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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 -
Experimental Psychology Nov 2018Recent research has shown that perceptual processes carry intrinsic affect. But prior studies have only manipulated the occurrence of perceptual processes by presenting...
Recent research has shown that perceptual processes carry intrinsic affect. But prior studies have only manipulated the occurrence of perceptual processes by presenting two different stimulus categories. The present studies go beyond this by manipulating perceptual expectations for identical stimuli. Seven experiments demonstrated that objectively identical stimuli become visually disappointing and are liked less when they violate the expectation that an intrinsically pleasant perceptual process will occur compared to when there is no perceptual expectation. These effects were specific to violations of perceptual expectations. By using between-subjects designs, participants' insight into the experimental manipulation was prevented. In combination with the use of identical stimuli across conditions, this provides the most stringent test of the idea that perception is intrinsically (un-)pleasant yet. The results are related to predictive coding frameworks and provide an explanation for why people sometimes enjoy additional perceptual effort.
Topics: Adult; Female; Humans; Illusions; Male; Visual Perception
PubMed: 30638171
DOI: 10.1027/1618-3169/a000419 -
Perception 2015
Topics: Depth Perception; Humans; Optic Flow; Optical Illusions; Photic Stimulation; Vision Disparity
PubMed: 26422897
DOI: 10.1068/p4405ed -
Acta Neurobiologiae Experimentalis 2019Perceptual estimates of spatial dimensions of visual objects depend on their shape and surface attributes. The present psychophysical study emphasizes two main...
Perceptual estimates of spatial dimensions of visual objects depend on their shape and surface attributes. The present psychophysical study emphasizes two main contributors to the Oppel‑Kundt illusion: the outline of the filled space and the mode of filling. In past experiments, both factors have been considered significant. Our experiments were performed by using combined stimuli of the Oppel‑Kundt figures and supplementary objects situated within the empty intervals of the figures. Line segments, empty and filled rectangles, blurred contours, and grey and color images were used for the supplementary stimuli role. The experimental data demonstrated an innate property of the objects to balance the illusion of distance if they were placed within the Oppel‑Kundt figure and to create an illusion of extent when compared with an empty space interval. Both the balance magnitude and the induced illusion strength varied depending on the objects' spatial structure. The supplementary objects showed a tendency to differ from each other by their functional capacity and were ranked from lowest to highest: a line segment, a solid bar with a blurred outline, a contour of a rectangle, a solid fill rectangle, greyscale patterns, and color pictures. The experimental findings provided support for an explanation of the Oppel‑Kundt illusion in terms of the spatial‑temporal summation of excitations representing the object outline and surface attributes at the lower cortical levels of the visual system. Along with the facts already established in current literature, the experimental data gave rise to the assumption that any visual object could appear larger than its occupied area, and that the Oppel‑Kundt illusion could become a separate case in the common sensory phenomenon of object size illusion.
Topics: Adult; Female; Form Perception; Humans; Male; Middle Aged; Optical Illusions; Photic Stimulation; Size Perception; Space Perception; Young Adult
PubMed: 31885396
DOI: No ID Found -
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 -
I-Perception 2018Past research has used the phi phenomenon to create the illusion of one object moving through another. This article presents three optical illusions that are...
Past research has used the phi phenomenon to create the illusion of one object moving through another. This article presents three optical illusions that are conceptually similar, yet little known within academic psychology. Two of the illusions have been developed within the magic community and involve the performer appearing to make a finger jump from one hand to another and a cup penetrate through another cup. The article explores the factors underpinning these illusions and describes how these factors were used to enhance a similar illusion developed outside of magic (the penetration of one hand through another).
PubMed: 30627414
DOI: 10.1177/2041669518816106 -
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 -
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