MAGNETIC-RESONANCE-IMAGING AND QUANTITATIVE-ANALYSIS OF INTRACRANIAL CYSTIC LESIONS - SURGICAL IMPLICATION

THE AUTHORS EVALUATED a series of proven intracranial cystic lesions p rospectively. The relative signal intensities of these lesions on both T1- and T2-weighted sequences were correlated with the composition an d viscosity of the cystic contents. Specimens were collected from 51 p atients by cyst aspiration or at the time of surgery. Once a specimen was obtained, it was immediately sent for quantitative analysis of pro teins, cholesterol, triglyceride, calcium, and blood by-products. In 3 0 patients, the cystic lesion was hypointense on T1 and hyperintense o n T2 relative to white matter. The cystic content in this group of pat ients was a watery fluid that could be easily aspirated. In another 14 patients, the cystic lesion was either isointense or hyperintense on T1 and hyperintense on T2-weighted sequences. In this group of patient s, the cystic contents were mild to moderately viscous and a wide bore needle or cannula was required for aspiration. In the remaining seven patients, the cystic contents were hyperintense (n = 4), isointense ( n = 2), or hypointense (n = 1) on T1 but all were markedly hypointense on T2-weighted sequences. The contents of the cystic lesions in these seven patients ranged from pastelike to solid and had to be removed s urgically. This study concludes that the observed T1- and T2-weighted signal intensities can predict the relative viscosity and the composit ion of intracranial cystic contents. This information is found to be q uite useful in planning surgery and using appropriate instrumentation in the management of intracranial cystic masses.