Publications by authors named "Harold Litt"

114 Publications

Incremental prognostic value of visually estimated coronary artery calcium in patients undergoing positron emission tomography imaging.

Open Heart 2021 May;8(1)

Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA

Objective: Visually estimated coronary artery calcium (VECAC) from chest CT or attenuation correction (AC)/CT obtained during positron emission tomography (PET)-myocardial perfusion imaging (MPI) is feasible. Our aim was to determine the prognostic value of VECAC beyond conventional risk factors and PET imaging parameters, including coronary flow reserve (CFR).

Methods: We analysed 608 patients without known coronary artery disease who underwent PET-MPI between 2012 and 2016 and had AC/CT and/or chest CT images. We used Cox regression to estimate the association of VECAC categories (≤10, 11-400, >400 Agatston units (AU)) with the primary outcome of all-cause death, acute coronary syndrome or stroke (mean follow-up 4.3±1.8 years). C-statistics assessed the relationship between PET parameters and VECAC with the primary outcome.

Results: Mean age was 58±11 years, 65% were women and 67% were black. VECAC ≤10, 11-400 and >400 AU was observed in 68%, 12% and 20% of subjects, respectively. Compared with VECAC ≤10, VECAC categories 11-400 (HR 2.25, 95% CI 1.24 to 4.08) and >400 AU (HR 3.05, 95% CI 1.87 to 4.98) were associated with the primary outcome after adjusting for traditional risk factors, MPI findings and CFR. Adding VECAC to a model that included PET-MPI, CFR and clinical risk factors improved the prognostic value for the primary outcomes (c-statistic 0.71 to 0.75 with VECAC, p=0.01).

Conclusions: VECAC is a potent predictor of events beyond traditional risk factors and PET imaging markers, including CFR. These data further support the importance for routine VECAC implementation.
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http://dx.doi.org/10.1136/openhrt-2021-001648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8108688PMC
May 2021

Radiological Society of North America Expert Consensus Document on Reporting Chest CT Findings Related to COVID-19: Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.

Radiol Cardiothorac Imaging 2020 Apr 25;2(2):e200152. Epub 2020 Mar 25.

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104 (S.S., H.L.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (F.U.K., S.A.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (S.B.); Department of Radiology, University of Chicago Medicine, Chicago, Ill (J.H.C.); Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (M.C.); Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Calif (T.S.H.); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wis (J.P.K.); Department of Radiology, University of California San Diego, San Diego, Calif (S.K.); and Department of Radiology, New York University Langone Health, New York, NY (J.P.K.).

Routine screening CT for the identification of coronavirus disease 19 (COVID-19) pneumonia is currently not recommended by most radiology societies. However, the number of CT examinations performed in persons under investigation for COVID-19 has increased. We also anticipate that some patients will have incidentally detected findings that could be attributable to COVID-19 pneumonia, requiring radiologists to decide whether or not to mention COVID-19 specifically as a differential diagnostic possibility. We aim to provide guidance to radiologists in reporting CT findings potentially attributable to COVID-19 pneumonia, including standardized language to reduce reporting variability when addressing the possibility of COVID-19. When typical or indeterminate features of COVID-19 pneumonia are present in endemic areas as an incidental finding, we recommend contacting the referring providers to discuss the likelihood of viral infection. These incidental findings do not necessarily need to be reported as COVID-19 pneumonia. In this setting, using the term viral pneumonia can be a reasonable and inclusive alternative. However, if one opts to use the term COVID-19 in the incidental setting, consider the provided standardized reporting language. In addition, practice patterns may vary, and this document is meant to serve as a guide. Consultation with clinical colleagues at each institution is suggested to establish a consensus reporting approach. The goal of this expert consensus is to help radiologists recognize findings of COVID-19 pneumonia and aid their communication with other health care providers, assisting management of patients during this pandemic. Published under a CC BY 4.0 license.
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http://dx.doi.org/10.1148/ryct.2020200152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7233447PMC
April 2020

Magnetic Resonance Imaging in Patients With Cardiac Implantable Electronic Devices With Abandoned Leads.

JAMA Cardiol 2021 May;6(5):549-556

Department of Radiology, Division of Cardiovascular Medicine, Perelman School of Medicine of the University of Pennsylvania, Philadelphia.

Importance: Magnetic resonance imaging (MRI) is the modality of choice for many conditions. Conditional devices and novel protocols for imaging patients with legacy cardiac implantable electronic devices (CIEDs) have increased access to MRI in patients with devices. However, the presence of abandoned leads remains an absolute contraindication.

Objective: To assess if the performance of an MRI in the presence of an abandoned CIED lead is safe and whether there are deleterious effects on concomitant active CIED leads.

Design, Setting, And Participants: This cohort study included consecutive CIED recipients undergoing 1.5-T MRI with at least 1 abandoned lead between January 2013 and June 2020. MRI scans were performed at the Hospital of the University of Pennsylvania. No patients were excluded.

Exposures: CIEDs were reprogrammed based on patient-specific pacing needs. Electrocardiography telemetry and pulse oximetry were monitored continuously, and live contact with the patient throughout the scan via visual and voice contact was performed if possible. After completion of the MRI, CIED evaluation was repeated and programming returned to baseline or to a clinically appropriate setting.

Main Outcomes And Measures: Variation in pre- and post-MRI capture threshold of 50% or more, ventricular sensing 40% or more, and lead impedance 30% or more, as well as clinical sequelae such as pain and sustained tachyarrhythmia were considered significant. Long-term follow-up lead-related data were analyzed if available.

Results: A total of 139 consecutive patients (110 men [79%]) with a mean (SD) age of 65.6 (13.4) years underwent 200 MRIs of various anatomic regions including the thorax. Repeat examinations were common with a maximum of 16 examinations for 1 patient. There was a total of 243 abandoned leads with a mean (SD) of 1.22 (0.45) per patient. The mean (SD) number of active leads was 2.04 (0.78) and 64 patients (46%) were pacemaker dependent. A transmit-receive radiofrequency coil was used in 41 patients (20.5%), all undergoing MRI of the brain. There were no abnormal vital signs or sustained tachyarrhythmias. No changes in battery voltage, power-on reset events, or changes of pacing rate were noted. CIED parameter changes including decreased right atrial sensing in 4 patients and decreased left ventricular R-wave amplitude in 1 patient were transiently noted. One patient with an abandoned subcutaneous array experienced sternal heating that subsided on premature cessation of the study.

Conclusions And Relevance: The risk of MRI in patients with abandoned CIED leads was low in this large observational study, including patients who underwent examination of the thorax. The growing aggregate of data questions the absolute contraindication for MRI in patients with abandoned CIED leads.
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http://dx.doi.org/10.1001/jamacardio.2020.7572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7890450PMC
May 2021

Quantification of abdominal fat from computed tomography using deep learning and its association with electronic health records in an academic biobank.

J Am Med Inform Assoc 2021 Jun;28(6):1178-1187

Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

Objective: The objective was to develop a fully automated algorithm for abdominal fat segmentation and to deploy this method at scale in an academic biobank.

Materials And Methods: We built a fully automated image curation and labeling technique using deep learning and distributive computing to identify subcutaneous and visceral abdominal fat compartments from 52,844 computed tomography scans in 13,502 patients in the Penn Medicine Biobank (PMBB). A classification network identified the inferior and superior borders of the abdomen, and a segmentation network differentiated visceral and subcutaneous fat. Following technical evaluation of our method, we conducted studies to validate known relationships with visceral and subcutaneous fat.

Results: When compared with 100 manually annotated cases, the classification network was on average within one 5-mm slice for both the superior (0.4 ± 1.1 slice) and inferior (0.4 ± 0.6 slice) borders. The segmentation network also demonstrated excellent performance with intraclass correlation coefficients of 1.00 (P < 2 × 10-16) for subcutaneous and 1.00 (P < 2 × 10-16) for visceral fat on 100 testing cases. We performed integrative analyses of abdominal fat with the phenome extracted from the electronic health record and found highly significant associations with diabetes mellitus, hypertension, and renal failure, among other phenotypes.

Conclusions: This work presents a fully automated and highly accurate method for the quantification of abdominal fat that can be applied to routine clinical imaging studies to fuel translational scientific discovery.
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http://dx.doi.org/10.1093/jamia/ocaa342DOI Listing
June 2021

Left ventricular mural thrombus appearing as a photopenic defect on myocardial viability PET imaging.

J Nucl Cardiol 2021 Jan 5. Epub 2021 Jan 5.

Division of Cardiology, Department of Medicine, Hospital of the University of Pennsylvania, 3400 Civic Center Blvd, 11-154 South Pavilion, Philadelphia, PA, 19104, USA.

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http://dx.doi.org/10.1007/s12350-020-02480-yDOI Listing
January 2021

Society of Cardiovascular Computed Tomography / North American Society of Cardiovascular Imaging - Expert Consensus Document on Coronary CT Imaging of Atherosclerotic Plaque.

J Cardiovasc Comput Tomogr 2021 Mar-Apr;15(2):93-109. Epub 2020 Nov 9.

Mount Sinai School of Medicine, New York, NY, USA.

Coronary computed tomographic angiography (CCTA) provides a wealth of clinically meaningful information beyond anatomic stenosis alone, including the presence or absence of nonobstructive atherosclerosis and high-risk plaque features as precursors for incident coronary events. There is, however, no uniform agreement on how to identify and quantify these features or their use in evidence-based clinical decision-making. This statement from the Society of Cardiovascular Computed Tomography and North American Society of Cardiovascular Imaging addresses this gap and provides a comprehensive review of the available evidence on imaging of coronary atherosclerosis. In this statement, we provide standardized definitions for high-risk plaque (HRP) features and distill the evidence on the effectiveness of risk stratification into usable practice points. This statement outlines how this information should be communicated to referring physicians and patients by identifying critical elements to include in a structured CCTA report - the presence and severity of atherosclerotic plaque (descriptive statements, CAD-RADS™ categories), the segment involvement score, HRP features (e.g., low attenuation plaque, positive remodeling), and the coronary artery calcium score (when performed). Rigorous documentation of atherosclerosis on CCTA provides a vital opportunity to make recommendations for preventive care and to initiate and guide an effective care strategy for at-risk patients.
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http://dx.doi.org/10.1016/j.jcct.2020.11.002DOI Listing
November 2020

The Role of Imaging in the Management of Suspected or Known COVID-19 Pneumonia. A Multidisciplinary Perspective.

Ann Am Thorac Soc 2020 11;17(11):1358-1365

Department of Radiology, Cardiothoracic Imaging Division.

Coronavirus disease (COVID-19) is an illness caused by a novel coronavirus that has rapidly escalated into a global pandemic leading to an urgent medical effort to better characterize this disease biologically, clinically, and by imaging. In this review, we present the current approach to imaging of COVID-19 pneumonia. We focus on the appropriate use of thoracic imaging modalities to guide clinical management. We also describe radiologic findings that are considered typical, atypical, and generally not compatible with COVID-19. Furthermore, we review imaging examples of COVID-19 imaging mimics, such as organizing pneumonia, eosinophilic pneumonia, and other viral infections.
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http://dx.doi.org/10.1513/AnnalsATS.202006-600FRDOI Listing
November 2020

WITHDRAWN: Radiology Extenders: Impact on Throughput and Accuracy for Routine Chest Radiographs.

J Am Coll Radiol 2020 Oct 13. Epub 2020 Oct 13.

Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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http://dx.doi.org/10.1016/j.jacr.2020.09.044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553053PMC
October 2020

Surveillance Imaging following Endovascular Aneurysm Repair: State of the Art.

Semin Intervent Radiol 2020 Oct 1;37(4):356-364. Epub 2020 Oct 1.

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania.

Endovascular aneurysmal repair (EVAR) has become a prominent modality for the treatment of abdominal aortic aneurysm. Surveillance imaging is important for the detection of device-related complications, which include endoleak, structural abnormalities, and infection. Currently used modalities include ultrasound, X-ray, computed tomography, magnetic resonance imaging, and angiography. Understanding the advantages and drawbacks of each modality, as well available guidelines, can guide selection of the appropriate technique for individual patients. We review complications following EVAR and advances in surveillance imaging modalities.
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http://dx.doi.org/10.1055/s-0040-1715882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7540641PMC
October 2020

The Role of Imaging in the Management of Suspected or Known COVID-19 Pneumonia: A Multidisciplinary Perspective.

Ann Am Thorac Soc 2020 Oct 6. Epub 2020 Oct 6.

University of Pennsylvania Perelman School of Medicine, 14640, Radiology, Philadelphia, Pennsylvania, United States.

COVID-19 is an illness caused by a novel coronavirus that has rapidly escalated into a global pandemic leading to an urgent medical effort to better characterize this disease biologically, clinically and by imaging. In this review, we present the current approach to imaging of COVID-19 pneumonia. We focus on the appropriate utilization of thoracic imaging modalities to guide clinical management. We will also describe radiologic findings that are considered typical, atypical and generally not compatible with of COVID-19 infection. Further, we review imaging examples of COVID-19 imaging mimics, such as organizing pneumonia, eosinophilic pneumonia and other viral infections.
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http://dx.doi.org/10.1513/AnnalsATS.202006-600CMEDOI Listing
October 2020

Risks and Options With Gadolinium-Based Contrast Agents in Patients With CKD: A Review.

Am J Kidney Dis 2021 04 27;77(4):517-528. Epub 2020 Aug 27.

Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA.

Gadolinium-based contrast agents (GBCAs) improve the diagnostic capabilities of magnetic resonance imaging. Although initially believed to be without major adverse effects, GBCA use in patients with severe chronic kidney disease (CKD) was demonstrated to cause nephrogenic systemic fibrosis (NSF). Restrictive policies of GBCA use in CKD and selective use of GBCAs that bind free gadolinium more strongly have resulted in the virtual elimination of NSF cases. Contemporary studies of the use of GBCAs with high binding affinity for free gadolinium in severe CKD demonstrate an absence of NSF. Despite these observations and the limitations of contemporary studies, physicians remain concerned about GBCA use in severe CKD. Concerns of GBCA use in severe CKD are magnified by recent observations demonstrating gadolinium deposition in brain and a possible systemic syndrome attributed to GBCAs. Radiologic advances have resulted in several new imaging modalities that can be used in the severe CKD population and that do not require GBCA administration. In this article, we critically review GBCA use in patients with severe CKD and provide recommendations regarding GBCA use in this population.
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http://dx.doi.org/10.1053/j.ajkd.2020.07.012DOI Listing
April 2021

Iron imaging in myocardial infarction reperfusion injury.

Nat Commun 2020 06 29;11(1):3273. Epub 2020 Jun 29.

Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.

Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.
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http://dx.doi.org/10.1038/s41467-020-16923-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7324567PMC
June 2020

Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA - Secondary Publication.

J Thorac Imaging 2020 Jul;35(4):219-227

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, PA.

Routine screening CT for the identification of COVID-19 pneumonia is currently not recommended by most radiology societies. However, the number of CTs performed in persons under investigation (PUI) for COVID-19 has increased. We also anticipate that some patients will have incidentally detected findings that could be attributable to COVID-19 pneumonia, requiring radiologists to decide whether or not to mention COVID-19 specifically as a differential diagnostic possibility. We aim to provide guidance to radiologists in reporting CT findings potentially attributable to COVID-19 pneumonia, including standardized language to reduce reporting variability when addressing the possibility of COVID-19. When typical or indeterminate features of COVID-19 pneumonia are present in endemic areas as an incidental finding, we recommend contacting the referring providers to discuss the likelihood of viral infection. These incidental findings do not necessarily need to be reported as COVID-19 pneumonia. In this setting, using the term "viral pneumonia" can be a reasonable and inclusive alternative. However, if one opts to use the term "COVID-19" in the incidental setting, consider the provided standardized reporting language. In addition, practice patterns may vary, and this document is meant to serve as a guide. Consultation with clinical colleagues at each institution is suggested to establish a consensus reporting approach. The goal of this expert consensus is to help radiologists recognize findings of COVID-19 pneumonia and aid their communication with other healthcare providers, assisting management of patients during this pandemic.
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http://dx.doi.org/10.1097/RTI.0000000000000524DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255403PMC
July 2020

Effect of Gold Nanoparticle Size on Their Properties as Contrast Agents for Computed Tomography.

Sci Rep 2019 10 17;9(1):14912. Epub 2019 Oct 17.

Department of Radiology, University of Pennsylvania, 3400 Spruce St, 1 Silverstein, Philadelphia, PA, 19104, USA.

Computed tomography (CT) is one of the most commonly used clinical imaging modalities. There have recently been many reports of novel contrast agents for CT imaging. In particular, the development of gold nanoparticles (AuNP) as CT contrast agents is a topic of intense interest. AuNP have favorable characteristics for this application such as high payloads of contrast generating material, strong X-ray attenuation, excellent biocompatibility, tailorable surface chemistry, and tunable sizes and shapes. However, there have been conflicting reports on the role of AuNP size on their contrast generation for CT. We therefore sought to extensively investigate the AuNP size-CT contrast relationship. In order to do this, we synthesized AuNP with sizes ranging from 4 to 152 nm and capped them with 5 kDa m-PEG. The contrast generation of AuNP of different sizes was investigated with three clinical CT, a spectral photon counting CT (SPCCT) and two micro CT systems. X-ray attenuation was quantified as attenuation rate in Hounsfield units per unit concentration (HU/mM). No statistically significant difference in CT contrast generation was found among different AuNP sizes via phantom imaging with any of the systems tested. Furthermore, in vivo imaging was performed in mice to provide insight into the effect of AuNP size on animal biodistribution at CT dose levels, which has not previously been explored. Both in vivo imaging and ex vivo analysis with inductively coupled plasma optical emission spectroscopy (ICP-OES) indicated that AuNP that are 15 nm or smaller have long blood circulation times, while larger AuNP accumulated in the liver and spleen more rapidly. Therefore, while we observed no AuNP size effect on CT contrast generation, there is a significant effect of size on AuNP diagnostic utility.
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http://dx.doi.org/10.1038/s41598-019-50332-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797746PMC
October 2019

MRI safety and devices: An update and expert consensus.

J Magn Reson Imaging 2020 03 30;51(3):657-674. Epub 2019 Sep 30.

Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA.

The use of magnetic resonance imaging (MRI) is increasing globally, and MRI safety issues regarding medical devices, which are constantly being developed or upgraded, represent an ongoing challenge for MRI personnel. To assist the MRI community, a panel of 10 radiologists with expertise in MRI safety from nine high-volume academic centers formed, with the objective of providing clarity on some of the MRI safety issues for the 10 most frequently questioned devices. Ten device categories were identified. The panel reviewed the literature, including key MRI safety issues regarding screening and adverse event reports, in addition to the manufacturer's Instructions For Use. Using a Delphi-inspired method, 36 practical recommendations were generated with 100% consensus that can aid the clinical MRI community. Level of Evidence: 5 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:657-674.
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http://dx.doi.org/10.1002/jmri.26909DOI Listing
March 2020

The Controversy of Contrast-Induced Nephropathy With Intravenous Contrast: What Is the Risk?

Am J Kidney Dis 2020 01 28;75(1):105-113. Epub 2019 Aug 28.

Division of Nephrology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA.

Contrast-induced nephropathy (CIN) has long been observed in both experimental and clinical studies. However, recent observational studies have questioned the prevalence and severity of CIN following intravenous contrast exposure. Initial studies of acute kidney injury following intravenous contrast were limited by the absence of control groups or contained control groups that did not adjust for additional acute kidney injury risk factors, including prevalent chronic kidney disease, as well as accepted prophylactic strategies. More contemporary use of propensity score-adjusted models have attempted to minimize the risk for selection bias, although bias cannot be completely eliminated without a prospective randomized trial. Based on existing data, we recommend the following CIN risk classification: patients with estimated glomerular filtration rates (eGFRs) ≥ 45mL/min/1.73m are at negligible risk for CIN, while patients with eGFRs<30mL/min/1.73m are at high risk for CIN. Patients with eGFRs between 30 and 44mL/min/1.73m are at an intermediate risk for CIN unless diabetes mellitus is present, which would further increase the risk. In all patients at any increased risk for CIN, the risk for CIN needs to be balanced by the risk of not performing an intravenous contrast-enhanced study.
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http://dx.doi.org/10.1053/j.ajkd.2019.05.022DOI Listing
January 2020

Can a Simple Flip Make a Difference in MRI Safety in Patients with Cardiac Implantable Electronic Devices?

Authors:
Harold I Litt

Radiol Cardiothorac Imaging 2019 Aug 29;1(3):e190151. Epub 2019 Aug 29.

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104.

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http://dx.doi.org/10.1148/ryct.2019190151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7978001PMC
August 2019

Dual-Energy (Spectral) Late Iodine Enhancement Cardiac CT: Does a Dual-Layer Detector Make It Work?

Authors:
Harold I Litt

Radiol Cardiothorac Imaging 2019 Apr 25;1(1):e194002. Epub 2019 Apr 25.

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104.

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http://dx.doi.org/10.1148/ryct.2019194002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7977708PMC
April 2019

Accelerated free-breathing 3D T1ρ cardiovascular magnetic resonance using multicoil compressed sensing.

J Cardiovasc Magn Reson 2019 01 10;21(1). Epub 2019 Jan 10.

Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.

Background: Endogenous contrast T1ρ cardiovascular magnetic resonance (CMR) can detect scar or infiltrative fibrosis in patients with ischemic or non-ischemic cardiomyopathy. Existing 2D T1ρ techniques have limited spatial coverage or require multiple breath-holds. The purpose of this project was to develop an accelerated, free-breathing 3D T1ρ mapping sequence with whole left ventricle coverage using a multicoil, compressed sensing (CS) reconstruction technique for rapid reconstruction of undersampled k-space data.

Methods: We developed a cardiac- and respiratory-gated, free-breathing 3D T1ρ sequence and acquired data using a variable-density k-space sampling pattern (A = 3). The effect of the transient magnetization trajectory, incomplete recovery of magnetization between T1ρ-preparations (heart rate dependence), and k-space sampling pattern on T1ρ relaxation time error and edge blurring was analyzed using Bloch simulations for normal and chronically infarcted myocardium. Sequence accuracy and repeatability was evaluated using MnCl phantoms with different T1ρ relaxation times and compared to 2D measurements. We further assessed accuracy and repeatability in healthy subjects and compared these results to 2D breath-held measurements.

Results: The error in T1ρ due to incomplete recovery of magnetization between T1ρ-preparations was T1ρ = 6.1% and T1ρ = 10.8% at 60 bpm and T1ρ = 13.2% and T1ρ = 19.6% at 90 bpm. At a heart rate of 60 bpm, error from the combined effects of readout-dependent magnetization transients, k-space undersampling and reordering was T1ρ = 12.6% and T1ρ = 5.8%. CS reconstructions had improved edge sharpness (blur metric = 0.15) compared to inverse Fourier transform reconstructions (blur metric = 0.48). There was strong agreement between the mean T1ρ estimated from the 2D and accelerated 3D data (R = 0.99; P < 0.05) acquired on the MnCl phantoms. The mean R1ρ estimated from the accelerated 3D sequence was highly correlated with MnCl concentration (R = 0.99; P < 0.05). 3D T1ρ acquisitions were successful in all human subjects. There was no significant bias between undersampled 3D T1ρ and breath-held 2D T1ρ (mean bias = 0.87) and the measurements had good repeatability (COV = 6.4% and COV = 7.1%).

Conclusions: This is the first report of an accelerated, free-breathing 3D T1ρ mapping of the left ventricle. This technique may improve non-contrast myocardial tissue characterization in patients with heart disease in a scan time appropriate for patients.
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http://dx.doi.org/10.1186/s12968-018-0507-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327532PMC
January 2019

Reduced order models for transstenotic pressure drop in the coronary arteries.

J Biomech Eng 2018 Dec 5. Epub 2018 Dec 5.

Mechanical Engineering, University of California Berkeley, CA, 94720.

The efficacy of reduced order modeling for transstenotic pressure drop in the coronary arteries is presented. Coronary artery disease is a leading cause of death worldwide and the computation of fractional flow reserve from computed tomography (FFRct) has become a standard for evaluating the functional significance of a coronary stenosis. FFRct uses 3D computational fluid dynamics to simulate coronary blood flow in order to compute transstenotic pressure drop during simulated hyperemia. In this study, we evaluate different fidelity hydrodynamic models and their ability to compute transstenotic pressure drop and FFRct in the coronary arteries. Models range from simple algebraic formulae to 1D, 2D and 3D time-dependent computational fluid dynamic simulations. Although several algebraic pressure-drop formulae have been proposed in the literature, these models were found to exhibit wide variation in predictions. Nonetheless, we demonstrate an algebraic formula that provides reliable predictions over a range of stenosis severity, morphology, location and flow rate when compared to the current standard for FFRct. The accounting of viscous dissipation, flow separation and pulsatile inertial effects were found to be the most significant contributions to accurate reduce order modeling of transstenotic coronary hemodynamics.
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http://dx.doi.org/10.1115/1.4042184DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6379830PMC
December 2018

Acute Coronary and Acute Aortic Syndromes.

Radiol Clin North Am 2019 Jan;57(1):25-44

Cardiothoracic Imaging Division, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104, USA. Electronic address:

Multidetector-row computed tomography (MDCT) can provide crucial information and rapid triage of emergency department patients with suspected acute coronary syndrome (ACS) or acute aortic syndrome (AAS). Coronary computed tomography angiography has high negative predictive value to rule out ACS, and MDCT is diagnostic for AAS and its variants. Optimization of acquisition technique and up-to-date knowledge of the pathophysiology of these conditions can improve study and interpretation quality for diagnosis of ACS or AAS.
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http://dx.doi.org/10.1016/j.rcl.2018.08.004DOI Listing
January 2019

INCA (Peru) Study: Impact of Non-Invasive Cardiac Magnetic Resonance Assessment in the Developing World.

J Am Heart Assoc 2018 09;7(17):e008981

1 Cardiac Imaging Barts Heart Centre St. Bartholomew's Hospital London London United Kingdom.

Background Advanced cardiac imaging permits optimal targeting of cardiac treatment but needs to be faster, cheaper, and easier for global delivery. We aimed to pilot rapid cardiac magnetic resonance ( CMR ) with contrast in a developing nation, embedding it within clinical care along with training and mentoring. Methods and Results A cross-sectional study of CMR delivery and clinical impact assessment performed 2016-2017 in an upper middle-income country. An International partnership (clinicians in Peru and collaborators from the United Kingdom, United States, Brazil, and Colombia) developed and tested a 15-minute CMR protocol in the United Kingdom, for cardiac volumes, function and scar, and delivered it with reporting combined with training, education and mentoring in 2 centers in the capital city, Lima, Peru, 100 patients referred by local doctors from 6 centers. Management changes related to the CMR were reviewed at 12 months. One-hundred scans were conducted in 98 patients with no complications. Final diagnoses were cardiomyopathy (hypertrophic, 26%; dilated, 22%; ischemic, 15%) and 12 other pathologies including tumors, congenital heart disease, iron overload, amyloidosis, genetic syndromes, vasculitis, thrombi, and valve disease. Scan cost was $150 USD, and the average scan duration was 18±7 minutes. Findings impacted management in 56% of patients, including previously unsuspected diagnoses in 19% and therapeutic management changes in 37%. Conclusions Advanced cardiac diagnostics, here CMR with contrast, is possible using existing infrastructure in the developing world in 18 minutes for $150, resulting in important changes in patient care.
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http://dx.doi.org/10.1161/JAHA.118.008981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201420PMC
September 2018

Single-phase coronary artery CT angiography extracted from stress dynamic myocardial CT perfusion on third-generation dual-source CT: Validation by coronary angiography.

Int J Cardiol 2018 Oct 30;269:343-349. Epub 2018 Jun 30.

Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Electronic address:

Background: CT advances allow coronary arterial tree to be entirely covered during one CTP scan. Our aim was to investigate the potential value of single-phase coronary CT angiography (SP-CCTA) extracted from stress dynamic myocardial CT perfusion (CTP) for coronary artery stenosis assessment.

Methods: Consecutive symptomatic patients were prospectively recruited and scanned with an ATP-stress dynamic myocardial CTP and routine CCTA protocol using third-generation DSCT. Noise reduction was applied to optimize image quality (IQ), the CTP phase with the best enhancement of the coronary arteries was selected as the SP-CCTA. IQ was assessed qualitatively. Using coronary angiography (CAG) as the reference standard, the diagnostic performance for stenosis detection was compared for SP-CCTA and routine CCTA.

Results: 56 patients underwent the CTP and CCTA examination, among which 39 patients underwent CAG. The qualitative IQ scores of SP-CCTA were similar to that of routine CCTA (p > 0.05). On a per-segment basis, the sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy and area under the receiver-operating-characteristic curve results of SP-CCTA and routine CCTA for diagnosis of stenosis ≥50% exhibited no significant difference (SP-CCTA: 78.1%, 94.9%, 77.4%, 95.1%, 91.6% and 0.935 vs. routine CCTA: 74.7%, 95.3%, 78.0%, 95.3%, 91.6% and 0.937; all p > 0.05). The mean effective radiation dose of CTP and routine CCTA plus CTP were 3.92 ± 1.72 mSv and 5.98 ± 2.01 mSv (p < 0.05), respectively.

Conclusions: The IQ and diagnostic value of SP-CCTA was equivalent to routine CCTA on third-generation DSCT. SP-CCTA images from CTP may potentially replace a separate routine CCTA, allowing the possibility of "one-stop" cardiac examination for high-risk CAD patients who need myocardial ischemia assessment.
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http://dx.doi.org/10.1016/j.ijcard.2018.06.112DOI Listing
October 2018

Bilateral Renal Infarctions During the Use of Sumatriptan.

Kidney Int Rep 2018 Sep 16;3(5):1233-1236. Epub 2018 May 16.

Renal Electrolyte and Hypertension Division, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.

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http://dx.doi.org/10.1016/j.ekir.2018.05.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127403PMC
September 2018

State-of-the-Art Imaging for the Evaluation of Pulmonary Embolism.

Curr Treat Options Cardiovasc Med 2018 Aug 7;20(9):71. Epub 2018 Aug 7.

Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA, 19104, USA.

Purpose Of Review: CT angiography has become the gold standard for evaluation of suspected pulmonary embolism; however, continuous evolution in radiology has led to new imaging approaches that offer improved options for detection and characterization of pulmonary embolism while exposing patients to lower contrast and radiation dose. The purpose of this review is to summarize state of the art imaging approaches for the evaluation of pulmonary embolism, focusing on technical innovations in this field.

Recent Findings: The introduction of dual-energy CT has resulted in the ability to add functional and prognostic information beyond the morphologic assessment of the pulmonary arteries and potentially offer improved image quality without additional radiation burden. New approaches and strategies in CT scanning have resulted in decreased radiation exposure as well as a significant decrease in contrast material used without decreasing the sensitivity for detection of pulmonary embolism. Continuous developments and improvements in MR angiography techniques offer a valuable and efficient option for certain patient populations without the risk of radiation exposure. Improvements in the technical success rate and reliability of this modality will mean more widespread use in the future. Moving beyond planar ventilation/perfusion (V/Q) scintigraphy, nuclear imaging offers several new approaches, including the use of single photon emission computed tomography (SPECT) and SPECT/CT resulting in superior diagnostic performance and a decrease in nondiagnostic studies, potentially surpassing the diagnostic capabilities of computed tomography pulmonary angiography. Ongoing research in the use of V/Q PET/CT demonstrates superior temporal and spatial resolution and quantitative capabilities compared to SPECT-CT; this modality will likely play an increasing role in the detection and characterization of pulmonary embolism. The field of pulmonary embolism imaging has demonstrated continuous evolution in both development of novel techniques and improvement in current technologies, resulting in better detection, decreased radiation exposure, and enhanced functional information beyond morphologic characterization of the pulmonary vasculature.
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http://dx.doi.org/10.1007/s11936-018-0671-6DOI Listing
August 2018

Cardiac CT in the Emergency Department: Contrasting Evidence from Registries and Randomized Controlled Trials.

Curr Cardiol Rep 2018 03 8;20(4):24. Epub 2018 Mar 8.

Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA, 19104, USA.

Purpose Of Review: To compare outcomes between registries and randomized controlled trials of coronary computed tomographic angiography (CCTA)-based versus standard of care approaches to the initial evaluation of patients with acute chest pain.

Recent Findings: Randomized trials have demonstrated CCTA to be a safe and efficient tool for triage of low- to intermediate-risk patients presenting to the emergency department with chest pain. Recent studies demonstrate heterogeneous result using different standard of care approaches for evaluation of hard endpoints in comparison with standard evaluation. Also, there has been continued concern for increase in subsequent testing after coronary CTA. Although CCTA improves detection of coronary artery disease, it is uncertain if it will bring improvement of long-term health outcomes at this point of time. Careful analysis of the previous results and further investigation will be required to validate evaluation of hard endpoints.
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http://dx.doi.org/10.1007/s11886-018-0965-zDOI Listing
March 2018

Impact of Coronary Computed Tomography Angiography Findings on Initiation of Cardioprotective Medications.

Circulation 2017 11;136(22):2195-2197

Department of Emergency Medicine, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA (A.M.C., J.EH.).

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http://dx.doi.org/10.1161/CIRCULATIONAHA.117.029994DOI Listing
November 2017

Age- and sex-based resource utilisation and costs in patients with acute chest pain undergoing cardiac CT angiography: pooled evidence from ROMICAT II and ACRIN-PA trials.

Eur Radiol 2018 Feb 5;28(2):851-860. Epub 2017 Sep 5.

Cardiac MR PET CT Program, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.

Objectives: To determine resource utilisation according to age and gender-specific subgroups in two large randomized diagnostic trials.

Methods: We pooled patient-specific data from ACRIN-PA 4005 and ROMICAT II that enrolled subjects with acute chest pain at 14 US sites. Subjects were randomized between a standard work-up and a pathway utilizing cardiac computed tomography angiography (CCTA) and followed for the occurrence of acute coronary syndrome (ACS) and resource utilisation during index hospitalisation and 1-month follow-up. Study endpoints included diagnostic accuracy of CCTA for the detection of ACS as well as resource utilisation.

Results: Among 1240 patients who underwent CCTA, negative predictive value of CCTA to rule out ACS remained very high (≥99.4%). The proportion of patients undergoing additional diagnostic testing and cost increased with age for both sexes (p < 0.001), and was higher in men as compared to women older than 60 years (43.1% vs. 23.4% and $4559 ± 3382 vs. $3179 ± 2562, p < 0.01; respectively). Cost to rule out ACS was higher in men (p < 0.001) and significantly higher for patients older than 60 years ($2860-5935 in men, p < 0.001).

Conclusions: CCTA strategy in patients with acute chest pain results in varying resource utilisation according to age and gender-specific subgroups, mandating improved selection for advanced imaging.

Key Points: • In this analysis, CAD and ACS increased with age and male gender. • CCTA in patients with acute chest pain results in varying resource utilisation. • Significant increase of diagnostic testing and cost with age for both sexes. • Cost to rule out ACS is higher in men and patients >60 years. • Improved selection of subjects for cardiac CTA result in more resource-driven implementation.
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http://dx.doi.org/10.1007/s00330-017-4981-yDOI Listing
February 2018

R-SCAN: Cardiac CT Angiography for Acute Chest Pain.

J Am Coll Radiol 2017 09 20;14(9):1212-1214. Epub 2017 Jul 20.

Weill-Cornell Medicine, New York, New York.

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http://dx.doi.org/10.1016/j.jacr.2017.05.009DOI Listing
September 2017

Comparison of systemic right ventricular function in transposition of the great arteries after atrial switch and congenitally corrected transposition of the great arteries.

Int J Cardiovasc Imaging 2017 Dec 1;33(12):1993-2001. Epub 2017 Jul 1.

University of Washington, P. O. Box 356422, Seattle, WA, 98195-6422, USA.

In patients with transposition of the great arteries corrected by interatrial baffle (TGA) and those with congenitally corrected transposition of the great arteries (ccTGA) the right ventricle (RV) is subjected to systemic pressure and fails prematurely. Previous studies have demonstrated RV dysfunction may be more pronounced in patients with TGA. The present study sought to compare patients with TGA and ccTGA using three-dimensional (3D) techniques to comprehensively analyze the shape, volume, global and regional function in the systemic RV. We compared RV size, shape, and regional and global function in 25 patients with TGA, 17 patients with ccTGA, and 9 normal subjects. The RVs were reconstructed from cardiac Magnetic Resonance Images for 3D analyses. Compared to normal, the RV in TGA and ccTGA was dilated, rounded, and reduced in function. Compared to each other, TGA and ccTGA patients had similar RV size and shape. Global RV function was lower in TGA than ccTGA when assessed from ejection fraction (EF) (30 ± 7 vs. 35 ± 7, p = 0.02) and from normalized tricuspid annular systolic plane excursion (TAPSE) (0.10 ± 0.04 vs. 0.18 ± 0.04, p < 0.01). Basilar RV function was poorer in the TGA patients when compared to ccTGA. The systemic RVs in both TGA and ccTGA are dilated, spherical, and poorly functioning. Compared to ccTGA, TGA RVs have reduced TAPSE and worse basilar hypokinesis.
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http://dx.doi.org/10.1007/s10554-017-1201-4DOI Listing
December 2017