The 2021 SIIM-FISABIO-RSNA Machine Learning COVID-19 Challenge: Annotation and Standard Exam Classification of COVID-19 Chest Radiographs.

We describe the curation, annotation methodology, and characteristics of the dataset used in an artificial intelligence challenge for detection and localization of COVID-19 on chest radiographs. The chest radiographs were annotated by an international group of radiologists into four mutually exclusive categories, including "typical," "indeterminate," and "atypical appearance" for COVID-19, or "negative for pneumonia," adapted from previously published guidelines, and bounding boxes were placed on airspace opacities. This dataset and respective annotations are available to researchers for academic and noncommercial use.

Wavelet-based scaling indices for breast cancer diagnostics.

Mammography is routinely used to screen for breast cancer. However, the radiological interpretation of mammogram images is complicated by the heterogeneous nature of normal breast tissue and the fact that cancers are often of the same radiographic density as normal tissue. In this work, we use wavelets to quantify spectral slopes of breast cancer cases and controls and demonstrate their value in classifying images. In addition, we propose asymmetry statistics to be used in forming features, which improve the classification result. For the best classification procedure, we achieve approximately 77% accuracy (sensitivity=73%, specificity=84%) in classifying mammograms with and without cancer. Copyright © 2017 John Wiley & Sons, Ltd.

[Pharmacological fMRI : new possibilities for assessing the efficacy of analgesic agents]. / Pharmakologisches FMRT : Neue Möglichkeiten in der Wirksamkeitsprüfung von Analgetika.

Pain is a complex subjective phenomenon that so far cannot be objectively quantified by any standardized procedure. This fact renders it also difficult to measure the efficacy of analgesic drugs. In recent years the application of functional magnetic resonance imaging (fMRI) has significantly increased our current knowledge about the brain physiological correlates of pain in humans. The technique is non-invasive and detects the increased blood flow into neuronally active brain regions based on the so-called BOLD (blood oxygenation level dependent) effect of T2-weighted MRI. This paper gives an overview of the application of pharmacological fMRI (phfMRI) as an approach to evaluate the efficacy of analgesics. In contrast to EEG- and MEG-based methods phfMRI allows more flexibility in the design of experimental paradigms and stimulus protocols to account for the diversity of clinical pain types (inflammatory pain, tactile allodynia etc.) or their dependence upon psychological circumstances (anxiety, depression, stress) in which pain occurs. However, in order to specifically refer results from phfMRI to the neuronal processes underlying pain, future research needs to increase the understanding of the mechanisms underlying the neurovascular coupling reaction represented by the BOLD technique. The same applies for the influence of cerebrovascular diseases on the BOLD response.

An Adaptive Seismocardiography (SCG)-ECG Multimodal Framework for Cardiac Gating Using Artificial Neural Networks.

To more accurately trigger data acquisition and reduce radiation exposure of coronary computed tomography angiography (CCTA), a multimodal framework utilizing both electrocardiography (ECG) and seismocardiography (SCG) for CCTA prospective gating is presented. Relying upon a three-layer artificial neural network that adaptively fuses individual ECG- and SCG-based quiescence predictions on a beat-by-beat basis, this framework yields a personalized quiescence prediction for each cardiac cycle. This framework was tested on seven healthy subjects (age: 22-48; m/f: 4/3) and eleven cardiac patients (age: 31-78; m/f: 6/5). Seventeen out of 18 benefited from the fusion-based prediction as compared to the ECG-only-based prediction, the traditional prospective gating method. Only one patient whose SCG was compromised by noise was more suitable for ECG-only-based prediction. On average, our fused ECG-SCG-based method improves cardiac quiescence prediction by 47% over ECG-only-based method; with both compared against the gold standard, B-mode echocardiography. Fusion-based prediction is also more resistant to heart rate variability than ECG-only- or SCG-only-based prediction. To assess the clinical value, the diagnostic quality of the CCTA reconstructed volumes from the quiescence derived from ECG-, SCG- and fusion-based predictions were graded by a board-certified radiologist using a Likert response format. Grading results indicated the fusion-based prediction improved diagnostic quality. ECG may be a sub-optimal modality for quiescence prediction and can be enhanced by the multimodal framework. The combination of ECG and SCG signals for quiescence prediction bears promise for a more personalized and reliable approach than ECG-only-based method to predict cardiac quiescence for prospective CCTA gating.

Echocardiography as an indication of continuous-time cardiac quiescence.

Cardiac computed tomography (CT) angiography using prospective gating requires that data be acquired during intervals of minimal cardiac motion to obtain diagnostic images of the coronary vessels free of motion artifacts. This work is intended to assess B-mode echocardiography as a continuous-time indication of these quiescent periods to determine if echocardiography can be used as a cost-efficient, non-ionizing modality to develop new prospective gating techniques for cardiac CT. These new prospective gating approaches will not be based on echocardiography itself but on CT-compatible modalities derived from the mechanics of the heart (e.g. seismocardiography and impedance cardiography), unlike the current standard electrocardiogram. To this end, echocardiography and retrospectively-gated CT data were obtained from ten patients with varied cardiac conditions. CT reconstructions were made throughout the cardiac cycle. Motion of the interventricular septum (IVS) was calculated from both echocardiography and CT reconstructions using correlation-based, deviation techniques. The IVS was chosen because it (1) is visible in echocardiography images, whereas the coronary vessels generally are not, and (2) has been shown to be a suitable indicator of cardiac quiescence. Quiescent phases were calculated as the minima of IVS motion and CT volumes were reconstructed for these phases. The diagnostic quality of the CT reconstructions from phases calculated from echocardiography and CT data was graded on a four-point Likert scale by a board-certified radiologist fellowship-trained in cardiothoracic radiology. Using a Wilcoxon signed-rank test, no significant difference in the diagnostic quality of the coronary vessels was found between CT volumes reconstructed from echocardiography- and CT-selected phases. Additionally, there was a correlation of 0.956 between the echocardiography- and CT-selected phases. This initial work suggests that B-mode echocardiography can be used as a tool to develop CT-compatible gating techniques based on modalities derived from cardiac mechanics rather than relying on the ECG alone.

Noninvasive evaluation of global left ventricular function with use of cine nuclear magnetic resonance.

Previous reports have validated the accuracy of nuclear magnetic resonance (NMR) imaging for quantitating ventricular volumes and myocardial mass. In this study, a new rapid NMR imaging method, cine NMR imaging, was used to compare left ventricular volumes determined from the transverse plane and short-axis plane in healthy volunteers and patients with dilated cardiomyopathy. With use of the short-axis plane, left ventricular mass at end-systole and end-diastole were determined and left ventricular systolic wall thickening at three different levels was assessed. For validation in the current study, cine NMR imaging and two-dimensional echocardiographic measurements of left ventricular volumes were correlated. Left ventricular volumes of the normal volunteers (end-systolic volume = 34 +/- 3.8 ml, end-diastolic volume = 90.4 +/- 7.2 ml) and patients with cardiomyopathy (end-systolic volume = 173 +/- 28.3 ml, end-diastolic volume = 219.5 +/- 29.6 ml) obtained in the transverse plane were nearly identical to those obtained in the short-axis plane (normal volunteers, end-systolic volume = 30.3 +/- 3.5 ml, end-diastolic volume = 84.7 +/- 7.0 ml and patients with cardiomyopathy, end-systolic volume = 179.1 +/- 27.8 ml, end-diastolic volume = 227 +/- 30.9 ml) and correlated highly (r = 0.91) with volumes obtained by two-dimensional echocardiography. Assessment of left ventricular mass over a broad range using cine NMR imaging in a short-axis plane was identical at end-systole (normal volunteers, 117 +/- 10 g; patients with cardiomyopathy, 202 +/- 20 g) and end-diastole (normal volunteers, 115 +/- 10 g; patients with cardiomyopathy, 194 +/- 21 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium inhibition of glycolysis contributes to ischaemic injury.

STUDY OBJECTIVE: The purpose of the study was to confirm that [Ca2+]i and .[H+]i increase during ischaemia in hypertensive hearts but not in thyrotoxic hearts, and that the rise in [Ca2+]i and [H+]i inhibits glycolysis, causing a rise in phosphomonoester sugars and thereby influencing postischaemic recovery. DESIGN: Rats were made hypertensive by aortic banding and thyrotoxic by injection of L-thyroxine. [Ca2+]i was studied in isolated hearts by surface fluorometry assessing calcium dependent changes in the fluorescent dye INDO-1, while [pH]i and phosphomonoester sugars were studied by 31P nuclear magnetic resonance (NMR). Global ischaemia was carried out by turning off all flow to the heart for 30 min. Hearts were then reperfused for 30 min. SUBJECTS: 72 Sprague-Dawley rats, weight 500-600 g, were used. Left ventricular hypertrophy was generated by aortic banding in 36, half of which were treated with verapamil. Eighteen were injected with L-thyroxine and there were 18 controls. MEASUREMENTS AND RESULTS: With all groups, developed pressure immediately declined after the onset of global ischaemia. During ischaemia the phosphomonoester sugars rose less in the hearts of thyrotoxic rats and the verapamil treated aortic constricted rats than in those of untreated aortic constricted and normal rats. During ischaemia there was no significant difference in [pH]i among the four groups. During ischaemia intracellular calcium rose least in thyrotoxic and verapamil treated aortic constricted rats, and most in untreated aortic constricted and normal rats. Intracellular calcium rose 10-15 min after the onset of ischaemia in verapamil treated pressure overload and control hearts; calcium rose immediately after the onset of ischaemia in the untreated aortic constricted hearts, but negligibly in hearts from thyroxine treated animals. Verapamil treatment of the aortic constricted hearts prevented the rise in intracellular calcium, and attenuated phosphomonoester sugar accumulation. Postischaemic recovery was complete in hearts in thyroxine treated and verapamil treated aortic constricted rats, but not in hearts from untreated aortic constricted and normal rats. Postischaemic recovery was inversely related to ischaemic diastolic [Ca2+]i and phosphomonoester sugar levels, but was not related to ischaemic values for [pH]i. CONCLUSIONS: Postischaemic recovery may depend on the ability of the cell to maintain mitochondrial activity as evidenced by oxygen consumption, thereby controlling the voltage of the cell, and influencing the ability of the myocardium to maintain its calcium homeostasis.

Ethanol protects the heart against the calcium paradox injury.

Rat hearts were depleted of Ca2+ (less than 10(-9) M) for 10 min, followed by 15 min of Ca2+-repletion. The calcium paradox injury occurs during Ca2+-repletion, after a period of calcium depletion. The calcium paradox injury was assessed by percent recovery (hemodynamics, [Ca2+]i, and energy levels) during Ca2+-repletion. A decrease in Na+ concentration during Ca2(+)-depletion did not allow for recovery during Ca2(+)-repletion, however 2.5% and 5% ethanol during Ca2(+)-depletion allowed for an approximate 50% recovery during Ca2(+)-repletion. A combination of ethanol (2.5% or 5%) with a low extracellular Na+ concentration (88 mM) allowed for complete recovery. Ethanol prevented a depletion of diastolic [Ca2+]i during Ca2(+)-depletion, and allowed for a return of normal diastolic [Ca2+]i during Ca2(+)-repletion. Ethanol modulates the activity of the Na+/Ca2+ exchanger and protects against the Ca2(+)-paradox injury.

Influence of drugs on diseased states of the heart. A 31P NMR and [Ca]i study.

Phosphorus 31 magnetic resonance spectroscopy (MRS) can be used to monitor the direct effect of drugs on energy metabolites of the heart. Using the isolated perfused heart of the cardiomyopathic hamster (late heart failure), drugs that exacerbate the diastolic level of calcium [Ca]i (e.g., dobutamine and digoxin) augment intracellular phosphomonoester sugars, while drugs which increase cyclic adenosine mono-phosphate [cAMP]i (e.g. isoprel, dibutyryl cAMP, and amrinone) lower phosphomonoester sugars. The phosphomonoester sugars are inversely related to developed pressure and oxygen consumption. Accumulation of sugar phosphates indicates inhibition of glycolysis and limited delivery of pyruvate to the mitochondria, thereby decreasing oxygen consumption. The phosphorylation potential obtained from standardized 31P MRS values showed a direct relationship to the rate pressure product in hamsters with heart failure; however, the two parameters were inversely related in control hamsters.

Diagnostic and prognostic value of DNA image cytometry in myelodysplasia.

The DNA content of erythropoietic cells from 10 patients with refractory anaemia (RA) with megaloblastic changes, who subsequently developed acute non-lymphoblastic leukaemia (ANL), and from seven patients with megaloblastic marrow aspirates due to pernicious anaemia were compared by DNA image cytometry. The DNA distribution, the rate of aneuploid cells exceeding 5c (5cER), and the square deviation index of DNA values from the normal 2c-peak (2cDI) were recorded. Both variables were of diagnostic and prognostic importance for epithelial tumours, malignant lymphomas, and dysplastic lesions. A rate of 5cER greater than 0 was found in eight of 10 myelodysplastic, but in none of seven control cases. Hypodiploidy was equally pronounced in both groups of patients. The 5cE had the highest discriminative value of all variables calculated. The 2cDI was not significantly different in either group. In pernicious anaemia the 2cDI depended mainly on the percentage of S cells, reflecting the defect of DNA synthesis. In RA with megaloblastosis the 2cDI correlated with the percentage of G2 cells, reflecting G2 arrest. In the myelodysplastic group the 2cDI correlated positively with the length of time until ANL developed, indicating the prognostic relevance of 2cDI. Our findings show that in megaloblastic anaemia DNA image cytometry can distinguish myelodysplasia from pernicious anaemia and that it also provides prognostic information.

DNA grading of urothelial carcinoma of the bladder.

The prognostic influence of the nuclear DNA distribution pattern of human urothelial carcinomas of the bladder was investigated in 25 patients. Nuclear DNA content was measured by scanning microphotometry in Feulgen-stained histologic sections. A DNA malignancy grade (DNA-MG) ranging from 0.01 to 3 on a continuous scale was computed for each patient from the single cell DNA values. With the aid of the Cox proportional hazard regression model, DNA-MG was revealed as having a strong influence on survival time (p = 0.0004). Possible influences of other parameters (histological grade, stage, endoscopical tumor size and multiplicity, age) on survival could not be assessed in this model. This may be explained by the low number of cases and by the weakness of the influence of these parameters. Divided into two groups of patients according to their DNA-MG (group I: DNA-MG less than 1.5, group II: DNA-MG greater than or equal to 1.5), the histological grade had an influence on survival (p = 0.021). There was a good association of DNA-MG and histological grade (p = 0.05). In comparison to the histological grade DNA-MG seems to allow a more precise prognostic statement for the individual patient as it reveals additional information on survival for patients categorized according to their histological grade. We conclude that DNA-MG is an objective and scalar index for the prognosis of bladder carcinoma patients.

DNA-grading of malignant lymphomas. I. Prognostic significance, reproducibility and comparison with other classifications.

The prognostic significance of the DNA Malignancy Grade (DNA-MG) was tested for 83 malignant non Hodgkin lymphoma patients in comparison with three different subjective morphological classification systems (New Working Formulation for Clinical Usage, Rappaport and Kiel Classification). Monolayer smears prepared from paraffin embedded tissue and imprint smears from fresh cut lymph-nodes were investigated. Feulgen staining was performed automatically. The scalar DNA-MG was determined by rapid interactive DNA-cytometry, using an automatic microscope and a TV-image analysis system. A strong influence of the DNA-MG on length of survival was found. Compared with morphological classification systems, the DNA-MG was of greater prognostic validity as revealed by different statistical tests. Significant differences of survival probabilities between some groups with differences of 0.5 DNA-MG only were found. The interobserver reproducibility of this new prognostic index was found to be 95% within a range of +/-0.4 DNA-MG.

DNA-grading of malignant lymphomas. II. Correlation with clinical parameters.

The clinical significance of the DNA-malignancy grade (DNA-MG) was tested in 90 malignant lymphoma patients. Feulgen stained imprint smears from freshly cut lymph-nodes were investigated. DNA measurements were performed using various cytophotometers. The scalar DNA-MG, ranging from 0.1 to 3.0, was calculated from the variance of the tumor cells around the 2c peak. Except for the CLL, all entities of the Kiel classification for non-Hodgkin's malignant lymphomas showed considerable variation of the DNA-MGs. The DNA-MG, the age of the patients and the response to treatment were seen to have a significant influence on the survival time of non-Hodgkin's lymphoma patients. In high grade lymphoma patients of the Kiel classification, the DNA-MG was found to provide additional prognostic information. The DNA-MG was strongly correlated with the ESR, low albumin concentration, low lymphocyte counts in peripheral blood, clinical and pathological staging, and the response to treatment.

Cine magnetic resonance imaging: tomographic analysis of left ventricular function.

Cine magnetic resonance imaging has the attributes that enable its use as a method for quantitating the three-dimensional functional geometry of the ventricles. The completely noninvasive nature of this technique is advantageous for sequential studies needed to monitor evolution of cardiac disease and response to therapy. This article reviews the authors' experiences with this technique for the evaluation of left ventricular and valvular function.

Activation detection in event-related fMRI data based on spatio-temporal properties.

Template-based activation detection methods, such as cross-correlation, could be difficult to apply in event-related functional MRI data because accurate a priori knowledge about the activation signal patterns is often not available. As a result, several categories of template-free data analysis techniques have been introduced in the fMRI literature. One previously described template-free activation detection technique is based on the feature that activated voxels yield reproducible time course patterns as the subject undergoes the same simulation in repeated epochs. In this paper, spatial information is incorporated as a second feature and a combined univariate measure is formed. The resulting method is shown to offer measurable improvement in detecting activation regions in simulated data in a highly computationally efficient manner. Its practical utility is demonstrated with an experimental data set obtained with a visually guided motor paradigm.

Tissue reaction following endobronchial application of iopamidol and ioxithalamate in rats.

Lung tissue reaction to endobronchial application of iopamidol and ioxithalamate were compared by chest radiograph and histological examination in the rat. Radiographs cleared within hours in both groups. Tissue reaction after ioxithalamate application was significantly more pronounced than with iopamidol and included macrophage response, partial atelectasis, and intra-alveolar and interstitial oedema. Different from iopamidol, ioxithalamate induced a significantly stronger reaction than tracheotomy alone. Because no important significant side effects were observed on chest radiographs or in lung histology, iopamidol is recommended for the radiological examination of the gastrointestinal tract in patients with an increased risk of aspiration.

Immunopathology of AIDS (acquired immune deficiency syndrome) observations in 75 patients with pre-AIDS and AIDS.

Sequential changes in the morphology of immunocompetent and other organs, in the accompanying immunocytological and immunovirological measurements are described in 75 patients with lymphadenopathy syndrome and with AIDS. The data presented demonstrate a stepwise development of the disease from a hyperimmunization syndrome to T-cell immune deficiency. Excessive antigenic stimulation by a large number of infectious organisms or by transfusion of blood and blood products account for antigenic overloading and hyperimmunization. Among such infectious organisms are certain viruses which per se interfere with cells of the immune system as for instance Epstein-Barr virus, cytomegalovirus, and HTLV3. Developing immunological incompetence will favor the persistence of these and other infectious organisms enhancing the damage of the immune reactivity and finally allow lethal infections or malignant tumors to occur.

[Diagnosis of obstruction and stone passage following ESWL therapy (extracorporeal shock-wave lithotripsy)]. / Diagnostik von Obstruktion und Steinabgang nach ESWL-Therapie.

78 patients with ureteral formations of stone fragments after ESWL therapy have been controlled by both ultrasound and plain abdominal films. Detection of renal stone fragments was possible similarly by sonography or radiographs. The plain films demonstrated well location and length of the "Steinstrasse", which did not necessarily cause obstruction. Combination of sonography and plain abdominal film allows an easy follow-up after ESWL therapy, so i.v. urogramm is not aquired routinely.

[Magnetic resonance tomography (MRT) in pleural diseases. A comparison with CT and histopathological findings]. / Magnetresonanztomographie (MRT) bei Pleuraerkrankungen. Vergleich mit CT und histopathologischen Befunden.

The MRI and CT appearances in 48 patients with histologically confirmed benign and malignant pleural abnormalities were compared retrospectively. Abnormal pleural changes were shown in 47 out of the 48 patients by high signal intensity of the pleura in T2-weighted sequences and in contrast enhanced T1-weighted sequences on MRI. CT showed abnormalities in 45 out of 48 patients. Delineation of pleural and pulmonary changes by CT was possible in 13 out of 23 cases, and pleural disease from effusions in 15 out of 28 cases. T2-weighted MRI was successful in 14 out of 23 and 4 out of 28 cases, respectively. T1-weighted images after contrast were successful in 20 out of 23 and 22 out of 28 cases, respectively. Indications of malignant pleural disease were the presence of mediastinal or circumferential involvement or involvement of the entire pleura, thickness of more than 10 mm and nodular changes. The most reliable sign of malignancy was infiltration of the thoracic wall and the diaphragm; this was better demonstrated by MRI (18 out of 19 and 2 out of 2 cases) than by CT (14 out of 19 and 0 out of 2 cases).

Cytological grading of therapy-induced tumor regression in prostatic carcinoma: proposal of a new system.

Proposed in this article is a new system for the cytological grading of therapy-induced regression of prostatic carcinoma. Reversible and irreversible criteria in cytoplasm, nuclei, and nucleoli are distinguished and rated independently of each other on a scale of 0 to 2; the cellular regression grades r1-r3 are the sum of rating numbers. Criteria that are invalid for grading regression are pointed out. Results of the clinical testing of this grading system are presented.