Early MRI findings in high grade glioma

Magnetic resonance imaging (MRI) is more sensitive than computerized tomogr aphy in the detection of many intracerebral lesions; however, the significa nce of some MRI findings may be unclear. Over four years, nine patients, ag ed 40-79 years, have been encountered whose initial MRI scans were negative or had minimal abnormalities and soon thereafter had high grade glioma. In itial MRI was performed in eight patients for new-onset seizures and one pa tient for a focal deficit. MRI was negative in four of the patients and mil dly abnormal in five of the patients (small areas of increased T2 and/or mi nimal enhancement). The initial diagnoses usually included inconclusive dif ferentials of stroke and infection with neoplasm less frequently considered . Radiographic progression leading to the diagnosis of high grade glioma be came evident on repeat MRI in 1-8 months with six patients showing progress ion within three months. All patients underwent surgery and had histologic diagnosis of glioma. Although MRI is quite sensitive, four of the initial s cans were negative with reasonable quality studies. Conversely, in five of the initial scans, the tumors were detected when so small that the radiogra phic findings were not typically diagnostic. Glioma must be considered as a possible cause of initial seizures or new neurologic deficits in adults wi th normal or minimally abnormal MRI. In this group, seizures were the overw helming hallmark of presentation. In such a clinical situation, close follo w-up with short interval repeat MRI should be performed.