Fast and optimized T<sub>1</sub> mapping technique for the noninvasive quantification of gastric secretion

Treier, Reto; Steingoetter, Andreas; Goetze, Oliver; Fox, Mark; Fried, Michael; Schwizer, Werner; Boesiger, Peter

doi:10.1002/jmri.21400

Cited by 24 publications

(45 citation statements)

References 24 publications

(34 reference statements)

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“…metal supplements that could function as a MRI contrast marker. The test meal was labelled with 167.5 M of MRI contrast agent (CA, DOTAREM  , Guerbet, Villepinte, France) and 100mg 13 C-Acetate. In-vitro experiments confirmed acid stability of the test meal.…”

Section: Secretion Stimulating Test Mealmentioning

confidence: 99%

“…MRI has recently been proposed for the noninvasive assessment of gastric secretion using a fast T1 mapping sequence (12). By measuring the changes in T1 relaxation times of a MRI contrast agent (DOTAREM  , Guerbet, Villepinte, France) labeled liquid test meal, this imaging method allowed the separation of drug induced secretion from the test meal (13)(14). To date meal induced gastric secretion and its interaction with meal emptying has not yet been analyzed by noninvasive methods.…”

Section: Introductionmentioning

confidence: 99%

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Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Sauter

Curcic

Menne³

et al. 2012

Neurogastroenterology Motil

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BACKGROUND: The stimulation and intragastric accumulation of gastric secretion has been recognized as an important factor in gastroesophageal reflux disease. However, the interaction of gastric secretion and meal emptying has not been fully understood. Current methods to assess gastric secretion are either invasive or unable to provide information on its volume, distribution and dynamics. The aim of this study was to quantify the interaction between meal emptying and meal induced gastric secretion by using quantitative magnetic resonance imaging (MRI) and pharmacokinetic analysis. METHODS: A chocolate test meal was developed which is secretion stimulating and MRI compatible. Meal emptying and gastric secretion were assessed in fourteen healthy volunteers using a validated quantitative MRI technique. A population based pharmacokinetic model was developed and applied to the extracted volume data, assessing the meal emptying rate, rate of secretion and their interaction. KEY RESULTS: The test meal continuously induced gastric secretion in all subjects, which partly accumulated at the meal-air interface, forming a 'secretion layer' in the proximal stomach. Traditional fitting detected a significant correlation between meal emptying rate and rate of secretion. The pharmacokinetic model quantified this interaction and estimated a 2.3 ± 1 fold higher effect of meal on secretion than vice versa. The efficacy of the emptied meal to produce gastric secretion was 61%. CONCLUSIONS 38; INFERENCES: The combined quantitative MRI and pharmacokinetic model approach allows for the quantification of gastric secretion volume and its interaction on meal emptying. The observed secretion layer might explain previous findings postulating the presence of an intragastric 'acid pocket'.

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Section: Secretion Stimulating Test Mealmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Sauter

Curcic

Menne³

et al. 2012

Neurogastroenterology Motil

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“…Due to its time efficiency, AFI is useful for correction of errors caused by B 1 nonuniformities in quantitative in vivo imaging applications, and particularly, in VFA T 1 mapping (4,(13)(14)(15). Incomplete spoiling in AFI also was identified as a cause of B 1 measurement errors, and the use of diffusion-based gradient spoiling was shown to improve accuracy of this method (16,17).…”

mentioning

confidence: 99%

Optimal radiofrequency and gradient spoiling for improved accuracy of T₁ and B₁ measurements using fast steady‐state techniques

Yarnykh¹

2010

Magnetic Resonance in Med

144

227

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Variable flip angle T 1 mapping and actual flip-angle imaging B 1 mapping are widely used quantitative MRI methods employing radiofrequency spoiled gradient-echo pulse sequences. Incomplete elimination of the transverse magnetization in these sequences has been found to be a critical source of T 1 and B 1 measurement errors. In this study, comprehensive theoretical analysis of spoiling-related errors in variable flip angle and actual flip-angle imaging methods was performed using the combined isochromat summation and diffusion propagator model and validated by phantom experiments. The key theoretical conclusion is that correct interpretation of spoiling phenomena in fast gradient-echo sequences requires accurate consideration of the diffusion effect. A general strategy for improvement of T 1 and B 1 measurement accuracy was proposed based on the strong spoiling regimen, where diffusion-modulated spatial averaging of isochromats becomes a dominant factor determining magnetization evolution. Practical implementation of strongly spoiled variable flip angle and actual flip-angle imaging techniques requires sufficiently large spoiling gradient areas (A G ) in combination with optimal radiofrequency phase increments (f 0 ). Optimal regimens providing <2% relative T 1 and B 1 measurement errors in a variety of tissues were theoretically derived for prospective in vivo variable flip angle (pulse repetition time 5 (1) is a widely used method allowing generation of T 1 -weighted contrast in gradient echo (GRE) sequences with short pulse repetition time (TR). Technically, RF spoiling is achieved by linearly incrementing the phase of an RF pulse between successive TR with a specific value of the phase increment. After the initial publication (1) suggested optimal phase increments of 117 or 123 , several other values were proposed (2-4). Default settings of the RF phase increment also vary between MRI equipment manufacturers (5). While all these approaches generally allow acquisition of heavily T 1 -weighted GRE images in the steady state, special attention should be given to the role of RF spoiling in quantitative imaging methods.One of most widely used quantitative applications of the RF spoiled GRE sequence is the variable flip angle (VFA) method for T 1 mapping (6,7). In modern implementations, the VFA method takes advantage of a very short TR achievable due to RF spoiling, which allows time-efficient three-dimensional implementation with large anatomic coverage (8-10). Accuracy of VFA T 1 measurements was extensively studied in aspects of optimal flip-angle sampling (7-10) and correction of amplitude of RF field (B 1 ) nonuniformities (4,9,10). Recently, incomplete spoiling was identified as a critical source of errors in the VFA method (4,5,11). While data processing in this method relies on the ideally spoiled signal equation (12), the use of fast RF spoiled sequences may result in partial preservation of transverse coherences and, therefore, deviation of the signal behavior from the idealized theoretical model. Techn...

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“…Gastric content volume data, as presented in Kuyumcu et al ., was used to extract meal volume (MV) by subtracting secretion volume using the combination of the standard gradient echo sequence and T1 mapping MRI data according to previously reported procedures . The resulting MV curves (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Magnetic resonance imaging (MRI) has recently been validated for the assessment of gastric motor function . Magnetic resonance imaging allows to visualize the volume and distribution of the ingested meal and of gastric secretion.…”

Section: Introductionmentioning

confidence: 99%

On the validity of the ¹³C‐acetate breath test for comparing gastric emptying of different liquid test meals: a validation study using magnetic resonance imaging

Bluemel

Menne²,

Fried

et al. 2015

Neurogastroenterology Motil

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Background 13C‐acetate breath testing (BT) is applied to assess and compare gastric emptying of liquid meals. Gastric half‐emptying times (t50) from BT show offsets compared to t50 values from γ‐scintigraphy and ultrasonography. Linear transformations have been proposed to correct these offsets. This investigation critically validates the BT for the assessment of liquid gastric emptying by using simultaneously recorded meal and total gastric content volume emptying data from magnetic resonance imaging (MRI). Methods Data were collected during a recently published double‐blind, randomized, cross‐over MRI gastric emptying study of three 13C‐labeled enteral formulas differing in protein sources (PMID: 24699556). Breath testing‐derived t50 was computed with the analysis methods commonly applied in gastric emptying research, i.e., the exponential‐beta function and the Wagner–Nelson (WN) method, respectively. Key Results Breath testing t50 values from exponential‐beta function and WN method showed a positive and negative offset to MRI data, respectively. Linear regression detected low concordance between MRI and both BT methods revealing meal specific and emptying rate‐dependent offsets. The WN method showed worse agreement and correlation with MRI emptying data. Breath testing rather reflected meal volume than total gastric content volume emptying. Conclusions & Inferences This validation study indicates that the 13C‐acetate breath test may not be applied to compare gastric emptying of arbitrary liquid meals without prior validation by imaging methods. t50 values from BT are biased by (i) the properties of the meal and (ii) the selected method used for 13CO2 exhalation analysis. No linear transformation common for all meals was applicable to correct the offsets between BT and MRI.

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Fast and optimized T₁ mapping technique for the noninvasive quantification of gastric secretion

Cited by 24 publications

References 24 publications

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Optimal radiofrequency and gradient spoiling for improved accuracy of T₁ and B₁ measurements using fast steady‐state techniques

On the validity of the ¹³C‐acetate breath test for comparing gastric emptying of different liquid test meals: a validation study using magnetic resonance imaging

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Fast and optimized T1 mapping technique for the noninvasive quantification of gastric secretion

Cited by 24 publications

References 24 publications

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

Optimal radiofrequency and gradient spoiling for improved accuracy of T1 and B1 measurements using fast steady‐state techniques

On the validity of the 13C‐acetate breath test for comparing gastric emptying of different liquid test meals: a validation study using magnetic resonance imaging

Contact Info

Product

Resources

About

Fast and optimized T₁ mapping technique for the noninvasive quantification of gastric secretion

Optimal radiofrequency and gradient spoiling for improved accuracy of T₁ and B₁ measurements using fast steady‐state techniques

On the validity of the ¹³C‐acetate breath test for comparing gastric emptying of different liquid test meals: a validation study using magnetic resonance imaging