Effect of decreased contrast injection flow rate on aortic enhancement in 80-KV peak CT with contrast dose reduction.

BACKGROUND: Effect of decreased injection flow rate of contrast agent at the same iodine dose and delivery rate on aortic enhancement has not been clearly elucidated. PURPOSE: To evaluate the effect of decreased injection flow rate of contrast agent on aortic peak enhancement in a dynamic flow phantom and on aortic enhancement in clinical dynamic 80-kVp computed tomography (CT) with contrast dose reduction. MATERIAL AND METHODS: In the dynamic flow phantom experiment, the effect of a decreased injection flow rate at the same total iodine dose and delivery rate on simulated aortic peak enhancement was evaluated. In the clinical retrospective study, we searched 312 patients with renal dysfunction who underwent an 80-kVp abdominal dynamic CT with 40% reduction of contrast agent from a standard 120-kVp protocol and measured the aortic enhancement at the level of the hepatic hilum. Independent predictors for aortic enhancement were determined by multiple linear regression analysis, and after adjustment of significant predictors, independent variables for acquiring optimal aortic enhancement, ≥300 HU, were determined by multiple logistic regression analysis. RESULTS: In the phantom experiment, decreased flow rate showed a significant but small descent effect (6%-9%) on simulated aortic peak enhancement. In the multiple linear regression analysis, only age was an independent predictor of aortic enhancement; there was no independent predictor for optimal age-adjusted aortic enhancement of ≥300 HU. CONCLUSIONS: Decreased injection flow rate had a small influence on aortic enhancement in vitro but had no significant effect on the aortic enhancement in clinical dynamic 80-kVp CT.

Effect of Diameter and Number of Hepatocellular Carcinomas on Survival After Resection, Transarterial Chemoembolization, and Ablation.

INTRODUCTION: Most studies predicting survival after resection, transarterial chemoembolization (TACE), and ablation analyzed diameter and number of hepatocellular carcinomas (HCCs) as dichotomous variables, resulting in an underestimation of risk variation. We aimed to develop and validate a new prognostic model for patients with HCC using largest diameter and number of HCCs as continuous variables. METHODS: The prognostic model was developed using data from patients undergoing resection, TACE, and ablation in 645 Japanese institutions. The model results were shown after balanced using the inverse probability of treatment-weighted analysis and were externally validated in an international multi-institution cohort. RESULTS: Of 77,268 patients, 43,904 patients, including 15,313 (34.9%) undergoing liver resection, 13,375 (30.5%) undergoing TACE, and 15,216 (34.7%) undergoing ablation, met the inclusion criteria. Our model (http://www.u-tokyo-hbp-transplant-surgery.jp/about/calculation.html) showed that the 5-year overall survival (OS) in patients with HCC undergoing these procedures decreased with progressive incremental increases in diameter and number of HCCs. For patients undergoing resection, the inverse probability of treatment-weighted-adjusted 5-year OS probabilities were 10%-20% higher compared with patients undergoing TACE for 1-6 HCC lesions <10 cm and were also 10%-20% higher compared with patients undergoing ablation when the HCC diameter was 2-3 cm. For patients undergoing resection and TACE, the model performed well in the external cohort. DISCUSSION: Our novel prognostic model performed well in predicting OS after resection and TACE for HCC and demonstrated that resection may have a survival benefit over TACE and ablation based on the diameter and number of HCCs.

Effect of Ultra High-Resolution Computed Tomography and Model-Based Iterative Reconstruction on Detectability of Simulated Submillimeter Artery.

OBJECTIVE: To evaluate the effect of ultra high-resolution computed tomography (UHRCT) and model-based iterative reconstruction (MBIR) on the detectability of simulated submillimeter artery. METHODS: A small vessel phantom ranging from 0.4 to 2.0 mm in diameter and edge phantoms of low to high attenuation values were scanned by UHRCT (super-high-resolution mode and normal-resolution-mode) and conventional CT, and data were reconstructed by MBIR and filtered back projection (FBP). Vessel detectability was assessed subjectively and the effective size at which 50% of response was achieved (ES50 [mm]) was calculated. Modulation transfer function (MTF) was calculated by an edge spread function method. RESULTS: ES50 of super high-resolution mode (0.36 mm for MBIR and 0.50 mm for FBP) was significantly smaller than those of normal-resolution mode (P < 0.01). In the MTF analysis, the MTF of MBIR improved as the edge phantom attenuation increased, whereas that of FBP was stable. CONCLUSIONS: Both UHRCT and MBIR are effective for the detectability of simulated submillimeter artery.

Analysis of electropharmacological effects of AVE0118 on the atria of chronic atrioventricular block dogs: characterization of anti-atrial fibrillatory action by atrial repolarization-delaying agent.

AVE0118, an inhibitor of IKur, Ito and IK,ACh, was in the drug pipeline for atrial fibrillation. To investigate the limitation of AVE0118 as an anti-atrial fibrillatory drug, we studied its electropharmacological effects particularly focusing on the anti-atrial fibrillatory action as reverse translational research. We adopted the chronic atrioventricular block beagle dogs (n = 4), having a pathophysiology of bradycardia-associated, volume overload-induced chronic heart failure, in which the atrial fibrillation was induced by 10 s of burst pacing on atrial septum. AVE0118 in doses of 0.24 and 1.2 mg/kg, i.v. over 10 min hardly altered electrophysiological variables. Meanwhile, AVE0118 in a dose of 6 mg/kg, i.v. over 10 min delayed the inter-atrial conduction in a frequency-dependent manner and prolonged the atrial effective refractory period in a reverse frequency-dependent manner, whereas it did not significantly alter the duration of atrial fibrillation or its cycle length. The increment of atrial effective refractory period was 3.3 times greater compared with that of ventricular one at a basic cycle length of 400 ms. Torsade de pointes was not induced during the experimental period. Thus, AVE0118 may possess a favorable cardiac safety pharmacological profile, but its weak anti-atrial fibrillatory effect would indicate the limitation of atrial repolarization-delaying agents for suppressing atrial fibrillation.

Magnetic resonance elastography is as accurate as liver biopsy for liver fibrosis staging.

BACKGROUND: Liver MR elastography (MRE) is available for the noninvasive assessment of liver fibrosis; however, no previous studies have compared the diagnostic ability of MRE with that of liver biopsy. PURPOSE: To compare the diagnostic accuracy of liver fibrosis staging between MRE-based methods and liver biopsy using the resected liver specimens as the reference standard. STUDY TYPE: A retrospective study at a single institution. POPULATION: In all, 200 patients who underwent preoperative MRE and subsequent surgical liver resection were included in this study. Data from 80 patients were used to estimate cutoff and distributions of liver stiffness values measured by MRE for each liver fibrosis stage (F0-F4, METAVIR system). In the remaining 120 patients, liver biopsy specimens were obtained from the resected liver tissues using a standard biopsy needle. FIELD STRENGTH/SEQUENCE: 2D liver MRE with gradient-echo based sequence on a 1.5 or 3T scanner was used. ASSESSMENT: Two radiologists independently measured the liver stiffness value on MRE and two types of MRE-based methods (threshold and Bayesian prediction method) were applied. Two pathologists evaluated all biopsy samples independently to stage liver fibrosis. Surgically resected whole tissue specimens were used as the reference standard. STATISTICAL TESTS: The accuracy for liver fibrosis staging was compared between liver biopsy and MRE-based methods with a modified McNemar's test. RESULTS: Accurate fibrosis staging was achieved in 53.3% (64/120) and 59.1% (71/120) of patients using MRE with threshold and Bayesian methods, respectively, and in 51.6% (62/120) with liver biopsy. Accuracies of MRE-based methods for diagnoses of ≥F2 (90-91% [108-9/120]), ≥F3 (79-81% [95-97/120]), and F4 (82-85% [98-102/120]) were statistically equivalent to those of liver biopsy (≥F2, 79% [95/120], P ≤ 0.01; ≥F3, 88% [105/120], P ≤ 0.006; and F4, 82% [99/120], P ≤ 0.017). DATA CONCLUSION: MRE can be an alternative to liver biopsy for fibrosis staging. LEVEL OF EVIDENCE: 3. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1268-1275.

Comparison of diagnostic accuracies of two- and three-dimensional MR elastography of the liver.

PURPOSE: To evaluate the effect of imaging sequence (spin-echo echo-planar imaging [EPI] and gradient-echo [GRE]) and postprocessing method (two-dimensional [2D] and 3D inversion algorithms) on liver MR elastography (MRE) and to validate the diagnostic performance of EPI-MRE3D versus conventional GRE-MRE2D for liver fibrosis staging. MATERIALS AND METHODS: Three MRE methods (EPI-MRE3D , EPI-MRE2D , and GRE-MRE2D ) were performed on soft and mildly stiff phantoms and 58 patients with chronic liver disease using a 3 Tesla clinical MRI scanner, and stiffness values were compared among the three methods. A validation study comprised 73 patients with histological liver fibrosis (F0-4, METAVIR system). Areas under the receiver operating characteristic curves (AUCs) and accuracies for diagnosing significant fibrosis (F3-4) and cirrhosis (F4) were compared between EPI-MRE3D and GRE-MRE2D . RESULTS: Stiffness values of the soft and mildly stiff phantoms were 2.4 kPa and 4.0 kPa by EPI-MRE3D ; 2.6 kPa and 4.2 kPa by EPI-MRE2D ; and 2.7 kPa and 4.2 kPa by GRE-MRE2D . In patients, EPI-MRE3D provided significantly lower stiffness values than other methods (P < 0.001). However, there was no significant difference between GRE-MRE2D and EPI-MRE2D (P = 0.12). The AUCs and accuracies of EPI-MRE3D and GRE-MRE2D were statistically equivalent in the diagnoses of significant fibrosis (F3-4) and cirrhosis (F4) (all P < 0.005). CONCLUSION: EPI-MRE3D showed modestly lower liver stiffness values than conventional GRE-MRE2D . The diagnostic performances of EPI-MRE3D and GRE-MRE2D were equivalent for liver fibrosis staging. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1163-1170.

Outcome of hypovascular hepatic nodules with positive uptake of gadoxetic acid in patients with cirrhosis.

OBJECTIVES: To evaluate the longitudinal risk to patients with cirrhosis of hypervascular hepatocellular carcinoma (HCC) developing from hypovascular hepatic nodules that show positive uptake of gadoxetic acid (hyperintensity) on hepatocyte phase images. METHODS: In 69 patients, we evaluated findings from serial follow-up examinations of 633 hepatic nodules that appeared hypovascular and hyperintense on initial gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) until the nodules demonstrated hypervascularity and were diagnosed as hypervascular HCC. Cox analyses were performed to identify risk factors for the development of hypervascular HCCs from the nodules. RESULTS: The median follow-up was 663 days (range, 110 to 1215 days). Hypervascular HCCs developed in six of the 633 nodules (0.9 %) in five of the 69 patients. The only independent risk factor, the nodule's initial maximum diameter of 10 mm or larger, demonstrated a hazard ratio of 1.25. The one-year risk of hypervascular HCC developing from a nodule was 0.44 %. The risk was significantly higher for nodules of larger diameter (1.31 %) than those smaller than 10 mm (0.10 %, p < 0.01). CONCLUSIONS: Hypervascular HCC rarely develops from hypovascular, hyperintense hepatic nodules. We observed low risk even for nodules of 10 mm and larger diameter at initial examination. KEY POINTS: • Hypervascularization was rare on follow-up examination of hypovascular, hyperintense nodules • The risk of hypervascularization in a nodule increased with large size • Hypovascular, hyperintense nodules require neither treatment nor more intense follow-up.

Gadoxetic acid disodium-enhanced MR imaging of cholangiolocellular carcinoma of the liver: imaging characteristics and histopathological correlations.

OBJECTIVES: To review the gadoxetic acid disodium (EOB)-enhanced magnetic resonance (MR) imaging features of cholangiolocellular carcinoma (CoCC) of the liver and compare them with those of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). METHODS: EOB-enhanced MR images of 19 patients with CoCC, 23 with ICC, and 51 with HCC were retrospectively evaluated qualitatively and quantitatively. Univariate and multivariate analyses were performed to determine the characteristic MR features of CoCC with histopathological-imaging correlation. RESULTS: Multivariate logistic regression analysis showed that dot-/band-shaped internal enhancement during the arterial and portal phases (P < 0.001), and larger arterial ring enhancement ratio (CoCC, 0.13 ± 0.04; ICC, 0.074 ± 0.04; P = 0.013) were significantly independently associated with CoCC in contrast to ICC, whereas several MR features including progressive enhancement during the portal and late phases (P < 0.001), target appearance in the hepatocyte phase (P = 0.004), and vessel penetration (P = 0.013) were significantly more frequently associated with CoCC than HCC. The dot-/band-like internal enhancement (78.9% of CoCCs) histopathologically corresponded to the tumour cell nest with vascular proliferations and retained Glisson's sheath structure. CONCLUSIONS: EOB-enhanced MR features of CoCC largely differ from those of HCC but are similar to those of ICC. However, the finding of thicker arterial ring enhancement with dot-/band-like internal enhancement could help differentiate CoCC from ICC. KEY POINTS: • Gadoxetic acid-enhanced MR features of cholangiolocellular carcinoma (CoCC) resembled those of intrahepatic cholangiocarcinoma (ICC). • Gadoxetic acid-enhanced MR features of CoCC largely differed from those of hepatocellular carcinoma. • Dot-/band-like internal enhancement of CoCC may be helpful for differentiating from ICC. • Arterial ring enhancement of CoCC was larger than that of ICC.

Morphophenotypic changes in human multistep hepatocarcinogenesis with translational implications.

BACKGROUND & AIMS: Human hepatocarcinogenesis in cirrhosis is thought to be multistep and characterized by a spectrum of nodular lesions, ranging from low to high grade dysplastic nodules (LGDN and HGDN) to early and progressed hepatocellular carcinoma (eHCC and pHCC). The aim of this study was to investigate the morphophenotypical changes of this sequence and their potential translational significance. METHODS: We scored the vascular profile, ductular reaction/stromal invasion and overexpression of five biomarkers (GPC3, HSP70, GS, CHC, and EZH2), in a series of 100 resected nodules (13 LGDN, 16 HGDN, 42 eHCC and 29 small pHCC). RESULTS: The score separated the four groups of nodules as individual entities (p<0.01). In the sequence, biomarker's overexpression progressively increased with parallel decrease of ductular reaction; the vascular remodeling started very early (LGDN) but did not further develop in a proportion of HCC. eHCC was the most heterogeneous entity, with marginal overlap with HGDN and pHCC. Liver environment (fibrosis, etiology) did not impact on the phenotype of the different nodules. A subclass of eHCC (16/42) without evidence of stromal invasion was identified, suggesting a "preinvasive stage" (p<0.05). For diagnosis, the application of four and five biomarkers (rather than the usual three) improved the sensitivity of the assay for the detection of eHCC (76% and 93% vs. 52%); biomarkers in alternative combinations, and also increased the sensitivity of the assay (GS+CHC+EZH2: 76%; GS+CHC+EZH2+HSP70: 90%). CONCLUSIONS: This study supports the multistep nature of human hepatocarcinogenesis, and suggests that eHCC is more heterogeneous than previously thought. This provides further information of the potential translational significance into clinical practice.

The Optimal Body Size Index with Which to Determine Iodine Dose for Hepatic Dynamic CT: A Prospective Multicenter Study.

PURPOSE: To identify the body size parameter that exhibits the best correlation with aortic and hepatic enhancement at hepatic dynamic computed tomography (CT) in a large patient population enrolled in a multicenter study. MATERIALS AND METHODS: This prospective study was approved by the ethics committee of each of the 31 participating institutions where 1342 patients were enrolled between April 2012 and September 2013. All patients provided either written or oral informed consent. All patients underwent hepatic dynamic CT, which included preenhanced, hepatic arterial phase (HAP), and portal venous phase (PVP) scanning, performed with the routine scanning protocol of each institution. Changes in CT number (in Hounsfield units) per gram of iodine in the aorta (eA/I) and liver (eL/I) during HAP and PVP scanning were recorded for each patient. Hierarchical multivariate linear regression analysis was performed in which the outcome variable was either eA/I or eL/I; the independent variables were age, sex, one body size parameter (height, body weight, body mass index, lean body weight [LBW], or body surface area), and liver function (aspartate aminotransferase, albumin, and total bilirubin levels). A two-level hierarchical model in which patients were level 1 and the institution was level 2 was used. RESULTS: Hierarchical multivariate linear regression analysis revealed that in the population not stratified by sex, body size was significantly correlated with eA/I and eL/I (P < .001) and that LBW exhibited the strongest correlation with eA/I and eL/I (r = -0.561 and r = -0.601, respectively). Sex-stratified analysis showed that LBW was more strongly correlated with eA/I and eL/I in women (r = -0.779 and r = -0.948, respectively) than in men (r = -0.500 and r = -0.494, respectively) or in the nonstratified total population. CONCLUSION: Among body size parameters, LBW exhibited the strongest correlation with aortic and hepatic enhancement, especially in women.

Biochemical and Clinical Predictive Approach and Time Point Analysis of Hepatobiliary Phase Liver Enhancement on Gd-EOB-DTPA-enhanced MR Images: A Multicenter Study.

Purpose To identify biochemical factors associated with liver enhancement over time on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images and predict the optimal time point of the hepatobiliary phase in various clinical settings. Materials and Methods This study was approved by the institutional review boards, and written informed consent was obtained from the 1903 patients enrolled. Simple and multiple logistic regression analyses were performed to investigate the biochemical factors associated with liver-to-spleen contrast (LSC) of at least 1.5 in the hepatobiliary phase. Changes in LSC and lesion-to-liver contrast (LLC) of lesions over time (at 5, 10, 15, and 20 minutes) were investigated with a linear mixed-effects model in patients and lesions. For LSC, the optimal cutoff value was determined with receiver operating characteristic analysis of the most significant variable. Differences in LSC and LLC were analyzed in various clinical settings. Results Ultimately, 1870 patients were evaluated, as 33 were excluded according to study criteria. Prothrombin (PT) activity, total bilirubin level (P = .020), and total cholesterol level (P = .005) were significantly associated with LSC of at least 1.5 at 20 minutes, and PT activity was identified as the most significant factor (odds ratio, 1.271; 95% confidence interval: 1.109, 1.455; P = .001). LSC of at least 1.5 at 20 minutes with PT activity of at least 86.9% and less than 86.9% occurred in 555 of 626 patients (88.6%) and 388 of 575 patients (67.5%), respectively. Satisfactory liver enhancement at 20 minutes was significantly more likely to be achieved by patients with hepatitis B virus than by those with hepatitis C virus (P < .001) and by patients with metastasis than by those with hepatocellular carcinoma (P < .001). No significant difference in LLC was observed in patients examined at 1.5 and 3.0 T (P = .133). Conclusion Hepatic enhancement is significantly associated with PT activity, total bilirubin level, and total cholesterol level. PT activity of at least 86.9% could be used to shorten examination times at Gd-EOB-DTPA-enhanced MR imaging. © RSNA, 2016 Online supplemental material is available for this article.

Usefulness of MR elastography for detecting clinical progression of cirrhosis from child-pugh class A to B in patients with type C viral hepatitis.

PURPOSE: To evaluate the usefulness of magnetic resonance elastography (MRE) in detecting the clinical progression of cirrhosis from Child-Pugh class A to B in patients with hepatitis C. MATERIALS AND METHODS: We reviewed the data of 101 consecutive patients with type C viral hepatitis and clinically suspected cirrhosis who fulfilled the all following criteria: available MRE at 1.5 Tesla (T) or 3.0T and laboratory tests within a month, Child-Pugh class A, platelet count less than 155 × 10(3) /µL, no clinical history of hepatocellular carcinoma, and ≥6 months of follow-up after MRE. We longitudinally analyzed the incidence of cirrhosis progression as defined by the clinical progression from Child-Pugh class A to B at two subsequent follow-up points. Risk of cirrhosis progression was assessed by Cox analyses and Kaplan-Meyer methods. RESULTS: Cirrhosis progression was noted in 25 patients during the follow-up period. Liver stiffness (hazard ratio [HR] by 1 kPa increase = 1.397; P = 0.0074), Child-Pugh score of 6 versus score 5 (HR of 3.085; P = 0.0276), and treatment responses to anti-viral therapy versus nonresponse (HR of <0.001, P = 0.0006) were independent risk factors of cirrhosis progression. The 1-year risk (0.7%; 95% confidence interval, 0.1-4.2%) of cirrhosis progression was negligible in patients with liver stiffness of <3.3 kPa or response to anti-viral treatment. CONCLUSION: MRE is useful to stratify the risk of cirrhosis progression in patients with hepatitis C. J. Magn. Reson. Imaging 2016;44:715-722.

Acute Adverse Reactions to Nonionic Iodinated Contrast Media for CT: Prospective Randomized Evaluation of the Effects of Dehydration, Oral Rehydration, and Patient Risk Factors.

OBJECTIVE: The objective of our study was to determine the effects of dehydration and oral rehydration on the incidence of acute adverse reactions to iodinated contrast media administered during abdominal and pelvic CT in outpatients. SUBJECTS AND METHODS: For our prospective randomized study performed at a single institution, adult outpatients undergoing contrast-enhanced abdominal CT were randomly divided into a rehydration group (n = 2244 patients [1379 men and 865 women]; mean age, 65.2 years; age range, 18-90 years) and a control group (n = 3715 [2112 male patients and 1603 female patients]; mean age, 65.8 years; age range, 17-96 years), which included an age- and sex-matched subgroup (adjusted control group, n = 2244). The rehydration group received an oral rehydration solution (500 mL of liquid in which osmotic pressure is adjusted to enhance gastrointestinal absorption) before abdominal and pelvic CT. Patients were also divided into subclinically dehydrated (n = 997) and hydrated (n = 4962) groups according to their answers to a questionnaire that they completed before the CT examination. The patients were interviewed about contrast-induced adverse reactions before they left the CT room, and the reactions were categorized as allergiclike or physiologic. The incidence of reactions was compared between the rehydration and control groups and between the subclinical dehydration and hydrated groups. The rehydration and control groups were compared with an unpaired t test or a chi-square or Fisher test. RESULTS: The overall incidence of an acute adverse reaction was 4.3% (254/5959); the acute adverse reactions included 136 allergiclike and 118 physiologic reactions. Fourteen allergiclike and nine physiologic reactions were moderate grade, and none was severe. There was no significant difference between the rehydration group and adjusted control group in the overall incidence of adverse reactions (99/2244 [4.4%] vs 100/2244 [4.5%], respectively; p = 0.9422) or between the subclinically dehydrated group and hydrated group in the incidence of allergiclike reactions (25/997 [2.5%] vs 111/4962 [2.2%], p = 0.6062) and physiologic reactions (22/997 [2.2%] vs 96/4962 [1.9%], p = 0.5793). Younger age was a risk factor for both allergiclike and physiologic reactions (p ≤ 0.0019). CONCLUSION: Dehydration and oral rehydration did not affect the incidence of acute adverse reactions to iodinated contrast material for abdominal and pelvic CT in our randomized prospective trial.

Association of splenic MR elastographic findings with gastroesophageal varices in patients with chronic liver disease.

PURPOSE: To identify magnetic resonance imaging (MRI)-based parameters associated with gastroesophageal varices (GEVs) in patients with chronic liver disease. MATERIALS AND METHODS: Ninety-three patients were divided into three groups based on endoscopic findings: group 1 with no GEVs (n = 49), group 2 with mild GEVs (n = 30), and group 3 with severe GEVs (n = 14). We used a multivariate logistic regression analysis to assess liver stiffness, aspartate aminotransferase-to-platelet ratio index, spleen stiffness and volume, portal vein velocity, cross-sectional area, and flow volumes potential independent associators of any (mild and severe) GEVs or severe GEVs. RESULTS: The analysis showed that spleen and liver stiffness and spleen volume were independently associated with any GEVs (spleen stiffness, odds ratio [95% confidence interval], 1.25 [1.04-1.68], P = 0.018; liver stiffness, 1.52 [1.13-2.17], P = 0.006; spleen volume, 1.01 [1.00-1.01], P = 0.016), whereas spleen stiffness was associated with severe GEVs (1.82 [1.25-2.95]; P = 0.005). CONCLUSION: Liver and spleen stiffness and spleen volume are associated with GEVs in patients with chronic liver disease. Compared with liver stiffness and spleen volume, spleen stiffness is more strongly associated with severe GEVs.

MRI-based staging of hepatic fibrosis: Comparison of intravoxel incoherent motion diffusion-weighted imaging with magnetic resonance elastography.

PURPOSE: To evaluate the use of intravoxel incoherent motion (IVIM) imaging for staging hepatic fibrosis, and compare its staging ability with that of magnetic resonance elastography (MRE). MATERIALS AND METHODS: This study included 129 patients with pathologically staged liver fibrosis, and 53 patients with healthy livers. All patients underwent both MRE and IVIM imaging. Four diffusivity indices were calculated with 11 b-values; slow diffusion coefficient related to molecular diffusion (D), fast diffusion coefficient related to perfusion in micro-vessels (D*), perfusion-related diffusion fraction (f), and apparent diffusion coefficient (ADC). Receiver operating characteristic curve analysis was performed to determine the accuracy of IVIM imaging and MRE for staging hepatic fibrosis. RESULTS: D*, f, and ADC values decreased significantly with fibrosis stage (P < 0.0124), and liver stiffness increased (P < 0.0001). The Az value of MRE was significantly higher than that of D* for all fibrosis stages (D* vs. MRE for ≥ F1, 0.851 vs. 0.992 [P < 0.0001]; ≥ F2, 0.898 vs. 0.998 [P = 0.0003]; ≥ F3, 0.904 vs. 0.995 [P = 0.0004]; F4, 0.885 vs. 0.996 [P < 0.0001]). CONCLUSION: IVIM imaging is a useful technique for evaluating hepatic fibrosis, but MRE is better able to discriminate fibrosis stages than IVIM imaging.

Hepatitis activity should be considered a confounder of liver stiffness measured with MR elastography.

PURPOSE: To evaluate the effect of hepatitis activity on liver stiffness measurements and the role of serum alanine aminotransferase (ALT) in liver fibrosis staging by MR elastography (MRE). MATERIALS AND METHODS: We measured liver stiffness (kPa) in 135 patients by MRE and histologically assessed fibrosis and hepatitis activity within 2 months. Stepwise multiple linear regression was performed to determine the maximum adjusted R(2) against liver stiffness, after adjusting for nothing (model 1), ALT/upper limit of normal categories (model 2), and hepatitis activity (A grade) by METAVIR (model 3). Logistic regression was used to identify independent factors associated with pathologically proven cirrhosis. RESULTS: Platelet count and METAVIR F score were strongly associated with liver stiffness. The adjusted R(2) value of model 3 (0.7026) was higher than those of models 1 (0.6472) and 2 (0.6564), showing that hepatitis activity affected liver stiffness measurement. High ALT levels (odds ratio, 0.0066; P = 0.0003) as well as MRE (odds ratio, 9.91; P < 0.0001) were independently associated with cirrhosis. CONCLUSION: Hepatitis activity may be a confounder of liver stiffness measurement during liver fibrosis staging using MRE. MRE can potentially make an overdiagnosis of liver cirrhosis if the patient has high ALT levels.

Whole-body total lesion glycolysis measured on fluorodeoxyglucose positron emission tomography/computed tomography as a prognostic variable in metastatic breast cancer.

BACKGROUND: In this retrospective study, the authors evaluated the prognostic value of whole-body total lesion glycolysis (WTLG) on FDG/PET images in metastatic breast cancer (MBC) patients. METHODS: We retrospectively evaluated 54 MBC patients who were diagnosed as having one or more metastatic lesions between June 2005 and March 2013. Twenty-four patients were diagnosed at the initial presentation (group A) and 30 patients were diagnosed for the first time at some point after a surgery (group B). Patients were excluded if they had received chemotherapy within 30 days before PET/CT. SUVmax and total TLG were calculated for all lesions in each patient and the highest SUVmax and the whole-body TLG (WTLG) values were used as independent variables for the analyses. Mean ages and the proportions of histopathological subtypes were compared between two groups using Mann-Whitney U test and Fisher's exact test, respectively. The prognostic significance of PET parameters was assessed using Cox proportional hazards regression analysis. RESULTS: For groups A and B, the median follow-up period was 26 months (range, 3-58 months) and 40.5 months (range, 3-69 months), and the median age was 61 years (range, 42-81 years) and 59 years (range, 24-74 years), respectively. There were no significant differences between two groups in age (p = 0.294) or histopathological subtype (p = 0.384). In the univariate analyses, WTLG was found to be significantly associated with overall survival (OS) for patients of group A (p = 0.012). In the multivariate analysis, WTLG was also significantly associated with OS (p = 0.015). Only hormonal receptor level was a significant indicator of longer OS in patients with recurrent MBC (group B). CONCLUSIONS: This study demonstrated that WTLG on PET/CT is an independent prognostic factor for survival in breast cancer patients with metastases at the initial presentation.

Presence of a hypovascular hepatic nodule showing hypointensity on hepatocyte-phase image is a risk factor for hypervascular hepatocellular carcinoma.

PURPOSE: To determine whether the presence of a hypovascular nodule in the liver showing hypointensity on hepatocyte-phase of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) is a risk factor for hypervascular hepatocellular carcinoma (HCC) in patients with chronic liver disease. MATERIALS AND METHODS: Forty-one patients with pathologically confirmed hypervascular HCC and 41 age- and gender-matched controls were retrospectively selected. These patients had undergone EOB-MRI at least twice: the latest EOB-MRI and EOB-MRI performed more than 6 months earlier. History of hypervascular HCC, presence of a hypointense hypovascular nodule in previous hepatocyte-phase MR images, percent prothrombin time, platelet count, serum levels of albumin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, α-fetoprotein, and protein induced by vitamin K absence-II (PIVKA-II) were variables evaluated by multivariate logistic regression analysis. RESULTS: Multivariate analysis revealed that serum albumin level (odds ratio [95% confidence interval], 0.19 [0.06-0.57]; P = 0.0024), history of hypervascular HCC (8.62 [2.71-32.8]; P = 0.0001), and presence of a hypointense hypovascular nodule (4.18 [1.18-17.2]; P = 0.0256) were significant risk factors for hypervascular HCC. CONCLUSION: Patients with chronic liver disease showing a hypointense hypovascular nodule in the liver on hepatocyte-phase EOB-MRI have a high risk of HCC development.

Hepatocellular carcinoma risk assessment using gadoxetic acid-enhanced hepatocyte phase magnetic resonance imaging.

AIM: To investigate whether the patients with hypovascular liver nodules determined on the arterial phase and hypointensity on the hepatocyte phase gadoxetic acid-enhanced magnetic resonance imaging (hypovascular hypointense nodules) are at increased risk of hepatocarcinogenesis, we assessed subsequent typical hepatocellular carcinoma (HCC) development at any sites of the liver with and without such nodules. METHODS: One hundred and twenty-seven patients with chronic hepatitis B or C and without a history of HCC, including 68 with liver cirrhosis, were divided into those with (non-clean liver group, n = 18) and without (clean liver group, n = 109) hypovascular hypointense nodules. All the patients were followed up for 3 years, and HCC development rates and risk factors were analyzed with the Kaplan-Meier method and the Cox proportional hazard model, respectively. RESULTS: A total of 17 patients (10 in the non-clean liver group and seven in the clean liver group) developed typical HCC. Cumulative 3-year rates of HCC development were 55.5% in the non-clean liver group and 6.4% in the clean liver group (P < 0.001), and those at the different sites from the initial nodules was also higher in the non-clean liver group (22.2%) than the clean liver group (6.4%) (P = 0.003). Multivariate analysis identified older age (P = 0.024), low platelet counts (P = 0.017) and a non-clean liver (P < 0.001) as independent risk factors for subsequent HCC development. CONCLUSION: Patients with hypovascular hypointense liver nodules are at a higher risk for HCC development at any sites of the liver than those without such nodules.

Computed tomography (CT) venography with dual-energy CT: low tube voltage and dose reduction of contrast medium for detection of deep vein thrombosis.

OBJECTIVES: To assess whether low-dose contrast medium and low-tube voltage computed tomography (CT) venography can be used for clinical diagnosis. METHODS: This prospective study included 63 patients who were randomized into 3 groups and administered contrast medium of either 600, 500, or 400 mg of iodine per kilogram (mgI/kg). All patients underwent dual-energy CT at either 80 or 135 kilovolt (peak) (kV[p]). Control images (120 kV[p]) were acquired from them and were compared with 80-kV(p) images. The mean CT values of the bilateral femoral and popliteal veins were compared. RESULTS: The mean CT values of the 80-kV(p) images were significantly higher than 120-kV(p) images for all doses. No significant difference was observed for the CT values of the 80-kV(p) images with the 400-mgI/kg dose and the control images (600 mgI/kg at 120 kV[p]). CONCLUSIONS: Low tube voltage enabled a reduction of contrast medium to 400 mgI/kg for CT venography.