[The contribution of artificial intelligence (AI) subsequent to the processing of thoracic imaging]. / Apport de l'intelligence artificielle dans le post-traitement de l'imagerie thoracique.

The contribution of artificial intelligence (AI) to medical imaging is currently the object of widespread experimentation. The development of deep learning (DL) methods, particularly convolution neural networks (CNNs), has led to performance gains often superior to those achieved by conventional methods such as machine learning. Radiomics is an approach aimed at extracting quantitative data not accessible to the human eye from images expressing a disease. The data subsequently feed machine learning models and produce diagnostic or prognostic probabilities. As for the multiple applications of AI methods in thoracic imaging, they are undergoing evaluation. Chest radiography is a practically ideal field for the development of DL algorithms able to automatically interpret X-rays. Current algorithms can detect up to 14 different abnormalities present either in isolation or in combination. Chest CT is another area offering numerous AI applications. Various algorithms have been specifically formed and validated for the detection and characterization of pulmonary nodules and pulmonary embolism, as well as segmentation and quantitative analysis of the extent of diffuse lung diseases (emphysema, infectious pneumonias, interstitial lung disease). In addition, the analysis of medical images can be associated with clinical, biological, and functional data (multi-omics analysis), the objective being to construct predictive approaches regarding disease prognosis and response to treatment.

THORACIC INVOLVEMENT IN CONNECTIVE TISSUE DISEASES: RADIOLOGICAL PATTERNS AND FOLLOW-UP.

Connective tissue diseases (CTDs) are a heterogeneous group of idiopathic inflammatory diseases involving various organs. A thoracic involvement is frequent, and chest-CT represents the imaging technique of reference in its assessment. Pulmonary abnormalities related to CTDs are various; although several disease-specific aspects have been described, the two most clinically relevant complications are represented by interstitial lung disease and pulmonary arterial hypertension. The early identification of a thoracic involvement, with the adoption of specific therapies, can significantly change patient's prognosis. The aim of this article is to review the most common typical and atypical CT features of thoracic involvement occurring in CT, especially focusing on interstitial lung disease.

Thoracic involvement in systemic primary vasculitis: radiological patterns and follow-up.

Systemic primary vasculitides are rare idiopathic diseases causing an inflammatory injury to the vessel walls. A pulmonary involvement is frequent, and chest-CT is the imaging technique of reference in its assessment. An extremely wide variety of parenchymal, vascular and airways abnormalities, has been described and diagnosis can be challenging: knowledge of clinical data and a close cooperation with the referring physician is often crucial. The aim of this work is to describe the most common typical and atypical CT features of pulmonary vasculitis and their possible changes over time and therapy, focusing on the differential diagnosis with other inflammatory/infectious or neoplastic diseases.

[Erdheim-Chester disease]. / Maladie d'Erdheim-Chester.

Erdheim-Chester disease is a rare and orphan disease. Despite having been overlooked previously, numerous new cases have been diagnosed more recently. The number of Erdheim-Chester disease cases reported has increased substantially: more than 300 new cases have been published in the past 10 years. This situation is mainly a result of the generally better awareness among pathologists, radiologists, and clinicians of various aspects of this rare disease. The field has been particularly active in the last few years, with evidence of the efficacy of interferon-α, the description of a systemic pro-inflammatory cytokine signature, and most recently, reports of the dramatic efficacy of BRAF inhibition in severe, BRAF(V600E) mutation-associated cases of Erdheim-Chester disease. Also, BRAF mutations have been found in more than half of the patients with Erdheim-Chester disease who were tested. Detailed elucidation of the pathogenesis of the disease is likely to lead to the development of better targeted and more effective therapies.

PHYSIOLOGIC AND QUANTITATIVE COMPUTED TOMOGRAPHY DIFFERENCES BETWEEN CENTRILOBULAR AND PANLOBULAR EMPHYSEMA IN COPD.

BACKGROUND: The purpose was to define the differences between centrilobular (CLE) and panlobular emphysema (PLE) phenotypes in cigarette smokers with COPD by a combined qualitative-quantitative computed tomography (CT) analysis. METHODS: Chest CT scans of 116 cigarette smokers were visually scored by 22 chest radiologists and 29 pulmonologists in a single setting for the predominant emphysema phenotype (e.g. CLE or PLE) and automatically quantified for emphysema{% low attenuation area (LAA) ≤ -950 HU - %LAAinsp-950, gas trapping extent and bronchial metrics{wall area % for segmental (%WAsegm) and subsegmental (%WAsubsegm) bronchi}. These quantitative CT indexes were compared and related to FEV1, FEV1/FVC, and smoking history as stratified for emphysema phenotype. RESULTS: Although more frequent than CLE in GOLD stages 3 and 4 (p = 0.01), PLE was also scored in 38.2% of combined GOLD stages 1 and 2. PLE was positively associated with %LAAinsp-950 (OR = 1.18, 95% CI: 1.12 to 1.27, ß coefficient = 0.17, p = <0.0001) and negatively associated with pack-years of smoking (OR = 0.97, 95% CI: 0.95 to 0.99, ß coefficient = -0.02, p = 0.03). Both %WAsegm and %WAsubsegm were more strongly associated with FEV1% (R2 = 0.6 for both measures, p< 0.001) in CLE as compared to PLE (R2= 0.15, p = 0.02; R2 = 0.26, p< 0.001). CONCLUSIONS: PLE likely represents a more advanced phase of emphysema, which may also occur in earlier COPD stages and show different interplay with airway disease as compared to CLE.

Comparison of various methods for quantitative evaluation of myocardial infarct volume from magnetic resonance delayed enhancement data.

BACKGROUND: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) enables the estimation of myocardial infarct (MI) extent. Nevertheless, manual quantification is time consuming and subjective. We sought to assess MI volume with different quantitative methods in both acute (AMI) and chronic MI (CMI). METHODS: CMR was performed 50 ± 21 h after MI in 52 patients and was repeated 100 ± 21 days later in a subgroup of 34 patients. Then, necrosis volumes were quantified using: 1) manual delineation, 2) automated fuzzy c-means method, and 3) +2 to 6 SD thresholding approaches. Results were compared against peak values of serum Troponin I (TnI), creatine kinase (CK) and left ventricular (LV) functional parameters: LV ejection fraction (LVEF), indexed end-diastolic (EDVi), end-systolic volumes (ESVi) and the number of hypokinetic segments (NbHk). RESULTS: For CMI, quantitative evaluation of infarct size using manual, +2SD, +3 SD and fuzzy c-means provided equivalent results in terms of correlation coefficients for comparisons of MI volumes against LV function parameters (LVEF: r>0.79, p<0.0001; ESVi: r>0.82, p<0.0001, EDVi: r>0.67, p<0.0001, NbHk: r>0.54, p<0.0009). For AMI, +2SD and fuzzy c-means approaches provided higher correlations for comparisons of AMI volumes against biochemical markers (CK: r>0.79, p<0.0001,TnI: r>0.77, p<0.0001) and chronic LV function parameters (LVEF: r>0.82, p<0.0001, NbHk: r>0.59, p<0.0002). CONCLUSIONS: The fuzzy c-means and 2SD methods provided highest correlations with biochemical MI quantification as well as LV function parameters. The fuzzy c-means approach which does not require an arbitrary identification of the remote myocardium is fast and reproducible. It may be clinically useful in the evaluation of patients with MI.

Integrated diagnostics: proceedings from the 9th biennial symposium of the International Society for Strategic Studies in Radiology.

The International Society for Strategic Studies in Radiology held its 9th biennial meeting in August 2011. The focus of the programme was integrated diagnostics and massive computing. Participants discussed the opportunities, challenges, and consequences for the discipline of radiology that will likely arise from the integration of diagnostic technologies. Diagnostic technologies are increasing in scope, including advanced imaging techniques, new molecular imaging agents, and sophisticated point-of-use devices. Advanced information technology (IT), which is increasingly influencing the practice of medicine, will aid clinical communication and the development of "population images" that represent the phenotype of particular diseases, which will aid the development of diagnostic algorithms. Integrated diagnostics offer increased operational efficiency and benefits to patients through quicker and more accurate diagnoses. As physicians with the most expertise in IT, radiologists are well placed to take the lead in introducing IT solutions and cloud computing to promote integrated diagnostics. To achieve this, radiologists must adapt to include quantitative data on biomarkers in their reports. Radiologists must also increase their role as participating physicians, collaborating with other medical specialties, not only to avoid being sidelined by other specialties but also to better prepare as leaders in the selection and sequence of diagnostic procedures. Key Points • New diagnostic technologies are yielding unprecedented amounts of diagnostic information.• Advanced IT/cloud computing will aid integration and analysis of diagnostic data.• Better diagnostic algorithms will lead to faster diagnosis and more rapid treatment.

Focal dependent pleural thickening at MDCT: pleural lesion or functional abnormality?

PURPOSE: To describe the characteristics of reversible focal pleural thickenings (PTs) mimicking real plaques, that firstly suggest asbestos exposure or pleural metastasis; to propose an imaging strategy and propose an explanation for their mechanism of formation. PATIENTS AND METHODS: Retrospective review of data from 19 patients with PTs fitting the description of pleural plaques at chest computed tomography (CT) and presenting modifications (clearance or appearance) of at least one PT at an additional chest examination in prone position. RESULTS: A total of 152 PTs were recorded on the first chest CT examinations with a range of two to 19 pleural opacities per patient. All PTs had a posterior distribution in the lower lobes. On the additional acquisitions, 144 PTs disappeared. Seventeen patients presented complete regression of PTs and two patients presented persistence of eight PTs. CONCLUSION: Additional low dose acquisition in prone position should be performed in all patients presenting with focal PT in a dependent and basal location. This may allow to exclude a pleural plaque in case of asbestos exposure but also a pleural metastasis in oncologic patients. These reversible dependent PTs could be related to physiological focal accumulation of lymphatic fluid in subpleural area.

[Pre-kidney-transplant evaluation of donors and recipients]. / Bilan prétransplantation rénale du receveur et du donneur.

The pretransplant imaging evaluation of recipients is mainly achieved with CT and has two objectives: detection of iliac artery calcifications that may have an impact on the site of the transplant and the type of arterial anastomosis; detection of a primary malignancy that would be a contraindication to transplantation. The pretransplant imaging evaluation of living donors relies on noninvasive techniques. CT angiography and MR angiography both allow the simultaneous evaluation of arteries, excretory tract and renal parenchyma. The goal is to achieve anatomical and functional renal evaluation in order to select the best donor and plan the surgical procedure.

[Bronchial diseases: CT imaging features]. / Sémiologie de l'atteinte bronchique en scanner.

Multidetector row computed tomography (MDCT) is the imaging modality of reference for the diagnosis of bronchiectasis. MDCT may also detect a focal stenosis, a tumor or multiple morphologic abnormalities of the bronchial tree. It may orient the endoscopist towards the abnormal bronchi, and in all cases assess the extent of the bronchial lesions. The CT findings of bronchial abnormalities include anomalies of bronchial division and origin, bronchial stenosis, bronchial wall thickening, lumen dilatation, and mucoid impaction. The main CT features of bronchiectasis are increased bronchoarterial ratio, lack of bronchial tapering, and visibility of peripheral airways. Other bronchial abnormalities include excessive bronchial collapse at expiration, outpouchings and diverticula, dehiscence, fistulas, and calcifications.

[CT imaging features of bronchiolitis]. / Aspect TDM des bronchiolites.

Bronchiolitis may be encountered in numerous clinical circumstances. Previous history of smoking, infections, toxic exposure, immunodeficiency, chronic inflammatory disorders or transplantation must be known. CT findings consist in centrilobular micronodules with sharp or ill borders of various density and/or a mosaic attenuation with expiratory air trapping. Tree-in-bud pattern suggest an inflammatory or infectious bronchiolitis. The associated presence of bronchiectasis and bronchiolectasis must be considered. Imaging-pathologic correlations will be presented for inflammatory bronchiolitis (infectious bronchiolitis, hypersensitivity pneumonitis, respiratory bronchiolitis, follicular bronchiolitis, diffuse panbronchiolitis) and fibrosing bronchiolitis (constrictive bronchiolitis, post-infectious bronchiolitis, toxic fume exposure, transplant-related bronchiolitis).

[Imaging of the postsurgical liver]. / Imagerie du foie opéré

The appearance of the normal postsurgical liver and of potential complications specific to the type of liver resection performed (partial hepatectomy, cyst fenestration, RF ablation) must be well known by radiologists for early detection and treatment of postoperative complications. Early postoperative imaging of the liver aims at detecting vascular, biliary and extrahepatic complications and relies mainly on Doppler US and CT.

[Chest trauma: spectrum of lesions]. / Traumatismes du thorax: lésions élémentaires.

Blunt chest trauma typically occurs as part of polytrauma, usually secondary to motor vehicle accidents, sports related injuries or defenestration in Western Europe. Each chest compartment may be responsible for immediate and/or delayed complications, thus requiring a dedicated systematic and comprehensive analysis. The use of image post-processing is mandatory in order to not overlook a potentially severe injury. The purpose of this paper is to review the technical considerations of multidetector CT, and the imaging features and interpretation method for each chest compartment, in order to generate an adapted report.

Pharmacokinetic evaluation of oral fenofibrate nanosuspensions and SLN in comparison to conventional suspensions of micronized drug.

An increasing number of newly developed drugs show bioavailability problems due to poor water solubility. Formulating the drugs as nanosuspensions may help to overcome these problems by increasing saturation solubility and dissolution velocity. In the present study the bioavailability of the poorly soluble fenofibrate following oral administration was investigated in rats. Four formulations were tested: a nanosuspension type DissoCube(R), one solid lipid nanoparticle (SLN) preparation and two suspensions of micronized fenofibrate as reference formulations, one suspension in sirupus simplex and a second in a solution of hydroxyethy-cellulose in physiological saline. Both colloidal drug delivery systems showed approximately two-fold bioavailability enhancements in terms of rate and extent compared to the reference formulations. No significant differences were found in AUC(0-22 h) as well as in C(max) and t(max) between the two colloidal delivery systems. In conclusion, nanosuspensions may be a suitable delivery system to improve the bioavailability of drugs with low water solubility.

[Computer-aided detection of lung nodules on thin collimation MDCT: impact on radiologists' performance]. / Evaluation de l'impact d'un système CAD sur la performance des radiologues pour la détection des nodules pulmonaires sur des examens scanographiques multicoupes du thorax.

OBJECTIVES: Evaluate the improvement in detecting lung nodules when using multidetector CT (MDCT) computer-assisted diagnosis (CAD). MATERIAL AND METHODS: Three radiologists (R1, R2, R3) with different levels of experience independently interpreted 30 MDCT examinations of the thorax taken for screening purposes, first without and then with CAD. The diagnosis was established by two of the three radiologists interpreting the images together, assisted by the CAD. RESULTS: The consensus reading identified 133 nodules, 61 (46%) of which were 4 mm or larger. The sensitivity values in the detection of nodules before and after using the CAD were 54% and 80% (R1), 38% and 71% (R2), and 70% and 88% (R3), respectively. When considering only the nodules that were 4 mm or larger, the sensitivity values varied before and after using the CAD, from 62% to 95% (R1), from 41% to 84% (R2), and from 74% to 92% (R3). By combining two by two the three radiologists' results obtained without the CAD, the sensitivity values were 65%, 83%, and 77%, respectively, for all the nodules, and 70%, 85%, and 77% for the nodules that were 4 mm or larger. The CAD induced a total of 105 false-positive results, with a mean of 3.5 per examination. CONCLUSION: The lung nodules missed by the radiologist can be detected if the CAD is used as a second reader. The CAD can be at least as beneficial as the use of a second independent reader.

Matrices containing NaCMC and HPMC 2. Swelling and release mechanism study.

The aim of the present study is an investigation of the swelling behaviour of matrix systems containing a mixture of hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) with a model soluble drug to find the correlation between the morphological behaviour and the drug release performance. The swelling study was conducted on tablets containing only the drug and the two polymers mixture (MB) and on reference tablets containing each polymer and the same drug, at three different pHs. MB matrices show a similar swelling trend at pH 4.5 and 6.8, while they have different behaviour in acidic fluid. At pH 1 the gel layer formed by NaCMC is characterized by a rigid structure of a partially chemically crosslinked hydrogel while HPMC and MB matrices form a physical not crosslinked gel. At pH 4.5 and 6.8, all the systems show the typical morphological behaviour of a swellable matrix in which the macromolecular chains in the gel network are held together by weak bondings (physical gel). In these buffers, MB systems maintain a constant drug release rate coupling diffusion and erosion mechanism: the gel and infiltrated layers thicknesses are maintained constant and a zero-order release kinetics can be achieved.

Matrices containing NaCMC and HPMC 1. Dissolution performance characterization.

In this study hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) were used as polymeric carriers to improve controlled release performances of matrix tablets containing a soluble drug. The drug release behaviour of the systems containing these two polymers mixture and each material separately was investigated. To evaluate the effect of the dissolution medium pH, on the drug release performance, release tests were conducted at pH 1, 4.5 and 6.8. In vitro release studies demonstrated that the mixture of the two cellulose derivatives enables a better control of the drug release profiles at pH 4.5 and at 6.8 both in term of rate and mechanism. Texture analysis on the swollen tablets helps to understand drug release kinetic and mechanism. In fact, the results obtained confirm that a gel, which is characterized by high strength and consistence is less susceptible to erosion and chains disentanglement and the drug release mechanism is mainly governed by diffusion. On the contrary, gels, which show a low strength and texture, have low resistance to the fluid erosion action and the release of the active molecule is manly due to polymer relaxation and chains disentanglement moving the drug delivery kinetic towards an erosion/relaxation mechanism.