Search

Objectives: Patients with Crohn's disease (CD) require multiple assessments with magnetic resonance enterography (MRE) from a young age. Standard MRE protocols for CD include contrast-enhanced sequences. Gadolinium deposits in brain tissue suggest avoiding gadolinium could benefit patients with CD. This study aimed to compare the accuracy of the simplified Magnetic Resonance Index of Activity (sMaRIA) calculated with and without contrast-enhanced sequences in determining the response to biologic drugs in patients with CD., Methods: This post hoc analysis of a prospective study included patients with CD with endoscopic ulceration in ≥ 1 intestinal segment starting biologic drug therapy. Two blinded radiologists used the sMaRIA to score images obtained at baseline and week 46 of treatment first using only unenhanced sequences (T2-sMaRIA) and 1 month later using both unenhanced and enhanced images (CE-sMaRIA). We calculated the rates of agreement between T2-sMaRIA, CE-sMaRIA, and ileocolonoscopy for different conceptualizations of therapeutic response., Results: A total of 46 patients (median age, 36 years [IQR: 28-47]) were included. Agreement with ileocolonoscopy was similar for CE-sMaRIA and T2-sMaRIA in identifying ulcer healing (kappa = 0.74 [0.55-0.93] and 0.70 [0.5-0.9], respectively), treatment response (kappa = 0.53 [0.28-0.79] and 0.44 [0.17 - 0.71]), and remission (kappa = 0.48 [0.22-0.73] and 0.43 [0.17-0.69]). The standardized effect size was moderate for both CE-sMaRIA = 0.63 [0.41-0.85] p < 0.001 and T2-sMaRIA = 0.58 [0.36-0.80] p < 0.001., Conclusions: sMaRIA with and without contrast-enhanced images accurately classified the response according to different therapeutic endpoints determined by ileocolonoscopy., Key Points: • The simplified Magnetic Resonance Index of Activity is accurate for the assessment of Crohn's disease activity, severity, and therapeutic response, using four dichotomic components that can be evaluated without the need of using contrast-enhanced sequences, representing a practical and safety advantage, but concerns have been expressed as to whether the lack of contrast sequences may compromise precision. • The simplified Magnetic Resonance Index of Activity can assess the response to biologic therapy in patients with Crohn's disease without the need for intravenous contrast agents obtaining comparable results without and with contrast-enhanced sequences. • Avoiding intravenous contrast agents could reduce the duration of the MRE examination and its cost and would increase the acceptance and safety of MRE in clinical research in patients with Crohn's disease., (© 2021. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: Liver Imaging Reporting and Data System (LI-RADS) for hepatocellular carcinoma (HCC) diagnosis in high-risk patients is a dynamic system, which was lastly updated in 2018. We aimed to evaluate the accuracy for HCC diagnosis of LI-RADS v2018 with magnetic resonance imaging (MRI) with extracellular contrast for solitary nodules ≤ 20 mm detected during ultrasound (US) surveillance in cirrhotic patients, with particular interest in those observations categorized as LI-RADS 3., Methods: Between November 2003 and February 2017, we included 262 consecutive cirrhotic patients with a newly US-detected solitary ≤ 20-mm nodule. A LI-RADS (LR) v2018 category was retrospectively assigned. The diagnostic accuracy for each LR category was described, and the main MRI findings associated with HCC diagnosis were analyzed., Results: Final diagnoses were as follows: 197 HCC (75.2%), 5 cholangiocarcinoma (1.9%), 2 metastasis (0.8%), and 58 benign lesions (22.1%); 0/15 (0%) LR-1, 6/26 (23.1%) LR-2, 51/74 (68.9%) LR-3, 11/12 (91.7%) LR-4, 126/127 (99.2%) LR-5, and 3/8 (37.5%) LR-M were HCC. LR-5 category displayed a sensitivity and specificity of 64% (95% CI, 56.8-70.7) and 98.5% (95% CI, 91.7-100), respectively. Considering also LR-4 as diagnostic for HCC, the sensitivity slightly increased to 69.5% (95% CI, 62.6-75.9) with minor impact on specificity (96.2%; 95% CI, 89.3-99.6). Regarding LR-3 observations, 51 out of 74 were HCC, 2 were non-HCC malignancies, and 20 out of 21 LR-3 nodules > 15 mm (95.2%) were finally categorized as HCC., Conclusions: The high probability of HCC in US-detected LR-3 observations (68.9%) justifies triggering an active diagnostic work-up if intended to diagnose HCC at a very early stage., Key Points: • In cirrhotic patients with nodules ≤ 20 mm detected during US surveillance, 51 out of 74 (68.9%) of LR-3 nodules by MRI corresponded to an HCC. • In LR-3 nodules, HCC diagnosis was closely related to baseline tumor size. All 5 nodules smaller than 1 cm were diagnosed as benign. Oppositely, 20 out of 21 LR-3 observations > 15 mm (95.2%) were diagnosed as HCC. • The high probability of HCC in US-detected LR-3 observations justifies triggering an active diagnostic work-up if intended to diagnose HCC at a very early stage.

Objective: To compare the frequency of transient arterial-phase respiratory-motion-related artifacts in liver MRI after extracellular gadolinium and gadoxetic acid injection, and to determine the impact of these artifacts on the detection of focal areas of enhancement on arterial-phase images., Materials and Methods: Intra-patient comparison of 82 cirrhotic patients who prospectively underwent liver MR with extracellular gadolinium and with gadoxetic acid within 1 month. Two readers independently assessed the quality of dynamic T1-weighted MR images (pre-contrast, arterial, and portal-venous phases), rating respiratory-motion-related artifacts on four-point scale (0 [none]-3 [non-diagnostic]). We dichotomized these assessments, which were compared using McNemar's test, defining transient arterial-phase respiratory-motion-related artifacts as a study with a pre-contrast score < 2 and arterial-phase score ≥ 2. Readers also recorded whether at least one focal area of enhancement ≥ 10 mm on arterial phase was present., Results: The quality of arterial-phase images was worse when obtained after gadoxetic acid than after extracellular gadolinium (p < 0.01), and transient arterial-phase respiratory-motion-related artifacts were more common after gadoxetic acid than after extracellular gadolinium (p < 0.02). At least one area of arterial-phase enhancement ≥ 10 mm was detected more often after extracellular gadolinium than after gadoxetic acid. We observed significant differences on the comparison of the distributions of the presence of arterial-phase artifacts against the presence of arterial-phase enhancement ≥ 10 mm between the two contrast agents (p < 0.0001)., Conclusion: In cirrhotic patients, transient arterial-phase respiratory-motion-related artifacts are more common after gadoxetic acid than after extracellular gadolinium. Worse detection of arterial-phase enhancement on gadoxetic acid is only partly due to these artifacts., Key Points: • In a patient-by-patient analysis, the quality of arterial-phase liver MR images was significantly worse with gadoxetic acid than with extracellular gadolinium. • The frequency of transient arterial-phase artifacts was significantly higher after gadoxetic acid injection than after extracellular gadolinium injection. • Differences in the detection of areas of arterial-phase enhancement between MRI studies done with extracellular gadolinium and those done with gadoxetic acid might not be related only to image quality.

Objectives: Identifying inflammation- or fibrosis-predominant strictures in Crohn's disease (CD) is crucial for treatment strategies. We evaluated the additive value of magnetisation transfer (MT) to conventional MRI for differentiating CD strictures using surgical histopathology as a reference standard., Methods: Twenty-eight consecutive CD patients who underwent MRI preoperatively were recruited. MRI parameters included T2-weighted imaging (T2WI) hyperintensity, bowel wall thickness, enhancement pattern changes over time, enhancement pattern and gain ratio in dynamic contrast-enhanced phases, and MT ratio. Correlation analysis was performed using Spearman's rank test. Receiver operating characteristic curve analysis and Cohen's κ were used. A model with combined MRI variables characterising intestinal strictures was proposed and validated in 14 additional CD patients., Results: Significant correlations with histological inflammation scores were shown for wall thickness (r = 0.361, p = 0.001) and T2WI hyperintensity (r = 0.396, p < 0.001), whereas histological fibrosis scores were significantly correlated with MT ratio (r = 0.681, p < 0.001) and wall thickness (r = 0.461, p < 0.001). T2WI hyperintensity could differentiate mild from moderate-to-severe inflammation with a sensitivity of 0.871 and a specificity of 0.800. MT ratio could discriminate mild from moderate-to-severe fibrosis with a sensitivity and a specificity of 0.913 and 0.923, respectively. Combining MT ratio and T2WI hyperintensity, the MRI classification moderately agreed with the pathological stricture classification (p < 0.01, κ = 0.549). In the validation set, the diagnostic accuracy of T2WI hyperintensity and MT ratio were 86% and 89%, with good agreement between MRI and histopathological classification (p < 0.01, κ = 0.665)., Conclusions: MT ratio combined with conventional MRI improves the differentiation of fibrotic from inflammatory components of small-bowel strictures in CD patients., Key Points: • MT ratio from magnetisation transfer imaging combined with T2WI from conventional MRI can simultaneously characterise bowel fibrosis and inflammation in adult Crohn's disease.

Objective: To determine the diagnostic accuracy and predictive value of gadoxetic acid liver MRI (Gd-EOB-DTPA MRI) alone or in combination with diffusion-weighted imaging (DWI) as a second-line tool for detecting early hepatocellular carcinoma (HCC) recurrence in cirrhotic patients with previous HCC treated with resection or ablation., Methods: Between 2014 and 2017, we prospectively included 34 cirrhotic patients with complete response to resection and/or ablation of early HCC in whom a new focal lesion enhancing in the arterial phase without washout was detected during follow-up with EC-MRI. After signing the informed consent, all patients underwent DWI and Gd-EOB-DTPA MRI; two readers analyzed signal intensities on each phase of dynamic study and on DWI. The final diagnosis was established by histology or follow-up EC-MRI. We used cross-tabulation to calculate indices of diagnostic accuracy., Results: We evaluated 34 patients (7 women; 73.5% with hepatitis C virus) with a total of 53 new arterial-phase-enhancing foci (median size, 10 [IQR 9-14] mm). The final diagnosis, reached by histopathology in 15 (35.7%) lesions and EC-MR follow-up in 27 (64.3%), was HCC in 42 (79.2%) and benign conditions in 11 (21.8%). Hepatobiliary-phase hypointensity on Gd-EOB-DTPA MRI plus hyperintensity on DWI yielded 54.8% sensitivity, 90.9% specificity, 95.8% positive predictive value, and 34.5% negative predictive value for diagnosing HCC recurrence., Conclusion: Among potential indices, combining hypointensity on hepatobiliary-phase Gd-EOB-DTPA MRI and hyperintensity on DWI has the highest specificity and positive predictive value to optimally detect HCC recurrence prior to confident diagnosis by conventional imaging criteria on EC-MRI in cirrhotic liver., Key Points: • In patients at risk of HCC recurrence, the use of gadoxetic acid liver MRI and DWI may improve the differentiation of unspecific new arterial-enhancing foci from early hypervascular HCC recurrence in patients with non-conclusive findings on extracellular liver MRI. • Combined findings on hepatobiliary-phase gadoxetic acid-enhanced liver MRI and DWI had high specificity (90.9%) and positive predictive value (95.8%) for detecting early hypervascular HCC recurrence, but limited sensitivity. • Combining hepatobiliary-phase hypointensity on gadoxetic acid MRI and hyperintensity on diffusion-weighted imaging allows early diagnosis of hypervascular hepatocellular carcinoma and may help select patients for salvage therapy.