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JAMA Oncology Mar 2023Magnetic resonance imaging (MRI) guidance offers multiple theoretical advantages in the context of stereotactic body radiotherapy (SBRT) for prostate cancer. However, to...
IMPORTANCE
Magnetic resonance imaging (MRI) guidance offers multiple theoretical advantages in the context of stereotactic body radiotherapy (SBRT) for prostate cancer. However, to our knowledge, these advantages have yet to be demonstrated in a randomized clinical trial.
OBJECTIVE
To determine whether aggressive margin reduction with MRI guidance significantly reduces acute grade 2 or greater genitourinary (GU) toxic effects after prostate SBRT compared with computed tomography (CT) guidance.
DESIGN, SETTING, AND PARTICIPANTS
This phase 3 randomized clinical trial (MRI-Guided Stereotactic Body Radiotherapy for Prostate Cancer [MIRAGE]) enrolled men aged 18 years or older who were receiving SBRT for clinically localized prostate adenocarcinoma at a single center between May 5, 2020, and October 1, 2021. Data were analyzed from January 15, 2021, through May 15, 2022. All patients had 3 months or more of follow-up.
INTERVENTIONS
Patients were randomized 1:1 to SBRT with CT guidance (control arm) or MRI guidance. Planning margins of 4 mm (CT arm) and 2 mm (MRI arm) were used to deliver 40 Gy in 5 fractions.
MAIN OUTCOMES AND MEASURES
The primary end point was the incidence of acute (≤90 days after SBRT) grade 2 or greater GU toxic effects (using Common Terminology Criteria for Adverse Events, version 4.03 [CTCAE v4.03]). Secondary outcomes included CTCAE v4.03-based gastrointestinal toxic effects and International Prostate Symptom Score (IPSS)-based and Expanded Prostate Cancer Index Composite-26 (EPIC-26)-based outcomes.
RESULTS
Between May 2020 and October 2021, 156 patients were randomized: 77 to CT (median age, 71 years [IQR, 67-77 years]) and 79 to MRI (median age, 71 years [IQR, 68-75 years]). A prespecified interim futility analysis conducted after 100 patients reached 90 or more days after SBRT was performed October 1, 2021, with the sample size reestimated to 154 patients. Thus, the trial was closed to accrual early. The incidence of acute grade 2 or greater GU toxic effects was significantly lower with MRI vs CT guidance (24.4% [95% CI, 15.4%-35.4%] vs 43.4% [95% CI, 32.1%-55.3%]; P = .01), as was the incidence of acute grade 2 or greater gastrointestinal toxic effects (0.0% [95% CI, 0.0%-4.6%] vs 10.5% [95% CI, 4.7%-19.7%]; P = .003). Magnetic resonance imaging guidance was associated with a significantly smaller percentage of patients with a 15-point or greater increase in IPSS at 1 month (6.8% [5 of 72] vs 19.4% [14 of 74]; P = .01) and a significantly reduced percentage of patients with a clinically significant (≥12-point) decrease in EPIC-26 bowel scores (25.0% [17 of 68] vs 50.0% [34 of 68]; P = .001) at 1 month.
CONCLUSIONS AND RELEVANCE
In this randomized clinical trial, compared with CT-guidance, MRI-guided SBRT significantly reduced both moderate acute physician-scored toxic effects and decrements in patient-reported quality of life. Longer-term follow-up will confirm whether these notable benefits persist.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT04384770.
Topics: Male; Humans; Aged; Prostate; Radiosurgery; Quality of Life; Optical Illusions; Prostatic Neoplasms; Magnetic Resonance Imaging; Tomography, X-Ray Computed
PubMed: 36633877
DOI: 10.1001/jamaoncol.2022.6558 -
Perception Sep 2023A novel geometrical optical illusion is reported in this article: the horizontal distances of the contextual structures distort the perceived vertical positions of...
A novel geometrical optical illusion is reported in this article: the horizontal distances of the contextual structures distort the perceived vertical positions of observed objects. Specifically, the illusion manifests in the form of connected boxes of varying widths but equal heights, each containing a circle at the center. Despite identical vertical positioning of the circles, they appear misaligned. The illusion diminishes when the boxes are removed. Potential underlying mechanisms are discussed.
Topics: Humans; Orientation; Optical Illusions
PubMed: 37427447
DOI: 10.1177/03010066231186557 -
Journal of Clinical Imaging Science 2021We describe a radiological sign, "inside-outside sign," observed during the cannulation of an expandable contrast-filled tubular structure in the human body. In this...
We describe a radiological sign, "inside-outside sign," observed during the cannulation of an expandable contrast-filled tubular structure in the human body. In this optical illusion, a catheter or guidewire appears to be outside the lumen when it is inside the lumen in reality. Knowing this rare optical illusion is essential to avoid mistaking it for a catheter or guidewire outside the lumen.
PubMed: 34754597
DOI: 10.25259/JCIS_192_2021 -
Journal of Vision Aug 2020We recently found only weak correlations between the susceptibility to various visual illusions. However, we observed strong correlations among different variants of an...
We recently found only weak correlations between the susceptibility to various visual illusions. However, we observed strong correlations among different variants of an illusion, suggesting that the visual space of illusions includes several illusion-specific factors. Here, we specifically examined how factors for the vertical-horizontal, Müller-Lyer, and Ponzo illusions relate to each other. We measured the susceptibility to each illusion separately and to combinations of two illusions, which we refer to as a merged illusion; for example, we tested the Müller-Lyer illusion and the vertical-horizontal illusion, as well as a merged version of both illusions. We used an adjustment procedure in two experiments with 306 and 98 participants, respectively. Using path analyses, correlations, and exploratory factor analyses, we found that the susceptibility to a merged illusion is well predicted from the susceptibilities to the individual illusions. We suggest that there are illusion-specific factors that, by independent combinations, represent the whole visual structure underlying illusions.
Topics: Adult; Female; Humans; Illusions; Male; Optical Illusions; Visual Perception; Young Adult
PubMed: 32766743
DOI: 10.1167/jov.20.8.12 -
Journal of Comparative Psychology... Nov 2019Researchers and artists have long been interested in visual illusions because they illustrate the interesting, complicated, and constrained ways in which we perceive the...
Researchers and artists have long been interested in visual illusions because they illustrate the interesting, complicated, and constrained ways in which we perceive the world. Although we may not be familiar with the names of the many different visual illusions that exist (e.g., the Necker cube, the Müller-Lyer illusion, and the Hermann grid illusion, to name a few), people with typically functioning will certainly have seen many of these. We have known for centuries that humans perceive these illusions. We have known for the past few decades that nonhuman mammals can perceive these illusions, and very recent work has revealed that birds and fish perceive some of these illusions, though sometimes in a way opposite to how our own species does. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Topics: Animals; Humans; Optical Illusions
PubMed: 31647270
DOI: 10.1037/com0000204 -
Perception Jul 2022In order to investigate interrelations between the Oppel-Kundt- and the T-illusion, T-type figures, comprised of one dotted and one empty line (demarcated by its...
In order to investigate interrelations between the Oppel-Kundt- and the T-illusion, T-type figures, comprised of one dotted and one empty line (demarcated by its endpoints), separated by a gap of variable size, and rotated to oblique orientations, were judged with regard to the lengths of the two extents. The T-illusion (overestimation of the length of the undivided line) was greater for a T with a dotted undivided line and a small gap. When the divided line was dotted, the illusion vanished at a small gap and reversed at a larger one. Findings are interpreted to mirror activities of a neural T-schema as well as orientation- and density-sensitive neurons.
Topics: Humans; Illusions; Optical Illusions
PubMed: 35570743
DOI: 10.1177/03010066221096998 -
Perception Apr 2022Ambiguous figures (aka bistable, multistable, or reversible images) have fascinated scientists as well as laypersons for centuries. It may be surprising indeed how one...
Ambiguous figures (aka bistable, multistable, or reversible images) have fascinated scientists as well as laypersons for centuries. It may be surprising indeed how one and the same physical depiction can be experienced in perceptual awareness in cardinally different ways. In the most well-known examples of such illusions of multistability, the phenomenal change relates just to organization. Much less common are perceptions of alternating content in the ambiguous visual image. Here, I introduce one such example.
Topics: Humans; Illusions; Optical Illusions
PubMed: 35285746
DOI: 10.1177/03010066221086080 -
Schizophrenia Research Feb 2023Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the... (Review)
Review
Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the assumption of abnormal illusion perception in patients and, therefore, the validity of this approach. Here, we present a systematic review of the current evidence regarding visual illusion perception abnormalities in patients with schizophrenia. Relevant publications were identified by a systematic search of PubMed, Literatura LILACS, PsycINFO, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), IBECS, BIOSIS, and Web of Science. Forty-five studies were selected which included illusions classified as 'Motion illusions', 'Geometric-optical illusions', 'Illusory contours', 'Depth inversion illusion', and 'Non-specific'. There is concordant evidence of abnormal processing of illusions in patients for most categories, especially in facial Depth Inversion and Müller-Lyer illusions. There were significant methodological disparities and shortcomings, but risk of bias was overall low for individual studies. The usefulness of visual illusions as tools in clinical settings as well as in basic research may be contingent on significant methodological refinements.
Topics: Humans; Illusions; Schizophrenia; Optical Illusions; Form Perception; Visual Perception
PubMed: 36610221
DOI: 10.1016/j.schres.2022.12.030 -
Current Biology : CB Dec 2023Contributions of the inner retinal photopigment melanopsin to human visual perception are incompletely understood. Here, we use a four-primary display to produce stimuli...
Contributions of the inner retinal photopigment melanopsin to human visual perception are incompletely understood. Here, we use a four-primary display to produce stimuli differing in melanopsin versus cone contrast in psychophysical paradigms in eight subjects with normal color vision. We address two predictions from electrophysiological recordings of the melanopsin system in non-human mammals: melanopsin influences color and/or supports image persistence under visual fixation. We first construct chromatic contrast sensitivity contours for stimuli differing in melanopsin excitation presented as a central annulus (10°) or peripheral (22.5°) spot. We find that although including melanopsin contrast produces modest changes in the average chromatic coordinates in both eccentricities, this occurs equally at low (0.5 Hz) and higher (3.75 Hz) temporal frequencies, arguing that it reflects divergence in cone spectral sensitivity in our participants from that captured in standardized cone fundamentals rather than a melanopsin contribution to color. We continue to ask whether the established ability of melanopsin to sustain firing of visual neurons under extended light exposure has a visual correlate, using the optical illusion of Troxler fading in which blurred spots in periphery disappear during visual fixation. We find that introducing additional melanopsin contrast (+28% Michelson contrast) to either bright or dark spots increases fading latency by 35% ± 8.8% and 41% ± 13.6%, respectively. Our data argue that the primary contribution of melanopsin to perception under these conditions is not to provide a color percept but rather to enhance persistence of low spatial frequency patterns during visual fixation.
Topics: Animals; Humans; Photic Stimulation; Retina; Retinal Cone Photoreceptor Cells; Vision, Ocular; Rod Opsins; Mammals
PubMed: 37967553
DOI: 10.1016/j.cub.2023.10.039 -
The Journal of Comparative Neurology Dec 2020This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species.... (Review)
Review
This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species. Multistable perception is characterized by two or more perceptual interpretations spontaneously alternating, or rivaling, when animals are exposed to stimuli with inherent sensory ambiguity. There is a wide array of ambiguous stimuli across sensory modalities, ranging from the configural changes observed in simple line drawings, such as the famous Necker cube, to the alternating perception of entire visual scenes that can be instigated by interocular conflict. The latter phenomenon, called binocular rivalry, in particular caught the attention of the late Jack Pettigrew, who combined his interest in the neuronal basis of perception with a unique comparative biological approach that considered ambiguous sensation as a fundamental problem of sensory systems that has shaped the brain throughout evolution. Here, we examine the research findings on visual perceptual alternation and suppression in a wide variety of species including insects, fish, reptiles, and primates. We highlight several interesting commonalities across species and behavioral indicators of perceptual alternation. In addition, we show how the comparative approach provides new avenues for understanding how the brain suppresses opposing sensory signals and generates alternations in perceptual dominance.
Topics: Animals; Attention; Humans; Optical Illusions; Photic Stimulation; Psychomotor Performance; Species Specificity; Visual Perception
PubMed: 32361986
DOI: 10.1002/cne.24939