Purpose
To assess the agreement between published magnetic resonance imaging (MRI)‐based regions of interest (ROI) sampling methods using liver mean proton density fat fraction (PDFF) as the ...reference standard.
Materials and Methods
This retrospective, internal review board‐approved study was conducted in 35 patients with type 2 diabetes. Liver PDFF was measured by magnetic resonance spectroscopy (MRS) using a stimulated‐echo acquisition mode sequence and MRI using a multiecho spoiled gradient‐recalled echo sequence at 3.0T. ROI sampling methods reported in the literature were reproduced and liver mean PDFF obtained by whole‐liver segmentation was used as the reference standard. Intraclass correlation coefficients (ICCs), Bland–Altman analysis, repeated‐measures analysis of variance (ANOVA), and paired t‐tests were performed.
Results
ICC between MRS and MRI‐PDFF was 0.916. Bland–Altman analysis showed excellent intermethod agreement with a bias of –1.5 ± 2.8%. The repeated‐measures ANOVA found no systematic variation of PDFF among the nine liver segments. The correlation between liver mean PDFF and ROI sampling methods was very good to excellent (0.873 to 0.975). Paired t‐tests revealed significant differences (P < 0.05) with ROI sampling methods that exclusively or predominantly sampled the right lobe. Significant correlations with mean PDFF were found with sampling methods that included higher number of segments, total area equal or larger than 5 cm2, or sampled both lobes (P = 0.001, 0.023, and 0.002, respectively).
Conclusion
MRI‐PDFF quantification methods should sample each liver segment in both lobes and include a total surface area equal or larger than 5 cm2 to provide a close estimate of the liver mean PDFF. J. Magn. Reson. Imaging 2016;43:1090–1099.
The Liver Imaging Reporting and Data System (LI-RADS) standardizes the interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). ...It assigns category codes reflecting relative probability of HCC to imaging-detected liver observations based on major and ancillary imaging features. LI-RADS also includes imaging features suggesting malignancy other than HCC. Supported and endorsed by the American College of Radiology (ACR), the system has been developed by a committee of radiologists, hepatologists, pathologists, surgeons, lexicon experts, and ACR staff, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Development of LI-RADS has been based on literature review, expert opinion, rounds of testing and iteration, and feedback from users. This article summarizes and assesses the quality of evidence supporting each LI-RADS major feature for diagnosis of HCC, as well as of the LI-RADS imaging features suggesting malignancy other than HCC. Based on the evidence, recommendations are provided for or against their continued inclusion in LI-RADS.
RSNA, 2017 Online supplemental material is available for this article.
Objectives
Liver volumetry has emerged as an important tool in clinical practice. Liver volume is assessed primarily via organ segmentation of computed tomography (CT) and magnetic resonance imaging ...(MRI) images. The goal of this paper is to provide an accessible overview of liver segmentation targeted at radiologists and other healthcare professionals.
Methods
Using images from CT and MRI, this paper reviews the indications for liver segmentation, technical approaches used in segmentation software and the developing roles of liver segmentation in clinical practice.
Results
Liver segmentation for volumetric assessment is indicated prior to major hepatectomy, portal vein embolisation, associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and transplant. Segmentation software can be categorised according to amount of user input involved: manual, semi-automated and fully automated. Manual segmentation is considered the “gold standard” in clinical practice and research, but is tedious and time-consuming. Increasingly automated segmentation approaches are more robust, but may suffer from certain segmentation pitfalls. Emerging applications of segmentation include surgical planning and integration with MRI-based biomarkers.
Conclusions
Liver segmentation has multiple clinical applications and is expanding in scope. Clinicians can employ semi-automated or fully automated segmentation options to more efficiently integrate volumetry into clinical practice.
Teaching points
•
Liver volume is assessed via organ segmentation on CT and MRI examinations.
•
Liver segmentation is used for volume assessment prior to major hepatic procedures.
•
Segmentation approaches may be categorised according to the amount of user input involved.
•
Emerging applications include surgical planning and integration with MRI-based biomarkers.
Free-breathing external beam radiotherapy remains challenging due to the complex elastic or irregular motion of abdominal organs, as imaging moving organs leads to the creation of motion blurring ...artifacts. In this paper, we propose a radial-based MRI reconstruction method from 3D free-breathing abdominal data using spatio-temporal geodesic trajectories, to quantify motion during radiotherapy. The prospective study was approved by the institutional review board and consent was obtained from all participants. A total of 25 healthy volunteers, 12 women and 13 men (38 years ± 12 standard deviation), and 11 liver cancer patients underwent imaging using a 3.0 T clinical MRI system. The radial acquisition based on golden-angle sparse sampling was performed using a 3D stack-of-stars gradient-echo sequence and reconstructed using a discretized piecewise spatio-temporal trajectory defined in a low-dimensional embedding, which tracks the inhale and exhale phases, allowing the separation between distinct motion phases. Liver displacement between phases as measured with the proposed radial approach based on the deformation vector fields was compared to a navigator-based approach. Images reconstructed with the proposed technique with 20 motion states and registered with the multiscale B-spline approach received on average the highest Likert scores for the overall image quality and visual SNR score 3.2 ± 0.3 (mean ± standard deviation), with liver displacement errors varying between 0.1 and 2.0 mm (mean 0.8 ± 0.6 mm). When compared to navigator-based approaches, the proposed method yields similar deformation vector field magnitudes and angle distributions, and with improved reconstruction accuracy based on mean squared errors.
Graphic Abstract
Schematic illustration of the proposed 4D-MRI reconstruction method based on radial golden-angle acquisitions and a respiration motion model from a manifold embedding used for motion tracking. First, data is extracted from the center of k-space using golden-angle sampling, which is then mapped onto a low-dimensional embedding, describing the relationship between neighboring samples in the breathing cycle. The trained model is then used to extract the respiratory motion signal for slice re-ordering. The process then improves the image quality through deformable image registration. Using a reference volume, the deformation vector field (DVF) of sequential motion states are extracted, followed by deformable registrations. The output is a 4DMRI which allows to visualize and quantify motion during free-breathing.
Background
Pelvic ultrasound (US) diagnosis of uterine fibroids may overlook coexisting gynecological conditions that contribute to women's symptoms.
Purpose
To determine the added value of pelvic ...MRI for women diagnosed with symptomatic fibroids by US, and to identify clinical factors associated with additional MRI findings.
Study Type
Retrospective observational study.
Population
In all, 367 consecutive women with fibroids diagnosed by US and referred to our multidisciplinary fibroid center between 2013–2017.
Field Strength/Sequence
All patients had both pelvic US and MRI prior to their consultations. MRIs were performed at 1.5 T or 3 T and included multiplanar T2‐weighted sequences, and precontrast and postcontrast T1‐weighted imaging.
Assessment
Demographics, symptoms, uterine fibroid symptom severity scores, and health‐related quality of life scores, as well as imaging findings were evaluated.
Statistical Tests
Patients were separated into two subgroups according to whether MRI provided additional findings to the initial US. Univariate and multivariate regression analyses were performed.
Results
Pelvic MRI provided additional information in 162 patients (44%; 95% confidence interval CI 39–49%). The most common significant findings were adenomyosis (22%), endometriosis (17%), and partially endocavitary fibroids (15%). Women with pelvic pain, health‐related quality of life scores less than 30 out of 100, or multiple fibroids visualized on US had greater odds of additional MRI findings (odds ratio OR 1.68, 2.26, 1.63; P = 0.02, 0.004, 0.03, respectively), while nulliparous women had reduced odds (OR 0.55, P = 0.01). Patients with additional MRI findings were treated less often with uterine fibroid embolization (14% vs. 36%, P < 0.001) or MR‐guided focused US (1% vs. 5%, P = 0.04), and more often with medical management (17% vs. 8%, P = 0.01).
Data Conclusion
Pelvic MRI revealed additional findings in more than 40% of women presenting with symptoms initially ascribed to fibroids by US. Further evaluation using MRI is particularly useful for parous women with pelvic pain, poor quality of life scores, and/or multiple fibroids.
Level of Evidence: 4
Technical Efficacy: Stage 3
J. Magn. Reson. Imaging 2019.
A 25-year-old woman with a history of Crohn’s disease (CD) was evaluated in the Emergency Department for fevers, a persistent cough for several months, and abdominal cramps. Chest radiography and ...laboratory testing confirmed active tuberculosis (TB). She had been diagnosed with CD by colonoscopy and biopsy 3 years prior, due to complaints of abdominal pain, cramping, and diarrhea combined with a family history of CD. Her gastroenterologist treated her with adalimumab following screening for TB, which improved her gastrointestinal symptoms. One year later, disease progression, evidenced by extensive rectosigmoid ulcerations, prompted a switch to infiximab infusions.
Cystic Fibrosis (CF) is the most common lethal genetic disorder in Caucasian populations, affecting roughly 70,000 individuals worldwide. This autosomal recessive disorder causes a wide spectrum of ...multisystemic manifestations, most of which are either directly or indirectly related to defective epithelial chloride secretion. The current median life expectancy is 44 years; however, a significant proportion of the CF population now live into the 5th decade and beyond due to advances in treatment. As life expectancy of CF patients increases, there is a newly emerging adult CF population with unique radiological manifestations spanning multiple organ systems, which often require follow-up imaging. The goal of this article is to review the multiple systemic manifestations and complications of CF on different imaging modalities and explore the appropriate radiological follow up recommended.
•Review the pathophysiology, genetics, demographics, diagnosis, and treatment of cystic fibrosis (CF)•Demonstrate the role of imaging (radiograph, CT, MR, ultrasound) in the diagnosis and management of patients with CF•Learn the appropriate imaging follow-up for these patients•Help improve radiology reports for patients with CF•Educate about recent advances in research
Objective
To identify variables predictive of durable clinical success after MRI-guided focused ultrasound (MRgFUS) treatment of uterine fibroids.
Materials and methods
In this prospective, ...multicenter trial, 99 women with symptomatic uterine fibroids were treated using MRgFUS. Pelvic MRI was obtained at baseline and treatment day. The Uterine Fibroid Symptom-Quality of Life questionnaire was used to calculate a symptom severity score (SSS) at baseline and 6, 12, 24, and 36 months following treatment. Clinical, imaging, and treatment variables were correlated with symptom reduction sustained through the 12- and 24-month time points using univariable and multivariable logistic regression analyses. A novel parameter, the ratio of non-perfused volume to total fibroid load (NPV/TFL), was developed to determine association with durable outcomes.
Results
Post-treatment, mean symptom severity decreased at the 6-, 12-, 24-, and 36-month follow-ups (
p
< 0.001, all time points). In univariable analysis, three variables predicted treatment success (defined by ≥ 30-point improvement in SSS) sustained at both the 12-month and 24-month time points: increasing ratio of NPV/TFL (
p
= 0.002), decreasing total fibroid load (
p
= 0.04), and the absence of T2-weighted Funaki type 2 fibroids (
p
= 0.02). In multivariable analysis, the NPV/TFL was the sole predictor of durable clinical success (
p
= 0.01). Patients with ratios below 30% had less improvement in SSS and lacked durable clinical response compared with those between 30–79 (
p
= 0.03) and ≥ 80% (
p
= 0.01).
Conclusion
Increased non-perfused volume relative to total fibroid volume was significantly associated with durable reduction of symptoms of abnormal uterine bleeding and bulk bother.
Clinical relevance statement
Patient selection for sustained clinical benefit should emphasize those with likelihood of achieving high ablation ratios, as determined by imaging (e.g., device access, Funaki type) and by considering the total fibroid load, not just the primary symptomatic fibroid.
Trial registration
Clinical trial ID: NCT01285960.
Key Points
•
Patient selection/treatment approach associated with durable symptom relief in MRI-guided focused ultrasound ablation of uterine fibroids remains unclear.
•
The ablation ratio, non-perfused volume/total fibroid volume, was positively associated with sustained symptom relief in both bleeding and bulk bother at 1- and 2-year follow-ups.
•
Selecting patients with imaging features that favor a high ratio of ablation to total fibroid load (including non-targeted fibroids) is the main factor in predicting durability of symptom relief after uterine fibroid treatment.
Graphical abstract
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