Learning from the machine: AI assistance is not an effective learning tool for resident education in chest x-ray interpretation

OBJECTIVES

To assess whether a computer-aided detection (CADe) system could serve as a learning tool for radiology residents in chest X-ray (CXR) interpretation.

METHODS

Eight radiology residents were asked to interpret 500 CXRs for the detection of five abnormalities, namely pneumothorax, pleural effusion, alveolar syndrome, lung nodule, and mediastinal mass. After interpreting 150 CXRs, the residents were divided into 2 groups of equivalent performance and experience. Subsequently, group 1 interpreted 200 CXRs from the "intervention dataset" using a CADe as a second reader, while group 2 served as a control by interpreting the same CXRs without the use of CADe. Finally, the 2 groups interpreted another 150 CXRs without the use of CADe. The sensitivity, specificity, and accuracy before, during, and after the intervention were compared.

RESULTS

Before the intervention, the median individual sensitivity, specificity, and accuracy of the eight radiology residents were 43% (range: 35-57%), 90% (range: 82-96%), and 81% (range: 76-84%), respectively. With the use of CADe, residents from group 1 had a significantly higher overall sensitivity (53% [n = 431/816] vs 43% [n = 349/816], p < 0.001), specificity (94% [i = 3206/3428] vs 90% [n = 3127/3477], p < 0.001), and accuracy (86% [n = 3637/4244] vs 81% [n = 3476/4293], p < 0.001), compared to the control group. After the intervention, there were no significant differences between group 1 and group 2 regarding the overall sensitivity (44% [n = 309/696] vs 46% [n = 317/696], p = 0.666), specificity (90% [n = 2294/2541] vs 90% [n = 2285/2542], p = 0.642), or accuracy (80% [n = 2603/3237] vs 80% [n = 2602/3238], p = 0.955).

CONCLUSIONS

Although it improves radiology residents' performances for interpreting CXRs, a CADe system alone did not appear to be an effective learning tool and should not replace teaching.

CLINICAL RELEVANCE STATEMENT

Although the use of artificial intelligence improves radiology residents' performance in chest X-rays interpretation, artificial intelligence cannot be used alone as a learning tool and should not replace dedicated teaching.

KEY POINTS

• With CADe as a second reader, residents had a significantly higher sensitivity (53% vs 43%, p < 0.001), specificity (94% vs 90%, p < 0.001), and accuracy (86% vs 81%, p < 0.001), compared to residents without CADe. • After removing access to the CADe system, residents' sensitivity (44% vs 46%, p = 0.666), specificity (90% vs 90%, p = 0.642), and accuracy (80% vs 80%, p = 0.955) returned to that of the level for the group without CADe.

Prospective Phase II Trial of Primary Lung Tumor Stereotactic Body Radiation Therapy (SBRT) Followed By Concurrent Mediastinal Chemoradiation and Adjuvant Immunotherapy for Locally-Advanced Non-Small Cell Lung Cancer (LA NSCLC)

PURPOSE/OBJECTIVE(S)

To report the efficacy and toxicity outcomes of a prospective phase II trial of primary tumor SBRT followed by conventional chemoradiation to the lymph nodes and adjuvant immunotherapy in patients (pts) with unresectable LA NSCLC.

MATERIALS/METHODS

Eligible pts included stage II-III LA NSCLC with peripheral primary tumors ≤ 7cm or centrally based tumors that had at least 2 cm separation from involved nodal disease. Pts received SBRT to the primary tumor (50-54 Gy in 3-5 fractions) followed by standard radiation to 60 Gy in 30 fractions to the involved lymph nodes with concurrent platinum doublet chemotherapy. The trial was amended to allow pts without disease progression after chemoradiation to receive adjuvant durvalumab per the PACIFIC trial. The primary endpoint was 1 year progression free survival (PFS), evaluated as a binary variable. Frequencies and proportions were used for reporting this primary endpoint, in addition to adverse events and patterns of failure. Median PFS and OS were estimated using Kaplan Meier methods.

RESULTS

Safety and efficacy is reported on the first 50 pts enrolled in the trial with a median follow-up of 24 months (mos) (range, 1-54 mos). Pts were primarily stage IIIA (60%) or stage IIIB (34%), with 6% of pts stage IIB. Overall grade 3 or higher toxicity related to SBRT and/or mediastinal radiation was 8% with two pts (4%) developing grade 3 pneumonitis and one pt having a grade 5 lung infection possibly related to radiation. Overall grade 2 pneumonitis related to SBRT or mediastinal radiation was 20%. Only one pt (2%) developed grade 3 esophagitis. No late cardiac events have been observed. The one-year PFS for all pts was 62% with a median PFS of 26.3 mos and median overall survival of 40.8 mos. Of the 50 pts enrolled, 37 received at least one dose of adjuvant durvalumab. The one-year PFS for pts who received at least one dose of durvalumab was 70.3% with a median PFS not yet reached in this group (median follow-up 24 mos). Patterns of failure were mostly distant with 26% of pts experiencing distant failure, 6% regional, and 2% distant and regional. There was only one local failure (2%) after SBRT in all 50 pts.

CONCLUSION

SBRT to the primary tumor followed by conventional chemoradiation to the involved lymph nodes and adjuvant immunotherapy was well tolerated and showed improved 1-year PFS compared to prior conventional chemoradiation trials for locally advanced NSCLC. The results of this trial will be further evaluated in a randomized phase III study, NRG LU-008. Pts will receive either conventional chemoradiation vs. SBRT to the primary tumor followed by chemoradiation to the involved lymph nodes followed by consolidative immunotherapy to evaluate the possibility of utilization of SBRT as a new standard of care for LA NSCLC.

Appropriate use of morphological imaging for assessing treatment response and disease progression of neuroendocrine tumors

Neuroendocrine tumors (NETs) are relatively rare neoplasms displaying heterogeneous clinical behavior, ranging from indolent to aggressive forms. Patients diagnosed with NETs usually receive a varied array of treatments, including somatostatin analogs, locoregional treatments (ablation, intra-arterial therapy), cytotoxic chemotherapy, peptide receptor radionuclide therapy (PRRT), and targeted therapies. To maximize therapeutic efficacy while limiting toxicity (both physical and economic), there is a need for accurate and reliable tools to monitor disease evolution and progression and to assess the effectiveness of these treatments. Imaging morphological methods, primarily relying on computed tomography (CT) and magnetic resonance imaging (MRI), are indispensable modalities for the initial evaluation and continuous monitoring of patients with NETs, therefore playing a pivotal role in gauging the response to treatment. The primary goal of assessing tumor response is to anticipate and weigh the benefits of treatments, especially in terms of survival gain. The World Health Organization took the pioneering step of introducing assessment criteria based on cross-sectional imaging. This initial proposal standardized the measurement of lesion sizes, laying the groundwork for subsequent criteria. The Response Evaluation Criteria in Solid Tumors (RECIST) subsequently refined and enhanced these standards, swiftly gaining acceptance within the oncology community. New treatments were progressively introduced, targeting specific features of NETs (such as tumor vascularization or expression of specific receptors), and achieving significant qualitative changes within tumors, although associated with minimal or paradoxical effects on tumor size. Several alternative criteria, adapted from those used in other cancer types and focusing on tumor viability, the slow growth of NETs, or refining the existing size-based RECIST criteria, have been proposed in NETs. This review article aims to describe and discuss the optimal utilization of CT and MRI for assessing the response of NETs to treatment; it provides a comprehensive overview of established and emerging criteria for evaluating tumor response, along with comparative analyses. Molecular imaging will not be addressed here and is covered in a dedicated article within this special issue.

Fragility index of positive phase II and III randomised clinical trials of treatments for hepatocellular carcinoma (2002-2022)

Background & Aims

The fragility index (FI), i.e., theminimum number of best survivors reassigned to the control group required to revert the statistically significant result of a clinical trial to non-significant, is a metric to evaluate the robustness of randomized controlled trials (RCTs). We aimed to assess the FI in the field of HCC.

Methods

This is a retrospective analysis of phase 2 and 3 RCTs for the treatment of HCC published between 2002 and 2022. We included two-arm studies with 1:1 randomization and significant positive results for a primary time-to-event endpoint for the FI calculation, which involves the iterative addition of a best survivor from the experimental group to the control group, until positive significance (p <0,05, Log-rank test) is lost.

Results

We identified 51 phase 2 and 3 positive RCTs, of which 29 (57%) were eligible for fragility index calculation. After reconstruction of the Kaplan-Meier curves, 25/29 studies remained significant, among which the analysis was performed. The median (interquartile range (IQR)) FI was 5 (2-10) and Fragility Quotient (FQ) was 3% (1%-6%). Ten trials (40%) had a FI of 2 or less. FI was positively correlated to the blind assessment of the primary endpoint (median FI 9 with blind assessment versus 2 without, p = 0.01), the number of reported events in the control arm (RS = 0.45, p = 0.02) and to impact factor (RS = 0.58, p = 0.003).

Conclusions

Several phases 2 and 3 RCTs in HCC have a low fragility index, underlying the limited robustness on the conclusion of their superiority over control treatments. The fragility index might provide an additional tool to assess the robustness of clinical trial data in HCC.

Impact and implications

The fragility index is a method to assess robustness of a clinical trial and is defined the minimum number of best survivors reassigned to the control group required to revert the statistically significant result of a clinical trial to non-significant. Among 25 randomised controlled trials in HCC, the median fragility index was 5, and 10 trials among 25 (40%) had a fragility index of 2 or less, indicating an important fragility.

Adherence to LI-RADS and EASL high-risk population criteria: A systematic review

BACKGROUND AND AIMS

The Liver Imaging Reporting and Data System (LI-RADS) and European Association for the Study of the Liver (EASL) diagnostic criteria for noninvasive diagnosis of HCC can only be applied to patients at a high risk of HCC. This systematic review assesses adherence to the LI-RADS and EASL high-risk population criteria in published studies.

APPROACH AND RESULTS

PubMed was searched for original research, published between January 2012 and December 2021, reporting LI-RADS and EASL diagnostic criteria on contrast-enhanced ultrasound, CT, or MRI. The algorithm version, publication year, risk status, and etiologies of chronic liver disease were recorded for each study. Adherence to high-risk population criteria was evaluated as optimal (unequivocal adherence), suboptimal (equivocal), or inadequate (clear violation). A total of 219 original studies were included, with 215 that used the LI-RADS criteria, 4 EASL only, and 15 that evaluated both LI-RADS and EASL criteria. Optimal, suboptimal, or inadequate adherence to high-risk population criteria was observed in 111/215 (51.6%), 86/215 (40.0%), and 18/215 (8.4%) LI-RADS and 6/19 (31.6%), 5/19 (26.3%), and 8/19 (42.1%) EASL studies ( p < 0.001) regardless of the imaging modality. Adherence to high-risk population criteria significantly improved according to the CT/MRI LI-RADS versions (optimal in v2018 in 64.5% of studies; v2017, 45.8%; v2014, 24.4%; v2013.1, 33.3%; p < 0.001) and the publication year (2020-2021, 62.5%; 2018-2019, 33.9%; 2014-2017, 39.3% of all LI-RADS studies; p = 0.002). No significant differences in adherence to high-risk population criteria were observed in the versions of contrast-enhanced ultrasound LI-RADS ( p = 0.388) or EASL ( p = 0.293).

CONCLUSION

Adherence to high-risk population criteria was optimal or suboptimal in about 90% and 60% of LI-RADS and EASL studies, respectively.

Hepatic transarterial locoregional therapy in patients with contraindications to hepatectomy after portal vein embolization: safety and effectiveness

We assessed the safety and effectiveness of hepatic transarterial loco-regional therapy (LRT) including chemoembolization (TACE) and radioembolization (TARE) in patients who underwent portal vein embolization (PVE) before major hepatectomy in whom surgery was then contraindicated. Adverse events (AE) were graded according to new SIR Classification of Adverse Events. Tumor response was assessed by RECIST 1.1. Overall (OS) and progression-free survivals (PFS) were estimated. Fifteen patients had 37 transarterial LRT (25 TACE, 11 TARE, one bland embolization), most (73%) with hepatocellular carcinoma. Eleven AE occurred in seven patients, including two grade 3/5 (severe) and two grade 4/5 (life-threatening). The best response was partial for four (27%) and stable disease for ten (66%) patients. Median OS and PFS were 42 [95% Confidence interval (CI) 35-49 months], 33 months (CI95% 24-42 months), respectively. In conclusion hepatic transarterial LRT can be considered as a therapeutic option in patients with contraindicated liver surgery after PVE.

Defining textbook outcome for selective internal radiation therapy of hepatocellular carcinoma: an international expert study

BACKGROUND

A textbook outcome (TO) is a composite indicator covering the entire intervention process in order to reflect the "ideal" intervention and be a surrogate for patient important outcomes. Selective internal radiation therapy (SIRT) is a complex multidisciplinary and multistep intervention facing the challenge of standardization. This expert opinion-based study aimed to define a TO for SIRT of hepatocellular carcinoma.

METHODS

This study involved two steps: (1) the steering committee (4 interventional radiologists) first developed an extensive list of possible relevant items reflecting an optimal SIRT intervention based on a literature review and (2) then conducted an international and multidisciplinary survey which resulted in the final TO. This survey was online, from February to July 2021, and consisted three consecutive rounds with predefined settings. Experts were identified by contacting senior authors of randomized trials, large observational studies, or studies on quality improvement in SIRT. This study was strictly academic.

RESULTS

A total of 50 items were included in the first round of the survey. A total of 29/40 experts (73%) responded, including 23 interventional radiologists (79%), three nuclear medicine physicians (10%), two hepatologists, and one oncologist, from 11 countries spanning three continents. The final TO consisted 11 parameters across six domains ("pre-intervention workup," "tumor targeting and dosimetry," "intervention," "post-⁹⁰Y imaging," "length of hospital stay," and "complications"). Of these, all but one were applied in the institutions of > 80% of experts.

CONCLUSIONS

This multidimensional indicator is a comprehensive standardization tool, suitable for routine care, clinical round, and research.

Reperfusion injury on computed tomography following endovascular revascularization of acute mesenteric ischemia: prevalence, risk factors, and patient outcome

BACKGROUND

Data about reperfusion injury (RI) following acute arterial mesenteric ischemia (AAMI) in humans are scarce. We aimed to assess the prevalence and risk factors of RI following endovascular revascularization of AMI and evaluate its impact on patient outcomes.

METHODS

Patients with AAMI who underwent endovascular revascularization (2016-2021) were included in this retrospective cohort. CT performed < 7 days after treatment was reviewed to identify features of RI (bowel wall hypoattenuation, mucosal hyperenhancement). Clinical, laboratory, imaging, and treatments were compared between RI and non-RI patients to identify factors associated with RI. Resection rate and survival were also compared.

RESULTS

Fifty patients (23 men, median 72-yrs [IQR 60-77]) were included, and 22 were diagnosed with RI (44%) after a median 28 h (22-48). Bowel wall hypoattenuation and mucosal hyperenhancement were found in 95% and 91% of patients with post-interventional RI, respectively. Patients with RI had a greater increase of CRP levels after endovascular treatment (p = 0.01). On multivariate analysis, a decreased bowel wall enhancement on baseline CT (HR = 8.2), an embolic cause (HR = 7.4), complete SMA occlusion (HR = 7.0), and higher serum lactate levels (HR = 1.4) were associated with RI. The three-month survival rate was 78%, with no difference between subgroups (p = 0.99). However, the resection rate was higher in patients with RI (32% versus 7%; p = 0.03).

CONCLUSION

RI is frequent after endovascular revascularization of AAMI, especially in patients who present with decreased bowel wall enhancement on pre-treatment CT, an embolic cause, and a complete occlusion of the SMA. However, its occurrence does not seem to negatively impact short-term survival.

MRI is useful to suggest and exclude malignancy in mucinous cystic neoplasms of the pancreas

OBJECTIVES

To evaluate the value of MRI in differentiating benign (b-MCN) and malignant (m-MCN) MCN. European guidelines suggest that certain mucinous cystic neoplasms (MCN) of the pancreas can be conservatively managed.

METHODS

A retrospective single-center study of consecutive patients with resected MCN. MRIs were independently reviewed by two readers blinded to the pathological results. The authors compared b-MCN (i.e., mucinous-cystadenoma comprising high-grade dysplasia (HGD)) and m-MCN (i.e., cystadenocarcinoma).

RESULTS

Sixty-three patients (62 women [98%]) with 63 MCN (6 m-MCN, 2 HGD) were included. m-MCN tumors had a tendency to be larger than b-MCN (median 86 [25-103] vs. 45 [17-130] mm, p = .055). The combination of signal heterogeneity on T2-weighted imaging, wall thickness ≥ 5 mm, the presence of mural nodules ≥ 9 mm, and enhancing septa had an area under the ROC curve of 0.97 (95% CI 0.91-1.00) for the diagnosis of m-MCN. A total of 24 (37%), 20 (32%), 10 (16%), 5 (8%), and 4 (6%) out of 63 MCNs showed 0, 1, 2, 3, and 4 of these features, respectively. The corresponding rate of m-MCN was 0%, 0%, 10%, 20%, and 100%, respectively, with a good-to-excellent inter-reader agreement. Patterns with a high NPV for m-MCN included an absence of enhancing septa or walls (NPV 97% and 100%, respectively), wall thickness < 3 mm (NPV 100%), and no mural nodules (NPV 100%).

CONCLUSIONS

A combination of 4 imaging features suggests malignant MCN on MRI. On the other hand, visualization of a thin non-enhancing wall with no mural nodules suggests benign MCN.

KEY POINTS

• A heterogenous signal on T2-weighted MRI, a ≥ 5-mm-thick wall, mural nodules ≥ 9 mm, and/or enhancing septa suggest malignant MCNs. • A thin non-enhancing wall with no mural nodules suggests benign MCNs. • MRI should be performed in the pre-therapeutic evaluation of MCN to help determine the therapeutic strategy in these patients.

O49 The use of augmented reality for surgical guidance: an assessment of the human error

Introduction

Microsoft HoloLens® is an augmented-reality headset which is increasingly used for surgical guidance. This headset allows the overlay of patient-specific virtual models obtained from medical images onto the patient’s body surface using automatic marker-based alignment. This can guide surgeons during certain surgical tasks, e.g. determining biopsy needle entry points. This study aims to measure the human error in the localisation of virtual models with the headset and discuss its surgical implications.

Method

59 adults were recruited between the ages of 20–59 years. A 12 cm2 digital marker was displayed on a monitor in 9 different positions, one at a time. This was repeated 3 times, resulting in 27 markers shown to each participant. Once a marker was detected by the headset’s camera, a virtual hexagon was rendered on the headset’s transparent lenses. Participants were tasked to click on the hexagon’s vertices using a mouse. The clicks’ coordinates were recorded by the system and compared to the predicted coordinates. This allowed for the calculation of the vertex localisation error.

Result

The mean vertex localisation error was found to be 5.19 mm (±3.56) with a range from 0.08 to 29.77 mm. There was a significant difference between marker positions as determined by a one-way ANOVA (P &lt; 0.001).

Conclusion

This study suggests that the error in the localisation of virtual models depends on the position of the markers relative to the user wearing the headset. Further research is required to explore whether training can reduce the human error with this headset.

Take-home Message

The range of the human error in localising virtual models via the Microsoft HoloLens® headset is large and may be dependent on the position of the marker relative to the user of the headset. Further research is needed to investigate whether training with the headset can improve human performance.

HCC advances in diagnosis and prognosis: Digital and Imaging

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Understanding of the pathogenesis of HCC has significantly improved in the past few years due to advances in genetics, molecular biology and pathology. Several subtypes have been identified with different backgrounds and outcomes, leading to possible changes in disease management and challenging the role of imaging. Indeed, despite its pivotal role in the diagnostic workup, prognosis, and the decision-making process in patients with HCC, these recent developments are progressively redefining the role of imaging. First and most important, liver imaging is shifting from a purely qualitative to a quantitative paradigm, integrating quantitative imaging and radiomics in a digital era. Second, to improve patient management, imaging has gradually moved beyond tumor-centered assessment to include a broader evaluation of the liver and its function. This review describes and discusses these advances in the imaging for the diagnosis and prognosis of HCC.

The Glenoid Vault Outer Cortex a new more accurate radiological reference for shoulder arthroplasty

Introduction: Correct positioning of the glenoid component is an important determinant of outcome in shoulder arthroplasty. We describe and assess a new radiological plane of reference for improving the accuracy of glenoid preparation prior to component implantation – the Glenoid Vault Outer Cortex (GvOC) plane. Methods: One hundred and five CT scans of normal scapulae were obtained. Forty six females and 59 males aged between 22 and 30 years. The accuracy of the GvOC plane was then compared against the current “gold standard” – the scapular border (SB). Measurements of glenoid inclination, version, rotation, and offset were obtained using both the GvOC and SB planes. These were then compared to actual values. Results: The mean difference between version obtained using the GvOC plane and the actual value was 1.8° (−2 to 5, SD 1.6) as compared to 6.7° (−2 to 17, SD 4.3) when the SB plane was used, (p < 0.001). The mean difference between estimates of inclination obtained using the GvOC plane and the actual were 1.9° (−4 to 6, SD 1.6) as compared to 11.2° (−4 to 25, SD 6.1) when the SB plane was used, (p < 0.001). Conclusions: The GvOC plane produced estimates of glenoid version and inclination closer to actual values with lower variance than when the SB plane was used. The GvOC may be a more accurate and reproducible radiological method for surgeons to use when defining glenoid anatomy prior to arthroplasty surgery.

Efficacy of Chest CT for COVID-19 Pneumonia Diagnosis in France

Background The role and performance of chest CT in the diagnosis of the coronavirus disease 2019 (COVID-19) pandemic remains under active investigation. Purpose To evaluate the French national experience using chest CT for COVID-19, results of chest CT and reverse transcription polymerase chain reaction (RT-PCR) assays were compared together and with the final discharge diagnosis used as the reference standard. Materials and Methods A structured CT scan survey (NCT04339686) was sent to 26 hospital radiology departments in France between March 2, 2020, and April 24, 2020. These dates correspond to the peak of the national COVID-19 epidemic. Radiology departments were selected to reflect the estimated geographic prevalence heterogeneities of the epidemic. All symptomatic patients suspected of having COVID-19 pneumonia who underwent both initial chest CT and at least one RT-PCR test within 48 hours were included. The final discharge diagnosis, based on multiparametric items, was recorded. Data for each center were prospectively collected and gathered each week. Test efficacy was determined by using the Mann-Whitney test, Student t test, χ2 test, and Pearson correlation coefficient. P < .05 indicated a significant difference. Results Twenty-six of 26 hospital radiology departments responded to the survey, with 7500 patients entered; 2652 did not have RT-PCR test results or had unknown or excess delay between the RT-PCR test and CT. After exclusions, 4824 patients (mean age, 64 years ± 19 [standard deviation], 2669 male) were included. With final diagnosis as the reference, 2564 of the 4824 patients had COVID-19 (53%). Sensitivity, specificity, negative predictive value, and positive predictive value of chest CT in the diagnosis of COVID-19 were 2319 of 2564 (90%; 95% CI: 89, 91), 2056 of 2260 (91%; 95% CI: 91, 92), 2056 of 2300 (89%; 95% CI: 87, 90), and 2319 of 2524 (92%; 95% CI: 91, 93), respectively. There was no significant difference for chest CT efficacy among the 26 geographically separate sites, each with varying amounts of disease prevalence. Conclusion Use of chest CT for the initial diagnosis and triage of patients suspected of having coronavirus disease 2019 was successful. © RSNA, 2021 Online supplemental material is available for this article.

Individuals with high bone mass have increased progression of radiographic and clinical features of knee osteoarthritis

OBJECTIVE

High bone mass (HBM) is associated with an increased prevalence of radiographic knee OA (kOA), characterized by osteophytosis. We aimed to determine if progression of radiographic kOA, and its sub-phenotypes, is increased in HBM and whether observed changes are clinically relevant.

DESIGN

A cohort with and without HBM (L1 and/or total hip bone mineral density Z-score≥+3.2) had knee radiographs collected at baseline and 8-year follow-up. Sub-phenotypes were graded using the OARSI atlas. Medial/lateral tibial/femoral osteophyte and medial/lateral joint space narrowing (JSN) grades were summed and Δosteophytes, ΔJSN derived. Pain, function and stiffness were quantified using the WOMAC questionnaire. Associations between HBM status and sub-phenotype progression were determined using multivariable linear/poisson regression, adjusting for age, sex, height, baseline sub-phenotype grade, menopause, education and total body fat mass (TBFM). Generalized estimating equations accounted for individual-level clustering.

RESULTS

169 individuals had repeated radiographs, providing 330 knee images; 63% had HBM, 73% were female, mean (SD) age was 58 (12) years. Whilst HBM was not clearly associated with overall Kellgren-Lawrence measured progression (RR = 1.55 [0.56.4.32]), HBM was positively associated with both Δosteophytes and ΔJSN individually (adjusted mean differences between individuals with and without HBM 0.45 [0.01.0.89] and 0.15 [0.01.0.29], respectively). HBM individuals had higher WOMAC knee pain scores (β = 7.42 [1.17.13.66]), largely explained by adjustment for osteophyte score (58% attenuated) rather than JSN (30% attenuated) or TBFM (16% attenuated). The same pattern was observed for symptomatic stiffness and functional limitation.

CONCLUSIONS

HBM is associated with osteophyte progression, which appears to contribute to increased reported pain, stiffness and functional loss.

Subregional statistical shape modelling identifies lesser trochanter size as a possible risk factor for radiographic hip osteoarthritis, a cross-sectional analysis from the Osteoporotic Fractures in Men Study

OBJECTIVE

Statistical shape modelling (SSM) of hip dual-energy X-ray absorptiometry (DXA) scans has identified relationships between hip shape and radiographic hip OA (rHOA). We aimed to further elucidate shape characteristics related to rHOA by focusing on subregions identified from whole-hip shape models.

METHOD

SSM was applied to hip DXAs obtained in the Osteoporotic Fractures in Men Study. Whole-hip shape modes (HSMs) associated with rHOA were combined to form a composite at-risk-shape. Subsequently, subregional HSMs (cam-type and lesser trochanter modes) were built, and associations with rHOA were examined by logistic regression. Subregional HSMs were further characterised, by examining associations with 3D-HSMs derived from concurrent hip CT scans.

RESULTS

4,098 participants were identified with hip DXAs and radiographs. Composite shapes from whole-hip HSMs revealed that lesser trochanter size and cam-type femoral head are related to rHOA. From sub-regional models, lesser trochanter mode (LTM)1 [OR 0.74; 95%CI 0.63.0.87] and cam-type mode (CTM)3 [OR 1.27; 1.13.1.42] were associated with rHOA, associations being similar to those for whole hip HSMs. 515 MrOS participants had hip DXAs and 3D-HSMs derived from hip CT scans. LTM1 was associated with 3D-HSMs that also represented a larger lesser trochanter [3D-HSM7 (beta (β)-0.23;-0.33,-0.14) and 3D-HSM9 (β0.36; 0.27.0.45)], and CTM3 with 3D-HSMs describing cam morphology [3D-HSM3 (β-0.16;-0.25,-0.07) and 3D-HSM6 (β 0.19; 0.10.0.28)].

CONCLUSION

Subregional SSM of hip DXA scans suggested larger lesser trochanter and cam morphology underlie associations between overall hip shape and rHOA. 3D hip modelling suggests our subregional SSMs represent true anatomical variations in hip shape, warranting further investigation.

COVID-19 impact assessment on the French radiological centers: a nationwide survey

PURPOSE

To determine the impact of the COVID-19 on the CT activities in French radiological centers during the epidemic peak.

MATERIALS AND METHODS

A cross-sectional prospective CT scan survey was conducted between March 16 and April 12, 2020, in accordance with the local IRB. Seven hundred nine radiology centers were invited to participate in a weekly online survey. Numbers of CT examinations related to COVID-19 including at least chest (CT_covid) and whole chest CT scan activities (CT_chest) were recorded each week. A sub-analysis on French departments was performed during the 4 weeks of the study. The impact of the number of RT-PCRs (reverse transcriptase polymerase chain reactions) on the CT workflow was tested using two-sample t test and Pearson's test.

RESULTS

Five hundred seventy-seven structures finally registered (78%) with mean response numbers of 336 ± 18.9 (323; 351). Mean CT_chest activity per radiologic structure ranged from 75.8 ± 133 (0-1444) on week 12 to 99.3 ± 138.6 (0-1147) on week 13. Mean ratio of CT_covid on CT_chest varied from 0.36 to 0.59 on week 12 and week 14 respectively. There was a significant relationship between the number of RT-PCR performed and the number of CT_covid (r = 0.73, p = 3.10^-16) but no link with the number of positive RT-PCR results.

CONCLUSION

In case of local high density COVID-19, CT workflow is strongly modified and redirected to the management of these specific patients.

KEY POINTS

• Over the 4-week survey period, 117,686 chest CT (CT_total) were performed among the responding centers, including 61,784 (52%) CT performed for COVID-19 (CT_covid). • Across the country, the ratio CT_covid/CT_total varied from 0.36 to 0.59 and depended significantly on the local epidemic density (p = 0.003). • In clinical practice, in a context of growing epidemic, in France, chest CT was used as a surrogate to RT-PCR for patient triage.

Evaluation of liver tumour response by imaging

The goal of assessing tumour response on imaging is to identify patients who are likely to benefit - or not - from anticancer treatment, especially in relation to survival. The World Health Organization was the first to develop assessment criteria. This early score, which assessed tumour burden by standardising lesion size measurements, laid the groundwork for many of the criteria that followed. This was then improved by the Response Evaluation Criteria in Solid Tumours (RECIST) which was quickly adopted by the oncology community. At the same time, many interventional oncology treatments were developed to target specific features of liver tumours that result in significant changes in tumours but have little effect on tumour size. New criteria focusing on the viable part of tumours were therefore designed to provide more appropriate feedback to guide patient management. Targeted therapy has resulted in a breakthrough that challenges conventional response criteria due to the non-linear relationship between response and tumour size, requiring the development of methods that emphasize the appearance of tumours. More recently, research into functional and quantitative imaging has created new opportunities in liver imaging. These results have suggested that certain parameters could serve as early predictors of response or could predict later tumour response at baseline. These approaches have now been extended by machine learning and deep learning. This clinical review focuses on the progress made in the evaluation of liver tumours on imaging, discussing the rationale for this approach, addressing challenges and controversies in the field, and suggesting possible future developments.

Limited added value of contrast-enhanced ultrasound over B-mode for the subtyping of hepatocellular adenomas

PURPOSE

To compare the features of hepatocellular adenoma subtypes (HCAs) in B-mode and contrast-enhanced ultrasound (CEUS).

METHOD

Thirty-three patients (31 women [94 %] and two men [6%], median age [Q1-Q3] 43.5 years old [35-51]) with 44 pathologically proven and subtyped HCAs (including 29 inflammatory HCAs [I-HCA] and 15 HNF1-α inactivated HCAs [H-HCA]) who underwent CEUS were included. The features of HCA on B-mode and CEUS were independently reviewed by two radiologists and compared between HCA subtypes.

RESULTS

I-HCAs were mostly hypoechoic (23/29, 79 %) or isoechoic (4/29, 14 %) with B-mode. Twelve of them (41 %) were heterogeneous. All H-HCAs except one demonstrated homogeneous hyperechogenicity (93 %) (p = 0.001). Moderate or marked liver steatosis was only observed in I-HCAs (12/29, 41 %) (p = 0.001). Arterial hyperenhancement was observed on CEUS in 27/29 (93 %) I-HCAs and in 14/15 (93 %) H-HCAs (p=0.98). Washout was present in 6/29 (21 %) I-HCAs and 1/15 (7%) H-HCAs (p=0.27). A total of 23/29 (79 %) I-HCAs and 15/15 (100 %) HCAs were homogeneous on portal and delayed phase acquisitions (p=0.04). The specificity for identifying an H-HCA was 100 % when the lesion was homogeneous and hyperechoic on B-mode, and the sensibility to rule out an H-HCA was 100 % if neither of these two features was present in a liver with obvious steatosis.

CONCLUSIONS

Most CEUS features, especially enhancement patterns, do not significantly differ between HCA subtypes. When HCA is suspected on CEUS, B-mode features should be considered, and a combination of lesion hyperechogenicity, homogeneity and the absence of obvious liver steatosis may be useful to distinguish H-HCAs from I-HCAs.

Top 10 Reviewer Critiques of Radiology Artificial Intelligence (AI) Articles: Qualitative Thematic Analysis of Reviewer Critiques of Machine Learning/Deep Learning Manuscripts Submitted to JMRI

BACKGROUND

Classical machine learning (ML) and deep learning (DL) articles have rapidly captured the attention of the radiology research community and comprise an increasing proportion of articles submitted to JMRI, of variable reporting and methodological quality.

PURPOSE

To identify the most frequent reviewer critiques of classical ML and DL articles submitted to JMRI.

STUDY TYPE

Qualitative thematic analysis.

POPULATION

In all, 1396 manuscript journal articles submitted to JMRI for consideration in 2018, with thematic analysis performed of reviewer critiques of 38 artificial intelligence (AI) articles, comprised of 24 ML and 14 DL articles, from January 9, 2018 to June 2, 2018.

FIELD STRENGTH/SEQUENCE

N/A.

ASSESSMENT

After identifying and sampling ML and DL articles, and collecting all reviews, qualitative thematic analysis was performed to identify major and minor themes of reviewer critiques.

STATISTICAL TESTS

Descriptive statistics provided of article characteristics, and thematic review of major and minor themes.

RESULTS

Thirty-eight articles were sampled for thematic review: 24 (63.2%) focused on classical ML and 14 (36.8%) on DL. The overall acceptance rate of classical ML/DL articles was 28.9%, similar to the overall 2017-2019 acceptance rate of 23.1-28.1%. These articles resulted in 72 reviews analyzed, yielding a total 713 critiques that underwent formal thematic analysis consensus encoding. Ten major themes of critiques were identified, with 1-Lack of Information as the most frequent, comprising 268 (37.6%) of all critiques. Frequent minor themes of critiques concerning ML/DL-specific recommendations included performing basic clinical statistics such as to ensure similarity of training and test groups (N = 26), emphasizing strong clinical Gold Standards for the basis of training labels (N = 19), and ensuring strong radiological relevance of the topic and task performed (N = 16).

DATA CONCLUSION

Standardized reporting of ML and DL methods could help address nearly one-third of all reviewer critiques made.

LEVEL OF EVIDENCE

4 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;52:248-254.

Preoperative surgical risk stratification in osteosarcoma based on the proximity to the major vessels

Aims

The aim of this study was to determine the risk of local recurrence and survival in patients with osteosarcoma based on the proximity of the tumour to the major vessels.

Patients and Methods

A total of 226 patients with high-grade non-metastatic osteosarcoma in the limbs were investigated. Median age at diagnosis was 15 years (4 to 67) with the ratio of male to female patients being 1.5:1. The most common site of the tumour was the femur (n = 103) followed by tibia (n = 66). The vascular proximity was categorized based on the preoperative MRI after neoadjuvant chemotherapy into four types: type 1 > 5 mm; type 2 ≤ 5 mm, > 0 mm; type 3 attached; type 4 surrounded.

Results

Limb salvage rate based on the proximity type was 92%, 88%, 51%, and 0% for types 1 to 4, respectively, and the overall survival at five years was 82%, 77%, 57%, and 67%, respectively (p < 0.001). Local recurrence rate in patients with limb-salvage surgery was 7%, 8%, and 22% for the types 1 to 3, respectively (p = 0.041), and local recurrence at the perivascular area was observed in 1% and 4% for type 2 and 3, respectively. The mean microscopic margin to the major vessels was 6.9 mm, 3.0 mm, and 1.4 mm for types 1 to 3, respectively. In type 3, local recurrence-free survival with limb salvage was significantly poorer compared with amputation (p = 0.025), while the latter offered no overall survival benefit. In this group of patients, factors such as good response to chemotherapy or limited vascular attachment to less than half circumference or longitudinal 10 mm reduced the risk of local recurrence.

Conclusion

The proximity of osteosarcoma to major blood vessels is a poor prognostic factor for local control and survival. Amputation offers better local control for tumours attached to the blood vessels but does not improve survival. Limb salvage surgery offers similar local control if the tumour attachment to blood vessels is limited. Cite this article: Bone Joint J 2019;101-B:1024–1031.

Distinguishing bone and soft tissue infections mimicking sarcomas requires multimodal multidisciplinary team assessment

INTRODUCTION

The aims of this study were to report the presenting characteristics and identify how best to distinguish bone and soft-tissue infections that mimic sarcomas.

MATERIALS AND METHODS

A total of 238 (211 osteomyelitis and 27 soft-tissue infections) patients referred to a tertiary sarcoma multidisciplinary team with suspected sarcoma who were ultimately diagnosed with a bone or soft tissue infection were included. Data from a prospectively collated database was analysed retrospectively.

RESULTS

Of all possible bone and soft-tissue sarcoma referrals, a diagnosis of infection was made in 2.1% and 0.7%, respectively. Median age was 18 years in the osteomyelitis group and 46 years in the soft-tissue infection group. In the osteomyelitis group, the most common presenting features were pain (85.8%) and swelling (32.7%). In the soft-tissue infection group, the most common clinical features were swelling (96.3%) and pain (70.4%). Those in the soft-tissue group were more likely to have raised inflammatory markers. Radiological investigations were unable to discern between tumour or infection in 59.7% of osteomyelitis and 81.5% of soft-tissue infection cases. No organism was identified in 64.9% of those who had a percutaneous biopsy culture.

CONCLUSIONS

This study has highlighted that infection is frequently clinically indistinguishable from sarcoma and remains a principle non-neoplastic differential diagnosis. When patients are investigated for suspected sarcoma, infections can be missed due to falsely negative radiological investigations and percutaneous biopsy. As no single clinical, biochemical or radiological feature or investigation can be relied upon for diagnosis, clinicians should have a low threshold for tissue biopsy and discussion in a sarcoma multidisciplinary team meeting.

The impact of the Paris terrorist attacks on the mental health of resident physicians

BACKGROUND

On November 13, 2015, terrorist attacks took place in Paris. One hundred and twenty-nine people were immediately killed and 302 needed emergency care. Many resident physicians were on the front line of the medical response. Our aim was to report the frequency of symptoms of post-traumatic stress disorder (PTSD), anxiety and depression among resident physicians after the Paris terrorist attacks.

METHODS

Anonymous questionnaires, including the Impact of Event Scale- Revised (IES-R) and the Hospital Anxiety and Depression Scale (HADS), were emailed two months after the attacks to 2413 Parisian resident physicians. Exposure to the attacks was defined as having direct clinical contact with one of the victims up to one week after the attacks, being one of the victims, or having one among close relatives.

RESULTS

The questionnaire was completed by 680 (28.2%) residents. Eighty-four (12.4%) reported symptoms of PTSD (IES-R ≥ 33), 76 (11.2%) reported symptoms of anxiety (HADS anxiety score > 10) and 16 (2.4%) reported symptoms of depression (HADS depression score > 10). Exposed residents had higher IES-R scores than non-exposed residents (18.8 ± 16.6 versus 14.2 ± 12.0, p = 0.001), and 40 (18.5%) of them reported symptoms of PTSD, compared to 44 (9.5%) of the non-exposed residents (p = 0.001).

CONCLUSIONS

There was a high frequency of symptoms of mental distress among our respondents. Dedicated screening and care strategies must be considered in the event of new attacks.

Prognostic factors for local recurrence in extremity-located giant cell tumours of bone with pathological fracture

AIMS

The aim of this paper was to investigate the prognostic factors for local recurrence in patients with pathological fracture through giant cell tumours of bone (GCTB).

PATIENTS AND METHODS

A total of 107 patients presenting with fractures through GCTB treated at our institution (Royal Orthopaedic Hospital, Birmingham, United Kingdom) between 1995 and 2016 were retrospectively studied. Of these patients, 57 were female (53%) and 50 were male (47%).The mean age at diagnosis was 33 years (14 to 86). A univariate analysis was performed, followed by multivariate analysis to identify risk factors based on the treatment and clinical characteristics.

RESULTS

The initial surgical treatment was curettage with or without adjuvants in 55 patients (51%), en bloc resection with or without reconstruction in 45 patients (42%), and neoadjuvant denosumab, followed by resection (n = 3, 3%) or curettage (n = 4, 4%). The choice of treatment depended on tumour location, Campanacci tumour staging, intra-articular involvement, and fracture displacement. Neoadjuvant denosumab was used only in fractures through Campanacci stage 3 tumours. Local recurrence occurred in 28 patients (25%). Surgery more than six weeks after the fracture did not affect the risk of recurrence in any of the groups. In Campanacci stage 3 tumours not treated with denosumab, en bloc resection had lower local recurrences (13%), compared with curettage (39%). In tumours classified as Campanacci 2, intralesional curettage and en bloc resections had similar recurrence rates (21% and 24%, respectively). After univariate analysis, the type of surgical intervention, location, and the use of denosumab were independent factors predicting local recurrence. Further surgery was required 33% more often after intralesional curettage in comparison with resections (mean 1.59, 0 to 5 vs 1.06, 0 to 3 operations). All patients treated with denosumab followed by intralesional curettage developed local recurrence.

CONCLUSION

In patients with pathological fractures through GCTB not treated with denosumab, en bloc resection offers lower risks of local recurrence in tumours classified as Campanacci stage 3. Curettage or resections are both similar options in terms of the risk of local recurrence for tumours classified as Campanacci stage 2. The benefits of denosumab followed by intralesional curettage in these patients still remains unclear.

Risk factors for hemoptysis complicating 17-18 gauge CT-guided transthoracic needle core biopsy: multivariate analysis of 249 procedures

PURPOSE

We aimed to identify modifiable and nonmodifiable risk factors for hemoptysis complicating computed tomography (CT)-guided transthoracic needle biopsy.

METHODS

All procedures performed in our institution from November 2013 to May 2015 were reviewed. Hemoptysis was classified as mild if limited to hemoptoic sputum and abundant otherwise. Presence of intra-alveolar hemorrhage on postbiopsy CT images was also evaluated. Patient- and lesion-related variables were considered nonmodifiable, while procedure-related variables were considered modifiable.

RESULTS

A total of 249 procedures were evaluated. Hemoptysis and alveolar hemorrhage occurred in 18% and 58% of procedures, respectively, and were abundant or significant in 8% and 17% of procedures, respectively. Concordance between the occurrence of significant alveolar hemorrhage (grade ≥2) and hemoptysis was poor (κ=0.28; 95% CI [0.16-0.40]). In multivariate analysis, female gender (P = 0.008), a longer transpulmonary needle path (P = 0.014), and smaller lesion size (P = 0.044) were independent risk factors for hemoptysis. Transpulmonary needle-path length was the only risk factor for abundant hemoptysis with borderline statistical significance (P = 0.049).

CONCLUSION

The transpulmonary needle path should be as short as possible to reduce the risk of abundant hemoptysis during CT-guided transthoracic needle biopsy.

Naming Notes: Transitions from Free Text to Structured Entry

To practice medicine in the near future, health care providers in the USA need an information infrastructure they do not yet have. We offer a contribution from social science research to discussions of current medical records practices and how health care activity systems may be transformed by the advent of electronic health records. The goal of the paper is to set forth a framework that connects over-arching questions concerning medical informatics systems development with the practical, cultural and conceptual issues involved in transitions from handwritten and other free text documentation to structured entry of medical records to build patient profiles. The research is broadly framed by an interest in how reciprocal modifications of the design and use of an electronic health record are negotiated in an iterative prototyping project. It is conducted as part of a complex multi-disciplinary research and development effort to create an electronic health record prototype for use in the integrated health care delivery environment of the Southern California Kaiser Permanente Medical Care Program.

Shoulder Arthroplasty Imaging: What's New

Background

Shoulder arthroplasty, in its different forms (hemiarthroplasty, total shoulder arthroplasty and reverse total shoulder arthroplasty) has transformed the clinical outcomes of shoulder disorders. Improvement of general clinical outcome is the result of stronger adequacy of the treatment to the diagnosis, enhanced surgical techniques, specific implanted materials, and more accurate follow up. Imaging is an important tool in each step of these processes.

Method

This article is a review article declining recent imaging processes for shoulder arthroplasty.

Results

Shoulder imaging is important for shoulder arthroplasty pre-operative planning but also for post-operative monitoring of the prosthesis and this article has a focus on the validity of plain radiographs for detecting radiolucent line and on new Computed Tomography scan method established to eliminate the prosthesis metallic artefacts that obscure the component fixation visualisation.

Conclusion

Number of shoulder arthroplasties implanted have grown up rapidly for the past decade, leading to an increase in the number of complications. In parallel, new imaging system have been established to monitor these complications, especially component loosening.

Short, Medium and Long Term Complications After Total Anatomical Shoulder Arthroplasty

Total shoulder arthroplasty (TSA) is an effective approach for the treatment of a variety of clinical conditions affecting the shoulder, including osteoarthritis, inflammatory arthritis and osteonecrosis, and the number of TSA implanted has grown exponentially over the past decade. This review gives an update of the major complications, mainly infections, instability and loosening, encountered after TSA, based on a corpus of recent publications and a dynamic approach: The review focuses on the causes of glenoid loosening, which account for 80% of the complication, and underlines the importance of glenoid positioning in the recovery of early shouder function and in the long term survival rate of TSA.

Application of CRISPR/Cas9 to the study of brain development and neuropsychiatric disease

CRISPR/Cas9 technology has transformed our ability to manipulate the genome and epigenome, from efficient genomic editing to targeted localization of effectors to specific loci. Through the manipulation of DNA- and histone-modifying enzyme activities, activation or repression of gene expression, and targeting of transcriptional regulators, the role of gene-regulatory and epigenetic pathways in basic biology and disease processes can be directly queried. Here, we discuss emerging CRISPR-based methodologies, with specific consideration of neurobiological applications of human induced pluripotent stem cell (hiPSC)-based models.

Surgical Innovation in Sarcoma Surgery

The field of orthopaedic oncology relies on innovative techniques to resect and reconstruct a bone or soft tissue tumour. This article reviews some of the most recent and important innovations in the field, including biological and implant reconstructions, together with computer-assisted surgery. It also looks at innovations in other fields of oncology to assess the impact and change that has been required by surgeons; topics including surgical margins, preoperative radiotherapy and future advances are discussed.

Surveillance of intramedullary cartilage tumours in long bones

AIMS

The purpose of this study was to determine if clinical and radiological surveillance of cartilage tumours with low biological activity is appropriate.

PATIENTS AND METHODS

A total of 98 patients with an intramedullary cartilage neoplasm in a long bone met our inclusion criteria and were included in the study. These patients had undergone a total of 384 scans. Patients with radiological follow-up of more than three years (46 patients) were divided into two groups: an active group (11 patients) and a latent group (35 patients).

RESULTS

Active lesions had a total growth in all three planes that was > 6 mm, whilst latent lesions had < 6 mm of growth. Most latent lesions were heavily calcified: active lesions were calcified less than 50% (p = 0.025).

CONCLUSION

Clinico-radiological surveillance can identify growing cartilage lesions: MRI is the surveillance modality of choice. A CT scan is recommended, in addition, at presentation to assess the amount of calcification within the lesion. A first follow-up MRI is suggested one year from diagnosis. If the total growth in the cartilage lesion is > 6 mm, surgical treatment should be considered. Otherwise, a second surveillance scan can be performed at three years to determine further management. Cite this article: Bone Joint J 2016;98-B:1542-7.

A Practical Approach to Indeterminate and Cystic Renal Masses

Cystic renal masses are a common entity with a wide differential diagnosis encountered by the radiologist in daily practice. Their characterization relies on the Bosniak classification system that has been widely accepted by radiologists and urologists as a pertinent diagnostic and communication tool. It has been designed to separate cystic lesions requiring surgery (categories III and IV) from those that can be ignored and left alone (categories I and II) or followed (category IIF). Utilization of the Bosniak classification requires, first, previous identification of the cystic nature of a renal mass with the exception of very small lesions.

Development & automation of a novel [(18)F]F prosthetic group, 2-[(18)F]-fluoro-3-pyridinecarboxaldehyde, and its application to an amino(oxy)-functionalised Aβ peptide

2-[(18)F]-Fluoro-3-pyridinecarboxaldehyde ([(18)F]FPCA) is a novel, water-soluble prosthetic group. It's radiochemistry has been developed and fully-automated for application in chemoselective radiolabelling of amino(oxy)-derivatised RI-OR2-TAT peptide, (Aoa-k)-RI-OR2-TAT, using a GE TRACERlab FX-FN. RI-OR2-TAT is a brain-penetrant, retro-inverso peptide that binds to amyloid species associated with Alzheimer's Disease. Radiolabelled (Aoa-k)-RI-OR2-TAT was reproducibly synthesised and the product of the reaction with FPCA has been fully characterised. In-vivo biodistribution of [(18)F]RI-OR2-TAT has been measured in Wistar rats.

Stimuli-responsive cylindrical hydrogels mimic intestinal peristalsis to propel a solid object

The emerging field of soft robotics relies on soft, stimuli-responsive materials to enable load transport, manipulation, and mobility in complex unconstrained environments. These materials often need to replicate biological functionality such as muscle contractions and flexibility. Here we demonstrate a soft actuator prototype based on thermosensitive PNIPAAM hydrogels that can transport and manipulate objects. A hollow cylindrical hydrogel was selectively heated and cooled with Peltier devices to yield a traveling wave of shrinking and swelling akin to intestinal peristalsis. A 4 mm diameter bead was placed inside the cylinder and propelled 19.5 mm, equal to distance traveled by the peristaltic wave. We derived conditions that enable peristaltic transport as a function of transporter-cargo design parameters. We conclude that hydrogel-based peristaltic manipulators covering 2 orders of magnitude in stiffness (1-10(2) kPa) could transport cargo spanning 4 orders of magnitude in size (μm-m).

MR diagnosis of diaphragmatic endometriosis

PURPOSE

To evaluate magnetic resonance imaging (MRI) for diaphragmatic endometriosis diagnosis.

MATERIALS AND METHODS

Over a 2-year period, all diaphragmatic MRI performed in the context of diaphragmatic endometriosis were reviewed. Axial and coronal fat-suppressed T1- and T2-weighted sequences were analyzed by two independent readers for the presence of nodules, plaque lesions, micronodule clustering, or focal liver herniation. MR abnormalities were correlated to surgical findings in women surgically treated. Interobserver agreement was assessed by κ statistics.

RESULTS

Twenty-three women with diaphragmatic endometriosis criteria comprised the population; 14 had surgical confirmation and nine had symptoms relief with hormonal treatment. MRI sensitivity was 83 % (19/23; 95 % confidence interval [CI]: 68, 98) for reader 1 and 78 % (18/23; 95 % CI: 61, 95) for reader 2. Kappa value was 0.86 (95 % CI: 0.47, 1.00). Readers 1 and 2 detected 35 and 36 lesions, respectively, all right-sided and agreed for 32 lesions on the type, location, and signal. Lesions were mostly nodules (23/32, 72 %), predominantly posterior (28/32, 87.5 %) and hyperintense on T1 (20/32, 63 %). MRI was negative for both readers in 2 surgically treated patients with small nodules or isolated diaphragmatic holes.

CONCLUSION

MRI allows diaphragmatic endometriosis diagnosis with 78 to 83 % sensitivity and excellent interobserver agreement.

KEY POINTS

• MRI allows the diagnosis of diaphragmatic endometriosis with up to 83 % sensitivity. • Diaphragmatic endometriosis lesions are better depicted on fat-suppressed T1-weighted sequences. • Diaphragmatic lesions, mostly hyperintense nodules, are right-sided and predominantly posterior. • MRI can help in timely diagnosis of diaphragmatic endometriosis.