MR Fingerprinting for Liver Tissue Characterization: A Histopathologic Correlation Study.

Background Liver MR fingerprinting (MRF) enables simultaneous quantification of T1, T2, T2*, and proton density fat fraction (PDFF) maps in single breath-hold acquisitions. Histopathologic correlation studies are desired for its clinical use. Purpose To compare liver MRF-derived metrics with separate reference quantitative MRI in participants with diffuse liver disease, evaluate scan-rescan repeatability of liver MRF, and validate MRF-derived measurements for histologic grading of liver biopsies. Materials and Methods This prospective study included participants with diffuse liver disease undergoing MRI from July 2021 to January 2022. Participants underwent two-dimensional single-section liver MRF and separate reference quantitative MRI. Linear regression, Bland-Altman plots, and coefficients of variation were used to assess the bias and repeatability of liver MRF measurements. For participants undergoing liver biopsy, the association between mapping and histologic grading was evaluated by using the Spearman correlation coefficient. Results Fifty-six participants (mean age, 59 years ± 15 [SD]; 32 women) were included to compare mapping techniques and 23 participants were evaluated with liver biopsy (mean age, 52.7 years ± 12.7; 14 women). The linearity of MRF with reference measurements in participants with diffuse liver disease (R2 value) for T1, T2, T2*, and PDFF maps was 0.86, 0.88, 0.54, and 0.99, respectively. The overall coefficients of variation for repeatability in the liver were 3.2%, 5.5%, 7.1%, and 4.6% for T1, T2, T2*, and PDFF maps, respectively. MRF-derived metrics showed high diagnostic performance in differentiating moderate or severe changes from mild or no changes (area under the receiver operating characteristic curve for fibrosis, inflammation, steatosis, and siderosis: 0.62 [95% CI: 0.52, 0.62], 0.92 [95% CI: 0.88, 0.92], 0.97 [95% CI: 0.96, 0.97], and 0.74 [95% CI: 0.57, 0.74], respectively). Conclusion Liver MR fingerprinting provided repeatable T1, T2, T2*, and proton density fat fraction maps in high agreement with reference quantitative mapping and may correlate with pathologic grades in participants with diffuse liver disease. © RSNA, 2022 Online supplemental material is available for this article.

Deep Learning-Driven Transformation: A Novel Approach for Mitigating Batch Effects in Diffusion MRI Beyond Traditional Harmonization.

BACKGROUND: "Batch effect" in MR images, due to vendor-specific features, MR machine generations, and imaging parameters, challenges image quality and hinders deep learning (DL) model generalizability. PURPOSE: We aim to develop a DL model using contrast adjustment and super-resolution to reduce diffusion-weighted images (DWIs) diversity across magnetic field strengths and imaging parameters. STUDY TYPE: Retrospective. SUBJECTS: The DL model was built using an open dataset from one individual. The MR machine identification model was trained and validated on a dataset of 1134 adults (54% females, 46% males), with 1050 subjects showing no DWI abnormalities and 84 with conditions like stroke and tumors. The 21,000 images were divided into 80% for training, 20% for validation, and 3500 for testing. FIELD STRENGTH/SEQUENCE: Seven MR scanners from four manufacturers with 1.5 T and 3 T magnetic field strengths. DWIs were acquired using spin-echo sequences and high-resolution T2WIs using the T2-SPACE sequence. ASSESSMENT: An experienced, board-certified radiologist evaluated the effectiveness of restoring high-resolution T2WI and harmonizing diverse DWI with metrics such as PSNR and SSIM, and the texture and frequency attributes were further analyzed using gray-level co-occurrence matrix and 1-dimensional power spectral density. The model's impact on machine-specific characteristics was gauged through the performance metrics of a ResNet-50 model. Comprehensive statistical tests were employed for statistical robustness, including McNemar's test and the Dice index. RESULTS: Our DL protocol reduced DWI contrast and resolution variation. ResNet-50 model's accuracy decreased from 0.9443 to 0.5786, precision from 0.9442 to 0.6494, recall from 0.9443 to 0.5786, and F1 score from 0.9438 to 0.5587. The t-SNE visualization indicated more consistent image features across multiple MR devices. Autoencoder halved learning iterations; Dice coefficient >0.74 confirmed signal reproducibility in 84 lesions. CONCLUSION: This study presents a DL strategy to mitigate batch effects in diffusion MR images, improving their quality and generalizability. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.

Feasibility of Quantitative MRI Using 3D-QALAS for Discriminating Immunohistochemical Status in Invasive Ductal Carcinoma of the Breast.

BACKGROUND: Two-dimensional synthetic MRI of the breast has limited spatial coverage. Three-dimensional (3D) synthetic MRI could provide volumetric quantitative parameters that may reflect the immunohistochemical (IHC) status in invasive ductal carcinoma (IDC) of the breast. PURPOSE: To evaluate the feasibility of 3D synthetic MRI using an interleaved Look-Locker acquisition sequence with a T2 preparation pulse (QALAS) for discriminating the IHC status, including hormone receptor (HR), human epidermal growth factor receptor 2 (HER 2), and Ki-67 expression in IDC. STUDY TYPE: Prospective observational study. POPULATION: A total of 33 females with IDC of the breast (mean, 52.3 years). FIELD STRENGTH/SEQUENCE: A 3-T, 3D-QALAS gradient-echo and fat-suppressed T1-weighted 3D fast spoiled gradient-echo sequences. ASSESSMENT: Two radiologists semiautomatically delineated 3D regions of interest (ROIs) of the whole tumors on the dynamic MRI that was registered to the synthetic T1-weighted images acquired from 3D-QALAS. The mean T1 and T2 were measured for each IDC. STATISTICAL TESTS: Intraclass correlation coefficient for assessing interobserver agreement. Mann-Whitney U test to determine the relationship between the mean T1 or T2 and the IHC status. Multivariate logistic regression analysis followed by receiver operating characteristics (ROC) analysis for discriminating IHC status. A P value <0.05 was considered statistically significant. RESULTS: The interobserver agreement was good to excellent. There was a significant difference in the mean T1 between HR-positive and HR-negative lesions, while the mean T2 value differed between HR-positive and HR-negative lesions, between the triple-negative and HR-positive or HER2-positive lesions, and between the Ki-67 level > 14% and ≤ 14%. Multivariate analysis showed that the mean T2 was higher in HR-negative IDC than in HR-positive IDC. ROC analysis revealed that the mean T2 was predictive for discriminating HR status, triple-negative status, and Ki-67 level. DATA CONCLUSION: 3D synthetic MRI using QALAS may be useful for discriminating IHC status in IDC of the breast. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: Stage 2.

A 1.4-million-year-old bone handaxe from Konso, Ethiopia, shows advanced tool technology in the early Acheulean.

In the past decade, the early Acheulean before 1 Mya has been a focus of active research. Acheulean lithic assemblages have been shown to extend back to ∼1.75 Mya, and considerable advances in core reduction technologies are seen by 1.5 to 1.4 Mya. Here we report a bifacially flaked bone fragment (maximum dimension ∼13 cm) of a hippopotamus femur from the ∼1.4 Mya sediments of the Konso Formation in southern Ethiopia. The large number of flake scars and their distribution pattern, together with the high frequency of cone fractures, indicate anthropogenic flaking into handaxe-like form. Use-wear analyses show quasi-continuous alternate microflake scars, wear polish, edge rounding, and striae patches along an ∼5-cm-long edge toward the handaxe tip. The striae run predominantly oblique to the edge, with some perpendicular, on both the cortical and inner faces. The combined evidence is consistent with the use of this bone artifact in longitudinal motions, such as in cutting and/or sawing. This bone handaxe is the oldest known extensively flaked example from the Early Pleistocene. Despite scarcity of well-shaped bone tools, its presence at Konso shows that sophisticated flaking was practiced by ∼1.4 Mya, not only on a range of lithic materials, but also occasionally on bone, thus expanding the documented technological repertoire of African Early Pleistocene Homo.

New geological and palaeontological age constraint for the gorilla-human lineage split.

The palaeobiological record of 12 million to 7 million years ago (Ma) is crucial to the elucidation of African ape and human origins, but few fossil assemblages of this period have been reported from sub-Saharan Africa. Since the 1970s, the Chorora Formation, Ethiopia, has been widely considered to contain ~10.5 million year (Myr) old mammalian fossils. More recently, Chororapithecus abyssinicus, a probable primitive member of the gorilla clade, was discovered from the formation. Here we report new field observations and geochemical, magnetostratigraphic and radioisotopic results that securely place the Chorora Formation sediments to between ~9 and ~7 Ma. The C. abyssinicus fossils are ~8.0 Myr old, forming a revised age constraint of the human-gorilla split. Other Chorora fossils range in age from ~8.5 to 7 Ma and comprise the first sub-Saharan mammalian assemblage that spans this period. These fossils suggest indigenous African evolution of multiple mammalian lineages/groups between 10 and 7 Ma, including a possible ancestral-descendent relationship between the ~9.8 Myr old Nakalipithecus nakayamai and C. abyssinicus. The new chronology and fossils suggest that faunal provinciality between eastern Africa and Eurasia had intensified by ~9 Ma, with decreased faunal interchange thereafter. The Chorora evidence supports the hypothesis of in situ African evolution of the Gorilla-Pan-human clade, and is concordant with the deeper divergence estimates of humans and great apes based on lower mutation rates of ~0.5 × 10(-9) per site per year (refs 13 - 15).

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.

Lithic technology, chronology, and marine shells from Wadi Aghar, southern Jordan, and Initial Upper Paleolithic behaviors in the southern inland Levant.

The Initial Upper Paleolithic (IUP) temporally overlaps with the range expansion of Homo sapiens populations in various parts of Eurasia and is often considered a key archaeological phase for investigating behavioral changes from the Middle Paleolithic. This paper reports upon new data from IUP occupations at Wadi Aghar, a rock shelter site in the southern Levant. In combining the results of radiometric dates and lithic analyses, we clarify the chronological and cultural position of Wadi Aghar assemblages in the Levantine IUP. As for the records about mobility, on-site activities, and resource procurement behaviors, we present analyses of lithic use-wear, tool-type composition, soil micromorphology, and marine shells. The lithic analyses and the optically stimulated luminescence (and subsidiary radiocarbon) dating of the Wadi Aghar materials suggest their chronocultural position in the IUP (45-40 ka for Layers C-D1; 39-36 ka for Layer B; possibly 50 ka for Layer D2), providing the southernmost location for the IUP in Eurasia. In the Levant, Wadi Aghar represents one of the few IUP sites in the inland areas. The results also indicate that the timing and technological sequences from the IUP to the following bladelet industries differed between the inland and coastal zones, likely reflecting geographically variable adaptive behaviors and/or cultural transmissions. One of the behavioral characteristics of IUP foragers at Wadi Aghar is the procurement of remote resources, represented by the transportation of marine shells from the Red Sea: Canarium fusiforme and Canarium cf. mutabile. Whether it was a direct procurement with increased mobility or a result of intergroup exchanges, it was not part of behavioral repertoires during the late MP in the same area. This can be understood as the expansion of resource procurement range, functioning as additional buffers from risk in the semiarid environments in the inland Levant.

Advanced maritime adaptation in the western Pacific coastal region extends back to 35,000-30,000 years before present.

Maritime adaptation was one of the essential factors that enabled modern humans to disperse all over the world. However, geographic distribution of early maritime technology during the Late Pleistocene remains unclear. At this time, the Indonesian Archipelago and eastern New Guinea stand as the sole, well-recognized area for secure Pleistocene evidence of repeated ocean crossings and advanced fishing technology. The incomplete archeological records also make it difficult to know whether modern humans could sustain their life on a resource-poor, small oceanic island for extended periods with Paleolithic technology. We here report evidence from a limestone cave site on Okinawa Island, Japan, of successive occupation that extends back to 35,000-30,000 y ago. Well-stratified strata at the Sakitari Cave site yielded a rich assemblage of seashell artifacts, including formally shaped tools, beads, and the world's oldest fishhooks. These are accompanied by seasonally exploited food residue. The persistent occupation on this relatively small, geographically isolated island, as well as the appearance of Paleolithic sites on nearby islands by 30,000 y ago, suggest wider distribution of successful maritime adaptations than previously recognized, spanning the lower to midlatitude areas in the western Pacific coastal region.

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.

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.

An Investigation of Transient Severe Motion Related to Gadoxetic Acid-enhanced MR Imaging.

PURPOSE: To investigate the cause of imaging artifacts observed during gadoxetic acid-enhanced arterial phase imaging of the liver. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board. Data were collected prospectively at two sites (site A, United States; site B, Japan) from patients undergoing contrast material-enhanced MR imaging with gadoxetic acid (site A, n = 154, dose = 0.05 mmol/kg; site B, n = 130, 0.025 mmol/kg) or gadobenate dimeglumine (only site A, n = 1666) from January 2014 to September 2014 at site A and from November 2014 to January 2015 at site B. Detailed comparisons between the two agents were made in the patients with dynamic liver acquisitions (n = 372) and age-, sex-, and baseline oxygen saturation (Spo2)-matched pairs (n = 130) at site A. Acquired data included self-reported dyspnea after contrast agent injection, Spo2, and breath-hold fidelity monitored with respiratory bellows. RESULTS: Self-reported dyspnea was more frequent with gadoxetic acid than with gadobenate dimeglumine (site A, 6.5% [10 of 154] vs 0.1% [two of 1666], P < .001; site B, 1.5% [two of 130]). In the matched-pair comparison, gadoxetic acid, as compared with gadobenate dimeglumine, had higher breath-hold failure rates (site A, 34.6% [45 of 130] vs 11.7% [15 of 130], P < .0001; site B, 16.2% [21 of 130]) and more severe artifacts during arterial phase imaging (site A, 7.7% [10 of 130] vs 0% [none of 130], P < .001; site B, 2.3% [three of 130]). Severe imaging artifacts in patients who received gadoxetic acid were significantly associated with male sex (P = .023), body mass index (P = .021), and breath-hold failure (P < .001) but not with dyspnea or Spo2 decrease. CONCLUSION: Severe motion-related artifacts in the arterial phase of gadoxetic acid-enhanced liver MR imaging are associated with breath-hold failure but not with subjective feelings of dyspnea or a substantial decrease in blood Spo2. Subjective feelings of dyspnea are not necessarily associated with imaging artifacts. The phenomenon, albeit at a lower rate, was confirmed at a second site in Japan.

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.

Hepatobiliary MR contrast agents in hypovascular hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) develops via multistep hepatocarcinogenesis, during which hypovascular/early HCC precedes the typical hypervascular HCC. The hypovascular HCC lacks the typical hallmark imaging features of HCC, such as late arterial phase enhancement and portal venous washout, limiting early detection using conventional extracellular contrast agents for dynamic magnetic resonance imaging (MRI) or computed tomography (CT) imaging. In recent years, gadolinium-based contrast agents with hepatobiliary uptake have garnered interest from radiologists and hepatologists due to their potential for improved detection of HCC during hepatobiliary phase MRI. Lesions with reduced or absent hepatocyte function appear hypointense in the hepatobiliary phase of gadoxetic acid-enhanced MRI. This behavior can be exploited for earlier detection of hypovascular HCC. This review describes the general characteristics and advantages of gadoxetic acid for the diagnosis of HCC with a particular focus on hypovascular/early HCC.

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.

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.