Results for “Biomedical diagnostics” — Page 17

NASA NTRS2002

Advances in space technology: the NSBRI Technology Development Team

As evidenced from Mir and other long-duration space missions, the space environment can cause significant alterations in the human physiology that could prove dangerous for astronauts. The NASA programme to develop countermeasures for these deleterious human health effects is being carried out by the National Space Biomedical Research Institute (NSBRI). The NSBRI has 12 research teams, ten of which are primarily physiology based, one addresses on-board medical care, and the twelfth focuses on technology development in support of the other research teams. This Technology Development (TD) Team initially supported four instrumentation developments: (1) an advanced, multiple projection, dual energy X ray absorptiometry (AMPDXA) scanning system: (2) a portable neutron spectrometer; (3) a miniature time-of-flight mass spectrometer: and (4) a cardiovascular identification system. Technical highlights of the original projects are presented along with an introduction to the five new TD Team projects being funded by the NSBRI.

Non-NASA Center↗

DOE OSTI2017

3D-Printed pHEMA Materials for Topographical and Biochemical Modulation of Dorsal Root Ganglion Cell Response

Understanding and controlling the interactions occurring between cells and engineered materials are central challenges toward progress in the development of biomedical devices. In this work, we describe materials for direct ink writing (DIW), an extrusion-based type of 3D printing, that embed a custom synthetic protein (RGD-PDL) within the microfilaments of 3D-hydrogel scaffolds to modify these interactions and differentially direct tissue-level organization of complex cell populations in vitro. The RGD-PDL is synthesized by modifying poly-d-lysine (PDL) to varying extents with peptides containing the integrin-binding motif Arg-Gly-Asp (RGD). Compositional gradients of the RGD-PDL presented by both patterned and thin-film poly(2-hydroxyethyl) methacrylate (pHEMA) substrates allow the patterning of cell-growth compliance in a grayscale form. The surface chemistry-dependent guidance of cell growth on the RGD-PDL-modified pHEMA materials is demonstrated using a model NIH-3T3 fibroblast cell line. The formation of a more complex cellular system—organotypic primary murine dorsal root ganglion (DRG)—in culture is also achieved on these scaffolds, where distinctive forms of cell growth and migration guidance are seen depending on their RGD-PDL content and topography. In conclusion, this experimental platform for the study of physicochemical factors on the formation and the reorganization of organotypic cultures offers useful capabilities for studies in tissue engineering, regenerative medicine, and diagnostics.

36 MATERIALS SCIENCE↗

DOE OSTI2016

WE-DE-206-00: MRI Physics

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation. This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner. Learning Objectives: Understand the origin of the MR signal and contrast from the spin physics level. Understand the main hardware components of a MRI scanner and their purposes Understand steps for MR image formation including spatial encoding and image reconstruction Understand the main kinds of MR pulse sequences and their characteristics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2019

Imaging Approaches for Coronary Artery Anomalies: Purpose and Techniques

Purpose of Review: Comprehensive discussion of alternative techniques in imaging coronary artery anomalies (CAAs) in different diagnostic scenarios. Recent Findings: At primary screening, intramural course essentially correlates with stenosis and clinical repercussion in some types of CAAs. Potential clinical aims in imaging patients with CAAs may be primary screening, severity evaluation, preoperative planning, and postoperative follow-up. Appropriate techniques are echocardiography, magnetic resonance imaging, computed tomography angiography, and intravascular ultrasound (IVUS). Rarely, IVUS may be needed in patients with potentially serious CAAs and has unique advantages and limitations. IVUS data are essential for in-depth knowledge of mechanisms of coronary dysfunction (exercise-related dynamic stenosis of variable severity) and for indicating interventional treatment. Summary: In adolescents or adults, intramural course of an anomalous coronary artery is the only important feature accompanied by stenosis of potential severity and is especially relevant in patients with a high-risk status (elite sport athletes, military recruits).

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2013

The Role of Interventional Radiology in the Diagnosis and Management of Male Impotence

Erectile dysfunction (ED) is defined as the persistent inability to reach or maintain penile rigidity enough for sexual satisfaction. Nearly 30% of the men between ages 40 and 70 years are affected by ED. A variety of pathologies, including neurological, psychological, or endocrine disorders and drug side effects, may incite ED. A commonly identified cause of ED is vascular disease. Initial diagnostic workup includes a detailed physical examination and laboratory tests. Whilst duplex ultrasound is considered the first-line diagnostic modality, intra-arterial digital subtraction angiography is still considered the 'gold standard' for the diagnosis of arteriogenic impotence. Percutaneous endovascular treatment may be offered in patients with vasculogenic ED that has failed to respond to oral medical therapy as an alternative to penile prosthesis or open surgical repair. In arteriogenic ED balloon angioplasty of the aorto-iliac axis, and in veno-occlusive ED, percutaneous venous ablation using various embolization materials has been reported to be safe and to improve sexual performance. Recently, the ZEN study investigated the safety and feasibility of drug-eluting stents for the treatment of arteriogenic ED attributed to internal pudendal artery stenosis with promising preliminary results. This manuscript highlights the role of interventional radiology in the diagnosis and minimally invasive treatment of male impotence.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2016

WE-DE-206-01: MRI Signal in Biological Tissues - Proton, Spin, T1, T2, T2*

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation. This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner. Learning Objectives: Understand the origin of the MR signal and contrast from the spin physics level. Understand the main hardware components of a MRI scanner and their purposes Understand steps for MR image formation including spatial encoding and image reconstruction Understand the main kinds of MR pulse sequences and their characteristics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

WE-DE-206-02: MRI Hardware - Magnet, Gradient, RF Coils

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation. This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner. Learning Objectives: Understand the origin of the MR signal and contrast from the spin physics level. Understand the main hardware components of a MRI scanner and their purposes Understand steps for MR image formation including spatial encoding and image reconstruction Understand the main kinds of MR pulse sequences and their characteristics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

WE-DE-206-03: MRI Image Formation - Slice Selection, Phase Encoding, Frequency Encoding, K-Space, SNR

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation. This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner. Learning Objectives: Understand the origin of the MR signal and contrast from the spin physics level. Understand the main hardware components of a MRI scanner and their purposes Understand steps for MR image formation including spatial encoding and image reconstruction Understand the main kinds of MR pulse sequences and their characteristics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

WE-DE-206-04: MRI Pulse Sequences - Spin Echo, Gradient Echo, EPI, Non-Cartesia

Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation. This lecture will give an overview of the spin physics, imaging principle of MRI, the hardware of the MRI scanner, and various pulse sequences and their applications. It aims to provide a conceptual foundation to understand the image formation process of a clinical MRI scanner. Learning Objectives: Understand the origin of the MR signal and contrast from the spin physics level. Understand the main hardware components of a MRI scanner and their purposes Understand steps for MR image formation including spatial encoding and image reconstruction Understand the main kinds of MR pulse sequences and their characteristics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-I-37: How Fat Distribution and Table Height Affect Estimates of Patient Size in CT Scanning: A Phantom Study

Purpose: Localizer projection radiographs acquired prior to CT scans are used to estimate patient size, affecting the function of Automatic Tube Current Modulation (ATCM) and hence CTDIvol and SSDE. Due to geometric effects, the projected patient size varies with scanner table height and with the orientation of the localizer (AP versus PA). This study sought to determine if patient size estimates made from localizer scans is affected by variations in fat distribution, specifically when the widest part of the patient is not at the geometric center of the patient. Methods: Lipid gel bolus material was wrapped around an anthropomorphic phantom to simulate two different body mass distributions. The first represented a patient with fairly rigid fat and had a generally oval shape. The second was bell-shaped, representing corpulent patients more susceptible to gravity’s lustful tug. Each phantom configuration was imaged using an AP localizer and then a PA localizer. This was repeated at various scanner table heights. The width of the phantom was measured from the localizer and diagnostic images using in-house software. Results: 1) The projected phantom width varied up to 39% as table height changed.2) At some table heights, the width of the phantom, designed to represent larger patients, exceeded the localizer field of view, resulting in an underestimation of the phantom width.3) The oval-shaped phantom approached a normalized phantom width of 1 at a table height several centimeters lower (AP localizer) or higher (PA localizer) than did the bell-shaped phantom. Conclusion: Accurate estimation of patient size from localizer scans is dependent on patient positioning with respect to scanner isocenter and is limited in large patients. Further, patient size is more accurately measured on projection images if the widest part of the patient, rather than the geometric center of the patient, is positioned at scanner isocenter.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2019

Uterine carcinosarcoma: a primer for radiologists

Objective: To provide a modern overview for radiologists of the unique radiological, pathological, and clinical features of uterine carcinosarcoma (UCS). Results: UCS is a unique gynecological malignancy that continues to present diagnostic and therapeutic challenges to the field of oncology. The classification and clinical understanding of this malignancy have evolved in recent years, yielding a modern conceptualization of a neoplastic entity that has been well studied but incompletely understood. As UCS causes a significant proportion of deaths secondary to uterine cancer, developing a familiarity with the imaging and clinical features of this entity is critical. In addition to summarizing the modern understanding of this tumor variant, an overview of the common imaging features of UCS will be presented. The role of radiological staging, imaging findings on presentation and follow-up imaging, and modern treatment paradigms will be discussed. Lastly, the current treatment paradigms and surveillance recommendations for UCS will be summarized. Conclusion: Knowledge of the modern understanding of uterine carcinosarcoma, including its relevant imaging and clinical features, is critical for radiologists.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2019

Non-invasive Risk Stratification for Coronary Artery Disease: Is It Time for Subclassifications?

Purpose of Review: Coronary artery disease (CAD) is the leading contributor to cardiovascular disease; it is the most prevalent non-communicable disease globally and has high morbidity, mortality and health care cost. Risk stratification is defined as prevention or containment of disease prior to it occurring or progressing, and non-invasive surrogates include history, examination, biomarkers and non-invasive imaging. This review aims to highlight advancement in current diagnostic strategies and explores gaps for CAD secondary to atherosclerosis and non-obstructive vascular diseases. Recent Findings: Cardiac risk scores have largely proven inadequate in risk stratifying heterogeneous patient populations. Greater emphasis should also be provided to posttest risk stratification. Non-invasive imaging with MRI is the most accurate but least cost efficacious presently due to availability and expertise. Echocardiography and nuclear imaging have good accuracy, but radiation limits the latter. Novel echocardiographic technologies may increase its appeal. Cardiac CT angiography is increasingly promising. Summary: Non-invasive and minimally invasive imaging has significantly influenced the cost-efficacy trajectory of coronary artery disease diagnosis and management. Recent studies suggest that future guidelines will incorporate more subclassifications from the findings of these novel technologies and for more diverse patient demographics.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2016

SU-D-209-03: Radiation Dose Reduction Using Real-Time Image Processing in Interventional Radiology

Purpose: To characterize changes in radiation dose after introducing a new real-time image processing technology in interventional radiology systems. Methods: Interventional radiology (IR) procedures are increasingly complex, at times requiring substantial time and radiation dose. The risk of inducing tissue reactions as well as long-term stochastic effects such as radiation-induced cancer is not trivial. To reduce this risk, IR systems are increasingly equipped with dose reduction technologies.Recently, ClarityIQ (Philips Healthcare) technology was installed in our existing neuroradiology IR (NIR) and vascular IR (VIR) suites respectively. ClarityIQ includes real-time image processing that reduces noise/artifacts, enhances images, and sharpens edges while also reducing radiation dose rates. We reviewed 412 NIR (175 pre- and 237 post-ClarityIQ) procedures and 329 VIR (156 preand 173 post-ClarityIQ) procedures performed at our institution pre- and post-ClarityIQ implementation. NIR procedures were primarily classified as interventional or diagnostic. VIR procedures included drain port, drain placement, tube change, mesenteric, and implanted venous procedures. Air Kerma (AK in units of mGy) was documented for all the cases using a commercial radiation exposure management system. Results: When considering all NIR procedures, median AK decreased from 1194 mGy to 561 mGy. When considering all VIR procedures, median AK decreased from 49 to 14 mGy. Both NIR and VIR exhibited a decrease in AK exceeding 50% after ClarityIQ implementation, a statistically significant (p<0.05) difference. Of the 5 most common VIR procedures, all median AK values decreased, but significance (p<0.05) was only reached in venous access (N=53), angio mesenteric (N=41), and drain placement procedures (N=31). Conclusion: ClarityIQ can reduce dose significantly for both NIR and VIR procedures. Image quality was not assessed in conjunction with the dose reduction.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

Patterns of Recurrence in Electively Irradiated Lymph Node Regions After Definitive Accelerated Intensity Modulated Radiation Therapy for Head and Neck Squamous Cell Carcinoma

Purpose: To provide a comprehensive risk assessment on the patterns of recurrence in electively irradiated lymph node regions after definitive radiation therapy for head and neck cancer. Methods and Materials: Two hundred sixty-four patients with stage cT2-4N0-2M0 squamous cell carcinoma of the oropharynx, larynx, or hypopharynx treated with accelerated intensity modulated radiation therapy between 2008 and 2012 were included. On the radiation therapy planning computed tomography (CT) scans from all patients, 1166 lymph nodes (short-axis diameter ≥5 mm) localized in the elective volume were identified and delineated. The exact sites of regional recurrences were reconstructed and projected on the initial radiation therapy planning CT scan by performing coregistration with diagnostic imaging of the recurrence. Results: The actuarial rate of recurrence in electively irradiated lymph node regions at 2 years was 5.1% (95% confidence interval 2.4%-7.8%). Volumetric analysis showed an increased risk of recurrence with increasing nodal volume. Receiver operating characteristic analysis demonstrated that the summed long- and short-axis diameter is a good alternative for laborious volume calculations, using ≥17 mm as cut-off (hazard ratio 17.8; 95% confidence interval 5.7-55.1; P<.001). Conclusions: An important risk factor was identified that can help clinicians in the pretreatment risk assessment of borderline-sized lymph nodes. Not overtly pathologic nodes with a summed diameter ≥17 mm may require a higher than elective radiation therapy dose. For low-risk elective regions (all nodes <17 mm), the safety of dose de-escalation below the traditional 45 to 50 Gy should be investigated.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2016

TH-AB-207A-04: Assessment of Patients’ Cumulative Effective Dose From CT Examinations

Purpose: The Joint Commission requires institutions to consider patient’s age and recent imaging exams when deciding on the most appropriate type of imaging exam. Additionally, knowing patient’s imaging history can help prevent duplicate scans. Radiation dose management software affords new opportunities to identify and utilize patients with high cumulative doses as one proxy for subsequent review of imaging history and opportunities in avoiding redundant exams. Methods: Using dose management software (Radimetrics, Bayer Healthcare) a total of 72073 CT examinations performed from Jan 2015 to Jan 2016 were examined to categorize patients with a cumulative effective dose of 100 mSv and above. This threshold was selected based on epidemiological studies on populations exposed to radiation, which demonstrate a statistical increase of cancer risk at doses above 100 mSv. Histories of patients with highest cumulative dose and highest number of exams were further investigated by a Radiologist for appropriateness of recurrent studies and potential opportunities for reduction. Results: Out of 34762 patients, 927 (2.7%) were identified with a cumulative dose of 100 mSv and above. The highest cumulative dose (842 mSv) belonged to an oncology patient who underwent 2 diagnostic exams and 9 interventional ablative CT guided procedures. The patient with highest number of exams (56 counts) and cumulative dose of 170 mSv was a 17 year old trauma patient. An imaging history review of these two patients did not suggest any superfluous scans. Conclusion: Our limited pilot study suggests that recurrent CT exams for patients with oncologic or severe trauma history may be warranted and appropriate. As a result, for future studies we will be focusing on high dose patient cohorts not associated with oncology or severe trauma. Additionally, the review process itself has suggested areas for potential improvement in patient care, including improved documentation and Radiologist involvement in patient management. Dr. McNitt-Gray’s disclosures: Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical Systems; Consultant, Samsung Electronics.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2019

A need to reduce premature CV mortality in the developing world: How could appropriate use of non-invasive imaging help?

We discuss premature deaths due to coronary heart disease (CHD) in developing countries and the importance of a comprehensive approach, involving clinical judgement, prevention, appropriate use of technology to diagnose and guide CHD treatment. Healthcare policies and levels of knowledge vary tremendously resulting heterogeneous utilization of diagnostic strategies and treatments worldwide. Many countries with high mortality have low utilization of non-invasive cardiac imaging. Appropriate use coupled with guideline-based management could help to improve care in the developing world and potentially result in better life expectancy already experienced by most high-income countries. In a scenario of increasing costs, a rational utilization of resources is imperative for all nations. A stepwise approach to suspected CHD is necessary, starting from good judgement, adding tests only as needed, preferably filtering patients who might benefit from advanced imaging. In stable patients, non-invasive tests should be used as filters to invasive procedure, preventing stable patients from undergoing revascularizations of questionable benefit. In this article, we review the relative role of exercise testing, myocardial perfusion imaging, and coronary computed tomography angiography to evaluate CHD and how these can be utilized as ways to help guide management that could impact premature mortality in developing nations.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2019

Imaging post-stereotactic body radiation therapy responses for hepatocellular carcinoma: typical imaging patterns and pitfalls

Stereotactic body radiation therapy (SBRT) has increased utility in the management of hepatocellular carcinoma (HCC) ranging from local therapy in early-stage HCC not suitable for other focal therapies to end-stage HCC. As the indications for the use of SBRT in HCC expand, diagnostic imaging is being increasingly used to assess response to treatment. The imaging features of tumor response do not parallel those of other focal therapies such as radiofrequency ablation or trans-arterial chemoembolization that immediately devascularize the tumor. The tumor response to SBRT on imaging takes much longer and often shows gradual changes including the reduction of enhancement and size over several months. It is essential to recognize the typical imaging patterns of response, as well as the appearance of focal liver reaction in the non-target liver that can confound image interpretation. The timing of treatment response assessment imaging is fundamental to minimize the potential for false negative response. The purpose of this article is to review the variable post-SBRT imaging features of HCC and adjacent liver parenchyma and discuss the potential pitfalls of imaging evaluation after SBRT for HCC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2015

SU-E-J-218: Novel Validation Paradigm of MRI to CT Deformation of Prostate

Purpose: Deformable registration algorithms are inherently difficult to characterize in the multi-modality setting due to a significant differences in the characteristics of the different modalities (CT and MRI) as well as tissue deformations. We present a unique paradigm where this is overcome by utilizing a planning-MRI acquired within an hour of the planning-CT serving as a surrogate for quantifying MRI to CT deformation by eliminating the issues of multi-modality comparisons. Methods: For nine subjects, T2 fast-spin-echo images were acquired at two different time points, the first several weeks prior to planning (diagnostic-MRI) and the second on the same day as the planning-CT (planning-MRI). Significant effort in patient positioning and bowel/bladder preparation was undertaken to minimize distortion of the prostate in all datasets. The diagnostic-MRI was rigidly and deformably aligned to the planning-CT utilizing a commercially available deformable registration algorithm synthesized from local registrations. Additionally, the quality of rigid alignment was ranked by an imaging physicist. The distances between corresponding anatomical landmarks on rigid and deformed registrations (diagnostic-MR to planning-CT) were evaluated. Results: It was discovered that in cases where the rigid registration was of acceptable quality the deformable registration didn’t improve the alignment, this was true of all metrics employed. If the analysis is separated into cases where the rigid alignment was ranked as unacceptable the deformable registration significantly improved the alignment, 4.62mm residual error in landmarks as compared to 5.72mm residual error in rigid alignments with a p-value of 0.0008. Conclusion: This paradigm provides an ideal testing ground for MR to CT deformable registration algorithms by allowing for inter-modality comparisons of multi-modality registrations. Consistent positioning, bowel and bladder preparation may Result in higher quality rigid registrations than typically achieved which limits the impact of deformable registrations. In this study cases where significant differences exist, deformable registrations provide significant value.

60 APPLIED LIFE SCIENCES↗