volume (DCO/VA). RESULTS: CT evidence of emphysema, which was noted in 45% of the patients (n = 41), was mainly localized in the same bronchopulmonary segments as bronchiectasis. The presence of emphysema was in relation to the extent and to the severity of bronchiectasis. Only eight patients with CT evidence of emphysema had functional evidence of emphysema (20%). When comparing the group of patients with CT evidence of emphysema with the group of patients with no CT evidence of emphysema, the group of patients with CT evidence of emphysema had significantly higher airflow obstruction and air trapping, had significantly lesser value of diffusing capacity, but with no decreased gas transfer (DCO/VA > 80%). CONCLUSION: Our series suggests that there is a high prevalence of emphysema in patients with bronchiectasis. Emphysema that was not suggested using pulmonary function tests in most of the cases could explain in part the higher airway obstruction observed in the group of patients with CT evidence of emphysema. This study could support the suggestive notion that emphysema, which was mainly localized in bronchiectatic lobes, could be due to the inflammatory airway process.

High-resolution computed tomographic findings associated with histologically diagnosed acute lung rejection in heart-lung transplant recipients.

A group of 32 lung (single lung, [n = 14] and double lung [n = 1]) or heart-lung (n = 17) transplant recipients were studied with serial high-resolution computed tomography (HRCT) scans and transbronchial biopsies from the time of surgery. These investigations were carried out routinely every 2 weeks for the first 2 months, every 2 months for a year, every 4 months in the second year, and on any clinical suspicion of acute lung rejection or infection. A total of 190 transbronchial biopsy specimens and concurrent HRCT scans were obtained. Forty (21%) of the biopsy specimens, showed histologic evidence of lung rejection, 111 (58%) were normal, and 39 (21%) were not conclusive. The more frequent HRCT pattern encountered during an acute rejection episode was the presence of patchy "ground-glass" density areas (65%). This finding was sparsely observed during minimal and mild acute rejection episodes. Using histologic diagnosis as a standard for acute rejection, ground-glass opacities on HRCT had a sensitivity of 65% in detecting lung rejection. Although ground-glass opacities were also intermittently observed during cytomegalovirus pneumonia (14%), this finding had a specificity of 85% for detecting occurrence of an acute lung complication. The detection of ground-glass opacities on lung HRCT after lung transplantation, more particularly after the first month after surgery, can aid the decision of when and where to undertake transbronchial lung biopsy.

Bronchiectasis detected with thin-section CT as a predictor of chronic lung allograft rejection.

PURPOSE: To evaluate bronchiectasis detected with thin-section computed tomography (CT) as a potential early finding of chronic lung allograft rejection. MATERIALS AND METHODS: Forty patients were studied at least 6 months after transplantation. Follow-up CT scans were obtained 6-48 months after transplantation and were retrospectively reviewed for evidence and anatomic extent of bronchiectasis. Irreversible dysfunction of the lung transplant, called the bronchiolitis obliterans syndrome (BOS), was staged according to pulmonary function testing. Pathologic proof of bronchiolitis obliterans was obtained. RESULTS: BOS occurred in 14 (35%) of the 40 patients. When considering bronchiectasis preceding BOS, bronchiectasis was a predictor of chronic rejection with a sensitivity of 14%, a specificity of 77%, a positive predictive value of 25%, and a negative predictive value of 63%. Bronchiectasis appeared concomitantly with BOS in eight (67%) of 12 patients. CONCLUSION: The diagnosis of chronic rejection relies on the degree of impairment of pulmonary function. When the diagnosis is only suspected on the basis of minimal impairment, CT can aid in the diagnosis of rejection by depicting early pulmonary changes.

[Unusual clinical presentation of a thoracic form of a malignant dysembryoma. A case report]. / Présentation clinique inhabituelle d'un dysembryome malin à forme thoracique. A propos d'un cas.

We report here the medical history of a patient diagnosed with teratocarcinoma presenting with a pleural mass without mediastinal involvement as well as typical paraneoplastic hypertrophic osteoarthropathy. This atypical observation is discussed as well as data from the literature on thoracic localisations of extragonadal malignant germ cell tumours.