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Objectives To investigate sources of variation in a multicenter rectal cancer MRI dataset focusing on hardware and image acquisition, segmentation methodology, and radiomics feature extraction software. Methods T2W and DWI/ADC MRIs from 649 rectal cancer patients were retrospectively acquired in 9 centers. Fifty-two imaging features (14 first-order/6 shape/32 higher-order) were extracted from each scan using whole-volume (expert/non-expert) and single-slice segmentations using two different software packages (PyRadiomics/CapTk). Influence of hardware, acquisition, and patient-intrinsic factors (age/gender/cTN-stage) on ADC was assessed using linear regression. Feature reproducibility was assessed between segmentation methods and software packages using the intraclass correlation coefficient. Results Image features differed significantly (p Conclusions Significant variations are present in multicenter MRI data, particularly related to differences in hardware and acquisition, which will likely negatively influence subsequent analysis if not corrected for. Segmentation variations had a minor impact when using whole volume segmentations. Between software packages, higher-order features were less reproducible and caution is warranted when implementing these in prediction models. Key Points • Features derived from T2W-MRI and in particular ADC differ significantly between centers when performing multicenter data analysis. • Variations in ADC are mainly (> 60%) caused by hardware and image acquisition differences and less so ( • Features derived using different image segmentations (expert/non-expert) were reproducible, provided that whole-volume segmentations were used. When using different feature extraction software packages with similar settings, higher-order features were less reproducible.

PURPOSE: The sigmoid take-off (STO) was recently introduced as a preferred landmark, agreed upon by expert consensus recommendation, to discern rectal from sigmoid cancer on imaging. Aim of this study was to assess the reproducibility of the STO, explore its potential treatment impact and identify its main interpretation pitfalls.METHODS: Eleven international radiologists (with varying expertise) retrospectively assessed n = 155 patients with previously clinically staged upper rectal/rectosigmoid tumours and re-classified them using the STO as completely below (rectum), straddling the STO (rectosigmoid) or completely above (sigmoid), after which scores were dichotomized as rectum (below/straddling STO) and sigmoid (above STO), being the clinically most relevant distinction. A random subset of n = 48 was assessed likewise by 6 colorectal surgeons. .RESULTS: Interobserver agreement (IOA) for the 3-category score ranged from κ0.19-0.82 (radiologists) and κ0.32-0.72 (surgeons), with highest scores for the most experienced radiologists (κ0.69-0.76). Of the 155 cases, 44 (28%) were re-classified by ≥ 80% of radiologists as sigmoid cancers; 36 of these originally received neoadjuvant treatment which in retrospect might have been omitted if the STO had been applied. Main interpretation pitfalls were related to anatomical variations, borderline cases near the STO and angulation of axial imaging planes.CONCLUSIONS: Good agreement was reached for experienced radiologists. Despite considerable variation among less-expert readers, use of the STO could have changed treatment in ±1/4 of patients in our cohort. Identified interpretation pitfalls may serve as a basis for teaching and to further optimize MR protocols.

Purpose To analyze how the MRI reporting of rectal cancer has evolved (following guideline updates) in The Netherlands. Methods Retrospective analysis of 712 patients (2011–2018) from 8 teaching hospitals in The Netherlands with available original radiological staging reports that were re-evaluated by a dedicated MR expert using updated guideline criteria. Original reports were classified as “free-text,” “semi-structured,” or “template” and completeness of reporting was documented. Patients were categorized as low versus high risk, first based on the original reports (high risk = cT3-4, cN+, and/or cMRF+) and then based on the expert re-evaluations (high risk = cT3cd-4, cN+, MRF+, and/or EMVI+). Evolutions over time were studied by splitting the inclusion period in 3 equal time periods. Results A significant increase in template reporting was observed (from 1.6 to 17.6–29.6%; p Conclusion Updated concepts of risk stratification have increasingly been adopted, accompanied by an increase in template reporting and improved completeness of reporting. Use of updated guideline criteria resulted in considerable downstaging (of mainly high-risk cT-stage and nodal stage). Graphic abstract

A woman had abdominal pain due to ischaemia of the small intestine. This was probably caused by torsion due to pandiverticulosis.

The problem of what factors are present in variables which have been used in the past to measure some phase of motor co-ordination was investigated further. Ninety-two third and fourth grade girls were used in this study. The multiple-group method of factoring was used to extract nine factors. Names were given to four of the factors: balancing objects, speed of change of direction of arms and hands, total body quick change of direction, and body balance. A fifth factor was tentatively identified as a vertical total body quick change of direction. Two of the factors (balancing objects and speed of change of direction of arms and hands) are similar to factors identified in a former study in which college women were used for the sample. Similarities and differences between the two studies were discussed. This comparison suggested that a different definition of motor co-ordination for different age levels should be considered.

Courses in Computer Science have undergone significant improvement during the last few years. This improvement has resulted from the introduction of guiding principles such as structured programming and top-down design. Unfortunately, even with the use of these principles, buggy programs are commonplace. More guiding principles are needed. This paper introduces the concept of generalized programs and described how they may be used as a guide in the creation of correct computer programs. The method is discussed as it relates to a first course in Computer Science, but the idea could be applicable elsewhere in the curriculum. Basically, the idea is to partition the problems usually solved in the first course into groups such that the programs for solving the problems in each group will have common features. It was not found possible to find such a group for every problem, but a majority of the problems in the first course could be grouped in this manner. For each group a generalized program is written which captures the common features of the group. When given a problem to solve, if the student can ascertain the group to which it belongs, then the generalized program for this group will give guidance for programming the solution.