The Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) have gained widespread use in oncology clinical trials. RECIST 1.1 provides a standardized set of rules for response assessment in solid tumors using tumor shrinkage, based on standard imaging modalities. Standardized tumor response criteria are critically important in comparing results among clinical trials. 1) Review the steps in using the RECIST 1.1 guidelines 2) Present representative case examples Baseline study: First step is identifying target (measurable) and non-target (non-measurable) lesions. Non-nodal target lesions need to be > 10 mm in long axis in axial plane only, while lymph nodes need to >15 mm in short axis. Target lesions include up to 2 measurable lesions per organ and 5 total lesions. Intravenous contrast is mandatory. CT is preferred imaging study but MRI can be substituted. All other lesions are categorized as non-target lesions. Finally, sum of the diameters for all target lesion is recorded. Of note, bone lesions are not measurable, although an associated soft tissue mass is measurable. Sclerotic and lytic bone lesions are included as non-measurable disease. Nodes < 10 mm in short axis, pleural effusion, ascites and simple cysts are totally excluded from imaging response assessment. Follow up studies: Sum of the diameters of all unequivocal target lesions is recorded and percent change from baseline or nadir is calculated. Non-target lesion status is recorded as absent, present or unequivocal progression. New lesions are also reported. Overall response for target and nontarget lesions with or without new lesions is evaluated. RECIST 1.1 assigns four categories of response: complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). Future directions: Although increase in tumor size remains an important parameter for evaluating disease response, response may occur after an initial increase in tumor burden and regression of initial lesions may occur despite development of new lesions, especially with use of immunotherapy. This has led to new immunotherapy response criteria: Immune-related response criteria (irRC) and Immune-response RECIST (irRECIST). Image-based outcome measures are commonly used to assess treatment response in clinical trials and have played a role in the regulatory drug approval of oncologic therapies. Therefore, it is imperative that radiologists understand the application of image-based response criteria. Read More

Meeting name: SPR 2022 Annual Meeting & Postgraduate Course , 2022

Authors: Mhlanga Joyce, Siegel Marilyn

Keywords: RECIST 1.1, Oncology, Clinical Trials

The purpose of the educational exhibit is to review the CT imaging features of common congenital heart disease (CHD), using advanced CT technology, including PCD-CT with emphasis on both preoperative imaging and postoperative shunts. A variety of cases will be used to illustrate the features of the most prevalent congenital heart diseases. Read More

Meeting name: SPR 2023 Annual Meeting & Postgraduate Course , 2023

Authors: Steinberg Julie, Siegel Marilyn

Keywords: congenital heart disease, photon counting, CT

To develop diagnostic reference ranges (DRRs) for pediatric contrast-enhanced dual-energy CT (DECT) examinations as a function of patient size and radiation output of the CT scanner with comparison to conventional single energy CT (SECT). Read More

Meeting name: SPR 2020 Annual Meeting & Postgraduate Course , 2020

Authors: Siegel Marilyn, Ramirez Giraldo Juan Carlos

Keywords: Dual-Energy CT, Chest CT, Dose Reduction

Dual-energy CT (DECT) refers to the acquisition of CT datasets at two different energy spectra, which allows differentiation and classification of tissues. The purpose of this this poster is to describe post-processing algorithms and clinical applications of DECT in children on a dual-source CT system. Read More

Meeting name: SPR 2017 Annual Meeting & Categorical Course , 2017

Authors: Qi Jing, Eutsler Eric, Siegel Marilyn

Keywords: Dual energy CT, Pediatric Radiology, Clinical application

Dual energy CT with material-specific reconstructions including iodine, pulmonary blood volume, and lung vessel images can improve assessment of vascular and associated parenchymal abnormalities. An understanding of material-specific reconstruction algorithms, clinical applications and potential pitfalls can help in accurate interpretation of dual energy CT examinations. Purpose of this exhibit is to review: Basic principles of dual energy CT material-specific reconstructions ● Iodine maps ● Pulmonary blood volume (PBV) images ● Lung vessel images Specific applications and benefits of material-specific reconstructions in cardiothoracic imaging ● Pulmonary embolism: Vessel and PBV images can improve detection of embolus and infarction ● Congenital cyanotic heart disease: Material-specific reconstructions can have a role in assessing pulmonary artery flow/lung perfusion and adequacy of reconstruction surgery ● Arteriovenous malformations: Material-specific images can increase conspicuity of small malformations and can be used to evaluate the success of embolization ● Pulmonary hypertension: Material-specific images are useful to detect subtle decreases in parenchymal perfusion and pulmonary blood flow ● Airway diseases: Reconstructions can provide information on the downhill effect of bronchial obstruction. Potential pitfalls and artifacts in interpreting material specific reconstructions ● Beam-hardening artifacts ● Diaphragmatic motion ● Cardiac motion Radiation Dose: Similar or less than single-energy CT Read More

Meeting name: SPR 2024 Annual Meeting & Postgraduate Course , 2024

Authors: Haq Adeel, Siegel Marilyn, Awali Mohamed

Keywords: Dual Energy CT, Iodine mapping, Pulmonary Blood Volume

Photon-counting detector (PCD) CT utilizes a charged semiconductor element directly paired with a high-resolution detector panel. The direct conversion of detected photons into electrical signal represents the most recent generational advance in CT technology. Changes to detector technology achieved with PCDs has the potential to reduce image noise, improve spatial resolution, improve contrast resolution, and provide multispectral imaging capability. Importantly, these gains may be achieved with an overall decrease in radiation and iodinated contrast dose. This exhibit reviews the underlying technology of the PCD using clinical scans of pediatric patients performed on the first commercially available PCCT. We present examples of (1) PCD noise reduction capability; (2) improvements in spatial resolution; (3) improvements in contrast resolution; and (4) uses of multispectral capability. These are presented in comparison to the latest generation energy integrating detector (EID) CTs to highlight reductions in radiation dose and contrast media dose. Read More

Meeting name: SPR 2023 Annual Meeting & Postgraduate Course , 2023

Authors: Cao Joseph, El-ali Alexander, Siegel Marilyn

Keywords: photon counting, CT, ALARA

Dual-energy computed tomography (DECT) decomposition software has expanded the scope of CT post-processing. It is an efficient method in pediatric thoracic imaging to define both vascular and parenchymal abnormalities<i>. </i> Read More

Meeting name: SPR 2020 Annual Meeting & Postgraduate Course , 2020

Authors: Alizadeh Houman, Siegel Marilyn, Ramirez Giraldo Juan Carlos

Keywords: Dual Energy CT, chest, pediatric

Mediastinal tumors comprise a range of congenital, neoplastic and inflammatory tumors. While many benign and malignant lesions can be differentiated by CT appearance and attenuation values, many cannot be reliably separated. The purpose of this paper is to evaluate the feasibility of dual-energy computed tomography (DECT) in differentiating a spectrum of mediastinal tumors in children Read More

Meeting name: SPR 2020 Annual Meeting & Postgraduate Course , 2020

Authors: Alizadeh Houman, Siegel Marilyn, Cullinane Mike

Keywords: Dual Energy CT, Mediastinal Tumors, children

Patients undergoing lung and stem cell transplants require serial CT examinations and hence dose reduction techniques are mandatory. The newest 3^rd generation dual-source CT scanner incorporates spectral beam shaping at 100 kilovoltage (kVp) using a dedicated tin filter (100 kVp Sn), which improves dose efficiency by removing low-energy photons that contribute little to noncontrast image quality. The purpose of this study was to compare radiation exposure in non-contrast-enhanced pediatric chest CT at 100 kVp Sn imaging and at conventional low kVp imaging in the same patient cohort. Read More

Meeting name: SPR 2020 Annual Meeting & Postgraduate Course , 2020

Authors: Siegel Marilyn, Ramirez Giraldo Juan Carlos, Cullinane Mike, Bhalla Sanjeev

Keywords: Dose Reduction, ALARA, Lung and Stem Cell Transplant