Ferumoxytol-enhanced 4D multiphase, steady-state imaging with magnetic resonance in congenital heart disease: ventricular volume and function across 2D and 3D software platforms.

Background: Quantitative ventricular volumetry and function are important in the management of congenital heart disease (CHD). Ferumoxytol-enhanced (FE) 4D multiphase, steady state imaging with contrast enhancement (MUSIC) enables high-resolution, 3D cardiac phase-resolved magnetic resonance imaging (MRI) of the beating heart and extracardiac vessels in a single acquisition and without concerns about renal impairment. We aim to evaluate the semi-automatic quantification of ventricular volumetry and function of 4D MUSIC MRI using 2D and 3D software platforms. Methods: This HIPAA-compliant and IRB-approved study prospectively recruited 50 children with CHD (3 days to 18 years) who underwent 4D MUSIC MRI at 3.0T between 2013-2017 for clinical indications. Each patient was either intubated in the neonatal intensive care unit (NICU) or underwent general anesthesia at MRI suite. For 2D analysis, we reformatted MUSIC images in Digital Imaging and Communications in Medicine (DICOM) format into ventricular short-axis slices with zero interslice gap. For 3D analysis, we imported DICOMs into a commercially available 3D software platform. Using semi-automatic thresholding, we quantified biventricular volume and ejection fraction (EF). We assessed the bias between MUSIC-derived 2D vs. 3D measurements and correlation between MUSIC vs. conventional 2D balanced steady-state free precession (bSSFP) cine images. We evaluated intra- and inter-observer agreement. Results: There was a high degree of correlation between MUSIC-derived volumetric and functional measurements using 2D vs. 3D software (r=0.99, P<0.001). Volumes derived using 3D software platforms were larger than 2D by 0.2 to 2.0 mL/m2 whereas EF measurements were higher by 1.2-3.0%. MUSIC volumetric and functional measures derived from 2D and 3D software platforms corresponded highly with those derived from multi-slice SSFP cine images (r=0.99, P<0.001). The mean difference in volume for reformatted 4D MUSIC relative to bSSFP cine was 1.5 to 3.9 mL/m2. Intra- and inter-observer reliability was excellent. Conclusions: Accurate and reliable ventricular volumetry and function can be derived from FE 4D MUSIC MRI studies using commercially available 2D and 3D software platforms. If fully validated in multicenter studies, the FE 4D-MUSIC pulse sequence may supercede conventional multislice 2D cine cardiovascular MRI acquisition protocols for functional evaluation of children with complex CHD.

A Machine Learning Algorithm to Estimate Sarcopenia on Abdominal CT.

RATIONALE AND OBJECTIVES: To assess whether a fully-automated deep learning system can accurately detect and analyze truncal musculature at multiple lumbar vertebral levels and muscle groupings on abdominal CT for potential use in the detection of central sarcopenia. MATERIALS AND METHODS: A computer system for automated segmentation of truncal musculature groups was designed and created. Abdominal CT scans of 102 sequential patients (mean age 68 years, range 59-81 years; 53 women, 49 men) conducted between January 2015 and February 2015 were assembled as a data set. Truncal musculature was manually segmented on axial CT images at multiple lumbar vertebral levels as reference standard data, divided into training and testing subsets, and analyzed by the system. Dice similarity coefficients were calculated to evaluate system performance. IRB approval was obtained, with waiver of informed consent in this retrospective study. RESULTS: System performance as gauged by the Dice coefficients, for detecting the total abdominal muscle cross-section at the level of the third and fourth lumbar vertebrae, were, respectively, 0.953 ± 0.015 and 0.953 ± 0.011 for the training set, and 0.938 ± 0.028 and 0.940 ± 0.026 for the testing set. Dice coefficients for detecting total psoas muscle cross-section at the level of the third and fourth lumbar vertebrae, were, respectively, 0.942 ± 0.040 and 0.951 ± 0.037 for the training set, and 0.939 ± 0.028 and 0.946 ± 0.032 for the testing set. CONCLUSION: This system fully-automatically and accurately segments multiple muscle groups at all lumbar spine levels on abdominal CT for detection of sarcopenia.

Aerobic exercise in anthracycline-induced cardiotoxicity: a systematic review of current evidence and future directions.

Cancer and cardiovascular disease are major causes of morbidity and mortality worldwide. Older cancer patients often wrestle with underlying heart disease during cancer therapy, whereas childhood cancer survivors are living long enough to face long-term unintended cardiac consequences of cancer therapies, including anthracyclines. Although effective and widely used, particularly in the pediatric population, anthracycline-related side effects including dose-dependent association with cardiac dysfunction limit their usage. Currently, there is only one United States Food and Drug Administration-approved drug, dexrazoxane, available for the prevention and mitigation of cardiotoxicity related to anthracycline therapy. While aerobic exercise has been shown to reduce cardiovascular complications in multiple diseases, its role as a therapeutic approach to mitigate cardiovascular consequences of cancer therapy is in its infancy. This systematic review aims to summarize how aerobic exercise can help to alleviate unintended cardiotoxic side effects and identify gaps in need of further research. While published work supports the benefits of aerobic exercise, additional clinical investigations are warranted to determine the effects of different exercise modalities, timing, and duration to identify optimal aerobic training regimens for reducing cardiovascular complications, particularly late cardiac effects, in cancer survivors exposed to anthracyclines.

Cardiac MRI: a Translational Imaging Tool for Characterizing Anthracycline-Induced Myocardial Remodeling.

Cardiovascular side effects of cancer therapeutics are the leading causes of morbidity and mortality in cancer survivors. Anthracyclines (AC) serve as the backbone of many anti-cancer treatment strategies, but dose-dependent myocardial injury limits their use. Cumulative AC exposure can disrupt the dynamic equilibrium of the myocardial microarchitecture while repeated injury and repair leads to myocyte loss, interstitial myocardial fibrosis, and impaired contractility. Although children are assumed to have greater myocardial plasticity, AC exposure at a younger age portends worse prognosis. In older patients, there is lower overall survival once they develop cardiovascular disease. Because aberrations in the myocardial architecture predispose the heart to a decline in function, early detection with sensitive imaging tools is crucial and the implications for resource utilization are substantial. As a comprehensive imaging modality, cardiac magnetic resonance (CMR) imaging is able to go beyond quantification of ejection fraction and myocardial deformation to characterize adaptive microstructural and microvascular changes that are important to myocardial tissue health. Herein, we describe CMR as an established translational imaging tool that can be used clinically to characterize AC-associated myocardial remodeling.

Nanoporous Materials Can Tune the Critical Point of a Pure Substance.

Molecular simulations and NMR relaxometry experiments demonstrate that pure benzene or xylene confined in isoreticular metal-organic frameworks (IRMOFs) exhibit true vapor-liquid phase equilibria where the effective critical point may be reduced by tuning the structure of the MOF. Our results are consistent with vapor and liquid phases extending over many MOF unit cells. These results are counterintuitive since the MOF pore diameters are approximately the same length scale as the adsorbate molecules. As applications of these materials in catalysis, separations, and gas storage rely on the ability to tune the properties of adsorbed molecules, we anticipate that the ability to systematically control the critical point, thereby preparing spatially inhomogeneous local adsorbate densities, could add a new design tool for MOF applications.

An Improved Index of Image Quality for Task-based Performance of CT Iterative Reconstruction across Three Commercial Implementations.

PURPOSE: To develop and validate a metric of computed tomographic (CT) image quality that incorporates the noise texture and resolution properties of an image. MATERIALS AND METHODS: Images of the American College of Radiology CT quality assurance phantom were acquired by using three commercial CT systems at seven dose levels with filtered back projection (FBP) and iterative reconstruction (IR). Image quality was characterized by the contrast-to-noise ratio (CNR) and a detectability index (d') that incorporated noise texture and spatial resolution. The measured CNR and d' were compared with a corresponding observer study by using the Spearman rank correlation coefficient to determine how well each metric reflects the ability of an observer to detect subtle lesions. Statistical significance of the correlation between each metric and observer performance was determined by using a Student t distribution; P values less than .05 indicated a significant correlation. Additionally, each metric was used to estimate the dose reduction potential of IR algorithms while maintaining image quality. RESULTS: Across all dose levels, scanner models, and reconstruction algorithms, the d' correlated strongly with observer performance in the corresponding observer study (ρ = 0.95; P < .001), whereas the CNR correlated weakly with observer performance (ρ = 0.31; P = .21). Furthermore, the d' showed that the dose-reduction capabilities differed between clinical implementations (range, 12%-35%) and were less than those predicted from the CNR (range, 50%-54%). CONCLUSION: The strong correlation between the observer performance and the d' indicates that the d' is superior to the CNR for the evaluation of CT image quality. Moreover, the results of this study indicate that the d' improves less than the CNR with the use of IR, which indicates less potential for IR dose reduction than previously thought.

Health locus of control and self-efficacy predict back pain rehabilitation outcomes.

INTRODUCTION: Chronic back pain treatments have generally been costly and/or ineffective despite advances in medical technology. Patient selection and factors intrinsic to patients, including beliefs and behaviors, have been increasingly looked upon as possible predictive factors for success following multidisciplinary intervention for chronic back pain. The current study investigated the value of using patients' perceived control over health changes (health locus of control) and their perceived ability to engage in pain management behaviors (pain-related self-efficacy) to predict physical and mental health outcomes. METHODS: We retrospectively analyzed 61 patients who completed a two-week multidisciplinary chronic back pain rehabilitation program at our institution between 2007 and 2009. Patient demographics were identified and categorized. Pre- and post-intervention functional surveys, including the Multidimensional Health Locus of Control Form C, Chronic Pain Self-Efficacy Scale, Medical Outcomes Study Short Form-36 Version 2, Beck Depression Inventory-II, and Oswestry Disability Index Version 2, were used to evaluate benefit from back pain intervention and to examine patient factors that may predict physical and mental health outcomes. RESULTS: Participants included 28 males and 33 females, ages 28 to 72, completing chronic back pain rehabilitation. Locus of control, self-efficacy, and physical and mental health demonstrated treatment-related changes, with notable improvements in physical and mental health. Regression analyses examined the value of pre-treatment health locus of control and pain-related self-efficacy as predictors of physical and mental health one month following treatment. Higher internal and lower doctor health locus of control, and higher self-efficacy at baseline predicted higher lift scores one month after treatment (p <. 05; p <. 01; p <. 01, respectively). Higher baseline self-efficacy also predicted better physical functioning (p <. 01) and lower disability (p <. 01) at one month. CONCLUSIONS: In addition to supporting the multiple benefits of multidisciplinary rehabilitation, this study suggests that pain-related self-efficacy and health locus of control may be valuable predictors of treatment benefit for chronic back pain patients. These results provide direction in screening for factors that may maximize the potential to benefit from multidisciplinary intervention for chronic back pain.

Dispersion of T1 and T2 nuclear magnetic resonance relaxation in crude oils.

Crude oils, which are complex mixtures of hydrocarbons, can be characterized by nuclear magnetic resonance diffusion and relaxation methods to yield physical properties and chemical compositions. In particular, the field dependence, or dispersion, of T1 relaxation can be used to investigate the presence and dynamics of asphaltenes, the large molecules primarily responsible for the high viscosity in heavy crudes. However, the T2 relaxation dispersion of crude oils, which provides additional insight when measured alongside T1, has yet to be investigated systematically. Here we present the field dependence of T1-T2 correlations of several crude oils with disparate densities. While asphaltene and resin-containing crude oils exhibit significant T1 dispersion, minimal T2 dispersion is seen in all oils. This contrasting behavior between T1 and T2 cannot result from random molecular motions, and thus, we attribute our dispersion results to highly correlated molecular dynamics in asphaltene-containing crude oils.

Atopic keratoconjunctivitis: A review.

Atopic keratoconjunctivitis is a chronic noninfectious inflammatory condition and is one of the most severe ophthalmic complications associated with atopic dermatitis. It requires prompt and effective treatment to prevent permanent vision loss. Complications of atopic keratoconjunctivitis include cataracts, keratoconus, infectious keratitis, blepharitis, tear dysfunction, and steroid-induced glaucoma. All treatment for atopic keratoconjunctivitis should be managed in conjunction with an ophthalmologist, and immediate referral is indicated when there is moderate to severe irritation, increased redness, discharge, or any visual symptoms. Treatment options include a combination of mast cell inhibitors, antihistamines, corticosteroids, and calcineurin inhibitors.

Demographics, clinical practice patterns, and concerns of physiatrists in the State of Hawai'i: 2011.

BACKGROUND: Although the State of Hawai'i overall may have an adequate number of physiatrists, there are physiatrist shortages on the neighbor islands. This study describes the demographics, practice type, and most important concerns of current practicing physiatrists within the state of Hawai'i. METHODS: A phone survey was conducted of 44 actively practicing Hawai'i physiatrists. Eligible participants were members of either the American Academy of Physical Medicine and Rehabilitation (AAPMR) or the Hawai'i Society of Physical Medicine and Rehabilitation. RESULTS: Thirty-six of 44 local physiatrists responded to the survey. Thirty-two of the thirty-six (89%) respondents were currently practicing on O'ahu, nine (25% of respondents) completed medical school at University of Hawai'i, 19 (58% of respondents) were not planning on recruiting in their practice for at least five years and the physiatrists' most common concerns included poor reimbursement, practice management problems, and high workload. DISCUSSION: Further recruitment efforts should be tailored to attracting physiatrists to our neighbor islands. Increasing reimbursement, addressing hospital administration issues, developing a musculoskeletal fellowship program, and increasing incentives to practice on neighbor islands are proposed changes that would directly address the concerns of Hawai'i's physiatrists.

Facial recognition software success rates for the identification of 3D surface reconstructed facial images: implications for patient privacy and security.

Image de-identification has focused on the removal of textual protected health information (PHI). Surface reconstructions of the face have the potential to reveal a subject's identity even when textual PHI is absent. This study assessed the ability of a computer application to match research subjects' 3D facial reconstructions with conventional photographs of their face. In a prospective study, 29 subjects underwent CT scans of the head and had frontal digital photographs of their face taken. Facial reconstructions of each CT dataset were generated on a 3D workstation. In phase 1, photographs of the 29 subjects undergoing CT scans were added to a digital directory and tested for recognition using facial recognition software. In phases 2-4, additional photographs were added in groups of 50 to increase the pool of possible matches and the test for recognition was repeated. As an internal control, photographs of all subjects were tested for recognition against an identical photograph. Of 3D reconstructions, 27.5% were matched correctly to corresponding photographs (95% upper CL, 40.1%). All study subject photographs were matched correctly to identical photographs (95% lower CL, 88.6%). Of 3D reconstructions, 96.6% were recognized simply as a face by the software (95% lower CL, 83.5%). Facial recognition software has the potential to recognize features on 3D CT surface reconstructions and match these with photographs, with implications for PHI.

Tumor volume measurement errors of RECIST studied with ellipsoids.

PURPOSE: The authors investigate the extent to which Response Evaluation Criteria in Solid Tumors (RECIST) can predict tumor volumes in ideal geometric settings and using clinical data. METHODS: The authors consider a hierarchy of models including uniaxial ellipsoids, general ellipsoids, and composites of ellipsoids, using both analytical and numerical techniques to show how well RECIST can predict tumor volumes in each case. The models have certain features that are compared to clinical data. RESULTS: The principal conclusion is that a change in the reported RECIST value needs to be a factor of at least 1.2 to achieve a 95% confidence that one ellipsoid is larger than another assuming the ratio of maximum to minimum diameters is no more than 2, an assumption that is reasonable for some classes of tumors. There is a significant probability that RECIST will select a tumor other than the largest due to orientation effects of nonspherical tumors: in previously reported malignoma data, RECIST would have selected a tumor other than the largest in 9% of the cases. Also, the widely used spherical model connecting RECIST values for a single tumor to volumes overestimates these volumes. CONCLUSIONS: RECIST imposes a limit on the ability to determine tumor volumes, which is greater than the limit imposed by modem medical computed tomography machines. It is also likely the RECIST limit is above natural biological variability of stable lesions. The authors recommend the study of such natural variability as a fruitful avenue for further study.

RECIST versus volume measurement in medical CT using ellipsoids of known size.

Two hundred eighty three uniaxial ellipsoids with sizes from 4 mm to 11 mm were measured with a coordinate measuring matching (CMM) and also scanned using a medical computed tomography (CT) machine. Their volumes were determined by counting voxels over a threshold, as well as using equivalent volumes from the length given by the RECIST 1.1 criterion (Response Evaluation Criteria in Solid Tumors). The volumetric measurements yield an order of magnitude reduction in residuals compared to the CMM measurements than the residuals of the RECIST measurements also compared to the CMM measurements.

CT angiography of the cardiac valves: normal, diseased, and postoperative appearances.

Although echocardiography remains the principal imaging technique for assessment of the cardiac valves, contrast material-enhanced electrocardiographically gated computed tomographic (CT) angiography is proving to be an increasingly valuable complementary modality in this setting. CT angiography allows excellent visualization of the morphologic features and function of the normal valves, as well as of a wide range of valve diseases, including congenital and acquired diseases, infectious endocarditis, and complications of valve replacement. The number, thickness, and opening and closing of the valve leaflets, as well as the presence of valve calcification, can be directly observed. CT angiography also permits simultaneous assessment of the valves and coronary arteries, which may prove valuable in presurgical planning. Unlike echocardiography and magnetic resonance imaging, however, CT angiography requires ionizing radiation and does not provide a direct measure of the valvular pressure gradient. Nevertheless, with further development of related imaging techniques, CT angiography can be expected to play an increasingly important role in the evaluation of the cardiac valves. Supplemental material available at http://radiographics.rsna.org/cgi/content/full/29/5/1393/DC1.

Use of a computer-aided detection system to detect missed lung cancer at chest radiography.

PURPOSE: To study the ability of a computer-aided detection (CAD) system to detect lung cancer overlooked at initial interpretation by the radiologist. MATERIALS AND METHODS: Institutional review board approval was given for this study. Patient consent was not required; a HIPAA waiver was granted because of the retrospective nature of the data collection. In patients with lung cancer diagnosed from 1995 to 2006 at two institutions, each chest radiograph obtained prior to tumor discovery was evaluated by two radiologists for an overlooked lesion. The size and location of the nodules were documented and graded for subtlety (grades 1-4, 1 = very subtle). Each radiograph with a missed lesion was analyzed by a commercial CAD system, as was the follow-up image at diagnosis. An age- and sex-matched control group was used to assess CAD false-positive rates. RESULTS: Missed lung cancer was found in 89 patients (age range, 51-86 years; mean age, 65 years; 80 men, nine women) on 114 radiographs. Lesion size ranged from 0.4 to 5.5 cm (mean, 1.8 cm). Lesions were most commonly peripheral (n = 63, 71%) and in upper lobes (n = 67, 75%). Lesion subtlety score was 1, 2, 3, or 4 on 43, 49, 17, and five radiographs, respectively. CAD identified 53 (47%) and 46 (52%) undetected lesions on a per-image and per-patient basis, respectively. The average size of lesions detected with CAD was 1.73 cm compared with 1.85 cm for lesions that were undetected (P = .47). A significant difference (P = .017) was found in the average subtlety score between detected lesions (score, 2.06) and undetected lesions (score, 1.68). An average of 3.9 false-positive results occurred per radiograph; an average of 2.4 false-positive results occurred per radiograph for the control group. CONCLUSION: CAD has the potential to detect approximately half of the lesions overlooked by human readers at chest radiography.

Corneal epithelial opacity in dysfunctional tear syndrome.

PURPOSE: To compare the appearance of the superficial corneal epithelium in patients with dysfunctional tear syndrome (DTS) and that of an asymptomatic control group using laser scanning confocal microscopy and to determine the correlations between confocal microscopic findings and clinical severity parameters. DESIGN: Prospective case-control study. METHODS: Thirty-one patients with newly diagnosed DTS and 21 asymptomatic control subjects were evaluated for this study. Subjects with DTS were classified into 4 levels of clinical severity (DTS 1 through 4) based on the Delphi dry eye panel report criteria. The Heidelberg Retina Tomograph 2 Rostock Cornea Module (Heidelberg Engineering GmbH, Heidelberg, Germany) laser scanning confocal microscope was used to image the superficial corneal epithelium. Areas of single or multiple opaque superficial epithelial cells were measured as a percentage of the 400 x 400-microm(2) field area in 4 randomly selected confocal images from each eye. Spearman correlations between the confocal findings and severity of symptoms, visual acuity, and ocular surface signs were calculated. RESULTS: The mean area of opaque superficial corneal epithelial cells was significantly greater in DTS patients than in normal subjects (P < .0001). Significant differences were observed between the DTS severity groups and the control group (P < .001), except for the DTS 1 group. The area of opaque cells significantly increased with level of clinical severity. The confocal findings showed significant correlation with clinical severity parameters, including blurred vision symptoms (r = 0.86; P = .0001), best-corrected visual acuity (Spearman r = 0.4; P = .03), conjunctival lissamine green staining scores (Spearman r = 0.4; P = .026), corneal fluorescein staining scores (Spearman r = 0.5; P = .002), and videokeratoscopic surface regularity index (Spearman r = 0.5; P = .02). CONCLUSIONS: Morphologic changes in the superficial corneal epithelium of DTS patients detected by laser scanning confocal microscopy correlates with blurred vision symptoms and objective severity parameters. Objective confocal image analysis of the superficial corneal epithelium may prove useful for classifying DTS severity and for monitoring the efficacy of therapies.

Production and activity of matrix metalloproteinase-9 on the ocular surface increase in dysfunctional tear syndrome.

PURPOSE: To evaluate production and activity of metalloproteinase (MMP)-9 on the ocular surface of patients with dysfunctional tear syndrome (DTS) and determine any correlation between MMP-9 activity and clinical parameters. METHODS: Forty-six patients with newly diagnosed DTS and 18 control subjects were recruited. Complete ocular surface examinations were performed. Tear MMP-9 activity was assessed with an MMP-9 activity assay in 1 microL of unstimulated tear fluid. Using conjunctival epithelial cells from 19 patients with DTS and 16 controls, levels of MMP-9 and its regulating cytokine mRNA transcripts were evaluated by semiquantitative real-time PCR. RESULTS: Each of four DTS severity-based groups had significantly higher mean MMP-9 activities than did the control group, which was 8.39 +/- 4.70 ng/mL. The DTS4 group had the highest MMP-9 activity (381.24 +/- 142.83 ng/mL), for which the mean was significantly higher than that of other DTS groups. In addition, patients with DTS had significantly higher levels of IL-1beta, IL-6, TNF-alpha, and TGF-beta1 mRNA transcripts in their conjunctival epithelia than did the control subjects. Tear MMP-9 activities showed significant correlation with symptom severity scores, decreased low-contrast visual acuity, fluorescein tear break-up time, corneal and conjunctival fluorescein staining, topographic surface regularity index (SRI), and percentage area of abnormal superficial corneal epithelia by confocal microscopy. CONCLUSIONS: Tear MMP-9 activity was significantly higher in patients with DTS. This activity was associated with increased mRNA expression of MMP-9 and its regulating genes and correlated strongly with clinical parameters. MMP-9 appears to be a potentially useful biomarker for diagnosing, classifying, and monitoring DTS.