Sion Roy

Dr. Sion Roy


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2020 in Journal of Electrocardiology
Verified
Journal Article
Closed access
SRSion Roy
Sion Roy
SSSonia U. Shah
Sonia U. Shah
EVEva Villa-Lopez
Eva Villa-Lopez
MMMary Murillo
Mary Murillo
NANataly Arenas
Nataly Arenas
PPPriya Pillutla
Priya Pillutla

Verified
Journal Article
Open access
PDF file
AAAyman Abdelkarim
Ayman Abdelkarim
SRSion Roy
Sion Roy
AKApril Kinninger
April Kinninger
ASAzadeh Salek
Azadeh Salek
OBOlivia Baranski
Olivia Baranski
Matthew Jay BudoffMatthew Jay Budoff
Matthew Jay Budoff
Objective: This study aims to evaluate image quality in patients with heart rates above or equal to 70 beats per minute (bpm), performed on a 16 cm scanner (256-slice General Electric Revolution) in comparison to a CT scanner with only 4 cm of coverage (64 slice Volume CT). Background: Recent advancements in image acquisition, such as whole-heart coverage in a single rotation and post-processing methods in coronary computed tomographic angiography (CCTA), include motion-correction algorithms, such as SnapShot Freeze (SSF), which improve temporal resolution and allow for the assessment of coronary artery disease (CAD) with lower motion scores and better image qualities. Studies from the comprehensive evaluation of high temporal- and spatial-resolution cardiac CT using a wide coverage system (CONVERGE) registry (a multicenter registry at four centers) have shown the 16 cm CT scanner having a better image quality in comparison to the 4 cm scanner. However, these studies failed to include patients with undesirable or high heart rates due to well-documented poor image acquisition on prior generations of CCTA scanners. Methods: A prospective, observational, multicenter cohort study comparing image quality, quantitively and qualitatively, on scans performed on a 16 cm CCTA in comparison to a cohort of images captured on a 4 cm CCTA at four centers. Participants were recruited based on broad inclusion criteria, and each patient in the 16 cm CCTA arm of the study received a CCTA scan using a 256-slice, whole-heart, single-beat scanner. These patients were then matched by age, gender, and heart rate to patients who underwent CCTA scans on a 4 cm CT scanner. Image quality was graded based on the signal-to-noise ratio, contrast-to-noise ratio, and on a Likert scale of 0–4: 0, very poor—4, excellent. Results: 104 patients were evaluated for this study. The mean heart rate was 75 ± 7 in the 4 cm scanner and 75 ± 7 in the 16 cm one (p = 0.426). The signal-to-noise and contrast-to-noise ratios were higher in the 16 cm scanner (p = 0.0001). In addition, more scans were evaluated as having an excellent quality on the 16 cm scanner than on the 4 cm scanner (p < 0.0001) based on a 4-point Likert scale. Conclusions: The 16 cm scanner has a superior image quality for fast heart rates compared to the 4 cm scanner. This study shows that there is a significantly higher frequency of excellent and good studies showing better contrast-to-noise and signal-to-noise ratios with the 16 cm scanner compared to the 4 cm scanner.

26 July 2022 in Clinical Imaging
Verified
Journal Article
Closed access
LCLavanya Cherukuri
Lavanya Cherukuri
AKApril Kinninger
April Kinninger
DBDivya Birudaraju
Divya Birudaraju
EJEranthi Jayawardena
Eranthi Jayawardena
VMVenkat Sanjay Manubolu
Venkat Sanjay Manubolu
SRSion Roy
Sion Roy

Verified
Journal Article
Open access
PDF file
Matthew Jay BudoffMatthew Jay Budoff
Matthew Jay Budoff
HLHong Seok Lee
Hong Seok Lee
SRSion Roy
Sion Roy
CSChandana Shekar
Chandana Shekar
Iodixanol is an iso-osmolar non-ionic dimeric hydrophilic contrast agent with a higher viscosity than the monomeric agents. It is the only Food and Drug Administration (FDA)-approved iso-osmolar agent in the United States, and it is the only contrast agent with an FDA-approved indication for use in cardiac computed tomographic angiography (CCTA), to assist in the diagnostic evaluation of patients with suspected coronary artery disease. In clinical studies, it has been noted to have fewer side effects and similar image quality when compared to low-osmolar contrast media. This can be attributed to the pharmacological properties of iodixanol. These contrast agents are used for coronary computed tomography angiography and cardiac catheterization. In this article, the use, tolerability, and efficacy of iodixanol are reviewed, specifically evaluating the use of CCTA and coronary angiography, including outcome studies, randomized trials, and comparisons to other contrast agents.

3 August 2023 in Journal of Computer Assisted Tomography
Verified
Journal Article
Closed access
KDKimberly Ding
Kimberly Ding
SLSuvasini Lakshmanan
Suvasini Lakshmanan
MHMateusz Holda
Mateusz Holda
AKApril Kinninger
April Kinninger
VMVenkat S. Manubolu
Venkat S. Manubolu
SRSion Roy
Sion Roy
Objective Nonalcoholic fatty liver disease not only shares multiple risk factors with cardiovascular disease but also independently predicts its increased risk and related outcomes. Here, we evaluate reproducibility of 3-dimensional (3D) liver volume segmentation method to identify fatty liver on noncontrast cardiac computed tomography (CT) and compare measures with previously validated 2-dimensional (2D) segmentation CT criteria for the measurement of liver fat. Methods The study included 68 participants enrolled in the EVAPORATE trial and underwent serial noncontrast cardiac CT. Liver attenuation < 40 Hounsfield units (HU) was used for diagnosing fatty liver, as done in the MESA study. Two-dimensional and 3D segmentation of the liver were performed by Philips software. Bland-Altman plot analysis was used to assess reproducibility. Results Interreader reproducibility of 3D liver mean HU measurements was 96% in a sample of 111 scans. Reproducibility of 2D and 3D liver mean HU measurements was 93% in a sample of 111 scans. Reproducibility of change in 2D and 3D liver mean HU was 94% in 68 scans. Kappa, a measure of agreement in which the 2D and 3D measures both identified fatty liver, was excellent at 96.4% in 111 scans. Conclusions Fatty liver can be reliably diagnosed and measured serially in a stable and reproducible way by 3D liver segmentation of noncontrast cardiac CT scans. Future studies need to explore the sensitivity and stability of measures for low liver fat content by 3D segmentation, over the current 2D methodology. This measure can serve as an imaging biomarker to understand mechanistic correlations between atherosclerosis, fatty liver, and cardiovascular disease risk.

22 September 2025 in Emergency Care and Medicine
Verified
Journal Article
Open access
PDF file
KIKyvan Irannejad
Kyvan Irannejad
LHLogan Hubbard
Logan Hubbard
ANAditya Narashim
Aditya Narashim
RMRuben Mora
Ruben Mora
BIBeshoy Iskander
Beshoy Iskander
SKSrikanth Krishnan
Srikanth Krishnan
Introduction: Chest pain is one of the most common and high-risk presentations in the emergency department (ED), necessitating timely and accurate evaluation to prevent adverse cardiovascular outcomes. Coronary Computed Tomography Angiography (CCTA) has emerged as a promising non-invasive modality with high sensitivity (90–100%) and a negative predictive value (98–100%) for ruling out significant coronary artery disease (CAD), as evidenced by trials such as ROMICAT II and ACRIN-PA. Despite its expanding role in ED triage, further evaluation of its impact on patient-centered outcomes is essential. Methods: A systematic review was conducted in accordance with PRISMA guidelines. Studies published between January 2010 and June 2025 were identified from PubMed, Embase, and the Cochrane Library. Eligible studies included randomized controlled trials and prospective cohort studies assessing CCTA in ED patients with suspected acute coronary syndrome (ACS), compared with alternative diagnostic strategies, and reporting outcomes, including diagnostic accuracy, time to diagnosis, ED discharge rates, hospital admissions, and cost-effectiveness. Results: Twenty-three studies comprising over 60,000 patients were included. CCTA in low- to intermediate-risk patients significantly reduced diagnostic time (up to 54%), increased early ED discharges, and lowered unnecessary admissions. It consistently demonstrated excellent diagnostic performance, with pooled sensitivity ≥90% and near-perfect negative predictive value. Economic evaluations showed reduced costs due to shorter ED stays and less downstream testing. Challenges included radiation exposure, contrast use, and incidental findings. Conclusions: CCTA enhances ED efficiency and safety in ACS evaluation, offering accurate CAD exclusion and resource optimization. Future studies should explore its long-term cost-effectiveness and integration into high-sensitivity troponin protocols.