Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

Objectives: The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Methods: Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. Results: The radiation dose of ULD-CT was 0.16 ± 0.006mSv compared with 11.2 ± 2.7mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Conclusion: Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. Key Points : • Radiation dose is a key concern with the increased use of thoracic CT • Ultra-low-dose chest CT approximates the radiation dose of conventional chest radiography • Ultra-low-dose chest CT can be of diagnostic quality • Solid pulmonary nodules are clearly depicted on ultra-low-dose chest C

Solid Spherical Energy (SSE) CNNs for Efficient 3D Medical Image Analysis

Invariance to local rotation, to differentiate from the global rotation of images and objects, is required in various texture analysis problems. It has led to several breakthrough methods such as local binary patterns, maximum response and steerable filterbanks. In particular, textures in medical images often exhibit local structures at arbitrary orientations. Locally Rotation Invariant (LRI) Convolutional Neural Networks (CNN) were recently proposed using 3D steerable filters to combine LRI with Directional Sensitivity (DS). The steerability avoids the expensive cost of convolutions with rotated kernels and comes with a parametric representation that results in a drastic reduction of the number of trainable parameters. Yet, the potential bottleneck (memory and computation) of this approach lies in the necessity to recombine responses for a set of predefined discretized orientations. In this paper, we propose to calculate invariants from the responses to the set of spherical harmonics projected onto 3D kernels in the form of a lightweight Solid Spherical Energy (SSE) CNN. It offers a compromise between the high kernel specificity of the LRI-CNN and a low memory/operations requirement. The computational gain is evaluated on 3D synthetic and pulmonary nodule classification experiments. The performance of the proposed approach is compared with steerable LRI-CNNs and standard 3D CNNs, showing competitive results with the state of the art

Superparamagnetic nanoparticles – a tool for early diagnostics

Nanoparticles show several interesting new physical and biological properties and therefore play an increasing role in pharmaceutics and medicine. For more than 30 years this research field has been developing slowly but steadily from physical and biological interest (bench) to applications in clinics (bedside). However, many of these particles for biomedical applications are still in the pre-clinical or clinical phase. Combined with drugs or genes these nanoparticles may change the viability of or the transcription processes in cells, which make them interesting for the pharmaceutical industry, cell biology and diagnostics. Because most of the application of superparamagnetic nanoparticles as therapeutic tool, like non-viral vector, drug delivery, are still far from clinical use, this review will concentrate on superparamagnetic nanoparticles as versatile agent for early diagnosis, including the use of such particles as contrast agent for MR imaging and as vehicle for the detection of biomarkers

Experimental noninferiority trial of synthetic small-caliber biodegradable versus stable vascular grafts

ObjectiveLong-term evolution of polycaprolactone vascular prostheses has been investigated recently. The goal of this study was to evidence a noninferiority of such grafts compared with expanded polytetrafluoroethylene (ePTFE) implants in an aortic replacement model in the rat.MethodsFourteen anesthetized Sprague-Dawley rats received an infrarenal aortic graft (biodegradable, n = 8; expanded polytetrafluoroethylene, n = 6) replacement (end to end; inner diameter, 2 mm). Biodegradable grafts (polycaprolactone) were produced by random micro-/nanofiber electrospinning. After a median survival of 16.5 months, in vivo ultrasonography and angiography as well as postexplantation microcomputed tomography, histomorphometry, immunohistochemistry, and scanning electron microscopy were performed.ResultsPatency was 100% for polycaprolactone and 67% for ePTFE. No aneurysmal dilatation or stenoses were found in either group. Compliance was significantly higher for polycaprolactone compared with ePTFE (8.2 ± 1.0%/100 mm Hg vs 5.7 ± 0.7%/100 mm Hg; P < .01), but markedly reduced compared with adjacent native aortas and the control group. Histologically, low cellular in-growth was found in ePTFE whereas polycaprolactone showed significantly greater homogenous cellularity, producing an autologous extracellular matrix (10.8% ± 4.0% vs 32.1% ± 9.2%, P < .0001). Morphometry showed 100% neo-endothelialization for both grafts with a totally confluent endothelial coverage for polycaprolactone grafts by scanning electron microscope. More intimal hyperplasia was found in ePTFE compared with polycaprolactone grafts. Calcification was higher in ePTFE than in polycaprolactone grafts (15.8% vs 7.0%, P = .04) and was absent in controls.ConclusionsOutcomes of synthetic biodegradable nanofiber polycaprolactone grafts are not inferior compared with the clinically used expanded polytetrafluoroethylene grafts after long-term implantation in the rat aorta. Moreover, these implants show better patency, compliance, endothelialization, and cell in-growth, and less intimal hyperplasia and calcification than their counterparts

Urinary stone detection and characterisation with dual-energy CT urography after furosemide intravenous injection: preliminary results

Objectives: To investigate the added advantage of IV furosemide injection and the subsequent urine dilution in the detection of urinary calculi in the excretory phase of dual-source dual-energy (DE) computed tomography (CT) urography, and to investigate the feasibility of characterising the calculi through diluted urine. Methods: Twenty-three urinary calculi were detected in 116 patients who underwent DECT urography for macroscopic haematuria with a split bolus two- or three-acquisition protocol, including a true unenhanced series and at least a mixed nephrographic excretory phase. Virtual unenhanced images were reconstructed from contrast-enhanced DE data. Calculi were recorded on all series and characterised based on their X-ray absorption characteristics at 100kVp and 140kVp in both true unenhanced and nephrographic excretory phase series. Results: All calculi with a diameter more than 2mm were detected in the virtual unenhanced phase and in the nephrographic excretory phase. Thirteen of these calculi could be characterised in the true unenhanced phase and in the mixed nephrographic excretory phase. The results were strictly identical for both phases, six of them being recognised as non-uric acid calculi and seven as uric acid calculi. Conclusions: Mixed nephrographic excretory phase DECT after furosemide administration allows both detection and characterisation of clinically significant calculi, through the diluted urine. Key points: • Urinary tract stones can be detected on excretory phase through diluted urine. • Urinary tract stone characterisation with dual-energy CT (DECT) is possible through diluted urine. • A dual energy split-bolus CT urography simultaneously enables urinary stone detection and characterisation

Gastrointestinal relapse of multiple myeloma and sustained response to lenalidomide: a case report

<p>Abstract</p> <p>Introduction</p> <p>Gastrointestinal relapse in patients with multiple myeloma is very rare and, when reported, always associated with a poor prognosis.</p> <p>Case presentation</p> <p>We describe the case of a 71-year-old Caucasian man who presented with life-threatening hematemesis and melena due to a digestive relapse of his multiple myeloma. Despite the active hemorrhage, we initiated a third-line treatment with lenalidomide. The response was spectacular and long-lasting.</p> <p>Conclusions</p> <p>Clinicians must consider digestive tract involvement in myeloma patients presenting with a gastrointestinal hemorrhage. Furthermore, myeloma patients do benefit from novel oral drugs, even when they are critically ill.</p

Mir-21 Suppression Promotes Mouse Hepatocarcinogenesis.

The microRNA 21 (miR-21) is upregulated in almost all known human cancers and is considered a highly potent oncogene and potential therapeutic target for cancer treatment. In the liver, miR-21 was reported to promote hepatic steatosis and inflammation, but whether miR-21 also drives hepatocarcinogenesis remains poorly investigated in vivo. Here we show using both carcinogen (Diethylnitrosamine, DEN) or genetically (PTEN deficiency)-induced mouse models of hepatocellular carcinoma (HCC), total or hepatocyte-specific genetic deletion of this microRNA fosters HCC development-contrasting the expected oncogenic role of miR-21. Gene and protein expression analyses of mouse liver tissues further indicate that total or hepatocyte-specific miR-21 deficiency is associated with an increased expression of oncogenes such as Cdc25a, subtle deregulations of the MAPK, HiPPO, and STAT3 signaling pathways, as well as alterations of the inflammatory/immune anti-tumoral responses in the liver. Together, our data show that miR-21 deficiency promotes a pro-tumoral microenvironment, which over time fosters HCC development via pleiotropic and complex mechanisms. These results question the current dogma of miR-21 being a potent oncomiR in the liver and call for cautiousness when considering miR-21 inhibition for therapeutic purposes in HCC

Genetic Ablation of MiR-22 Fosters Diet-Induced Obesity and NAFLD Development

miR-22 is one of the most abundant miRNAs in the liver and alterations of its hepatic expression have been associated with the development of hepatic steatosis and insulin resistance, as well as cancer. However, the pathophysiological roles of miR-22-3p in the deregulated hepatic metabolism with obesity and cancer remains poorly characterized. Herein, we observed that alterations of hepatic miR-22-3p expression with non-alcoholic fatty liver disease (NAFLD) in the context of obesity are not consistent in various human cohorts and animal models in contrast to the well-characterized miR-22-3p downregulation observed in hepatic cancers. To unravel the role of miR-22 in obesity-associated NAFLD, we generated constitutive Mir22 knockout (miR-22KO) mice, which were subsequently rendered obese by feeding with fat-enriched diet. Functional NAFLD- and obesity-associated metabolic parameters were then analyzed. Insights about the role of miR-22 in NAFLD associated with obesity were further obtained through an unbiased proteomic analysis of miR-22KO livers from obese mice. Metabolic processes governed by miR-22 were finally investigated in hepatic transformed cancer cells. Deletion of Mir22 was asymptomatic when mice were bred under standard conditions, except for an onset of glucose intolerance. However, when challenged with a high fat-containing diet, Mir22 deficiency dramatically exacerbated fat mass gain, hepatomegaly, and liver steatosis in mice. Analyses of explanted white adipose tissue revealed increased lipid synthesis, whereas mass spectrometry analysis of the liver proteome indicated that Mir22 deletion promotes hepatic upregulation of key enzymes in glycolysis and lipid uptake. Surprisingly, expression of miR-22-3p in Huh7 hepatic cancer cells triggers, in contrast to our in vivo observations, a clear induction of a Warburg effect with an increased glycolysis and an inhibited mitochondrial respiration. Together, our study indicates that miR-22-3p is a master regulator of the lipid and glucose metabolism with differential effects in specific organs and in transformed hepatic cancer cells, as compared to non-tumoral tissue