Concrete beams with notched ends are commonly used in construction. The strut and tie model is a familiar design method used for understanding such geometric discontinuities in concrete structures. The effects of applying carbon fibre-reinforced polymer laminates to strengthen the webs of notched-end concrete beams were studied in this work. To this end, 12 beams with two levels of shear reinforcement were cast and the effect of web strengthening the notched ends with polymers was studied. It was found that the beams with polymer strengthening showed up to 17% more load-carrying capacity than respective control beams without polymer strengthening. Furthermore, carbon fibre-reinforced polymer strengthening applied at an orientation of 45° was found to be more effective than that at 90°. Failure loads for both orientations were up to 9% higher than those of the respective control specimens. Retrofitting failed beams with polymer web strengthening resulted in the achievement of 90% of the failure load in comparison with the respective control beams.

e19562 Background: Central nervous system (CNS) relapse develops in 2-10% of patients with diffuse large B cell lymphoma (DLBCL) and has an adverse prognosis. Tools like IPI and CNS-IPI scores identify patients at high risk of systemic or CNS relapse based on the presence of established risk factors ( Schmitz et al. JCO 2016). International guidelines propose prophylactic intravenous high-dose methotrexate (HD-MTX) for patients at high risk of CNS relapse; however, limited data is backing this approach. Methods: We conducted a retrospective review of newly diagnosed DLBCL patients aged 18-75 years treated with curative intent at large academic medical centers in Riyadh, Saudi Arabia, between 2015-2018. Patients who were planned for CNS HD-MTX after cycles 2, 4, and 6 of R-CHOP and received at least one HD-MTX cycle were included. Results: We identified 35 DLBCL patients who received at least one R-CHOP cycle with one cycle of HD-MTX. The median IPI and CNS-IPI score were 3, (range = 0-4) and 3, (range = 0-5), respectively. The median number of R-CHOP cycles received was 6 (range 3-6) and HD-MTX 3 (range 1-6). The overall response rate was 91%, with 3 (9%) primary refractory patients per interim evaluation on cycle 3 of R-CHOP. Achieving complete remission after six cycles of RCHOP was noted in 80%, with four additional patients showed residual disease at the end of treatment evaluation. The entire cohort's overall survival was not reached, and five years estimated survival is 75%. With a median follow-up duration of 37.3 months, none of the patients relapsed after achieving CR at the end of treatment evaluation. The risk of systemic or CNS relapse in our cohort was 0%. In restricting the analysis to CNS-IPI of ≥ 4, a total of 13 patients with a median follow-up of 42 months were included; four patients did not achieve CR by the end of treatment, while nine patients continue to be in CR without any evidence of relapsed disease. Conclusions: High-dose methotrexate with high-intensity chemoimmunotherapy (R-CHOP) seems to be associated with an improvement in the expected rate of CNS relapse. Our data set is small, and a more extensive study evaluating HD-MTX's effectiveness in high-risk DLBCL is warranted.[Table: see text]

Background The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. Objective This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. Methods We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. Results SUVmax <4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (P=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax <4.35, versus 58.4% for SUVmax ≥4.35 (P=.13). The overall survival of patients with a baseline DC score <3.0 was 100%, with a median overall survival of 106.67 months. Conclusions We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (<4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS.

BACKGROUND The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. OBJECTIVE This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. METHODS We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. RESULTS SUVmax &lt;4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (<i>P</i>=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax &lt;4.35, versus 58.4% for SUVmax ≥4.35 (<i>P</i>=.13). The overall survival of patients with a baseline DC score &lt;3.0 was 100%, with a median overall survival of 106.67 months. CONCLUSIONS We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (&lt;4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS. CLINICALTRIAL