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GRANT SUPPORT: This project was funded by the Research Council of Norway. BACKGROUND: Oxygen uptake through the gastrointestinal tract after oral administration of oxygenated water in humans is not well studied and is debated in the literature. Due to the paramagnetic properties of oxygen and deoxyhemoglobin, MRI as a technique might be able to detect changes in relaxometry values caused by increased oxygen levels in the blood. PURPOSE: To assess whether oxygen dissolved in water is absorbed from the gastrointestinal tract and transported into the bloodstream after oral administration. STUDY TYPE: A randomized, double-blinded, placebo-controlled crossover trial. POPULATION/SUBJECTS: Thirty healthy male volunteers age 20-35. FIELD STRENGTH/SEQUENCE: 3T/Modified Look-Locker inversion recovery (MOLLI) T1 -mapping and multi fast field echo (mFFE) T2 *-mapping. ASSESSMENT: Each volunteer was scanned in two separate sessions. T1 and T2 * maps were acquired repeatedly covering the hepatic portal vein (HPV) and vena cava inferior (VCI, control vein) before and after intake of oxygenated or control water. Assessments were done by placing a region of interest in the HPV and VCI. STATISTICAL TEST: A mixed linear model was performed to the compare control vs. oxygen group. RESULTS: Drinking caused a mean 1.6% 95% CI (1.1-2.0% P < 0.001) increase in T1 of HPV blood and water oxygenation attributed another 0.70% 95% confidence interval (CI) (0.07-1.3% P = 0.028) increase. Oxygenation did not change T1 in VCI blood. Mean T2 * increased 9.6% 95% CI (1.7-17.5% P = 0.017) after ingestion of oxygenated water and 1.2% 95% CI (-4.3-6.8% P = 0.661) after ingestion of control water. The corresponding changes in VCI blood were not significant. DATA CONCLUSION: Ingestion of water caused changes in T1 and T2 * of HPV blood compatible with dilution due to water absorption. The effects were enhanced by oxygen. Assessment of oxygen enrichment of HPV blood was not possible due to the dilution effect. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:720-728.
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Pulmón , Imagen por Resonancia Magnética , Adulto , Voluntarios Sanos , Humanos , Modelos Lineales , Masculino , Reproducibilidad de los Resultados , Agua , Adulto JovenRESUMEN
OBJECTIVE: To investigate the sensitivity of modified Look-Locker inversion recovery (MOLLI) to measure changes in dissolved oxygen (DO) concentrations in water samples and to calculate sequence-specific relaxivity (r1m) and limit of detection (LOD). MATERIALS AND METHODS: Ten water samples with a range of DO concentrations were scanned at 3 T using two variations of MOLLI schemes. Using linear regression the r1 of DO was estimated from the measured DO concentrations and T1 relaxation rates (R1). The results were combined with previously reported values on in vivo stability measures of the MOLLI sequences and used to estimate a LOD. RESULTS: DO concentrations ranged from 0.5 to 21.6 mg L-1. A linear correlation between DO and R1 was obtained with both MOLLI sequences, with an average correlation coefficient (R2) 0.9 and an average estimated r1 ([Formula: see text]) of 4.45 × 10-3 s-1 mg-1 L. Estimated LOD was ≈ 10 mg L-1. CONCLUSION: MOLLI T1-mapping sequences may be used for detecting dissolved oxygen in vivo at 3 T with an [Formula: see text] in the range 4.18-4.8 × 10-3 s-1 mg-1 L and a corresponding LOD for dissolved oxygen of approximately 10 mg L-1. MOLLI-based T1 mapping may be a useful non-invasive tool for quantification of in vivo changes of DO concentration during oxygen challenges.
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Interpretación de Imagen Asistida por Computador/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Oxígeno/química , Algoritmos , Medios de Contraste , Límite de Detección , Fantasmas de Imagen , Análisis de RegresiónRESUMEN
OBJECTIVE: To investigate the effects of a range of parameter settings on T1 measurement stability in the portal vein using the T1-mapping sequences Look-Locker (LL) and Modified Look-Locker inversion recovery (MOLLI). MATERIALS AND METHODS: Ten different versions of LL and MOLLI sequences were tested and compared to a reference sequence provided by the MR manufacturer. Ten healthy volunteers were imaged multiple times on two separate scan days at 3T. The mean T1 values and coefficient of variation (CoV) were calculated for each of the ten sequences and compared to the reference sequence. RESULTS: Six of the tested sequences had T1 values close to the reference sequence; among those, three sequences achieved lower CoV than the reference sequence. Lowest CoV was achieved using a non-triggered LL sequence with 5 beat readout and a 45o flip angle (mean T1 1733 ms ± 89 ms, CoV 1.3% ± 0.58%). CONCLUSION: T1-measurements in the hepatic portal vein can be performed with high precision using either MOLLI or LL sequences provided that LL sampling duration is sufficiently long and flip angle sufficiently high. The advantage of constant timing outweighed the advantage of ECG-triggering.
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Hígado/irrigación sanguínea , Imagen por Resonancia Magnética , Vena Porta/diagnóstico por imagen , Adulto , Artefactos , Medios de Contraste , Electrocardiografía , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Procesamiento de Imagen Asistido por Computador , Masculino , Miocardio/patología , Fantasmas de Imagen , Flujo Sanguíneo Regional , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
Aims: Anthracycline treatment may cause myocyte loss and expansion of the myocardial extracellular volume (ECV) fraction by oedema and fibrosis. We tested the hypotheses that adjuvant treatment for early breast cancer with the anthracycline epirubicin is dose dependently associated with increased ECV fraction and total ECV, as well as reduced total myocardial cellular volume, and that these changes could be prevented by concomitant angiotensin or beta-adrenergic blockade. Methods and results: PRevention of cArdiac Dysfunction during Adjuvant breast cancer therapy (PRADA) was a 2 × 2 factorial, placebo-controlled, double-blinded trial of candesartan and metoprolol. Sixty-nine women had valid ECV measurements. ECV fraction, total ECV, and total cellular volume were measured by cardiovascular magnetic resonance before and at the completion of anthracycline therapy. ECV fraction increased from 27.5 ± 2.7% to 28.6 ± 2.9% (P = 0.002). A cumulative doxorubicin equivalent dose of 268 mg/m2 was associated with greater increase in ECV fraction than doses <268 mg/m2 (mean change 3.4% [95% confidence interval (CI) 1.2, 5.5] vs. 0.7% [95% CI 0.0, 1.5], P = 0.006), as well as greater increase in total ECV (1.9 mL [95% CI 0.4, 3.5] vs. 0.1 mL [95% CI -0.6, 0.8], P = 0.04). In patients receiving candesartan, total cellular volume decreased (-3.5 mL [95% CI - 4.7, -2.2], P < 0.001) while in patients not receiving candesartan, it remained unchanged (P = 0.45; between group difference P = 0.003). Conclusions: Anthracycline therapy is associated with dose-dependent increase in ECV fraction and total ECV. Concomitant treatment with candesartan reduces left ventricular total cellular volume.
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Antraciclinas/efectos adversos , Bencimidazoles/efectos adversos , Neoplasias de la Mama/tratamiento farmacológico , Cardiotoxicidad/diagnóstico por imagen , Imagen por Resonancia Cinemagnética/métodos , Tetrazoles/efectos adversos , Adulto , Anciano , Antraciclinas/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Bencimidazoles/uso terapéutico , Compuestos de Bifenilo , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Cardiotoxicidad/mortalidad , Cardiotoxicidad/fisiopatología , Quimioterapia Adyuvante , Ciclofosfamida/efectos adversos , Ciclofosfamida/uso terapéutico , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Epirrubicina/efectos adversos , Epirrubicina/uso terapéutico , Femenino , Fluorouracilo/efectos adversos , Fluorouracilo/uso terapéutico , Hospitales Universitarios , Humanos , Estimación de Kaplan-Meier , Mastectomía/métodos , Persona de Mediana Edad , Noruega , Pronóstico , Estudios Prospectivos , Medición de Riesgo , Estadísticas no Paramétricas , Volumen Sistólico/efectos de los fármacos , Análisis de Supervivencia , Tetrazoles/uso terapéuticoRESUMEN
PURPOSE: To implement a dynamic contrast-based multi-echo MRI sequence in assessment of rectal cancer and evaluate associations between histopathologic data and the acquired dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) -MRI parameters. MATERIALS AND METHODS: This pilot study reports results from 17 patients with resectable rectal cancer. Dynamic contrast-based multi-echo MRI (1.5T) was acquired using a three-dimensional multi-shot EPI sequence, yielding both DCE- and DSC-data following a single injection of contrast agent. The Institutional Review Board approved the study and all patients provided written informed consent. Quantitative analysis was performed by pharmacokinetic modeling on DCE data and tracer kinetic modeling on DSC data. Mann-Whitney U-test and receiver operating characteristics curve statistics was used to evaluate associations between histopathologic data and the acquired DCE- and DSC-MRI parameters. RESULTS: For patients with histologically confirmed nodal metastasis, the primary tumor demonstrated a significantly lower Ktrans and peak change in R2*, R2*-peakenh , than patients without nodal metastasis, showing a P-value of 0.010 and 0.005 for reader 1, and 0.043 and 0.019 for reader 2, respectively. CONCLUSION: This study shows the feasibility of acquiring DCE- and DSC-MRI in rectal cancer by dynamic multi-echo MRI. A significant association was found between both Ktrans and R2*-peakenh in the primary tumor and histological nodal status of the surgical specimen, which may improve stratification of patients to intensified multimodal treatment. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:194-206.