Search

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The Fontan procedure provides relief from cyanosis in patients with univentricular hearts. A major clinical unmet need is to understand whether the venous flow patterns of the Fontan circulation lead to the development of congestive hepatopathy and other life-threatening complications. Currently, there is no consensus on whether heart beat or respiration is the main driving force of venous return and which one affects the periodic flow changes for the most (i. e., pulsatility). The present study, for the first time, quantified respiratory and cardiac components of the venous flow in the inferior vena cava (IVC) of 14 Fontan patients and 11 normal controls using a novel approach ("physio-matrix"). We found that in contrast to the normal controls, respiration in Fontan patients had a significant effect on venous flow pulsatility, and the ratio of respiration-dependent to the cardiac-dependent pulsatility was positively associated with the retrograde flow. Nevertheless, the main driving force of net IVC flow was the heart beat and not respiration. The separate analysis of the effects of respiration and heart beat provides new insights into the abnormal venous return patterns that may be responsible for adverse effects on liver and bowel of the patients with Fontan circulation.

Transposition of the great arteries (TGA) is caused by discordance between the great arteries and the ventricles. If left untreated, this anomaly has a disastrous perspective. More recent surgical approach for correction includes the Lecompte technique in which the pulmonary bifurcation is transposed anterior to the aorta, which may be less physiologic. Although the early results are excellent, there is potential for future problems involving the great arteries and semilunar valves1. These potential problems necessitate the development of other improved surgical techniques2. Here we report an MRI 4D flow study related to a case of simple TGA whose primary surgical correction - direct spiral arterial switch operation (DSASO) - was performed twenty years ago in an attempt to restore physiologic arrangement among the great arteries and semilunar valves.

To evaluate the ability of non-contrast enhanced magnetic resonance imaging (MRI) techniques to characterize Fontan associated liver disease (FALD) in adolescent and adult Fontan patients. Fontan patients (n = 29) and healthy controls (n = 13) underwent an MRI protocol with T 1 , T 2 and Apparent Diffusion Coefficient (ADC) mapping. Routine FALD screening included abdominal ultrasound and laboratory testing. Median follow-up after Fontan operation was 15.1 (IQR 12.0–16.8) years. Distinct differences in tissue characteristics were visualized. T 1 and T 2 relaxation times were prolonged in Fontan patients, particularly of the right lobe (T 1 : 745 (IQR 715–784) ms vs. 586 (IQR 555–602) ms, p < 0.001; T 2 : 63 (IQR 59–64) ms vs. 58 (IQR 56–60) ms, p = 0.002). Left lobe ADC was lower in Fontan patients (1.10 (IQR 1.06–1.18) x 10−3 mm2/s vs. 1.23 (IQR 1.19–1.29) x 10−3 mm2/s, p < 0.001). T 2 mapping was able to differentiate between controls and Fontan patients with different FALD severity. Right lobe T 2 was higher in patients with moderate or severe in comparison to those with no or mild changes and healthy controls (64 (IQR 61–67) ms vs. 60 (IQR 59–63) ms vs. 58 (IQR 56–60) ms, p = 0.001). Non-contrast enhanced MRI methods are able to visualize regional differences in liver tissue characteristics. T 1 and T 2 relaxation times were prolonged in Fontan patients suggestive of fibrosis or congestive hepatopathy, while reduced ADC might reflect impaired microperfusion. These methods have promising clinical potential for detection of liver abnormalities in Fontan patients. The usefulness of T 2 mapping to grade FALD severity merits further investigation. Non-contrast enhanced liver MRI in Fontan circulation Liver fibrosis is a serious morbidity in patients with Fontan circulation (Fontan associated liver disease, FALD). Fontan patients and healthy controls underwent non-contrast enhanced liver MRI with Diffusion weighted imaging and T1- and T2-mapping. Distinct differences in tissue characteristics were visualized. T1- and T2-relaxation times were prolonged in Fontan patients, particularly of the right lobe. Right lobe T2-relaxation times were higher in Fontan patients with moderate or severe FALD in comparison to healthy controls and those with no or mild FALD. T2-mapping may be a promising non-invasive screening marker to detect and grade FALD. [Display omitted] • Reliable non-invasive methods to monitor Fontan associated liver disease have not been established. • Liver tissue characterization with contrast-free magnetic resonance imaging techniques in Fontan patients and healthy controls • Relaxometry and diffusion weighted imaging maps showed distinct differences between Fontan patients and healthy controls. • Especially T 2 -mapping has promising potential for non-invasive screening of Fontan associated liver disease. [ABSTRACT FROM AUTHOR]

Purpose: The aim of our study was to investigate the technical accuracy of susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM) created to detect intramammary-like calcifications depending on different TEs, volume, and type of calcification samples at 1.5T., Methods: Jello-embedded particles of blackboard chalk and ostrich eggshell ranging in size from 4 to 25 mm 2 were used to simulate intramammary calcifications after testing different base substances and calcifications for their suitability to be used in breast phantoms. Breast phantoms were systematically examined using CT and an optimized 3D multi-echo gradient echo pulse sequence with following parameters: TR/TE, 22/1.88-15.52 ms in 1.24 ms increments; reconstructed voxel, 0.5 × 0.5 × 1.1 mm 3 ; receiver bandwidth, 1120 Hz/Px; flip angle, 15°; integrated parallel imaging technique with a GeneRalized Autocalibrating Partial Parallel Acquisition (GRAPPA) factor of 2/24; and a total acquisition time of 3:00 min. A qualitative evaluation of the dependence of the visualization of calcification samples on volume and TE value was followed by a calculation of the SNR, the contrast-to-noise ratio (CNR) and the creation of SWI and QSM in the sense of a (semi)-quantitative analysis of the images., Results: Jello proved to be a suitable base substance for preparing breast phantoms for SW MRI. Blackboard chalk and ostrich eggshell proved to be suitable for mimicking intramammary-like calcifications. The decrease in the median SNR of the blackboard chalk samples was significantly higher than the corresponding value of the ostrich eggshell samples over the entire TE range (47.5 to 17.0 vs. 16.0 to 6.56, P < 0.0001). The increase in the median CNR of the blackboard chalk samples was significantly higher than the corresponding value of the ostrich eggshell samples over the entire TE range (2.46 to 35.0 vs. 20.2 to 36.8, P = 0.007). With increasing TE value, the signal void volume of the calcification particle increases in the magnitude images as well as in SWI and QSM. Due to the blooming effect, the median gradients of the TE-based changes in signal void volumes were higher in SWI than in magnitude images and in QSM, regardless of the type of calcification particle examined. The maximum magnetic susceptibility of ostrich eggshell samples varied in a TE range of 1.88 to 15.52 ms from -7.2 to -2.51 ppm and that of blackboard chalk from -2.0 to -1.7 ppm. Compared to the manually measured volumes of the calcification particles, both MR-based measurements and CT examinations overestimated the actual sample size. The (non)-significant overestimation in the MRI-data is dependent on the set TE. The CT-based hyperdense volumes were overestimated compared to the corresponding manually measured sample volumes in a range of 109.8%-315.2% for ostrich eggshell samples (P = 0.016) and in a range of 39.9%-156.4% for blackboard chalk samples (P = 0.69)., Conclusion: Our systematic in-vitro investigation of magnitude images, SWI, and QSM revealed that various set TE values, different volumes, and compositions of calcifications have a significant impact on visualizing intramammary(-like) calcifications.

Background: The aim of this work was to create and evaluate a preoperative non-contrast-enhanced (CE) magnetic resonance imaging (MRI)/angiography (MRA) protocol to assess renal function and visualize renal arteries and any abnormalities in potential living kidney donors., Methods: In total, 28 subjects were examined using scintigraphy to determine renal function. In addition, 3D-pseudocontinuous arterial spin labeling (pCASL), a 2D-non-CE electrocardiogram-triggered radial quiescent interval slice-selective (QISS-MRA), and 4D-CE time-resolved angiography with interleaved stochastic trajectories (CE-MRA) were performed to assess renal perfusion, visualize renal arteries and detect any abnormalities. Two glomerular filtration rates [described by Gates (GFR G ) and according to the Chronic Kidney Disease Epidemiology Collaboration formula (GFR CKD-EPI )]. The renal volumes were determined using both MRA techniques., Results: The mean value of regional renal blood flow (rRBF) on the right side was significantly higher than that on the left. The agreements between QISS-MRA and CE-MRA concerning the assessment of absence or presence of an aberrant artery and renal arterial stenosis were perfect. The mean renal volumes measured in the right kidney with QISS-MRA were lower than the corresponding values of CE-MRA. In contrast, the mean renal volumes measured in the left kidney with both MRA techniques were similar. The correlation between the GFR G and rRBF was compared in the same manner as that between GFR CKD-EPI and rRBF., Conclusion: The combination of pCASL and QISS-MRA constitute a reliable preoperative protocol with a total measurement time of <10 min without the potential side effects of gadolinium-based contrast agents or radiation exposure., Competing Interests: R.R.E. and I.K. receive research support from Siemens Healthcare. R.R.E. receives royalties from Siemens Healthcare. The other authors declare that they have no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

Background: Soft-tissue sarcomas (STS) are rare malignancies of the soft tissue., Purpose: To assess whether the magnetic resonance imaging (MRI) configuration of primary STS can predict the configuration of a recurring tumor and whether the MRI configuration of multiple recurrences differs in one and the same patient., Material and Methods: Thirty-nine patients with histologically proven recurrent STS were included in this retrospective study and underwent pre- and post-treatment MRI. Three main configurations of primary and recurrent tumors were identified: polycyclic/multilobulated; ovoid/nodular; and streaky., Results: Sixty recurrent lesions were detected: 34 ovoid/nodular; 15 polycyclic/multilobulated; and 11 streaky. Five recurrences were multifocal and eight were bifocal. Of 39 patients, 28 (71.8%) presented one recurrence within the MRI follow-up period ( P  = 0.006); in 10 patients (25.6%), up to three different configurations of recurring STS were identified in one patient. Recurrences of polycyclic/multilobulated primaries were mostly ovoid/nodular (48%; P  = 0.003) or polycyclic/multilobulated (37%; P  = 0.014), and recurring ovoid/nodular STS significantly most often showed the same configuration as the primary tumor (85%; P  < 0.001). Primary STS with a streaky configuration recurred in all three configurations in roughly equal proportions. Homogeneity/heterogeneity and tumor borders are significantly associated with the configuration of recurrences., Conclusion: Primary STS configuration may help predict recurrent tumor configuration when the primary STS had a polycyclic/multilobulated or ovoid/nodular configuration. However, recurrent STS configuration can also differ from primary STS configuration, especially when the primary STS had a streaky configuration, rendering recurrent STS difficult to predict. Different configurations of recurrent STS in one and the same patient are common.

Background: The aim of the study was to assess whether the configuration of primary soft-tissue sarcoma (STS) on MRI correlates with the grade of malignancy., Patients and Methods: 71 patients with histologically proven STS were included. Primary STS were examined for configuration, borders, and volume on MRI. The tumors were divided into high-grade (G3), intermediate-grade (G2) and low-grade (G1) STS according to the grading system of the French Federation of Cancer Centers Sarcoma Group (FNCLCC)., Results: 30 high-grade, 22 intermediate-grade and 19 low-grade primary STS lesions were identified. High- and intermediate-grade (G3/2) STS significantly most often appeared as polycyclic/multilobulated tumors (p < 0.001 and p = 0.002, respectively). Low-grade (G1) STS mainly showed an ovoid/nodular or streaky configuration (p = 0.008), and well-defined borders. The appearance of high-, intermediate- and low-grade STS with an ovoid/nodular configuration were mainly the same on MRI. All streaky G3/2 sarcoma and 17 of 20 patients with polycyclic/multilobulated G3 sarcoma showed infiltrative borders. High-grade streaky and polycyclic/multilobulated STS are larger in volume, compared to intermediate- and low-grade STS., Conclusions: Configuration of STS on MRI can indicate the grade of malignancy. Higher-grade (G2/3) STS most often show a polycyclic/multilobulated configuration, while low-grade STS are mainly ovoid/nodular or streaky. Infiltrative behavior might suggest higher-grade STS in streaky and polycyclic/multilobulated STS., (© 2021 Sam Sedaghat, Mona Salehi Ravesh, Maya Sedaghat, Marcus Both, Olav Jansen, published by Sciendo.)