Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jun 2000
Comparative Study Clinical TrialQuantification of endothelial permeability, leakage space, and blood volume in brain tumors using combined T1 and T2* contrast-enhanced dynamic MR imaging.
This study describes a method for imaging brain tumors that combines T1-weighted (T1W) and T2*-weighted (T2*W) dynamic contrast-enhanced acquisitions. Several technical improvements have been made to produce high-quality three-dimensional mapping of endothelial permeability surface area product (k) and leakage space (vl), based on T1W data. Tumor blood volume maps are obtained from T2*W images with a complete removal of residual relaxivity effects. ⋯ Pixel-by-pixel comparison showed a strong correlation between rCBV and k in 11 of 15 patients. However, decoupling between pixel-wise rCBV and k was found in four patients who had lesions with moderate k and vl elevation but no increase of rCBV. Results from this study suggest that in assessing the angiogenic activities in brain tumors it is advisable to monitor simultaneously changes in tumor blood volume, vessel permeability, and leakage space of tumor neovasculature.
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J Magn Reson Imaging · Feb 2000
Breath-hold 3D gradient-echo MR imaging of the lung parenchyma: evaluation of reproducibility of image quality in normals and preliminary observations in patients with disease.
This study evaluates the reproducibility and image quality of a three-dimensional (3D) gradient-echo sequence for imaging the lung parenchyma, with and without gadolinium administration, using a 2D spoiled gradient-echo sequence for comparison. Twenty patients without lung disease (normals) and five patients with lung disease (lung disease) underwent paired 2D and 3D gradient-echo sequences, without contrast (24 patients) and with contrast (18 patients). Images were retrospectively reviewed independently in a blinded fashion by two investigators. ⋯ Infiltrates, lung cancer, and pulmonary metastasis were better shown on the gadolinium-enhanced 3D gradient-echo sequences than on the other sequences. Breath-hold 3D gradient-echo imaging results in good image quality and negligible image artifacts and is superior to 2D spoiled gradient-echo imaging. Preliminary results in patients with disease appear promising.
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J Magn Reson Imaging · Feb 2000
In vivo Hahn spin-echo decay (Hahn-T2) observation of regional changes in the time course of oleic acid lung injury.
We studied the time course of changes in the Hahn spin-echo decay (Hahn-T2) in lungs of spontaneously breathing living rats at 1 hour, 3 hours, and 7 days following oleic acid injection. Motion artifacts were minimized by using the motion-insensitive interleaved rapid line scan (ILS) imaging technique. Prior to injury, the lungs exhibited two resolvable exponential Hahn-T2 components. ⋯ The third, much longer, component is probably due to intraalveolar pulmonary edema. After 7 days the Hahn decay was similar to that observed before injury, probably reflecting resolution of the edema. Our data suggest that Hahn-T2 measurements can be used to characterize the time course and regional distribution of lung injury in living animals.
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We describe the magnetic resonance (MR) findings in patients with gastrointestinal polyposis syndromes using breath-hold T1-weighted sequences, both standard and with fat suppression, prior to and following gadolinium administration, and breathing-independent single-shot half-Fourier RARE T2-weighted sequences. Six patients with gastrointestinal polyposis syndromes underwent MR examination to investigate for the presence of metastatic disease. The appearances of the gastrointestinal polyps on noncontrast T1-weighted spoiled gradient-echo (SGE), T2-weighted (half-Fourier RARE) images, and early and late gadolinium-enhanced SGE images were determined. ⋯ Extra gastrointestinal findings included an adrenal adenoma (1 patient), a pheochromocytoma (1 patient), and liver metastases (2 patients). Gastrointestinal polyps in patients with polyposis syndromes may be visualized on MR images employing breath-hold T1-weighted and breathing-independent snapshot T2-weighted techniques. Appreciation of polyp enhancement on post-gadolinium images is an important finding, which should help distinguish polyps from bowel contents.
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J Magn Reson Imaging · Dec 1999
Stomach diseases: MR evaluation using combined t2-weighted single-shot echo train spin-echo and gadolinium-enhanced spoiled gradient-echo sequences.
The aim of this study was to describe the magnetic resonance (MR) appearances of diseases of the stomach using combined T1-weighted spoiled gradient-echo, T2-weighted single-shot echo train spin-echo and gadolinium-enhanced spoiled gradient-echo sequences. All patients with gastric diseases who underwent combined T2-weighted single-shot echo train spin-echo and gadolinium-enhanced conventional and fat-suppressed spoiled gradient-echo imaging between October 1, 1996 and March 1, 1999, and who had histological or other imaging proof of disease, were included in this study. This patient population was comprised of 40 patients with subsequently proven gastric abnormalities, including malignant tumors (25) or benign disease (15). ⋯ Magn. Reson. Imaging 10:950-960, 1999.