Consistency of convolutional neural networks in dermoscopic melanoma recognition: A prospective real-world study about the pitfalls of augmented intelligence

BACKGROUND

Deep-learning convolutional neural networks (CNNs) have outperformed even experienced dermatologists in dermoscopic melanoma detection under controlled conditions. It remains unexplored how real-world dermoscopic image transformations affect CNN robustness.

OBJECTIVES

To investigate the consistency of melanoma risk assessment by two commercially available CNNs to help formulate recommendations for current clinical use.

METHODS

A comparative cohort study was conducted from January to July 2022 at the Department of Dermatology, University Hospital Basel. Five dermoscopic images of 116 different lesions on the torso of 66 patients were captured consecutively by the same operator without deliberate rotation. Classification was performed by two CNNs (CNN-1/CNN-2). Lesions were divided into four subgroups based on their initial risk scoring and clinical dignity assessment. Reliability was assessed by variation and intraclass correlation coefficients. Excisions were performed for melanoma suspicion or two consecutively elevated CNN risk scores, and benign lesions were confirmed by expert consensus (n = 3).

RESULTS

117 repeated image series of 116 melanocytic lesions (2 melanomas, 16 dysplastic naevi, 29 naevi, 1 solar lentigo, 1 suspicious and 67 benign) were classified. CNN-1 demonstrated superior measurement repeatability for clinically benign lesions with an initial malignant risk score (mean variation coefficient (mvc): CNN-1: 49.5(±34.3)%; CNN-2: 71.4(±22.5)%; p = 0.03), while CNN-2 outperformed for clinically benign lesions with benign scoring (mvc: CNN-1: 49.7(±22.7)%; CNN-2: 23.8(±29.3)%; p = 0.002). Both systems exhibited lowest score consistency for lesions with an initial malignant risk score and benign assessment. In this context, averaging three initial risk scores achieved highest sensitivity of dignity assessment (CNN-1: 94%; CNN-2: 89%). Intraclass correlation coefficients indicated 'moderate'-to-'good' reliability for both systems (CNN-1: 0.80, 95% CI:0.71-0.87, p < 0.001; CNN-2: 0.67, 95% CI:0.55-0.77, p < 0.001).

CONCLUSIONS

Potential user-induced image changes can significantly influence CNN classification. For clinical application, we recommend using the average of three initial risk scores. Furthermore, we advocate for CNN robustness optimization by cross-validation with repeated image sets.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04605822).

Nuclear Charge Radius of ^{26m}Al and Its Implication for V_{ud} in the Quark Mixing Matrix

Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ^{26m}Al. The measured isotope shift to ^{27}Al in the 3s^{2}3p ^{2}P_{3/2}^{○}→3s^{2}4s ^{2}S_{1/2} atomic transition enabled the first experimental determination of the nuclear charge radius of ^{26m}Al, resulting in R_{c}=3.130(15)  fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed β decay of ^{26m}Al. Its corrected Ft value, important for the estimation of V_{ud} in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s.

Discovery of Gamma Rays from the Quiescent Sun with HAWC

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1  TeV)^{-γ}, with A=(1.6±0.3)×10^{-12}  TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

Nuclear Charge Radii of the Nickel Isotopes ^{58-68,70}Ni

Collinear laser spectroscopy is performed on the nickel isotopes ^{58-68,70}Ni, using a time-resolved photon counting system. From the measured isotope shifts, nuclear charge radii R_{c} are extracted and compared to theoretical results. Three ab initio approaches all employ, among others, the chiral interaction NNLO_{sat}, which allows an assessment of their accuracy. We find agreement with experiment in differential radii δ⟨r_{c}^{2}⟩ for all employed ab initio methods and interactions, while the absolute radii are consistent with data only for NNLO_{sat}. Within nuclear density functional theory, the Skyrme functional SV-min matches experiment more closely than the Fayans functional Fy(Δr,HFB).

Charge Radius of the Short-Lived ^{68}Ni and Correlation with the Dipole Polarizability

We present the first laser spectroscopic measurement of the neutron-rich nucleus ^{68}Ni at the N=40 subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability α_{D} has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus ^{48}Ca. Three-particle-three-hole correlations in coupled-cluster theory substantially improve the description of the experimental data, which allows to constrain the neutron radius and neutron skin of ^{68}Ni.

Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

[Influence of immunomodulators on urological imaging]

BACKGROUND

Immune checkpoint inhibitors (ICI) have led to great advances in the therapy of metastatic renal cell and urothelial carcinoma. Currently ICI are approved for the first-line therapy of cisplatin-unfit patients (Atezolizumab, Pembrolizumab) and second-line therapy in patients with metastasized urothelial cancer (Atezolizumab, Nivolumab, Pembrolizumab). For the therapy of metastasized RCC, Nivolumab is approved as a second-line therapy and in combination with the CTLA‑4 antibody Ipilimumab as a first-line therapy.

OBJECTIVES

What does the optimized radiological follow-up and therapy response assessment for ICI, which differ in their pathways from common chemotherapeutics and anti-angiogenetic drugs, look like? What strategies are needed to meet the upcoming challenges concerning interpretation of the acquired images?

METHODS

A systematic literature search was carried out for urothelial and renal cell carcinoma.

RESULTS

Immune-related response criteria have been introduced to better characterize the imaging changes occurring under ICI, as monitoring response to immunotherapy still relies on RECIST.

CONCLUSIONS

To properly identify and predict response after treatment with ICI, additional studies with long-term follow-ups are needed. Because of the growing use of ICI, radiologists and urologist should be familiar with common imaging findings (such as pseudo progress) under immunotherapy to correctly interpret these findings in daily routine.

Laser Spectroscopy of Neutron-Rich Tin Isotopes: A Discontinuity in Charge Radii across the N=82 Shell Closure

The change in mean-square nuclear charge radii δ⟨r^{2}⟩ along the even-A tin isotopic chain ^{108-134}Sn has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions 5p^{2} ^{1}S_{0}→5p6 s^{1}P_{1} and 5p^{2} ^{3}P_{0}→5p6s ^{3}P_{1}. With the determination of the charge radius of ^{134}Sn and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the N=82 shell closure is established. A clear kink at the doubly magic ^{132}Sn is revealed, similar to what has been observed at N=82 in other isotopic chains with larger proton numbers, and at the N=126 shell closure in doubly magic ^{208}Pb. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, ^{132}Sn and ^{208}Pb, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects.

[Active surveillance in prostate cancer]

Prostate cancer remains among the most commonly diagnosed malignancies worldwide in men. In patients with low-risk prostate cancer, the risk of metastasis and mortality is very low; therefore, a tumor surveillance strategy can be used. In patients undergoing active surveillance, curative active therapy is postponed without compromising opportunities for cure until there is evidence of progression or the patient desires active therapy. The aim of active surveillance in prostate cancer patients is to minimize treatment-related toxicity without impairing patient survival. To maintain patients under active surveillance, the following criteria should be met: prostate-specific antigen (PSA) ≤10 ng/ml, Gleason score ≤6, cT1 or cT2a, ≤2 biopsy cores with <50% cancer involvement of every positive core. Follow-up in active surveillance patients is based on repeat biopsy, serial PSA measurements, and digital rectal examination.

Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433

In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.

Einfluss einer GnRH-Vakzine (Improvac®) auf Gewichtszunahmen und Schlachtkörperqualität von Ebern

Gegenstand und Ziel: Vergleich von Wirkung und Einfluss der GnRH-Vakzine Improvac® (Pfizer GmbH, Berlin) mit der chirurgischen Kastration bei männlichen Mastschweinen. Material und Methoden: Tiere der Gruppe K (n = 205) wurden in der 1. Lebenswoche (LW) chirurgisch kastriert, Schweine der Gruppe V (n = 191) in der 12. und 18. LW mit Improvac® vakziniert (2 ml subkutan). In der 1., 4., 12., 18. und 22. LW wurden alle Tiere gewogen. Bei 171 Schweinen der Gruppe V erfolgte in der 18. und 20. LW eine Messung der Hodengröße. Nach der Schlachtung wurden Schlachtkörpergewicht und weitere Schlachtparameter erhoben und mit Halsmuskelstücken aller Tiere Koch- und Bratproben durchgeführt. Ergebnisse: In der 22. LW differierte das Durchschnittsgewicht der Schweine beider Versuchsgruppen nicht signifikant (K = 89,4 kg; V = 88,6 kg), doch ergaben sich in Gruppe V im Mittel niedrigere Schlachtkörpergewichte sowie Muskel- und Speckdicken. Die mittleren Tageszunahmen (TGZ) in Gruppe V waren ab der 18. LW im Vergleich zur Gruppe K signifikant höher (V = 1121 g; K = 1007 g; p < 0,001), nicht jedoch im Zeitraum zwischen 12. und 18. LW (K = 740 g; V = 668 g; p < 0,001). Die Hoden der vakzinierten Tiere verkleinerten sich nach der zweiten Injektion signifikant. Koch- und Bratprobe von Muskelstücken aller Tiere waren negativ. Schlussfolgerung: Gegen Ebergeruch geimpfte Schweine zeigten vor der zweiten Impfung niedrigere TGZ als die chirurgisch kastrierten, glichen den Gewichtsunterschied jedoch nach der zweiten Impfung aus. Die Verkleinerung der Hoden nach der Vakzination kann als Impferfolg gewertet werden. Nach Applikation von Improvac® wurde an den Schlachtkörpern keine Geruchsabweichung festgestellt. Klinische Relevanz: Die Vakzination verhindert ebenso wie die chirurgische Kastration das Auftreten von Ebergeruch zuverlässig. Der nach der zweiten Impfung beobachtete Anstieg der TGZ lässt sich bei entsprechendem Management nutzen.

The efficacy of a discontinuous graded exercise test in measuring peak oxygen uptake in children aged 8 to 10 years

As children's natural activity patterns are highly intermittent in nature, and characterised by rapid changes from rest to vigorous physical activity, discontinuous exercise tests may be considered ecologically valid for this population group. This study compared the peak physiological responses from a discontinuous and continuous graded exercise test (GXT_D, GXT_C, respectively) during treadmill exercise in children. Twenty-one healthy children (9.6 ± 0.6 y) completed GXT_D and GXT_C in a randomised order, separated by 72-hours. Following each GXT, and after a 15-minute recovery, participants completed a verification test at 105% of the velocity attained at peak oxygen consumption (VO2peak). There were no differences in VO2peak (55.3 ± 8.2 cf. 54.4 ± 7.6 mL·kg-1·min-1) or maximal heart rate (202 ± 10 cf. 204 ± 8 b·min-1) between GXT_C and GXT_D, respectively (P>.05). Peak running speed (10.7 ± 0.9 cf. 12.1 ± 1.3 km·h-1) and respiratory exchange ratio (1.04 ± 0.05 cf. 0.92 ± 0.05) were however different between tests (P<.001). Although similar peak physiological values were revealed between GXT_C and the corresponding verification test (P>.05), VO2peak (53.3 ± 7.3 mL·kg-1·min-1) and heart rate (197 ± 13 b·min-1) were significantly lower in the GXT_D verification test (P<.05). In conclusion, a discontinuous GXT is an accurate measure of VO2peak in children aged 8 to 10 years and may be a valid alternative to a continuous GXT, despite its longer duration.

Publisher's Note: Isomer Shift and Magnetic Moment of the Long-Lived 1/2^{+} Isomer in _{30}^{79}Zn_{49}: Signature of Shape Coexistence near ^{78}Ni [Phys. Rev. Lett. 116, 182502 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.116.182502.

Isomer Shift and Magnetic Moment of the Long-Lived 1/2^{+} Isomer in _{30}^{79}Zn_{49}: Signature of Shape Coexistence near ^{78}Ni

Collinear laser spectroscopy is performed on the _{30}^{79}Zn_{49} isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life is confirmed, and the nuclear spins and moments of the ground and isomeric states in ^{79}Zn as well as the isomer shift are measured. From the observed hyperfine structures, spins I=9/2 and I=1/2 are firmly assigned to the ground and isomeric states. The magnetic moment μ (^{79}Zn)=-1.1866(10)μ_{N}, confirms the spin-parity 9/2^{+} with a νg_{9/2}^{-1} shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment μ (^{79m}Zn)=-1.0180(12)μ_{N} supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the N=50 shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state, δ⟨r_{c}^{2}⟩^{79,79m}=+0.204(6)  fm^{2}, providing first evidence of shape coexistence.

Neutralization of inhibitory antibodies and restoration of therapeutic ADAMTS-13 activity levels in inhibitor-treated rats by the use of defined doses of recombinant ADAMTS-13

BACKGROUND

Acquired thrombotic thrombocytopenic purpura (TTP) is caused by an autoantibody-mediated deficiency of the von Willebrand factor-cleaving protease ADAMTS-13. Acute episodes of the disease are treated with a combination of immunosuppression and repeated cycles of plasma exchange to remove anti-ADAMTS-13 autoantibodies and, at the same time, replenish functional ADAMTS-13. Although this is often effective, the mortality rate has remained between 10% and 20%, highlighting the need for safer treatment options.

OBJECTIVES

We previously showed that, in vitro, human recombinant ADAMTS-13 (rADAMTS-13) is able to override neutralizing antibodies and restore ADAMTS-13 activity in plasma from patients with acquired TTP. In the present study, we assessed the in vivo feasibility of this strategy by using a rat model.

METHODS

Wild-type rats were adjusted to an ADAMTS-13 inhibitor (inhibitor) titer of ~ 10 BU mL(-1) with goat anti-ADAMTS-13 IgG, and treated with increasing doses of rADAMTS-13. Blood samples were drawn and analyzed for ADAMTS-13-specific parameters, including FRETS-VWF73 activity, inhibitor, and ADAMTS-13-specific immune complexes (ICs). The pharmacokinetics of ADAMTS-13 activity and inhibitors were evaluated.

RESULTS

Administration of inhibitor titer-adjusted doses of rADAMTS-13 to inhibitor-treated rats predictably restored activity. Inhibitors were readily neutralized through formation of ADAMTS-13-specific ICs, which were cleared at a higher rate than the free inhibitor. Surplus protease was enzymatically active in plasma, and showed similar pharmacokinetics to ADAMTS-13 in not inhibitor-treated rats.

CONCLUSIONS

Defined doses of rADAMTS-13 neutralized circulating anti-ADAMTS-13 antibodies and enabled reconstitution of ADAMTS-13 activity in plasma in our model, indicating that the protease may be a promising candidate for further exploration in treating acute episodes of acquired TTP.

Volume perfusion computed tomography (VPCT)-based evaluation of response to TACE using two different sized drug eluting beads in patients with nonresectable hepatocellular carcinoma: Impact on tumor and liver parenchymal vascularisation

OBJECTIVE

Response monitoring of transarterial chemoembolization (TACE) with the help of volume perfusion computed tomography (VPCT) at day one post-TACE and analysis of TACE-impact on tumor and uninvolved liver parenchymal perfusion by using different particles sizes and epirubicin dose.

MATERIALS AND METHODS

Institutional review board approved this prospective study. VPCT was performed in the baseline, post-interventional (FU1; 24 h post-TACE) and at follow-up (FU2; median, 81 days) in 45 consecutive patients. 100-300 μm (n=17) and 300-500 μm (n=28) drug eluting beads (DEB) using an epirubicin dose of (<=25 vs. >25) were administered. VPCT was performed for 40-s using 80 kV, 100/120 mAs, 64×0.6 mm collimation, 26 consecutive measurements, IV injection (50 ml iodinated contrast), flow rate (5 ml/s). Blood flow (BF), blood volume (BV) and k-trans were registered as average and max values in the tumor. Arterial liver perfusion (ALP), portal-venous perfusion (PVP) and the hepatic perfusion index (HPI) were registered both in tumor and non-involved liver parenchyma. Response to TACE was classified by VPCT as complete (CR), partial (PR) or no response (NR).

RESULTS

A significant reduction of viable tumor tissue was found in all patients between baseline and FU1 (p<0.001) being independent on particle size and epirubicin dose (p>0.05). PPV/NPV/sensitivity/specificity of post-interventional VPCT (FU1) results for prediction of the mid-term tumor course (FU2) were 100%/70%/76%/100%. There was generally a significant increase of the ALP between baseline and FU1 in the liver parenchyma coupled by a significant subsequent decrease (normalization) of ALP and HPI between FU1 and FU2.

CONCLUSION

VPCT accurately measures impact of TACE on liver tumor and hepatic parenchymal perfusion. The former proved not to be significantly dependent on particle size and epirubicin dose. There was no persistent perfusion deficit in the liver after TACE.

An in-ear pulse wave velocity measurement system using heart sounds as time reference

Pulse wave measurements provide vital information in medical diagnosis. For this reason, a measurement system is developed for determining the transient time of the pulse wave between the heart and the ear. To detect pressure variations in the sealed ear canal, caused by the arriving pulse wave, an in-ear sensor is developed which uses heart sounds as time reference. Furthermore, for extracting the heart sounds from the pressure measurements and calculating the pulse wave transient time, a MATLAB-based algorithm is described. An embedded microcontroller based measurement board is presented, which realizes an interface between the sensor and the computer for signal processing.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9  h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300  GeV to ∼10  TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24}  cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4  TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

Live cell tracking of symmetry break in actin cytoskeleton triggered by abrupt changes in micromechanical environments

Stimulus responsive hydrogels and live cell imaging allow for the quantitative parameterization of symmetry breaking in remodelling actin cytoskeleton.

A high accuracy broadband measurement system for time resolved complex bioimpedance measurements

Bioimpedance measurements are useful tools in biomedical engineering and life science. Bioimpedance is the electrical impedance of living tissue and can be used in the analysis of various physiological parameters. Bioimpedance is commonly measured by injecting a small well known alternating current via surface electrodes into an object under test and measuring the resultant surface voltages. It is non-invasive, painless and has no known hazards. This work presents a field programmable gate array based high accuracy broadband bioimpedance measurement system for time resolved bioimpedance measurements. The system is able to measure magnitude and phase of complex impedances under test in a frequency range of about 10-500 kHz with excitation currents from 10 µA to 5 mA. The overall measurement uncertainties stay below 1% for the impedance magnitude and below 0.5° for the phase in most measurement ranges. Furthermore, the described system has a sample rate of up to 3840 impedance spectra per second. The performance of the bioimpedance measurement system is demonstrated with a resistor based system calibration and with measurements on biological samples.

Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.