Journal of magnetic resonance imaging : JMRI
-
J Magn Reson Imaging · Jun 2007
Three-dimensional gradient-echo imaging for percutaneous MR-guided laser therapy of liver metastasis.
To evaluate the use of three-dimensional (3D) gradient-echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR-guided catheter placement for laser therapy of liver metastases. ⋯ 3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis.
-
To evaluate the impact of data quality on the localization of brain activation in functional magnetic resonance imaging (fMRI) and to explore whether the temporal contrast-to-noise-ratio (CNR) provides a quantitative parameter to estimate fMRI quality. ⋯ Calculating the CNR using an adaptive low-pass filter gives similar results to a GLM-based approach and could be advantageous for cases in which the hemodynamic response function (HRF) differs significantly from common assumptions. The CNR can be used to identify and exclude runs with suboptimal CNR, and to identify sessions with insufficient data quality. The CNR may serve as a quantitative and intuitive parameter to assess the performance and quality of clinical fMRI investigations, including information on both functional performance (contrast) and data quality (noise caused by the system and physiology).
-
J Magn Reson Imaging · Jun 2007
Contrast-dose relation in first-pass myocardial MR perfusion imaging.
To determine the regime of linear contrast enhancement in human first-pass perfusion cardiovascular magnetic resonance (CMR) imaging to improve accuracy in myocardial perfusion quantification. ⋯ Quantitative evaluation of cardiac MR perfusion data needs to account for signal saturation in both the LV blood pool and the myocardium.
-
J Magn Reson Imaging · Jun 2007
Comparative StudyComparison of biphasic and reordered fat suppression for dynamic breast MRI.
To optimize a reordered k-space acquisition that applies intermittent fat saturation (FS) pulses to allow for a time-efficient reduction of fat signal in breast MR images, and compare it with an elliptic-centric biphasic FS method in terms of the degree of fat suppression and speed. ⋯ This method will allow robust fat suppression with virtually no extension in imaging time for dynamic contrast-enhanced (DCE)-MRI.
-
J Magn Reson Imaging · Jun 2007
Clinical aspects of the apparent diffusion coefficient in 3He MRI: results in healthy volunteers and patients after lung transplantation.
To measure the apparent diffusion coefficient (ADC) after inhalation of hyperpolarized (3)He in healthy volunteers and lung transplant recipients, and demonstrate the gravity dependence of ADC values. ⋯ An anterior-posterior (A/P) gradient was found in inspiration and expiration in healthy lungs. Healthy, transplanted, and native diseased lungs had significantly different mean ADC values. From our preliminary results, (3)He MRI appears to be sensitive for detecting areas of abnormal ventilation in transplanted lungs.