A proposal for a semiquantitative scoring system for lymphedema using Non-contrast Magnetic Resonance Lymphography (NMRL): Reproducibility among readers and correlation with clinical grading

PURPOSE

To assess the ability and reproducibility of Non-contrast Magnetic Resonance Lymphography (NMRL) in detecting and quantify lymphedema, using a semiquantitative scoring system.

METHODS AND MATERIAL

This is a monocentric retrospective study of 134 consecutive patients with a clinical diagnosis of limb lymphedema who performed a Non-contrast Magnetic Resonance Lymphography (NMRL) at our Institution between November 2014 and February 2017. Lymphedema was classified based both on clinical and radiologic evaluation. An NMRL total score was obtained for each limb's segment and compared to the clinical grade, used as reference standard. NMRL intra-observer, inter-observer variability and intraclass correlation were calculated. NMRL sensitivity, specificity, and accuracy in identifying lymphedema were provided. Based on score distribution an NMRL four-stage system was developed.

RESULTS

NMRL showed 92% sensitivity, 77% specificity and 82% accuracy in identifying lymphedema. An almost perfect agreement was obtained by expert operators, while substantial agreement was obtained by non-expert operators. Substantial agreement resulted also for the inter-observer variability (Cohen's Kappa K = 0.73, CI 95% [0.69-0.78]). The intra-class correlation showed an almost perfect relationship both by expert and non-expert operators. Excellent correlation between clinical grade and NMRL score and between clinical grade and NMRL stage were found for each segment.

CONCLUSIONS

NMRL is a confident and reproducible exam with high sensitivity, good specificity and high accuracy in lymphedema detection; the semiquantitative NMRL score resulted a reliable and reproducible tool able to quantify lymphedema severity.

MONDO: a neutron tracker for particle therapy secondary emission characterisation

Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient's body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.

High dynamic range CMOS image sensors in biomedical applications

The biomedical environment is one of the most recent and interesting application fields for CMOS image sensors. Low power consumption, high sensitivity and a simple interface are the main required features; nevertheless high dynamic range can be considered one of the more interesting and less investigated aspects. High Dynamic range is one of the main research fields NeuriCam has been involved in since its incipit. This work is an excursus of NeuriCam's approaches to this topic.