Diffusion MR imaging of giant cell tumors in tuberous sclerosis.

Giant cell tumors were studied by diffusion MR imaging in three patients with tuberous sclerosis. Diffusion MR imaging was performed on a 1.5-T unit with a gradient strength of 30 mT/m. b = 1000 seconds/mm2 images, and apparent diffusion coefficient (ADC) maps were studied. ADC values were recorded from ADC maps with particular care to obtain the values from the noncalcified regions of the giant cell tumors. ADC values of the normal brain parenchyma and hamartomas were also recorded by multiple evaluations. The ADC values in all three giant cell tumors (0.78, 0.92, and 0.92 x 10-3mm2/s) were within the ranges of the normal brain parenchyma (0.62-1.04 x 10-3mm2/s), and they were prominently less than those of parenchymal hamartomas (1.18-1.86 x 10-3mm2/s). The finding of ADC values of the noncalcified portions of the giant cell tumors being identical to those of normal brain parenchyma is consistent with the presence of normal molecular motion of water, hence relatively normal tissue integrity within these tumors. This was likely a reflection of benignity of these slowly growing tumors.