In-circuit high-frequency jet ventilation to reduce organ motion in a child undergoing sarcoma ablation.

Patients with primary or metastatic solid tumours can be treated with minimally invasive image-guided procedures as an alternative to surgical resection. Reducing organ motion during these procedures is crucial so that tumours can be accurately targeted and treatment delivered within a small margin, limiting potential damage to adjacent structures. As ventilation is the main cause of motion, there has been a shift from conventional ventilation towards the use of in-circuit high-frequency jet ventilation techniques for these procedures. We present the case of a 7-year-old who required computed tomography-guided microwave ablation of a right lung metastatic nodule under general anaesthesia. The patient's lungs were ventilated with in-circuit high-frequency jet ventilation in order to provide optimum conditions for ablation. The treatment was successfully completed and she was discharged home the following day. High-frequency jet ventilation is regularly used in our institution for adult computed tomography-guided treatments and to our knowledge, this application has not been described yet in a child this young. Our experience suggests that this technique can be safely used in paediatric patients, though further investigation of the optimum parameters for in-circuit high-frequency jet ventilation in this population is warranted.

Measurement of liver and spleen interstitial volume in patients with systemic amyloid light-chain amyloidosis using equilibrium contrast CT.

OBJECTIVES: To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden. METHODS: 26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation. RESULTS: Mean ECV in the spleen and liver was significantly greater (p < 0.0005) in amyloidotic organs (SAP grade 1-3) [spleen, liver: 0.430, 0.375] compared with healthy tissues [spleen, liver: 0.304, 0.269]. ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867). CONCLUSION: In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.