No abstract

OBJECTIVEThe effect of CSF on blood coagulation is not known. Enhanced coagulation by CSF may be an issue in thrombotic complications of ventriculoatrial and ventriculosinus shunts. This study aimed to assess the effect of CSF on coagulation and its potential effect on thrombotic events affecting ventriculovenous shunts.METHODSTwo complementary experiments were performed. In a static experiment, the effect on coagulation of different CSF mixtures was evaluated using a viscoelastic coagulation monitor. A dynamic experiment confirmed the amount of clot formation on the shunt surface in a roller pump model.RESULTSCSF concentrations of 9% and higher significantly decreased the activated clotting time (ACT; 164.9 seconds at 0% CSF, 155.6 seconds at 9% CSF, and 145.1 seconds at 32% CSF). Increased clot rates (CRs) were observed starting at a concentration of 5% (29.3 U/min at 0% CSF, 31.6 U/min at 5% CSF, and 35.3 U/min at 32% CSF). The roller pump model showed a significantly greater percentage of shunt surface covered with deposits when the shunts were infused with CSF rather than Ringer’s lactate solution (90% vs 63%). The amount of clot formation at the side facing the blood flow (impact side) tended to be lower than that at the side facing away from the blood flow (wake side; 71% vs 86%).CONCLUSIONSAddition of CSF to blood accelerates coagulation. The CSF-blood–foreign material interaction promotes clot formation, which might result in thrombotic shunt complications. Further development of the ventriculovenous shunt technique should focus on preventing CSF-blood–foreign material interaction and stagnation of CSF in wake zones.

Bone imaging has been intimately associated with the diagnosis and staging of multiple myeloma (MM) for more than 5 decades, as the presence of bone lesions indicates advanced disease and dictates treatment initiation. The methods used have been evolving, and the historical radiographic skeletal survey has been replaced by whole body CT, whole body MRI (WB-MRI) and [18F]FDG-PET/CT for the detection of bone marrow lesions and less frequent extramedullary plasmacytomas.Beyond diagnosis, imaging methods are expected to provide the clinician with evaluation of the response to treatment. Imaging techniques are consistently challenged as treatments become more and more efficient, inducing profound response, with more subtle residual disease. WB-MRI and FDG-PET/CT are the methods of choice to address these challenges, being able to assess disease progression or response and to detect “minimal” residual disease, providing key prognostic information and guiding necessary change of treatment.This paper provides an up-to-date overview of the WB-MRI and PET/CT techniques, their observations in responsive and progressive disease and their role and limitations in capturing minimal residual disease. It reviews trials assessing these techniques for response evaluation, points out the limited comparisons between both methods and highlights their complementarity with most recent molecular methods (next-generation flow cytometry, next-generation sequencing) to detect minimal residual disease. It underlines the important role of PET/MRI technology as a research tool to compare the effectiveness and complementarity of both methods to address the key clinical questions.

No abstract

Objective To identify which dynamic contrast-enhanced (DCE-)MRI features best predict histological response to neoadjuvant chemotherapy in patients with an osteosarcoma. Methods Patients with osteosarcoma who underwent DCE-MRI before and after neoadjuvant chemotherapy prior to resection were retrospectively included at two different centers. Data from the center with the larger cohort (training cohort) was used to identify which method for region-of-interest selection (whole slab or focal area method) and which change in DCE-MRI features (time to enhancement, wash-in rate, maximum relative enhancement and area under the curve) gave the most accurate prediction of histological response. Models were created using logistic regression and cross-validated. The most accurate model was then externally validated using data from the other center (test cohort). Results Fifty-five (27 poor response) and 30 (19 poor response) patients were included in training and test cohorts, respectively. Intraclass correlation coefficient of relative DCE-MRI features ranged 0.81–0.97 with the whole slab and 0.57–0.85 with the focal area segmentation method. Poor histological response was best predicted with the whole slab segmentation method using a single feature threshold, relative wash-in rate <2.3. Mean accuracy was 0.85 (95%CI: 0.75–0.95), and area under the receiver operating characteristic curve (AUC-index) was 0.93 (95%CI: 0.86–1.00). In external validation, accuracy and AUC-index were 0.80 and 0.80. Conclusion In this study, a relative wash-in rate of <2.3 determined with the whole slab segmentation method predicted histological response to neoadjuvant chemotherapy in osteosarcoma. Consistent performance was observed in an external test cohort.