The effect of Gd-DTPA on T(1)-weighted choline signal in human brain tumours.
ABSTRACT The influence of Gd-DTPA on T(1)-weighted (T(1)W) proton MR spectra has been investigated in 19 patients with histologically verified low (n = 13) or high-grade (n = 6) gliomas. Repeat measurements were performed on 9 patients (7 low-grade and 2 high-grade), with 28 examinations performed in total. Comparison of spectra obtained before and after 0.2 mmol/kg Gd-DTPA showed contrast agent induced broadening of the choline signal without significant signal area change. Lack of enhancement of the choline signal with the T(1)-weighted acquisitions implies that the contrast agent and the trimethylamine-containing species do not undergo significant direct interaction. Contrast agent induced changes in the choline signal observed in this and previous studies may, therefore, be attributable to T2*/susceptibility-based effects.
Article: CAN MAGNETIC RESONANCE SPECTROSCOPY ADEQUATELY DIFFERENTIATE NEOPLASTIC FROM NON-NEOPLASTIC AND LOW-GRADE FROM HIGH-GRADE LESIONS IN BRAIN MASSES?[show abstract] [hide abstract]
ABSTRACT: Objective: The aim of this study was to evaluate the usefulness of Magnetic Resonance Spectroscopy in the differential diagnosis of brain lesions. Materials and Methods: Forty-six patients with cerebral lesions were examined by Magnetic Resonance Spectroscopy. Choline, creatine, N-acetyl aspartate and lipid-lactate peaks were evaluated. Forty of the 46 patients underwent stereotactic biopsy or surgery. Histopathological results were compared with the Magnetic Resonance Spectroscopy results. Results: The Choline / N- acetyl aspartate ratio had the highest sensitivity (87.2%) in neoplastic versus nonneoplastic differentiation and the specificities of the Choline / Creatine, Choline / N-acetyl aspartate and Choline+Creatine / N-acetyl aspartate ratios were found to be 100%. Choline / Creatine ratios showed the highest sensitivity (95.7%) in low-grade versus high-grade differentiation and specificities of Choline / Nacetyl aspartate, Choline+Creatine / N- acetyl aspartate ratios and lipid-lactate levels were found to be 100%. Consequently, a value of Choline / Creatine > 2.2 and an accompanying lipid-lactate peak differentiated neoplasms as low-grade versus high-grade with a sensitivity of 100% (82.2-100%) and a specificity of 100% (71.7-100%). Conclusion: The presence of elevated Choline and decreased N-acetyl aspartate levels are effective in the differetiation of neoplastic versus non-neoplastic lesions with high sensitivity and specificity. A proposed ratio of Choline / Creatine > 2.2 and an accompanying lipid-lactate peak provide valuable information in differentiating low-grade from high-grade lesions. Keywords: Brain neoplasms, Magnetic resonance imaging, Magnetic resonance spectroscopy, Stereotactic biopsyMarmara Medical Journal 01/2010;
Article: Magnetic resonance spectroscopy of the breast at 3T: pre- and post-contrast evaluation for breast lesion characterization.[show abstract] [hide abstract]
ABSTRACT: To determine whether in vivo proton magnetic resonance spectroscopy at 3T can provide accurate breast lesion characterization, and to determine the effect of gadolinium on the resonance of tCho. Twenty-four positive-mammogram patients were examined on a 3T MR scanner. 1H-MRS was performed before and after gadolinium administration. tCho peak was qualitatively evaluated before and after contrast injection. Fourteen out of 27 lesions proved to be malignant after histopathological diagnosis. Using 1H-MRS, before contrast injection, 6/14 confirmed malignancies and 11/13 benign lesions were correctly classified; while, after contrast injection, 11/14 confirmed malignancies and 12/13 benign processes were correctly classified. Post gadolinium 1H-MRS proved useful in picking up tCho signal, improving the overall accuracy, sensitivity, and specificity by 35%, 83%, and 9%, respectively. 1H-MRS overall accuracy, sensitivity, and specificity in detecting breast lesion's malignancy were increased after gadolinium administration. It is prudent to perform 1H-MRS before contrast injection in large breast lesions to avoid choline underestimation. In cases of small or non-mass lesions, it is recommended to perform 1H-MRS after contrast injection for better voxel prescription to enable a reliable preoperative diagnosis.TheScientificWorldJOURNAL 01/2012; 2012:754380. · 1.66 Impact Factor