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- Liefke, Jonas, et al.
(författare)
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Fetal growth restriction followed by very preterm birth is associated with smaller kidneys but preserved kidney function in adolescence
- 2023
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Ingår i: Pediatric Nephrology. - : Springer Science and Business Media LLC. - 1432-198X .- 0931-041X. ; 38:6, s. 1855-1866
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Tidskriftsartikel (refereegranskat)abstract
- Background: Preterm birth and fetal growth restriction (FGR) are associated with structural and functional kidney changes, increasing long-term risk for chronic kidney disease and hypertension. However, recent studies in preterm children are conflicting, indicating structural changes but normal kidney function. This study therefore assessed kidney structure and function in a cohort of adolescents born very preterm with and without verified FGR.Methods: Adolescents born very preterm with FGR and two groups with appropriate birthweight (AGA) were included; one matched for gestational week at birth and one born at term. Cortical and medullary kidney volumes and T1 and T2* mapping values were assessed by magnetic resonance imaging. Biochemical markers of kidney function and renin-angiotensin-aldosterone system (RAAS) activation were analyzed.Results: Sixty-four adolescents were included (13-16 years; 48% girls). Very preterm birth with FGR showed smaller total (66 vs. 75 ml/m2; p = 0.01) and medullary volume (19 vs. 24 ml/m2; p < 0.0001) compared to term AGA. Corticomedullary volume ratio decreased from preterm FGR (2.4) to preterm AGA (2.2) to term AGA (1.9; p = 0.004). There were no differences in T1 or T2* values (all p ≥ 0.34) or in biochemical markers (all p ≥ 0.12) between groups.Conclusions: FGR with abnormal fetal blood flow followed by very preterm birth is associated with smaller total kidney and medullary kidney volumes, but not with markers of kidney dysfunction or RAAS activation in adolescence. Decreased total kidney and medullary volumes may still precede a long-term decrease in kidney function, and potentially be used as a prognostic marker. A higher resolution version of the Graphical abstract is available as Supplementary information.
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- Bidhult, Sebastian, et al.
(författare)
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Independent validation of metric optimized gating for fetal cardiovascular phase-contrast flow imaging
- 2019
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 1522-2594 .- 0740-3194. ; 81:1, s. 495-503
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To validate metric optimized gating phase-contrast MR (MOG PC-MR) flow measurements for a range of fetal flow velocities in phantom experiments. 2) To investigate intra- and interobserver variability for fetal flow measurements at an imaging center other than the original site.METHODS: MOG PC-MR was compared to timer/beaker measurements in a pulsatile flow phantom using a heart rate (∼145 bpm), nozzle diameter (∼6 mm), and flow range (∼130-700 mL/min) similar to fetal imaging. Fifteen healthy fetuses were included for intra- and interobserver variability in the fetal descending aorta and umbilical vein.RESULTS: Phantom MOG PC-MR flow bias and variability was 2% ± 23%. Accuracy of MOG PC-MR was degraded for flow profiles with low velocity-to-noise ratio. Intra- and interobserver coefficients of variation were 6% and 19%, respectively, for fetal descending aorta; and 10% and 17%, respectively, for the umbilical vein.CONCLUSION: Phantom validation showed good agreement between MOG and conventionally gated PC-MR, except for cases with low velocity-to-noise ratio, which resulted in MOG misgating and underestimated peak velocities and warranted optimization of sequence parameters to individual fetal vessels. Inter- and intraobserver variability for fetal MOG PC-MR imaging were comparable to previously reported values.
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- Cain, Peter A, et al.
(författare)
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Age and gender specific normal values of left ventricular mass, volume and function for gradient echo magnetic resonance imaging: a cross sectional study.
- 2009
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Ingår i: BMC medical imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about age-specific normal values for left ventricular mass (LVM), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) by cardiac magnetic resonance imaging (CMR) is of importance to differentiate between health and disease and to assess the severity of disease. The aims of the study were to determine age and gender specific normal reference values and to explore the normal physiological variation of these parameters from adolescence to late adulthood, in a cross sectional study.
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- Hedström, Erik, et al.
(författare)
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Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging
- 2006
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 24:1, s. 77-83
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate whether an extracellular gadolinium-(Gd)-based contrast agent (CA) enters nonperfused myocardium during acute coronary occlusion, and whether nonperfused myocardium presents as hyperintense in delayed contrast-enhanced (DE) MR images in the absence of CA in that region. MATERIALS AND METHODS: The left anterior descending coronary artery (LAD) was occluded for 200 minutes in six pigs. The longitudinal relaxation rate (R(1)) in blood, perfused myocardium, and nonperfused myocardium was repeatedly measured using a Look-Locker sequence before and during the first hour after administration of Gd-DTPA-BMA. RESULTS: While blood and perfused myocardium showed a major increase in R(1) after CA administration, nonperfused myocardium did not. R(1) in nonperfused myocardium was significantly lower than in blood and perfused myocardium during the first hour after CA administration. When the signal from perfused myocardium was nulled, demarcation of the hyperintense nonperfused myocardium was achieved in all of the study animals. CONCLUSION: Gd-DTPA-BMA does not enter ischemic myocardium within one hour after administration during acute coronary occlusion. The ischemic region with complete absence of CA still appears bright when the signal from perfused myocardium is nulled using inversion-recovery DE-MRI. This finding is important for understanding the basic pathophysiology of inversion-recovery viability imaging, as well as for imaging of acute coronary syndromes.
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| 6. |
- Axelsson, Jimmy, et al.
(författare)
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Ejection fraction in left bundle branch block is disproportionately reduced in relation to amount of myocardial scar
- 2018
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 0022-0736 .- 1532-8430. ; 51:6, s. 1071-1076
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The relationship between left ventricular (LV) ejection fraction (EF) and LV myocardial scar can identify potentially reversible causes of LV dysfunction. Left bundle branch block (LBBB) alters the electrical and mechanical activation of the LV. We hypothesized that the relationship between LVEF and scar extent is different in LBBB compared to controls. Methods: We compared the relationship between LVEF and scar burden between patients with LBBB and scar (n = 83), and patients with chronic ischemic heart disease and scar but no electrocardiographic conduction abnormality (controls, n = 90), who had undergone cardiovascular magnetic resonance (CMR) imaging at one of three centers. LVEF (%) was measured in CMR cine images. Scar burden was quantified by CMR late gadolinium enhancement (LGE) and expressed as % of LV mass (%LVM). Maximum possible LVEF (LVEFmax) was defined as the function describing the hypotenuse in the LVEF versus myocardial scar extent scatter plot. Dysfunction index was defined as LVEFmax derived from the control cohort minus the measured LVEF. Results: Compared to controls with scar, LBBB with scar had a lower LVEF (median [interquartile range] 27 [19–38] vs 36 [25–50] %, p < 0.001), smaller scar (4 [1–9] vs 11 [6–20] %LVM, p < 0.001), and greater dysfunction index (39 [30–52] vs 21 [12–35] % points, p < 0.001). Conclusions: Among LBBB patients referred for CMR, LVEF is disproportionately reduced in relation to the amount of scar. Dyssynchrony in LBBB may thus impair compensation for loss of contractile myocardium.
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| 8. |
- Lundin, Magnus, et al.
(författare)
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Left ventricular global wall thickness is easily calculated, detects and characterizes hypertrophy, and has prognostic utility
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Cardiovascular magnetic resonance (CMR) can be used to measure left ventricular end-diastolic volume (LVEDV) and left ventricular mass (LVM). However, there is currently no good way to measure the normality of LVM in relation to a given LVEDV. We hypothesized that a simple measure of left ventricular global wall thickness (GWT) would be accurate, beneficial for detecting and characterizing hypertrophy, and have prognostic significance.METHODS: Subjects underwent CMR at 1.5T, including healthy volunteers (n=99) and patients assessed for heart disease (n=2828).RESULTS: GWT calculated from LVEDV and LVM had excellent agreement with measured mean end-diastolic wall thickness of the entire left ventricle (bias 0.01±0.23mm). GWT was most predictive of death or hospitalization for heart failure in patients with normal findings by CMR (n=326, log-rank 26.8, p<0.001, median [interquartile range] follow-up 5.8 [5.0–6.7] years). GWT indexed to body surface area (GWTi) was most predictive of outcomes in patients with normal LVEDV index (n=1352, log-rank 36.4, p<0.001, follow-up 5.5 [4.1–6.5] years). Patients with concentric remodeling had worse prognosis than the normal patients (p=0.02), and the patients with hypertrophy had worse prognosis than both normal patients (p<0.001) and patients with concentric remodeling (p=0.045), see Figure 1. Of patients with suspected heart disease but normal CMR findings regarding left ventricular volumes, function, mass, and scar, 22% were found to have increased mean GWTi corresponding to concentric remodeling, see Figure 2.CONCLUSIONS: Left ventricular GWT is an intuitive measure that can be easily calculated from mass and volume with high accuracy, and has prognostic utility in patients with normal CMR findings. Also, GWTi classifies hypertrophy as concentric or eccentric, and detects concentric remodeling in a substantial portion of patients with otherwise normal findings.
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| 10. |
- Seemann, Felicia, et al.
(författare)
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Noninvasive Quantification of Pressure-Volume Loops From Brachial Pressure and Cardiovascular Magnetic Resonance
- 2019
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Ingår i: Circulation. Cardiovascular imaging. - 1942-0080. ; 12:1, s. 008493-008493
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pressure-volume (PV) loops provide a wealth of information on cardiac function but are not readily available in clinical routine or in clinical trials. This study aimed to develop and validate a noninvasive method to compute individualized left ventricular PV loops. METHODS: The proposed method is based on time-varying elastance, with experimentally optimized model parameters from a training set (n=5 pigs), yielding individualized PV loops. Model inputs are left ventricular volume curves from cardiovascular magnetic resonance imaging and brachial pressure. The method was experimentally validated in a separate set (n=9 pig experiments) using invasive pressure measurements and cardiovascular magnetic resonance images and subsequently applied to human healthy controls (n=13) and patients with heart failure (n=28). RESULTS: There was a moderate-to-excellent agreement between in vivo-measured and model-calculated stroke work (intraclass correlation coefficient, 0.93; bias, -0.02±0.03 J), mechanical potential energy (intraclass correlation coefficient, 0.57; bias, -0.04±0.03 J), and ventricular efficiency (intraclass correlation coefficient, 0.84; bias, 3.5±2.1%). The model yielded lower ventricular efficiency ( P<0.0001) and contractility ( P<0.0001) in patients with heart failure compared with controls, as well as a higher potential energy ( P<0.0001) and energy per ejected volume ( P<0.0001). Furthermore, the model produced realistic values of stroke work and physiologically representative PV loops. CONCLUSIONS: We have developed the first experimentally validated, noninvasive method to compute left ventricular PV loops and associated quantitative measures. The proposed method shows significant agreement with in vivo-derived measurements and could support clinical decision-making and provide surrogate end points in clinical heart failure trials.
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