Abstract Background Effective diagnostic tools for prompt identification of high-risk locally advanced cervical cancer (LACC) patients are needed to facilitate early, individualized treatment. The aim of this work was to assess temporal changes in tumor radiomics (delta radiomics) from T2-weighted imaging (T2WI) during concurrent chemoradiotherapy (CCRT) in LACC patients, and their association with progression-free survival (PFS). Furthermore, to develop, validate, and compare delta- and pretreatment radiomic signatures for prognostic modeling. Methods A total of 110 LACC patients undergoing CCRT with MRI at baseline and mid-treatment were divided into training (cohortT: n = 73) and validation (cohortV: n = 37) cohorts. Radiomic features were extracted from tumors segmented on pre-CCRT and mid-CCRT T2WI and radiomic deltas (delta features) were computed. Two radiomic signatures for predicting PFS were constructed by least absolute shrinkage and selection operator (LASSO) Cox regression: Deltarad (from delta features) and Pre-CCRTrad (from pre-CCRT features). Prognostic performance of the radiomic signatures, 2018 International Federation of Gynecology and Obstetrics (FIGO) stage (I–IV), and baseline MRI-derived maximum tumor diameter (Tumormax: ≤2 cm; >2 and ≤ 4 cm; >4 cm) was evaluated by area under time-dependent receiver operating characteristics (tdROC) curves (AUC) in cohortT and cohortV (AUCT/AUCV). Mann–Whitney U tests assessed differences in radiomic delta features. PFS was evaluated using the Kaplan–Meier method with log-rank tests. Results Deltarad (AUCT/AUCV: 0.74/0.79) marginally outperformed Pre-CCRTrad (0.72/0.75) for predicting 5-year PFS, and both signatures clearly surpassed that of FIGO (0.61/0.61) and Tumormax (0.58/0.65). In total, four features within Deltarad and Pre-CCRTrad significantly differed in delta feature values between progressors and non-progressors, being consistently lower in progressors (p ≤ 0.03 for all). High Deltarad and Pre-CCRTrad radiomic scores were associated with poor PFS (p ≤ 0.04 for Deltarad in cohortT/Pre-CCRTrad in both cohorts; p = 0.11 for Deltarad in cohortV). Conclusions Delta- and pretreatment radiomic signatures equally allow early prognostication in LACC, outperforming FIGO stage and MRI-assessed maximum tumor diameter.

Despite major reforms of specialist training in the Nordic countries towards concrete learning outcomes and promoting active learning, most specialist courses continue to be based on lectures. We redesigned our mandatory 5-day course in clinical nuclear medicine (NM) that was last held in 2016 towards active learning. Thirty 1-h lectures were replaced with 10 thematic blocks of 3 h each. Each block was taught by a single teacher in a blend of short introductory lectures alternating with small groups of residents reading NM cases from our newly established national case library in diagnostic format. Due to COVID-19, the entire course in 2021 needed to be run on a videoconferencing system rather than in a computer laboratory as had been originally planned. At the end of the course, we conducted the same anonymized survey as in 2016. All 19 course participants responded. 74% fully agreed that the e-course format had been 'good'. One hundred per cent fully agreed that the practical exercises were 'useful' versus 50% in 2016 (p < 0.001). In their free text answers on the merits or downsides of e-learning, 12/12 respondents only mentioned advantages. Our newly established library of anonymized teaching cases within our national health network is an effective tool for organising courses based on active learning. Despite the change towards distance learning enforced by the pandemic, course participants reported the same high levels of satisfaction with active learning in small groups as in the earlier traditional lecture-based course format.

This study presents the diagnostic performance of four different preoperative imaging workups (IWs) for prediction of lymph node metastases (LNMs) in endometrial cancer (EC): pelvic MRI alone (IW1), MRI and [18F]FDG-PET/CT in all patients (IW2), MRI with selective [18F]FDG-PET/CT if high-risk preoperative histology (IW3), and MRI with selective [18F]FDG-PET/CT if MRI indicates FIGO stage ≥ 1B (IW4). In 361 EC patients, preoperative staging parameters from both pelvic MRI and [18F]FDG-PET/CT were recorded. Area under receiver operating characteristic curves (ROC AUC) compared the diagnostic performance for the different imaging parameters and workups for predicting surgicopathological FIGO stage. Survival data were assessed using Kaplan-Meier estimator with log-rank test. MRI and [18F]FDG-PET/CT staging parameters yielded similar AUCs for predicting corresponding FIGO staging parameters in low-risk versus high-risk histology groups (p ≥ 0.16). The sensitivities, specificities, and AUCs for LNM prediction were as follows: IW1—33

OBJECTIVES:To compare the diagnostic accuracy of preoperative 18F-FDG PET/CT and MRI tumor markers for prediction of lymph node metastases (LNM) and aggressive disease in endometrial cancer (EC). METHODS:Preoperative whole-body 18F-FDG PET/CT and pelvic MRI were performed in 215 consecutive patients with histologically confirmed EC. PET/CT-based tumor standardized uptake value (SUVmax and SUVmean), metabolic tumor volume (MTV), and PET-positive lymph nodes (LNs) (SUVmax > 2.5) were analyzed together with the MRI-based tumor volume (VMRI), mean apparent diffusion coefficient (ADCmean), and MRI-positive LN (maximum short-axis diameter ≥ 10 mm). Imaging parameters were explored in relation to surgicopathological stage and tumor grade. Receiver operating characteristic (ROC) curves were generated yielding optimal cutoff values for imaging parameters, and regression analyses were used to assess their diagnostic performance for prediction of LNM and progression-free survival. RESULTS:For prediction of LNM, MTV yielded the largest area under the ROC curve (AUC) (AUC = 0.80), whereas VMRI had lower AUC (AUC = 0.72) (p = 0.03). Furthermore, MTV > 27 ml yielded significantly higher specificity (74%, p < 0.001) and accuracy (75%, p < 0.001) and also higher odds ratio (12.2) for predicting LNM, compared with VMRI > 10 ml (58%, 62%, and 9.7, respectively). MTV > 27 ml also tended to yield higher sensitivity than PET-positive LN (81% vs 50%, p = 0.13). Both VMRI > 10 ml and MTV > 27 ml were significantly associated with reduced progression-free survival. CONCLUSIONS:Tumor markers from 18F-FDG PET/CT outperform MRI markers for the prediction of LNM. MTV > 27 ml yields a high diagnostic performance for predicting aggressive disease and represents a promising supplement to conventional PET/CT reading in EC. KEY POINTS:• Metabolic tumor volume (MTV) outperforms other 18F-FDG PET/CT and MRI markers for preoperative prediction of lymph node metastases (LNM) in endometrial cancer patients. • Using cutoff values for tumor volume for prediction of LNM, MTV > 27 ml yielded higher specificity and accuracy than VMRI> 10 ml. • MTV represents a promising supplement to conventional PET/CT reading for predicting aggressive disease in EC.

BACKGROUND:Radiology and nuclear medicine have traditionally been taught in a series of lectures and seminars concluded by an examination testing knowledge rather than skills. PURPOSE:To emphasize skills in the students' learning process, we developed and evaluated a new e-learning framework for teaching medical imaging. MATERIAL AND METHODS:The framework consists of electronic lectures, a learning management system (LMS), and a diagnostic viewing system. Students were to review positron emission tomography/computed tomography (PET/CT) examinations of five cases of lung cancer. The framework was evaluated in an objective structured clinical examination (OSCE) taken by 139 undergraduate students at the end of their third year, and in a comparative survey of two groups of 85 and 84 students in the fifth and sixth year who were taught the same oncology course with and without mandatory PET/CT exercises, respectively. RESULTS:Of the 139 third-year students, 134 (96%) passed the OSCE PET/CT station according to the predefined criteria. While 85/85 (100%) of the fifth-year students had taken exercises when they were mandatory, only 2/84 (2%) of the sixth-year students had reviewed the cases on a voluntary basis (P < 0.001). Of the 25 survey responders in the fifth year, 24 (96%) agreed that the mandatory PET/CT exercises had promoted their learning while the sixth-year students, whose course concluded with a multiple-choice examination, emphasized the utility of online lectures. CONCLUSION:The new e-learning framework teaches students basic competency in PET/CT navigation and interpretation and is associated with a high degree of student satisfaction.

281 Objectives: To compare the diagnostic accuracy of preoperative tumor markers derived from FDG PET/CT and MRI for the prediction of lymph node metastases (LNM) and aggressive disease in endometrial cancer (EC) patients. Methods: Preoperative whole-body FDG PET/CT and pelvic MRI were prospectively performed in 215 consecutive patients with histologically confirmed EC. The FDG PET/CT based tumor parameters maximum and mean standardized uptake value (SUVmax, SUVmean) and metabolic tumor volume (MTV) were analyzed together with the MRI based tumor volume (VMRI) and mean tumor apparent diffusion coefficient (ADCmean). Imaging parameters were explored in relation to surgicopathological stage and tumor grade. Receiver operating characteristic (ROC) curves were generated yielding optimal cut-offs for imaging parameters, and regression analyses were used to assess their diagnostic performance for prediction of LNM and outcome. Results: MTV and VMRI were the only imaging parameters significantly associated with deep myometrial invasion (p 27 ml and VMRI>10 ml yielded comparable sensitivity (81% for both), but MTV>27 ml had higher specificity (74% vs. 60%), accuracy (75% vs. 62%) and odds ratio (12.2 vs. 6.5) compared to VMRI>10 ml. Patients with higher SUVmean and MTV had significantly reduced recurrence/progression-free survival with univariate hazard ratios of 1.148 (p=0.03) and 1.003 (p=0.02), whereas high SUVmax and VMRI only tended to the same (p=0.12 and 0.18, respectively). Conclusions: Tumor markers derived from FDG PET/CT outperform MRI markers for the prediction of LNM and poor survival in EC. MTV>27 ml yielded high diagnostic performance for predicting aggressive disease and represents a promising supplement to conventional PET/CT reading in EC.

To explore quantitative metabolic and microstructural primary tumour parameters at pretreatment FDG-PET/CT and diffusion-weighted-magnetic resonance imaging (DW-MRI) in relation to clinical FIGO stage and outcome in uterine cervical cancer patients.

1772 Objectives In dynamic renography with 99mTc-MAG3, split renal function (SLF) is usually calculated using the area under the renogram 60 - 120 seconds after injection (Area method) [1]. An alternative approach is using the maximum slope of the upslope phase of the renogram (Slope method). We compared both methods against static scintigraphy with 99mTc-DMSA in the same patients. Methods We retrospectively identified all patients that had undergone dynamic MAG3 (0 - 36 min post injection; p.i.) and static DMSA scintigraphy (4 h p.i.) within 10 days between Jan 2006 and Dec 2014 in our PACS. Digital acquisitions were processed with Segami Oasis 1.9.3 (Segami Corp., Maryland/MD) using area and slope algorithms, respectively. For the purpose of this analysis, SLF was quantified only on posterior projections with bilateral semilunar regions for background correction. For each patient, the poorer functioning kidney on DMSA scintigraphy was analyzed. Data were collected and analyzed using MDCake and R [2]. Results 42 patients aged 47 yrs. (12, 74) (median age; interquartile range) with a serum creatinine of 71 mmol/l (48, 112) underwent both studies within 10 days. The slope algorithm correlated more closely with DMSA SLF than the area algorithm (median difference 0 vs. 2.8 %; p 5 % against DMSA) with the slope algorithm (29 %) than with the area algorithm (40 %; n. s., Fisher’s exact test). However, the slope algorithm was more susceptible to motion artifacts (n = 4 cases) and noisy curves due to poor renal function (n = 7). Conclusions In our preliminary analysis, split renal based on the slope algorithm correlates more closely with DMSA SLF than with the more established area algorithm. However, the slope algorithm may be more susceptible to artifacts.

The aim was to compare resource utilization across the four health trusts within the Western Norway Regional Health Authority since the establishment of positron emission tomography (PET) at Haukeland University Hospital in Bergen in 2009.Metadata from all PET examinations from 2009 to 2014 were automatically imported from the PET centre's central production database into a custom-developed database system, MDCake. A PET examination was defined as a procedure based on a single injection of radioactive tracer. The patients' place of residence and tentative diagnosis were coded based on the available clinical information.The total number of PET examinations increased from 293 in 2009 to 1616 in 2014. The number of PET examinations per year increased across all diagnostic groups, but plateaued for lung cancer, gastrointestinal cancer and malignant melanoma since 2013. The number of examinations per capita was evenly distributed between the three northern health trusts with an average of 1260 PET studies per million inhabitants in 2014. However, patients residing in the most southerly health trust received between 44% (2010) and 27% (2014; P<0·001, repeated measures ANOVA) fewer examinations per capita per year.Centralized PET in the Western Norwegian health region meets the current clinical demand for patients residing in the three northern health trusts while patients from the most southern health trust receive approximately 30% fewer PET examinations. Access to specialized health care should be monitored routinely in order to identify inequalities in referral patterns and resource utilization.