Value of dynamic MRI imaging in pituitary adenomas Indrajit I K, Chidambaranathan N, Sundar K, Ahmed I – Indian J Radiol Imaging

Objectives : MRI has proven to be the best imaging modality in the evaluation of pituitary tumors. Dynamic Imaging is technically a new tool, which has emerged with lot of promise in the evaluation of pituitary adenomas, particularly in accurate delineation of those microadenomas with no contour abnormality and in differentiating residual/recurrent adenoma from surrounding post operative tissue. Dynamic MR imaging is not only useful in the evaluation of pituitary microadenomas but has an equally important role in the assessment of macroadenoma as well. This study analyses and reviews the value of dynamic MR Imaging in pituitary adenomas and postoperative pituitary tumors.

Materials and Methods : A prospective MR Study was undertaken in twenty-five consecutive patients with suspected pituitary adenomatous lesions. These patients were subjected to dynamic MR imaging at our Department from Jan 1997 to Dec 1998. The study was performed on a 0.5T super conducting MR imaging system with Fast Spin echo technique. Gadodiamide (0.1 mmol/Kg) was administered over sixty seconds by hand injection. Dynamic coronal images were obtained simultaneously from three different portions of the gland. Fifteen images were obtained from each of the three portions at an interval of twenty to thirty seconds between the images.

Result : Dynamic MRI was performed in nineteen patients with microadenoma and six cases of macroadenoma. Dynamic MRI study was of diagnostic value in comparison with routine contrast MRI in eleven of the nineteen patients. Dynamic study did not add to the diagnosis and was merely of confirmatory value in remaining eight patients. Dynamic MRI study was used to identify the optimal time for delineation of the adenomatous tumor, by virtue view of the simultaneous differential contrast enhancement patterns between normal pituitary gland and adenoma. Further the enhancement pattern of the normal pituitary gland, the adenomatous nodule and the optimal delineation were individually assessed. This evaluation revealed the average time in seconds for onset of enhancement and the peak enhancement of normal pituitary gland were 43.1 and 111.9 seconds respectively. In comparison the pituitary adenomatous nodules exhibited an average time of 105.8 seconds for onset of enhancement and 188.1 seconds for peak enhancement. The average time in seconds for optimal tumor delineation was 93.9 seconds.

Conclusion : Dynamic MR Imaging has emerged as a technically refined tool in the evaluation of pituitary adenomas. The key questions in evaluation of pituitary adenomas include the presence or absence of a tumor, the number, the location of adenoma nodule, the invasive effects on adjacent structures and the post therapy status of adenoma. Clearly, dynamic MR Imaging is the foremost imaging modality answering these vital questions in patients with pituitary adenomas.

via Value of dynamic MRI imaging in pituitary adenomas Indrajit I K, Chidambaranathan N, Sundar K, Ahmed I – Indian J Radiol Imaging.

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