Background Solid pseudopapillary neoplasms of the pancreas (SPPN) can relapse very late, but little is known about risk factors for recurrence and optimal treatment. We aimed to identify risk factors for recurrence and to analyze treatment modalities in all French pediatric cases of SPPN over the past 20 years. Material and methods Data were collected from pediatric oncologists and surgeons, and also from adult pancreatic surgeons in order to identify late recurrences. Results Fifty‐one patients (41 girls) were identified. Median age at diagnosis was 13.1 years [8.7–17.9]. Abdominal pain was the commonest presenting symptom (32/49, 65%). The tumor was located in the pancreatic head in 24 patients (47%). Preoperative biopsy or cytology was performed in 14 cases (28%). All patients were operated with a median of 23 days [0–163] after diagnosis. The rate of postoperative morbidity was 29%. With a median follow‐up of 65 months [0.3–221], the overall and event‐free survival was 100% and 71%, respectively. Seven patients (13.7%) relapsed with a median of 43 months [33–94] after initial surgery. Six were treated surgically, either alone (n = 3) or with perioperative chemotherapy (n = 2) or hyperthermic intraperitoneal chemotherapy (n = 1). One patient in whom further treatment was not feasible was still alive at last news. Risk factors for recurrence were positive surgical margins (P = 0.03) and age less than 13.5 years at diagnosis (P = 0.03). Conclusions SPPN recurrence in this pediatric series was a rare and late event that did not undermine overall survival. Complete surgical removal of recurrent tumors appears to be the best option.

).q RSNA, 2014 Purpose:To evaluate if measurement of split renal function (SRF) with dynamic contrast material-enhanced (DCE) magnetic resonance (MR) urography is equivalent to that with renal scintigraphy (RS) in patients suspected of having chronic urinary obstruction. Materials and Methods:The study protocol was approved by the institutional ethics committee of the coordinating center on behalf of all participating centers. Informed consent was obtained from all adult patients or both parents of children. This prospective, comparative study included 369 pediatric and adult patients from 14 university hospitals who were suspected of having chronic or intermittent urinary obstruction, and data from 295 patients with complete data were used for analysis. SRF was measured by using the area under the curve and the Patlak-Rutland methods, including successive review by a senior and an expert reviewer and measurement of intra-and interobserver agreement for each technique. An equivalence test for mean SRF was conducted with an a of 5%. Results:Reproducibility was substantial to almost perfect for both methods. Equivalence of DCE MR urography and RS for measurement of SRF was shown in patients with moderately dilated kidneys (P , .001 with the Patlak-Rutland method). However, in severely dilated kidneys, the mean SRF measurement was underestimated by 4% when DCE MR urography was used compared with that when RS was used. Age and type of MR imaging device had no significant effect. Conclusion:For moderately dilated kidneys, equivalence of DCE MR urography to RS was shown, with a standard deviation of approximately 12% between the techniques, making substitution of DCE MR urography for RS acceptable. For severely dilated kidneys, a mean underestimation of SRF of 4% should be expected with DCE MR urography, making substitution questionable.q RSNA, 2014

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International audienceIn dynamic contrast-enhanced magnetic resonance imaging, segmentation of internal kidney structures like cortex, medulla and cavities is essential for functional assessment. To avoid fastidious and time-consuming manual segmentation, semi-automatic methods have been recently developed. Some of them use the differences between temporal contrast evolution in each anatomical region to perform functional segmentation. We test two methods where pixels are classified according to their time-intensity evolution. They both require a vector quantization stage with some unsupervised learning algorithm (K-means or Growing Neural Gas with targeting). Three or more classes are thus obtained. In the first case the method is completely automatic. In the second case, a restricted intervention by an observer is required for merging. As no ground truth is available for result evaluation, a manual anatomical segmentation is considered as a reference. Some discrepancy criteria like overlap, extra pixels and similarity index are computed between this segmentation and a functional one. The same criteria are also evaluated between the reference and another manual segmentation. Results are comparable for the two types of comparisons, proving that anatomical segmentation can be performed using functional information