VIBE mit paralleler Akquisitionstechnik - eine neue Möglichkeit der dynamischen kontrastverstärkten MRT der Leber

Dobritz, Martin; Radkow, Tanja; Nittka, Mathias; Bautz, W; Fellner, F. A.

doi:10.1055/s-2002-32223

Cited by 23 publications

(1 citation statement)

References 4 publications

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“…A patient underwent DCE-MRI with paramagnetic contrast agent Gd-DTPA imaged with a Siemens Sonata scanner using the "Vibe FS tra BH post iPat" protocol [4], a T1 weighted imaging sequence. The quantity of contrast media, intravenously automatically injected in the arm, was around 20-25 ml, during 5-30s.…”

Section: Acquisition and Roi Selectionmentioning

confidence: 99%

Automatic liver tumor diagnosis with Dynamic-Contrast Enhanced MRI

Caldeira

Silva

Sanches

2008

2008 15th IEEE International Conference on Image Processing

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Dynamic-Contrast Enhanced MRI is currently used as a complementary diagnosis tool to assess the malignancy of the liver tumor, called hepatoma or adult primary liver cancer. This paper proposes a set of features and computation methods to extract them in order to design a classifier for automatic diagnosis of the hepatoma.A dynamic discrete linear pharmacokinetic model is used to estimate the perfusion curves from the noisy observations, based on the multi-compartment paradigm. The arterial response to the contrast agent bolus injection, called arterial input function, is also estimated since no arteries are available in the neighborhood of the tumor.The compensation of involuntary movements of the patient, such as the respiratory activity, during the acquisition process is performed using a Mutual Information based registration algorithm with non-rigid transformations. The tumor is isolated in a small region of interest in order to speed up the analysis and the tumor itself is segmented using an active contour algorithm.The classification of the tumor can be based on the mean and variance values of the Maximum, WashIn and WashOut rates of the perfusion curves inside the tumor as it is shown that these rates are adequate discriminative features to automatically classify the tumors with respect to its malignancy.Tests using real data are used to illustrate the ability of using these features to classify the tumor with respect to its malignancy.

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Section: Acquisition and Roi Selectionmentioning

confidence: 99%

Automatic liver tumor diagnosis with Dynamic-Contrast Enhanced MRI

Caldeira

Silva

Sanches

2008

2008 15th IEEE International Conference on Image Processing

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Accelerated dynamic MR imaging with a parallel imaging technique for hypervascular hepatocellular carcinomas: Usefulness of a test bolus in examination and subtraction imaging

Takahashi

Yoshioka

Yamaguchi

et al. 2003

Magnetic Resonance Imaging

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Purpose:To assess the impact of the accelerated dynamic MR imaging (ADMRI) approach using parallel imaging for detecting hypervascular hepatocellular carcinomas (HCCs) and to evaluate the usefulness of a test bolus in examination and subtraction imaging in this setting. Materials and Methods:Thirty patients with 135 HCCs underwent ADMRI using a two-dimensional gradient-recalled echo sequence with parallel imaging. Seventeen patients were evaluated without a test bolus and 13 patients with a test bolus. The detectability of HCCs was calculated between the groups with and without a test bolus. ADMRI was evaluated regarding the signal-to-noise ratio (SNR) of the lesion and the liver, the contrast-to-noise ratio (CNR) of the lesion vs. the liver, and the feasibility of subtraction images.Results: ADMRI with and without a test bolus had almost equal sensitivity (92.5% and 92.6%). No significant difference was seen in the SNR of lesions and the CNR of lesions vs. livers between both groups. With a test bolus, ADMRI could depict the peak enhancement of nodules on the 2nd or 3rd dynamic phases and optimized the timing of peak lesion enhancement. Subtraction images could be obtained regarding minimal slice misregistration. FOR ROUTINE EXAMINATIONS OF THE LIVER, precontrast and multi-phase dynamic CT and MR imaging are generally performed; scanning of the whole liver is needed, and requires about 20 -30 seconds to obtain one phase with a single breath-hold (1-7). Murakami et al (8) reported that double arterial phase CT imaging improved detection of hypervascular hepatocellular carcinomas (HCCs) and reduced false-positive lesions with multislice helical CT. However, since the radiation doses to patients are about 30%-50% greater with multislice helical CT as a result, primarily, of scan overlap, the radiation exposure from CT to patients is under discussion (9). ConclusionDynamic MR imaging with a parallel imaging technique can be performed without radiation exposure. Furthermore, the acquisition time can be about half that without parallel imaging (10,11). Using an array of multiple receivers, the parallel imaging technique allows reduction of the scan time in standard Fourier imaging by increasing the distance between sampling lines in k-space. The purpose of the present study was to assess the clinical feasibility of accelerated dynamic MRI (ADMRI) of the whole liver with parallel imaging in routine hepatic imaging, and to evaluate the usefulness of a test bolus in examination and subtraction imaging in this setting. MATERIALS AND METHODSThis study included 65 patients (48 males and 17 females; age range, 43-84 years; mean age, 66.2 years) referred to MR imaging between July, 2001 and April, 2002, with suspicion of having HCCs clinically or based on high levels of serum ␣-fetoprotein and/or proteins induced by vitamin K antagonist , or from the results of previous ultrasonography or helical CT. For 65 of these patients, 30 underwent pathologic examination or angiography after MRI examinations. Two patients underwe...

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Parallel acquisition techniques for accelerated volumetric interpolated breath‐hold examination magnetic resonance imaging of the upper abdomen: Assessment of image quality and lesion conspicuity

Vogt

Antoch

Hunold

et al. 2005

Magnetic Resonance Imaging

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Purpose:To evaluate the impact of parallel acquisition techniques (PATs) on image quality and detection of liver metastases using three-dimensional volumetric interpolated breath-hold examination (VIBE) for clinical liver imaging. Materials and Methods:Forty-nine patients with various primary malignancies underwent abdominal dynamic contrast-enhanced three-dimensional VIBE magnetic resonance imaging (MRI) (1.5 T) using a standard phased array coil. Recently introduced Generalized Autocalibrating Partially Parallel Acquisition (GRAPPA) and SENSitivity Encoding (mSENSE) PAT reconstruction algorithms were added to reduce scan time twofold. Overall image quality, motion, and aliasing artifacts were classified on a 5-point scale. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were performed for quantitative comparison. All sequences were evaluated concerning the number of detected lesions.Results: PAT resulted in a reduction of data acquisition time from 23 to 13 seconds. Both GRAPPA and mSENSE data sets yielded 30% less SNR (34.8 Ϯ 14.1 and 33.1 Ϯ 13.3, P Ͻ 0.001) and 35% less CNR (21.2 Ϯ 15.0 and 20.9 Ϯ 12.7, P Ͻ 0.05) in comparison to unaccelerated VIBE (SNR ϭ 50.8 Ϯ 20.3/CNR ϭ 32.5 Ϯ 19.1). Similarly, PAT revealed lower-image-quality scores than unaccelerated VIBE. GRAPPA resulted in more fold-over artifacts than mSENSE. mSENSE revealed slightly fewer motion artifacts than no PAT. The unaccelerated late-venous-phase VIBE sequence revealed 146 lesions in the same patients. Accelerated images with mSENSE reconstruction detected 138 lesions. GRAPPA revealed 127 lesions, and thus performed inferior to mSENSE. Conclusion:At least for arrays with small numbers of elements, such as arrays used in this study, the PATinduced reduction in scanning times must be weighed against compromises in image quality, which translate into poorer diagnostic performance regarding detection of small hepatic lesions. Thus, the PAT implementations tested in this study should probably be reserved for patients unable to hold their breaths for regular three-dimensional VIBE data sets.

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VIBE mit paralleler Akquisitionstechnik - eine neue Möglichkeit der dynamischen kontrastverstärkten MRT der Leber

Abstract: VIBE with iPAT allows MR imaging of the liver with high spatial and temporal resolution providing dynamic contrast-enhanced information about the whole liver. This may lead to improved detection of liver lesions, especially hepatocellular carcinoma.

Cited by 23 publications

References 4 publications

Automatic liver tumor diagnosis with Dynamic-Contrast Enhanced MRI

Automatic liver tumor diagnosis with Dynamic-Contrast Enhanced MRI

Accelerated dynamic MR imaging with a parallel imaging technique for hypervascular hepatocellular carcinomas: Usefulness of a test bolus in examination and subtraction imaging

Parallel acquisition techniques for accelerated volumetric interpolated breath‐hold examination magnetic resonance imaging of the upper abdomen: Assessment of image quality and lesion conspicuity

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