Lipid signal in evaluation of intracranial meningiomas / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Using magnetic resonance imaging, diagnosis of malignant meningioma from benign meningioma with atypical features is uncertain. We evaluated the value of lipid signal in differentiating intracranial meningiomas.</p><p><b>METHODS</b>1H-magnetic resonance spectroscopy (MRS) using a point resolved spectroscopy (TR/TE 1000/144 ms) sequences were performed on 34 patients on a 3.0 T scanner. Lipid peak located at 1.3 ppm was evaluated. MRS data from these tumours were compared with histopathological findings (including hematoxylin and eosin staining and KP-1 staining).</p><p><b>RESULTS</b>Twenty-nine meningiomas were histologically benign (eleven meningothelial, thirteen fibrous, four transitional and one microcystic), three were atypical, and two were anaplastic. Lipid signal was detected in ten cases: two anaplastic, three atypical, two fibrous and three meningothelial meningiomas. All voxels with lipid peak in the spectrum from the tumour were evaluated. With creatinine peak in the normal white matter chosen as internal standard, lipid/creatinine ratios of anaplastic, atypical and benign meningiomas were 0.844 +/- 0.027 (range from 0.725 to 0.994), 0.465 +/- 0.023 (range from 0.239 to 0.724), and 0.373 +/- 0.016 (range from 0.172 to 0.571) respectively. Highly significant differences were noted between anaplastic and the other two subtypes. Patchy necrosis was observed in anaplastic meningioma, while focal necrosis was noted in atypical meningioma with HE stain. However, no necrosis was found in benign group. KP-1 stain demonstrated histocytes containing lipids in the necrotic region of anaplastic and atypical meningioma.</p><p><b>CONCLUSION</b>The lipid signal at 1.3 ppm is a useful marker in evaluating the malignancy of intracranial meningiomas, especially in the differential diagnosis of anaplastic meningioma.</p>

Diagnostic value of contrast-enhanced fluid-attenuated inversion-recovery MRI for intracranial tumors in comparison with post-contrast T1W spin-echo MRI / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Contrast-enhanced fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) has been reported to have higher sensitivity for detecting leptomeningeal disease compared with contrast-enhanced T1-weighted MRI (CE T1WI). However, currently there are no studies showing the potential value of clinical applications of contrast-enhanced FLAIR (CE FLAIR) sequence in diagnosing intracranial tumors in a larger group of patients. The purpose of this study was to evaluate the diagnostic value of CE FLAIR in comparison with CE T1WI for intracranial tumors and to provide more information for clinical diagnosis and therapy.</p><p><b>METHODS</b>One hundred and four consecutive cases of intracranial tumors referred for CE brain MRI were analyzed with regard to FLAIR and T1WI pre- and post-administration of Gd-DTPA. The CE FLAIR and CE T1WI were evaluated independently by two radiologists for the number of examinations with one or more enhanced lesions, the number and location of enhanced lesions per examination, signal-to-noise ratio (SNR) and contrast-enhancement ratio (CER) of lesions, as well as the size and extent of the enhanced lesions.</p><p><b>RESULTS</b>In 98 of 104 cases, enhanced lesions were seen both on the FLAIR and T1W images. More lesions were seen on CE T1WI (n = 120) than those on CE FLAIR sequence (n = 117), but no differences of statistical significance were found between the two sequences (P > 0.05). Four lesions were revealed only on the CE FLAIR images whereas 7 lesions were only found on CE T1WI. Enhanced lesions located in the cerebral hemisphere or the forth ventricle were revealed much more on CE T1WI than on CE FLAIR images. However, CE FLAIR images may be useful in showing superficial abnormalities and those located in the sulcus or lateral ventricle. The CER and contrast-to-noise ratio (CNR) on CE T1WI was significantly higher (t = 7.10, P = 0.00; t = 9.67, P = 0.00, respectively), but grey matter/white matter contrast was lower (t = 2.46, P = 0.02) than those on CE FLAIR images. The SNR did not show any statistically significant difference between the two sequences (t = 1.1, P = 0.27). The size and extent of lesions on the CE FLAIR images were significantly larger than those on CE T1WI (t = 4.13, P = 0.00).</p><p><b>CONCLUSIONS</b>CE FLAIR and CE T1WI may complement each other in showing intracranial tumors and the CE FLAIR sequence should be selected as a routine MRI sequence.</p>

Evaluation of brain metastases with dynamic susceptibility-contrast MR imaging / 中华放射学杂志

Objective To study the characteristics of dynamic susceptibility-contrast(DSC)MR perfusion curves,color images and perfusion values in pre-operative brain metastasis.Methods Twenty- eight brain metastases underwent DSC MR perfusion imaging by using a first-pass T_2~* echo-planar sequence. The patients' data were transferred to on-line workstation.Time-signal intensity curves,color perfusion maps and rCBV,rMTT values in both tumor parenchyma and peri-tumor edema were analyzed,and independent t- test was used and P0.05).Conclusion Different originated brain metastases have nearly same characteristics in DSC MR perfusion imaging.