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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Probing Neuronal Activity using Membrane Interfacial Water
摘要： The use of high-volume quantitative radiomics features extracted from multi-parametric magnetic resonance imaging (MP-MRI) is gaining attraction for the autodetection of prostate tumors, since it provides a plethora of mineable data, which can be used for both detection and prognosis of prostate cancer. While current voxel-resolution radiomics-driven prostate tumor detection approaches utilize quantitative radiomics features associated with individual voxels on an independent basis, the incorporation of additional information regarding the spatial and radiomics feature relationships between voxels has significant potential for achieving a more reliable detection performance. Motivated by this, we present a novel approach for automatic prostate cancer detection using a radiomics-driven conditional random field (RD-CRF) framework. In addition to the high-throughput extraction and utilization of a comprehensive set of voxel-level quantitative radiomics features, the proposed RD-CRF framework leverages inter-voxel spatial and radiomics feature relationships to ensure that the autodetected tumor candidates exhibit interconnected tissue characteristics reflective of cancerous tumors. We evaluated the performance of the proposed framework using clinical prostate MP-MRI data of 20 patients, and the results of RD-CRF framework demonstrated a clear improvement with respect to the state-of-the-art in quantitative radiomics for automatic voxel-resolution prostate cancer detection.
关键词： multi-parametric magnetic resonance imaging (MP-MRI),Automatic prostate cancer detection,radiomics,feature model,conditional random fields (CRF)
更新于2025-09-23 15:21:01
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Stereotactic laser interstitial thermal therapy for brainstem cavernous malformations: two preliminary cases
摘要： Brainstem cavernous malformations (CMs) often have high hemorrhage rates and significant posthemorrhage morbidity. The authors present two cases in which magnetic resonance thermography-guided laser interstitial therapy was used for treatment of pontine CMs after recurrent hemorrhage. Both patients showed significant symptomatic improvement and were hemorrhage-free at 12- and 6-month follow-up, respectively. Each had radiographic evidence of lesion involution on serial follow-up imaging. These early results demonstrate this treatment modality may be technically safe; however, larger case numbers and longer follow-up are needed to demonstrate efficacy.
关键词： Cavernous malformation,Cavernoma,Magnetic resonance imaging,Thermometry,Brainstem,Laser interstitial thermal therapy,Minimally invasive,Stereotactic laser ablation
更新于2025-09-23 15:21:01
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Quantitative assessment of dynamic <sup>18</sup> F-Fluoromethycholine PET and Dynamic Contrast Enhanced MRI in High Risk Prostate Cancer
摘要： Objectives: To describe dynamic 18F-Fluoromethycholine PET (dPET) and dynamic contrast enhancement MR (DCE MR) parameters in localized high-risk prostate cancer (PCa), and determine whether these differ from normal prostate. Furthermore, to determine whether a correlation exists between dPET and DCE MR parameters. Methods: Forty-one consenting patients who underwent prostate DCE MR and dPET were included in this institutionally approved study. Intraprostatic lesions on MR were assigned a PI-RADS v2 score, and focal lesions on PET were documented. All lesions were correlated with pathology. Quantitative and semiquantitative DCE MR and 2-tissue compartmental model dPET parameters were determined and tumor-to-normal gland ratios (T/N) for these parameters were calculated. Finally, dPET and DCE MR correlation was estimated using Spearman correlation coefficients. Results: There were 46 malignant lesions per standard of reference. On dPET, peripheral zone (PZ) tumors had higher K1 (p<0.001), and a T/N ratio ≥2 was significant (p<0.001). On DCE MR, the parameters in, kep, Ktrans and quantitative iAUC were higher for PZ and non-PZ tumors than corresponding normal tissue (p<.001); for PZ tumors, a T/N ratio ≥ 1.5 for Ktrans and pei was significant (p=0.0019 and p=0.0026, respectively). Moderate Spearman correlation (0.40<ρ<0.59) was found between dPET K1 and DCE MR Ktrans and pei. Conclusions: In patients with high-risk PCa, quantitative dPET and DCE-MR parameters in primary tumors differ from normal tissue. Only moderate correlation exists between K1 (dPET) and Ktrans and pei (DCE MR). The incremental value of any of these parameters to PI-RADS v2 warrants further investigation. Advances in knowledge: Unique quantitative and semiquantitative FCH PET/MR parameters in PCa differ from normal gland, and should be further investigated to determine their potential contribution to PI-RADS v2 in the detection of clinically significant PCa.
关键词： Magnetic Resonance Imaging,Positron-Emission Tomography,Prostatic Neoplasms,18f-fluoromethylcholine,Adults
更新于2025-09-23 15:21:01
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Improvement of image quality at CT and MRI using deep learning
摘要： Deep learning has been developed by computer scientists. Here, we discuss techniques for improving the image quality of diagnostic computed tomography and magnetic resonance imaging with the aid of deep learning. We categorize the techniques for improving the image quality as “noise and artifact reduction”, “super resolution” and “image acquisition and reconstruction”. For each category, we present and outline the features of some studies.
关键词： Computed tomography,Image quality improvement,Deep learning,Magnetic resonance imaging
更新于2025-09-23 15:21:01
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Active Maintenance of the Gradient of Refractive Index Is Required to Sustain the Optical Properties of the Lens
摘要： To determine whether the cellular physiology of the lens actively maintains the optical properties of the lens and whether inhibition of lens transport affects overall visual quality. One lens from a pair of bovine lenses was cultured in artificial aqueous humor (AAH), while the other was cultured in either AAH-High-K+ or AAH + 0.1 mM ouabain for 4 hours. Lens pairs or whole enucleated eyes were then imaged in 4.7 Tesla (T) high-field small animal magnet. Lens surface curvatures, T1 measurements of water content, and T2 measurements of water/protein ratios were extracted from cultured lenses, while the geometrical parameters that define the optical pathway were obtained from whole eyes. Gradients of refractive index (GRIN), calculated from T2 measurements, and the extracted geometric parameters were inputted into optical models of the isolated lens and the whole bovine eye. Inhibiting circulating fluxes by inhibiting the Na/K-ATPase with ouabain or depolarization of the lens potential by High K+ caused changes to lens water content, the water/protein ratio (GRIN) and surface geometry that manifested as an increase in optical power and a decrease in negative spherical aberration in cultured lenses. Changes to optical properties of the lens resulted in a myopic shift that impaired vision quality in the optical model of the bovine eye. The cellular physiology of the lens actively maintains its optical properties and inhibiting the Na/K/ATPase induces a myopic shift in vision similar to that observed clinically in patients who go on to develop cataract.
关键词： physiological optics,optical modeling,cataract,gradient of refractive index,lens physiology,magnetic resonance imaging
更新于2025-09-23 15:21:01
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Additive Value of 3T 3D CISS Imaging to Conventional MRI for Assessing the Abnormal Vessels of Spinal Dural Arteriovenous Fistulae
摘要： We investigated the additive value of the 3T 3D constructive interference in steady state (CISS) sequence to conventional MRI for the evaluation of spinal dural arteriovenous fistulae (SDAVF). We included 16 consecutive patients (15 men, 1 woman; age range 42–81 years; mean 64 years) with SDAVF who underwent 3T MRI and digital subtraction angiography (DSA) before treatment. Two neuroradiologists independently evaluated the presence of abnormal vessels on 3D CISS-, T2- and T1-weighted images (T1WI, T2WI), and contrast-enhanced T1WI using a 3-point grading system. Interobserver agreement was assessed by calculating the κ coefficient. The SDAVF site was the cervical region in one patient, the thoracic region in 12 patients, the lumbar region in two, and the sacral region in one. For the visualization of abnormal vessels, the mean score was significantly higher for 3D CISS than the other sequences (P < 0.05). In 12 of 16 cases (75%) both readers made definite positive findings on additional 3D-CISS images. Interobserver agreement was excellent for 3D CISS images (κ = 1.0), good for T1WI (κ = 0.78; 95% confidence interval [CI] 0.54–1.00) and T2WI (κ = 0.74; 95% CI 0.48–1.00) and moderate for contrast-enhanced T1WI (CET1WI) (κ = 0.50; 95% CI 0.21–0.80). Conclusion: For the assessment of abnormal vessels of SDAVF, the 3T 3D CISS sequence adds value to conventional MRI.
关键词： arteriovenous fistulae,spinal dural arteriovenous fistulae,abnormal vessels,constructive interference in steady state,magnetic resonance imaging
更新于2025-09-23 15:21:01
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Prediction of Local Tumor Progression after Radiofrequency Ablation (RFA) of Hepatocellular Carcinoma by Assessment of Ablative Margin Using Pre-RFA MRI and Post-RFA CT Registration
摘要： To evaluate the clinical impact of using registration software for ablative margin assessment on pre-radiofrequency ablation (RFA) magnetic resonance imaging (MRI) and post-RFA computed tomography (CT) compared with the conventional side-by-side MR-CT visual comparison. Materials and Methods: In this Institutional Review Board-approved prospective study, 68 patients with 88 hepatocellulcar carcinomas (HCCs) who had undergone pre-RFA MRI were enrolled. Informed consent was obtained from all patients. Pre-RFA MRI and post-RFA CT images were analyzed to evaluate the presence of a sufficient safety margin (≥ 3 mm) in two separate sessions using either side-by-side visual comparison or non-rigid registration software. Patients with an insufficient ablative margin on either one or both methods underwent additional treatment depending on the technical feasibility and patient’s condition. Then, ablative margins were re-assessed using both methods. Local tumor progression (LTP) rates were compared between the sufficient and insufficient margin groups in each method. Results: The two methods showed 14.8% (13/88) discordance in estimating sufficient ablative margins. On registration software-assisted inspection, patients with insufficient ablative margins showed a significantly higher 5-year LTP rate than those with sufficient ablative margins (66.7% vs. 27.0%, p = 0.004). However, classification by visual inspection alone did not reveal a significant difference in 5-year LTP between the two groups (28.6% vs. 30.5%, p = 0.79). Conclusion: Registration software provided better ablative margin assessment than did visual inspection in patients with HCCs who had undergone pre-RFA MRI and post-RFA CT for prediction of LTP after RFA and may provide more precise risk stratification of those who are treated with RFA.
关键词： Fusion,Margin,Magnetic resonance imaging,Local tumor progression,Radiofrequency ablation
更新于2025-09-23 15:21:01
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Quantitative imaging techniques for the assessment of osteoporosis and sarcopenia
摘要： Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk.
关键词： sarcopenia,Osteoporosis,photon,magnetic resonance imaging (MRI),absorptiometry,multidetector computed tomography (CT)
更新于2025-09-23 15:21:01
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Early Detection of Cerebral Infarction With Middle Cerebral Artery Occlusion With Functional Near-Infrared Spectroscopy: A Pilot Study
摘要： Background: NIRSIT, a functional near-infrared spectroscopy (fNIRS) device with 204 channels, can measure oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) in non-pulsatile blood ?ow non-invasively using the absorption difference between HbO2 and HbR at a wavelength of 700–1,000 nm and can display the perfusion status in real time. Objective: We applied NIRSIT to patients with stroke to evaluate the usefulness of NIRSIT as an fNIRS device for the early detection of stroke. Methods: We performed a prospective pilot study in an emergency department (ED). Adult patients who had suspected symptoms and signs of stroke within 12 h of the ?rst abnormal time and who underwent intravenous thrombolysis (IVT) or intra-arterial thrombectomy with acute middle cerebral artery (MCA) or internal carotid artery (ICA) infarction were enrolled. NIRSIT was applied to the patients before the imaging study, and the perfusion status of the brain was displayed in real time at the bedside. We compared the NIRSIT results with the mean transit time (MTT) map from perfusion computed tomography (PCT) and the time-to-peak (TTP) map from perfusion-weighted magnetic resonance imaging (PWI). Results: Six male and three female patients were enrolled, and the median age was 74 years. The most common symptom was unilateral extremity weakness (77.8%), followed by dysarthria (33.3%) and aphasia (11.1%). The median National Institutes of Health Stroke Scale (NIHSS) score was 17. All cases of MCA infarction showed different cerebral oxygen saturation values between bilateral lobes of the brain in fNIRS imaging, and these values matched the PCT and PWI results. Conclusions: The brain hemisphere with low oxygen saturation on fNIRS showed hypoperfusion on PCT or PWI. The fNIRS device could be useful in assessing the perfusion status of the brain and detecting MCA or ICA infarction in real time at the bedside.
关键词： middle cerebral artery,magnetic resonance imaging,computed tomography,perfusion,cerebral infarction
更新于2025-09-23 15:21:01
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MedGA: A novel evolutionary method for image enhancement in medical imaging systems
摘要： Medical imaging systems often require the application of image enhancement techniques to help physicians in anomaly/abnormality detection and diagnosis, as well as to improve the quality of images that undergo automated image processing. In this work we introduce MedGA, a novel image enhancement method based on Genetic Algorithms that is able to improve the appearance and the visual quality of images characterized by a bimodal gray level intensity histogram, by strengthening their two underlying sub-distributions. MedGA can be exploited as a pre-processing step for the enhancement of images with a nearly bimodal histogram distribution, to improve the results achieved by downstream image processing techniques. As a case study, we use MedGA as a clinical expert system for contrast-enhanced Magnetic Resonance image analysis, considering Magnetic Resonance guided Focused Ultrasound Surgery for uterine fibroids. The performances of MedGA are quantitatively evaluated by means of various image enhancement metrics, and compared against the conventional state-of-the-art image enhancement techniques, namely, histogram equalization, bi-histogram equalization, encoding and decoding Gamma transformations, and sigmoid transformations. We show that MedGA considerably outperforms the other approaches in terms of signal and perceived image quality, while preserving the input mean brightness. MedGA may have a significant impact in real healthcare environments, representing an intelligent solution for Clinical Decision Support Systems in radiology practice for image enhancement, to visually assist physicians during their interactive decision-making tasks, as well as for the improvement of downstream automated processing pipelines in clinically useful measurements.
关键词： Medical imaging systems,Genetic Algorithms,Uterine fibroids,Magnetic resonance imaging,Bimodal image histogram,Image enhancement
更新于2025-09-23 15:21:01