Comparison Between a Modified Fast 3-Dimensional Turbo Spin-Echo and Diffusion-Weighted Imaging With Background Suppression in Evaluation of Lumbosacral Plexus and Its Branches.

OBJECTIVES: To compare the fast 3-dimensional NerveVIEW (3D NerveVIEW) with diffusion-weighted imaging with background suppression (DWIBS) in imaging of lumbosacral plexus and its branches. METHODS: A prospective study was performed on 30 healthy volunteers and patients who had undergone compressed sensing 3D NerveVIEW and DWIBS scans. There were 11 healthy subjects, 15 patients with lumbar disc herniation, and 4 patients with chronic inflammatory demyelinating polyradiculoneuropathy. Image quality was rated using a 4-point subjective scale. Quantitative evaluation of the nerves was done by measuring signal-to-noise ratio, contrast-to-noise ratio, and signal-to-background ratio, and the consistency in the measurements of nerve root cross-sectional areas was also assessed. The differences of signal-to-noise ratio, contrast-to-noise ratio, signal-to-background ratio, and the scores of image quality between 2 sequences were compared. RESULTS: The overall average image quality score of 3D NerveVIEW was significantly higher than that of DWIBS (2.72 ± 0.45 and 2.45 ± 0.81, respectively; P < 0.01). In terms of individual nerves, there was no significant difference between the 2 sequences in the display of the nerves from L2 to S1; however, 3D NerveVIEW was significantly better than DWIBS in demonstration of the S2-S3 nerves, as well as the nerve details. Regarding quantitative measurements, these sequences achieved comparable results with excellent interobserver agreements. CONCLUSION: Fast 3D NerveVIEW was superior to DWIBS with improved conspicuity of small distal nerves of S2-S3 and nerve details.

Time-of-Flight Intracranial MRA at 3 T versus 5 T versus 7 T: Visualization of Distal Small Cerebral Arteries.

Background Three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) at 7 T has been reported to have high image quality for visualizing small perforating vessels. However, B1 inhomogeneity and more physiologic considerations limit its applications. Angiography at 5 T may provide another choice for intracranial vascular imaging. Purpose To evaluate the image quality and cerebrovascular visualization of 5-T 3D TOF MRA for visualizing intracranial small branch arteries. Materials and Methods Participants (healthy volunteers or participants with a history of ischemic stroke undergoing intracranial CT angiography or MRA for identifying steno-occlusive disease) were prospectively included from September 2021 to November 2021. Each participant underwent 3-T, 5-T, and 7-T 3D TOF MRA with use of customized MR protocols within 48 hours. Radiologist scoring from 0 (invisible) to 3 (excellent) and quantitative assessment were obtained to evaluate the image quality. The Friedman test was used for comparison of characteristics derived from 3 T, 5 T, and 7 T. Results A total of 12 participants (mean age ± SD, 38 years ± 9; nine men) were included. Visualizations of the distal arteries and small vessels at 5-T TOF MRA were significantly higher than those at 3 T (median score: 3.0 vs 2.0, all P < .001 for distal segments and lenticulostriate artery; median score: 2.0 vs 0, P < .001 for pontine artery). The total length of small vessel branches detected at 5 T was larger than that at 3 T (5.1 m ± 0.7 vs 1.9 m ± 0.4; P < .001). However, there was no evidence of a significant difference compared with 7 T in either the depiction of distal segments and small vessel branches (average median score, 2.5; all P > .05) or the quantitative measurements (total length, 5.6 m ± 0.5; P = .41). Conclusion Three-dimensional time-of-flight MR angiography at 5 T presented the capability to provide superior visualization of distal large arteries and small vessel branches (in terms of subjective and quantitative assessment) to 3 T and had image quality similar to 7 T. © RSNA, 2022 Online supplemental material is available for this article. An earlier incorrect version appeared online. This article was corrected on September 14, 2022.

Treatment efficacy and safety of adalimumab versus tocilizumab in patients with active and severe Takayasu arteritis: an open-label study.

OBJECTIVE: This study aimed to compare the efficacy and safety of adalimumab (ADA) versus tocilizumab (TCZ) in patients with Takayasu arteritis (TAK). METHODS: This was a randomized, controlled, open-label study. Forty patients with active and severe TAK were enrolled. They were treated with ADA (n = 21) combined with glucocorticoids (GCs) and methotrexate (MTX) or TCZ (n = 19) combined with GCs and MTX. The planned follow-up duration was 12 months. The primary end point was the efficacy rate (ER) at 6 months. The secondary endpoints included ER at 9 and 12 months, relapse rate, GC tapering, adverse effects, and life quality changes during treatment. RESULTS: In the intention-to-treat (ITT) population, the ER at 6 months was higher in the ADA group (85.71% vs 52.63%, P= 0.02). A similar direction of effect was noted in the per-protocol set (89.47% vs 62.50%, P= 0.06). The percentages of patients who achieved a GC dose of ≤ 10 mg/day at 6 months were similar between the ADA and TCZ groups (47.37% vs 43.75%, P= 0.83). The ERs at 9 and 12 months were similar between the two groups (P> 0.05). During the first 12 months of treatment, the relapse rate and adverse event incidence were comparable between the two groups (ADA vs TCZ: 9.52% vs 10.53%, P= 0.96; 38.10% vs 47.37%, P= 0.55, respectively). CONCLUSION: ADA combined with GCs and MTX may be more efficacious than TCZ combined with GCs and MTX among patients with active and severe TAK. TRIAL REGISTRATION: Clinicaltrials.gov; NCT04300686.

The clinical feasibility of artificial intelligence-assisted compressed sensing single-shot fluid-attenuated inversion recovery (ACS-SS-FLAIR) for evaluation of uncooperative patients with brain diseases: comparison with the conventional T2-FLAIR with parallel imaging.

BACKGROUND: Satisfactory magnetic resonance imaging (MRI) of those patients with involuntary head motion due to brain diseases is essential in avoiding missed diagnosis and guiding treatment. PURPOSE: To investigate the clinical feasibility of artificial intelligence-assisted compressed sensing single-shot fluid-attenuated inversion recovery (ACS-SS-FLAIR) in evaluating patients with involuntary head motion due to brain diseases, compared with the conventional T2-FLAIR with parallel imaging (PI-FLAIR). MATERIAL AND METHODS: A total of 33 uncooperative patients with brain disease were prospectively enrolled. Two readers independently reviewed images acquired with ACS-SS-FLAIR and PI-FLAIR at a 3.0-T MR scanner. In the aspects of qualitative evaluation of image quality, overall image quality and lesion conspicuity of ACS-SS-FLAIR and PI-FLAIR were assessed and then statistically compared by paired Wilcoxon rank-sum test. For quantitative evaluation, the relative contrast of lesion-to-cerebral parenchyma were calculated and compared. RESULTS: Overall image quality scores of ACS-SS-FLAIR evaluated by two readers were 2.94 ± 0.24 and 2.91 ± 0.29, respectively, both of which were significantly higher than that of PI-FLAIR, respectively (P < 0.001 and <0.001). Lesion conspicuity scores of were 2.74 ± 0.47 and 2.79 ± 0.44, both of which were significantly higher than that of PI-FLAIR, respectively (P < 0.001 and <0.001). In the quantitative evaluation for image quality, the relative contrast of lesion-to-cerebral parenchyma was 0.34 ± 0.09 in the ACS-SS-FLAIR sequence, significantly larger than that in the PI-FLAIR sequence (P = 0.001). CONCLUSION: The ACS-SS-FLAIR sequence is clinically feasible in the MRI workup of those patients with involuntary head motion due to brain diseases, showing shorter image acquisition time and better image quality compared with conventional PI-FLAIR.

Preliminary Experience of 5.0 T Higher Field Abdominal Diffusion-Weighted MRI: Agreement of Apparent Diffusion Coefficient With 3.0 T Imaging.

BACKGROUND: Recently, a prototype 5.0 T whole-body MRI scanner was developed. A 5.0 T diffusion-weighted imaging (DWI) may help overcome the issues that limit 3.0 T DWI. PURPOSE: To evaluate the feasibility of 5.0 T high-field DWI in the upper abdomen and assess the agreement of the apparent diffusion coefficient (ADC) with that from 3.0 T abdominal DWI. STUDY TYPE: Prospective proof of concept. POPULATION: Nine volunteers (mean ± SD age: 37.3 ± 7.0 years, 8 M), eight healthy and one with liver and kidney cysts. FIELD STRENGTH/SEQUENCE: 3.0 T and 5.0 T; respiratory-triggered spin-echo echo-planar-imaging (SE-EPI)-based DWI sequence. ASSESSMENT: Subjective image quality scores. The ADC values in abdominal organs (liver, pancreas, spleen, and kidney) were measured by two observers for evaluating the interobserver and interfield agreement. STATISTICAL TESTS: Wilcoxon-rank sum test, Bland-Altman analysis, intraclass correlation coefficients (ICCs), and coefficients of variation (CVs). RESULTS: The 5.0 T DWI displayed an increase in subjective image quality score compared to 3.0 T DWI without the significant difference (3.0 T DWI: 3.50 ± 0.47, 5.0 T DWI: 3.72 ± 0.42, P = 0.157). Both the interfield and interobserver agreements of ADC values were substantial to excellent (ICCs = 0.640-0.902). For all four upper abdominal organs, there were no significant differences between the ADC values measured by two observers and between the ADC values of 3.0 T and 5.0 T DWI (P = 0.134-1.000). The CVs of ADC measurements from 3.0 T and 5.0 T DWI were all less than 15.0% (6.7%-14.2%). DATA CONCLUSION: The substantial to excellent agreements between the ADC values measured with 3.0 T and 5.0 T DWI for liver, pancreas, spleen, and kidney suggested that 5.0 T DWI can be applied for abdominal imaging. The ADC values from 5.0 T abdominal DWI hold the potential to serve as the quantitative markers for clinical investigations. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

The prognostic value of global myocardium strain by CMR-feature tracking in immune checkpoint inhibitor-associated myocarditis.

OBJECTIVES: Immune checkpoint inhibitor (ICI)-associated myocarditis is a potentially fatal complication. Sparse published researches evaluated the prognostic value of cardiovascular magnetic resonance feature tracking (CMR-FT) for ICI-associated myocarditis. METHODS: In the single-center retrospective study, 52 patients with ICI-associated myocarditis and CMR were included from August 2018 to July 2021. The ICI-associated myocarditis was diagnosed by using the clinical criteria of the European Society of Cardiology guidelines. Major adverse cardiovascular events (MACE) were comprised of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. RESULTS: During a median follow-up of 171 days, 14 (27%) patients developed MACE. For patients with MACE, the global circumferential strain (GCS), global radial strain (GRS), global longitudinal strain (GLS), and left ventricular ejection fraction (LVEF) were significantly worse and native T1 values and late gadolinium enhancement (LGE) extent were significantly increased, compared with patients without MACE (p < 0.05). The GLS remained the independent factor associated with a higher risk of MACE (hazard ratio (HR): 2.115; 95% confidence interval (CI): 1.379-3.246; p = 0.001) when adjusting for LVEF, LGE extent, age, sex, body mass index, steroid treatment, and prior cardiotoxic chemotherapy or radiation. After adjustment for LVEF, the GLS remained the independent risk factor associated with a higher rate of MACE among patients with a preserved LVEF (HR: 1.358; 95% CI: 1.007-1.830; p = 0.045). CONCLUSIONS: GLS could provide independent prognostic value over GCS, GRS, traditional CMR features, and clinical features in patients with ICI-associated myocarditis. KEY POINTS: • The global circumferential strain (GCS), global radial strain (GRS), and global longitudinal strain (GLS) by cardiovascular magnetic resonance feature tracking were significantly impaired in patients with an immune checkpoint inhibitor (ICI)-associated myocarditis. • GLS was still significantly impaired in patients with preserved left ventricular ejection fraction. • The worse GLS was an independent risk factor over GCS, GRS, traditional CMR features, and clinical features for predicting major adverse cardiovascular events in patients with ICI-associated myocarditis.

T1 Mapping on Gd-EOB-DTPA-Enhanced MRI for the Prediction of Oxaliplatin-Induced Liver Injury in a Mouse Model.

BACKGROUND: Oxaliplatin-induced liver injury (OILI) not only impairs hepatic regeneration but also increases postoperative morbidity and mortality. Therefore, noninvasive, accurate, and early diagnosis of OILI is mandatory. PURPOSE: To evaluate the potential of T1 mapping on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI for assessing OILI in a mouse model. STUDY TYPE: Case control, animal model. ANIMAL MODEL: Thirty oxaliplatin-treated mice and 10 control mice were included. FIELD STRENGTH: Volumetric interpolated breath-hold examination sequence: 3T scanner with a phased-array animal 8-channel coil. T1 mapping before and at hepatobiliary phase (HBP) after injection of Gd-EOB-DTPA were undertaken. ASSESSMENT: T1 relaxation times of the liver parenchyma were measured and the reduction rate (ΔT1 %) was calculated. Histological findings were used as a standard reference. STATISTICAL TESTS: The Kruskal-Wallis test with pairwise comparisons using the Mann-Whitney U-test were applied to compare the parameters across groups. Spearman's rank correlation test and receiver operating characteristics (ROC) analyses were performed. Areas under the curves (AUCs) were compared using the DeLong method. RESULTS: Histologically, mice were classified as normal (n = 10), hepatocellular degeneration without fibrosis (n = 16), and hepatocellular degeneration with fibrosis (n = 14). HBP T1 relaxation time increased with the severity of OILI (rho = 0.60, P < 0.05), and ΔT1 % decreased with the severity of OILI (rho = -0.78, P < 0.05). AUC was 0.92 for ΔT1 % in differentiating hepatocellular degeneration without fibrosis from normal liver, but HBP T1 relaxation time could not distinguish them (P = 0.09). AUCs were 0.96 and 0.95 for HBP T1 relaxation time, and 0.90 and 0.84 for ΔT1 % in discriminating OILI with fibrosis from normal liver and OILI without fibrosis. DATA CONCLUSION: HBP T1 relaxation time and ΔT1 % of Gd-EOB-DTPA enhanced MRI was useful for assessing OILI. ΔT1 % may be more sensitive than HBP T1 relaxation time in detecting early stage of liver injury. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 5.

Free-breathing BLADE acquisition method improves T2-weighted cardiac MR image quality compared with conventional breath-hold turbo spin-echo cartesian acquisition.

BACKGROUND: Cardiac magnetic resonance (MR) has become an essential diagnostic imaging modality in cardiovascular disease. However, the insufficient image quality of traditional breath-hold (BH) T2-weighted (T2W) imaging may compromise its diagnostic accuracy. PURPOSE: To assess the efficacy of the BLADE technique to reduce motion artifacts and improve the image quality. MATERIAL AND METHODS: Free-breathing TSE-T2W imaging sequence with cartesian and BLADE k-space trajectory were acquired in 20 patients. Thirty patients underwent conventional BH turbo spin-echo (TSE) T2W imaging and free-breathing BLADE T2W (FB BLADE-T2W) imaging. Twenty-one patients who had a signal loss of myocardium in BH short-axis T2W turbo inversion recovery (TSE-T2W-TIR) were scanned using free-breathing BLADE T2W turbo inversion recovery (BLADE TSE-T2W-TIR). The overall image quality, blood nulling, and visualization of the heart were scored on a 5-point Likert scale. The signal loss of myocardium, incomplete fat suppression near the myocardium, and the streaking or ghosting artifacts were noted in T2W-TIR sequences additionally. RESULTS: The overall imaging quality, blood nulling, and the visualization of heart structure of FB BLADE-T2W imaging sequence were significantly better than those of FB T2W imaging with Cartesian k-space trajectory and BH TSE-T2W imaging sequence (P<0.01). The FB BLADE TSE-T2W-TIR reduces the myocardium signal dropout (P<0.05), incomplete fat suppression near myocardium (P<0.05), and the streaking and ghosting artifacts (P<0.05) in comparison with the BH TSE-T2W-TIR. CONCLUSIONS: FB BLADE T2W imaging provides improved myocardial visibility, less motion sensitivity, and better image quality. It may be applied in patients who have poor breath-holding capability.

Recurrence After Curative Resection of Hepatitis B Virus-Related Hepatocellular Carcinoma: Diagnostic Algorithms on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging.

Small recurrent hepatocellular carcinoma (HCC) can show atypical imaging patterns, and a specific diagnostic algorithm for HCC is lacking. This study aimed to better characterize postoperative recurrent HCCs <20 mm in size with gadoxetic acid-enhanced magnetic resonance imaging (MRI). We evaluated 373 newly developed nodules after hepatectomy in 204 HCC patients with chronic hepatitis B virus infection. The diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) version 2018 was calculated with gadoxetic acid-enhanced MRI to characterize recurrent HCC. Modified diagnostic algorithms were proposed by combining significant imaging biomarkers related to subcentimeter and 10-19 mm recurrence, and the algorithms were then compared with the LI-RADS system. A total of 256 recurrent HCCs (108 recurrent HCCs <10 mm in size; 148 recurrent HCCs 10-19 mm in size) were confirmed via histology or follow-up imaging. Nonrim arterial phase hyperenhancement (APHE) and 3 LI-RADS ancillary features (AFs; hepatobiliary phase hypointensity, mild-moderate T2 hyperintensity, and restricted diffusion) were significantly related to recurrent HCCs <20 mm in size according to a multivariate analysis. For subcentimeter recurrence, combining at least 2 of the 3 AFs only achieved better specificity (sensitivity, 83.3%; specificity, 87.7%) than the LR-4 category (sensitivity, 88.9%, P = 0.21; specificity, 70.8%, P = 0.006). For 10-19 mm recurrences, combining nonrim APHE and at least 1 of the 3 AFs achieved only a significantly enhanced sensitivity of 85.1% but a lower specificity of 86.5% compared with the LR-5 category (sensitivity: 63.5%, P < 0.001; specificity: 94.2%, P = 0.13). In conclusion, the diagnostic algorithms for subcentimeter and 10-19 mm recurrent HCCs should be stratified. Combining at least 2 AFs demonstrated comparable sensitivity with significantly enhanced specificity compared with the LR-4 category for characterizing subcentimeter recurrence.

Pre-TACE kurtosis of ADCtotal derived from histogram analysis for diffusion-weighted imaging is the best independent predictor of prognosis in hepatocellular carcinoma.

PURPOSE: To determine the feasibility of pre-TACE IVIM imaging based on histogram analysis for predicting prognosis in the treatment of unresectable hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-five patients prospectively underwent 1.5T MRI 1 week before TACE. Histogram metrics for IVIM parameters and ADCs maps between responders and non-responders with mRECIST assessment were compared. Kaplan-Meier, log-rank tests and Cox proportional hazard regression model were used to correlate variables with time to progression (TTP). RESULTS: Mean (p = 0.022), median (p = 0.043), and 25th percentile (p < 0.001) of perfusion fraction (PF), mean (p < 0.001), median (p < 0.001), 25th percentile (p < 0.001) and 75th percentile (p = 0.001) of ADC(0,500), mean (p = 0.005), median (p = 0.008) and 25th percentile (p = 0.039) of ADCtotal were higher, while skewness and kurtosis of PF (p = 0.001, p = 0.005, respectively), kurtosis of ADC(0,500) and ADCtotal (p = 0.005, p = 0.001, respectively) were lower in responders compared to non-responders. Multivariable analysis demonstrated that mRECIST was associated with TTP independently, and kurtosis of ADCtotal had the best predictive performance for disease progression. CONCLUSION: Pre-TACE kurtosis of ADCtotal is the best independent predictor for TTP. KEY POINTS: • mRECIST was associated with TTP independently. • Lower kurtosis and higher mean for ADCs tend to have good response. • Pre-TACE kurtosis of ADC total is the best independent predictor for TTP.

Chronic kidney disease: Pathological and functional evaluation with intravoxel incoherent motion diffusion-weighted imaging.

BACKGROUND: Because chronic kidney disease (CKD) is a worldwide problem, accurate pathological and functional evaluation is required for planning treatment and follow-up. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) can assess both capillary perfusion and tissue diffusion and may be helpful in evaluating renal function and pathology. PURPOSE: To evaluate functional and pathological alterations in CKD by applying IVIM-DWI. STUDY TYPE: Prospective study. SUBJECTS: In all, 72 CKD patients who required renal biopsy and 20 healthy volunteers. FIELD STRENGTH: 1.5T. ASSESSMENT: All subjects underwent IVIM-DWI of the kidneys, and image analysis was performed by two radiologists. The mean values of true diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) were acquired from renal parenchyma. Correlation between IVIM-DWI parameters and estimated glomerular filtration rate (eGFR), as well as pathological damage, were assessed. STATISTICAL TESTS: One-way analysis of variance (ANOVA), paired sample t-test and Spearman correlation analysis. RESULTS: The paired sample t-test revealed that IVIM-DWI parameters were significantly lower in medulla than cortex for both patients and controls (P < 0.01). Regardless of whether eGFR was reduced, ANOVA revealed that f values of renal parenchyma were significantly lower in patients than controls (P < 0.05). Spearman correlation analysis revealed that there were positive correlations between eGFR and D (cortex, r = 0.466, P < 0.001; medulla, r = 0.491, P < 0.001), and between eGFR and f (cortex, r = 0.713, P < 0.001; medulla, r = 0.512, P < 0.001). Negative correlations were found between f and glomerular injury (cortex, r = -0.773, P < 0.001; medulla, r = -0.629, P < 0.001), and between f and tubulointerstitial lesion (cortex, r = -0.728, P < 0.001; medulla, r = -0.547, P < 0.001). DATA CONCLUSION: IVIM-DWI might be feasible for noninvasive evaluation of renal function and pathology of CKD, especially in detection of renal insufficiency at an early stage. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1251-1259.

Staging liver fibrosis with DWI: is there an added value for diffusion kurtosis imaging?

OBJECTIVES: To assess liver fibrosis in patients with chronic liver disease using diffusion kurtosis imaging (DKI) in comparison with conventional diffusion-weighted imaging, with histology as reference standard. METHODS: This prospective study included 81 patients and DKI with b-values of 0, 200, 500, 1,000, 1,500, 2,000 s/mm2 were performed. Mean diffusivity (MD), mean kurtosis (MK) and apparent diffusion coefficient (ADC) maps were calculated. The diagnostic efficacy of MD, MK and ADC for predicting stage 2 fibrosis or greater, and stage 3 fibrosis or greater were compared. RESULTS: The MD (rho=-0.491, p<0.001), MK (rho=0.537, p<0.001) and ADC (rho=-0.496, p<0.001) correlated significantly with fibrosis stages, and ADC exhibited a strong negative correlation with MK (rho=-0.968; p<0.001) and a moderate association with MD (rho=0.601, p<0.001). Areas under the curves (AUCs) for predicting stage 2 fibrosis or greater were not significantly different (p>0.05) between MK (0.809) and ADC (0.797) as well as between MD (0.715) and ADC. AUCs were also similar for MD (0.710), MK (0.768) and ADC (0.747) for predicting stage 3 fibrosis or greater. CONCLUSION: Although DKI is feasible for predicting liver fibrosis in patients with chronic liver disease, MD and MK offer similar diagnostic performance to ADC values. KEY POINTS: • Diffusion kurtosis imaging is feasible for staging liver fibrosis. • Diffusion kurtosis and monoexponential model are highly correlated. • The kurtosis model offers no added value to the conventional, monoexponential model.

ADCtotal ratio and D ratio derived from intravoxel incoherent motion early after TACE are independent predictors for survival in hepatocellular carcinoma.

PURPOSE: To explore the threshold of intravoxel incoherent motion (IVIM) parameters, apparent diffusion coefficient [ADCtotal and ADC(0,500) ] ratios 24-48 hours after transarterial chemoembolization (TACE) to assess early response in patients with unresectable hepatocellular carcinoma (HCC) and to compare the association between diffusion-weighted imaging with the intravoxel incoherent motion (IVIM-DWI) and mRECIST with survival. MATERIALS AND METHODS: Institutional Review Board approval and informed consent were obtained for this prospective study. There were 30 patients undergoing 1.5T magnetic resonance imaging (MRI) with IVIM-DWI of 12 b values (0, 10, 20, 30, 40, 50, 70, 100, 200, 300, 500, 800 s/mm2 ) 1 week before and 24-48 hours after TACE. Response was assessed with the change of true diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (PF), ADCtotal , and ADC(0,500) values relative to baseline and with mRECIST. Receiver operating characteristic (ROC) curve analysis was used to explore the threshold of these parameters ratios. Kaplan-Meier, log-rank tests, and the Cox hazard model were used to correlate the response variables with progression-free survival (PFS) and to assess the incidence and potential clinical risk factors for PFS. Mann-Whitney U-test was used to compare the difference in parameters between different groups with progression within and beyond median PFS prior to TACE. RESULTS: Median PFS was 99 days, within which 16 patients progressed. The threshold of ADCtotal ratio, D ratio, and ADC(0,500) ratio were 13.1% (P = 0.001), 7.0% (P = 0.011), and 3.6% (P = 0.018) with sensitivity and specificity of 78.6% and 87.5%, 85.7% and 62.5%, 78.6% and 75%, respectively. The predictive utility of ADCtotal ratio, D ratio, and ADC(0,500) ratio for PFS were 0.848, 0.772, and 0.754, respectively. Survival analyses showed ADCtotal ratio, D ratio, ADC(0,500) ratio, liver cirrhosis, and mRECIST had a significant effect on PFS (P < 0.05). ADCtotal ratio and D ratio were independent predictors for 99-day PFS (P = 0.025, P = 0.036). There were no significant differences in pretreatment IVIM-DWI parameters between PFS > 99-day group and PFS ≤ 99-day group with P values of 0.547 for D, 0.394 for D*, 0.575 for PF, 0.901 for ADC(0,500) , and 0.506 for ADCtotal , respectively. CONCLUSION: The ADCtotal ratio and D ratio 24-48 hours after TACE were independent predictors for response to TACE for HCC, and showed stronger association with PFS than mRECIST. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:820-830.

Staging liver fibrosis in chronic hepatitis B with T1 relaxation time index on gadoxetic acid-enhanced MRI: Comparison with aspartate aminotransferase-to-platelet ratio index and FIB-4.

PURPOSE: To assess the accuracy of the T1 relaxation time index on gadoxetic acid-enhanced magnetic resonance imaging (MRI) for staging liver fibrosis in chronic hepatitis B (CHB), in comparison and combination with the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4). MATERIALS AND METHODS: A retrospective study of gadoxetic acid-enhanced T1 mapping and serum biochemical tests was performed on 126 CHB patients who underwent gadoxetic acid-enhanced 1.5T MRI, and the histological score used as the gold standard. The reduction rate of T1 relaxation time before and 20 minutes after gadoxetic acid injection (ΔT1 , ΔR1%), the contrast uptake rate (KHep ), APRI, and FIB-4 were calculated. The diagnostic efficacy of ΔT1 , ΔR1%, KHep , APRI, and FIB-4 for predicting stage 2 or greater (≥S2), stage 3 or greater (≥S3), and stage 4 (S4) was compared. RESULTS: ΔT1 (r = -0.513, P < 0.001), ΔR1% (r = -0.626, P < 0.001), KHep (r = -0.527, P < 0.001), APRI (r = 0.519, P < 0.001), and FIB-4 (r = 0.476, P < 0.001) correlated significantly with fibrosis stages. Areas under the curves (AUCs) of ΔR1% for detecting ≥S2, ≥S3, and S4 were 0.849, 0.827, and 0.809, which were greater than that of APRI (0.763, 0.745, 0.787) and FIB-4 (0.727, 0.738, 0.772), but significant difference was found only in discriminating ≥S2 between ΔR1% and FIB-4 (P = 0.027). The combination of all five indices performed best, with AUC, sensitivity, and specificity of 0.860, 87.21%, and 72.50% for diagnosing ≥S2, 0.878, 82.81%, and 85.48% for ≥S3, and 0.867, 80.00%, and 83.95% for S4. CONCLUSION: The gadoxetic acid-enhanced T1 relaxation time index appears to be superior to APRI and FIB-4 for predicting hepatic fibrosis. The combined use of gadoxetic acid-enhanced T1 mapping, APRI, and FIB-4 may be more reliable for staging liver fibrosis in CHB. LEVEL OF EVIDENCE: 4 J. Magn. Reson. Imaging 2017;45:1186-1194.

Role of MR in the differentiation of IgG4-related from non-IgG4-related hepatic inflammatory pseudotumor.

BACKGROUND: Hepatic inflammatory pseudotumor (IPT) is classified into 2 types based on IgG4 stain: IgG4-related and non-IgG4-related; the two types differ not only in their pathological characteristics, but also in the clinical features. This study aimed to investigate the MR character of hepatic IPT, and differentiate the IgG4-related IPT from the non-IgG4-related IPT. METHODS: Twenty-five patients with 27 histologically proven hepatic IPTs were retrospectively analyzed. Ten lesions were diagnosed as IgG4-related IPT, and the other 17 as non-IgG4-related IPT. The MR signal features on T1, T2-weighted, dynamic-enhanced, and diffusion-weighted imaging were evaluated and compared. RESULTS: The dominant lesions were subcapsularly distributed (n=17, 63.0%) with clear boundary (n=20, 74.1%), and showed progressive enhancement pattern (n=21, 77.8%) with diffuse homogeneous (n=12, 44.4%) or heterogeneous (n=8, 29.6%) hyperintensity, accompanied by delayed capsule-like enhancement (n=17, 63.0%) and central nonenhanced areas (n=18, 66.7%). Morphological features (P>0.05) were not sufficient to differentiate IgG4-related IPT from non-IgG4-related IPT; the wash-out pattern was only found in 2 IgG4-related IPT, while the progressive enhancement pattern was more common in the non-IgG4-related lesions (n=16) (P=0.022). During portal and delayed phases, iso-/hypoenhanced lesions were only seen in 3 IgG4-related IPT, and circular-enhanced lesions (n=5) existed exceptionally in the non-IgG4-related group with significant differences (P=0.029 and 0.027). Most IgG4-related IPTs had lower apparent diffusion coefficient compared with the liver parenchyma (n=6), while most non-IgG4-related IPTs had higher apparent diffusion coefficient value (n=13) (P=0.046). CONCLUSIONS: Although MR images of hepatic IPT have certain characteristics, they are not enough to differentiate IgG4-related IPT from non-IgG4-related IPT. The enhancement pattern, signal features on portal and delayed phases, and the apparent diffusion coefficient value of the lesion may be helpful for the diagnosis.

Comparison of the effect of region-of-interest methods using gadoxetic acid-enhanced MR imaging with diffusion-weighted imaging on staging hepatic fibrosis.

OBJECTIVE: To evaluate the utility of T1 mapping on gadoxetic acid-enhanced MRI and DWI for staging liver fibrosis and assess the influence of ROI positioning on interobserver variability, T1 relaxation time and ADC value. METHODS: This retrospective study was approved by the institutional review board and included 150 patients (mean age 58 years old; 91 men and 59 women). Liver fibrosis stages (S) were histopathologically determined. T1 relaxation time and ADC value of liver were measured by three distinct ROI protocols (the whole left lobe liver, the whole right lobe liver and the individual ROIs). T1 relaxation time measurements were compared with ADC values according to S scores. Interobserver variability for the T1 relaxation times and ADC values by the three distinct ROI protocols was analyzed by calculating the ICC. RESULTS: T1 relaxation time measurements by the three distinct ROI protocols on severe fibrosis stage were significantly higher than the relative values on mild fibrosis stage. The mean ADC values on severe fibrosis stage showed no significantly different when measured by means of the whole right lobe liver (p = 0.057) and the individual ROIs (p = 0.10), compared with the relative values on mild fibrosis stage. AUCs of T1 relaxation time and ADC value by the means of the three distinct ROI protocols were 0.614, 0.676, 0.677 and 0.656, 0.585, 0.575 for identification of severe fibrosis stage. The interobserver reproducibility was excellent for measuring the right lobe liver T1 relaxation time and the individual ROIs T1 relaxation time (ICC 0.814, 0.883, respectively). CONCLUSIONS: T1 relaxation time measurements by means of the three distinct ROI protocols on gadoxetic acid-enhanced MR imaging were a potential biomarker in staging of hepatic fibrosis, which were more accuracy than DWI-ADC measurements. The more reproducible results were obtained when measuring T1 relaxation time of the whole right lobe liver and the individual ROIs.

Assessing liver function in patients with HBV-related HCC: a comparison of T1 mapping on Gd-EOB-DTPA-enhanced MR imaging with DWI.

OBJECTIVES: To compare the potential of T1 mapping on gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) for assessing liver function in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). METHODS: One hundred consecutive patients with known HBV-related HCCs were included. T1 relaxation time and apparent diffusion coefficient (ADC) of the liver were measured, and the reduction rate of T1 relaxation time (∆%) was calculated. T1 relaxation time measurements were compared with ADC values according to the Model for End-Stage Liver Disease (MELD) score. RESULTS: Hepatobiliary phase (HBP) and ∆% of T1 relaxation time measurements showed significant correlations with MELD score (rho = 0.571, p < 0.0001; rho = -0.573, p < 0.0001, respectively). HBP and ∆% of T1 relaxation time were significantly different between good (MELD ≤8) and poor liver function (MELD ≥9) (p < 0.0001 for both). Areas under the receiver operating characteristic curves (AUCs) of T1 relaxation time for HBP (AUC 0.84) and ∆% (AUC 0.82) were significantly better than for ADC (AUC 0.53; p < 0.0001). CONCLUSIONS: T1 mapping on Gd-EOB-DTPA-enhanced MRI showed promise for evaluating liver function in patients with HBV-related HCC, while DWI was not reliable. HBP T1 relaxation time measurement was equally accurate as ∆% measurement. KEY POINTS: • T 1 mapping on Gd-EOB-DTPA MRI was accurate for assessing liver function. • HBP T 1 relaxation time measurement was as accurate as ∆% T 1 • T 1 mapping on Gd-EOB-DTPA MRI was more accurate than DWI-ADC measurement.

Intrahepatic distant recurrence following complete radiofrequency ablation of small hepatocellular carcinoma: risk factors and early MRI evaluation.

BACKGROUND: Radiofrequency ablation (RFA) is related to a high intrahepatic distant recurrence (IDR) rate, and the associations between IDR and relevant imaging features have not yet been fully investigated. This study aimed to determine both clinical and imaging risk factors of IDR after complete RFA for HBV-related small hepatocellular carcinoma (HCC) (≤ 3 cm). METHODS: Thirty-five patients (29 men and 6 women; mean age 60.7 years) with 40 HBV-related small HCCs who underwent complete RFA were included in our study. The incidence and potential clinical and MR imaging risk factors for IDR after RFA were assessed using the Kaplan-Meier method, the log-rank test and a stepwise Cox hazard model. RESULTS: The median follow-up period was 25 (4-45) months, and IDR was observed in 20 (57.1%) patients. The 12- and 24-month cumulative IDR-free survival rates were 76.7% and 61.3%, respectively. Univariate analysis revealed that pretreatment albumin < 3.5 g/dL (P = 0.026), multinodular tumor (P = 0.032), ablative margin < 3 mm (P = 0.007), no or disrupted periablational enhancement within 24 hours (P = 0.001) and at 1 month (P = 0.043) after RFA, and hyperintensity of the central ablative zone on T1-weighted images (T1WI) at 1 month after RFA (P = 0.004) were related to IDR. Multivariate analysis showed that pretreatment albumin < 3.5 g/dL (P = 0.032), multinodular tumor (P = 0.012), no or disrupted periablational enhancement within 24 hours after RFA (P = 0.001), and hyperintensity of the central ablative zone on T1WI at 1 month after RFA (P = 0.003) were independent risk factors for IDR. During the 1-month follow-up, the apparent diffusion coefficient exhibited an up-and-down evolution without significant value in the prediction of IDR following RFA. CONCLUSIONS: Patients with HBV-related small HCC had a high IDR rate after RFA. The risk factors included low serum albumin, multiple nodules, lesions with no or disrupted periablational enhancement and persistent hyperintensity in the central ablative zone on T1WI within 1 month after RFA.

MR imaging of primary hepatic neuroendocrine neoplasm and metastatic hepatic neuroendocrine neoplasm: a comparative study.

PURPOSE: To investigate MR characteristics in differentiating primary hepatic neuroendocrine neoplasm (PHNEN) from metastatic hepatic neuroendocrine neoplasm (MHNEN). MATERIALS AND METHODS: Thirty-nine patients with histopathologically proven liver neuroendocrine neoplasm were retrospectively analyzed. The morphological and MR signal features on T1, T2-weighted, dynamic-enhanced, and diffusion-weighted imaging were evaluated and compared between the PHNEN group (n = 12) and the MHNEN group (n = 27). RESULTS: The tumor size (P = 0.0084), number (P = 0.017), distribution (P = 0.000), contour (P = 0.041), the presence of capsule-like enhancement (P = 0.034), tumor homogeneity (P = 0.018) and the apparent diffusion coefficient (ADC) values (P = 0.024) were different between PHNENs and MHNENs. Large, solitary or massive-growing nodules with lobulated or irregular contour, capsule-like enhancement, heterogeneous signals or lower ADC values supported the diagnosis of PHNEN compared with MHNEN. ROC analysis demonstrated an area under the curve of 0.746, when the optimal cutoff value of 1.049 × 10(-3) mm(2)/s was used, a sensitivity of 63.0 % (95 % CI, 44.2-79.4 %), a specitivity of 80.0 % (95 % CI, 50.1-96.4 %), a positive predictive value of 89.5 % (95 % CI, 70.9-98.2 %), and a negative predictive value of 44.4 % (95 % CI, 23.4-67.0 %) can be achieved. CONCLUSIONS: MRI may provide valuable information for the diagnosis and differential diagnosis of PHNENs and MHNENs.