Purpose
Patients with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. The mechanisms and disease development are unclear and early secondary liver cancer is a concern. This ...study will describe hepatic imaging findings in a national cohort of adolescents with Fontan circulation.
Methods
The patients prospectively underwent abdominal contrast enhanced magnetic resonance imaging (MRI) including diffusion-weighted imaging. Images were assessed for criteria of fibrosis
/
cirrhosis including characterization of hepatic nodules. These nodules were in addition, assessed by ultrasonography (US). Nodules ≥ 1 cm were investigated and monitored to evaluate malignant transformation. Clinical and hepatic serological data were recorded.
Results
Forty-six patients, median age of 16.5 years (15.4–17.9 years) were enrolled. All patients underwent US examination and MRI was performed in 35/46 patients. On MRI, 60% had hepatomegaly and 37% had signs of fibrosis/cirrhosis. Seven patients had together 13 nodules ≥ 1 cm in diameter. Only 4/13 (17%) where seen on US. Nodules had variable MRI signal characteristics including hepatobiliary contrast enhancement and two nodules revealed portal venous phase ‘wash-out’ on the first examination. No further imaging signs of malignancy were revealed during the follow-up period of median 24.4 (7–42) months.
Conclusion
The majority of adolescents with Fontan circulation had imaging findings of fibrosis/cirrhosis of varying severity. US had low detection rate of hepatic nodules compared to MRI. The imaging work-up before transition to adult cardiology care did not reveal findings suggestive of malignancy. However, the high prevalence of Fontan-associated liver disease calls for surveillance strategies even in childhood.
Background
Children with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. Reliable noninvasive monitoring techniques are lacking or under development.
Objective
To investigate ...surrogate indicators of hepatic fibrosis in adolescents with Fontan circulation by evaluating hepatic magnetic resonance (MR) T1 mapping and extracellular volume fraction measurements compared to US shear-wave elastography.
Materials and methods
We analyzed hepatic native T1 times and extracellular volume fractions with modified Look-Locker inversion recovery. Liver stiffness was analyzed with shear-wave elastography. We compared results between 45 pediatric patients ages 16.7±0.6 years with Fontan circulation and 15 healthy controls ages 19.2±1.2 years. Measurements were correlated to clinical and hemodynamic data from cardiac catheterization.
Results
MR mapping was successful in 35/45 patients, revealing higher hepatic T1 times (774±44 ms) than in controls (632±52 ms;
P
<0.001) and higher extracellular volume fractions (47.4±5.0%) than in controls (34.6±3.8%;
P
<0.001). Liver stiffness was 1.91±0.13 m/s in patients vs. 1.20±0.10 m/s in controls (
P
<0.001). Native T1 times correlated with central venous pressures (r=0.5,
P
=0.007). Native T1 was not correlated with elastography in patients (r=0.2,
P
=0.1) or controls (r = −0.3,
P
=0.3). Extracellular volume fraction was correlated with elastography in patients (r=0.5,
P
=0.005) but not in controls (r=0.2,
P
=0.6).
Conclusion
Increased hepatic MR relaxometry and shear-wave elastography values in adolescents with Fontan circulation suggested the presence of hepatic fibrosis or congestion. Central venous pressure was related to T1 times. Changes were detected differently with MR relaxometry and elastography; thus, these techniques should not be used interchangeably in monitoring hepatic fibrosis.
Background
Assessment of qualitative or subjective image quality in radiology is traditionally performed using a fixed-point scale even though reproducibility has proved challenging.
Objective
Image ...quality of 3-T coronary magnetic resonance (MR) angiography was evaluated using three scoring methods, hypothesizing that a continuous scoring scale like visual analogue scale would improve the assessment.
Materials and methods
Adolescents corrected for transposition of the great arteries with arterial switch operation, ages 9–15 years
(n
=12), and healthy, age-matched controls (
n
=12), were examined with 3-D steady-state free precession magnetic resonance imaging. Image quality of the coronary artery origin was evaluated by using a fixed-point scale (1–4), visual analogue scale of 10 cm and a visual analogue scale with reference points (figurative visual analogue scale). Satisfactory image quality was set to a fixed-point scale 3=visual analogue scale/figurative visual analogue scale 6.6 cm. Statistical analysis was performed using Cohen kappa coefficient and agreement index.
Results
The mean interobserver scores for the fixed-point scale, visual analogue scale and figurative visual analogue scale were, respectively, in the left main stem 2.8, 5.7, 7.0; left anterior descending artery 2.8, 4.7, 6.6; circumflex artery 2.5, 4.5, 6.2, and right coronary artery 3.2, 6.3, 7.7. Scoring with a fixed-point scale gave an intraobserver κ of 0.52–0.77 while interobserver κ was lacking. For visual analogue scale and figurative visual analogue scale, intraobserver agreement indices were, respectively, 0.08–0.58 and 0.43–0.71 and interobserver agreement indices were up to 0.5 and 0.65, respectively.
Conclusion
Qualitative image quality evaluation with coronary 3-D steady-state free precession MR angiography, using a visual analogue scale with reference points, had better reproducibility compared to a fixed-point scale and visual analogue scale. Image quality, being a continuum, may be better determined by this method.
Background: Patency of the coronary arteries is an issue after reports of sudden cardiac death in patients with transposition of the great arteries (TGA) operated with arterial switch (ASO). Recent ...studies give rise to concern regarding the use of ionising radiation in congenital heart disease, and assessment of the coronary arteries with coronary MR angiography (CMRA) might be an attractive non-invasive, non-ionising imaging alternative in these patients. Theoretically, the use of 3.0T CMRA should improve the visualisation of the coronary arteries. The objective of this study was to assess feasibility of 3.0T CMRA at the coronary artery origins by comparing image quality with non-contrast CMRA in ASO TGA patients to healthy age-matched controls, and by comparing image quality with non-contrast CMRA to contrast enhanced CMRA in the patient group. Material and methods: Twelve patients, 9-15 years (mean 11.9 years, standard deviation 1.5 years), and 12 age-matched controls (mean 12.7 years, standard deviation 1.7 years) were examined with 3D balanced steady-state free precession (SSFP). Nine of twelve patients had Gadolinium-enhanced fast low-angle shot (Gd-FLASH) performed after SSFP. Image quality at the coronary artery origins was evaluated subjectively with a 10 cm figurative visual analogue scale (fVAS) and objectively by signal-to-noise and contrast-to-noise ratio (SNR, CNR). Results: All, but one, coronary artery origins were identified. No significant difference in image quality scores was found between patients and controls with SSFP (mean values 6.5 cm—9.1 cm in patients and 7.0 cm—8.0 cm in controls, p-values > 0.1). With SSFP, intra-observer fVAS mean score was 6.7 cm—8.6 cm and with Gd-FLASH 7.7 cm—8.7 cm. CNR was higher with Gd-FLASH (p < 0.03). Intra-observer agreement index (AI) with SSFP was moderate-to-good (0.43–0.71) and with Gd-FLASH good (0.64–0.79) in all origins. Inter-observer AI was good in the left main stem (LMS) with SSFP (0.65). With Gd-FLASH inter-observer AI was good in LMS (0.78) and moderate (0.5) in the left anterior descending artery, but lacking in the other origins though with a good agreement on Bland-Altman plots. Conclusions: Our findings indicate a better, more reproducible image quality with Gd-FLASH than with non-contrast SSFP CMRA on 3.0T for evaluation of the coronary artery origins in ASO TGA children and adolescents.
IntroductionIn classic transposition of the great arteries (TGA), little is known about how the condition impacts ventricular structure, and if/how remodeling occurs as a consequence of the original ...condition and after the arterial switch operation (ASO) in the early neonatal period. We hypothesized that structural differences may be present in ASO TGA patients compared to controls, and sought to quantify these differences to determine if subjects can be defined as healthy or TGA based on ventricular shape information alone.MethodsWe studied population of 12 TGA patients (6 male, age 12±1.5 years) and 12 age-matched controls (4 male, age 13±1.7 years). Ventricular shape was segmented from short-axis CMR images at the end-diastole (ED) phase of the cardiac cycle and ED volume (EDV) was computed from the segmentation. Statistical shape analysis was applied to compute the most common ventricular shape features in the TGA population, after indexing for BSA. Each subject was characterized quantitatively as a combination of these shape features for the control- and TGA-populations. The sum of these values was used as a shape measure. A statistical classification method was applied to this measure to predict the patient group.ResultsSeven shape features captured 95% of the variance of shape in the TGA population and are summarized in the figure (a) with the % of variance of each shape feature given in brackets. The sum of the shape features for both populations is shown in the figure (b), as well as the line that divides the groups (in black). The classification yielded 100% accuracy (i.e. subjects were correctly classified). The resulting receiver operating characteristic curve is shown in the figure (c). There were no EDV differences between groups.ConclusionsWe found significant shape differences between the TGA patients and the healthy controls from the quantified measures of ventricular shape, which was highly accurate in discriminating between the two groups.
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