Octavia Bane

Interplatform reproducibility of liver and spleen stiffness measured with MR elastography.

To assess interplatform reproducibility of liver stiffness (LS) and spleen stiffness (SS) measured with magnetic resonance elastography (MRE) based on a 2D gradient echo (GRE) sequence.

Magnetic Resonance Elastography of the Liver: Qualitative and Quantitative Comparison of Gradient Echo and Spin Echo Echoplanar Imaging Sequences

ObjectiveThe aim of this study was to compare 2-dimensional (2D) gradient recalled echo (GRE) and 2D spin echo echoplanar imaging (SE-EPI) magnetic resonance elastography (MRE) sequences of the liver in terms of image quality and quantitative liver stiffness (LS) measurement. Materials and MethodsThis prospective study involved 50 consecutive subjects (male/female, 33/17; mean age, 58 years) who underwent liver magnetic resonance imaging at 3.0 T including 2 MRE sequences, 2D GRE, and 2D SE-EPI (acquisition time 56 vs 16 seconds, respectively). Image quality scores were assessed by 2 independent observers based on wave propagation and organ coverage on the confidence map (range, 0–15). A third observer measured LS on stiffness maps (in kilopascal). Mean LS values, regions of interest size (based on confidence map), and image quality scores between SE-EPI and GRE-MRE were compared using paired nonparametric Wilcoxon test. Reproducibility of LS values between the 2 sequences was assessed using intraclass coefficient correlation, coefficient of variation, and Bland-Altman limits of agreement. T2* effect on image quality was assessed using partial Spearman correlation. ResultsThere were 4 cases of failure with GRE-MRE and none with SE-EPI-MRE. Image quality scores and region of interest size were significantly higher using SE-EPI-MRE versus GRE-MRE (P < 0.0001 for both measurements and observers). Liver stiffness measurements were not significantly different between the 2 sequences (3.75 ± 1.87 kPa vs 3.55 ± 1.51 kPa, P = 0.062), were significantly correlated (intraclass coefficient correlation, 0.909), and had excellent reproducibility (coefficient of variation, 10.2%; bias, 0.023; Bland-Altman limits of agreement, −1.19; 1.66 kPa). Image quality scores using GRE-MRE were significantly correlated with T2* while there was no correlation for SE-EPI-MRE. ConclusionsOur data suggest that SE-EPI-MRE may be a better alternative to GRE-MRE. The diagnostic performance of SE-EPI-MRE for detection of liver fibrosis needs to be assessed in a future study.

Prospective comparison of magnetic resonance imaging to transient elastography and serum markers for liver fibrosis detection

Establishing accurate non‐invasive methods of liver fibrosis quantification remains a major unmet need. Here, we assessed the diagnostic value of a multiparametric magnetic resonance imaging (MRI) protocol including diffusion‐weighted imaging (DWI), dynamic contrast‐enhanced (DCE)‐MRI and magnetic resonance elastography (MRE) in comparison with transient elastography (TE) and blood tests [including ELF (Enhanced Liver Fibrosis) and APRI] for liver fibrosis detection.

Intravoxel incoherent motion diffusion-weighted imaging of hepatocellular carcinoma: Is there a correlation with flow and perfusion metrics obtained with dynamic contrast-enhanced MRI?

To assess the correlation between intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) metrics in hepatocellular carcinoma (HCC) and liver parenchyma.

Assessment of renal function using intravoxel incoherent motion diffusion-weighted imaging and dynamic contrast-enhanced MRI.

To assess the correlation between each of intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) metrics in renal parenchyma with renal function, in a cohort of patients with chronic liver disease.

3D T1 relaxometry pre and post gadoxetic acid injection for the assessment of liver cirrhosis and liver function

PURPOSE To assess the diagnostic value of a 3D dual-flip-angle (DFA) T1 mapping technique with whole liver coverage before and after gadoxetic acid injection for assessment of cirrhosis and liver function, compared to blood tests (APRI: aspartate aminotransferase-to-platelet ratio index). MATERIALS AND METHODS A total of 133 patients who underwent gadoxetic acid-enhanced liver MRI including a 3D FLASH DFA-T1 mapping sequence before and 20min post-contrast (hepatobiliary phase, HBP) were included in this retrospective IRB approved study. T1 values (msec) were measured on pre-contrast and during HBP in liver parenchyma, ΔT1 (%) was calculated as [(T1 pre-T1 post)/T1 pre]×100. T1 and ΔT1 values were compared between cirrhotic and non-cirrhotic patients and between patients stratified using Child-Pugh and Model for End-Stage Liver Disease (MELD) scores using Mann-Whitney U test. Diagnostic performance of T1 mapping parameters vs. APRI for diagnosing cirrhosis and for assessing degree of liver dysfunction was evaluated using ROC analysis. RESULTS Fifty non-cirrhotic and 83 cirrhotic patients [Child-Pugh A (n=41), B (n=31) and C (n=11)] were included. There was no significant difference in pre-contrast T1 values between cirrhotic and non-cirrhotic patients. T1-HBP and ΔT1 values were significantly different in patients with cirrhosis (p<0.0001) and higher MELD scores (>17) (p=0.003). ΔT1 showed significant strong correlations with Child-Pugh and MELD scores (r=-0.7, p<0.0001; r=-0.56, p<0.001 respectively). Similar AUCs (p=0.9) for detection of liver cirrhosis were observed for T1 HBP (0.83), ΔT1 (0.86) and APRI (0.85); however APRI showed limited sensitivity (≤55%) in comparison with ΔT1 (74.7%) and T1 HBP (80.7%). CONCLUSION 3D DFA-T1 mapping sequence used before and after gadoxetic acid injection is useful for the diagnosis of cirrhosis and for the assessment of liver function.

Quantification of hepatocellular carcinoma heterogeneity with multiparametric magnetic resonance imaging

Tumour heterogeneity poses a significant challenge for treatment stratification. The goals of this study were to quantify heterogeneity in hepatocellular carcinoma (HCC) using multiparametric magnetic resonance imaging (mpMRI), and to report preliminary data correlating quantitative MRI parameters with advanced histopathology and gene expression in a patient subset. Thirty-two HCC patients with 39 HCC lesions underwent mpMRI including diffusion-weighted imaging (DWI), blood-oxygenation-level-dependent (BOLD), tissue-oxygenation-level-dependent (TOLD) and dynamic contrast-enhanced (DCE)-MRI. Histogram characteristics [central tendency (mean, median) and heterogeneity (standard deviation, kurtosis, skewness) MRI parameters] in HCC and liver parenchyma were compared using Wilcoxon signed-rank tests. Histogram data was correlated between MRI methods in all patients and with histopathology and gene expression in 14 patients. HCCs exhibited significantly higher intra-tissue heterogeneity vs. liver with all MRI methods (P < 0.030). Although central tendency parameters showed significant correlations between MRI methods and with each of histopathology and gene expression, heterogeneity parameters exhibited additional complementary correlations between BOLD and DCE-MRI and with histopathologic hypoxia marker HIF1α and gene expression of Wnt target GLUL, pharmacological target FGFR4, stemness markers EPCAM and KRT19 and immune checkpoint PDCD1. Histogram analysis combining central tendency and heterogeneity mpMRI features is promising for non-invasive HCC characterization on the imaging, histologic and genomics levels.

Liver fat quantification: Comparison of dual-echo and triple-echo chemical shift MRI to MR spectroscopy

PURPOSE To assess the diagnostic value of MRI using dual-echo (2PD) and triple-echo (3PD) chemical shift imaging for liver fat quantification against multi-echo T2 corrected MR spectroscopy (MRS) used as the reference standard, and examine the effect of T2(*) imaging on accuracy of MRI for fat quantification. MATERIALS AND METHODS Patients who underwent 1.5T liver MRI that incorporated 2PD, 3PD, multi-echo T2(*) and MRS were included in this IRB approved prospective study. Regions of interest were placed in the liver to measure fat fraction (FF) with 2PD and 3PD and compared with MRS-FF. A random subset of 25 patients with a wide range of MRS-FF was analyzed with an advanced FF calculation method, to prove concordance with the 3PD. The statistical analysis included correlation stratified according to T2(*), Bland-Altman analysis, and calculation of diagnostic accuracy for detection of MRS-FF>6.25%. RESULTS 220 MRI studies were identified in 217 patients (mean BMI 28.0±5.6). 57/217 (26.2%) patients demonstrated liver steatosis (MRS-FF>6.25%). Bland-Altman analysis revealed strong agreement between 3PD and MRS (mean±1.96 SD: -0.5%±4.6%) and weaker agreement between 2PD and MRS (4.7%±16.0%). Sensitivity of 3PD for diagnosing FF> 6.25% was higher than that of 2PD. 3PD-FF showed minor discrepancies (coefficient of variation <10%) from FF measured with the advanced method. CONCLUSION Our large series study validates the use of 3PD chemical shift sequence for detection of liver fat in the clinical environment, even in the presence of T2(*) shortening.

Feasibility and reproducibility of BOLD and TOLD measurements in the liver with oxygen and carbogen gas challenge in healthy volunteers and patients with hepatocellular carcinoma.

To quantify baseline relaxation rates R2* and R1 in the abdomen, their changes after respiratory challenges, and their reproducibility in healthy volunteers and patients with hepatocellular carcinoma (HCC) at 1.5T and 3.0T.

Accuracy, repeatability, and interplatform reproducibility of T1 quantification methods used for DCE‐MRI: Results from a multicenter phantom study

To determine the in vitro accuracy, test‐retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast‐enhanced MRI at 1.5 and 3 T.