First experience of efficacy and radiation exposure in 320-detector row CT fluoroscopy-guided interventions

Objective: We investigated the efficacy and exposure to radiation in 320-detector row computed tomography fluoroscopy-guided (CTF-guided) interventions. Methods: We analysed 231 320-detector row CTF-guided interventions (207 patients over 2 years and 6 months) in terms of technical success rates, clinical success rates, complications, scanner settings, overall radiation doses (dose–length product, mGy*cm), patient doses of peri-interventional CT series, and interventional CT (including CTF), as a retrospective cohort study. The relationships between patient radiation dose and interventional factors were assessed using multivariate analysis. Results: Overall technical success rate was 98.7% (228/231). The technical success rates of biopsies, drainages, and aspirations were 98.7% (154/156), 98.5% (66/67), and 100% (8/8), respectively. The clinical success rate of biopsies was 93.5% (146/156). All three major complications occurred in chest biopsies. The median total radiation dose was 522.4 (393.4–819.8) mGy*cm. Of the total radiation dose, 87% was applied during the pre- and post-interventional CT series. Post-interventional CT accounted for 24.4% of the total radiation dose. Only 11.4% of the dose was applied by CTF-guided intervention. Multilinear regression demonstrated that male sex, body mass index, drainage, intervention time, and helical scan as post-interventional CT were significantly associated with higher dose. Conclusion: The 320-detector row CTF interventions achieved a high success rate. Dose reduction in post-interventional CT provides patient dose reduction without decreasing the technical success rates. Advances in knowledge: This is the first study on the relationship between various interventional outcomes and patient exposure to radiation in 320-detector row CTF-guided interventions, suggesting a new perspective on dose reduction.

Preventing vessel perforations in endovascular thrombectomy: feasibility and safety of passing the clot with a microcatheter without microwire: the wireless microcatheter technique

BackgroundTo place a stent retriever for thrombectomy in acute ischemic stroke, the clot has to be passed first. A microwire is usually used for this maneuver. As an alternative, a wireless microcatheter can be used to pass the clot.ObjectiveTo analyze the feasibility and complication rates of passing the clot using either a microwire or a wireless microcatheter.MethodsA retrospective non-randomized analysis of 110 consecutive patients with acute ischemic stroke in the anterior circulation was performed, in whom video recordings of mechanical thrombectomies were available. In total, 203 attempts at mechanical recanalization were performed.ResultsSuccessful recanalization (TICI 2b–3) was achieved in 97.3% of patients. In 71.8% of attempts the clot was successfully passed using a wireless microcatheter only. When a microwire was used initially, clot passage was successful in 95.3% of attempts. Complication rates for angiographically detectable subarachnoid hemorrhage were 6.1% when a microwire was used to pass the clot compared with 0% when a wireless microcatheter was used (p<0.001). Complication rates for angiographically occult circumscribed subarachnoid contrast extravasation observed on post-interventional CT scans were 18.2% when a microwire was used to pass the clot and 4.5% when a wireless microcatheter was used (p<0.001).ConclusionsIn most cases of mechanical recanalization the clot can be passed with a wireless microcatheter instead of a microwire. In our study this method significantly reduced the risk for vessel perforation and subarachnoid hemorrhage. We therefore recommend the use of this technique whenever possible.

Ischemic Stroke: Histological Thrombus Composition and Pre-Interventional CT Attenuation Are Associated with Intervention Time and Rate of Secondary Embolism

Background and Purpose: The introduction of stent retrievers has made the complete extraction and histological analysis of human thrombi possible. A number of large randomized trials have proven the efficacy of thrombectomy for ischemic stroke; however, thrombus composition could have an impact on the efficacy and risk of the intervention. We therefore investigated the impact of histologic thrombus features on interventional outcome and procedure-related embolisms. For a pre-interventional estimation of histologic features and outcome parameters, we assessed the pre-interventional CT attenuation of the thrombi. Methods: We prospectively included all consecutive patients with occlusion of the middle cerebral artery who underwent thrombectomy between December 2013 and February 2016 at our university medical center. Samples were histologically analyzed (H&amp;E, Elastica van Gieson, Prussian blue); additionally, immunohistochemistry for CD3, CD20, and CD68/KiM1P was performed. Main thrombus components (fibrin, erythrocytes, and white blood cells) were determined and compared to intervention time, frequency of secondary embolisms, as well as additional clinical and interventional parameters. Additionally, we assessed the pre-interventional CT attenuation of the thrombi in relation to the unaffected side (rHU) and their association with histologic features. Results: One hundred eighty patients were included; of these, in 168 patients (93.4%), complete recanalization was achieved and 27 patients (15%) showed secondary embolism in the control angiogram. We observed a significant association of high amounts of fibrin (p < 0.001), low percentage of red blood cells (p < 0.001), and lower rHU (p < 0.001) with secondary embolism. Higher rHU values were significantly associated with higher amounts of fibrin (p ≤ 0.001) and low percentage of red blood cells (p ≤ 0.001). Additionally, high amounts of fibrin were associated with longer intervention times (p ≤ 0.001), whereas thrombi with high amounts of erythrocytes correlated with shorter intervention times (p ≤ 0.001). ROC analysis revealed reliable prediction of secondary embolisms for low rHU (AUC = 0.746; p ≤ 0.0001), low amounts of RBC (AUC = 0.764; p ≤ 0.0001), and high amounts of fibrin (AUC = 0.773; p ≤ 0.0001). Conclusions: Fibrin-rich thrombi with low erythrocyte percentage are significantly associated with longer intervention times. Embolisms in the thrombectomy process occur more often in thrombi with a small fraction of red blood cells and a low CT-density, suggesting a higher fragility of these thrombi.