Anatomical models are important training and teaching tools in the clinical environment and are routinely used in medical imaging research. Advances in segmentation algorithms and increased ...availability of three-dimensional (3D) printers have made it possible to create cost-efficient patient-specific models without expert knowledge. We introduce a general workflow that can be used to convert volumetric medical imaging data (as generated by Computer Tomography (CT)) to 3D printed physical models. This process is broken up into three steps: image segmentation, mesh refinement and 3D printing. To lower the barrier to entry and provide the best options when aiming to 3D print an anatomical model from medical images, we provide an overview of relevant free and open-source image segmentation tools as well as 3D printing technologies. We demonstrate the utility of this streamlined workflow by creating models of ribs, liver, and lung using a Fused Deposition Modelling 3D printer.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This review identifies and examines terms used to describe a radiological research “study” or “trial”. A taxonomy of clinical research descriptions is explained with reference to medical imaging ...examples. Because many descriptive terms have precise methodological implications, it is important that these terms are understood by readers and used correctly by researchers, so that the reader is not misled.
Key Points
• Multiple different terms are being used to describe radiological research “studies” and “trials”, and many of these terms have precise methodological implications.
• Radiological researchers sometimes use titles that describe their research incorrectly. This can mislead the reader as to what was actually done.
• It is important that readers and researchers understand the correct taxonomy of clinical research and that researchers adopt the correct description for their work.
Objective
Radiological findings in solitary rectal ulcer syndrome (SRUS) are well described for evacuation proctography (EP) but sparse for magnetic resonance defecography (MRD). In order to rectify ...this, we describe the spectrum of MRD findings in patients with histologically proven SRUS.
Materials and methods
MRD from twenty-eight patients (18 female; 10 males) with histologically confirmed SRUS were identified. MRD employed a 1.5-T magnet and a standardized technique with the rectal lumen filled with gel and imaged sagittally in the supine position, before, during, and after attempted rectal evacuation. A single radiologist observer with 5 years’ experience in pelvic floor imaging made the anatomical and functional measurements.
Results
Sixteen patients (10 female) demonstrated internal rectal intussusception and 3 patients (11%) demonstrated complete external rectal prolapse. Anterior rectoceles were noted in 12 female patients (43%). Associated anterior and middle compartment weakness (evidenced by excessive descent) was observed in 18 patients (64%). Cystocele was found in 14 patients (50%) and uterine prolapse was noted in 7 patients (25%). Enterocoeles were detected in 5 patients (18%) and peritoneocoele in 5 patients (18%). None had sigmoidocoele. Sixteen patients (57%) demonstrated delayed voiding and 13 patients (46%) incomplete voiding, suggesting defecatory dyssynergia.
Conclusion
MRD can identify and grade both rectal intussusception and dyssynergia in SRUS, and also depict associated anterior and/or middle compartment descent. Distinction between structural and functional findings has important therapeutic implications.
Key Points
MRD can identify and grade both rectal intussusception and dyssynergia in patients with SRUS.
MRD is an acceptable substitute to evacuation proctography in assessing anorectal dysfunctions when attempting to avoid ionizing radiation.
SRUS influences the pelvic floor globally. MRD depicts associated anterior and/or middle compartment prolapse.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Purpose
To determine if a new photoacoustic imaging (PAI) system successfully depicts (1) peripheral arteries and (2) microvascular circulatory changes in response to thermal stimuli.
Methods
...Following ethical permission, 8 consenting subjects underwent PAI of the dorsalis pedis (DP) artery, and 13 completed PAI of the index fingertip. Finger images were obtained after immersion in warm (30-35 °C) or cold (10-15 °C) water to promote vasodilation or vasoconstriction. The PAI instrument used a Fabry-Perot interferometeric ultrasound sensor and a 30-Hz 750-nm pulsed excitation laser. Volumetric images were acquired through a 14 × 14 × 14-mm volume over 90 s. Images were evaluated subjectively and quantitatively to determine if PAI could depict cold-induced vasoconstriction. The full width at half maximum (FWHM) of resolvable vessels was measured.
Results
Fingertip vessels were visible in all participants, with mean FWHM of 125 μm. Two radiologists used PAI to correctly identify vasoconstricted fingertip capillary beds with 100% accuracy (95% CI 77.2-100.0%,
p
< 0.001). The number of voxels exhibiting vascular signal was significantly smaller after cold water immersion (cold: 5263 voxels; warm: 363,470 voxels,
p
< 0.001). The DP artery was visible in 7/8 participants (87.5%).
Conclusion
PAI achieves rapid, volumetric, high-resolution imaging of peripheral limb vessels and the microvasculature and is responsive to vasomotor changes induced by thermal stimuli.
Key points
•
Fabry-Perot interferometer-based photoacoustic imaging (PAI) generates volumetric, high-resolution images of the peripheral vasculature.
•
The system reliably detects thermally induced peripheral vasoconstriction (100% correct identification rate, p < 0.001).
•
Vessels measuring less than 100 μm in diameter can be depicted in vivo.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
These consensus guidelines were jointly commissioned by the British Society of Gastroenterology (BSG), the Association of Coloproctology of Great Britain and Ireland (ACPGBI) and Public Health ...England (PHE). They provide an evidence-based framework for the use of surveillance colonoscopy and non-colonoscopic colorectal imaging in people aged 18 years and over. They are the first guidelines that take into account the introduction of national bowel cancer screening. For the first time, they also incorporate surveillance of patients following resection of either adenomatous or serrated polyps and also post-colorectal cancer resection. They are primarily aimed at healthcare professionals, and aim to address:Which patients should commence surveillance post-polypectomy and post-cancer resection?What is the appropriate surveillance interval?When can surveillance be stopped? two or more premalignant polyps including at least one advanced colorectal polyp (defined as a serrated polyp of at least 10 mm in size or containing any grade of dysplasia, or an adenoma of at least 10 mm in size or containing high-grade dysplasia);
five or more premalignant polyps The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument provided a methodological framework for the guidelines. The BSG's guideline development process was used, which is National Institute for Health and Care Excellence (NICE) compliant.two or more premalignant polyps including at least one advanced colorectal polyp (defined as a serrated polyp of at least 10 mm in size or containing any grade of dysplasia, or an adenoma of at least 10 mm in size or containing high-grade dysplasia);
five or more premalignant polyps The key recommendations are that the high-risk criteria for future colorectal cancer (CRC) following polypectomy comprise
:two or more premalignant polyps including at least one advanced colorectal polyp (defined as a serrated polyp of at least 10 mm in size or containing any grade of dysplasia, or an adenoma of at least 10 mm in size or containing high-grade dysplasia);
five or more premalignant polyps This cohort should undergo a one-off surveillance colonoscopy at 3 years. Post-CRC resection patients should undergo a 1 year clearance colonoscopy, then a surveillance colonoscopy after 3 more years.
Terminal digit preference bias for "pleasing" numbers has been described in many areas of medicine. The aim of this study was to determine whether endoscopists, radiologists, and pathologists exhibit ...such bias when measuring colorectal polyp diameters.
Colorectal polyp diameters measured at endoscopy, computed tomographic colonography (CTC), and histopathology were collated from a colorectal cancer screening program and two parallel multicenter randomized trials. Smoothing models were fitted to the data to estimate the expected number of polyps at 1-mm increments, assuming no systematic measurement bias. The difference between the expected and observed numbers of polyps was calculated for each terminal digit using statistical modeling. The impact of measurement bias on per-patient detection rates of polyps ≥ 10 mm was estimated for each modality.
A total of 92 124 individual polyps were measured by endoscopy (91 670 screening and 454 from trials), 2385 polyps were measured by CTC (1664 screening, 721 trials), and 79 272 were measured by histopathology (78 783 screening, 489 trials). Clustering of polyp diameter measurements at 5-mm intervals was demonstrated for all modalities, both in the screening program and the trials. The statistical models estimated that per-patient detection rates of polyps ≥ 10 mm were over-inflated by 2.4 % for endoscopy, 3.1 % for CTC, and 3.3 % for histopathology in the screening program, with similar trends in the randomized trials.
Endoscopists, radiologists, and pathologists all exhibit terminal digit preference when measuring colorectal polyps. This will bias trial data, referral rates for further testing, adenoma surveillance regimens, and comparisons between tests.
Colonoscopy examination does not always detect colorectal cancer (CRC)— some patients develop CRC after negative findings from an examination. When this occurs before the next recommended ...examination, it is called interval cancer. From a colonoscopy quality assurance perspective, that term is too restrictive, so the term post-colonoscopy colorectal cancer (PCCRC) was created in 2010. However, PCCRC definitions and methods for calculating rates vary among studies, making it impossible to compare results. We aimed to standardize the terminology, identification, analysis, and reporting of PCCRCs and CRCs detected after other whole-colon imaging evaluations (post-imaging colorectal cancers PICRCs).
A 20-member international team of gastroenterologists, pathologists, and epidemiologists; a radiologist; and a non-medical professional met to formulate a series of recommendations, standardize definitions and categories (to align with interval cancer terminology), develop an algorithm to determine most-plausible etiologies, and develop standardized methodology to calculate rates of PCCRC and PICRC. The team followed the Appraisal of Guidelines for Research and Evaluation II tool. A literature review provided 401 articles to support proposed statements; evidence was rated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The statements were voted on anonymously by team members, using a modified Delphi approach.
The team produced 21 statements that provide comprehensive guidance on PCCRCs and PICRCs. The statements present standardized definitions and terms, as well as methods for qualitative review, determination of etiology, calculation of PCCRC rates, and non-colonoscopic imaging of the colon.
A 20-member international team has provided standardized methods for analysis of etiologies of PCCRCs and PICRCs and defines its use as a quality indicator. The team provides recommendations for clinicians, organizations, researchers, policy makers, and patients.
To assess the repeatability in human volunteers of software-quantified small bowel motility captured with magnetic resonance (MR) imaging and to test the ability to detect changes in motility induced ...by pharmacologic agents.
The study was approved by the Royal Free Research Ethics Committee, and all subjects gave full written informed consent. Twenty-one healthy volunteers (14 men, seven women; mean age, 28 years) underwent cine MR imaging with a three-dimensional balanced turbo field-echo sequence to capture small bowel motility. Volume blocks (15 cm thick) were acquired every second during a 20-second breath hold. A randomized, blinded, placebo-controlled crossover study of either 0.5 mg neostigmine or saline (n = 11) or 20 mg intravenous butylscopolamine or saline (n = 10) was performed with motility MR imaging at baseline and repeated at a mean of 4 weeks (range, 2-7 weeks). Two readers independently drew regions of interest around the small bowel, and motility was quantified by using a registration algorithm that provided a global motility metric in arbitrary units. Repeatability of the motility measurements at baseline was assessed by using Bland-Altman and within-subject coefficient of variation measures. Changes in mean motility measurements after drug administration were compared with those after placebo administration by using paired t testing.
The repeatability between baseline measurements of motility was high; the Bland-Altman mean difference was -0.0025 (range, 0.28-0.4), the 95% limit of agreement was ±0.044 arbitrary units (au), and the within-subject coefficient of variation was 4.9%. Measured motility with neostigmine (mean, 0.39 au) was significantly higher than that with placebo (mean, 0.34 au; P < .001), whereas that with butylscopolamine (mean, 0.13 au) was significantly lower than that with placebo (mean, 0.30 au; P < .001).
Quantification of small bowel motility with use of MR imaging in healthy volunteers is repeatable and sensitive to changes induced by means of pharmacologic manipulation.
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13130151/-/DC1.
Background
Timed barium swallow (TBS) is a recommended ancillary investigation in evaluation of esophagogastric junction (EGJ) obstruction, yet there are little data comparing esophageal stasis ...across subtypes.
Methods
A retrospective cohort study was performed. All type III achalasia diagnosed between November 2016 and November 2020 were included, along with matched numbers of consecutive types I and II and conclusive EGJOO cases with concurrent TBS evaluation. Co‐primary outcomes were TBS retention at 1 and 5 min. Secondary outcomes were symptoms and manometric metrics of EGJ function and peristaltic integrity.
Key Results
One hundred patients were included (25 each of types I‐III and conclusive EGJOO). TBS retention measured by height and width at 1 and 5 min differed significantly across the four subtypes (p < 0.0001 all comparisons), with esophageal stasis tending to be significantly greater for types I and II achalasia (88% and 84% with >5 cm column at 5 min) compared to type III and EGJOO (24% and 8% with >5 cm column; p < 0.0001). Eckardt symptom severity was similar across subtypes (p = 0.30). Magnitude of esophageal stasis and integrated relaxation pressure (IRP) were uncorrelated (R = 0.21). In EGJOO, the number of swallows with intact peristalsis inversely correlated with barium column height (R = −0.49) and those with disordered peristalsis were more likely to have any residual barium at 5 min compared to those without disordered peristalsis (43% vs. 0%; p = 0.02).
Conclusions & Inferences
Timed barium swallow findings differed markedly with significantly less esophageal stasis in type III achalasia and EGJOO, despite similar symptom severity and no correlation between degree of emptying and IRP. Preservation of peristalsis may underlie this finding in EGJOO.
The amount of barium retention on timed barium swallow is significantly less in Type III achalasia and conclusive EGJOO, compared to Types I and II achalasia.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Many systematic reviews and meta-analyses concern the effect of a healthcare intervention on a binary outcome
. occurrence (or not) of a particular event. Usually, the overall effect, pooled across ...all studies included in the meta-analysis, is summarised using the odds ratio (OR) or the relative risk (RR). Under most circumstances, it is obvious how to identify what should be considered as the event of interest-for example, death or a clinically important side-effect. However, on occasion it may not be clear in which "direction" the event should be specified-such as attendance (
non-attendance) at cancer screening. Usually, this choice is not critical to the overall conclusion of the meta-analysis, but occasionally it can lead to differences in how the included studies are pooled, ultimately affecting the overall meta-analytic result, particularly when using RRs rather than ORs. In this commentary, we will explain this phenomenon in more detail using examples from the literature, and explore how analysts and readers can avoid some potential pitfalls.
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