Four-dimensional Flow MRI as a Marker for Risk Stratification of Gastroesophageal Varices in Patients with Liver Cirrhosis

Prediction Modelling for Gastroesophageal Variceal Bleeding in Patients With Chronic Hepatitis B Using Four-dimensional Flow MRI

Background/Aims

In this study, we aim to develop a model for predicting gastroesophageal varices (GEV) bleeding in patients with chronic hepatitis B (CHB) by utilizing hemodynamic parameters obtained through four-dimensional flow MRI (4D flow MRI).

Methods

This study conducted a prospective enrollment of CHB patients suspected of GEV from October 2021 to May 2022. The severity of varices and bleeding risk were evaluated using clinical findings and upper gastrointestinal endoscopy, and patients were classified into high-risk and non-high-risk groups. The study utilized serological examination, ultrasonographic examination, and 4D flow MRI. Relevant parameters were selected through univariate and multivariate analyses, and a prediction model was established using binary logistic regression analysis. The model was combined with the Baveno Ⅵ/Ⅶ and Expanded Baveno Ⅵ/Ⅶ criteria to evaluate diagnostic efficacy and the risk of avoiding endoscopic examination.

Results

A total of 40 CHB patients were enrolled and categorized into the high-risk group (n = 15) and the non-high-risk group (n = 25). The spleen diameter and regurgitant fraction (R%) were independent predictors of variceal bleeding and a predictive model was established. The combination of this prediction model and the Baveno Ⅵ/Ⅶ criteria achieved high diagnostic efficiency, enabling 45.00% (18/40) of patients to be exempted from the unnecessary endoscopic procedure and the high-risk misclassification rate (0%) was less than 5%.

Conclusion

The prediction model generated by 4D flow MRI has the potential to assess the likelihood of varices and can be supplemented by the Baveno VI/VII criteria to improve diagnostic accuracy in CHB patients.

Quantifying and visualizing abdominal hemodynamics in patients with Fontan circulation by 4D phase-contrast flow magnetic resonance imaging at 1.5 T

BACKGROUND

Liver fibrosis has been recognized as a long-term morbidity associated with Fontan circulation (Fontan-associated liver disease, FALD). The pathophysiology of FALD is not completely understood and abnormal flow dynamics may be associated with this condition. Liver hemodynamics can be quantitatively evaluated with four-dimensional phase-contrast flow magnetic resonance imaging (4D PC flow MRI). The study aimed to evaluate suitability of liver 4D PC flow MRI in Fontan patients and relate flow measurements to normal values and FALD severity.

PATIENTS AND METHODS

Twenty-two Fontan patients were examined by 4D PC flow MRI at 1.5 Tesla to assess mesenteric, portal, splenic, and hepatic venous blood flow. Severity of FALD was graded based on routine screening, including abdominal ultrasound and laboratory tests.

RESULTS

Median age was 18.5 (interquartile range, IQR 15.5-20.2) years. FALD was graded as "none or mild" in 16 and as "moderate to severe" in six cases. Ten patients presented at least one feature of portal hypertension (ascites, splenomegaly, or thrombocytopenia). For the entire cohort, blood flow in the superior mesenteric, splenic, and portal vein was lower than reported in the literature. No significant differences were observed in relation to FALD severity. Features of portal hypertension were associated with a higher splenic vein blood flow (0.34 ± 0.17 vs. 0.20 ± 0.07 l/min, p = 0.046). Splenic vein blood flow was negatively correlated to platelet count (r = -0.590, p = 0.005).

CONCLUSIONS

4D PC flow MRI appears suitable to assess liver hemodynamics in Fontan patients and integration into clinical follow-up might help to improve our understanding of FALD.

Non-contrast MR angiography: physical principles and clinical applications in chest, abdomen and pelvis imaging

This review article focuses on the advancements in non-contrast magnetic resonance angiography (NC-MRA) and its increasing importance in body imaging, especially for patients with renal complications, pregnant women, and children. It highlights the relevance of NC-MRA in chest, abdominal, and pelvis imaging and details various bright-blood NC-MRA techniques like cardiac-gated 3D Fast Spin Echo (FSE), balanced Steady-State Free Precession (bSSFP), Arterial Spin Labeling (ASL), and 4D flow methods. The article explains the operational principles of these techniques, their clinical applications, and their advantages over traditional contrast-enhanced methods. Special attention is given to the utility of these techniques in diverse imaging scenarios, including liver, renal, and pelvic imaging. The article underscores the growing importance of NC-MRA in medical diagnostics, offering insights into current practices and potential future developments. This comprehensive review is a valuable resource for radiologists and clinicians, emphasizing NC-MRA's role in enhancing patient care and diagnostic accuracy across various medical conditions.

Non-contrast-enhanced MR angiography of left gastric vein in patients with gastroesophageal varices: morphology and blood supply analysis

OBJECTIVES

To investigate the feasibility of non-contrast-enhanced MR angiography (NCE-MRA) in evaluating the morphology and blood supply of left gastric vein (LGV) in patients with gastroesophageal varices.

METHODS

Between March 2021 and October 2022, patients with gastroesophageal varices and who underwent NCE-MRA were retrospectively reviewed. In order to evaluate the blood supply of LGV, superior mesenteric vein (SMV) and splenic vein (SV) were visualized separately by using inflow-sensitive inversion recovery sequence. Two radiologists independently assessed the image quality, determined the origination and the blood supply of LGV, and measured the diameter of LGV. The origination and diameter of LGV were compared between NCE-MRA and contrast-enhanced CT. Differences in blood supply were compared between LGVs with different originations.

RESULTS

A total of 53 patients were enrolled in this study and the image quality was categorized as good or excellent in 52 patients. No significant differences were observed in visualizing the origination and the diameter of LGV between NCE-MRA and contrast-enhanced CT (p > .05). The blood supply of LGV was related to its origination (p < .001). Most LGVs with SV origination were supplied by SV. If LGV was originated from the portal vein (PV), about 70% of them were supplied by both SV and SMV. Compared with LGVs with SV origination, LGVs with PV origination showed more chance to receive blood from SMV (p < .001).

CONCLUSION

Non-contrast-enhanced MR angiography appears to be a reliable technique in evaluating the morphology and blood supply of LGV in patients with gastroesophageal varices.

CLINICAL RELEVANCE STATEMENT

Non-contrast-enhanced MR angiography provides valuable information for the management of gastroesophageal varices. Especially, it benefits patients with renal insufficiency.

KEY POINTS

• Non-contrast-enhanced MR angiography using inflow-sensitive inversion recovery technique can be used for evaluating not only morphology as CT but also blood supply of left gastric vein. • The blood supply of left gastric vein is related to its origination and left gastric vein with portal vein origination shows more chance to receive blood from superior mesenteric vein.

Differentiation Between the Low and High Trans-Stenotic Pressure Gradient in Patients With Idiopathic Intracranial Hypertension Using 4D Flow MRI-Derived Hemodynamic Parameters

BACKGROUND

Trans-stenotic pressure gradient (TPG) measurement is essential for idiopathic intracranial hypertension (IIH) patients with transverse sinus (TS) stenosis. Four-D flow MRI may provide a noninvasive imaging method for differentiation of IIH patients with different TPG.

PURPOSE

To investigate the associations between 4D flow parameters and TPG, and to evaluate the diagnostic performance of 4D flow parameters in differentiating patients with high TPG (GroupHP) from low TPG (GroupLP).

STUDY TYPE

Prospective.

POPULATION

31 IIH patients with TS stenosis (age, 38 ± 12 years; 23 females) and 5 healthy volunteers (age, 25 ± 1 years; 2 females).

FIELD STRENGTH/SEQUENCE

3T, 3D phase contrast MR venography, and gradient recalled echo 4D flow sequences.

ASSESSMENT

Scan-rescan reproducibility of 4D flow parameters were performed. The correlation between TPG and flow parameters was analyzed. The netflow and velocity difference between inflow plane, outflow plane, and the stenosis plane were calculated and compared between GroupHP and GroupLP.

STATISTICAL TESTS

Pearson's correlation or Spearman's rank correlation coefficient, Independent samples t-test or Wilcoxon rank-sum test, Intra-class correlation coefficient (ICC), Bland-Altman analyses, Receiver operating characteristic curves. A P value <0.05 was considered significant.

RESULTS

Significant correlations were found between TPG and netflow parameters including Favg,out-s, Favg,in-s, Fmax,out-s, and Fmax,in-s (r = 0.525-0.565). Significant differences were found in Favg,out-s, Fmax,out-s, Favg,in-s, and Fmax,in-s between GroupHP and GroupLP. Using the cut-off value of 2.19 mL/sec, the Favg,out-s showed good estimate performance in distinguishing GroupHP from GroupLP (AUC = 0.856). The ICC (ranged 0.905-0.948) and Bland-Altman plots indicated good scan-rescan reproducibility.

DATA CONCLUSIONS

4D flow MRI derived flow parameters showed good correlations with TPG in IIH patients with TS stenosis. Netflow difference between outflow and stenosis location at TS shows the good performance in differentiating GroupHP and GroupLP cases.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Evaluation of 4D Flow MRI-Derived Relative Residence Time as a Marker for Cirrhosis Associated Portal Vein Thrombosis

BACKGROUND

Portal vein thrombosis (PVT) is thought to arise from stagnant blood flow, yet conclusive evidence is lacking. Relative residence time (RRT) assessed using 4D Flow MRI may offer insight into portal flow stagnation.

PURPOSE

To explore the relationship between RRT values and the presence of PVT in cirrhotic participants.

STUDY TYPE

Prospective.

POPULATION

Forty-eight participants with liver cirrhosis (27 males, median age 67 years [IQR: 57-73]) and 20 healthy control participants (12 males, median age 45 years [IQR: 40-54]).

FIELD STRENGTH/SEQUENCE

3 T/4D Flow MRI.

ASSESSMENT

Laboratory (liver and kidney function test results and platelet count) and clinical data (presence of tumors and other imaging findings), and portal hemodynamics derived from 4D Flow MRI (spatiotemporally averaged RRT [RRT-mean], flow velocity, and flow rate) were analyzed.

STATISTICAL TESTS

We used multivariable logistic regression, adjusted by selected covariates through the Lasso method, to explore whether RRT-mean is an independent risk factor for PVT. The area under the ROC curve (AUC) was also calculated to assess the model's discriminative ability. P < 0.05 indicated statistical significance.

RESULTS

The liver cirrhosis group consisted of 16 participants with PVT and 32 without PVT. Higher RRT-mean values (odds ratio [OR] 11.4 [95% CI: 2.19, 118]) and lower platelet count (OR 0.98 per 1000 μL [95% CI: 0.96, 0.99]) were independent risk factors for PVT. The incorporation of RRT-mean (AUC, 0.77) alongside platelet count (AUC, 0.75) resulted in an AUC of 0.84. When including healthy control participants, RRT-mean had an adjusted OR of 12.4 and the AUC of the combined model (RRT-mean and platelet count) was 0.90.

DATA CONCLUSION

Prolonged RRT values and low platelet count were significantly associated with the presence of PVT in cirrhotic participants. RRT values derived from 4D Flow MRI may have potential clinical relevance in the management of PVT.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Revolutionizing vascular imaging: trends and future directions of 4D flow MRI based on a 20-year bibliometric analysis

Background

Four-dimensional flow magnetic resonance imaging (4D flow MRI) is a promising new technology with potential clinical value in hemodynamic quantification. Although an increasing number of articles on 4D flow MRI have been published over the past decades, few studies have statistically analyzed these published articles. In this study, we aimed to perform a systematic and comprehensive bibliometric analysis of 4D flow MRI to explore the current hotspots and potential future directions.

Methods

The Web of Science Core Collection searched for literature on 4D flow MRI between 2003 and 2022. CiteSpace was utilized to analyze the literature data, including co-citation, cooperative network, cluster, and burst keyword analysis.

Results

A total of 1,069 articles were extracted for this study. The main research hotspots included the following: quantification and visualization of blood flow in different clinical settings, with keywords such as "cerebral aneurysm", "heart", "great vessel", "tetralogy of Fallot", "portal hypertension", and "stiffness"; optimization of image acquisition schemes, such as "resolution" and "reconstruction"; measurement and analysis of flow components and patterns, as indicated by keywords "pattern", "KE", "WSS", and "fluid dynamics". In addition, international consensus for metrics derived from 4D flow MRI and multimodality imaging may also be the future research direction.

Conclusions

The global domain of 4D flow MRI has grown over the last 2 decades. In the future, 4D flow MRI will evolve towards becoming a relatively short scan duration with adequate spatiotemporal resolution, expansion into the diagnosis and treatment of vascular disease in other related organs, and a shift in focus from vascular structure to function. In addition, artificial intelligence (AI) will assist in the clinical promotion and application of 4D flow MRI.

Current Imaging Strategies in Patients with Abdominal Aortic Aneurysms

BACKGROUND

 An abdominal aortic aneurysm (AAA) is defined as a localized dilatation of the abdominal aorta of ≥ 3 cm. With a prevalence of 4-8 %, AAA is one of the most common vascular diseases in Western society. Radiological imaging is an elementary component in the diagnosis, monitoring, and treatment planning of AAA patients.

METHOD

 This is a narrative review article on preoperative imaging strategies of AAA, incorporating expert opinions based on the current literature and standard-of-care practices from our own center. Examples are provided to illustrate clinical cases from our institution.

RESULTS AND CONCLUSION

 Radiological imaging plays a pivotal role in the initial diagnosis and monitoring of patients with AAA. Ultrasound is the mainstay imaging modality for AAA screening and surveillance. Contrast-enhanced CT angiography is currently considered the gold standard for preoperative imaging and image-based treatment planning in AAA repair. New non-contrast MR angiography techniques are robustly applicable and allow precise determination of aortic diameters, which is of critical importance, particularly with regard to current diameter-based surgical treatment guidelines. 3D imaging with multiplanar reformation and automatic centerline positioning enables more accurate assessment of the maximum aortic diameter. Modern imaging techniques such as 4D flow MRI have the potential to further improve individualized risk stratification in patients with AAA.

KEY POINTS

  · Ultrasound is the mainstay imaging modality for AAA screening and monitoring. · Contrast-enhanced CT angiography is the gold standard for preoperative imaging in AAA repair. · Non-contrast MR angiography allows for accurate monitoring of aortic diameters in AAA patients. · Measurement of aortic diameters is more accurate with 3D-CT/MRI compared to ultrasound. · Research seeks new quantitative imaging biomarkers for AAA risk stratification, e. g., using 4D flow MRI.

Four-dimensional Flow MRI Assessment of Portal Hemodynamics and Hepatic Regeneration after Portal Vein Embolization

Background Percutaneous transhepatic portal vein (PV) embolization (PVE) is a standard preoperative procedure for advanced biliary cancer when the future liver remnant (FLR) is insufficient, yet the effect of this procedure on portal hemodynamics is still unclear. Purpose To assess whether four-dimensional (4D) MRI flowmetry can be used to estimate FLR volume and to identify the optimal time for this measurement. Materials and Methods This prospective single-center study enrolled consecutive adult patients with biliary cancer who underwent percutaneous transhepatic PVE for the right liver between June 2020 and November 2022. Portal hemodynamics were assessed using 4D flow MRI before PVE and within 1 day (0-day group) or 3-4 days (3-day group) after PVE. FLR volume was measured using CT before PVE and after PVE but before surgery. Blood flow changes were analyzed with the Wilcoxon signed rank test, and correlations with Spearman rank correlation. Results The 0-day group included 24 participants (median age, 72 years [IQR, 69-77 years]; 17 male participants), and the 3-day group included 13 participants (median age, 71 years [IQR, 68-78 years]; eight male participants). Both groups showed increased left PV (LPV) flow rate after PVE (0-day group: from median 3.72 mL/sec [IQR, 2.83-4.55 mL/sec] to 9.48 mL/sec [IQR, 8.12-10.7 mL/sec], P < .001; 3-day group: from median 3.65 mL/sec [IQR, 2.14-3.79 mL/sec] to 8.16 mL/sec [IQR, 6.82-8.98 mL/sec], P < .001). LPV flow change correlated with FLR volume change relative to the number of days from PVE to presurgery CT only in the 3-day group (ρ = 0.62, P = .02; 0-day group, P = .11). The output of the regression equation for estimating presurgery FLR volume correlated with CT-measured volume (ρ = 0.78; P = .002). Conclusion Four-dimensional flow MRI demonstrated increased blood flow in residual portal branches 3-4 days after PVE, offering insights for estimating presurgery FLR volume. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Roldán-Alzate and Oechtering in this issue.

Reference values for 4D flow magnetic resonance imaging of the portal venous system

PURPOSE

The purpose of this work was to establish normal reference values for 4D flow MRI-derived flow, velocity, and vessel diameters, and to define characteristic flow patterns in the portal venous system of healthy adult subjects.

METHODS

For this retrospective study, we screened all available 4D flow MRI exams of the upper abdomen in healthy adults acquired at our institution between 2012 and 2022 at either 1.5 T or 3.0 T MRI after ≥ 5 h fasting. Flow, velocity, and effective diameter were quantified in the 8 planes in the portal venous system (splenic vein, superior mesenteric vein, main, right, and left portal veins). Vessel delineation was manually adjusted over time. Reference ranges for were defined as the mean ± 2 standard deviations. Three readers noted helical and vortical flow on time-resolved pathline visualizations. Conservation of mass flow analysis was performed for quality assurance.

RESULTS

We included 44 healthy subjects (26 female, 18-74 years) in the analysis. We report reference values for mean and peak flow, mean velocity, and vessel diameter in the healthy portal vein using 4D flow MRI. Normal flow patterns in the portal vein included faint helical (66%) or linear flow (34%). Conservation of mass analysis demonstrated a relative error of 1.1 ± 4.6% standard deviation (SD) at the splenomesenteric confluence and - 1.4 ± 4.1% SD at the portal bifurcation.

CONCLUSION

We have reported normal hemodynamic values that are necessary baseline data for emerging clinical applications of 4D flow MRI in the portal venous system. Results are consistent with previously published values from smaller cohorts.

Liver cirrhosis in children - the role of imaging in the diagnostic pathway

Liver cirrhosis in children is a rare disease with multifactorial causes that are distinct from those in adults. Underlying reasons include cholestatic, viral, autoimmune, hereditary, metabolic and cardiac disorders. Early detection of fibrosis is important as clinical stabilization or even reversal of fibrosis can be achieved in some disorders with adequate treatment. This article focuses on the longitudinal evaluation of children with chronic liver disease with noninvasive imaging tools, which play an important role in detecting cirrhosis, defining underlying causes, grading fibrosis and monitoring patients during follow-up. Ultrasound is the primary imaging modality and it is used in a multiparametric fashion. Magnetic resonance imaging and computed tomography are usually applied second line for refined tissue characterization, clarification of nodular lesions and full delineation of abdominal vessels, including portosystemic communications.

Validation of 4D flow cardiovascular magnetic resonance in TIPS stent grafts using a 3D-printed flow phantom

BACKGROUND

Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) is feasible for portal blood flow evaluation after placement of transjugular intrahepatic portosystemic shunts (TIPS) in patients with liver cirrhosis. However, clinical acceptance of 4D flow CMR in TIPS patients is limited due to the lack of validation studies. The purpose of this study was to validate 4D flow CMR-derived measurements in TIPS stent grafts using a three-dimensional (3D)-printed flow phantom.

METHODS

A translucent flow phantom of the portal vasculature was 3D-printed. The phantom consisted of the superior mesenteric vein and the splenic vein draining into the portal vein, the TIPS-tract, and the hepatic vein. A TIPS stent graft (Gore® Viatorr®) was positioned within the TIPS-tract. Superior mesenteric vein and splenic vein served as inlets for blood-mimicking fluid. 4D flow CMR acquisitions were performed at 3T at preset flow rates of 0.8 to 2.8 l/min using velocity encoding of both 1.0 and 2.0 m/s. Flow rates and velocities were measured at predefined levels in the portal vasculature and within the stent graft. Accuracy of 4D flow CMR was assessed through linear regression with reference measurements obtained by flow sensors and two-dimensional (2D) phase contrast (PC) CMR. Intra- and interobserver agreement were assessed through Bland-Altman analyses.

RESULTS

At a velocity encoding of 2.0 m/s, 4D flow CMR-derived flow rates and velocities showed an excellent correlation with preset flow rates and 2D PC CMR-derived flow velocities at all vascular levels and within the stent graft (all r ≥ 0.958, p ≤ 0.003). At a velocity encoding of 1.0 m/s, aliasing artifacts were present within the stent graft at flow rates ≥ 2.0 l/min. 4D flow CMR-derived measurements revealed high intra- and interobserver agreement.

CONCLUSIONS

The in vitro accuracy and precision of 4D flow CMR is unaffected by the presence of TIPS stent grafts, suggesting that 4D flow CMR may be used to monitor TIPS patency in patients with liver cirrhosis.

Liver cirrhosis: relationship between fibrosis-associated hepatic morphological changes and portal hemodynamics using four-dimensional flow magnetic resonance imaging

PURPOSE

The mechanisms underlying the morphological changes in liver cirrhosis remain unknown. This study aimed to clarify the relationship between fibrotic hepatic morphology and portal hemodynamic changes using four-dimensional flow magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Overall, 100 patients with suspected liver disease who underwent 3-T MRI were evaluated in this retrospective study. Liver fibrosis was assessed using a combination of visual assessment of the hepatic morphology and quantitative measures, including the fibrosis-4 index and aspartate transaminase-to-platelet ratio. It was classified into three groups according to the severity of fibrosis as follows: A (normal), B (mild-to-moderate), and C (severe). Quantitative indices, including area (mm²), net flow (mL/s), and average velocity (cm/s), were measured in the right portal vein (RPV) and left portal vein (LPV), and were compared across the groups using the Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

Among the 100 patients (69.1 ± 12.1 years; 59 men), 45, 35, and 20 were categorized into groups A, B, and C, respectively. The RPV area significantly differed among the groups (from p < 0.001 to p = 0.001), showing a gradual decrease with fibrosis progression. Moreover, the net flow significantly differed between groups A and B and between groups A and C (p < 0.001 and p < 0.001, respectively), showing a decrease during the early stage of fibrosis. In the LPV, the net flow significantly differed among the groups (from p = 0.001 to p = 0.030), revealing a gradual increase with fibrosis progression.

CONCLUSION

The atrophy-hypertrophy complex, which is a characteristic imaging finding in advanced cirrhosis, was closely associated with decreased RPV flow in the early stage of fibrosis and a gradual increase in LPV flow across all stages of fibrosis progression.

4D flow MRI in abdominal vessels: prospective comparison of k-t accelerated free breathing acquisition to standard respiratory navigator gated acquisition

Volumetric phase-contrast magnetic resonance imaging with three-dimensional velocity encoding (4D flow MRI) has shown utility as a non-invasive tool to examine altered blood flow in chronic liver disease. Novel 4D flow MRI pulse sequences with spatio-temporal acceleration can mitigate the long acquisition times of standard 4D flow MRI, which are an impediment to clinical adoption. The purpose of our study was to demonstrate feasibility of a free-breathing, spatio-temporal (k-t) accelerated 4D flow MRI acquisition for flow quantification in abdominal vessels and to compare its image quality, flow quantification and inter-observer reproducibility with a standard respiratory navigator-gated 4D flow MRI acquisition. Ten prospectively enrolled patients (M/F: 7/3, mean age = 58y) with suspected portal hypertension underwent both 4D flow MRI acquisitions. The k-t accelerated acquisition was approximately three times faster (3:11 min ± 0:12 min/9:17 min ± 1:41 min, p < 0.001) than the standard respiratory-triggered acquisition. Vessel identification agreement was substantial between acquisitions and observers. Average flow had substantial inter-sequence agreement in the portal vein and aorta (CV < 15%) and poorer agreement in hepatic and splenic arteries (CV = 11-38%). The k-t accelerated acquisition recorded reduced velocities in small arteries and reduced splenic vein flow. Respiratory gating combined with increased acceleration and spatial resolution are needed to improve flow measurements in these vessels.

Kat-ARC accelerated 4D flow CMR: clinical validation for transvalvular flow and peak velocity assessment

BACKGROUND

To validate the k-adaptive-t autocalibrating reconstruction for Cartesian sampling (kat-ARC), an exclusive sparse reconstruction technique for four-dimensional (4D) flow cardiac magnetic resonance (CMR) using conservation of mass principle applied to transvalvular flow.

METHODS

This observational retrospective study (2020/21-075) was approved by the local ethics committee at the University of East Anglia. Consent was waived. Thirty-five patients who had a clinical CMR scan were included. CMR protocol included cine and 4D flow using Kat-ARC acceleration factor 6. No respiratory navigation was applied. For validation, the agreement between mitral net flow (MNF) and the aortic net flow (ANF) was investigated. Additionally, we checked the agreement between peak aortic valve velocity derived by 4D flow and that derived by continuous-wave Doppler echocardiography in 20 patients.

RESULTS

The median age of our patient population was 63 years (interquartile range [IQR] 54-73), and 18/35 (51%) were male. Seventeen (49%) patients had mitral regurgitation, and seven (20%) patients had aortic regurgitation. Mean acquisition time was 8 ± 4 min. MNF and ANF were comparable: 60 mL (51-78) versus 63 mL (57-77), p = 0.310). There was an association between MNF and ANF (rho = 0.58, p < 0.001). Peak aortic valve velocity by Doppler and 4D flow were comparable (1.40 m/s, [1.30-1.75] versus 1.46 m/s [1.25-2.11], p = 0.602) and also correlated with each other (rho = 0.77, p < 0.001).

CONCLUSIONS

Kat-ARC accelerated 4D flow CMR quantified transvalvular flow in accordance with the conservation of mass principle and is primed for clinical translation.

4D Flow MRI in the portal venous system: imaging and analysis methods, and clinical applications

Thus far, ultrasound, CT, and 2D cine phase-contrast MRI has been adopted to evaluate blood flow and vascular morphology in the portal venous system; however, all these techniques have some shortcomings, such as limited field of view and difficulty in accurately evaluating blood flow. A new imaging technique, namely 3D cine phase-contrast (4D Flow) MRI, can acquire blood flow data of the entire abdomen at once and in a time-resolved manner, allowing visual, quantitative, and comprehensive assessment of blood flow in the portal venous system. In addition, a retrospective blood flow analysis, i.e., "retrospective flowmetry," is possible. Although the development of 4D Flow MRI for the portal system has been delayed compared to that for the arterial system owing to the lower flow velocity of the portal venous system and the presence of respiratory artifacts, several useful reports have recently been published as the technology has advanced. In the first part of this narrative review article, technical considerations of image acquisition and analysis methods of 4D Flow MRI for the portal venous system and the validations of their results are described. In the second part, the current clinical application of 4D Flow MRI for the portal venous system is reviewed.

Bibliometric-analysis visualization and review of non-invasive methods for monitoring and managing the portal hypertension

Background

Portal hypertension monitoring is important throughout the natural course of cirrhosis. Hepatic venous pressure gradient (HVPG), regarded as the golden standard, is limited by invasiveness and technical difficulties. Portal hypertension is increasingly being assessed non-invasively, and hematological indices, imaging data, and statistical or computational models are studied to surrogate HVPG. This paper discusses the existing non-invasive methods based on measurement principles and reviews the methodological developments in the last 20 years.

Methods

First, we used VOSviewer to learn the architecture of this field. The publications about the non-invasive assessment of portal hypertension were retrieved from the Web of Science Core Collection (WoSCC). VOSviewer 1.6.17.0 was used to analyze and visualize these publications, including the annual trend, the study hotspots, the significant articles, authors, journals, and organizations in this field. Next, according to the cluster analysis result of the keywords, we further retrieved and classified the related studies to discuss.

Results

A total of 1,088 articles or review articles about our topic were retrieved from WoSCC. From 2000 to 2022, the number of publications is generally growing. “World Journal of Gastroenterology” published the most articles (n = 43), while “Journal of Hepatology” had the highest citations. “Liver fibrosis” published in 2005 was the most influential manuscript. Among the 20,558 cited references of 1,088 retrieved manuscripts, the most cited was a study on liver stiffness measurement from 2007. The highest-yielding country was the United States, followed by China and Italy. “Berzigotti, Annalisa” was the most prolific author and had the most cooperation partners. Four study directions emerged from the keyword clustering: (1) the evaluation based on fibrosis; (2) the evaluation based on hemodynamic factors; (3) the evaluation through elastography; and (4) the evaluation of variceal bleeding.

Conclusion

The non-invasive assessment of portal hypertension is mainly based on two principles: fibrosis and hemodynamics. Liver fibrosis is the major initiator of cirrhotic PH, while hemodynamic factors reflect secondary alteration of splanchnic blood flow. Blood tests, US (including DUS and CEUS), CT, and magnetic resonance imaging (MRI) support the non-invasive assessment of PH by providing both hemodynamic and fibrotic information. Elastography, mainly USE, is the most important method of PH monitoring.

Abdominal applications of quantitative 4D flow MRI

4D flow MRI is a quantitative MRI technique that allows the comprehensive assessment of time-resolved hemodynamics and vascular anatomy over a 3-dimensional imaging volume. It effectively combines several advantages of invasive and non-invasive imaging modalities like ultrasound, angiography, and computed tomography in a single MRI acquisition and provides an unprecedented characterization of velocity fields acquired non-invasively in vivo. Functional and morphological imaging of the abdominal vasculature is especially challenging due to its complex and variable anatomy with a wide range of vessel calibers and flow velocities and the need for large volumetric coverage. Despite these challenges, 4D flow MRI is a promising diagnostic and prognostic tool as many pathologies in the abdomen are associated with changes of either hemodynamics or morphology of arteries, veins, or the portal venous system. In this review article, we will discuss technical aspects of the implementation of abdominal 4D flow MRI ranging from patient preparation and acquisition protocol over post-processing and quality control to final data analysis. In recent years, the range of applications for 4D flow in the abdomen has increased profoundly. Therefore, we will review potential clinical applications and address their clinical importance, relevant quantitative and qualitative parameters, and unmet challenges.

Characterization of mesenteric and portal hemodynamics using 4D flow MRI: the effects of meals and diurnal variation

PURPOSE

To determine the variability of blood flow measurements using 4D flow MRI in the portal and mesenteric circulations and to characterize the effects of meal ingestion, time of day, and between-day (diurnal) variations on portal and mesenteric hemodynamics.

METHODS

In this IRB-approved and HIPAA-compliant study, 7 healthy and 7 portal hypertension patients imaged. MRI exams were conducted at 3 T using a 32-channel body coil with large volumetric coverage and 1.25-mm isotropic true spatial resolution. Blood flow was quantified (L/min) in the hepatic and splanchnic vasculature. The first MR scan was performed after at least 8 h of fasting. Subsequently, subjects ingested 574 mL EnSure Plus® orally. A second acquisition was started 20 min after the meal ingestion. A third scan was performed before lunch and a fourth acquisition took place 20 min after lunch. A fifth scan was performed around 4 pm. Finally, subjects returned one week later for a repeat morning visit, with identical conditions as the first visit.

RESULTS

In healthy controls significant increase in blood flow was seen in the PV, SMV, SMA, HA, and SCAo in response to breakfast but only the SCAo, SMA, SMV, and PV had a significant response to lunch. In general, patients with cirrhosis showed reduced response to meals compared to that in healthy controls. Additionally, PV flow in patients had the highest value in the afternoon.

CONCLUSION

Effects of meal ingestion, time of day, and between-day variations were characterized using Radial 4D flow MRI in patients with cirrhosis and healthy controls.

Noninvasive imaging of hepatic dysfunction: A state-of-the-art review

Hepatic dysfunction represents a wide spectrum of pathological changes, which can be frequently found in hepatitis, cholestasis, metabolic diseases, and focal liver lesions. As hepatic dysfunction is often clinically silent until advanced stages, there remains an unmet need to identify affected patients at early stages to enable individualized intervention which can improve prognosis. Passive liver function tests include biochemical parameters and clinical grading systems (e.g., the Child-Pugh score and Model for End-Stage Liver Disease score). Despite widely used and readily available, these approaches provide indirect and limited information regarding hepatic function. Dynamic quantitative tests of liver function are based on clearance capacity tests such as the indocyanine green (ICG) clearance test. However, controversial results have been reported for the ICG clearance test in relation with clinical outcome and the accuracy is easily affected by various factors. Imaging techniques, including ultrasound, computed tomography, and magnetic resonance imaging, allow morphological and functional assessment of the entire hepatobiliary system, hence demonstrating great potential in evaluating hepatic dysfunction noninvasively. In this article, we provide a state-of-the-art summary of noninvasive imaging modalities for hepatic dysfunction assessment along the pathophysiological track, with special emphasis on the imaging modality comparison and selection for each clinical scenario.

Clinical Applications of 4D Flow MRI in the Portal Venous System

Evaluation of the hemodynamics in the portal venous system plays an essential role in many hepatic pathologies. Changes in portal flow and vessel morphology are often indicative of disease.Routinely used imaging modalities, such as CT, ultrasound, invasive angiography, and MRI, often focus on either hemodynamics or anatomical imaging. In contrast, 4D flow MRI facilitiates a more comprehensive understanding of pathophysiological mechanisms by simultaneously and noninvasively acquiring time-resolved flow and anatomical information in a 3D imaging volume.Though promising, 4D flow MRI in the portal venous system is especially challenging due to small vessel calibers, slow flow velocities, and breathing motion. In this review article, we will discuss how to account for these challenges when planning and conducting 4D flow MRI acquisitions in the upper abdomen. We will address patient preparation, sequence acquisition, postprocessing, quality control, and analysis of 4D flow data.In the second part of this article, we will review potential clinical applications of 4D flow MRI in the portal venous system. The most promising area for clinical utilization is the diagnosis and grading of liver cirrhosis and its complications. Relevant parameters acquired by 4D flow MRI include the detection of reduced or reversed flow in the portal venous system, characterization of portosystemic collaterals, and impaired response to a meal challenge. In patients with cirrhosis, 4D flow MRI has the potential to address the major unmet need of noninvasive detection of gastroesophageal varices at high risk for bleeding. This could replace many unnecessary, purely diagnostic, and invasive esophagogastroduodenoscopy procedures, thereby improving patient compliance with follow-up. Moreover, 4D flow MRI offers unique insights and added value for surgical planning and follow-up of multiple hepatic interventions, including transjugular intrahepatic portosystemic shunts, liver transplantation, and hepatic disease in children. Lastly, we will discuss the path to clinical implementation and remaining challenges.

Establishment of a non-invasive prediction model for the risk of oesophageal variceal bleeding using radiomics based on CT

AIM

To establish a non-invasive prediction model for the risk of oesophageal variceal bleeding (OVB) using radiomics based on computed tomography (CT).

MATERIALS AND METHODS

The study included 317 patients, 69 of whom were OVB-positive and 248 were OVB-negative. The OVB was caused by cirrhosis associated with hepatitis B. All patients underwent both oesophagogastroduodenoscopy (OGD) and triple-phase contrast-enhanced CT with spectral imaging mode within 14 days before OGD. The patients were divided chronologically into training (n=222) and validation (n=95) cohorts at a ratio of 7:3. The clinical and CT features were collected from a picture archiving and communication system, and radiomics features were extracted from the portal venous phase CT. Spearman's correlation, least absolute shrinkage, and selection operator regression analyses were used to select the most correlated features. Models were built using the selected features. The predictive performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

One clinical feature, five CT features, and three radiomics features were selected, and three non-invasive models were built. Integration of the radiomics, CT, and clinical features model showed a better performance in predicting the risk of OVB, with an AUC of 0.89 (95% confidence interval [CI], 0.84-0.94) in the training dataset and 0.78 (95% CI, 0.68-0.87) in the validation dataset.

CONCLUSION

The combination of radiomics, CT, and clinical features may have added value in the non-invasive prediction of OVB, enabling early prevention and treatment.

Managing Recurrent Rectal Variceal Bleeding Secondary to Portal Hypertension With Liquid Embolics

Rectal variceal bleeding is one of the rarer manifestations of portal hypertension caused by chronic liver disease. The management of these varices is very challenging. Our patient had portal vein thrombosis and presented with chronic recurrent rectal bleeding requiring transfusion secondary to rectal varices. The patient was treated from trans-splenic access with liquid embolics (sclerotherapy and glue) without balloon occlusion, leading to the successful cessation of his bleeding. Access hemostasis was achieved using a vascular plug in the access tract. There are no clear guidelines for the management of these patients. If rectal varices cannot be managed by colonoscopy, this approach to embolization with liquid embolic is an excellent minimally invasive alternative.

Application of Magnetic Resonance Imaging in Liver Biomechanics: A Systematic Review

MRI-based biomechanical studies can provide a deep understanding of the mechanisms governing liver function, its mechanical performance but also liver diseases. In addition, comprehensive modeling of the liver can help improve liver disease treatment. Furthermore, such studies demonstrate the beginning of an engineering-level approach to how the liver disease affects material properties and liver function. Aimed at researchers in the field of MRI-based liver simulation, research articles pertinent to MRI-based liver modeling were identified, reviewed, and summarized systematically. Various MRI applications for liver biomechanics are highlighted, and the limitations of different viscoelastic models used in magnetic resonance elastography are addressed. The clinical application of the simulations and the diseases studied are also discussed. Based on the developed questionnaire, the papers' quality was assessed, and of the 46 reviewed papers, 32 papers were determined to be of high-quality. Due to the lack of the suitable material models for different liver diseases studied by magnetic resonance elastography, researchers may consider the effect of liver diseases on constitutive models. In the future, research groups may incorporate various aspects of machine learning (ML) into constitutive models and MRI data extraction to further refine the study methodology. Moreover, researchers should strive for further reproducibility and rigorous model validation and verification.

Quantification of the Hemodynamic Changes of Cirrhosis with Free-Breathing Self-Navigated MRI

BACKGROUND

Non-invasive assessment of the hemodynamic changes of cirrhosis might help guide management of patients with liver disease but are currently limited.

PURPOSE

To determine whether free-breathing 4D flow MRI can be used to quantify the hemodynamic effects of cirrhosis and introduce hydraulic circuit indexes of severity.

STUDY TYPE

Retrospective.

POPULATION

Forty-seven patients including 26 with cirrhosis.

FIELD STRENGTH/SEQUENCE

3 T/free-breathing 4D flow MRI with soft gating and golden-angle view ordering.

ASSESSMENT

Measurements of the supra-celiac abdominal aorta, supra-renal abdominal aorta (SRA), celiac trunk (CeT), superior mesenteric artery (SMA), splenic artery (SpA), common hepatic artery (CHA), portal vein (PV), and supra-renal inferior vena cava (IVC) were made by two radiologists. Measures of hepatic vascular resistance (hepatic arterial relative resistance [HARR]; portal resistive index [PRI]) were proposed and calculated.

STATISTICAL ANALYSIS

Bland-Altman, Pearson's correlation, Tukey's multiple comparison, and Cohen's kappa. P < 0.05 was considered significant.

RESULTS

Forty-four of 47 studies yielded adequate image quality for flow quantification (94%). Arterial structures showed high inter-reader concordance (range; ρ = 0.948-0.987) and the IVC (ρ = 0.972), with moderate concordance in the PV (ρ = 0.866). Conservation of mass analysis showed concordance between large vessels (SRA vs. IVC; ρ = 0.806), small vessels (celiac vs. CHA + SpA; ρ = 0.939), and across capillary beds (CeT + SMA vs. PV; ρ = 0.862). Splanchnic flow was increased in patients with portosystemic shunting (PSS) relative to control patients and patients with cirrhosis without PSS (P < 0.05, difference range 0.11-0.68 liter/m). HARR was elevated and PRI was decreased in patients with PSS (3.55 and 1.49, respectively) compared to both the control (2.11/3.18) and non-PSS (2.11/2.35) cohorts.

DATA CONCLUSION

4D flow MRI with self-navigation was technically feasible, showing promise in quantifying the hemodynamic effects of cirrhosis. Proposed quantitative metrics of hepatic vascular resistance correlated with PSS.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

Four-Dimensional Flow MRI of Abdominal Veins: A Systematic Review

The aim of this systematic review is to provide an overview of the use of Four-Dimensional Magnetic Resonance Imaging of vector blood flow (4D Flow MRI) in the abdominal veins. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in MEDLINE, Cochrane Library, EMBASE, and Web of Science. Quality assessment of the included studies was performed using the QUADAS-2 tool. The initial search yielded 781 studies and 21 studies were included. All studies successfully applied 4D Flow MRI in abdominal veins. Four-Dimensional Flow MRI was capable of discerning between healthy subjects and patients with cirrhosis and/or portal hypertension. The visual quality and inter-observer agreement of 4D Flow MRI were rated as excellent and good to excellent, respectively, and the studies utilized several different MRI data sampling strategies. By applying spiral sampling with compressed sensing to 4D Flow MRI, the blood flow of several abdominal veins could be imaged simultaneously in 18-25 s, without a significant loss of visual quality. Four-Dimensional Flow MRI might be a useful alternative to Doppler sonography for the diagnosis of cirrhosis and portal hypertension. Further clinical studies need to establish consensus regarding MRI sampling strategies in patients and healthy subjects.

Time-resolved 3D cine phase-contrast magnetic resonance imaging (4D-flow MRI) can quantitatively assess portosystemic shunt severity and confirm normalization of portal flow after embolization of large portosystemic shunts

Diagnosis and severity assessments of portosystemic shunts (PSSs) are important because the pathology sometimes results in severe hepatic encephalopathy, which can be treated almost completely by shunt embolization. At present, morphological assessment of PSS is performed mainly by computed tomography, and ultrasound is used for blood flow assessment. In two cases of PSS-related hepatic encephalopathy, we used time-resolved 3D cine phase-contrast (4D-flow) magnetic resonance imaging (MRI) to assess blood flow before and after shunt embolization. Before the intervention, blood flow in the main trunk of the superior mesenteric vein was mostly hepatofugal. However, post-interventional 4D-flow MRI revealed hepatopetal superior mesenteric vein flow with significantly increased portal vein blood flow. 4D-flow MRI is an ideal adjunct to Doppler ultrasonography, allowing for objective and visual assessment of morphology and blood flow of the portal venous system, including PSSs, and is useful in determining the indications for, and outcome of, PSS embolization.

Visualization of flow dynamics in the portal circulation using 320-detector-row computed tomography: a feasibility study

Multidetector row computed tomography (CT) scanners perform dynamic scanning and have a wide scan range. Time-resolved three-dimensional CT (i.e., 4D CT) has recently enabled visualization of flow in neurovascular vessels. We hypothesized that 4D CT technology would be a useful and non-invasive method for visualizing the flow dynamics of the portal circulation. The aim of this study was to evaluate the technical feasibility of 4D CT for visualizing flow dynamics in the portal circulation using 320-detector-row CT. 4D CT images of 18 consecutive patients with portal circulation including gastrorenal shunt were retrospectively evaluated for their ability to generate flow dynamics of the portal circulation. Flow dynamics could be visualized by 4D CT in 68 of the 72 vessels in the portal vein, splenic vein, superior mesenteric vein, and gastrorenal shunt. Flow direction could not be identified in four vessels, all of them being superior mesenteric veins. Flow direction was recognized on 4D CT in the 68 vessels of the portal circulation. A preliminary validation study revealed that flow direction of all 19 vessels in the portal circulation had concordance between 4D CT and color Doppler ultrasound. 4D CT could visualize flow dynamics of the portal circulation.

Abdominal Applications of 4D Flow MRI

BACKGROUND

 Four-dimensional flow magnetic resonance imaging (4D flow MRI) provides volumetric and time-resolved visualization and quantification of blood flow. This review presents an overview of possible applications of 4D flow MRI for non-invasive assessment of abdominal hemodynamics.

METHOD

 This review is based on the authors' experience and the current literature. A PubMed database literature research was performed in December 2019 focusing on abdominal applications of 4D flow MRI. We illustrated the review with exemplary figures and movies of clinical cases from our institution.

RESULTS AND CONCLUSION

 4D flow MRI offers the possibility of comprehensive assessment of abdominal blood flows in different vascular territories and organ systems. Results of recent studies indicate that 4D flow MRI improves understanding of altered hemodynamics in patients with abdominal disease and may be useful for monitoring therapeutic response. Future studies with larger cohorts aiming to integrate 4D flow MRI in the clinical routine setting are needed.

KEY POINTS

  · 4D flow MRI enables comprehensive visualization of the complex abdominal vasculature. · 4D flow MRI enables quantification of abdominal blood flow velocities and flow rates. · 4D flow MRI may enable deeper understanding of altered hemodynamics in abdominal disease. · Further validation studies are needed prior to broad distribution of abdominal 4D flow MRI.

CITATION FORMAT

· Riedel C, Lenz A, Fischer L et al. Abdominal Applications of 4D Flow MRI. Fortschr Röntgenstr 2021; 193: 388 - 398.

Noninvasive imaging assessment of portal hypertension

Portal hypertension (PH) is a spectrum of complications of chronic liver disease (CLD) and cirrhosis, with manifestations including ascites, gastroesophageal varices, splenomegaly, hypersplenism, hepatic hydrothorax, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. PH can vary in severity and is diagnosed via invasive hepatic venous pressure gradient measurement (HVPG), which is considered the reference standard. Accurate diagnosis of PH and assessment of severity are highly relevant as patients with clinically significant portal hypertension (CSPH) are at higher risk for developing acute variceal bleeding and mortality. In this review, we discuss current and upcoming noninvasive imaging methods for diagnosis and assessment of severity of PH.

Imaging biomarkers of diffuse liver disease: current status

We are happy to introduce this special issue of Abdominal Radiology on "diffuse liver disease". We have invited imaging experts to discuss various topics pertaining to diffuse liver disease, covering a vast array of imaging techniques including ultrasound (US), CT, MRI and new molecular imaging agents. Below, we briefly discussed the current status, limitations, and future directions of imaging biomarkers of diffuse liver disease.

Portal Vein Stenosis Following Liver Transplantation Hemodynamically Assessed with 4D-flow MRI before and after Portal Vein Stenting

We present a case of a patient who underwent portal vein (PV) stenting for PV stenosis after a living-donor liver transplantation. A pretreatment 3D cine phase-contrast (4D-flow) MRI showed decreased, though hepatopetal, blood flow in the PV. After stenting, 4D-flow MRI confirmed an improvement in PV flow, with a more homogeneous flow distribution to each hepatic segment. 4D-flow MRI are valuable for understanding the hemodynamics of this area, planning for treatments, and evaluating the outcome of the interventions.

Noninvasive Diagnostics for Portal Hypertension: A Comprehensive Review

Noninvasive diagnostics for portal hypertension include imaging and functional tests, as well as blood-based biomarkers, and capture different features of the portal hypertensive syndrome. Definitive conclusions regarding their clinical utility require assessment of their diagnostic value in specific clinical settings (i.e., diagnosing a particular hemodynamic condition within a well-defined target population). Several noninvasive methods are predictive of clinically significant portal hypertension (CSPH; hepatic venous pressure gradient [HVPG] ≥ 10 mm Hg; the threshold for complications of portal hypertension); however, only a minority of them have been evaluated in compensated advanced chronic liver disease (i.e., the target population). Importantly, most methods correlate only weakly with HVPG at high values (i.e., in patients with CSPH). Nevertheless, selected methods show promise for diagnosing HVPG ≥ 16 mm Hg (the cut-off for increased risks of hepatic decompensation and mortality) and monitoring HVPG changes in response to nonselective beta-blockers or etiological treatments. Finally, we review established and potential future clinical applications of noninvasive methods.

Performance of liver surface nodularity quantification for the diagnosis of portal hypertension in patients with cirrhosis: comparison between MRI with hepatobiliary phase sequences and CT

PURPOSE

To assess and compare the performance of liver surface nodularity (LSN) quantification using Gd-BOPTA-enhanced MRI and contrast-enhanced CT for the diagnosis of clinically significant portal hypertension (CSPH) in patients with cirrhosis.

METHODS

This retrospective study included 30 patients with compensated histologically proven cirrhosis who underwent hepatic venous pressure gradient (HVPG), abdominal CT and Gd-BOPTA-MRI within a 60-day interval during pre-surgery workup for hepatocellular carcinoma (HCC) between January 2016 and August 2018. LSN score was derived from CT portal venous phase (PVP), axial T2- and T1-weighted PVP and hepatobiliary phase (HBP). Accuracy for the detection of CSPH was evaluated for each set of images by ROC curve analysis. Intra-observer, inter-observer and inter-method reproducibilities were assessed by the intraclass correlation coefficient (ICC) and coefficient of variation (CV).

RESULTS

Thirty patients were analysed (23 men [77%], mean age 60 ± 11 years old), including 15 (50%) with CSPH. All CT- and MRI-derived LSN quantifications were correlated to HVPG (CT-PVP: r = 0.63, p = 0.001, AUROC = 0.908 ± 0.06; T1-w-PVP: r = 0.43, p = 0.028, AUROC = 0.876 ± 0.07; T1-w-HBP: r = 0.50, p = 0.012, AUROC = 0.823 ± 0.08; T2-w: r = 0.51, p = 0.007, AUROC = 0.801 ± 0.09). There was no significant difference in AUROC pairwise comparisons (p = 0.12-0.88). Patients with CSPH had higher LSN than those without (CT-PVP: 3.2 ± 0.6 vs 2.4 ± 0.5, p < 0.001; T1-w-PVP: 2.7 ± 0.4 vs 2.2 ± 0.4, p = 0.002; T1-w-HBP: 3.0 ± 0.6 vs 2.3 ± 0.3, p < 0.001; T2-w: 3.0 ± 0.6 vs 2.2 ± 0.3, p = 0.001) and 86%, 82%, 85% and 82% of patients were correctly classified, respectively. Reproducibility of inter-image set comparisons was excellent (ICC = 0.84-0.96 and CV = 8.3-14.2%).

CONCLUSION

The diagnostic performance of MRI-based LSN for detecting CSPH is strong and similar to that of CT-based LSN.