Radiological Review Research Articles

Incidental findings and safety events from magnetic resonance imaging simulation for head and neck radiation treatment planning: A single institution experience

PurposeHaving dedicated MRI scanners within radiation oncology departments may present unexpected challenges since radiation oncologists and radiation therapists are generally not trained in this modality and there are potential patient safety concerns. This study retrospectively reviews the incidental findings and safety events that were observed at a single institution during introduction of MRI sim for head and neck radiotherapy planning. MethodsConsecutive patients from March 1, 2020, to May 31, 2022, who were scheduled for MRI sim after having completed CT simulation for head and neck radiotherapy were included for analysis. Patients first underwent a CT simulation with a thermoplastic mask and in most cases with an intraoral stent. The same setup was then reproduced in the MRI simulator. Safety events were instances where scheduled MRI sims were not completed due to the MRI technologist identifying MRI-incompatible devices or objects at the time of sim. Incidental findings were identified during weekly quality assurance rounds as a joint enterprise of head and neck radiation oncology and neuroradiology. Categorical variables between completed and not completed MRI sims were compared using the Chi-Square test and continuous variables were compared using the Mann-Whitney U test with a p-value of < 0.05 considered to be statistically significant. Results148 of 169 MRI sims (88 %) were completed as scheduled and 21 (12 %) were not completed (Table 1). Among the 21 aborted MRI sims, the most common reason was due to safety events flagged by the MRI technologist (n = 8, 38 %) because of the presence of metal or a medical device that was not noted at the time of initial screening by the administrative coordinator. Patients who did not complete MRI sim were more likely to be treated for non-squamous head and neck primary tumor (p = 0.016) and were being treated post-operatively (p < 0.001). CT and MRI sim scans each had 17 incidental findings. CT simulation detected 3 cases of new metastases in lungs, which were outside the scan parameters of MRI sim. MRI sim detected one case of dural venous thrombosis and one case of cervical spine epidural abscess, which were not detected by CT simulation. ConclusionsRadiation oncology departments with dedicated MRI simulation scanners would benefit from diagnostic radiology review for incidental findings and having therapists with MRI safety credentialing to catch near-miss events.

#122 : Extrapolating Endometriosis Diagnosis Using Imaging and Machine Learning: The Imagendo Project

Background and Aims: Currently, it takes an average of 6.4 years to obtain a diagnosis for endometriosis. To address this delay, the IMAGENDO project combines ultrasounds (eTVUS) and Magnetic Resonance Images (eMRI) using Artificial Intelligence (AI). Our preliminary data has shown that a multimodal AI approach objectively assesses imaging data from eTVUS and eMRIs and improves diagnostic accuracy for endometriosis. Our first example shows how automated detection of Pouch of Douglas (POD) obliteration can be augmented by a novel multimodal approach. Aim: To improve eMRI detection of POD obliteration, by leveraging detection results from unpaired eTVUS data. Method: Retrospective specialist private and public imaging datasets of the female pelvis were obtained. After pre-training a machine learning model using 8,984 MRIs from a public dataset, we fine-tuned the algorithm using 88 private eMRIs, to detect POD obliteration. We then introduced another 749 unpaired eTVUSs to further improve our diagnostic model. Results: To resolve confounding problems with our eMRI datasets due to artefacts, mislabelling, and misreporting, we used model checking, student auditing and expert radiology review. Our results illustrated effective multimodal analysis methods which improved the POD obliteration detection accuracy from eMRI datasets. This model improved the Area Under the Curve (AUC) from 65.0% to 90.6%. Conclusion: We have been able to improve the accuracy of diagnosing endometriosis from eMRIs using a novel POD obliteration detection method. Our method extracts knowledge from unpaired eTVUSs and applies it to eMRI datasets. The detection of POD obliteration is automated from eMRI data. Combining images for corresponding endometriosis signs using algorithms, is the first step in improving the imaging diagnosis of endometriosis, when compared to surgery, and allows extrapolation of results when either imaging modality is missing. This will enable women to obtain a faster diagnosis, where adequate scanning is available, prior to undertaking surgery.

Association between Low Bone Mineral Density and Pain in a Prospective Cohort of Adults with Sickle Cell Disease: Preliminary Results from the SCD Bone Pain Study

Background: Osteonecrosis (ON), a prevalent skeletal complication of sickle cell disease (SCD), typically associates with severe chronic pain, frequent acute care utilization, and permanent disability. We previously showed that low bone mineral density (BMD) independently associates with hip ON and chronic pain in a pediatric SCD cohort. We now present preliminary data on the association between low BMD and pain in a prospective cohort of adults enrolled in the SCD Bone Pain Study (NCT05283148). Methods: Written informed consent was obtained from all participants, who were recruited from ambulatory adults with SCD seen at the University of California Davis Comprehensive Cancer Center. All participants underwent dual-energy X-ray absorptiometry (DXA) scans of their lumbar spine, left hip, and left forearm. Vertebral fractures were assessed by thoracolumbar morphometry in the DXA scanner. All participants also completed the Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) Pain Impact questionnaire. We used linear regression to evaluate the association between ASCQ-Me pain scores and low BMD (categorically defined as BMD Z-score ≤ -2 at any DXA site). We also used linear regression to determine the association between ASCQ-Me pain scores and continuous total hip and lumbar spine BMD Z-scores. Lastly, we evaluated the impact of other covariates on pain scores, with low BMD or BMD Z-scores included in the least absolute shrinkage and selection operator (LASSO, no shrinkage). Results: Thirty adults (median age 34.5 years [20-67 years]) completed the study between Nov 2022-Jul 2023. Baseline characteristics are summarized in Table 1. There was a borderline significant association between low BMD and lower (worse) pain scores (p=0.077). Continuous BMD Z-scores of the total hip (p=0.081) and lumbar spine (p=0.024) were independently associated with higher (better) pain scores. In addition to low BMD, only white blood cell count (WBC), indirect bilirubin, and vitamin D were identified as possible covariates (all had non-zero coefficients in LASSO analysis). Low BMD was significantly associated with pain (p=0.024), even after adjusting for WBC, indirect bilirubin, and vitamin D (Table 2). Similarly, we found that higher hip (p=0.059) and lumbar (p=0.027) BMD Z-scores were associated with higher (better) pain scores, despite adjusting for the same confounders. Discussion: We found low BMD in 12 of 30 (40%) adults enrolled in the SCD Bone Pain Study. Like other chronic hemolytic anemias, compensatory increased erythropoiesis leads to trabeculae degradation, cortical bone thinning, and eventual low bone mass. Lumbar vertebrae comprises mostly of trabecular bone, while the hip joint has mostly cortical bone. This might explain why mean lumbar BMD Z-scores were lower than hip BMD Z-scores (Table 1), and why lumbar spine BMD Z-scores directly and significantly correlated with pain scores (Table 2). These preliminary data suggest that pain is more prevalent in SCD adults with low BMD than those with normal BMD as we previously reported in a pediatric SCD cohort. Pain scores decrease (worsen) with increasing WBC, which suggests an inflammatory component to chronic SCD pain. Contrary to expectation, higher indirect bilirubin (a marker of increased hemolysis) significantly correlated with higher (better) pain scores. Similarly, higher vitamin D (a proxy for bone health) correlated with lower (worse) pain scores, though this association was non-significant. The reason(s) for these counterintuitive associations between pain scores, indirect bilirubin, and vitamin D levels is currently unknown. Limitations include a small sample size, though using the LASSO method for multivariate regression adjusted for this. Further, low BMD causality could not be determined at this time. Recruitment is ongoing with an enrollment target of 50 adults with SCD by Nov 2023. Analysis are ongoing to determine if SCD-modifying therapies will impact the association between low BMD and pain. Bone biomarker studies are also pending. Further, the thoracolumbar morphometry is still undergoing radiologic review, so we can further assess how vertebral compression fractures (i) correlate with pain scores, and/or (ii) attenuate the association between low BMD and pain. Identifying and treating risk factors for low BMD may alleviate bone pain and potentially improve quality of life for all people with SCD.

HPB P11 Hepatic vein reconstruction during hepatectomy – a feasible and underused technique?

Abstract Background Hepatic vein involvement can be a contraindication to resection of liver tumours. This study aimed to assess the feasibility, long term outcomes and vein patency among patients who underwent hepatic vein reconstruction during liver resections for liver tumour(s). Methods Retrospective analysis of patients who underwent circumferential hepatic venous reconstruction identified from a prospectively maintained database. Standard volumetric analysis was performed using software to estimate volumetry with and without hepatic venous reconstruction. Long term vein patency was established using review of available radiology. Results 15 patients underwent 17 venous reconstructions for colorectal liver metastases (n=13), cholangiocarcinoma (n=1) and hepatocellular carcinoma (n=1). The median FLR without and with venous reconstruction were 32 (range 18.0-74.5) and 96% (range 26.9-97.7) respectively; the median increase in FLR was 34% per patient. Venous patency was 89% at a median follow-up of 25 months (Range 1-53) with 2 graft thrombosis. No patient developed PHLF. Conclusions Hepatic venous reconstruction during liver resection is safe and feasible. It has the potential to expand the scope of liver resection and preserve liver and venous drainage if needed in the future.

Efficacy and safety of ripretinib vs. sunitinib in patients with advanced gastrointestinal stromal tumor previously treated with imatinib: A phase 2, multicenter, randomized, open-label study in China

AimA bridging study of INTRIGUE study to assess the efficacy and safety of ripretinib versus sunitinib as second-line treatment in Chinese GIST patients. MethodsThis was a phase 2, multicenter, randomized, open-label study in China. GIST patients previously treated with imatinib were randomized (1:1) to receive ripretinib 150 mg once daily (QD) by continuous dosing in 42-day cycles or sunitinib 50 mg QD in 42-day cycles (four weeks on/two weeks off). Primary endpoint was progression-free survival (PFS) by independent radiological review (IRR). ResultsBetween 6 December 2020 and 15 September 2021, 108 patients were randomized to receive ripretinib (n = 54) or sunitinib (n = 54) (all-patient [AP] intention-to-treat [ITT] population). Seventy patients had primary KIT exon 11 mutations (ripretinib, n = 35; sunitinib, n = 35; Ex11 ITT population). By data cut-off (20 July 2022), in AP ITT population, PFS by IRR was comparable between ripretinib and sunitinib arms (HR 0·99, 95 % CI 0·57, 1·69; nominal p = 0·92; median PFS [mPFS] 10·3 vs 8·3 months). In Ex11 ITT population, PFS by IRR was longer for ripretinib than sunitinib (HR 0·46, 95 % CI 0·23, 0·92; nominal p = 0·03; mPFS not reached in ripretinib arm and 4·9 months in sunitinib arm). Fewer patients experienced grade 3/4 treatment-related treatment-emergent adverse events with ripretinib (17%) versus sunitinib (56%). ConclusionsRipretinib demonstrated similar efficacy and a favorable safety profile versus sunitinib as second-line treatment in Chinese GIST patients. Furthermore, ripretinib provided greater clinically meaningful benefit versus sunitinib in patients with KIT exon 11 mutation.

RTID-08. A RANDOMIZED, MULTICENTER, DOUBLE-BLIND, PHASE 2B STUDY OF IGV-001, AN AUTOLOGOUS CELL IMMUNOTHERAPY WITH ANTISENSE OLIGO IMV-001 TARGETING IGF-1R, VS PLACEBO, IN NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS

Abstract Glioblastoma (GBM) is the most common primary brain malignancy in adults. Standard of care (SOC) for suspected GBM begins with maximal safe resection followed by adjuvant radiotherapy and temozolomide, and maintenance temozolomide. Imvax has developed the Goldspire™ platform to create IGV-001, an autologous biologic-device combination product for the treatment of newly diagnosed GBM (ndGBM). IGV-001 consists of autologous GBM tumor cells and an antisense oligonucleotide against IGF-1R mRNA (IMV-001), irradiated and administered via biodiffusion chambers implanted in the abdomen. Together, these components stimulate immunogenic cell death and antigen release. IGV-001 was well tolerated and multiple efficacy signals were observed in a Phase 1b study in patients with ndGBM, including significant improvements in progression-free survival (PFS), radiographic evidence of tumor response, and changes in immune response biomarkers. A Phase 2b randomized, multicenter, double-blind, placebo-controlled study has been initiated to assess the safety and efficacy of IGV-001 in patients with ndGBM (NCT04485949). After surgical resection, patients will be treated with IGV-001 or placebo followed by SOC. 25 US sites have been selected with a target enrollment of 93 patients (2:1 randomization) and the study is open to enrollment. Key inclusion criteria are 18 to 70 years of age, Karnofsky performance status score ≥ 70, diagnosis of GBM based on the treating neurosurgeon's best clinical judgement, confirmed measurable disease pre-operatively, tumor located in the supratentorial compartment, and adequate bone marrow and organ function. Key exclusion criteria include bihemispheric disease, multicentric disease, or treatment with Tumor Treating Fields prior to documented progression. The primary outcome is PFS, defined as the time from randomization to first progression, as determined by blinded central radiology review, or death. Secondary outcomes include overall survival, defined as the time from randomization to death due to any cause, and safety.

CTNI-73. ALLIANCE A071601: PHASE II TRIAL OF BRAF/MEK INHIBITION IN NEWLY DIAGNOSED PAPILLARY CRANIOPHARYNGIOMAS

Abstract BACKGROUND Craniopharyngiomas, primary brain tumors of the pituitary-hypothalamic axis, can cause significant clinical sequelae. Treatment using surgery, radiation, or both often entails significant morbidity. In prior work, we demonstrated that ninety-five percent of papillary craniopharyngiomas (PCP) harbor BRAF V600E mutations (Brastianos et al. Nature Genetics 2014). In this multicenter National Cancer Institute cooperative group trial (Alliance A071601), we evaluated the safety and efficacy of BRAF/MEK inhibition in patients with PCP without prior irradiation. METHODS Eligible patients, with measurable disease and whose PCP screened positively for BRAF mutations, without prior radiation, received the BRAF/MEK inhibitor combination vemurafenib/cobimetinib in 28-day cycles. The primary endpoint of objective response rate at 4 months based on centrally determined volumetric data was evaluated in 16 patients on this single arm phase 2 trial. RESULTS Based on volumetric response criteria by central radiology review, 15 of 16 patients (94%; 95% CI: 70% to 100%) had a durable objective partial response to therapy. Thus, this study met primary endpoint for overall response rate. The median tumor reduction was 91% (range of 68% to 99%). Median follow-up was 22 months (95% CI: 19 to 30 months) and median number of treatment cycles was 8. Median progression-free survival and duration of response were not yet reached. Three patients progressed during follow-up after therapy was discontinued; none have died. The sole non-responder stopped treatment after eight days due to toxicity. Grade 3 toxicities at least possibly related to treatment occurred in 12 patients (rash in 6 patients). Grade 4 toxicities were observed in two patients: hyperglycemia (n=1) and increased creatine phosphokinase (n=1). Three patients discontinued treatment for adverse events. CONCLUSIONS Our study indicates that BRAF/MEK inhibitors are a safe and effective treatment for PCP without prior irradiation. Support: U10CA180821, U10CA180882; U24CA196171, U10CA180868 (NRG); Genentech; . ClinicalTrials.gov Identifier: NCT03224767.

Zygmunt Grudziński, 1870-1929.

This history page in the series "Leaders in MSK Radiology" is dedicated to the memory and achievements of Zygmunt Grudziński, Polish radiologist at the University of Warsaw and founder of the Polish Society of Radiology and Polish Radiological Review, the first radiology journal.

Influence of Tumor Cavitation on Assessing the Clinical Benefit of Anti-PD1 or PD-L1 Inhibitors in Advanced Lung Squamous Cell Carcinoma

PurposeA considerable portion of lung squamous cell cancer (LUSC) displays radiographic signs of cavitation. The cavitation of lesions is not accounted for in the prevailing Evaluation Criteria of Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 or iRECIST in lung cancer. We hypothesized that cavitation might alter response assessment in these patients. Patients and MethodsWe performed a retrospective radiologic review of 785 patients with stage IV LUSC treated with PD-1/PD-L1 antibody combined with platinum-based doublet chemotherapy. 131 patients exhibited cavitation lesions pre- or after-treatment. Response was assessed by RECIST v1.1 and a modified Evaluation Criteria in Solid Tumors (mRECIST) guidelines in which the longest diameter of any cavity was subtracted from the overall longest diameter of that lesion to measure target lesions. The response rate and PFS and OS between mRECIST and RECIST v1.1 were compared. Survival curves of different response categories in each criterion were prepared using the method of Kaplan-Meier and log-rank tests. Weighted κ statistics were used to assess interobserver reproducibilities and to compare response rates. The chi-square test confirmed the relationship between PD-L1 expression and post-treatment cavitation. ResultsNotable cavitation of pulmonary lesions was seen in 16.7% of 785 patients treated with immunotherapy combined with platinum-based chemotherapy. Using the mRECIST for response assessment resulted in a higher response rate than RECIST v1.1 (66% vs. 57%). mRECIST might better identify patients with PFS and OS benefits who have cavitation. The chi-square test revealed a marginally significant difference between PD-L1 expression and tumor cavitation. Interobserver reproducibility of mRECIST for tumor cavitation evaluation was acceptable (the weighted k coefficients for mRECIST criteria was 0.821). ConclusionCavitation lesions at baseline and after checkpoint treatment are common in LUSC patients. mRECIST records a significantly higher response rate than RECIST for these LUSC patients. Response assessment might be improved by incorporating cavitation into volume assessment for target lesions. These results may inform further modifications to RECIST V1.1 to better reflect efficacy with immunotherapy.

Optimizing disease progression assessment using blinded central independent review and comparing it with investigator assessment in the PRIMA/ENGOT-ov26/GOG-3012 trial: challenges and solutions

ObjectiveProgression-free survival is an established clinically meaningful endpoint in ovarian cancer trials, but it may be susceptible to bias; therefore, blinded independent centralized radiological review is often included in trial...

Modified response evaluation criteria in solid tumors: A better response evaluation criteria for patients with non-squamous non-small cell lung cancer after bevacizumab treatment.

Cavitation of lesions is common in non-squamous non-small cell lung cancer (non-squamous-NSCLC) patients treated with vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFRIs). However, traditional response evaluation criteria in solid tumors (RECIST) do not take cavitation into consideration and may no longer be accurate for potentially reflecting the real clinical efficacy of anti-vessel growth therapy. Here, we aimed to optimize the traditional RECIST version 1.1 by adding cavitation into the evaluation criteria. We performed a post-hoc radiologic review of 517 patients in a phase III clinical trial of bevacizumab biosimilar (SIBP04) combined with chemotherapy for the treatment of non-squamous NSCLC. Tumor responses were assessed by RECIST1.1 and mRECIST criteria (modified RECIST, a novel alternate method where the longest diameter of the cavity was subtracted from the overall longest diameter of that lesion to measure target lesions), respectively, and correlated with clinical outcomes. Cavitations of pulmonary lesions were seen in nine (2%) patients at baseline, and 97 (19%) during treatment. The use of mRECIST resulted in an alteration of the response category. For patients with post-therapy cavitation, the objective response rate was 56% using RECIST1.1 and 67% by mRECIST. In addition, the survival rates between partial response, stable disease, and progressive disease when the mRECIST was applied were significantly different (p<0.05), while RECIST1.1 failed to show survival differences (p=0.218). For patients with post-therapy cavitation, mRECIST exhibited higher predictability of survival than RECIST1.1. Response assessment might be improved by incorporating cavitation into assessment, potentially altering outcomes of key clinical efficacy parameters.

The Breast-Imaging Operations, Practices and Systems Inventory: A framework to examine mammography facility effects on screening in rural communities.

Develop and test a measurement framework of mammogram facility resources, policies, and practices in Appalachia. Survey items describing 7 domains of imaging facility qualities were developed and tested in the Appalachian regions of Kentucky, Ohio, Pennsylvania, Virginia, and West Virginia. Medicare claims data (2016-2018) were obtained on catchment area mammogram services. Construct validity was examined from associations with facility affiliation, community characteristics, mammogram screening uptake, and market reach. Analyses were performed with t-tests and ANOVA. A total of 192 (of 377) sites completed the survey. Five factors were initially selected in exploratory factor analysis (FA) and refined in confirmatory FA: capacity, outreach & marketing, operational support, radiology review (NNFI = .94, GFI = 0.93), and diagnostic services (NNFI = 1.00, GFI = 0.99). Imaging capacity and diagnostic services were associated with screening uptake, with capacity strongly associated with catchment area demographic and economic characteristics. Imaging facilities in economically affluent versus poorer areas belong to larger health systems and have significantly more resources (P < .001). Facilities in economically distressed locations in Appalachia rely more heavily on outreach activities (P < .001). Higher facility capacity was significantly associated (P < .05) with larger catchment area size (median split: 48.5vs 51.6), mammogram market share (47.4vs 52.7), and screening uptake (47.6vs 52.4). A set of 18 items assessing breast imaging services and facility characteristics was obtained, representing policies and practices related to a facility's catchment area size, market share, and mammogram screening uptake.

Primary and Periprosthetic Distal Femur Fractures in Older Adults: No Difference in 12-Month Mortality and Patient-Reported Outcomes.

To compare fracture incidence, mortality, and patient-reported health outcomes at 6 and 12 months postinjury between primary and periprosthetic distal femur fractures in older adults. A registry-based cohort study was conducted including all adults 70 years of age or older registered by the Victorian Orthopaedic Trauma Outcomes Registry who experienced a primary or periprosthetic distal femur fracture between 2007 and 2017. Outcomes included mortality and health status (Three-Level European Quality of Life-Five Dimensions Scale [EQ-5D-3L]) collected at 6 and 12 months postinjury. All distal femur fractures were confirmed by radiological review. Multivariable logistic regression was conducted to report associations between fracture type and mortality and health status. A final cohort of 292 participants was identified. Overall mortality for the cohort was 29.8%, and no significant differences were found in mortality rate or EQ-5D-3L outcomes between fracture types (ie, primary vs. periprosthetic). A large proportion of participants reported problems across all EQ-5D-3L domains at 6 and 12 months postinjury, with slightly worse outcomes in the primary fracture group. This study reports high mortality and poor 12-month outcomes in an older adult cohort with both periprosthetic and primary distal femur fractures. Given these poor outcomes, fracture prevention and a greater focus on long-term rehabilitation is needed in this cohort. In addition, the involvement of an ortho-geriatrician should be considered as a routine component of care. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Brown Syndrome or Superior Oblique Tendon Sheath Syndrome: Radiologic Imaging Characteristics and Literature Review

Brown syndrome is the inability to gaze upward beyond the horizontal level while adducting the eye due to an abnormality of the superior oblique tendon sheath complex. It is a rare extraocular muscular disorder, and its imaging is infrequently seen in radiologic practice. This article presents clinical characteristics and imaging of 5 patients with Brown syndrome and reviews the radiologic literature available, to familiarize the readers with its imaging findings.

Transcallosal approach and post-operative subdural collections: 12-year paediatric neurosurgery tertiary centre experience.

Following transcallosal surgery for tumour resection, the formation of convexity or interhemispheric subdural cerebrospinal fluid collections may lead to clinical deterioration and may influence decision-making with regards to additional interventions. The aim of this study was to determine the incidence, risk factors, and management of subdural collections following the transcallosal approach in a paediatric cohort. A retrospective case note and radiological review of all children who underwent transcallosal surgery for intraventricular and thalamic tumours was carried out covering a 12-year period (2012-2023) in a single-centre tertiary paediatric neurosurgery unit. Parameters including demographics and clinical information including lesion location, pathology, extent of resection, need for and type of shunt required, as well as depth, laterality, and location of the collection were analysed prior to shunting, and at approximately 3 weeks, 3 months, and latest follow-up available post-operatively in order to further elucidate the natural history of these subdural collections and their clinical significance. Sixty-four cases satisfied the inclusion criteria of transcallosal surgery for tumour resection; 13 did not have adequate post-operative imaging and were excluded. Of the remaining 51 cases, there were 32 children (63%) with post-operative CSF subdural collections, of which 59% were ipsilateral, with the remainder showing bilateral distribution. The overall shunt insertion rate was 25.5% (12 ventriculoperitoneal and 1 subdural-peritoneal shunt) at 3 months, with a mean time to shunting of 19 days post-operatively. Children who developed post-operative subdural collections had a higher rate of shunting, at 37.5%, compared to 5.2% in those who did not. Pre- and post-operative hydrocephalus and subtotal resection were identified as risk factors for development of subdural collections post-operatively. Subdural collections showed a natural course of reduction and regression over follow-up, with the exception of 3 children where they persisted or increased over time; although none of these required shunting. Those children who underwent shunt insertion showed greater regression in the size of the subdural collection over time compared to the non-shunted group. In this paediatric cohort, 25.5 % of children required insertion of a shunt by 3 months following transcallosal surgery. Pre- and post-operative hydrocephalus and subtotal tumour resection were risk factors for development of subdural collections post-operatively.

External validation, radiological evaluation, and development of deep learning automatic lung segmentation in contrast-enhanced chest CT

ObjectivesThere is a need for CT pulmonary angiography (CTPA) lung segmentation models. Clinical translation requires radiological evaluation of model outputs, understanding of limitations, and identification of failure points. This multicentre study aims to develop an accurate CTPA lung segmentation model, with evaluation of outputs in two diverse patient cohorts with pulmonary hypertension (PH) and interstitial lung disease (ILD).MethodsThis retrospective study develops an nnU-Net-based segmentation model using data from two specialist centres (UK and USA). Model was trained (n = 37), tested (n = 12), and clinically evaluated (n = 176) on a diverse ‘real-world’ cohort of 225 PH patients with volumetric CTPAs. Dice score coefficient (DSC) and normalised surface distance (NSD) were used for testing. Clinical evaluation of outputs was performed by two radiologists who assessed clinical significance of errors. External validation was performed on heterogenous contrast and non-contrast scans from 28 ILD patients.ResultsA total of 225 PH and 28 ILD patients with diverse demographic and clinical characteristics were evaluated. Mean accuracy, DSC, and NSD scores were 0.998 (95% CI 0.9976, 0.9989), 0.990 (0.9840, 0.9962), and 0.983 (0.9686, 0.9972) respectively. There were no segmentation failures. On radiological review, 82% and 71% of internal and external cases respectively had no errors. Eighteen percent and 25% respectively had clinically insignificant errors. Peripheral atelectasis and consolidation were common causes for suboptimal segmentation. One external case (0.5%) with patulous oesophagus had a clinically significant error.ConclusionState-of-the-art CTPA lung segmentation model provides accurate outputs with minimal clinical errors on evaluation across two diverse cohorts with PH and ILD.Clinical relevanceClinical translation of artificial intelligence models requires radiological review and understanding of model limitations. This study develops an externally validated state-of-the-art model with robust radiological review. Intended clinical use is in techniques such as lung volume or parenchymal disease quantification.Key Points• Accurate, externally validated CT pulmonary angiography (CTPA) lung segmentation model tested in two large heterogeneous clinical cohorts (pulmonary hypertension and interstitial lung disease).• No segmentation failures and robust review of model outputs by radiologists found 1 (0.5%) clinically significant segmentation error.• Intended clinical use of this model is a necessary step in techniques such as lung volume, parenchymal disease quantification, or pulmonary vessel analysis.Graphical

Incidence, Radiologic and Dosimetric Parameters Associated with Radiation Induced Breast Lymphedema

Radiation induced breast lymphedema (BL) is an underreported but common finding. This study aimed to report the incidence of clinical BL and investigate the radiologic and dosimetric parameters associated with higher risk of BL. This IRB approved study included women with breast cancer who underwent breast conservative surgery followed by adjuvant radiation therapy between 2019 and 2021 at our institution. We reviewed the eligible patients' charts for incidence of clinical BL resulting in symptoms and requiring physical therapy referral. Thickness of the skin at defined center and bottom points of the breast was measured for patient' baseline and follow up mammograms. Dosimetric parameters were imported from patients' radiation plans including mean, maximum doses, and volumes receiving 20, 30, 40, & 50 Gy (V20, V30, V40, & V50), of the whole breast (WB), breast_eval (BE), and breast skin (BS) (defined as the superficial 5 mm of the skin). A chi-square test was used to test the association between clinical BL and radiation treatment regimens and beam energies and the association of skin thicknesses between those who had clinical BL and those who did not. A Wilcoxon rank sum test was used to test the association of the dosimetric parameters with clinical BL. We identified 268 patients who were eligible for the study. After chart and radiologic review, 119 patients had complete records available and were included in this study. Twenty-nine patients (24.4%) of the patients presented with symptomatic BL. Most patients (68%) received hypofractionated (42.56 Gy with or without 10 Gy boost), while 25% received conventional and 7% received ultra-hypofractionated radiotherapy. There was no association between the fractionation and incidence of BL (p = 0.4). There was no association between breast size and BL (mean 1065 cc vs 1232 cc, p = 0.35). There was significant association between BL and BS V30 (142cc vs 162 cc, p = 0.02), and BS V40 (82 cc vs 102 cc, p = 0.02), and a trend towards significant association with BS V20 (172cc vs. 193cc, p = 0.08), BS V50 (8 cc vs. 16 cc, p = 0.06). There was no significant association between BL and BS mean dose (36.9 Gy vs 39 Gy p = 0.11), or BS max dose (53.9 Gy vs 54.1 Gy, p = 0.21). None of the dosimetric parameters of WB and BE had significant association with clinical BL. Utilizing ROC analysis, there was significant association between clinical BL and the change of baseline mammogram breast skin thickness and skin thickness at 6 months follow up mammograms (+13 mm center point p = 0.04, +9 mm bottom point p<0.5), and at 12 months mammograms (+15 mm center point p<0.5, +11 mm bottom point p<0.5). Almost 1 in 4 women experienced radiation induced BL in our cohort. BS V30 & V40 are significantly associated with higher risk of BL. There was significant association between increased skin thickening in 6- and 12-months follow up mammograms and BL. Further analysis will follow to assess the association between surgical and clinical characteristics and BL.

Feasibility and safety of a non-operative clinical strategy for radiologically diagnosed low grade anterior mesial temporal tumours in the absence of a histological diagnosis

Background Although resection of mesial temporal lobe lesions can be achieved with relatively low morbidity, resective surgery is not without risk. Whilst many lesions found in the anterior mesiotemporal lobe are low-grade entities, transforming and high-grade lesions have also been demonstrated. We investigate the feasibility of utilising serial quantitative volumetric imaging, to determine if a strategy of imaging surveillance can be safely employed for the management of radiologically diagnosed anterior mesial temporal low-grade tumours without a confirmed histological diagnosis. Methods A retrospective case-note and radiology review design were utilised. The primary presenting symptomatology was recorded together with the efficacy of symptomatic control. Volumetric analysis of MRI images was performed using Brainlab software. Pre- and post-operative neuropsychological data were analysed. Results 35 patients were identified with a radiological diagnosis of a low-grade anterior mesial temporal lobe tumour. Of these, 29% (n = 10) underwent surgical resection. For the whole cohort, the mean tumour volume at diagnosis was 6.5cm3, with a mean volumetric expansion of 1.4% per month. A significant difference was found between the volumetric expansion rate of those that underwent surgical treatment and those that did not (4.9% per month vs 0.06% per month, p < .01). Of those cases that did not undergo surgical resection, no significant difference was seen between the initial diagnostic volume and the volume at the time of their most recent interval surveillance scan (p = .97). New onset epilepsy was significantly associated with a requirement for eventual surgical tumour resection; relative risk = 6.25, 95% CI = 1.5–25.9, p = .0114. Conclusion Where medical seizure control is adequate, we suggest that conservative management is feasible even in the absence of a confirmed histological diagnosis. However, in patients aged over 50 years with new onset epilepsy, a lower threshold for intervention should be considered.

Anterior mediastinal masses in children: A radiologic review by ChatGPT

Anterior mediastinal kitleler (AMM'ler), çocuklarda nadir olmakla birlikte, yaşamı tehdit eden komplikasyon potansiyelleri nedeniyle önemli bir risk oluşturmaktadır. Ön mediasten - sternum ve perikard arasındaki bağ dokusu, lenfatik yapılar ve timus bezi ile dolu boşluk - içinde konumlanan bu kitleler, çok çeşitli klinik belirtilerle kendini gösterir. Hızlı tanı ve uygun klinik yaklaşım kritik öneme sahiptir. Bu derleme, özellikle "ChatGPT" (OpenAI tarafından GPT-3.5 mimarisi üzerine inşa edilmiştir) kullanılarak, çocuklarda anterior mediastinal kitlelerin AI chatbot tarafından oluşturulan bir keşfini sunmaktadır. Nihai metin, GPT-4 sürümü aracılığıyla bir dil düzenlemesinden ve intihal kontrolünden geçti.

1027 Small Bite vs Big Bite Closure Technique in Elective Oesophagectomy Patients

Abstract Aim After primary closure of a midline laparotomy wounds the estimated incisional hernia incidence can be as high as 25%. For many years large bite closure has been the standard in mainstream surgical training. Evidence has emerged to suggest small bite closure may be superior. We looked to examine the incidence of incisional hernias for elective oesophagectomies in one centre where both small bite and large bite techniques are performed. Method A retrospective analysis of 117 patients was performed. Follow up was for a maximum of five years and involved a combination of radiological and clinical reviews. Primary outcomes were defined as incisional hernia rates &amp; wound infections. Patient risk factors were recorded including age, co-morbidities such as cardiovascular or renal disease, diabetes, smoking, weight, steroid use and post-op complications. Results 74 patients had big bite closures and 38 had small bite closures. Overall there were 6 incisional hernias, 3 in each group (7.8% vs 4%, p-value 0.2). There were higher rates of wound infection in the small bite groups but again this failed to reach significance (7.9% vs 2.7% p-value 0.11). Conclusions Overall both outcomes are lower than the national averages which may explain the difficulty reaching significance. However, the results do suggest there may be other factors involved contributing to outcomes between small bite and big bite closure including operator familiarity.