Risk Factors for Abscess Development Following Percutaneous Microwave Ablation Therapy of Hepatic Tumors.

PURPOSE: To investigate risk factors associated with post-microwave ablation (MWA) abscess development. MATERIALS AND METHODS: A retrospective case-control analysis was conducted to identify hepatic MWA performed at a single tertiary medical center between January 2010 and January 2022. Case and control patients were defined as those who did or did not develop intrahepatic abscess within 3 months following MWA, respectively. Correlations between risk factors and post-MWA abscess development were assessed by Fisher's exact test. RESULTS: Between 2010 and 2022, 253 patients underwent 376 MWA sessions with post-ablation abscess complication rate of 1.1% (4/376). Complications associated with intrahepatic abscess included bacteremia, empyema, pleural abscess, subcutaneous abscess, cholangitis, bile leak, biliocutaneous and arterio-biliary fistulae, and pseudoaneurysm. One patient expired from septic shock 5 days post-ablation. All abscesses were treated by percutaneous drainage and antibiotics. One patient required concomitant placement of a biliary stent and embolization of a biliocutaneous tract. History of Sphincter of Oddi manipulation (p < 0.01), cholangiocarcinoma (p < 0.05), transarterial radioembolization (TARE) to the index lesion (p < 0.05), and abnormal serum alkaline phosphatase levels (p < 0.05) were significantly correlated with post-MWA abscess. The risk of developing post-MWA abscesses for patients with a history of cholangiocarcinoma or a history of Sphincter of Oddi manipulation were 20.0% and 27.2%, respectively. CONCLUSION: Patients with prior Sphincter of Oddi manipulation, cholangiocarcinoma, or TARE are at greater risk of developing post-MWA abscess.

Growth of the harmful benthic cyanobacterium Microseira wollei is driven by legacy sedimentary phosphorous.

Models for cyanobacterial harmful algae blooms (cHABs) in fresh waters are usually predicated on the relationship between cyanobacterial ecology and dissolved nutrients, particularly phosphorous. Here we show legacy sediment-associated phosphorous as the primary driver of a benthic cHAB, not phosphorous in the water column. Biogeographical surveys by teams of citizen science volunteers working with the University of South Carolina identified over 200 distinct mats of Microseira wollei in Lake Wateree, SC based on toxin characterization. In sum these were estimated to affect approximately 175 km of the lake's shoreline. This growth occurred under water quality conditions that were near or below the regulatory total maximum daily load for phosphorous and nitrogen. A series of established predictive models for cyanobacterial biomass growth were applied retroactively to match the measured growth with measured water quality parameters. The only component of the system that successfully predicted microbial biomass was sedimentary phosphorous. Concentrations of the Lyngbya wollei toxins (LWTs) 1, 4, 5, and 6 were determined at multiple sites over an 18-month period and a toxin inventory for the lake was calculated. Toxin profiles between sites differed at the 95% level of confidence, establishing each site as a unique mat. An empirical model of toxin production potential based on sedimentary phosphorous was developed.

Radiation Dose during Transarterial Radioembolization: A Dosimetric Comparison of Cone-Beam CT and Angio-CT Technologies.

PURPOSE: To evaluate the radiation dose differences for intraprocedural computed tomography (CT) imaging between cone-beam CT and angio-CT acquired during transarterial radioembolization (TARE) therapies for hepatocellular carcinoma. MATERIALS AND METHODS: A retrospective cohort of 22 patients who underwent 23 TARE procedures were selected. Patients were imaged in both cone-beam CT and angio-CT rooms as a part of their conventional treatment plan. Effective dose contributions from individual CT acquisitions as well as the cumulative dose contributions from procedural 3D imaging were evaluated. Angiography dose contributions were omitted. Cone-beam CT images were acquired on a C-arm Philips Allura system. Effective doses were evaluated by coupling previously published conversion factors (effective dose per dose-area product) to patient's dose-area product meter readings after the procedure. Angio-CT images were acquired on a hybrid Canon Infinix-i Aquilion PRIME system. Effective doses from angio-CT scans were estimated using Radimetrics. Comparisons of a single patient's dose differential between the 2 technologies were made. RESULTS: The mean effective dose from a single CT scan was 6.42 mSv and 5.99 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .3224), despite the greater field of view and average craniocaudal scan coverage in angio-CT. The mean effective dose summed across all CTs in a procedure was 12.89 mSv and 34.35 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .0018). CONCLUSIONS: The mean effective dose per CT scan is comparable between cone-beam CT and angio-CT when considered in direct comparison for a single patient.