CT Protocol Research Articles

Low-dose CT: A safe and effective imaging modality in post-operative pelvic & acetabular fixation

IntroductionPost-operative pelvic & acetabular fixation patients are conventionally imaged using 3-view radiographs (AP, inlet and outlet). The efficacy of such radiographs is inconsistent due to technical difficulties capturing an adequate view, often necessitating repeat radiographs and therefore increasing radiation exposure. Radiographs can be difficult to interpret, limiting the assessment of fracture reduction and fixation, especially with respect to metalwork positioning around articular surfaces. Traditionally, post-operative pelvic & acetabular fixation patients undergo repeat 3-view radiographs post-operatively, at 6 weeks, followed by at 3, 6, 12, 18 and 24 months. We propose a new pathway, in which patients have one low-dose pelvic CT immediately post-operatively, followed by one radiograph (AP pelvis) at the same time points. MethodsA new pelvic CT protocol was created to provide high quality 3D imaging whilst delivering a 5 times lower radiation dose (compared to normal pelvic CT). Data for all pelvic radiographs and CTs between January 2021 and March 2022 was exported. Using dose area product values, effective radiation dose and attributable lifetime cancer risk were calculated. ResultsThere were 42 patients included in the analysis (age range 15 to 87).The average effective dose for the 3-view pelvic X-rays was 0.6mSv (range 0.2 to 2.8mSv), and 1.1mSv (range 0.5 to 2.2mSv) for the low-dose pelvic CT. Traditional 7 × 3-view post-operative radiographs: 7 × 0.6mSv = 4.2mSv (corresponding to 1 in 11,000 cancer risk) Low dose post-operative CT and 6 × 1-view radiographs: 1.1mSv + (6 × 0.6mSv / 3) = 2.3mSv (corresponding to 1 in 20,000 cancer risk) ConclusionLow-dose CT scanning (in conjunction with 1-view radiographs) is an effective and safe imaging modality in the post-operative assessment of pelvic & acetabular fracture fixation, conferring a lower radiation burden, easier logistics, and higher quality images when compared to the traditional pathway of 3-view radiographs.

The prevalence of early contained vascular injury of spleen

Contained vascular injuries (CVI) of spleen include pseudoaneurysms (PSA) and arterio-venous fistulae (AV-fistulae), and their reported prevalence varies. Our purpose was to assess the prevalence of early splenic CVI seen on admission CT in patients with splenic trauma admitted to a single level 1 trauma center in 2013–2021, and its detection in different CT protocols. A retrospective, single-center longitudinal cohort study. Nine-year data (2013–2021) of all patients with suspected or manifest abdominal trauma were retrieved. All patients, > 15 years with an ICD code for splenic trauma (S36.0XX) were included. CT and angiographic examinations were identified. Reports and images were reviewed. Splenic CVI CT criterion was a focal collection of vascular contrast that decreases in attenuation with delayed imaging. Number of CVIs and treatment was based on medical records and/or available angioembolization data. Of 2805 patients with abdominal trauma, 313 patients (313/2805; 11.2%) fulfilled the study entry criteria. 256 patients (256/313; 81.8%) had a CT examination. Sixteen patients had splenectomy before CT, and the final study group included 240 patients (240/313; 76.7%). Median New Injury Severity Score (NISS) was 27 and 87.5% of patients had NISS > 15. Splenic CVI was found in 20 patients, which yields a prevalence of 8.3% (20/240; 95% CI 5.2–12.6%). In those cases with both late arterial and venous phase images available, CVI was seen in 14.5% of cases (18/124, 95% CI 8.6–22.0%). None of the patients with CVI died within 30 days of the injury. The prevalence of early splenic CVI in patients with a splenic trauma was 8.3–14.5% (95% CI 5.2–22.0%). Our data suggests that both arterial and venous phase are needed for CT diagnosis. The 30-day outcome in terms of mortality was good.

Automated Web-based Software for CT Quality Control Testing of Low-contrast Detectability using Model Observers.

The Channelized Hotelling observer (CHO) is well correlated with human observer performance in many CT detection/classification tasks but has not been widely adopted in routine CT quality control and performance evaluation, mainly because of the lack of an easily available, efficient, and validated software tool. We developed a highly automated solution - CT image quality evaluation and Protocol Optimization (CTPro), a web-based software platform that includes CHO and other traditional image quality assessment tools such as modulation transfer function and noise power spectrum. This tool can allow easy access to the CHO for both the research and clinical community and enable efficient, accurate image quality evaluation without the need of installing additional software. Its application was demonstrated by comparing the low-contrast detectability on a clinical photon-counting-detector (PCD)-CT with a traditional energy-integrating-detector (EID)-CT, which showed UHR-T3D had 6.2% higher d' than EID-CT with IR (p = 0.047) and 4.1% lower d' without IR (p = 0.122).

Correlation Diagnostic Contribution of SPECT/CT Imaging to 99mTc-DTPA Dynamic Scintigraphy in Patients with Different Renal Pathologies

Introduction: Dynamic renal scintigraphy with 99mTechnetium diethylenetriaminepentaacetic acid (99mTc-DTPA) is a widely performed imaging method to evaluate kidney function of patients with various renal pathologies. However the one-stop-shop combination with subsequent SPECT/CT imaging is a rarely discussed topic. Objective: The aim of the study was to evaluate the diagnostic benefits of SPECT/CT imaging to 99mTc-DTPA dynamic renal scintigraphy. Materials and Methods: A group of 32 patients (21 females and 11 males) who underwent dy- namic nephroscintigraphy with subsequent SPECT/CT was retrospectively studied. A dose of 185MBq (5mCi) 99mTc-DTPA was intravenously applied. A low-dose non-contrast CT protocol was used for attenuation correction and anatomical correlation. Results: Impaired relative renal function in various degrees of left kidney was detected in 18 patients (56%) and of right kidney in 14 patients (44%). SPECT/CT imaging identified the particular cause for the renal dysfunction in the analyzed subjects. The hybrid imaging demonstrated urolithiasis in 11 patients, postoperative ureteral strictures in 5 patients, diagnosed urological cancer in 4 patients and external compression of ureter in 2 patients as a possible obstructive cause. Congenital renal anomalies were the identified causes of impaired renal function in 10 patients – hypoplastic kidney in 4 patients, duplex kidney in 2 patients, multiple cortical cysts in 2 patients, aberrant vessel obstructing the pyeloureteral segment in 1 patient and horseshoe kidney in 1 patient. Conclusion: Dynamic renal scintigraphy combined with SPECT/CT is a very useful clinical tool, by providing not only functional but also anatomical information of the urinary tract, especially in the evaluation of obstructive uropathies and congenital renal abnormalities, that has the potential to change clinical management.

Commissioning and clinical implementation of an independent dose calculation system for scanned proton beams.

Experimental patient-specific QA (PSQA) is a time and resource-intensive process, with a poor sensitivity in detecting errors. Radiation therapy facilities aim to substitute it by means of independent dose calculation (IDC) in combination with a comprehensive beam delivery QA program. This paper reports on the commissioning of the IDC software tool myQAiON (IBA Dosimetry) for proton therapy and its clinical implementation at the MedAustron Ion Therapy Center. The IDC commissioning work included the validation of the beam model, the implementation and validation of clinical CT protocols, and the evaluation of patient treatment data. Dose difference maps, gamma index distributions, and pass rates (GPR) have been reviewed. The performance of the IDC tool has been assessed and clinical workflows, simulation settings, and GPR tolerances have been defined. Beam model validation showed agreement of ranges within±0.2mm, Bragg-Peak widths within±0.1mm, and spot sizes at various air gaps within±5% compared to physical measurements. Simulated dose in 2D reference fields deviated by-0.3%±0.5%, while 3D dose distributions differed by 1.8% on average to measurements. Validation of the CT calibration resulted in systematic differences of 2.0% between IDC and experimental data for tissue like samples. GPRs of 99.4±0.6% were found for head, head and neck, and pediatric CT protocols on a 2%/2mm gamma criterion. GPRs for the adult abdomen protocol were at 98.9% on average with 3%/3mm. Root causes of GPR outliers, for example, implants were identified and evaluated. IDC has been successfully commissioned and integrated into the MedAustron clinical workflow for protons in 2021. IDC has been stepwise and safely substituting experimental PSQA since February 2021. The initial reduction of proton experimental PSQA was about 25% and reached up to 90% after 1 year.

Applying Self-Supervised Learning to Image Quality Assessment in Chest CT Imaging.

Many new reconstruction techniques have been deployed to allow low-dose CT examinations. Such reconstruction techniques exhibit nonlinear properties, which strengthen the need for a task-based measure of image quality. The Hotelling observer (HO) is the optimal linear observer and provides a lower bound of the Bayesian ideal observer detection performance. However, its computational complexity impedes its widespread practical usage. To address this issue, we proposed a self-supervised learning (SSL)-based model observer to provide accurate estimates of HO performance in very low-dose chest CT images. Our approach involved a two-stage model combining a convolutional denoising auto-encoder (CDAE) for feature extraction and dimensionality reduction and a support vector machine for classification. To evaluate this approach, we conducted signal detection tasks employing chest CT images with different noise structures generated by computer-based simulations. We compared this approach with two supervised learning-based methods: a single-layer neural network (SLNN) and a convolutional neural network (CNN). The results showed that the CDAE-based model was able to achieve similar detection performance to the HO. In addition, it outperformed both SLNN and CNN when a reduced number of training images was considered. The proposed approach holds promise for optimizing low-dose CT protocols across scanner platforms.

Robustness of radiomic features in healthy abdominal parenchyma of patients with repeated examinations on dual-layer dual-energy CT

ObjectivesRobustness of radiomic features in physiological tissue is an important prerequisite for quantitative analysis of tumor biology and response assessment. In contrast to previous studies which focused on different tumors with mostly short scan-re-scan intervals, this study aimed to evaluate the robustness of radiomic features in cancer-free patients and over a clinically encountered inter-scan interval. Materials and methodsPatients without visible tumor burden who underwent at least two portal-venous phase dual energy CT examinations of the abdomen between May 2016 and January 2020 were included, while macroscopic tumor burden was excluded based upon follow-up imaging for all patients (≥3 months). Further, patients were excluded if no follow-up imaging was available, or if the CT protocol showed deviations between repeated examinations. Circular regions of interest were placed and proofread by two board-certified radiologists (4 years and 5 years experience) within the liver (segments 3 and 6), the psoas muscle (left and right), the pancreatic head, and the spleen to obtain radiomic features from normal-appearing organ parenchyma using PyRadiomics. Radiomic feature robustness was tested using the concordance correlation coefficient with a threshold of 0.75 considered indicative for deeming a feature robust. ResultsIn total, 160 patients with 480 repeated abdominal CT examinations (range: 2–4 per patient) were retrospectively included in this single-center, IRB-approved study. Considering all organs and feature categories, only 4.58 % (25/546) of all features were robust with the highest rate being found in the first order feature category (20.37 %, 22/108). Other feature categories (grey level co-occurrence matrix, grey level dependence matrix, grey level run length matrix, grey level size zone matrix, and neighborhood gray-tone difference matrix) yielded an overall low percentage of robust features (range: 0.00 %-1.19 %). A subgroup analysis revealed the reconstructed field of view and the X-ray tube current as determinants of feature robustness (significant differences in subgroups for all organs, p < 0.001) as well as the size of the region of interest (no significant difference for the pancreatic head with p = 0.135, significant difference with p < 0.001 for all other organs). ConclusionRadiomic feature robustness obtained from cancer-free subjects with repeated examinations using a consistent protocol and CT scanner was limited, with first order features yielding the highest proportion of robust features.

Protocol parameter extraction and centralization framework for comprehensive and in-depth CT protocol review and management.

CT protocol management is an arduous task that requires expertise from a variety of radiology professionals, including technologists, radiologists, radiology IT professionals, and medical physicists. Each CT vendor has unique, proprietary protocol file structures, some of which may vary by scanner model, making it difficult to develop a universal framework for distilling technical parameters to a human-readable file format. An ideal solution for CT protocol management is to minimize the work required for parameter extraction by introducing a data format into the workflow that is universal to all CT scanners. In this paper, we report a framework for CT protocol management that converts raw protocol files to an intermediary format before outputting them in a human-readable format for a variety of practical clinical applications, including routine protocol review, protocol version tracking, and cross-protocol comparisons. The framework was developed in Python 3. Technical parameters of interest were determined via collaborative effort between medical physicists and lead technologists. Protocol files were extracted and analyzed from a variety of scanners across our hospital-wide CT fleet, including various systems from Siemens and GE. Protocols were subcategorized based on relevant technical parameters into regular, dual-energy, and cardiac CT protocols. Backend code for technical parameter extraction from raw protocol files to a JavaScript Object Notation (JSON) format was performed on a per-system basis. Conversion from JSON to a readable output format (MS Excel) was performed identically for all scanners using the universal framework developed and presented in this work. Example results for Siemens and GE scanners are shown, including side-by-side comparisons for protocols with similar clinical indications. In conclusion, our CT protocol management framework may be deployed on any CT system to improve clinical efficiency in protocol review and upkeep.

Hybrid PET/MRI of large vessel vasculitis : Radiation dose compared to PET/CT with view on cumulative effective dose.

The diagnosis of large vessel vasculitis (LVV) is often challenging due to the various clinical appearances and the low prevalence. Hybrid imaging by positron emission tomography and computed tomography (PET/CT) is ahighly relevant imaging modality for diagnostics and disease surveillance but may be associated with asignificant amount of radiation dose especially in patients with complications. The aim of this retrospective analysis was to compare the image quality and impact of hybrid imaging methods PET/CT and PET/MRI on the potential for dose reduction. This retrospective single-center study included acohort of 32patients who were referred to PET/MRI for the evaluation of LVV, including graft infections and fever of unknown origin. This cohort was compared to asimilar cohort of 37patients who were examined with PET/CT in the same period. Mean radiation dose as well as image quality to establish adiagnosis were compared between the groups. The mean radiation dose applied in PET/MRI was significantly lower when compared to PET/CT (mean 6.6 mSV vs. 31.7 mSV; p < 0.001). This effect was based on the partially multiphasic CT protocols. At the same time, diagnostic image quality using a4-point scale showed similar results for both imaging modalities in the work-up of LVV. With PET/MRI, the radiation exposure can be significantly reduced with similar image quality and diagnostic impact. Patients with LVV have ahigher risk of receiving aclinically relevant cumulative effective dose (CED) and PET/MRI should be made available to them.

Comparison of dose length product and image quality of a biphasic whole-body polytrauma CT protocol with and without the automatic tube voltage selection.

A significant source of man-made radiation is now linked to medical devices especially X-ray imaging based ones like CT scans which expose the body to cumulative ionizing radiation and thus attendant cancer risks. The aim of this study was to determine whether using a combination of Automatic Tube Current Modulation (ATCM) and Automatic Tube Voltage Selection (ATVS) during two-phase whole-body CT (2PWBCT) examinations would reduce the radiation dose while preserving the image quality. This was a prospective, observational, single-centre study of 127 adult patients who had undergone the 2PWBCT polytraumatic protocol. All were examined on a Somatom Drive scanner (Siemens). The patients were divided into two groups: ATCM only (42 patients) and ATCM +ATVS (85 patients). Patients' arm positions during examination and the examination dose length product (DLP) values were recorded, as well the standard deviations (SD) of the density in reference areas on CT scans for the image quality assessment. The DLP values and image quality in the groups were compared using ANOVA. Mean Total DLP (in mGy*cm): ATCM only: 3337 +/-797, ATCM+ATVS: 3402 +/-830; P=0.674. No effect of arm position (P=0.586). Mean density SD values in reference areas (in HU) in ATCM only: 49 +/-45, 15 +/-6, 9 +/-2, 12 +/-4, 10 +/-3, in ATCM+ATVS: 48 +/-45, 17 +/-6, 11 +/-3, 15 +/-6, 12 +/-4. SD values was higher in ATCM+ATVS group (P<0.001). Combination of ATVS and ATCM in polytraumatic 2PWBCT leads to no significant radiation load reduction compared with ATCM only but does lead to a slight degradation of image quality. The radiation load is significantly reduced if the patient has their arms behind the head when scanning, regardless of the activation of ATVS.

Evaluación mediante TC de las complicaciones de la úlcera gastroduodenal

Gastric and duodenal ulcers (GDUs) are decreasing both in frequency and rate of mortality. However, GDUs with complications continue to have higher mortality rates and are seldom suspected in patients presenting with acute abdomen. Although upper endoscopy plays a central role in the diagnosis and treatment of GDUs, CT is crucial when serious complications appear, namely uncontrolled acute haemorrhage, perforation, organ penetration, or gastric obstruction. Radiologists have a special role to play in these situations, providing the diagnosis and extent of complications, thus contributing to decision making which can range from conservative management to endoscopic, surgical or interventional radiology procedures. The aim of our study is to describe the CT indications and protocols for patients with a suspected GDU with complications and present the main imaging findings for the different types of complications, while providing differential diagnoses.

Accuracy of linear measurements for implant planning based on low-dose cone beam CT protocols: a systematic review and meta-analysis.

The aim of this systematic review was to verify the accuracy of linear measurements performed on low-dose CBCT protocols for implant planning, in comparison with those performed on standard and high-resolution CBCT protocols. The literature search included four databases (Pubmed, Web of Science, Embase, and Scopus). Two reviewers independently screened titles/abstracts and full texts according to eligibility criteria, extracted the data, and examined the methodological quality. Risk of bias assessment was performed using the Quality Assessment Tool For In Vitro Studies. Random-effects meta-analysis was used for pooling measurement error data. The initial search yielded 4684 titles. In total, 13 studies were included in the systematic review, representing a total of 81 samples, while 9 studies were included in the meta-analysis. The risk of bias ranged from medium to low. The main results across the studies indicate a strong consistency in linear measurements performed on low-dose images in relation to the reference methods. The overall pooled planning measurement error from low-dose CBCT protocols was -0.24 mm (95% CI, -0.52 to 0.04) with a high level of heterogeneity, showing a tendency for underestimation of real values. Various studies found no significant differences in measurements across different protocols (eg, voxel sizes, mA settings, or dose levels), regions (incisor, premolar, molar) and types (height vs. width). Some studies, however, noted exceptions in measurements performed on the posterior mandible. Low-dose CBCT protocols offer adequate precision and accuracy of linear measurements for implant planning. Nevertheless, diagnostic image quality needs must be taken into consideration when choosing a low-dose CBCT protocol.

Standardization of a CT Protocol for Imaging Patients with Suspected COVID-19-A RACOON Project.

CT protocols that diagnose COVID-19 vary in regard to the associated radiation exposure and the desired image quality (IQ). This study aims to evaluate CT protocols of hospitals participating in the RACOON (Radiological Cooperative Network) project, consolidating CT protocols to provide recommendations and strategies for future pandemics. In this retrospective study, CT acquisitions of COVID-19 patients scanned between March 2020 and October 2020 (RACOON phase 1) were included, and all non-contrast protocols were evaluated. For this purpose, CT protocol parameters, IQ ratings, radiation exposure (CTDIvol), and central patient diameters were sampled. Eventually, the data from 14 sites and 534 CT acquisitions were analyzed. IQ was rated good for 81% of the evaluated examinations. Motion, beam-hardening artefacts, or image noise were reasons for a suboptimal IQ. The tube potential ranged between 80 and 140 kVp, with the majority between 100 and 120 kVp. CTDIvol was 3.7 ± 3.4 mGy. Most healthcare facilities included did not have a specific non-contrast CT protocol. Furthermore, CT protocols for chest imaging varied in their settings and radiation exposure. In future, it will be necessary to make recommendations regarding the required IQ and protocol parameters for the majority of CT scanners to enable comparable IQ as well as radiation exposure for different sites but identical diagnostic questions.

World Health Organization 2022 Classification Update: Radiologic and Pathologic Features of Papillary Renal Cell Carcinomas

Rationale and ObjectivesTo describe imaging and pathology features of newly defined pRCC based on the WHO 2022 update. Materials and MethodsThis retrospective study included 87 patients with 93 pathologically proven papillary RCCs who underwent pre-treatment renal mass protocol CT or MRI. Baseline and post-treatment follow-up imaging was evaluated by two radiologists systematically based on established lexicon. ResultsAt pathology, 63 (68%) were grade 1-2, 29 (31%) were grade 3-4, and 1 (%) was unreported. At surgical pathology, 84 (90%) were localized (≤pT2b), 5 (5%) were pT3a, and none were ≥pT3b; 4 (4%) had unknown pT stage (core biopsies). Thirty-three (35%) had necrosis and 39 (41%) had hemorrhage. None had sarcomatoid or rhabdoid differentiation. At imaging, 73 (83%) were solid and 16 (17%) were cystic. Of 16 cystic masses, 4 were Bosniak class IIF (3 were heterogeneously T1 hyperintense) and 12 were class IV. All were well-circumscribed. Ninety-two (99%) were hypovascular. Median follow-up for 74 patients was 30 months (IQR 12-56). One untreated patient had non-regional nodal metastasis at presentation, and 1 patient had metastasis to lymph nodes and bones after surgery, but the patient had unresected renal masses elsewhere without pathology. Otherwise, no recurrence or metastases were detected. ConclusionMost pRCCs present as a hypovascular, circumscribed, solid renal mass. A few pRCCs present as the newly defined Bosniak class IIF subtype. Our results can form the basis of a noninvasive, likelihood score to identify this relatively indolent pathology in the era of virtual biopsy and active surveillance.

Body CT examinations in oncologic patients: the impact of subspecialty radiology on radiation exposure in the clinical practice. A quality care study

PurposesThe primary objective of this retrospective study was to assess whether the CT dose delivered to oncologic patients was different in a subspecialty radiology department, compared to a general radiology department. The secondary explorative objective was to assess whether the objective image quality of CT examinations was different in the two settings.Materials and methodsChest and abdomen CT scans performed for oncologic indications were selected from a general radiology department and a subspecialty radiology department. By using a radiation dose management platform, we extracted and compared CT dose index (CTDIvol) and dose length product (DLP) both for each phase and for the entire CT exams. For objective image quality evaluation, we calculated the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) at the level of the liver and of the aorta. A P-value < 0.05 was considered significant.ResultsA total of 7098 CT examinations were included. CTDIvol was evaluated in 12,804 phases; DLP in 10,713 phases and in 6714 examinations. The CTDIvol and DLP overall were significantly lower in the subspecialty radiology department compared to the general radiology department CTDI median (IQR) 5.19 (3.91–7.00) and 5.51 (4.17–7.72), DLP median and IQR of 490.0 (342.4–710.6) and 503.4 (359.9–728.8), p < 0.001 and p = 0.01, respectively. The objective image quality showed no significant difference in the general and subspecialty radiology departments, with median and IQR of 4.03 (2.82–5.51) and 3.84 (3.09–4.94) for SNRLiv (p = 0.58); 4.81 (2.70–7.62) and 4.34 (3.05–6.25) for SNRAo (p = 0.30); 0.83 (0.20–1.89) and 1.00 (0.35–1.57) for CNRLiv (p = 0.99); 2.23 (0.09–3.83) and 1.01 (0.15–2.84) for CNRAo (p = 0.24) with SNRLiv (p = 0.58), SNRAo (p = 0.30), CNRLiv (p = 0.99) and CNRAo (p = 0.24).ConclusionIn a subspecialty radiology department, CT protocols are optimized compared to a general radiology department leading to lower doses to oncologic patients without significant objective image quality degradation.

Machine learning-based identification of contrast-enhancement phase of computed tomography scans.

Contrast-enhanced computed tomography scans (CECT) are routinely used in the evaluation of different clinical scenarios, including the detection and characterization of hepatocellular carcinoma (HCC). Quantitative medical image analysis has been an exponentially growing scientific field. A number of studies reported on the effects of variations in the contrast enhancement phase on the reproducibility of quantitative imaging features extracted from CT scans. The identification and labeling of phase enhancement is a time-consuming task, with a current need for an accurate automated labeling algorithm to identify the enhancement phase of CT scans. In this study, we investigated the ability of machine learning algorithms to label the phases in a dataset of 59 HCC patients scanned with a dynamic contrast-enhanced CT protocol. The ground truth labels were provided by expert radiologists. Regions of interest were defined within the aorta, the portal vein, and the liver. Mean density values were extracted from those regions of interest and used for machine learning modeling. Models were evaluated using accuracy, the area under the curve (AUC), and Matthew's correlation coefficient (MCC). We tested the algorithms on an external dataset (76 patients). Our results indicate that several supervised learning algorithms (logistic regression, random forest, etc.) performed similarly, and our developed algorithms can accurately classify the phase of contrast enhancement.

Abstract TP61: 15 Minutes Can Save Lives: An EMS Direct to CT Protocol for Stroke Patients in the Emergency Department

Purpose: To evaluate an Emergency Medical Services (EMS) Direct-to-CT Protocol developed and implemented to reduce diagnostic and treatment times in eligible adult patients presenting to the Emergency Department (ED) with an acute ischemic stroke (AIS). Methodology: A pre-and post-implementation design at a primary stroke center in a New Jersey small-scale urban city. The chart review consisted of 54 records of patients presenting to the adult ED by EMS with a stroke activation from September 2022 to November 2022 and was measured to determine the time of provider evaluation, door-to-Code Stroke time, door-to-CT (DTCT) time, and door-to-needle (DTN) time. Results: 50/101 (49.5%) pre-and 4/17 (23.5%) post-implementation charts met inclusion criteria. Statistically significant decreases occurred in the post-implementation period for door-toprovider evaluation time (median, 11.5 minutes vs 3 minutes; P = .026), door-to-Code Stroke activation time (median, 18.5 minutes vs 3.5 minutes; P = .002), and DTCT time (median, 21 minutes vs 7.5 minutes; P = &lt; .001). Although median DTN time was reduced, it was not statistically significant (median 72 minutes vs 53 minutes, P = .060). The rate of patients with a DTN time of &lt; 60 minutes was 50% higher in the post-implementation group. Implications for Practice: This project demonstrates improvement in the knowledge of the current American Heart Association and American Stroke Association recommended guidelines in stroke management and treatment. This program evaluation identifies improvements in DTCT and DTN times with the future integration of this protocol into a policy. The most cost-effective intervention for an acute ischemic stroke is early treatment with thrombolytics.

A Holistic Approach to CT Protocol and Dose Management

PurposeChallenges from administrative support, scanners’ heterogeneity, patient size variation, and protocol mapping hinder CT protocol and dose management. We present a holistic approach to overcome these challenges. MethodsA dose tracking software was selected with two key requirements: intelligent protocol mapping and customizable dose threshold settings according to the patient size. A multifaceted workflow was carefully implemented. It included patient size–dependent dose thresholds for e-mail alerts, a base protocol archive on a website with a unified format using an in-house developed reformat software upon protocol export, prompt dose alert follow-up, and well-controlled protocol changes. The thresholds were iteratively updated following protocol changes or review of dose statistics. The program outcome was evaluated using 11 protocols from January 2020 to May 2023 (N = 148,678) in comparison to ACR’s achievable dose (AD) and dose reference levels (DRLs). ResultsThe 75th percentile dose data were lower than the ACR’s DRL on average, ranging from −4.9% to −36%. The median doses were in a range of −23% to 19% on average in comparison with the ACR’s AD. The median value from pulmonary embolism scans initially showed 36% higher than the AD but was gradually reduced to nearly 3% lower than the AD. The percentage of unjustified alerted cases decreased from 80% in first half year of 2020 to 17% in the first 5 months of 2023. ConclusionsThe results showed that our holistic approach to protocol and dose management has been effective. The impact to practice has been prompt and sustainable.

Pre-TAVI imaging: an Italian survey by the CT PRotocol optimization (CT-PRO) group

PurposeThe purpose of this survey was to evaluate the current state-of-art of pre-TAVI imaging in a large radiological professional community.MethodsBetween December 2022 and January 2023 all members of the Italian Society of Medical and Interventional Radiology (SIRM) were invited by the CT PRotocol Optimization group (CT-PRO group) to complete an online 24-item questionnaire about pre-TAVI imaging.Results557 SIRM members participated in the survey. The greatest part of respondents were consultant radiologists employed in public hospitals and 84% claimed to routinely perform pre-TAVI imaging at their institutions. The most widespread acquisition protocol consisted of an ECG-gated CT angiography (CTA) scan of the aortic root and heart followed by a non-ECG-synchronized CTA of the thorax, abdomen, and pelvis. Contrast agent administration was generally tailored on the patient’s body weight with a preference for using high concentration contrast media. The reports were commonly written by radiologists with expertise in cardiovascular imaging, and included all the measurements suggested by current guidelines for adequate pre-procedural planning. About 60% of the subjects affirmed that the Heart Team is present at their institutions, however only 7% of the respondents regularly attended the multidisciplinary meetings.ConclusionsThis survey defines the current pre-TAVI imaging practice in a large radiological professional community. Interestingly, despite the majority of radiologists follow the current guidelines regarding acquisition and reporting of pre-TAVI imaging studies, there is still a noteworthy absence from multidisciplinary meetings and from the Heart Team.

Abstract A002: A phase II study of peri-operative modified FOLFIRINOX in localized pancreatic ductal adenocarcinoma (PDAC)

Abstract Introduction: Advances in adjuvant chemotherapy with 5-fluorouracil, irinotecan, and oxaliplatin (FFX) have improved survival for patients (pts) with resectable PDAC yet few are cured by the current standard of care. Neoadjuvant FFX may lead to early control of micrometastasis and enhance cure rates for this aggressive malignancy. Methods: We performed a single-arm phase-2 clinical trial for resectable PDAC evaluating 6 months of perioperative modified (m) FFX (NCT02047474). Patients underwent baseline pancreatic protocol CT and were reviewed for resectability by a multidisciplinary panel. Enrolled pts received 6 cycles of neoadjuvant mFFX followed by surgery and 6 cycles of adjuvant mFFX. The primary endpoint was a ≥ 66% 12-month progression-free survival (PFS). Additional endpoints included overall survival (OS), circulating tumor DNA (ctDNA), tumor molecular features and tumor Keratin 17 levels. Whole blood was prospectively collected and processed to stored plasma (median volume 5.4 mL, range: 2.6 – 10.2) for retrospective ctDNA analysis using a personalized, tumor-informed ctDNA assay (SignateraTM). Survival rates were estimated by Kaplan-Meier. Results: Forty-six pts enrolled with 63 months median follow up, median age of 65 [R 46–80], 36 (78%) were ECOG 0, 30 (65%) had an endobiliary stent and no pts had staging laparoscopy. All pts started mFFX, and 37 pts (80%) completed all 6 preop cycles. Thirty-three pts (72%) underwent surgery with 3 pts developing investigator-assessed progression during neoadjuvant mFFX. Six pts were unresectable intraoperatively, and 27 pts (59%) underwent resection per protocol (25 R0, 2 R1). Ten additional pts underwent surgery off protocol. The 12-month PFS was 78% (95% CI: 64.2–94.4), median PFS and OS were 36.5 months (95% CI: 16.6–74.5) and 37.2 months (95% CI 17.5–not reached), respectively. Two-year OS was 59% (95% CI: 45.8–74.7). Baseline ctDNA was detected in 16/22 (73%) pts, and after 6 cycles of mFFX ctDNA was detected in 3/17 (18%) of pts. Patients with a positive ctDNA test 4 weeks post-resection had worsened PFS (HR 34.0, 95% CI: 2.6-4758.6; P = 0.006) and OS (HR: 11.7, 95% CI: 1.5–129.9; P = 0.021) compared to ctDNA negative. Mutational signature analysis revealed predominant signatures to be COSMIC signatures SBS1 and SBS5 (age related), and SBS15 (mismatch repair deficiency associated) which was associated with improved OS. Using Keratin 17 as a biomarker of the basal molecular subtype, either in diagnostic needle aspirates or surgical specimens, we found that high K17 expression was associated with worse survival. Conclusion: The perioperative mFFX clinical trial for resectable PDAC met its primary endpoint with a promising survival rate, and R0 resection rate of 93%. These findings warrant further evaluation in a randomized clinical trial. Most pts with detectable ctDNA at baseline experience ctDNA clearance after 6 cycles of neoadjuvant mFFX. In the post-operative setting, ctDNA positivity was strongly associated with recurrence. Signature SBS15 and low K17 were associated with improved OS. Citation Format: Michael Cecchini, Ronald Salem, Marie Robert, Suzanne Czerniak, Moein Rajaei, Jeffrey Townsend, Ondrej Blaha, Daniel Zelterman, Jaykumar Thumar, Jeremy Kortmansky, Wajih Zaheer, Neal Fischbach, Justin Persico, Stacey Stein, Sajid Khan, Charles Cha, Kevin Billingsley, John Kunstman, Sumedha Chowdhury, Robert Tseng, Carlos Mauricio, Deanne Yugawa, Luisa Escobar-Hoyos, Kimberly Johung, Christina Wiess, Erik Spickard, Vasily N. Aushev, George Laliotis, Adham Jurdi, Minetta C. Liu, Jill Lacy. A phase II study of peri-operative modified FOLFIRINOX in localized pancreatic ductal adenocarcinoma (PDAC) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A002.