Standard Scan Research Articles

Microsurgical clipping of middle cerebral artery aneurysms: preoperative planning using virtual reality to reduce procedure time

The authors sought to evaluate the impact of virtual reality (VR) applications for preoperative planning and rehearsal on the total procedure time of microsurgical clipping of middle cerebral artery (MCA) ruptured and unruptured aneurysms compared with standard surgical planning. A retrospective review of 21 patients from 2016 to 2019 was conducted to determine the impact on the procedure time of MCA aneurysm clipping after implementing VR for preoperative planning and rehearsal. The control group consisted of patients whose procedures were planned with standard CTA and DSA scans (n = 11). The VR group consisted of patients whose procedures were planned with a patient-specific 360° VR (360VR) model (n = 10). The 360VR model was rendered using CTA and DSA data when available. Each patient was analyzed and scored with a case complexity (CC) 5-point grading scale accounting for aneurysm size, incorporation of M2 branches, and aspect ratio, with 1 being the least complex and 5 being the most complex. The mean procedure times were compared between the VR group and the control group, as were the mean CC score between the groups. Comorbidities and aneurysm conduction (ruptured vs unruptured) were also taken into consideration for the comparison. The mean CC scores for the control group and VR group were 2.45 ± 1.13 and 2.30 ± 0.48, respectively. CC was not significantly different between the two groups (p = 0.69). The mean procedure time was significantly lower for the VR group compared with the control group (247.80 minutes vs 328.27 minutes; p = 0.0115), particularly for the patients with a CC score of 2 (95% CI, p = 0.0064). A Charlson Comorbidity Index score was also calculated for each group, but no statistical significance was found (VR group, 2.8 vs control group, 1.8, p = 0.14). In this study, usage of 360VR models for planning the craniotomy and rehearsing with various clip sizes and configurations resulted in an 80-minute decrease in procedure time. These findings have suggested the potential of VR technology in improving surgical efficiency for aneurysm clipping procedures regardless of complexity, while making the procedure faster and safer.

Evaluation of the accuracy of E-FAST ultrasound in blunt trauma patients referred to the Emergency Department

Introduction: Trauma is one of the most common causes of death in the world. E-Fast ultrasound can detect the haemoperitoneum, intravenous pneumothorax, and hemothorax. In this study, we evaluated the accuracy of E-FAST focused ultrasound in blunt trauma patients referred to the Emergency Department. Methods: In this study 167 blunt trauma patients were included. E-FAST is performed from four standard spaces in terms of free fluid, chest in terms of hemothorax, and pneumothorax. Ultrasound is performed on the trauma patient and the obtained results were compared with the result of the standard gold CT scan test. All patient information including age, sex, mechanism of trauma, patient ISS, E-FAST result, and CT scan result were registered. Results: Overall, 174 patients were included that 45 (25.9%) of them were females. The mean age of the patients was 38.39±12.31 years. E-FAST had a sensitivity of 66.7 and a specificity of 100% in the diagnosis of hemothorax. Also, a positive predictive value of 100% and a negative predictive value of 99.4% were detected for 120 people in both normal tests. Conclusion: The results show E-FAST is a suitable alternative to CT scan in the diagnosis of hemothorax, pneumothorax, and free fluid in the abdomen, vulva, and pericardial cavity. Due to portability, safe body, no need for contrast, fast performance, as well as cheapness, and reproducibility, it will be a great help in diagnosing trauma-related lesions and prompt and timely treatment. CT scan should be used only in limited cases and special indications.

A Hybrid Scan Gibbs Sampler for Bayesian Models with Latent Variables

Gibbs sampling is a widely popular Markov chain Monte Carlo algorithm that can be used to analyze intractable posterior distributions associated with Bayesian hierarchical models. There are two standard versions of the Gibbs sampler: The systematic scan (SS) version, where all variables are updated at each iteration, and the random scan (RS) version, where a single, randomly selected variable is updated at each iteration. The literature comparing the theoretical properties of SS and RS Gibbs samplers is reviewed, and an alternative hybrid scan Gibbs sampler is introduced, which is particularly well suited to Bayesian models with latent variables. The word “hybrid” reflects the fact that the scan used within this algorithm has both systematic and random elements. Indeed, at each iteration, one updates the entire set of latent variables, along with a randomly chosen block of the remaining variables. The hybrid scan (HS) Gibbs sampler has important advantages over the two standard scan Gibbs samplers. First, the HS algorithm is often easier to analyze from a theoretical standpoint. In particular, it can be much easier to establish the geometric ergodicity of a HS Gibbs Markov chain than to do the same for the corresponding SS and RS versions. Second, the sandwich methodology developed in (Ann. Statist. 36 (2008) 532–554), which is also reviewed, can be applied to the HS Gibbs algorithm (but not to the standard scan Gibbs samplers). It is shown that, under weak regularity conditions, adding sandwich steps to the HS Gibbs sampler always results in a theoretically superior algorithm. Three specific Bayesian hierarchical models of varying complexity are used to illustrate the results. One is a simple location-scale model for data from the Student’s t distribution, which is used as a pedagogical tool. The other two are sophisticated, yet practical Bayesian regression models.

The Association Between Different Trajectories of Low Back Pain and Degenerative Imaging Findings in Young Adult Participants Within The Raine Study.

Case-control study. Investigate the association between lumbar spine magnetic resonance imaging (MRI) findings and 5-year trajectories of low back pain (LBP) in young Australian adults. The association between lumbar spine imaging findings and LBP remains unclear due to important limitations of previous research, such as a lack of clearly defined LBP phenotypes and inadequate controlling for age, which may substantially affect the association. Seventy-eight "case" participants with a previously identified "consistent high disabling LBP" trajectory from age 17 to 22 years and 78 "control" participants from a trajectory with consistently low LBP over the same time period, matched for sex, body mass index, physical activity levels, and work physical demands, were identified from Gen2 Raine Study participants. At age 27, participants underwent a standardized lumbar MRI scan, from which 14 specific MRI phenotypes were identified. Primary analyses used unconditional logistic regression, adjusting for covariates used in the matching process, to investigate the relationship between presence of each imaging finding and being a case or control. Secondary analyses explored those relationships based on the number of spinal levels with each MRI finding. The odds for being a case compared with a control were higher in those with disc degeneration (Pfirrmann grade ≥ 3; OR = 3.21, 95% CI: 1.60-6.44; P = 0.001) or those with a herniation (OR = 1.90, 95% CI: 0.96-3.74; P - 0.065). We also found that the association became substantially stronger when either disc degeneration or herniation was present at two or more spinal levels (OR = 5.56, 95% CI: 1.97-15.70; P = 0.001, and OR = 5.85, 95% CI: 1.54-22.25; P = 0.009, respectively). The other investigated MRI findings were not associated with greater odds of being a case. Lumbar disc degeneration and herniation may be important contributors to disabling LBP in young adults. Further investigation of their potential prognostic and causal roles is indicated.Level of Evidence: 4.

Improving Interpretability in Machine Diagnosis: Detection of Geographic Atrophy in OCT Scans

PurposeManually identifying geographic atrophy (GA) presence and location on OCT volume scans can be challenging and time consuming. This study developed a deep learning model simultaneously (1) to perform automated detection of GA presence or absence from OCT volume scans and (2) to provide interpretability by demonstrating which regions of which B-scans show GA.DesignMed-XAI-Net, an interpretable deep learning model was developed to detect GA presence or absence from OCT volume scans using only volume scan labels, as well as to interpret the most relevant B-scans and B-scan regions.ParticipantsOne thousand two hundred eighty-four OCT volume scans (each containing 100 B-scans) from 311 participants, including 321 volumes with GA and 963 volumes without GA.MethodsMed-XAI-Net simulates the human diagnostic process by using a region-attention module to locate the most relevant region in each B-scan, followed by an image-attention module to select the most relevant B-scans for classifying GA presence or absence in each OCT volume scan. Med-XAI-Net was trained and tested (80% and 20% participants, respectively) using gold standard volume scan labels from human expert graders.Main Outcome MeasuresAccuracy, area under the receiver operating characteristic (ROC) curve, F1 score, sensitivity, and specificity.ResultsIn the detection of GA presence or absence, Med-XAI-Net obtained superior performance (91.5%, 93.5%, 82.3%, 82.8%, and 94.6% on accuracy, area under the ROC curve, F1 score, sensitivity, and specificity, respectively) to that of 2 other state-of-the-art deep learning methods. The performance of ophthalmologists grading only the 5 B-scans selected by Med-XAI-Net as most relevant (95.7%, 95.4%, 91.2%, and 100%, respectively) was almost identical to that of ophthalmologists grading all volume scans (96.0%, 95.7%, 91.8%, and 100%, respectively). Even grading only 1 region in 1 B-scan, the ophthalmologists demonstrated moderately high performance (89.0%, 87.4%, 77.6%, and 100%, respectively).ConclusionsDespite using ground truth labels during training at the volume scan level only, Med-XAI-Net was effective in locating GA in B-scans and selecting relevant B-scans within each volume scan for GA diagnosis. These results illustrate the strengths of Med-XAI-Net in interpreting which regions and B-scans contribute to GA detection in the volume scan.

Risk of missing colorectal cancer with a COVID-adapted diagnostic pathway using quantitative faecal immunochemical testing.

BackgroundCOVID-19 has brought an unprecedented challenge to healthcare services. The authors’ COVID-adapted pathway for suspected bowel cancer combines two quantitative faecal immunochemical tests (qFITs) with a standard CT scan with oral preparation (CT mini-prep). The aim of this study was to estimate the degree of risk mitigation and residual risk of undiagnosed colorectal cancer.MethodDecision-tree models were developed using a combination of data from the COVID-adapted pathway (April–May 2020), a local audit of qFIT for symptomatic patients performed since 2018, relevant data (prevalence of colorectal cancer and sensitivity and specificity of diagnostic tools) obtained from literature and a local cancer data set, and expert opinion for any missing data. The considered diagnostic scenarios included: single qFIT; two qFITs; single qFIT and CT mini-prep; two qFITs and CT mini-prep (enriched pathway). These were compared to the standard diagnostic pathway (colonoscopy or CT virtual colonoscopy (CTVC)).ResultsThe COVID-adapted pathway included 422 patients, whereas the audit of qFIT included more than 5000 patients. The risk of missing a colorectal cancer, if present, was estimated as high as 20.2 per cent with use of a single qFIT as a triage test. Using both a second qFIT and a CT mini-prep as add-on tests reduced the risk of missed cancer to 6.49 per cent. The trade-off was an increased rate of colonoscopy or CTVC, from 287 for a single qFIT to 418 for the double qFIT and CT mini-prep combination, per 1000 patients.ConclusionTriage using qFIT alone could lead to a high rate of missed cancers. This may be reduced using CT mini-prep as an add-on test for triage to colonoscopy or CTVC.

Complex 3D scan trajectories for industrial cone-beam computed tomography using a hexapod

Industrial x-ray computed tomography (CT) represents an established measurement technique in the field of nondestructive testing and dimensional metrology. However, the measurement accuracy is sometimes limited by measurement artifacts that cannot be avoided using a standard circular scan trajectory. This problem can be addressed with the aid of flexible 3D trajectories, but up to date, the application of these is mainly restricted to special CT devices using robot arms. In this paper, we present results using a hexapod as an additional positioning system in a commercial industrial CT scanner. In addition to the 360∘ rotation, task-specific tilting of the part during the scan is possible in this way. We used and adapted geometry calibration procedures based on a multi-sphere reference object to enable reconstruction with high accuracy. Using a demonstrator test fixture with high absorbing elements, we show that severe metal and truncation artifacts can be avoided for a region-of-interest scan. Furthermore, cone-beam artifacts, which are inherent to circular scan trajectories, can be reduced significantly. Using measurement objects that can be measured well with a circular trajectory, we found that applying a 3D trajectory leads to dimensional measurement deviations in the same range or even lower than those of a circular trajectory. This suggests that the pose repeatability of the hexapod is sufficient to perform complex scan paths without general loss of accuracy. The obtained results could be relevant for end users of conventional CT scanners, as upgrading existing devices is in principle possible. The presented investigations form the basis for the application of trajectory optimization algorithms.

Three-dimensional reconstruction of intervertebral disc based on magnetic resonance imaging in patients with acute low back pain.

The aim of the study is to evaluate the morphology of the intervertebral discs visible in the magnetic resonance image in patients with sudden severe low back pain (with or without radiation of pain to the lower limb). The second goal of the study is to perform a digital three-plane reconstruction of the intervertebral disc and to compare this technique with a standard magnetic resonance imaging test. Twenty-five patients, mean age 35.5 years, all with acute low back pain, were examined. We compared the 3D MR models with standard MRI scans by measuring seven MRI parameters. In patients with sudden, severe low back pain, with clinical symptoms suggesting an etiology within the intervertebral disc, changes in a standard MRI are found consisting of the presence of a hernia / protrusion of the intervertebral disc and lowering the height of the intervertebral disc - with lowering the disc height occurs to a greater extent in the rear section. The 3D reconstruction is a reliable 3D representation of the intervertebral disc and adjacent vertebral bodies.

Impact of PET Staging of Follicular Lymphoma on Treatment Outcomes and Prognosis

Impact of PET Staging of Follicular Lymphoma on Treatment Outcomes and Prognosis

Management of bone metastasis and cancer treatment-induced bone loss during the COVID-19 pandemic: An international perspective and recommendations

Optimum management of patients with cancer during the COVID-19 pandemic has proved extremely challenging. Patients, clinicians and hospital authorities have had to balance the risks to patients of attending hospital, many of whom are especially vulnerable, with the risks of delaying or modifying cancer treatment. Those whose care has been significantly impacted include patients suffering from the effects of cancer on bone, where delivering the usual standard of care for bone support has often not been possible and clinicians have been forced to seek alternative options for adequate management.At a virtual meeting of the Cancer and Bone Society in July 2020, an expert group shared experiences and solutions to this challenge, following which a questionnaire was sent internationally to the symposium’s participants, to explore the issues faced and solutions offered. 70 respondents, from 9 countries (majority USA, 39%, followed by UK, 19%) included 50 clinicians, spread across a diverse range of specialties (but with a high proportion, 64%, of medical oncologists) and 20 who classified themselves as non-clinical (solely lab-based). Spread of clinician specialty across tumour types was breast (65%), prostate (27%), followed by renal, myeloma and melanoma.Analysis showed that management of metastatic bone disease in all solid tumour types and myeloma, adjuvant bisphosphonate breast cancer therapy and cancer treatment induced bone loss, was substantially impacted. Respondents reported delays to routine CT scans (58%), standard bone scans (48%) and MRI scans (46%), though emergency scans were less affected. Delays in palliative radiotherapy for bone pain were reported by 31% of respondents with treatments often involving only a single dose without fractionation. Delays to, or cancellation of, prophylactic surgery for bone pain were reported by 35% of respondents. Access to treatments with intravenous bisphosphonates and subcutaneous denosumab was a major problem, mitigated by provision of drug administration at home or in a local clinic, reduced frequency of administration or switching to oral bisphosphonates taken at home. The questionnaire also revealed damaging delays or complete stopping of both clinical and laboratory research.In addition to an analysis of the questionnaire, this paper presents a rationale and recommendations for adaptation of the normal guidelines for protection of bone health during the pandemic.

A Novel Nodule Edge Sharpness Radiomic Biomarker Improves Performance of Lung-RADS for Distinguishing Adenocarcinomas from Granulomas on Non-Contrast CT Scans

Simple SummaryThe great majority of pulmonary nodules on screening CT scans are benign (95%). Due to inaccurate diagnoses of granulomas from adenocarcinomas on CT scans, many patients with benign nodules are subjected to unnecessary surgical procedures. The aim of this retrospective study is to evaluate the discriminability of a new radiomic feature, nodule edge/interface sharpness (NIS), for distinguishing lung adenocarcinomas from benign granulomas on non-contrast CT scans. Moreover, we aim to evaluate whether NIS can improve the performance of Lung-RADS, by reclassifying benign nodules that were initially assessed as suspicious. In a cohort of 352 patients with diagnostic non-contrast CT scans, NIS radiomics was able to classify nodules with an area under the receiver operating characteristic curve (ROC AUC) of 0.77, and when combined with intra-tumoral textural and shape features, classification performance increased to AUC of 0.84. Additionally, the NIS classifier correctly reclassified 46% of those lesions that were actually benign but deemed suspicious by Lung-RADS. Combining NIS with Lung-RADS has the potential to alter patient management by significantly decreasing unnecessary biopsies/follow up imaging.The aim of this study is to evaluate whether NIS radiomics can distinguish lung adenocarcinomas from granulomas on non-contrast CT scans, and also to improve the performance of Lung-RADS by reclassifying benign nodules that were initially assessed as suspicious. The screening or standard diagnostic non-contrast CT scans of 362 patients was divided into training (St, N = 145), validation (Sv, N = 145), and independent validation (Siv, N = 62) sets from different institutions. Nodules were identified and manually segmented on CT images by a radiologist. A series of 264 features relating to the edge sharpness transition from the inside to the outside of the nodule were extracted. The top 10 features were used to train a linear discriminant analysis (LDA) machine learning classifier on St. In conjunction with the LDA classifier, NIS radiomics classified nodules with an AUC of 0.82 ± 0.04, 0.77, and 0.71 respectively on St, Sv, and Siv. We evaluated the ability of the NIS classifier to determine the proportion of the patients in Sv that were identified initially as suspicious by Lung-RADS but were reclassified as benign by applying the NIS scores. The NIS classifier was able to correctly reclassify 46% of those lesions that were actually benign but deemed suspicious by Lung-RADS alone on Sv.

POS1394 ACCURACY AND PERFORMANCE OF A HANDHELD ULTRASOUND DEVICE TO ASSESS ARTICULAR AND PERIARTICULAR PATHOLOGIES IN PATIENTS WITH INFLAMMATORY ARTHRITIS

Background:Handheld ultrasound (HHUS) devices have increasingly found their way into clinical practice due to several advantages (e.g. portability, significantly lower purchase cost). However, there is no evidence to date on the accuracy and performance of HHUS in patients with inflammatory arthritis (IA).Objectives:To assess accuracy and performance of a new HHUS machine in comparison to a conventional cart-based sonographic machine in patients with IA.Methods:Consecutive IA patients of our outpatient clinic with at least one tender and swollen joint in the 66/68 joint count were enrolled. US was performed on clinically affected joints with corresponding tendons/entheses using a cart-based sonographic device (“Samsung HS40”) and a HHUS device (“Butterfly iQ”) in standard scan positions. One blinded reader scored all images for the presence of following pathologic findings: erosions, bony enlargement, synovial hyperthrophy, joint effusion, bursitis, tenosynovitis and enthesitis. In addition, synovitis was graded (B Mode and power Doppler (PD)) by the 4-level EULAR-OMERACT scale [1]. To avoid bias by the blinded reader, who otherwise would have been tempted to identify pathological findings for each examined joint, we also included 67 joints of two healthy volunteers into the evaluation. We calculated the overall concordance and the concordance by type of joint and type of pathological finding between the two devices (percentage of observation pairs in which the same rating was given by both devices). The Cohen’s kappa coefficient (κ) with 95% bootstrap confidence intervals was used to assess the agreement between the two US devices. We also measured the time required for the US examination of one joint with both devices.Results:32 patients (20 rheumatoid arthritis, 10 psoriatic arthritis, 1 gouty arthritis, 1 systemic lupus erythematosus) were included in this study. Mean age of patients was 58.2±13.7 years, 63% were females. In total 186 joints were examined. The overall raw concordance in B-mode between the two devices was 97 %, with an overall κappa for agreement of 0.90, 95% CI (0.89, 0.94). No significant differences were found in relation to type of joint or pathological finding examined. The PD-mode of the HHUS device did not detect any PD-signal, whereas the cart-based device detected a PD-signal in 61 joints (33%). The portable device did not offer any time saving compared to the cart-based device (mean time in seconds per examined region: 47 seconds for the HHUS device versus 46.3 seconds for the cart-based device).Conclusion:The HHUS device “Butterfly iQ” has been shown to be accurate in the assessment of structural joint damage and inflammation in patients with IA, but only in B-mode. Significant improvements are still needed to reliable demonstrate blood flow detection by PD mode.

The effect of native knee rotation on the tibial-tubercle-trochlear-groove distance in patients with patellar instability: an analysis of MRI and CT measurements.

This study aimed to quantify the effect of lower limb rotational parameters on the difference in the tibial-tubercle-trochlear-groove (TTTG) distance when assessed with magnetic resonance imaging (MRI) and computed tomography (CT) in patients with patellar instability. It was hypothesized that an increased native knee rotation angle significantly contributes to an underestimation of TTTG by MRI. Forty patients with patellar instability who had undergone standard radiographs, MRI and CT scans were included in this retrospective study. A musculoskeletal radiologist assessed all imaging for TTTG, femoral and tibial rotation, knee rotation and flexion angle, and trochlear dysplasia. ΔTTTG was defined as the TTTG measured on MRI subtracted from the TTTG measured on CT. Statistical analysis determined the effect of these parameters on the calculated difference between TTTG when measured on CT and MRI. Equal knee flexion in MRI and CT resulted in a ΔTTTG of 0.1 ± 0.3mm compared to 4.0 ± 3.3mm in patients with different knee flexion angles in both imaging acquisitions (p = 0.036). The knee rotation angle measured on CT (native knee rotation angle) was negatively correlated with ΔTTTG (r = - 0.365; p = 0.002), while neither tibial nor femoral rotation showed any associations with TTTG (n.s.). Trochlear dysplasia did not show any significant correlation with ΔTTTG, regardless of classification by Dejour or Lippacher (n.s.). Both the native knee rotation angle and the MRI knee flexion angle were independent predictors of ΔTTTG, yet with an opposing effect (knee rotation: 95% Confidence Interval [CI] for β - 0.468 to - 0.154, p < 0.001; knee flexion 95% CI for β 0.292 to 0.587, p < 0.001). Patients with a native knee rotation angle > 20° showed a ΔTTTG of - 5.8 ± 4.0mm (MRI rather overestimates TTTG) compared to 0.9 ± 4.1mm Δ TTTG (MRI rather underestimates TTTG) in patients with < 20° native knee rotation angle. The native knee rotation angle is an independent, inversely correlated predictor of ΔTTTG, thus opposing the effect of knee flexion during MRI acquisition. Consequently, these results suggest that not only knee flexion but also knee rotation should be appreciated when assessing TTTG during patellar instability diagnostic evaluation as it can potentially lead to a false estimation of the TTTG distance on MRI. Level III.

Is minor surgery safe during the COVID-19 pandemic? A multi-disciplinary study

To assess the risk of postoperative SARS-CoV-2 infection during the COVID-19 pandemic. The CONCEPTION study was a cohort, multidisciplinary study conducted at Conception University Hospital, in France, from March 17th to May 11th, 2020. Our study included all adult patients who underwent minor surgery in one of the seven surgical departments of our hospital: urology, digestive, plastic, gynecological, otolaryngology, gynecology or maxillofacial surgery. Preoperative self-isolation, clinical assessment using a standardized questionnaire, physical examination, nasopharyngeal RT-PCR and chest CT scan performed the day before surgery were part of our active prevention strategy. The main outcome was the occurrence of a SARS-CoV-2 infection within 21 days following surgery. The COVID-19 status of patients after discharge was updated during the postoperative consultation and to ensure the accuracy of data, all patients were contacted again by telephone. A total of 551 patients from six different specialized surgical Departments in our tertiary care center were enrolled in our study. More than 99% (546/551) of included patients underwent a complete preoperative Covid-19 screening including RT-PCR testing and chest CT scan upon admission to the Hospital. All RT-PCR tests were negative and in 12 cases (2.2%), preoperative chest CT scans detected pulmonary lesions consistent with the diagnosis criteria for COVID-19. No scheduled surgery was postponed. One patient (0.2%) developed a SARS-CoV-2 infection 20 days after a renal transplantation. No readmission or COVID-19 -related death within 30 days from surgery was recorded. Minor surgery remained safe in the COVID-19 Era, as long as all appropriate protective measures were implemented. These data could be useful to public Health Authorities in order to improve surgical patient flow during a pandemic.

The Reproducibility of Cerebrovascular Reactivity Across MRI Scanners.

Cerebrovascular reactivity (CVR) is defined as the ratio of the cerebral blood flow (CBF) response to an increase in a vasoactive stimulus. We used changes in blood oxygenation level-dependent (BOLD) MRI as surrogates for changes of CBF, and standardized quantitative changes in arterial partial pressure of carbon dioxide as the stimulus. Despite uniform stimulus and test conditions, differences in voxel-wise BOLD changes between testing sites may remain, attributable to physiologic and machine variability. We generated a reference atlas of normal CVR metrics (voxel-wise mean and SD) for each of two sites. We hypothesized that there would be no significant differences in CVR between the two atlases enabling each atlas to be used at any site. A total of 69 healthy subjects were tested to create site-specific atlases, with 20 of those individuals tested at both sites. 38 subjects were scanned at Site 1 (17F, 37.5 ± 16.8 y) and 51 subjects were tested at Site 2 (22F, 40.9 ± 17.4 y). MRI platforms were: Site 1, 3T Magnetom Skyra Siemens scanner with 20-channel head and neck coil; and Site 2, 3T HDx Signa GE scanner with 8-channel head coil. To construct the atlases, test results of individual subjects were co-registered into a standard space and voxel-wise mean and SD CVR metrics were calculated. Map comparisons of z scores found no significant differences between white matter or gray matter in the 20 subjects scanned at both sites when analyzed with either atlas. We conclude that individual CVR testing, and atlas generation are compatible across sites provided that standardized respiratory stimuli and BOLD MRI scan parameters are used. This enables the use of a single atlas to score the normality of CVR metrics across multiple sites.

Diagnostic performance and radiation dose of reduced vs. standard scan range abdominopelvic CT for evaluation of appendicitis.

To compare the diagnostic performance and radiation dose of reduced vs. standard scan range CT in diagnosing appendicitis. We retrospectively evaluated 531 consecutive adults who underwent emergency contrast-enhanced CT for abdominal pain or suspected appendicitis between July 2018 and March 2019. One hundred eighty-one young adults (mean age, 26 ± 6 years) were imaged from L2 to thesymphysis pubis (reduced protocol). A total of 350 older patients (mean age, 55 ± 17 years) and those with a wider differential diagnosis were imaged from thediaphragm to theischium (standard protocol). The reference standard was histopathology (surgical cases) or 3 months of medical record follow-up (nonsurgical cases). Sensitivity, specificity, and accuracy were calculated. Mean dose-length products (DLP) were compared (t-test). Using an anthropomorphic phantom, organ doses were measured on CT scanners with (scanner 1) and without (scanner 2) automatic voltage selection; effective radiation doses were calculated. The frequency of appendicitis was 57/181 (31.5%) and 80/350 (22.9%) in the reduced and standard groups, respectively. Results of the reduced and standard protocols respectively were as follows (95% CI in parentheses): sensitivity, 98.2% (90.4-99.9%) and 100.0 (95.3-100.0%); specificity, 99.2% (95.6-100.0%) and 99.6% (97.9-100.0%); accuracy, 97.8% and 97.4%; mean DLPs, 363 ± 191mGy∙cm and 633 ± 591mGy∙cm (p < 0.0001). Phantom-based measurements of effective dose were 47% lower on scanner 1 (4.64 vs. 2.48 mSv) and 26% lower on scanner 2 (4.68 vs. 3.45 mSv) with the reduced protocol. For young adults with clinically suspected appendicitis, a reduced scan range CT protocol is as sensitive, specific, and accurate as a standard scan range CT and imparts significantly less radiation dose. • A reduced scan range CT protocol in young adults with high suspicion of appendicitis demonstrates similar diagnostic performance as a full-range abdominopelvic CT in undifferentiated adult patients. • The reduced scan range CT protocol imparts significantly less radiation dose: 57% based on dose-length product data and 26-47% based on anthropomorphic phantom data.

Fetal biometric based abnormality detection during prenatal development using deep learning techniques

Early in pregnancy, ultrasounds are used to confirm the fetal heartbeat and a uterine pregnancy. Later, ultrasounds screen for fetal growth, placenta location and umbilical cord, as well as the baby's general health and anatomy. Identifying and interpreting fetal standard scan planes during 2-D ultrasound mid-pregnancy examinations are highly complex tasks, which require years of training. Apart from guiding the probe to the correct location, it is equally difficult for a non-expert to identify relevant structures within the image. The procedure requires a sonographer to find the standardized visualization planes with a probe and manually place measurement calipers on the structures of interest. The process is tedious, time consuming, and introduces user variability into the measurements. Automatic image processing can provide tools to help experienced as well as inexperienced operators with these tasks. The proposed method is realized with deep convolutional neural network models to find the region of interest (ROI) of the fetal biometric and organs region in the US image. Based on the ROI, AlexNet, GoogleNet and CNN evaluate the image quality by assessing the goodness of depiction for the key structures of fetal biometrics. In this method both normal and abnormal US data are considered. In addition with that the input sources of the neural network are augmented with the local phase features along with the original US data. These augmented input sources helps to improve the performance of the various Neural Networks. The input sources are trained by AlexNet, GoogleNet and CNN. Then the process of validation is done by performance in proposed Networks for evaluating the accuracy. The performance of proposed work is evaluated with different network configuration. On the dataset of 400 images used in this classification task, proposed work of AlexNet, GoogleNet and CNN achieves accuracy of 90.43%, 88.70%, and 81.25% with reference to expert’s ground truth results respectively.

Accuracy of automatic structure propagation for daily magnetic resonance image-guided head and neck radiotherapy

Background and purpose Deformable image registration (DIR) and contour propagation are used in daily online adaptation for hybrid MRI linac (MRL) treatments. The accuracy of the propagated contours may vary depending on the chosen workflow (WF), affecting the amount of required manual corrections. This study investigated the impact of three different WFs of contour propagations produced by a clinical treatment planning system for a high-field MRL on head and neck cancer patients. Methods Seventeen patients referred for curative radiotherapy for oropharyngeal cancer underwent standard CT-based dose planning and MR scans in the treatment position for planning (pMR), and at the 10th (MR10), 20th (MR20) and 30th (MR30) fraction (±2). The primary tumour, a metastatic lymph node and 8 organs at risk were manually delineated on each set of T2 weighted images. Delineations were repeated one month later on the pMR by the same observer to determine the intra-observer variation (IOV). Three WFs were used to deform images in the treatment planning system for the high-field MRL: In WF1, only the planning image and contours were used as a reference for DIR and propagation to MR10,20,30. The most recently acquired image set prior to the daily images was deformed and uncorrected (WF2) versus manually corrected (WF3) structures propagated to the session image. Dice similarity coefficient (DSC), mean surface distance (MSD) and Hausdorff distance (HD) were calculated for each structure in each model. Results Population median DSC, MSD and HD for WF1 and WF3 were similar and slightly better than for WF2. WF3 provided higher accuracy than WF1 for structures that are likely to shrink. All DIR workflows were less accurate than the IOV. Conclusions WF1 and WF3 provide higher accuracy in structure propagation than WF2. Manual revision and correction of propagated structures are required for all evaluated workflows.

Ferumoxytol-enhanced ultrashort TE MRA and quantitative morphometry of the human kidney vasculature

To evaluate the feasibility of Quantitative Ultrashort-Time-to-Echo Contrast-Enhanced (QUTE-CE) MRA using ferumoxytol as a contrast agent for abdominal angiography in the kidney. Four subjects underwent ferumoxytol-enhanced MRA with the 3D UTE Spiral VIBE WIP sequence at 3T. Image quality metrics were quantified, specifically the blood Signal-to-Noise Ratio (SNR), blood-tissue Contrast-to-Noise Ratio (CNR) and Intraluminal Signal Heterogeneity (ISH) from both the aorta and inferior vena cava (IVC). Morphometric analysis of the vessels was performed using manual approach and semi-automatic approach using Vascular Modeling ToolKit (VMTK). Image quality and branching order were compared between QUTE-CE MRA and the Gadolinium (Gd) CEMRA reference image. QUTE-CE MRA provides a bright blood snapshot that delineates arteries and veins equally in the same scan. The maximum SNR and CNR values were 3,282 ± 1,218 and 1,295 ± 580, respectively - significantly higher than available literature values using other CEMRA techniques. QUTE-CE MRA had lower ISH and depicted higher vessel branching order (7th vs 3rd) within the kidney compared to a standard dynamic clinical Gd CEMRA scan. Morphometric analysis yielded quantitative results for the total kidney volume, total cyst volume and for diameters of the branching arterial network down to the 7th branch. Vessel curvature was significantly increased (p < 0.001) in the presence of a renal cyst compared to equivalent vessels in normal kidney regions. QUTE-CE MRA is feasible for kidney angiography, providing greater detail of kidney vasculature, enabling quantitative morphometric analysis of the abdominal and intra-renal vessels and yielding metrics relevant to vascular diseases while using a contrast agent ferumoxytol that is safe for CKD patients.

Performance of an artificial intelligence tool with real-time clinical workflow integration - Detection of intracranial hemorrhage and pulmonary embolism.

Performance of an artificial intelligence tool with real-time clinical workflow integration - Detection of intracranial hemorrhage and pulmonary embolism.