Accessory liver lobe: an uncommon abdominal mass mimicker.

Heterotopic hepatic tissue is a rare development anomaly, exhibiting diverse forms and locations. We present a case report of an asymptomatic woman in her 40s who had an 8 cm mass in the left hypochondrium detected on routine ultrasound, which was initially suspected to be a tumour. Further investigation revealed that the mass had a similar enhancement to the liver on gadoxetate disodium-enhanced MRI and presented a connection with the original liver via vascular pedicle, favouring the diagnosis of accessory liver lobe (ALL). Accurate differentiation of ALL from other abdominal masses poses a diagnostic challenge, potentially leading to misdiagnosis of malignant tumours and unnecessary interventions. Although usually small and asymptomatic, rarely they can present with acute complications, and cross-sectional techniques play an important role in enabling early diagnosis and management. Therefore, radiologists must raise awareness regarding ALL, their imagological findings, and diagnostic pathways, and understand potential associated complications.

Targeted opening of the blood-brain barrier using VCAM-1 functionalised microbubbles and "whole brain" ultrasound.

Metastatic tumours in the brain now represent one of the leading causes of death from cancer. Current treatments are largely ineffective owing to the combination of late diagnosis and poor delivery of therapies across the blood-brain barrier (BBB). Conjugating magnetic resonance imaging (MRI) contrast agents with a monoclonal antibody for VCAM-1 (anti-VCAM1) has been shown to enable detection of micrometastases, two to three orders of magnitude smaller in volume than those currently detectable clinically. The aim of this study was to exploit this targeting approach to enable localised and temporary BBB opening at the site of early-stage metastases using functionalised microbubbles and ultrasound. Methods: Microbubbles functionalised with anti-VCAM1 were synthesised and shown to bind to VCAM-1-expressing cells in vitro. Experiments were then conducted in vivo in a unilateral breast cancer brain metastasis mouse model using Gadolinium-DTPA (Gd-DTPA) enhanced MRI to detect BBB opening. Following injection of Gd-DTPA and targeted microbubbles, the whole brain volume was simultaneously exposed to ultrasound (0.5 MHz, 10% duty cycle, 0.7 MPa peak negative pressure, 2 min treatment time). T1-weighted MRI was then performed to identify BBB opening, followed by histological confirmation via immunoglobulin G (IgG) immunohistochemistry. Results: In mice treated with targeted microbubbles and ultrasound, statistically significantly greater extravasation of Gd-DTPA and IgG was observed in the left tumour-bearing hemisphere compared to the right hemisphere 5 min after treatment. No acute adverse effects were observed. There was no investigation of longer term bioeffects owing to the nature of the study. Conclusion: The results demonstrate the feasibility of using targeted microbubbles in combination with low intensity ultrasound to localise opening of the BBB to metastatic sites in the brain. This approach has potential application in the treatment of metastatic tumours whose location cannot be established a priori with conventional imaging methods.

Lobe-Based Hepatic Uptake Index of Gd-EOB-DTPA on Contrast-Enhanced MRI to Quantitatively Discriminate between Compensated and Decompensated Hepatitis B-Related Cirrhosis.

Purpose: To use hepatic uptake index (HUI) of liver lobes on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) to discriminate between patients with hepatitis B-related cirrhosis in compensated and decompensated statuses. Methods: Forty-four consecutive patients with hepatitis B-related cirrhosis who underwent Gd-EOB-DTPA-enhanced MRI were divided into compensated and decompensated statuses based on clinical evaluation. Volume and signal intensity of individual lobes were retrospectively measured to calculate HUI of the right liver lobe (RHUI), medial (MHUI) and lateral (LHUI) left liver lobes, and caudate lobe (CHUI). Spearman's rank correlation analyses were performed to evaluate relationships of lobe-based HUI with Child-Pugh and model for end-stage liver disease (MELD) scoring system scores in compensated and decompensated statuses. The Mann-Whitney U-test was used to compare the lobe-based HUI between compensated and decompensated statuses. The performance of lobe-based HUI in distinguishing cirrhosis was evaluated using receiver operating characteristic (ROC) analysis, and the area under the ROC curve (AUC) was calculated as a measure of accuracy. Delong's method was used for statistical analysis to elucidate which HUI is optimal. Results: Compensated and decompensated liver cirrhosis were confirmed in 25 (56.82%) and 19 (43.18%) patients, respectively. According to Spearman's rank correlation analysis, RHUI, MHUI, LHUI, and CHUI were all significantly associated with Child-Pugh and MELD scores (all P values <0.05). Receiver operating characteristic analysis demonstrated that among all lobe-based HUI parameters, RHUI could best perform the previous discrimination with a cut-off of 485.73 and obtain an AUC of 0.867. The AUC of RHUI improved and was significantly different from that of MHUI, LHUI, and CHUI (P = 0.03, P = 0.007, and P < 0.001, respectively, Delong's test). Conclusions: The RHUI could help quantitatively discriminate hepatitis B-related cirrhosis between compensated and decompensated statuses.

PET/CT-Based Absorbed Dose Maps in 90Y Selective Internal Radiation Therapy Correlate with Spatial Changes in Liver Function Derived from Dynamic MRI.

Functional liver parenchyma can be damaged from treatment of liver malignancies with 90Y selective internal radiation therapy (SIRT). Evaluating functional parenchymal changes and developing an absorbed dose (AD)-toxicity model can assist the clinical management of patients receiving SIRT. We aimed to determine whether there is a correlation between 90Y PET AD voxel maps and spatial changes in the nontumoral liver (NTL) function derived from dynamic gadoxetic acid-enhanced MRI before and after SIRT. Methods: Dynamic gadoxetic acid-enhanced MRI scans were acquired before and after treatment for 11 patients undergoing 90Y SIRT. Gadoxetic acid uptake rate (k1) maps that directly quantify spatial liver parenchymal function were generated from MRI data. Voxel-based AD maps, derived from the 90Y PET/CT scans, were binned according to AD. Pre- and post-SIRT k1 maps were coregistered to the AD map. Absolute and percentage k1 loss in each bin was calculated as a measure of loss of liver function, and Spearman correlation coefficients between k1 loss and AD were evaluated for each patient. Average k1 loss over the patients was fit to a 3-parameter logistic function based on AD. Patients were further stratified into subgroups based on lesion type, baseline albumin-bilirubin scores and alanine transaminase levels, dose-volume effect, and number of SIRT treatments. Results: Significant positive correlations (ρ = 0.53-0.99, P < 0.001) between both absolute and percentage k1 loss and AD were observed in most patients (8/11). The average k1 loss over 9 patients also exhibited a significant strong correlation with AD (ρ ≥ 0.92, P < 0.001). The average percentage k1 loss of patients across AD bins was 28%, with a logistic function model demonstrating about a 25% k1 loss at about 100 Gy. Analysis between patient subgroups demonstrated that k1 loss was greater among patients with hepatocellular carcinoma, higher alanine transaminase levels, larger fractional volumes of NTL receiving an AD of 70 Gy or more, and sequential SIRT treatments. Conclusion: Novel application of multimodality imaging demonstrated a correlation between 90Y SIRT AD and spatial functional liver parenchymal degradation, indicating that a higher AD is associated with a larger loss of local hepatocyte function. With the developed response models, PET-derived AD maps can potentially be used prospectively to identify localized damage in liver and to enhance treatment strategies.

Comparison of the Ability of Gadobenate Dimeglumine and Gadolinium Ethoxybenzyl Dimeglumine to Display the major Features for Noninvasively Diagnosing Hepatocellular Carcinoma According to the LI-RADS 2018v.

OBJECTIVE: To compare the ability of gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA) and gadobenate dimeglumine (Gd-BOPTA) to display the 3 major features recommended by the Liver Imaging Reporting and Data System (LI-RADS 2018v) for diagnosing hepatocellular carcinoma (HCC). MATERIALS AND METHODS: In this retrospective study, we included 98 HCC lesions that were scanned with either Gd-EOB-DTPA-MR or Gd-BOPTA-M.For each lesion, we collected multiple variables, including size and enhancement pattern in the arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). The lesion-to-liver contrast (LLC) was measured and calculated for each phase and then compared between the 2 contrast agents. A P value < .05 was considered statistically significant. The display efficiency of the LLC between Gd-BOPTA and Gd-EOB-DTPA for HCC features was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: Between Gd-BOPTA and Gd-EOB-DTPA, significant differences were observed regarding the display efficiency for capsule enhancement and the LLC in the AP/PVP/DP (P < .05), but there was no significant difference regarding the LLC in the TP/HBP. Both Gd-BOPTA and Gd-EOB-DTPA had good display efficiency in each phase (AUCmin > 0.750). When conducting a total evaluation of the combined data across the 5 phases, the display efficiency was excellent (AUC > 0.950). CONCLUSION: Gd-BOPTA and Gd-EOB-DTPA are liver-specific contrast agents widely used in clinical practice. They have their own characteristics in displaying the 3 main signs of HCC. For accurate noninvasive diagnosis, the choice of agent should be made according to the specific situation.

Safety of Gadoxetate Disodium for Hepatobiliary MRI in Children and Adolescents.

Background Despite a proven role in the characterization of liver lesions, use of the gadolinium-based contrast agent (GBCA) gadoxetate disodium at MRI is limited in children due to a lack of comparative safety data. Purpose To evaluate the safety of the GBCA gadoxetate disodium (a linear ionic hepatobiliary contrast agent [HBA]) in children and adolescents, compared with extracellular contrast agents (ECA). Materials and Methods A retrospective analysis was conducted in children and adolescents aged 18 years or younger who underwent HBA-enhanced MRI at one of three tertiary hospitals from January 2010 to December 2022. The incidence of GBCA-associated acute adverse events was compared between MRI examinations with a HBA and those with ECA. Severity was categorized according to American College of Radiology guidelines (mild, moderate, or severe). (a) Propensity score matching using multivariable logistic regression models and (b) inverse probability of treatment weighting analysis based on nine covariates (age, sex, asthma, allergic rhinitis, chronic urticaria or atopy, food allergy, drug allergy, premedication, and history of GBCA-associated adverse events) were used for confounder adjustment. Results A total of 1629 MRI examinations (ECA, n = 1256; HBA, n = 373) in 1079 patients were included (mean age, 8.6 years ± 6.5; 566 girls). The per-examination incidence of GBCA-associated acute adverse events showed no evidence of a difference, with rates of 0.9% (11 of 1256 examinations) for ECA and 1.3% (five of 373 examinations) for HBA (odds ratio [OR], 1.55 [95% CI: 0.54, 4.46]; P = .42). Acute adverse events were all mild with ECA, whereas with HBA, they were mild for four patients and moderate for one patient. There was no evidence of a difference in the incidence of acute adverse events, even in propensity score matching (OR, 1.33 [95% CI: 0.30, 5.96]; P = .71) and inverse probability of treatment weighting analysis (OR, 0.84 [95% CI: 0.25, 2.86]; P = .78). Conclusion Gadoxetate disodium showed no difference in acute adverse events compared with ECA in children and adolescents, with further large-scale pediatric studies required to confirm its safety. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Otero in this issue.

Establishment of nomogram prediction model of contrast-enhanced ultrasound and Gd-EOB-DTPA-enhanced MRI for vessels encapsulating tumor clusters pattern of hepatocellular carcinoma.

To establish clinical prediction models of vessels encapsulating tumor clusters (VETC) pattern using preoperative contrast-enhanced ultrasound (CEUS) and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (EOB-MRI) in patients with hepatocellular carcinoma (HCC). A total of 111 resected HCC lesions from 101 patients were included. Preoperative imaging features of CEUS and EOB-MRI, postoperative recurrence, and survival information were collected from medical records. The best subset regression and multivariable Cox regression were used to select variables to establish the prediction model. The VETC-positive group had a statistically lower survival rate than the VETC-negative group. The selected variables were peritumoral enhancement in the arterial phase (AP), hepatobiliary phase (HBP) on EOB-MRI, intratumoral branching enhancement in the AP of CEUS, intratumoral hypoenhancement in the portal phase of CEUS, incomplete capsule, and tumor size. A nomogram was developed. High and low nomogram scores with a cutoff value of 168 points showed different recurrence-free survival rates and overall survival rates. The area under the curve (AUC) and accuracy were 0.804 and 0.820, respectively, indicating good discrimination. Decision curve analysis showed a good clinical net benefit (threshold probability > 5%), while the Hosmer-Lemeshow test yielded excellent calibration (P = 0.6759). The AUC of the nomogram model combining EOB-MRI and CEUS was higher than that of the models with EOB-MRI factors only (0.767) and CEUS factors only (0.7). The nomogram verified by bootstrapping showed AUC and calibration curves similar to those of the nomogram model. The Prediction model based on CEUS and EOB-MRI is effective for preoperative noninvasive diagnosis of VETC.

The Combination of Gd-EOB-DTPA Enhanced T1 Mapping with Apparent Diffusion Coefficient could Improve the Diagnostic Efficacy of Hepatocellular Carcinoma Grading.

BACKGROUND: Accurately predicting the hepatocellular carcinoma (HCC) grade may facilitate the rational selection of treatment strategies. The diagnostic efficacy of the combination of Gadolinium ethoxybenzy diethylenetriamine pentaacetic (Gd-EOB-DTPA) enhancement T1 mapping and apparent diffusion coefficient (ADC) values in predicting HCC grade needs further validation. OBJECTIVES: This study aimed to assess the capacity of Gd-EOB-DTPA-enhanced T1 mapping and ADC values, both individually and in combination, to discriminate between different grades of HCC. MATERIALS AND METHODS: From July 2017 to February 2020, 96 patients (male, 83; mean age, 53.67 years; age range, 29-71 years) clinically diagnosed with HCC were included in the present study. All patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI, including T1 mapping sequence) before surgery or biopsy. All the patients were categorized into 3 groups according to the pathological results (including 24 cases of well-differentiated HCCs, 59 cases of moderately differentiated HCCs, 13 cases of and poorly differentiated HCCs). The mean Gd-EOB-DTPA enhanced T1 values (ΔT1=[(T1pre-T1post)/T1pre]×100%) and ADC values between different grading groups of HCC were calculated and compared. The area under the characteristics curve (AUC), the diagnostic threshold, sensitivity, and specificity of ΔT1 and ADC for differential diagnosis were analyzed. RESULTS: Mean ΔT1 was 58% for well-differentiated HCCs, 50% for moderately-differentiated HCCs, and 43% for poorly-differentiated HCCs. ΔT1 showed statistical differences between the groups (P<0.001). The mean ADC values of the 3 groups were 1.11×10-3 mm2/s, 0.91×10-3 mm2/s, and 0.80×10-3mm2/s, respectively. ADC showed statistical differences between the groups (P<0.001). In discriminating well- differentiated group from the moderately differentiated group, the AUC of ΔT1 was 0.751 (95% CI: 0.642, 0.859), the AUC of ADC was 0.782 (95% CI: 0.671, 0.894), the AUC of combined model was 0.811 (95% CI: 0.709, 0.914). In discriminating the poorly differentiated group from the moderately differentiated group, the AUC of ΔT1 was 0.768 (95% CI: 0.634, 0.902), the AUC of ADC was 0.754 (95% CI: 0.603, 0.904), and the AUC of the combined model was 0.841 (95% CI: 0.729, 0.953). CONCLUSION: Gd-EOB-DTPA enhanced T1 mapping, and ADC values have complementary effects on the sensitivity and specificity for identifying different HCC grades. A combined model of Gd-EOB-DTPA-enhanced MRI T1 mapping and ADC values could improve diagnostic performance for predicting HCC grades.

Comparative analysis of the performance of hepatobiliary agents in depicting MRI features of microvascular infiltration in hepatocellular carcinoma.

OBJECTIVE: To compare the ability to depict MRI features of hepatobiliary agents in microvascular infiltration (MVI) of hepatocellular carcinoma (HCC) during different stages of dynamic enhancement MRI. MATERIALS AND METHODS: A retrospective study included 111 HCC lesions scanned with either Gd-EOB-DTPA or Gd-BOPTA. All cases underwent multiphase dynamic contrast-enhanced scanning before surgery, including arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). Two abdominal radiologists independently evaluated MRI features of MVI in HCC, such as peritumoral hyperenhancement, incomplete capsule, non-smooth tumor margins, and peritumoral hypointensity. Finally, the results were reviewed by the third senior abdominal radiologist. Chi-square (χ2) Inspection for comparison between groups. P < 0.05 is considered statistically significant. Receiver operating characteristic (ROC) curve was used to evaluate correlation with pathology, and the area under the curve (AUC) and 95% confidence interval (95% CI) were calculated. RESULTS: Among the four MVI evaluation signs, Gd-BOPTA showed significant differences in displaying two signs in the HBP (P < 0.05:0.000, 0.000), while Gd-EOB-DTPA exhibited significant differences in displaying all four signs (P < 0.05:0.005, 0.006, 0.000, 0.002). The results of the evaluations of the two contrast agents in the DP phase with incomplete capsulation showed the highest correlation with pathology (AUC: 0.843, 0.761). By combining the four MRI features, Gd-BOPTA and Gd-EOB-DTPA have correlated significantly with pathology, and Gd-BOPTA is better (AUC: 0.9312vs0.8712). CONCLUSION: The four features of hepatobiliary agent dynamic enhancement MRI demonstrate a good correlation with histopathological findings in the evaluation of MVI in HCC, and have certain clinical significance.

Uptake of gadolinium and dexamethasone in rat inner ear and facial nerve using different administrations.

BACKGROUND: The pathway by which drugs are injected subcutaneously behind the ear to act on the inner ear has not been fully elucidated. OBJECTIVES: To compare the uptake of gadopentetate dimeglumine (Gd-DTPA) and dexamethasone (Dex) in the cochlea and facial nerve of rats following different administrations. MATERIALS AND METHODS: Magnetic resonance imaging was applied to observe the distribution of Gd-DTPA in the facial nerve and inner ear. We observed the uptake of Dex after it was injected with different methods. RESULTS: Images of the intravenous (IV) and intramuscular (IM) groups showed that the bilateral cochlea of the rat was visualized almost simultaneously. While in the left post-auricular (PA) injection group, it was asynchronous. The maximum accumulation (Cmax) of the Gd in the left facial nerve of the PA group (35.406 ± 5.32) was substantially higher than that of the IV group (16.765 ± 3.7542) (p < .01). CONCLUSIONS: Compared with systemic administration, PA has the advantages of long Gd and Dex action time and high accumulation concentration to treat facial nerve diseases. SIGNIFICANCE: The distribution of Gd and Dex in the inner ear and facial nerve of rats following PA injection might be unique.

Value of Sonazoid-enhanced ultrasonography in characterizing indeterminate focal liver lesions on gadoxetic acid-enhanced liver MRI in patients without risk factors for hepatocellular carcinoma.

PURPOSE: To evaluate the added value of contrast-enhanced ultrasonography (CEUS) using Sonazoid in characterizing focal liver lesions (FLLs) with indeterminate findings on gadoxetic acid-enhanced liver MRI in patients without risk factors for hepatocellular carcinoma (HCC). METHODS: Patients who underwent CEUS using Sonazoid for characterizing indeterminate FLLs on gadoxetic acid-enhanced liver MRI were. The indeterminate FLLs were classified according to the degree of malignancy on a 5-point scale on MRI and combined MRI and CEUS. The final diagnosis was made either pathologically or based on more than one-year follow-up. The diagnostic performance was assessed using a receiver operating characteristic (ROC) curve analysis, and the net reclassification improvement (NRI) was calculated. RESULTS: A total of 97 patients (mean age, 49 years ± 16, 41 men, 80 benign and 17 malignant lesions) were included. When CEUS was added to MRI, the area under the ROC curve increased, but the difference was not statistically significant (0.87 [95% confidence interval {CI}, 0.77-0.98] for MRI vs 0.93 [95% CI, 0.87-0.99] for CEUS added to MRI, P = 0.296). The overall NRI was 0.473 (95% CI, 0.100-0.845; P = 0.013): 33.8% (27/80) of benign lesions and 41.2% (7/17) of malignant lesions were appropriately reclassified, whereas 10.0% (8/80) of benign lesions and 17.6% (3/17) of malignant lesions were incorrectly reclassified. CONCLUSIONS: Although performing CEUS with Sonazoid did not significantly improve the overall diagnostic performance in characterizing indeterminate FLLs on gadoxetic acid-enhanced liver MRI in patients without risk factors for HCC, it may increase radiologist's confidence in classifying FLLs.

Assessing teratogenic risks of gadolinium in freshwater environments: Implications for environmental health.

Gadolinium (Gd) is among the rare earth elements extensively utilized in both industrial and medical applications. The latter application appears to contribute to the rise in Gd levels in aquatic ecosystems, as it is excreted via urine from patients undergoing MRI scans and often not captured by wastewater treatment systems. The potential environmental and biological hazards posed by gadolinium exposure are still under investigation. This study aimed to assess the teratogenic risk posed by a gadolinium chelate on the freshwater cnidarian Hydra vulgaris. The experimental design evaluated the impact of pure Gadodiamide (25 µg/l, 50 µg/l, 100 µg/l, 500 µg/l) and its commercial counterpart compound (Omniscan®; 100 µg/l, 500 µg/l, 782.7 mg/l) at varying concentrations using the Teratogenic Risk Index (TRI). Here we showed a moderate risk (Class III of TRI) following exposure to both tested formulations at concentrations ≥ 100 µg/l. Given the potential for similar concentrations in aquatic environments, particularly near wastewater discharge points, a teratogenic risk assessment using the Hydra regeneration assay was conducted on environmental samples collected from three rivers (Tiber, Almone, and Sacco) in Central Italy. Additionally, chemical analysis of field samples was performed using ICP-MS. Analysis of freshwater samples revealed low Gd concentrations (≤ 0.1 µg/l), despite localized increases near domestic and/or industrial wastewater discharge sites. Although teratogenic risk in environmental samples ranged from high (Class IV of TRI) to negligible (Class I of TRI), the low Gd concentrations, particularly when compared to higher levels of other contaminants like arsenic and heavy metals, preclude establishing a direct cause-effect relationship between Gd and observed teratogenic risks in environmental samples. Nevertheless, the teratogenic risks observed in laboratory tests warrant further investigation.

Based on Gadolinium Ethoxybenzyl DTPA-Enhanced MRI: Diagnostic Performance of the Category-Modified LR-5 Criteria in Patients At Risk for Hepatocellular Carcinoma.

Introduction: We aimed to modify the LR-5 strategy to improve the diagnostic sensitivity for hepatocellular carcinoma (HCC) in high-risk patients while maintaining specificity. Methods: This study retrospectively analyzed 412 patients with 445 liver observations who underwent preoperative gadolinium ethoxybenzyl DTPA (GD-EOB-DTPA)-enhanced MRI followed by surgical procedures or biopsies. All observations were classified according to LI-RADS v2018, and the classifications were adjusted by modifying major features (MF)(substituting threshold growth with a more HCC-specific ancillary features (AF): presence of blood products within the mass, arterial phase hyperenhancement (APHE) was interpreted with hypointensity on precontrast imaging- isointensity in arterial phase (AP) and extending washout to transitional phase (TP)(2 min)). The specificity, sensitivity, and positive predictive value (PPV) were assessed to compare LR-5 (definitely HCC) diagnostic efficacy between LI-RADS version 2018 and modified LI-RADS. Results: Apart from nonenhancing "capsule", the interreader agreement of MFs and HCC-specific AFs between the two readers reached substantial or excellent ranges (κ values ranging from 0.631 to 0.911). According to LI-5 v2018, the specificity, sensitivity and PPV of HCC were 90.74%, 82.35%, and 98.17%, respectively. Based on a more HCC-specific AF, signal intensity in AP and TP (2 min), the sensitivity of the three modified strategies were 86.19%, 93.09%, 96.67% (P < .05)), while maintaining high specificity and PPV rates at 88.89% and 98.25% (P > .05) Conclusion: Further investigation into the efficacy of threshold growth as a MF is warranted. By utilizing GD-EOB-DTPA-enhanced MRI, enhancing the sensitivity of the modified LR-5 category may be achieved without compromising specificity and PPV in diagnosing HCC among high-risk patients.

Bone marrow lesions in knee osteoarthritis assessed by dynamic contrast-enhanced MRI with histopathological correlations.

BACKGROUND: Bone marrow lesions (BMLs) in knee osteoarthritis (OA) have been assessed histopathologically and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI); however, a direct comparison of the results has not been reported. PURPOSE: To evaluate and compare the findings by DCE-MRI and histopathology of subchondral BMLs in knee OA. MATERIAL AND METHODS: In total, 19 patients with medial tibiofemoral knee OA undergoing total knee arthroplasty were analyzed. Preoperative MRI, including a DCE sequence, was performed, and bone biopsies were obtained from the resected specimens corresponding to BML areas. The contrast enhancement by DCE-MRI was analyzed using semi-quantitative (area under the curve [AUC]), peak enhancement [PE]), and quantitative (Ktrans, Kep) methods. Enhancement in the medial OA compartment was compared with similar areas in a normal lateral compartment, and the DCE characteristics of BMLs were correlated with semi-quantitatively graded histopathological features. RESULTS: AUC and PE were significantly higher in medial tibial and femoral BMLs compared with the values in the lateral condyles; Ktrans and Kep were only significantly higher in the tibial plateau. In the tibia, AUC and PE were significantly correlated with the grade of vascular proliferation, and PE also with the degree of marrow fibrosis. There was no significant correlation between AUC/PE and histopathological findings in the femur and no correlation between quantitative DCE parameters and histopathological findings. CONCLUSION: BML characteristics by semi-quantitative DCE in the form of AUC and PE may be used as parameters for the degree of histopathological vascularization in the bone marrow whereas quantitative DCE data were less conclusive.

Comparison of the efficacy of the gadoxetic acid MRI-derived relative enhancement index (REI) and functional liver imaging score (FLIS) in predicting liver function: validation with Albumin-Bilirubin (ALBI) grade.

PURPOSE: This study compared the predictive performance of the relative enhancement index (REI) derived from gadoxetic acid (GA)-enhanced MRI with that of the functional liver imaging score (FLIS) in estimating liver function among patients with chronic liver disease (CLD) or liver cirrhosis (LC) by validating them with the albumin-bilirubin (ALBI) grade. MATERIALS AND METHODS: We retrospectively examined 166 patients (79 women, 87 men; 57.4 years) who were diagnosed with LC or CLD and underwent GA-enhanced MRI between August 2020 and September 2023. The enhancement ratio (ER) is calculated using the formula: ER = [hepatobiliary phase liver signal (SI HBP20)-precontrast liver signal (SI pre)]/SI pre. The REI is calculated using the formula: REI = Liver Volume (LV) × ER. FLIS was assigned from the sum of three HBP image features, each scored between 0 and 2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff values of ER, REI, and FLIS in differentiating between ALBI grades. The area under the curve (AUC), accuracy, sensitivity, and specificity were calculated for REI and FLIS to distinguish the ALBI grades. Spearman's rank correlation was used to evaluate the ER, REI, and FLIS correlations between the ALBI grades. To evaluate inter-reader reliability for LV, ER, REI, and FLIS, intraclass correlation coefficient (ICC) was used. RESULTS: ROC curve analysis showed that the optimal cutoff value of REI for predicting ALBI Grade 1 was 899-905 for readers 1 and 2 and 461-477 for ALBI Grade 3, respectively. REI performed best in predicting ALBI Grade 1, achieving an accuracy range of 94%-92.2%, sensitivity of 94.9%-94.1%, and specificity of 91.7%-87.5% for readers 1 and 2, respectively. All parameters showed high accuracy in distinguishing ALBI Grade 3 from other grades. However, REI outperformed the others, showing an accuracy range of 98.8%-97.6%, sensitivity of 94.4%-94.4%, and specificity of 99.3%-98% for readers 1 and 2, respectively. REI showed the best and very strong correlation with ALBI for both readers. CONCLUSION: REI showed a very strong correlation with the ALBI grades for assessing liver function. It outperformed FLIS in predicting the ALBI grades, indicating its potential as a radiologic tool comparable to or better than FLIS in predicting liver function, especially given its dependence on liver volume.

ISSLS prize in clinical/bioengineering science 2024: How standing and supine positions influence nutrient transport in human lumbar discs?-A serial post-contrast MRI study evaluating interplay between convection and diffusion.

PURPOSE: The intervertebral disc being avascular depends on diffusion and load-based convection for essential nutrient supply and waste removal. There are no reliable methods to simultaneously investigate them in humans under natural loads. For the first time, present study aims to investigate this by strategically employing positional MRI and post-contrast studies in three physiological positions: supine, standing and post-standing recovery. METHODS: A total of 100 healthy intervertebral discs from 20 volunteers were subjected to a serial post-contrast MR study after injecting 0.3 mmol/kg gadodiamide and T1-weighted MR images were obtained at 0, 2, 6, 12 and 24 h. At each time interval, images were obtained in three positions, i.e. supine, standing and post-standing recovery supine. The signal intensity values at endplate zone and nucleus pulposus were measured. Enhancement percentages were calculated and analysed comparing three positions. RESULTS: During unloaded supine position, there was slow gradual increase in enhancement reaching peak at 6 h. When the subjects assumed standing position, there was immediate loss of enhancement at nucleus pulposus which resulted in reciprocal increase in enhancement at endplate zone (washout phenomenon). Interestingly, when subjects assumed the post-standing recovery position, the nucleus pulposus regained the enhancement and endplate zone showed reciprocal loss (pumping-in phenomenon). CONCLUSIONS: For the first time, present study documented acute effects of physiological loading and unloading on nutrition of human discs in vivo. While during rest, solutes diffused gradually into disc, the diurnal short loading and unloading redistribute small solutes by convection. Standing caused rapid solute depletion but promptly regained by assuming resting supine position.

Gadolinium-based contrast agents aggravate mechanical and thermal hyperalgesia in a nitroglycerine-induced migraine model in male mice.

In the diagnosis of migraine, which is a neurovascular disease, gadolinium-based contrast agents (GBCAs) are used to rule out more serious conditions. On the other hand, it remains unclear as a scientific gap whether GBCAs may trigger migraine-related pain. The aim of this study was to investigate the effect of GBCAs on mechanical and thermal pain behaviour in a nitroglycerin (NTG)-induced migraine model in mice. NTG (10 mg/kg) was administered intraperitoneally to adult (6-8weeks old) BALB/c mice 2 h before behavioral tests 5 times every other day on days 1st, 3rd, 5th and 9th to induce migraine model (N = 50). As GBCAs, gadobenate dimeglumine (linear-ionic), Gadodiamide (linear-nonionic), and gadobutrol (macrocyclic-nonionic) were delivered intravenously through the tail vein of mice for 5 days on test days. Mechanical pain threshold (plantar and facial withdrawal threshold) was evaluated by plantar von Frey and periorbital von Frey tests on days 1st, 5th, and 9th, and thermal pain threshold (latency) was evaluated by hot plate and cold plate tests on days 3rd and 7th. There was a statistically significant increase in mechanical and thermal hyperalgesia in NTG administered groups compared to the control group. Gadodiamide, gadobutrol and gadobenate dimeglumine administration significantly decreased latency, paw and facial withdrawal threshold (0.18 ± 0.05, 0.17 ± 0.07, 0.16 ± 0.09; 9th day values respectively) compared to NTG group (0.27 ± 0.05). The results of this in vivo study show that GBCAs produce effects that may trigger migraine attacks in migraine. It is recommended that these effects be further investigated and supported by further clinical studies.

Deep learning-based compressed SENSE improved diffusion-weighted image quality and liver cancer detection: A prospective study.

PURPOSE: To assess whether diffusion-weighted imaging (DWI) with Compressed SENSE (CS) and deep learning (DL-CS-DWI) can improve image quality and lesion detection in patients at risk for hepatocellular carcinoma (HCC). METHODS: This single-center prospective study enrolled consecutive at-risk participants who underwent 3.0 T gadoxetate disodium-enhanced MRI. Conventional DWI was acquired using parallel imaging (PI) with SENSE (PI-DWI). In CS-DWI and DL-CS-DWI, CS but not PI with SENSE was used to accelerate the scan with 2.5 as the acceleration factor. Qualitative and quantitative image quality were independently assessed by two masked reviewers, and were compared using the Wilcoxon signed-rank test. The detection rates of clinically-relevant (LR-4/5/M based on the Liver Imaging Reporting and Data System v2018) liver lesions for each DWI sequence were independently evaluated by another two masked reviewers against their consensus assessments based on all available non-DWI sequences, and were compared by the McNemar test. RESULTS: 67 participants (median age, 58.0 years; 56 males) with 197 clinically-relevant liver lesions were enrolled. Among the three DWI sequences, DL-CS-DWI showed the best qualitative and quantitative image qualities (p range, <0.001-0.039). For clinically-relevant liver lesions, the detection rates (91.4%-93.4%) of DL-CS-DWI showed no difference with CS-DWI (87.3%-89.8%, p = 0.230-0.231) but were superior to PI-DWI (82.7%-85.8%, p = 0.015-0.025). For lesions located in the hepatic dome, DL-CS-DWI demonstrated the highest detection rates (94.8%-97.4% vs 76.9%-79.5% vs 64.1%-69.2%, p = 0.002-0.045) among the three DWI sequences. CONCLUSION: In patients at high-risk for HCC, DL-CS-DWI improved image quality and detection for clinically-relevant liver lesions, especially for the hepatic dome.

Comparison of Four Diagnostic Guidelines for Hepatocellular Carcinoma Using Gadoxetic Acid-enhanced Liver MRI.

Background Noninvasive diagnostic guidelines for hepatocellular carcinoma (HCC) vary across different global geographic areas, especially regarding criteria about gadoxetic acid-enhanced MRI. Purpose To compare the diagnostic performance of four different international HCC diagnosis guidelines and readers' judgment in diagnosing HCC using gadoxetic acid-enhanced MRI in patients at high risk for HCC. Materials and Methods This retrospective study included patients who had not undergone treatment, were at risk for HCC, and who underwent gadoxetic acid-enhanced MRI from January 2015 to June 2018 from 11 tertiary hospitals in South Korea. Four radiologists independently reviewed focal liver lesions (FLLs) according to four guidelines: American Association for the Study of Liver Diseases (AASLD)/Liver Imaging Reporting and Data System (LI-RADS), Korean Liver Cancer Association-National Cancer Center (KLCA-NCC), European Association for the Study of the Liver (EASL), and Asian Pacific Association for the Study of the Liver (APASL). Reader judgment (HCC or not HCC) was also recorded. Malignant FLLs were confirmed at pathology, and histologic and clinical follow-up data were used for benign FLLs. The guidelines' diagnostic performance was compared using generalized estimating equations. Additionally, the diagnostic odds ratio was assessed. Results A total of 2445 FLLs (median size, 27.4 mm) were analyzed in 2237 patients (mean age, 59 years ± 11 [SD]; 1666 male patients); 69.3% (1694 of 2445) were HCCs. KLCA-NCC showed the highest accuracy (80.0%; 95% CI: 78.7, 81.2; P = .001), with high sensitivity in Eastern guidelines (APASL, 89.1% [95% CI: 87.8, 90.3]; KLCA-NCC, 78.2% [95% CI: 76.6, 79.7]) and high specificity in Western guidelines (AASLD/LI-RADS, 89.6% [95% CI: 87.8, 91.2]; EASL, 88.1% [95% CI: 86.2, 89.9]) (P = .001). The diagnostic odds ratios were 20.7 (95% CI: 17.0, 25.3) for AASLD/LI-RADS, 18.9 (95% CI: 15.8, 22.6) for KLCA-NCC, 16.8 (95% CI: 13.8, 20.4) for EASL, and 8.9 (95% CI: 7.4, 10.7) for APASL. The readers' judgment demonstrated higher accuracy than that of the guidelines (accuracy, 86.0%; 95% CI: 84.9, 86.9; P = .001). Conclusion Among four different international HCC diagnosis guidelines, Eastern guidelines demonstrated higher sensitivity, whereas Western guidelines displayed higher specificity. KLCA-NCC achieved the highest accuracy, and AASLD/LI-RADS exhibited the highest diagnostic odds ratio. © RSNA, 2024 Supplemental material is available for this article.