[Diffusion-weighted image in the study of brain tumors and peritumoral edema]

The informative value of the technique of diffusion-weighted images (DWI) and diffusion maps was studied in diagnosing supratentorial tumors of the brain. Sixty four patients were examined. Among them there were 35 patients with glial brain neoplasms of varying malignancy [benign astrocytomas (asc) in 15 patients, anaplastic asc in 10, and glioblastomas in 10)], 15 patients with meningiomas, 5 with hydrocephalus, 9 with cerebral circulatory disorders. To obtain DWI, diffusion-weighted echo-planar impulse sequence was used. ADC was within (1.52 +/- 0.34) x 10(-3) mm2/sec for fibrillary astrocytomes. The anaplastic astrocytoma group showed variations in ADC values: ADC was higher in the contrasted part of the tumor than in the non-contrasted one and averaged (1.23 +/- 0.32) x 10(-3) mm2/sec. Glioblastomas were also noted for a higher variation in ADC that averaged (1.18 +/- 0.29) x 10(-3) mm2/sec. Meningiomas had a greater MR signal in response to DWI and low ADC values [(0.97 +/- 0.17) x 10(-3) mm2/sec]. Particular emphasis is laid on the study of different types of brain edema. ADC in the area of vasogenic (peritumoral), cytotactic (ischemic), and interstitial edema was (1.30 +/- 0.11) x 10(-3), (1.04 +/- 0.05) x 10(-3), and (1.91 +/- 0.1) x 10(-3) mm2/sec, respectively (p < 0.05) and sharply distinct in ADC maps.