RÉSUMÉ
BACKGROUND: Time-resolved, three-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) plays an important role in assessing cardiovascular diseases. However, the manual or semi-automatic segmentation of aortic vessel boundaries in 4D flow data introduces variability and limits reproducibility of aortic hemodynamics visualization and quantitative flow-related parameter computation. This paper explores the potential of deep learning to improve 4D flow MRI segmentation by developing models for automatic segmentation and analyzes the impact of the training data on the generalization of the model across different sites, scanner vendors, sequences, and pathologies. METHODS: The study population consists of 260 4D flow MRI datasets, including subjects without known aortic pathology, healthy volunteers, and patients with bicuspid aortic valve (BAV) examined at different hospitals. The dataset was split to train segmentation models on subsets with different representations of characteristics such as pathology, gender, age, scanner model, vendor, and field strength. An enhanced 3D U-net convolutional neural network (CNN) architecture with residual units was trained for 2D+t aortic cross-sectional segmentation. The model performance was evaluated using Dice score, Hausdorff distance, and average symmetric surface distance on test data, datasets with characteristics not represented in the training set (model-specific), and an overall evaluation set. Standard diagnostic flow parameters were computed and compared with manual segmentation results using Bland-Altman analysis and interclass correlation. RESULTS: The representation of technical factors such as scanner vendor and field strength in the training dataset had the strongest influence on the overall segmentation performance. Age had a greater impact than gender. Models solely trained on BAV patients' datasets performed well on datasets of healthy subjects but not vice versa. CONCLUSION: This study highlights the importance of considering a heterogeneous dataset for the training of widely applicable automatic CNN segmentations in 4D flow MRI, with a particular focus on the inclusion of different pathologies and technical aspects of data acquisition.
RÉSUMÉ
Investigation of motivation and identification of success factors in radiology research in Germany.Using a German online survey (54 questions, period: 3.5 months), demographic aspects, intrinsic and extrinsic success characteristics, as well as personal and organizational success factors were surveyed based on a career success model. The survey results were reported descriptively. The correlations between success factors and success characteristics were examined using linear, binary-logistic, and multinomial regression models.176 people (164 academically active, 10 not academically active) answered the survey. Most participants (80%, 139/174) worked at a university hospital. 32% had privatdozent or professor as their highest academic title (56/173). The researchers' main motivation was intrinsic interest in research (55%, 89/163), followed by a desire to increase their own career opportunities (25%, 41/163). The following were identified as factors for intrinsic success: i) support from department management (estimate=ß=0.26, p<0.001), ii) good work-life balance (ß=0.37, p<0.001), and iii) the willingness to pursue science even after reaching the career goal (ß=0.16, p<0.016). Relevant factors for extrinsic scientific success were mentoring, protected research time, and activities in professional societies.Researchers in German radiology are mainly intrinsically motivated. Factors known from the literature that determine intrinsic and extrinsic scientific success were confirmed in this study. Knowledge of these factors allows targeted systematic support and could thus increase scientific success in German radiology. · Main motivation for German radiology research is intrinsic interest, followed by career opportunities.. · Factors for intrinsic scientific success are good work-life balance and support by department management.. · Factors for extrinsic scientific success are mentoring, activities in professional societies, and protected research time.. · Wegner F, Heinrichs H, Stahlmann K et al. Motivation and success factors in radiological research in Germany - results of a survey by the Methodology and Research Working Group of the German Radiological Society. Fortschr Röntgenstr 2024; DOI 10.1055/a-2350-0023.
RÉSUMÉ
Due to their exceptional solubility and stability, nanobodies have emerged as powerful building blocks for research tools and therapeutics. However, their generation in llamas is cumbersome and costly. Here, by inserting an engineered llama immunoglobulin heavy chain (IgH) locus into IgH-deficient mice, we generate a transgenic mouse line, which we refer to as 'LamaMouse'. We demonstrate that LamaMice solely express llama IgH molecules without association to Igκ or λ light chains. Immunization of LamaMice with AAV8, the receptor-binding domain of the SARS-CoV-2 spike protein, IgE, IgG2c, and CLEC9A enabled us to readily select respective target-specific nanobodies using classical hybridoma and phage display technologies, single B cell screening, and direct cloning of the nanobody-repertoire into a mammalian expression vector. Our work shows that the LamaMouse represents a flexible and broadly applicable platform for a facilitated selection of target-specific nanobodies.
Sujet(s)
Camélidés du Nouveau Monde , Chaines lourdes des immunoglobulines , Souris transgéniques , Anticorps à domaine unique , Glycoprotéine de spicule des coronavirus , Animaux , Anticorps à domaine unique/génétique , Anticorps à domaine unique/immunologie , Camélidés du Nouveau Monde/immunologie , Chaines lourdes des immunoglobulines/génétique , Chaines lourdes des immunoglobulines/immunologie , Souris , Glycoprotéine de spicule des coronavirus/immunologie , Glycoprotéine de spicule des coronavirus/génétique , Glycoprotéine de spicule des coronavirus/composition chimique , Lectines de type C/métabolisme , Lectines de type C/immunologie , Lectines de type C/génétique , SARS-CoV-2/immunologie , SARS-CoV-2/génétique , Immunoglobuline E/immunologie , Humains , Dependovirus/génétique , Dependovirus/immunologie , Immunoglobuline G/immunologie , COVID-19/immunologie , Lymphocytes B/immunologieRÉSUMÉ
In this paper, we explain the structure and function of different types of figures and provide guidance on how to create effective figures for radiological research publications.Based on scientific literature and our own experience, we have compiled a series of instructions to support the purposeful creation of effective figures for radiological research publications.Effective figures play a crucial role in radiological research publications by clearly visualizing complex content and thereby enhancing its comprehensibility. Different types of figures have distinct strengths that should be strategically employed for optimal impact. The interplay between figures weaves the "common thread" of a publication, facilitating reader comprehension and providing a straightforward path to the answer of the central research question. The systematic coordination (line of evidence) and effective design of individual figures are crucial to compellingly support the publication's central hypothesis.The deliberate creation and coordination of figures in radiological research publications are decisive factors for successful publishing. · Different types of figures have distinct strengths that should be strategically employed for optimal impact.. · The interplay between figures weaves the "common thread" of a publication, facilitating reader comprehension and providing a straightforward path to the answer of the central research question.. · The appropriate coordination of different types of figures enables an effective and precise presentation of the research findings.. · The systematic coordination (line of evidence) and effective design of individual figures are crucial to compellingly support the publication's central hypothesis.. · The deliberate creation and coordination of figures in radiological research publications are decisive factors for successful publishing.. · Pape LJ, Hambach J, Bannas P. Instructions for figures in radiological research publications. Fortschr Röntgenstr 2024; DOI 10.1055/a-2285-3223.
RÉSUMÉ
OBJECTIVES: To compare the feasibility and reliability of manual versus software-assisted assessments of computed tomography scans according to iRECIST in patients undergoing immune-based cancer treatment. METHODS: Computed tomography scans of 30 tumor patients undergoing cancer treatment were evaluated by four independent radiologists at baseline (BL) and two follow-ups (FU), resulting in a total of 360 tumor assessments (120 each at BL/FU1/FU2). After image interpretation, tumor burden and response status were either calculated manually or semi-automatically as defined by software, respectively. The reading time, calculated sum of longest diameter (SLD), and tumor response (e.g., "iStable Disease") were determined for each assessment. After complete data collection, a consensus reading among the four readers was performed to establish a reference standard for the correct response assignments. The reading times, error rates, and inter-reader agreement on SLDs were statistically compared between the manual versus software-assisted approaches. RESULTS: The reading time was significantly longer for the manual versus software-assisted assessments at both follow-ups (median [interquartile range] FU1: 4.00 min [2.17 min] vs. 2.50 min [1.00 min]; FU2: 3.75 min [1.88 min] vs. 2.00 min [1.50 min]; both p < 0.001). Regarding reliability, 2.5% of all the response assessments were incorrect at FU1 (3.3% manual; 0% software-assisted), which increased to 5.8% at FU2 (10% manual; 1.7% software-assisted), demonstrating higher error rates for manual readings. Quantitative SLD inter-reader agreement was inferior for the manual compared to the software-assisted assessments at both FUs (FU1: ICC = 0.91 vs. 0.93; FU2: ICC = 0.75 vs. 0.86). CONCLUSIONS: Software-assisted assessments may facilitate the iRECIST response evaluation of cancer patients in clinical routine by decreasing the reading time and reducing response misclassifications.
RÉSUMÉ
Background: Neurofibromatosis type 1 (NF1) is associated with the development of benign (BPNST) and malignant (MPNST) peripheral nerve sheath tumors. Recently described atypical neurofibromas (ANF) are considered pre-malignant precursor lesions to MPNSTs. Previous studies indicate that diffusion-weighted magnetic resonance imaging (DW-MRI) can reliably discriminate MPNSTs from BPNSTs. We therefore investigated the diagnostic accuracy of DW-MRI for the discrimination of benign, atypical, and malignant peripheral nerve sheath tumors. Methods: In this prospective explorative single-center phase II diagnostic study, 44 NF1 patients (23 male; 30.1â ±â 11.8 years) underwent DW-MRI (b-values 0-800 s/mm²) at 3T. Two radiologists independently assessed mean and minimum apparent diffusion coefficients (ADCmean/min) in areas of largest tumor diameters and ADCdark in areas of lowest signal intensity by manual contouring of the tumor margins of 60 BPNSTs, 13 ANFs, and 21 MPNSTs. Follow-up of ≥â 24 months (BPNSTs) or histopathological evaluation (ANFsâ +â MPNSTs) served as diagnostic reference standard. Diagnostic ADC-based cut-off values for discrimination of the three tumor groups were chosen to yield the highest possible specificity while maintaining a clinically acceptable sensitivity. Results: ADC values of pre-malignant ANFs clustered between BPNSTs and MPNSTs. Best BPNST vs. ANFâ +â MPNST discrimination was obtained using ADCdark at a cut-off value of 1.6â ×â 10-3 mm2/s (85.3% sensitivity, 93.3% specificity), corresponding to an AUC of 94.3% (95% confidence interval: 85.2-98.0). Regarding BPNSTâ +â ANF vs. MPNST, best discrimination was obtained using an ADCdark cut-off value of 1.4â ×â 10-3 mm2/s (83.3% sensitivity, 94.5% specificity). Conclusions: DW-MRI using ADCdark allows specific and noninvasive discrimination of benign, atypical, and malignant nerve sheath tumors in NF1.
RÉSUMÉ
(1) Background: Accurate hepatic artery (HA) depiction following pediatric liver transplantation (LT) is essential for graft surveillance but challenging on ultrasound (US). This study assesses if improved HA delineation can be achieved by recording two-dimensional US volumes in Color Doppler (CD) and B-flow technique. (2) Methods: Of 42 consecutive LT, 37 cases were included, and HA delineation was retrospectively rated using a four-point score (0 = HA not detectable, 3 = HA fully detectable, separable from portal vein) within 48 h post-LT (U1) and before discharge (U2). (3) Results: Adding B-flow compared with CD alone showed superior results at neohilar (U1: 2.2 ± 1.0 vs. 1.1 ± 0.8, p < 0.0001; U2: 2.5 ± 0.8 vs. 1.5 ± 0.9, p < 0.0001) and segmental levels (U1: 2.8 ± 0.6 vs. 0.6 ± 0.8, p < 0.0001; U2: 2.8 ± 0.6 vs. 0.7 ± 0.5, p < 0.0001). (4) Conclusions: Standardized US volume recordings combining B-flow and CD can effectively delineate the HA along its vascular course in pediatric LT. The technique should be further evaluated as a standard monitoring instrument to rule out vascular complications after LT.
RÉSUMÉ
Cardiac MRI is a crucial tool for assessing congenital heart disease (CHD). However, its application remains challenging in young children when performed at 3T. The aim of this retrospective single center study was to compare a non-contrast free-breathing 2D CINE T1-weighted TFE-sequence with compressed sensing (FB 2D CINE CS T1-TFE) with 3D imaging for diagnostic accuracy of CHD, image quality, and vessel diameter measurements in sedated young children. FB 2D CINE CS T1-TFE was compared with a 3D non-contrast whole-heart sequence (3D WH) and 3D contrast-enhanced MR angiography (3D CE-MRA) at 3T in 37 CHD patients (20â, 1.5±1.4 years). Two radiologists independently assessed image quality, type of CHD, and diagnostic confidence. Diameters and measures of contrast and sharpness of the aorta and pulmonary vessels were determined. A non-parametric multi-factorial approach was used to estimate diagnostic accuracy for the diagnosis of CHD. Linear mixed models were calculated to compare contrast and vessel sharpness. Krippendorff's alpha was determined to quantify vessel diameter agreement. FB 2D CINE CS T1-TFE was rated superior regarding image quality, diagnostic confidence, and diagnostic sensitivity for both intra- and extracardiac pathologies compared to 3D WH and 3D CE-MRA (all p<0.05). FB 2D CINE CS T1-TFE showed superior contrast and vessel sharpness (p<0.001) resulting in the highest proportion of measurable vessels (740/740; 100%), compared to 3D WH (530/620; 85.5%) and 3D CE-MRA (540/560; 96.4%). Regarding vessel diameter measurements, FB 2D CINE CS T1-TFE revealed the closest inter-reader agreement (Krippendorff's alpha: 0.94-0.96; 3D WH: 0.78-0.94; 3D CE-MRA: 0.76-0.93). FB 2D CINE CS T1-TFE demonstrates robustness at 3T and delivers high-quality diagnostic results to assess CHD in sedated young children. Its ability to function without contrast injection and respiratory compensation enhances ease of use and could encourage widespread adoption in clinical practice.
Sujet(s)
Produits de contraste , Cardiopathies congénitales , Enfant , Humains , Enfant d'âge préscolaire , Études rétrospectives , Imagerie tridimensionnelle/méthodes , Cardiopathies congénitales/imagerie diagnostique , Imagerie par résonance magnétique , Angiographie par résonance magnétique/méthodes , Reproductibilité des résultatsRÉSUMÉ
OBJECTIVES: Assessment of myocardial strain by feature tracking magnetic resonance imaging (FT-MRI) in human fetuses with and without congenital heart disease (CHD) using cardiac Doppler ultrasound (DUS) gating. METHODS: A total of 43 human fetuses (gestational age 28-41 weeks) underwent dynamic cardiac MRI at 3 T. Cine balanced steady-state free-precession imaging was performed using fetal cardiac DUS gating. FT-MRI was analyzed using dedicated post-processing software. Endo- and epicardial contours were manually delineated from fetal cardiac 4-chamber views, followed by automated propagation to calculate global longitudinal strain (GLS) of the left (LV) and right ventricle (RV), LV radial strain, and LV strain rate. RESULTS: Strain assessment was successful in 38/43 fetuses (88%); 23 of them had postnatally confirmed diagnosis of CHD (e.g., coarctation, transposition of great arteries) and 15 were heart healthy. Five fetuses were excluded due to reduced image quality. In fetuses with CHD compared to healthy controls, median LV GLS (- 13.2% vs. - 18.9%; p < 0.007), RV GLS (- 7.9% vs. - 16.2%; p < 0.006), and LV strain rate (1.4 s-1 vs. 1.6 s-1; p < 0.003) were significantly higher (i.e., less negative). LV radial strain was without a statistically significant difference (20.7% vs. 22.6%; p = 0.1). Bivariate discriminant analysis for LV GLS and RV GLS revealed a sensitivity of 67% and specificity of 93% to differentiate between fetuses with CHD and healthy fetuses. CONCLUSION: Myocardial strain was successfully assessed in the human fetus, performing dynamic fetal cardiac MRI with DUS gating. Our study indicates that strain parameters may allow for differentiation between fetuses with and without CHD. CLINICAL RELEVANCE STATEMENT: Myocardial strain analysis by cardiac MRI with Doppler ultrasound gating and feature tracking may provide a new diagnostic approach for evaluation of fetal cardiac function in congenital heart disease. KEY POINTS: ⢠MRI myocardial strain analysis has not been performed in human fetuses so far. ⢠Myocardial strain was assessed in human fetuses using cardiac MRI with Doppler ultrasound gating. ⢠MRI myocardial strain may provide a new diagnostic approach to evaluate fetal cardiac function.
Sujet(s)
Coeur foetal , Cardiopathies congénitales , Humains , Femelle , Grossesse , Cardiopathies congénitales/imagerie diagnostique , Coeur foetal/imagerie diagnostique , IRM dynamique/méthodes , Imagerie par résonance magnétique/méthodes , Techniques d'imagerie cardiaque synchronisée/méthodesRÉSUMÉ
BACKGROUND: An abdominal aortic aneurysm (AAA) is defined as a localized dilatation of the abdominal aorta of ≥â3âcm. With a prevalence of 4-8â%, 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.âg., using 4D flow MRI.
Sujet(s)
Anévrysme de l'aorte abdominale , Humains , Anévrysme de l'aorte abdominale/imagerie diagnostique , Anévrysme de l'aorte abdominale/chirurgie , Aorte abdominale/imagerie diagnostique , Échographie/méthodes , Angiographie par tomodensitométrie , Imagerie par résonance magnétiqueRÉSUMÉ
BACKGROUND AND PURPOSE: Thalamic hypometabolism is a consistent finding in brain PET with F-18 fluorodeoxyglucose (FDG) in patients with neurofibromatosis type 1 (NF1). However, the pathophysiology of this metabolic alteration is unknown. We hypothesized that it might be secondary to disturbance of peripheral input to the thalamus by NF1-characteristic peripheral nerve sheath tumors (PNSTs). To test this hypothesis, we investigated the relationship between thalamic FDG uptake and the number, volume, and localization of PNSTs. METHODS: This retrospective study included 22 adult NF1 patients (41% women, 36.2 ± 13.0 years) referred to whole-body FDG-PET/contrast-enhanced CT for suspected malignant transformation of PNSTs and 22 sex- and age-matched controls. Brain FDG uptake was scaled voxelwise to the individual median uptake in cerebellar gray matter. Bilateral mean and left-right asymmetry of thalamic FDG uptake were determined using a left-right symmetric anatomical thalamus mask. PNSTs were manually segmented in contrast-enhanced CT. RESULTS: Thalamic FDG uptake was reduced in NF1 patients by 2.0 standard deviations (p < .0005) compared to controls. Left-right asymmetry was increased by 1.3 standard deviations (p = .013). Thalamic hypometabolism was higher in NF1 patients with ≥3 PNSTs than in patients with ≤2 PNSTs (2.6 vs. 1.6 standard deviations, p = .032). The impact of the occurrence of paraspinal/paravertebral PNSTs and of the mean PNST volume on thalamic FDG uptake did not reach statistical significance (p = .098 and p = .189). Left-right asymmetry of thalamic FDG uptake was not associated with left-right asymmetry of PNST burden (p = .658). CONCLUSIONS: This study provides first evidence of left-right asymmetry of thalamic hypometabolism in NF1 and that it might be mediated by NF1-associated peripheral tumors.
Sujet(s)
Tumeurs des gaines nerveuses , Neurofibromatose de type 1 , Adulte , Humains , Femelle , Mâle , Tomographie par émission de positons couplée à la tomodensitométrie , Fluorodésoxyglucose F18/métabolisme , Neurofibromatose de type 1/complications , Neurofibromatose de type 1/imagerie diagnostique , Neurofibromatose de type 1/métabolisme , Études rétrospectives , Charge tumorale , Tomographie par émission de positons/méthodes , Tumeurs des gaines nerveuses/complications , Tumeurs des gaines nerveuses/métabolisme , Tumeurs des gaines nerveuses/anatomopathologie , Thalamus/imagerie diagnostique , Thalamus/anatomopathologieRÉSUMÉ
BACKGROUND: Imaging biomarkers are quantitative parameters from imaging modalities, which are collected noninvasively, allow conclusions about physiological and pathophysiological processes, and may consist of single (monoparametric) or multiple parameters (bi- or multiparametric). METHOD: This review aims to present the state of the art for the quantification of multimodal and multiparametric imaging biomarkers. Here, the use of biomarkers using artificial intelligence will be addressed and the clinical application of imaging biomarkers in breast and prostate cancers will be explained. For the preparation of the review article, an extensive literature search was performed based on Pubmed, Web of Science and Google Scholar. The results were evaluated and discussed for consistency and generality. RESULTS AND CONCLUSION: Different imaging biomarkers (multiparametric) are quantified based on the use of complementary imaging modalities (multimodal) from radiology, nuclear medicine, or hybrid imaging. From these techniques, parameters are determined at the morphological (e.âg., size), functional (e.âg., vascularization or diffusion), metabolic (e.âg., glucose metabolism), or molecular (e.âg., expression of prostate specific membrane antigen, PSMA) level. The integration and weighting of imaging biomarkers are increasingly being performed with artificial intelligence, using machine learning algorithms. In this way, the clinical application of imaging biomarkers is increasing, as illustrated by the diagnosis of breast and prostate cancers. KEY POINTS: · Imaging biomarkers are quantitative parameters to detect physiological and pathophysiological processes.. · Imaging biomarkers from multimodality and multiparametric imaging are integrated using artificial intelligence algorithms.. · Quantitative imaging parameters are a fundamental component of diagnostics for all tumor entities, such as for mammary and prostate carcinomas.. CITATION FORMAT: · Bäuerle T, Dietzel M, Pinker K etâal. Identification of impactful imaging biomarker: Clinical applications for breast and prostate carcinoma. Fortschr Röntgenstr 2024; 196: 354â-â362.
Sujet(s)
Carcinomes , Médecine nucléaire , Tumeurs de la prostate , Humains , Mâle , Intelligence artificielle , Marqueurs biologiques , Imagerie par résonance magnétique/méthodes , Prostate/imagerie diagnostique , Prostate/anatomopathologie , Tumeurs de la prostate/imagerie diagnostique , Tumeurs de la prostate/anatomopathologie , FemelleRÉSUMÉ
Background & Aims: Cirrhosis is associated with an increased surgical morbidity and mortality. Portal hypertension and the surgery type have been established as critical determinants of postoperative outcome. We aim to evaluate the hypothesis that preoperative transjugular intrahepatic portosystemic shunt (TIPS) placement in patients with cirrhosis is associated with a lower incidence of in-house mortality/liver transplantation (LT) after surgery. Methods: A retrospective database search for the years 2010-2020 was carried out. We identified 64 patients with cirrhosis who underwent surgery within 3 months after TIPS placement and 131 patients with cirrhosis who underwent surgery without it (controls). Operations were categorised into low-risk and high-risk procedures. The primary endpoint was in-house mortality/LT. We analysed the influence of high-risk surgery, preoperative TIPS placement, age, sex, baseline creatinine, presence of ascites, Chronic Liver Failure Consortium Acute Decompensation (CLIF-C AD), American Society of Anesthesiologists (ASA), and model for end-stage liver disease (MELD) scores on in-house mortality/LT by multivariable Cox proportional hazards regression. Results: In both the TIPS and the control cohort, most patients presented with a Child-Pugh B stage (37/64, 58% vs. 70/131, 53%) at the time of surgery, but the median MELD score was higher in the TIPS cohort (14 vs. 11 points). Low-risk and high-risk procedures amounted to 47% and 53% in both cohorts. The incidence of in-house mortality/LT was lower in the TIPS cohort (12/64, 19% vs. 52/131, 40%), also when further subdivided into low-risk (0/30, 0% vs. 10/61, 16%) and high-risk surgery (12/34, 35% vs. 42/70, 60%). Preoperative TIPS placement was associated with a lower rate for postoperative in-house mortality/LT (hazard ratio 0.44, 95% CI 0.19-1.00) on multivariable analysis. Conclusions: A preoperative TIPS might be associated with reduced postoperative in-house mortality in selected patients with cirrhosis. Impact and implications: Patients with cirrhosis are at risk for more complications and a higher mortality after surgical procedures. A transjugular intrahepatic portosystemic shunt (TIPS) is used to treat complications of cirrhosis, but it is unclear if it also helps to lower the risk of surgery. This study takes a look at complications and mortality of patients undergoing surgery with or without a TIPS, and we found that patients with a TIPS develop less complications and have an improved survival. Therefore, a preoperative TIPS should be considered in selected patients, especially if indicated by ascites.
RÉSUMÉ
Background: To assess whether cardiac T1 mapping for detecting myocardial fibrosis enables preoperative identification of patients at risk for early left ventricular dysfunction after surgery of aortic regurgitation. Methods: 1.5 Tesla cardiac magnetic resonance imaging was performed in 40 consecutive aortic regurgitation patients before aortic valve surgery. Native and post-contrast T1 mapping was performed using a modified Look-Locker inversion-recovery sequence. Serial echocardiography was performed at baseline and 8 ± 5 days after aortic valve surgery to quantify LV dysfunction. Receiver operating characteristic analysis was performed to determine the diagnostic accuracy of native T1 mapping and extracellular volume for predicting postoperative LV ejection fraction decrease >-10% after aortic valve surgery. Results: Native T1 was significantly increased in patients with a postoperatively decreased LVEF (n = 15) vs. patients with a preserved postoperative LV ejection fraction (n = 25) (i.e., 1,071 ± 67â ms vs. 1,019 ± 33â ms, p = .001). Extracellular volume was not significantly different between patients with preserved vs. decreased postoperative LV ejection fraction. With a cutoff-of value of 1,053â ms, native T1 yielded an area under the curve (AUC) of .820 (95% CI: .683-.958) for differentiating between patients with preserved vs. reduced LV ejection fraction with 70% sensitivity and 84% specificity. Conclusion: Increased preoperative native T1 is associated with a significantly higher risk of systolic LV dysfunction early after aortic valve surgery in aortic regurgitation patients. Native T1 could be a promising tool to optimize the timing of aortic valve surgery in patients with aortic regurgitation to prevent early postoperative LV dysfunction.
RÉSUMÉ
OBJECTIVES: To define and compare growth rates of the distal aorta in Marfan patients with and without aortic root replacement using serial MR angiography (MRA). METHODS: We retrospectively included 136 Marfan patients with a total of 645 MRAs who underwent a median of five MRAs (range: 2-13) at 1.5 T and 3 T in annual intervals. Of these, 41 patients (34.8 ± 12 years) had undergone aortic root replacement. The remaining 95 patients (29.0 ± 17 years) still had a native aorta and served as the control group. Thoracic aortic diameters were independently measured at eleven predefined levels. Estimated growth rates were calculated using a mixed effects model adjusted for sex, age, BMI, and medication. RESULTS: Marfan patients with aortic root replacement revealed the highest mean estimated growth rate in the proximal descending aorta (0.77 mm/year, CI: 0.31-1.21). Mean growth rates at all levels of the distal thoracic aorta were significantly higher in patients with aortic root replacement (0.28-0.77 mm/year) when compared to patients without aortic root replacement (0.03-0.07 mm/year) (all p < 0.001). Antihypertensive medication, gender, and BMI had no significant impact on the distal aortic growth rates. CONCLUSION: Distal thoracic aortic diameters increase at a significantly higher rate in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. Further studies are warranted to investigate if the increased growth rate of the distal thoracic aorta after aortic root replacement is caused by altered hemodynamics due to the rigid aortic root graft or due to the general genetic disposition of post-operative Marfan patients. CLINICAL RELEVANCE STATEMENT: High growth rates of the distal aorta after aortic root replacement underline the need for careful life-long aortic imaging of Marfan patients after aortic root replacement. KEY POINTS: ⢠Aortic growth rates in Marfan patients with aortic root replacement are highest in the mid-aortic arch, the proximal- and mid-descending aorta. ⢠Growth rates of the distal thoracic aorta are significantly higher in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. ⢠Antihypertensive medication, gender, and BMI have no significant impact on distal aortic growth rates in Marfan patients.
Sujet(s)
Anévrysme de l'aorte thoracique , Syndrome de Marfan , Humains , Syndrome de Marfan/complications , Syndrome de Marfan/chirurgie , Études de suivi , Études rétrospectives , Valve aortique , Antihypertenseurs , Dilatation , Aorte/imagerie diagnostique , Aorte/chirurgie , Aorte thoracique/imagerie diagnostique , Aorte thoracique/chirurgie , Angiographie , Dilatation pathologique , Anévrysme de l'aorte thoracique/chirurgieRÉSUMÉ
Our objective was to compare the ability to detect histopathologically confirmed lymph node metastases by early and delayed [99mTc]Tc-PSMA-I&S SPECT/CT in early biochemically recurrent prostate cancer. Methods: We retrospectively analyzed 222 patients selected for radioguided surgery using [99mTc]Tc-PSMA-I&S SPECT/CT at different time points after injection (≤4 h and >15 h). In total, 386 prostate-specific membrane antigen (PSMA) PET predetermined lesions were analyzed on SPECT/CT using a 4-point scale, and the results were compared between early and late imaging groups, with uni- and multivariate analyses performed including prostate-specific antigen, injected [99mTc]Tc-PSMA-I&S activity, Gleason grade group, initial TNM stage, and, stratified by size, PSMA PET/CT-positive lymph nodes. PSMA PET/CT findings served as the standard of reference. Results: [99mTc]Tc-PSMA-I&S SPECT/CT had a significantly higher positivity rate for detecting lesions in the late than the early imaging group (79%, n = 140/178, vs. 27%, n = 12/44 [P < 0.05] on a patient basis; 60%, n = 195/324, vs. 21%, n = 13/62 [P < 0.05] on a lesion basis). Similar positivity rates were found when lesions were stratified by size. Multivariate analysis found that SUVmax on PSMA PET/CT and the uptake time of [99mTc]Tc-PSMA-I&S were independent predictors for lesion detectability on SPECT/CT. Conclusion: Late imaging (>15 h after injection) should be preferred when [99mTc]Tc-PSMA-I&S SPECT/CT is used for lesion detection in early biochemical recurrence of prostate cancer. However, the performance of PSMA SPECT/CT is clearly inferior to that of PSMA PET/CT.
Sujet(s)
Prostate , Tumeurs de la prostate , Mâle , Humains , Prostate/anatomopathologie , Tomographie par émission de positons couplée à la tomodensitométrie/méthodes , Études rétrospectives , Récidive tumorale locale , Tumeurs de la prostate/anatomopathologie , Tomographie par émission monophotonique couplée à la tomodensitométrie , Radio-isotopes du galliumRÉSUMÉ
Myocardial native T1 is a known cardiovascular magnetic resonance (CMR) imaging biomarker to quantify diffuse myocardial fibrosis in valvular cardiomyopathy. We hypothesized that diffuse myocardial fibrosis assessed by preoperative T1 mapping might correlate with LV reverse remodeling after valvular surgery. A prospective monocentric cohort study was conducted including 79 consecutive patients with valvular cardiomyopathy referred for surgical treatment of severe aortic or severe functional mitral regurgitation. Native T1 values were assessed by CMR before surgery. LV geometry parameters (i.e., LVEDV, LVESV) were obtained by 2D transthoracic echocardiography before and six months after surgery. Postoperative change of LV geometry parameters was calculated as delta (∆) variable (i.e., six months value minus baseline value). Mean native T1 was 1047 ± 39 ms, mean ∆LVEDV was -33 ± 42 mL, and mean ∆LVESV was -15 ± 27 mL. Native T1 values correlated with ∆LVEDV (Pearson r = 0.29; p = 0.009) and ∆LVESV (Pearson r = 0.29; p = 0.015). Native T1 values < 1073 ms were identified as independent predictor of postoperative reduction of LVEDV (HR 3.0; 95%-CI: 1.1-8.0; p = 0.03) and LVESV (HR 2.9; 95%-CI: 1.1-7.4; p = 0.03). Diffuse myocardial fibrosis assessed by myocardial native T1 correlates with LV reverse remodeling at six months after valvular surgery. T1 mapping may be a valuable tool to predict LV reverse remodeling in valvular heart disease.
RÉSUMÉ
Portal hypertension is the underlying reason for complications like ascites or gastrointestinal varices in end-stage liver disease. On rare occasions, portal hypertension may be caused by extrahepatic arterioportal shunts. This report illustrates an outstanding case of extrahepatic arterioportal shunting as an uncommon cause of TIPS-refractory portal hypertension. Four-dimensional flow magnetic resonance imaging (4D flow MRI) is a novel non-invasive technique that enables the visualization of complex vascular disorders but has not been put into daily clinical practice in hepatology. In this case, 4D flow MRI enabled the visualization of three abdominal arterioportal shunts as the reason for TIPS-refractory portal hypertension. The quantification of individual shunt flow rates by 4D flow MRI guided our treatment strategy consisting of embolization during interventional angiography and surgical resection of all three arterioportal shunts. In conclusion, this case highlights the usefulness of 4D flow MRI for evaluating shunt flow in cases of complex vascular disorders and portal-hypertensive complications, thus helping to guide therapeutic decisions and monitoring the therapeutic success.
Sujet(s)
Embolisation thérapeutique , Hypertension portale , Humains , Hypertension portale/étiologie , Hypertension portale/chirurgie , Imagerie par résonance magnétique/effets indésirables , Embolisation thérapeutique/effets indésirablesRÉSUMÉ
BACKGROUND: Patients with sickle cell disease (SCD) have a unique form of cardiomyopathy. However, left ventricular ejection fraction (LVEF) is often preserved. Monoplanar long-axis strain (LAS) can be assessed from MRI four-chamber views and may be better at detecting mild systolic dysfunction in these patients. PURPOSE: To compare LAS (monoplanar and biplanar) with LVEF as a marker of systolic dysfunction in SCD patients. STUDY TYPE: Retrospective. SUBJECTS: A total of 20 patients with genetically proven SCD (35 MRI examinations), 39 healthy controls, and 124 patients with systemic iron overload (for validation purposes). FIELD STRENGTH/SEQUENCE: 1.5 T/3 T. Cine balanced steady-state free-precession. ASSESSMENT: Rapidly assessed biplanar LAS from four- and two-chamber views was correlated with age and compared to LVEF by two operators. For validation, biplanar LAS was compared to global longitudinal strain (GLS) using MRI feature-tracking in 124 patients with systemic iron overload. STATISTICAL TESTS: Bland-Altman analysis. Wilcoxon-Mann-Whitney test and Spearman-rank correlation (correlation coefficient, rS ). Receiver-operating-characteristic (ROC) curve analysis (area under the curve, AUC). Bivariate discriminant analysis. Significance level: P < 0.01. RESULTS: There was strong correlation between biplanar LAS and GLS using feature tracking (rS = 0.73). Interoperator agreement showed nonsignificant bias for biplanar LAS (-0.02%; ±95%-agreement interval -2.2%/2.2%, P = 0.9). Biplanar LAS increased significantly with age in controls (rS = 0.70). In SCD patients, biplanar LAS was better correlated with age than monoplanar LAS (r2 = 0.53, standard error of estimate, SEE = 1.4% vs. r2 = 0.37;SEE = 2.0%). ROC analysis of LVEF, biplanar LAS, and age-adjusted Z-scores Z (LAS(age)) showed AUCs of 0.69, 0.75, and 0.86 for differentiation between SCD patients and controls. Bivariate discriminant analysis of biplanar Z (LAS(age)) and LVEF revealed a sensitivity of 63% and a specificity of 95%. DATA CONCLUSION: Rapidly assessed biplanar LAS demonstrated high diagnostic accuracy and was an indicator of mild systolic dysfunction in patients with SCD. Biplanar LAS provided more precise measurements than monoplanar, and normalization to age increased diagnostic accuracy. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.
Sujet(s)
Cardiomyopathies , Surcharge en fer , Dysfonction ventriculaire gauche , Humains , Débit systolique , Fonction ventriculaire gauche , Études rétrospectives , Imagerie par résonance magnétique , Surcharge en fer/imagerie diagnostique , Dysfonction ventriculaire gauche/imagerie diagnostique , Dysfonction ventriculaire gauche/étiologieRÉSUMÉ
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.