Accurate Total-Body Ki Parametric Imaging with Shortened Dynamic 18F-FDG PET Scan Durations via Effective Data Processing

Background: Total-body dynamic PET (dPET) imaging using 18F-fluorodeoxyglucose (18F-FDG) has received widespread attention in clinical oncology. However, the conventionally required scan duration of approximately one hour seriously limits the application and promotion of this imaging technique. In this study, using Patlak analysis-based Ki parametric imaging as the evaluation standard, we investigated the possibility and feasibility of shortening the total-body dynamic scan duration to 30 mins post-injection (PI) with the help of a novel Patlak data processing algorithm.Methods: Total-body dPET images acquired by uEXPLORER (United Imaging Healthcare Inc.) using 18F-FDG of 15 patients with different types of tumors were analyzed in this study. Dynamic images were reconstructed into 25 frames with a specific temporal dividing protocol for the scan data acquired one hour PI. Patlak analysis-based Ki parametric imaging was carried out based on the imaging data corresponding to the first 30 mins PI, during which a Patlak data processing method based on third-order Hermite interpolation (THI) was applied. The resulting Ki images and standard Ki images were compared in terms of visual imaging effect and Ki estimation accuracy to evaluate the performance of the proposed data processing algorithm for parametric imaging with dPET with a shortened scan duration.Results: With the help of Patlak data processing, acceptable Ki parametric images were obtained from dPET data acquired with a shortened scan duration. Compared to Ki images obtained from unprocessed Patlak data, the resulting images from the proposed method contained less image noise, leading to remarkably improved imaging quality. Moreover, box plot analysis showed that that 30-min Ki images obtained from processed Patlak data have higher accuracy regarding tumor lesion Ki values.Conclusion: Acceptable Ki parametric images can be acquired from dynamic imaging data corresponding to the first 30 mins PI. Patlak data processing can help achieve higher Ki imaging quality and higher accuracy regarding tumor lesion Ki values. Clinically, it is possible to shorten the dynamic scan duration of 18F-FDG PET to 30 mins to facilitate the usage of such imaging techniques on uEXPLORER scanners.

Using angiographic parametric imaging-derived radiomics features to predict complications and embolization outcomes of intracranial aneurysms treated by pipeline embolization devices

BackgroundPipeline embolization devices (PEDs) have gained widespread popularity in the treatment of intracranial aneurysms (IAs). However, precise predictors of treatment outcomes are still lacking. This study aimed to use angiographic parametric imaging (API)-derived radiomics features to explore whether biomarkers extracted from immediate postprocedural digital subtraction angiography (DSA) were associated with complications and embolization outcomes of IAs treated with PED without adjunctive coils.MethodsRadiomic features were extracted from postprocedural DSA by API, and radiomics feature selection and radiomics score calculation were performed by the least absolute shrinkage and selection operator (LASSO) logistic regression. Angiographic findings and clinical characteristics were screened using stepwise multivariable logistic regression analysis to identify significant variables for predicting the complication endpoint. Radiomics feature selection and radiomics risk score (RadRS) calculations were performed by LASSO Cox regression. Univariate and multivariate Cox regression analyses were used to identify significant predictors for the occlusion endpoint.ResultsWe screened 281 observations for complications and 235 observations for embolization outcomes from IAs treated in our center using PED between June 2015 and July 2020. Multivariate regression analysis showed association of the radiomics score (p<0.01) and hypertension (p=0.04) with complications. RadRS (p<0.01), symptoms (p<0.01), and age (p=0.03) were predictors of embolization outcomes. Kaplan-Meier analysis revealed that symptomatic patients (p<0.01) and those with off-label IAs (p=0.03) had shorter intervals to complete occlusion.ConclusionsBiomarkers extracted from immediate postprocedural DSA by API could be potential indicators for assessing treatment outcomes of IAs treated by PED without adjunctive coils.