MR Imaging of Intracranial Calcification; Experimental and Clinical Studies

PURPOSE: This study was performed to evaluate MR signal intensity(SI) of calcification and to assess the capability of MRI in detection of various intracranial calcifications. MATERIALS AND METHODS: The MR findings and ROI value of experimental model of calcium carbonate suspension according to each concentration (20, 35, 50%) and diameter (1-10 mm) and hydroxyapatite suspension according to each concentration (10, 20, 30, 40, 50%) were analyzed. A specimen of calcification in cranio-pharyngioma was analyzed for its composition by XRD(X-ray diffractometer) and ICP(inductively coupled plasma) methods. MRI of 34 patients with intracranial calcifications were retrospectively analyzed for signal intensity of the calcification and its capability to detect calcifications according to size, location, and contrast with adjacent lesion. RESULTS: The calcium carbonate phantom with larger diameter and low concentration showed lower signal intensity on T2 than TlWl. Hydroxyapatite phantom showed high signal intensity in 10-30% concentration and low signal intensity in 40-50% concentration on T1 weighted image. The 5 cases of 34 intracranial calcifications showed high signal intensity on T1 weighted image. The capability of MRI in the detection of intracranial calcifications decreased in the circumstances such as small size(<2.5mm) and intraventricular location. Although the size of calcification was small, the detection was easy in the good contrast with adjacent lesion. However, the detection of the small sized calcification was easy if the contrast with adjacent lesion was good. CONCLUSION: lntracranial calcification shows generally low signal intensity on T1 and T2 weighted image with the exception of occasional high SI on TlWl. Detection of intracranial calcification in MRI is affected by its composition, size, location, and contrast with adjcent lesion.