Jie Deng

Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, United States

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Publications (4)9.63 Total impact

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    ABSTRACT: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. The gold standard for diagnosis is liver biopsy. MRI is a non-invasive imaging method to provide quantitative measurement of hepatic fat content. The methodology is particularly appealing for the pediatric population because of its rapidity and radiation-free imaging techniques.
    Pediatric Radiology 05/2014; · 1.57 Impact Factor
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    ABSTRACT: Phase contrast magnetic resonance imaging (MRI) is a powerful tool for evaluating vessel blood flow. Inherent errors in acquisition, such as phase offset, eddy currents and gradient field effects, can cause significant inaccuracies in flow parameters. These errors can be rectified with the use of background correction software. To evaluate the performance of an automated phase contrast MRI background phase correction method in children and young adults undergoing cardiac MR imaging. We conducted a retrospective review of patients undergoing routine clinical cardiac MRI including phase contrast MRI for flow quantification in the aorta (Ao) and main pulmonary artery (MPA). When phase contrast MRI of the right and left pulmonary arteries was also performed, these data were included. We excluded patients with known shunts and metallic implants causing visible MRI artifact and those with more than mild to moderate aortic or pulmonary stenosis. Phase contrast MRI of the Ao, mid MPA, proximal right pulmonary artery (RPA) and left pulmonary artery (LPA) using 2-D gradient echo Fast Low Angle SHot (FLASH) imaging was acquired during normal respiration with retrospective cardiac gating. Standard phase image reconstruction and the automatic spatially dependent background-phase-corrected reconstruction were performed on each phase contrast MRI dataset. Non-background-corrected and background-phase-corrected net flow, forward flow, regurgitant volume, regurgitant fraction, and vessel cardiac output were recorded for each vessel. We compared standard non-background-corrected and background-phase-corrected mean flow values for the Ao and MPA. The ratio of pulmonary to systemic blood flow (Qp:Qs) was calculated for the standard non-background and background-phase-corrected data and these values were compared to each other and for proximity to 1. In a subset of patients who also underwent phase contrast MRI of the MPA, RPA, and LPA a comparison was made between standard non-background-corrected and background-phase-corrected mean combined flow in the branch pulmonary arteries and MPA flow. All comparisons were performed using the Wilcoxon sign rank test (α = 0.05). Eighty-five children and young adults (mean age 14 years; range 10 days to 32 years) met the criteria for inclusion. Background-phase-corrected mean flow values for the Ao and MPA were significantly lower than those for non-background-corrected standard Ao (P = 0.0004) and MPA flow values (P < 0.0001), respectively. However, no significant difference was seen between the standard non-background (P = 0.295) or background-phase-corrected (P = 0.0653) mean Ao and MPA flow values. Neither the mean standard non-background-corrected (P = 0.408) nor the background-phase-corrected (P = 0.0684) Qp:Qs was significantly different from 1. However in the 27 patients with standard non-background-corrected data, the difference between the Ao and MPA flow values was greater than 10%. There were 19 patients with background-phase-corrected data in which the difference between the Ao and MPA flow values was greater than 10%. In the subset of 43 patients who underwent MPA and branch pulmonary artery phase contrast MRI, the sum of the standard non-background-corrected mean RPA and LPA flow values was significantly different from the standard non-background-corrected mean MPA flow (P = 0.0337). The sum of the background-phase-corrected mean RPA and LPA flow values was not significantly different from the background-phase-corrected mean MPA flow value (P = 0.1328), suggesting improvement in pulmonary artery flow calculations using background-phase-correction. Our data suggest that background phase correction of phase contrast MRI data does not significantly change Qp:Qs quantification, and there are residual errors in expected Qp:Qs quantification despite background phase correction. However the use of background phase correction does improve quantification of MPA flow relative to combined RPA and LPA flow. Further work is needed to validate these findings in other patient populations, using other MRI units, and across vendors.
    Pediatric Radiology 12/2013; · 1.57 Impact Factor
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    ABSTRACT: The purpose was to propose and evaluate a semiautomatic postprocessing method to measure liver R2(⁎) values in patients with a broad range of liver iron content. Multiecho gradient echo magnetic resonance images were acquired in patients diagnosed with thalassemia or other types of congenital anemias. Liver R2(⁎) values were measured using a routine manually defined region-of-interest (mROI) method and a semiautomatic (SA) method. In the semiautomatic method, pixelwise (pSA) and averaged (aSA) signal fitting was performed on the segmented liver tissues after hepatic vessel extraction. The pixelwise fitting approach resulted in a liver R2(⁎) map with an overlay of nonfitted pixels associated with noise performance. The following aSA approach derived overall R2(⁎) by fitting the averaged signal intensities of all pixels within the liver ROI excluding vessels and nonfitted pixels. The measurement accuracy and interobserver agreement using mROI and the two semiautomatic approaches (pSA and aSA) were evaluated. In a total of 45 exams with R2(⁎) ranging from 30 to 1500 s(-1), the R2(⁎) measurements using all three methods were overall highly correlated and concordant with each other. R2(⁎) values measured by aSA were consistently higher than those measured by mROI. At lower R2(⁎) (<1000 s(-1)), R2(⁎) values measured by pSA were consistent with aSA but higher than mROI; with increasing R2(⁎), the pSA method became less stable and underestimated R2(⁎) due to increased noise level. The interobserver agreement was higher for the aSA method compared to pSA and mROI. The semiautomatic postprocessing method provides a promising tool for reliable liver R2(⁎) measurement with additional information for overall evaluation of iron distribution and measurement confidence. This method may offer the potential of reducing interoperator variability and improving diagnostic confidence in patients with liver iron overload.
    Magnetic Resonance Imaging 03/2012; 30(6):799-806. · 2.06 Impact Factor
  • Source
    Journal of Cardiovascular Magnetic Resonance 01/2010; · 4.44 Impact Factor

Publication Stats

3 Citations
9.63 Total Impact Points

Institutions

  • 2013
    • Ann & Robert H. Lurie Children's Hospital of Chicago
      Chicago, Illinois, United States
  • 2010–2012
    • Children's Memorial Hospital
      Chicago, Illinois, United States