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Additional file 1: Figure S1. Duration of symptoms at presentation, cohort 2019 versus 2020. Table S1. Comparison of patients with uncomplicated appendicitis for 2019 pre-COVID cohort vs. 2020 COVID cohort. Table S2. Comparison of patients with complicated appendicitis and with symptoms for more than 24 h, 2019 pre-COVID cohort versus 2020 COVID cohort. Table S3. Comparison of patients with an age of 60 years or higher of the 2019 pre-COVID cohort and 2020 COVID cohort. Table S4. Comparison of conservatively treated patients with appendicitis, 2019 pre-COVID cohort versus 2020 COVID cohort. Table S5. Comparison of conservatively treated patients by final (imaging) diagnosis and imaging modality, 2019 pre-COVID cohort versus 2020 COVID cohort. Table S6. COVID-19 positive appendicitis patients.

Background A challenge in imaging research is a diagnostic classification of study participants. We hypothesised that a structured approach would be efficient and that classification by medical students, residents, and an expert panel whenever necessary would be as valid as classification of all patients by experts. Methods OPTIMACT is a randomised trial designed to evaluate the effectiveness of replacing chest x-ray for ultra-low-dose chest computed tomography (CT) at the emergency department. We developed a handbook with diagnostic guidelines and randomly selected 240 cases from 2,418 participants enrolled in OPTIMACT. Each case was independently classified by two medical students and, if they disagreed, by the students and a resident in a consensus meeting. Cases without consensus and cases classified as complex were assessed by a panel of medical specialists. To evaluate the validity, 60 randomly selected cases not referred to the panel by the students and the residents were reassessed by the specialists. Results Overall, the students and, if necessary, residents were able to assign a diagnosis in 183 of the 240 cases (76% concordance; 95% confidence interval [CI] 71–82%). We observed agreement between students and residents versus medical specialists in 50/60 cases (83% concordance; 95% CI 74–93%). Conclusions A structured approach in which study participants are assigned diagnostic labels by assessors with increasing levels of medical experience was an efficient and valid classification method, limiting the workload for medical specialists. We presented a viable option for classifying study participants in large-scale imaging trials (Netherlands National Trial Register number NTR6163).

Additional file 1: Supplemental material 1. Diagnostic handbook. Supplemental material 2. Calculations of the reduction of working hours for medical specialists set against the hours of students and residents. Supplemental material 3. Reasons for disagreement between students. Supplemental material 4. Members of the OPTIMACT Study Group. Supplemental Table S1. Inter-observer agreement between students for specific diagnostic labels in 240 cases. Supplemental Table S2. Classification by the expert panel in 60 validation cases. Supplemental Table S3. Inter-observer agreement between members of the expert panel for specific diagnostic labels in 60 validation cases.

Phosphorus spectroscopy (31P) at 7T (300 MHz) enables clinically-relevant spatial resolutions and time scales with high potential for monitoring response to cancer treatment. However, at 7T collecting a radiological-grade anatomical image of the liver—which is required for performing localized 31P spectroscopy—presents a challenge. Unlike lower field-strength scanners, there is no body coil in the bore of the 7T and despite inadequate penetration depth (ABBREVIATIONS(PDE)Phosphodiester(GPE)Glycerophosphoethanolamine(GPC)Glycerophosphocholine(PME)Phosphomonoesther(PC)Phosphocholine(PE)Phosphoethanalomine(PI)Inorganic Phosphate(PCR)Phosphocreatine(PTC)Phophotidylcholine(CSI)Chemical Shift Imaging(GE)Gradient Echo(L)Left(R)Right(H)Head(F)Foot(A)Anterior(P)Posterior(TR)Repetition Time(TE)Echo Time

Appendix 3. Patient information folder short version. (PDF 42Â kb)

Appendix 1. SPIRIT OPTIMACT checklist. (PDF 56Â kb)

Appendix 2. Patient information folder regular version. (PDF 61Â kb)

Inclusion of suspicious pathological lymph nodes, stents and fiducials in the delineations. (PDF 279 kb)

Questionnaire. (PDF 258 kb)

Data of CTV and iCTV. (PDF 464 kb)

Patients with colorectal cancer are frequently presented with liver metastases for which (partial) resection is often the best therapy. However, the future remnant liver, the remaining part of the liver after resection, should allow adequate liver function to avoid liver failure. This thesis presents novel methods for the accurate voxel-wise estimation of the future remnant liver’s function based on pharmacokinetic modeling of dynamic contractenhanced (DCE)MRI. The methods comprise a variety of novel techniques for DCE-MRI of the liver: 1) 4D registration of the DCE series; 2) delineation of the liver, the liver vasculature and the liver’s anatomical segments; 3) pharmacokinetic (PK) modeling of the perfusion based on the intra-cellular contrast agent Gd-EOB-DTPA (Primovist); 4) assessment of the relation between DCE-MRI and hepatobiliary scintigraphy (HBS). Spatial alignment of the voxels in the 4D DCE-MRI is an important requirement for PK modeling. We exploit the proximity of deformation fields to sequentially register images in an ordered fashion. The global liver displacement helps in predicting the deformation ‘tendency’ along the time axis. The deformation tendency allows us to obtain a better starting point for the registration. Such a method aims to start the registration optimization close to the optimum and avoid getting trapped in a local minimum. We apply a liver-specific contrast agent, due to which the liver shows