28 results on '"Liu, Peter"'
Search Results
2. Diagnostic accuracy of MRI with extracellular vs. hepatobiliary contrast material for detection of residual hepatocellular carcinoma after locoregional treatment.
- Author
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Rimola J, Davenport MS, Liu PS, Brown T, Marrero JA, McKenna BJ, and Hussain HK
- Subjects
- Carcinoma, Hepatocellular surgery, Female, Gadolinium, Gadolinium DTPA, Humans, Liver diagnostic imaging, Liver surgery, Liver Neoplasms surgery, Male, Middle Aged, Reproducibility of Results, Sensitivity and Specificity, Carcinoma, Hepatocellular diagnostic imaging, Contrast Media, Image Enhancement methods, Liver Neoplasms diagnostic imaging, Magnetic Resonance Imaging methods
- Abstract
Purpose: To compare the diagnostic accuracy of extracellular gadolinium-based contrast-enhanced MRI (Gd-MRI) and gadoxetic acid-enhanced MRI (EOB-MRI) for the assessment of hepatocellular carcinoma (HCC) response to locoregional therapy (LRT) using explant correlation as the reference standard., Methods: Forty-nine subjects with cirrhosis and HCC treated with LRT who underwent liver MRI using either Gd-MRI (n = 26) or EOB-MRI (n = 23) within 90 days of liver transplantation were included. Four radiologists reviewed the MR images blinded to histology to determine the size and percentage of viable residual HCC using a per-lesion explant reference standard. Sensitivities, specificities, accuracies, and agreement with histology for the detection residual HCC were calculated., Results: Gd-MRI had greater agreement with histology (ICC: 0.98 [0.95-0.99] vs. 0.80 [0.63-0.90]) and greater sensitivity for viable HCC (76% [13/17 50-93%] vs. 58% [7/12; 28-85%]) than EOB-MRI; specificities were similar (84% [16/19; 60-97%] vs. 85% [23/27; 66-96%]). Areas under ROC curves for detecting residual viable tumor were 0.80 (0.64-0.92) for Gd-MRI and 0.72 (0.55-0.85) for EOB-MRI. Gd-MRI had greater inter-rater agreement than EOB-MRI for determining the size of residual viable HCC (ICC: 0.96 [0.92-0.98] vs. 0.85 [0.72-0.92])., Conclusion: Gd-MRI may be more accurate and precise than EOB-MRI for the assessment of viable HCC following LRT.
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- 2019
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3. Cardiovascular Magnetic Resonance in Nonischemic Myocardial Inflammation: Expert Recommendations.
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Ferreira VM, Schulz-Menger J, Holmvang G, Kramer CM, Carbone I, Sechtem U, Kindermann I, Gutberlet M, Cooper LT, Liu P, and Friedrich MG
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- Humans, Patient Selection, Cardiac Imaging Techniques, Magnetic Resonance Imaging, Myocarditis diagnostic imaging
- Abstract
This JACC Scientific Expert Panel provides consensus recommendations for an update of the cardiovascular magnetic resonance (CMR) diagnostic criteria for myocardial inflammation in patients with suspected acute or active myocardial inflammation (Lake Louise Criteria) that include options to use parametric mapping techniques. While each parameter may indicate myocardial inflammation, the authors propose that CMR provides strong evidence for myocardial inflammation, with increasing specificity, if the CMR scan demonstrates the combination of myocardial edema with other CMR markers of inflammatory myocardial injury. This is based on at least one T2-based criterion (global or regional increase of myocardial T2 relaxation time or an increased signal intensity in T2-weighted CMR images), with at least one T1-based criterion (increased myocardial T1, extracellular volume, or late gadolinium enhancement). While having both a positive T2-based marker and a T1-based marker will increase specificity for diagnosing acute myocardial inflammation, having only one (i.e., T2-based OR T1-based) marker may still support a diagnosis of acute myocardial inflammation in an appropriate clinical scenario, albeit with less specificity. The update is expected to improve the diagnostic accuracy of CMR further in detecting myocardial inflammation., (Copyright © 2018. Published by Elsevier Inc.)
- Published
- 2018
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4. Comparison of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) and cardiac magnetic resonance (CMR) in corticosteroid-naive patients with conduction system disease due to cardiac sarcoidosis.
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Ohira H, Birnie DH, Pena E, Bernick J, Mc Ardle B, Leung E, Wells GA, Yoshinaga K, Tsujino I, Sato T, Manabe O, Oyama-Manabe N, Nishimura M, Tamaki N, Dick A, Dennie C, Klein R, Renaud J, deKemp RA, Ruddy TD, Chow BJW, Davies R, Hessian R, Liu P, Beanlands RSB, and Nery PB
- Subjects
- Adrenal Cortex Hormones administration & dosage, Adult, Aged, Cardiomyopathies pathology, Female, Fluorodeoxyglucose F18, Heart Conduction System pathology, Humans, Male, Middle Aged, Radiopharmaceuticals, Sarcoidosis pathology, Cardiomyopathies diagnostic imaging, Heart Conduction System diagnostic imaging, Magnetic Resonance Imaging, Multimodal Imaging, Positron-Emission Tomography, Sarcoidosis diagnostic imaging, Tomography, X-Ray Computed
- Abstract
Purpose: Cardiac sarcoidosis (CS) is a cause of conduction system disease (CSD). (18)F-Fluorodeoxyglucose-positron emission tomography (FDG PET) and cardiac magnetic resonance (CMR) are used for detection of CS. The relative diagnostic value of these has not been well studied. The aim was to compare these imaging modalities in this population., Methods: We recruited steroid-naive patients with newly diagnosed CSD due to CS. All CS patients underwent both imaging studies within 12 weeks of each other. Patients were classified into two groups: group A with chronic mild CSD (right bundle branch block and/or axis deviation), and group B with new-onset atrioventricular block (AVB, Mobitz type II or third-degree AVB)., Results: Thirty patients were included. Positive findings on both imaging studies were seen in 72 % of patients (13/18) in group A and in 58 % of patients (7/12) in group B. The remainder (28 %) of the patients in group A were positive only on CMR. Of the patients in group B, 8 % were positive only on CMR and 33 % were positive only on FDG PET. Patients in group A were more likely to be positive only on CMR, and patients in group B were more likely to be positive only on FDG PET (p = 0.02). Patients in group B positive only on FDG PET underwent CMR earlier relative to their symptomatology than patients positive only on CMR (median 7.0, IQR 1.5 - 34.3, vs. 72.0, IQR 25.0 - 79.5 days; p = 0.03)., Conclusion: The number of positive FDG PET and CMR studies was different in patients with CSD depending on their clinical presentation. This study demonstrated that CMR can adequately detect cardiac involvement associated with chronic mild CSD. In patients presenting with new-onset AVB and a negative CMR study, FDG PET may be useful for detecting cardiac involvement due to CS.
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- 2016
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5. Liver Mass Evaluation in Patients Without Cirrhosis: A Technique-Based Method.
- Author
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Liu PS
- Subjects
- Contrast Media, Humans, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Liver Cirrhosis, Liver Neoplasms diagnostic imaging, Liver Neoplasms diagnosis, Magnetic Resonance Imaging methods, Tomography, X-Ray Computed methods
- Abstract
Liver MR imaging is the test of choice for lesion characterization in patients without a history of chronic liver disease. Multiple pulse sequences are used in combination to reach a diagnosis. The individual/incremental value of sequences encountered in modern clinical MR imaging with respect to several commonly encountered lesions in the noncirrhotic liver is reviewed., (Copyright © 2015 Elsevier Inc. All rights reserved.)
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- 2015
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6. Knee MRI: Vascular Pathology.
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Gaetke-Udager K, Fessell DP, Liu PS, Morag Y, Brigido MK, Yablon C, and Jacobson J
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- Humans, Knee Injuries pathology, Vascular Diseases pathology, Vascular System Injuries pathology, Knee blood supply, Knee Injuries diagnosis, Magnetic Resonance Imaging methods, Vascular Diseases diagnosis, Vascular System Injuries diagnosis
- Abstract
Objective: Patients who undergo knee MRI for presumed musculoskeletal disease can have unexpected vascular findings or pathology in the imaged field. Some vascular processes are limb threatening and affect treatment planning and patient outcome., Conclusion: Unexpected vascular findings on knee MRI can range from incidental to symptomatic and can include such processes as variant anatomy, aneurysm, traumatic injury, and neoplasm. The assessment for vascular pathology should be a key component of every radiologist's search pattern when evaluating knee MRI.
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- 2015
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7. Nephrogenic systemic fibrosis risk after liver magnetic resonance imaging with gadoxetate disodium in patients with moderate to severe renal impairment: results of a prospective, open-label, multicenter study.
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Lauenstein T, Ramirez-Garrido F, Kim YH, Rha SE, Ricke J, Phongkitkarun S, Boettcher J, Gupta RT, Korpraphong P, Tanomkiat W, Furtner J, Liu PS, Henry M, and Endrikat J
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Follow-Up Studies, Humans, Liver pathology, Male, Middle Aged, Prospective Studies, Risk, Severity of Illness Index, Young Adult, Contrast Media adverse effects, Gadolinium DTPA adverse effects, Kidney Diseases complications, Magnetic Resonance Imaging, Nephrogenic Fibrosing Dermopathy chemically induced, Nephrogenic Fibrosing Dermopathy complications
- Abstract
Objective: The objective of this study was to assess the risk of gadoxetate disodium in liver imaging for the development of nephrogenic systemic fibrosis (NSF) in patients with moderate to severe renal impairment., Materials and Methods: We performed a prospective, multicenter, nonrandomized, open-label phase 4 study in 35 centers from May 2009 to July 2013. The study population consisted of patients with moderate to severe renal impairment scheduled for liver imaging with gadoxetate disodium. All patients received a single intravenous bolus injection of 0.025-mmol/kg body weight of liver-specific gadoxetate disodium. The primary target variable was the number of patients who develop NSF within a 2-year follow-up period., Results: A total of 357 patients were included, with 85 patients with severe and 193 patients with moderate renal impairment, which were the clinically most relevant groups. The mean time period from diagnosis of renal disease to liver magnetic resonance imaging (MRI) was 1.53 and 5.46 years in the moderate and severe renal impairment cohort, respectively. Overall, 101 patients (28%) underwent additional contrast-enhanced MRI with other gadolinium-based MRI contrast agents within 12 months before the start of the study or in the follow-up. No patient developed symptoms conclusive of NSF within the 2-year follow-up., Conclusions: Gadoxetate disodium in patients with moderate to severe renal impairment did not raise any clinically significant safety concern. No NSF cases were observed.
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- 2015
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8. Hepatobiliary imaging.
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Liu PS and Abramson RG
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- Biliary Tract anatomy & histology, Humans, Liver anatomy & histology, Biliary Tract pathology, Liver pathology, Magnetic Resonance Imaging methods
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- 2014
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9. MR imaging in the characterization of small renal masses.
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Willatt JM, Hussain HK, Chong S, Kappil M, Azar SF, Liu PS, Ruma JA, and Elsayes KM
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Contrast Media, Diagnosis, Differential, Female, Gadolinium, Humans, Image Enhancement, Image Processing, Computer-Assisted, Male, Middle Aged, Observer Variation, Reproducibility of Results, Retrospective Studies, Sensitivity and Specificity, Young Adult, Kidney pathology, Kidney Diseases diagnosis, Magnetic Resonance Imaging
- Abstract
Objective: The aim of our study was to evaluate the effectiveness of MR imaging for the characterization of small (<2 cm) renal lesions described as indeterminate on prior US or CT., Materials and Methods: Sixty-three small renal masses in 51 patients considered indeterminate on prior ultrasound or CT scans were included in the study. A retrospective evaluation of the examinations was performed independently by two body magnetic resonance imaging (MRI) radiologists who were unaware of the final diagnosis. A 3-point confidence scale (1: benign, 2: indeterminate, and 3: malignant) was established to determine the level of suspicion for malignancy. Interobserver agreement was determined with a weighted kappa statistic. The diagnosis was verified by imaging follow-up of at least 24 months (mean 60 months) in 53 lesions and by pathology in 10 lesions., Results: MRI detected all eight malignancies in the series. There were eight malignant lesions and two benign lesions among those with pathologic follow-up. No interval growth or evidence of malignancy in the remaining 53 lesions was found for a minimum of 24 months by repeat imaging. The sensitivity, specificity, positive predictive value, and negative predictive value of MRI for differentiating benign from malignant small renal lesions were 100% (62.9-100%, 95% CI), 94.5% (84.9-98.8%, 95% CI), 72.7% (39.1-93.6%, 95% CI), and 100% (93.1-100%, 95% CI), respectively. The kappa value for interobserver agreement was 0.77 (95% CI 0.59-0.96, p-value <0.001)., Conclusion: MR imaging is an effective method for characterizing small (<2 cm) renal masses found to be indeterminate by US or CT.
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- 2014
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10. Repeatability of diagnostic features and scoring systems for hepatocellular carcinoma by using MR imaging.
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Davenport MS, Khalatbari S, Liu PS, Maturen KE, Kaza RK, Wasnik AP, Al-Hawary MM, Glazer DI, Stein EB, Patel J, Somashekar DK, Viglianti BL, and Hussain HK
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- Adult, Aged, Aged, 80 and over, Carcinoma, Hepatocellular pathology, Contrast Media, Female, Humans, Imaging, Three-Dimensional, Liver Neoplasms pathology, Male, Meglumine analogs & derivatives, Middle Aged, Organometallic Compounds, Reproducibility of Results, Retrospective Studies, Carcinoma, Hepatocellular diagnosis, Clinical Competence, Liver Neoplasms diagnosis, Magnetic Resonance Imaging methods
- Abstract
Purpose: To determine for expert and novice radiologists repeatability of major diagnostic features and scoring systems (ie, Liver Imaging Reporting and Data System [LI-RADS], Organ Procurement and Transplantation Network [OPTN], and American Association for the Study of Liver Diseases [AASLD]) for hepatocellular carcinoma (HCC) by using magnetic resonance (MR) imaging., Materials and Methods: Institutional review board approval was obtained and patient consent was waived for this HIPAA-compliant, retrospective study. The LI-RADS discussed in this article refers to version 2013.1. Ten blinded readers reviewed 100 liver MR imaging studies that demonstrated observations preliminarily assigned LI-RADS scores of LR1-LR5. Diameter and major HCC features (arterial hyperenhancement, washout appearance, pseudocapsule) were recorded for each observation. LI-RADS, OPTN, and AASLD scores were assigned. Interreader agreement was assessed by using intraclass correlation coefficients and κ statistics. Scoring rates were compared by using McNemar test., Results: Overall interreader agreement was substantial for arterial hyperenhancement (0.67 [95% confidence interval {CI}: 0.65, 0.69]), moderate for washout appearance (0.48 [95%CI: 0.46, 0.50]), moderate for pseudocapsule (0.52 [95% CI: 050, 0.54]), fair for LI-RADS (0.35 [95% CI: 0.34, 0.37]), fair for AASLD (0.39 [95% CI: 0.37, 0.42]), and moderate for OPTN (0.53 [95% CI: 0.51, 0.56]). Agreement for measured diameter was almost perfect (range, 0.95-0.97). There was substantial agreement for most scores consistent with HCC. Experts agreed significantly more than did novices and were significantly more likely than were novices to assign a diagnosis of HCC (P < .001)., Conclusion: Two of three major features for HCC (washout appearance and pseudocapsule) have only moderate interreader agreement. Experts and novices who assigned scores consistent with HCC had substantial but not perfect agreement. Expert agreement is substantial for OPTN, but moderate for LI-RADS and AASLD. Novices were less consistent and less likely to diagnose HCC than were experts., (© RSNA, 2014.)
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- 2014
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11. Response.
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Davenport MS, Liu PS, Chenevert TL, and Hussain HK
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- Female, Humans, Male, Contrast Media administration & dosage, Contrast Media adverse effects, Dyspnea chemically induced, Gadolinium DTPA administration & dosage, Gadolinium DTPA adverse effects, Liver Diseases diagnosis, Magnetic Resonance Imaging
- Published
- 2013
12. Contemporary and emerging technologies in abdominal magnetic resonance imaging.
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Liu PS and Hussain HK
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- Contrast Media, Diffusion Magnetic Resonance Imaging methods, Humans, Image Enhancement methods, Magnetic Resonance Imaging trends, Abdomen pathology, Gastrointestinal Diseases diagnosis, Magnetic Resonance Imaging methods
- Published
- 2013
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13. Comparison of acute transient dyspnea after intravenous administration of gadoxetate disodium and gadobenate dimeglumine: effect on arterial phase image quality.
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Davenport MS, Viglianti BL, Al-Hawary MM, Caoili EM, Kaza RK, Liu PS, Maturen KE, Chenevert TL, and Hussain HK
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- Adult, Aged, Aged, 80 and over, Artifacts, Chi-Square Distribution, Female, Humans, Image Interpretation, Computer-Assisted, Injections, Intravenous, Male, Middle Aged, Prospective Studies, Contrast Media administration & dosage, Contrast Media adverse effects, Dyspnea chemically induced, Gadolinium DTPA administration & dosage, Gadolinium DTPA adverse effects, Liver Diseases diagnosis, Magnetic Resonance Imaging
- Abstract
Purpose: To determine whether acute transient dyspnea and/or arterial phase image degradation occurs more or less often after intravenous administration of gadoxetate disodium than with intravenous administration of gadobenate dimeglumine., Materials and Methods: Institutional review board approval and patient consent were obtained for this prospective observational study. One hundred ninety-eight gadolinium-based contrast media administrations (99 with gadoxetate disodium [10 mL, n = 97; 8 mL, n = 1; 16 mL, n = 1] and 99 with gadobenate dimeglumine [0.1 mmol per kilogram of body weight, maximum dose, 20 mL]) for hepatobiliary indications were assessed in 192 patients. Subjective patient complaints were assessed. Objective respiratory motion degradation on T1-weighted precontrast and dynamic postcontrast (arterial, venous, or late dynamic or extracellular) magnetic resonance (MR) imaging datasets were independently assessed in a randomized, blinded fashion by five readers using a five-point scale, with mean scores of 4 or greater indicating severe motion. Comparisons between agents were made by using χ(2) or Fisher exact test, where appropriate., Results: Significantly more patient complaints of acute transient dyspnea occurred after gadoxetate disodium administration than gadobenate dimeglumine (14% [14 of 99] vs 5% [five of 99], P = .05). There were significantly more severely degraded arterial phase data sets for gadoxetate disodium than for gadobenate dimeglumine for both the general population (17% [17 of 99] vs 2% [two of 99], P = .0007) and the subpopulation with cirrhosis (19% [14 of 72] vs 3% [one of 37], P = .02). This effect did not extend to venous (1% [one of 99] vs 2% [two of 99], P > .99 [overall population]) or late dynamic or extracellular (2% [two of 99] vs 0% [zero of 99], P = .5 [overall population]) phases. No patient required treatment for self-limited dyspnea., Conclusion: Intravenous gadoxetate disodium can result in acute self-limiting dyspnea that can have a deleterious effect on arterial phase MR image quality and occurs significantly more often than with intravenous gadobenate dimeglumine.
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- 2013
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14. Rectal imaging: part 2, Perianal fistula evaluation on pelvic MRI--what the radiologist needs to know.
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O'Malley RB, Al-Hawary MM, Kaza RK, Wasnik AP, Liu PS, and Hussain HK
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- Adult, Anal Canal anatomy & histology, Anal Canal pathology, Crohn Disease complications, Female, Humans, Intestinal Mucosa pathology, Male, Rectal Fistula classification, Rectal Fistula complications, Rectal Fistula surgery, Magnetic Resonance Imaging methods, Rectal Fistula diagnosis
- Abstract
Objective: The purpose of this article is to provide an overview of pelvic MRI for the evaluation of perianal fistulas, with a description of the technique, illustration of relevant normal anatomy, and examples of various fistula types., Conclusion: MRI evaluation of perianal fistulas can be challenging, and knowledge of relevant pelvic anatomy and fistula classification remains crucial in the diagnosis. MRI is highly accurate for fistula depiction and, by providing an accurate assessment of disease status and extension, can help surgical planning to minimize recurrence and detect clinically unapparent disease.
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- 2012
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15. Gaussian process inference for estimating pharmacokinetic parameters of dynamic contrast-enhanced MR images.
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Wang S, Liu P, Turkbey B, Choyke P, Pinto P, and Summers RM
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- Computer Simulation, Contrast Media pharmacokinetics, Data Interpretation, Statistical, Humans, Male, Models, Statistical, Normal Distribution, Reproducibility of Results, Sensitivity and Specificity, Gadolinium DTPA pharmacokinetics, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging methods, Models, Biological, Prostatic Neoplasms metabolism, Prostatic Neoplasms pathology
- Abstract
In this paper, we propose a new pharmacokinetic model for parameter estimation of dynamic contrast-enhanced (DCE) MRI by using Gaussian process inference. Our model is based on the Tofts dual-compartment model for the description of tracer kinetics and the observed time series from DCE-MRI is treated as a Gaussian stochastic process. The parameter estimation is done through a maximum likelihood approach and we propose a variant of the coordinate descent method to solve this likelihood maximization problem. The new model was shown to outperform a baseline method on simulated data. Parametric maps generated on prostate DCE data with the new model also provided better enhancement of tumors, lower intensity on false positives, and better boundary delineation when compared with the baseline method. New statistical parameter maps from the process model were also found to be informative, particularly when paired with the PK parameter maps.
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- 2012
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16. Normal MRI anatomy from head to toe.
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Liu PS
- Subjects
- Contrast Media, Humans, Reference Values, Anatomy, Magnetic Resonance Imaging
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- 2011
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17. Normal and variant pelvic anatomy on MRI.
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Wasnik AP, Mazza MB, and Liu PS
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- Contrast Media, Female, Humans, Male, Pelvis abnormalities, Reference Values, Viscera abnormalities, Magnetic Resonance Imaging methods, Pelvis anatomy & histology, Viscera anatomy & histology
- Abstract
The superior tissue contrast and flexible imaging planes afforded by magnetic resonance imaging (MRI) versus competing technologies permit optimal depiction of the pelvic viscera. Targeted protocols developed for specific pelvic visceral organs highlight important anatomic features that may not be imaged by other modalities. Therefore, a solid understanding of normal and variant pelvic anatomy is crucial for appropriate interpretation of pelvic MRI studies. This article discusses the protocol strategies and relevant anatomy with commonly encountered anatomical variants in a segmented/organ-specific manner, using gender as a broad split given the substantial variance in relevant organs., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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18. Normal and variant abdominal anatomy on magnetic resonance imaging.
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Wasnik AP, Mazza MB, Lalchandani UR, and Liu PS
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- Abdomen abnormalities, Clinical Protocols, Contrast Media, Humans, Imaging, Three-Dimensional, Reference Values, Reproducibility of Results, Abdomen anatomy & histology, Magnetic Resonance Imaging methods
- Abstract
The diagnostic usefulness of abdominal magnetic resonance (MR) imaging lies in the improved contrast resolution and ability to qualify several tissue characteristics of a specific organ or lesion. Our institution uses organ-specific protocols to facilitate technical reproducibility and optimize scan duration. These protocols are discussed individually in this article when applicable, noting that many build on a basic protocol with slight variations. Because most abdominal MR imaging studies are targeted toward an organ or area of interest, this article discusses the protocol strategies and relevant anatomy in a segmented/organ-specific manner., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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19. MR imaging and CT of the biliary tract.
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Yeh BM, Liu PS, Soto JA, Corvera CA, and Hussain HK
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- Humans, Biliary Tract diagnostic imaging, Biliary Tract pathology, Biliary Tract Diseases diagnosis, Image Enhancement methods, Magnetic Resonance Imaging methods, Tomography, X-Ray Computed methods
- Abstract
Magnetic resonance (MR) imaging and computed tomography (CT) can be useful in the diagnosis of biliary disease, with both modalities allowing detailed evaluation of the biliary tract. Careful interrogation of the images is critical, regardless of modality. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section imaging. Smooth, concentric short-segment strictures favor a benign cause, whereas abrupt, eccentric long-segment strictures favor a malignancy. At MR imaging, extrabiliary entities such as crossing vessels or metallic clip artifact may mimic strictures and should not be mistaken for disease. A stone is the most common biliary filling defect and may occur in the absence of dilated ducts. Stones commonly have a lamellated, geometric shape and are found in a dependent portion of the duct. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Improved diagnosis of biliary disease can be achieved with a knowledge of the benefits and limitations of modern MR and CT cholangiographic techniques, including the use of biliary-excreted contrast material and of various postprocessing techniques. Familiarity with the radiologic appearances of the duct lumen, wall, and surrounding structures is also important for accurate image interpretation. The rapidly evolving technology for both MR imaging and CT of the biliary tract will continue to present radiologists with opportunities as well as challenges.
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- 2009
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20. Imaging of the placenta: a multimodality pictorial review.
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Elsayes KM, Trout AT, Friedkin AM, Liu PS, Bude RO, Platt JF, and Menias CO
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- Diagnosis, Differential, Female, Humans, Pregnancy, Magnetic Resonance Imaging methods, Placenta diagnostic imaging, Placenta pathology, Placenta Diseases diagnosis, Tomography, X-Ray Computed methods, Ultrasonography methods
- Abstract
The placenta is often overlooked in the routine evaluation of a normal gestation, receiving attention only when an abnormality is detected. Although uncommon, abnormalities of the placenta are important to recognize owing to the potential for maternal and fetal morbidity and mortality. Pathologic conditions of the placenta include placental causes of hemorrhage, gestational trophoblastic disease, retained products of conception, nontrophoblastic placental tumors, metastases, and cystic lesions. Sonography remains the imaging modality of choice for evaluation of the placenta. Magnetic resonance (MR) imaging can be of added diagnostic value when further characterization is required, particularly in the setting of invasive placental processes such as placenta accreta and gestational trophoblastic disease. Computed tomography (CT) has a limited role in the evaluation of placental disease owing to limited tissue characterization, compared with that of MR imaging, and the radiation risk to the fetus; this risk often outweighs the benefit. The primary role for CT is in the evaluation of trauma and gestational trophoblastic disease, for which it allows characterization of the primary lesion and distant metastases., ((c) RSNA, 2009.)
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- 2009
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21. MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.
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Yuval, Jonathan, Patil, Sujata, Gangai, Natalie, Omer, Dana, Akselrod, Dmitriy, Fung, Alice, Harmath, Carla, Kampalath, Rony, Krehbiel, Kyle, Lee, Sonia, Liu, Peter, Millet, John, OMalley, Ryan, Purysko, Andrei, Veniero, Joseph, Wasnik, Ashish, Garcia-Aguilar, Julio, and Gollub, Marc
- Subjects
MRI ,Neoadjuvant treatment ,Organ preservation ,Rectal cancer ,Watch and wait ,Humans ,Neoadjuvant Therapy ,Rectal Neoplasms ,Magnetic Resonance Imaging ,Lymph Nodes ,Remission Induction ,Chemoradiotherapy ,Neoplasm Staging ,Treatment Outcome ,Retrospective Studies - Abstract
OBJECTIVES: A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them. METHODS: Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2 years. RESULTS: We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated. CONCLUSIONS: MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients. KEY POINTS: • The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients scans were interpreted with high accuracy and low variability, suggesting that these patients pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.
- Published
- 2023
22. Effect of anthracycline therapy on myocardial function and markers of fibrotic remodelling in childhood cancer survivors.
- Author
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Mawad, Wadi, Mertens, Luc, Pagano, Joseph J, Riesenkampff, Eugenie, Reichert, Marjolein J E, Mital, Seema, Kantor, Paul F, Greenberg, Mark, Liu, Peter, Nathan, Paul C, and Grosse-Wortmann, Lars
- Subjects
BIOMARKERS ,ECHOCARDIOGRAPHY ,CARDIOTOXICITY ,ANTHRACYCLINES ,VENTRICULAR ejection fraction ,MYOCARDIUM ,HEART cells ,MYOCARDIAL infarction ,FIBROSIS ,MAGNETIC resonance imaging ,TUMORS in children ,CANCER patients ,HEART ventricles ,HEART physiology ,STROKE volume (Cardiac output) - Abstract
Aims Anthracyclines are a cornerstone of paediatric cancer treatment. We aimed to quantify myocardial cardiac magnetic resonance (CMR) native T1 (NT1) and extracellular volume fraction (ECV) as markers of fibrosis in a cohort of childhood cancer survivors (CCS). Methods and results A cohort of CCS in remission underwent CMR T1 mapping. Diastolic function was assessed by echocardiography. Results were compared to a cohort of normal controls of similar age and gender. Fifty-five CCS and 46 controls were included. Both groups had similar mean left ventricular (LV) NT1 values (999 ± 36 vs. 1007 ± 32 ms, P = 0.27); ECV was higher (25.6 ± 6.9 vs. 20.7 ± 2.4%, P = 0.003) and intracellular mass was lower (37.5 ± 8.4 vs. 43.3 ± 9.9g/m
2 , P = 0.02) in CCS. The CCS group had lower LV ejection fraction (EF) and LV mass index with otherwise normal diastolic function in all but one patient. The proportion of subjects with elevated ECV compared to controls did not differ between subgroups with normal or reduced LV EF (22% vs. 28%; P = 0.13) and no correlations were found between LVEF and ECV. While average values remained within normal range, mitral E / E ′ (6.6 ± 1.6 vs. 5.9 ± 0.9, P = 0.02) was higher in CCS. Neither NT1 nor ECV correlated with diastolic function indices or cumulative anthracycline dose. Conclusions There is evidence for mild diffuse extracellular volume expansion in some asymptomatic CCS; myocyte loss could be part of the mechanism, accompanied by subtle changes in systolic and diastolic function. These findings suggest mild myocardial damage and remodelling after anthracycline treatment in some CCS which requires continued monitoring. [ABSTRACT FROM AUTHOR]- Published
- 2021
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23. Normal MR Anatomy, An Issue of Magnetic Resonance Imaging Clinics
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Liu, Peter S. and Liu, Peter S.
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- Cross-sectional imaging, Human anatomy, Magnetic resonance imaging
- Abstract
This issue provides an overview of anatomy for the practicing radiologist using MR. Neuroanatomy is covered in separate articles on the brain, neck, spine, and skull base. Body imaging is reviewed in articles on chest, abdomen, breast, and pelvis, and finally, the musculoskeletal system is thoroughly displayed by articles on shoulder, elbow, wrist and hand, knee, and ankle and foot. Long bones of the upper and lower extremities are reviewed in separate articles as well.
- Published
- 2011
24. Novel approaches to the prediction, diagnosis and treatment of cardiac late effects in survivors of childhood cancer: a multi-centre observational study.
- Author
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Skitch, Amy, Mital, Seema, Mertens, Luc, Liu, Peter, Kantor, Paul, Grosse-Wortmann, Lars, Manlhiot, Cedric, Greenberg, Mark, and Nathan, Paul C.
- Subjects
HEART disease diagnosis ,THERAPEUTICS ,HEART diseases ,ANTHRACYCLINES ,CHILDHOOD cancer ,CANCER patients ,CARDIOTOXICITY ,ANTINEOPLASTIC agents ,COMPARATIVE studies ,ECHOCARDIOGRAPHY ,MAGNETIC resonance imaging ,RESEARCH methodology ,MEDICAL cooperation ,PROGNOSIS ,RESEARCH ,TUMORS ,GENOMICS ,EVALUATION research ,DISEASE complications - Abstract
Background: Anthracycline-induced cardiac toxicity is a cause of significant morbidity and early mortality in survivors of childhood cancer. Current strategies for predicting which children are at greatest risk for toxicity are imperfect and diagnosis of cardiac injury is usually made relatively late in the natural history of the disease. This study aims to identify genomic, biomarker and imaging parameters that can be used as predictors of risk or aid in the early diagnosis of cardiotoxicity.Methods: This is a prospective longitudinal cohort study that recruited two cohorts of pediatric cancer patients at six participating centres: (1) an Acute Cohort of children newly diagnosed with cancer prior to starting anthracycline therapy (n = 307); and (2) a Survivor Cohort of long-term survivors of childhood cancer with past exposure to anthracycline (n = 818). The study team consists of three collaborative cores. The Genomics Core is identifying genomic variations in anthracycline metabolism and in myocardial response to injury that predispose children to treatment-related cardiac toxicity. The Biomarker Core is identifying existing and novel biomarkers that allow for early diagnosis and prognosis of anthracycline-induced cardiac toxicity. The Imaging Core is identifying echocardiographic and cardiac magnetic resonance (CMR) imaging parameters that correspond to early signs of cardiac dysfunction and remodeling and precede global dysfunction and clinical symptoms. The data generated by the cores will be combined to create an integrated risk-prediction model aimed at more accurate identification of children who are most susceptible to anthracycline toxicity.Discussion: We aim to identify genomic risk factors that predict risk for anthracycline cardiotoxicity pre-exposure and imaging and biomarkers that facilitate early diagnosis of cardiac injury. This will facilitate a personalized approach to identifying at-risk children with cancer who may benefit from cardio- protective strategies during therapy, and closer surveillance and earlier initiation of medications to preserve heart function after cancer therapy.Trial Registration: NCT01805778 . Registered 28 February 2013; retrospectively registered. [ABSTRACT FROM AUTHOR]- Published
- 2017
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25. Modeling of glioma growth using modified reaction-diffusion equation on brain MR images.
- Author
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Zhang, Yanying, Liu, Peter X., and Hou, Wenguo
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REACTION-diffusion equations , *MAGNETIC resonance imaging , *GLIOMAS , *BRAIN imaging , *BRAIN tumors , *DIFFUSION coefficients - Abstract
• Simulation of diffusion and proliferation of brain tumors • Calculation of model coefficients based on patient-specific anatomy • Construction of a parameter space using inverse distance-weighted interpolation • Description of spatial distribution of proliferation and diffusion coefficients Background and Objective: Modeling of glioma growth and evolution is of key importance for cancer diagnosis, predicting clinical progression and improving treatment outcomes of neurosurgery. However, existing models are unable to characterize spatial variations of the proliferation and infiltration of tumor cells, making it difficult to achieve accurate prediction of tumor growth. Methods: In this paper, a new growth model of brain tumor using a reaction-diffusion equation on brain magnetic resonance images is proposed. Both the heterogeneity of brain tissue and the density of tumor cells are used to estimate the proliferation and diffusion coefficients of brain tumor cells. The diffusion coefficient that characterizes tumor diffusion and infiltration is calculated based on the ratio of tissues (white and gray matter), while the proliferation coefficient is evaluated using the spatial gradient of tumor cells. In addition, a parameter space is constructed using inverse distance weighted interpolation to describe the spatial distribution of proliferation coefficient.Results: The glioma growth predicted by the proposed model were tested by comparing with the real magnetic resonance images of the patients. Experiments and simulation results show that the proposed method achieves accurate modeling of glioma growth. The interpolation-based growth model has higher average dice score of 0.0647 and 0.0545, and higher average Jaccard index of 0.0673 and 0.0573, respectively, compared to the uniform- and gradient-based growth models. Conclusions: The experimental results demonstrate the feasibility of calculating the proliferation and diffusion coefficients of the growth model based on patient-specific anatomy. The parameter space that characterizes spatial distribution of proliferation and diffusion coefficients is established and incorporated into the simulation of glioma growth. It enables to obtain patient-specific models about glioma growth by estimating and calibrating only a few model parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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26. Advances in Biliary Imaging.
- Author
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Downey, Ryan T., Wells, Shane A., and Liu, Peter S.
- Subjects
BILIARY tract ,PATHOLOGY ,ENDOSCOPIC retrograde cholangiopancreatography ,TOMOGRAPHY ,MAGNETIC resonance imaging ,ENDOSCOPIC surgery - Abstract
Noninvasive imaging of the biliary tree has undergone substantial technological innovation over the past two decades and has led to increased usage in the diagnostic evaluation of suspected biliary tract pathology. While endoscopic retrograde cholangiopancreatography has been regarded as the gold standard for diagnostic evaluation of the pancreaticobiliary tree and offers the benefit of therapeutic intervention, technical failure and complications rates are not insignificant. Multidetector computed tomography (CT) and magnetic resonance imaging (MRI) can depict the biliary tree with high technical success and minimal procedural risk. The development of helical scanning technique and multidetector technology has revolutionized CT, allowing volumetric data acquisition with sub-millimeter voxels. Evaluation of the biliary tree by MRI relies on one of several available magnetic resonance cholangiopancreatography (MRCP) protocols, which offer superior contrast resolution versus CT. Thick slab single-section and thin slice multi-section techniques provide satisfactory complementary techniques that can obtained very quickly, including in uncooperative patients. Recent innovations in MRI sequence design and scanner technology have resulted in improved MRCP techniques, including newer 3D T2-weighted techniques and high field strength imaging at 3.0 Tesla. Newer contrast agents excreted into the hepatobiliary tree may provide a valuable adjunct to patients undergoing liver MRI for other reasons, including preoperative transplant evaluation or suspected postoperative complication. The diagnostic performance of both CT and MRI has been proven for many biliary clinical applications, including calculi, strictures, and tumor staging. [ABSTRACT FROM AUTHOR]
- Published
- 2010
27. Hepatic capsular retraction: An updated MR imaging review.
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Panick, Catherine E.P., Ward, Ryan D., Coppa, Christopher, and Liu, Peter S.
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MAGNETIC resonance imaging , *DIFFERENTIAL diagnosis , *DIAGNOSTIC imaging , *LIVER , *THEATER reviews , *SURGICAL arteriovenous shunts , *COMPUTED tomography , *HEMANGIOMAS , *HEPATOCELLULAR carcinoma , *LIVER tumors , *PROSTATE , *URETHRA - Abstract
Hepatic capsular retraction is a morphologic descriptor that refers to invagination or focal flattening of the typical smooth contour of the liver capsule. It is an uncommon finding that, when combined with other imaging features and clinical context, can help to refine the differential diagnosis in patients with liver lesions. Although this descriptor has historically been used in reference to a small subset of benign and malignant lesions, the differential has since been expanded with the discovery of new entities causing capsular retraction as well as with novel and increased use of liver-directed treatment techniques. Additionally, modern imaging techniques now allow for improved detection and characterization of capsular retraction. In this review, we discuss these common and uncommon causes of capsular retraction, with an emphasis on findings from body MRI. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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28. Cardiovascular Magnetic Resonance in Myocarditis: A JACC White Paper
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Friedrich, Matthias G., Sechtem, Udo, Schulz-Menger, Jeanette, Holmvang, Godtfred, Alakija, Pauline, Cooper, Leslie T., White, James A., Abdel-Aty, Hassan, Gutberlet, Matthias, Prasad, Sanjay, Aletras, Anthony, Laissy, Jean-Pierre, Paterson, Ian, Filipchuk, Neil G., Kumar, Andreas, Pauschinger, Matthias, and Liu, Peter
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CARDIOVASCULAR system , *MYOCARDITIS , *NONINVASIVE diagnostic tests , *MEDICAL protocols , *INFLAMMATION , *MEDICAL societies , *CONSENSUS (Social sciences) , *DIAGNOSIS , *PATIENTS , *MAGNETIC resonance imaging - Abstract
Cardiovascular magnetic resonance (CMR) has become the primary tool for noninvasive assessment of myocardial inflammation in patients with suspected myocarditis. The International Consensus Group on CMR Diagnosis of Myocarditis was founded in 2006 to achieve consensus among CMR experts and develop recommendations on the current state-of-the-art use of CMR for myocarditis. The recommendations include indications for CMR in patients with suspected myocarditis, CMR protocol standards, terminology for reporting CMR findings, and diagnostic CMR criteria for myocarditis (i.e., “Lake Louise Criteria”). [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
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