Neuroimaging in Tuberous Sclerosis Complex: 7T MRI Discloses a Much Larger Number of Tubers Than Conventional MRI

Tuberous sclerosis complex (TSC) is a multisystemic genetic disorder whose main neuropathologic features include cortical and subcortical tubers, believed to be the source of epileptogenesis. The main purpose of this study was to disclose the performance of 7T and conventional MRI in classifying and counting tubers, in 30 subjects with clinically confirmed TSC and TSC1 and TSC2 molecular analysis.

In subjects with TSC, performance of 7T and conventional brain MRI in counting and recognizing tuber types were analyzed and compared. Additionally, epilepsy status and molecular analysis data were evaluated and their relationship with tuber burden analyzed.

On average, 7T MRI detected 28 more tubers than 3T MRI and 32 more tubers than 1.5T MRI. 7T MRI detected significantly more type C tubers than 3T MRI (P < .001) and 1.5T MRI (P = .01). On 7T MRI, the group with active epilepsy had statistically significant higher total tuber counting than the groups with controlled epilepsy (P = .03) or without epilepsy (P = .03). There was no statistical difference among the 3 groups on conventional MRI. On 7T MRI, TSC2 subjects had significantly higher total tuber counts than those with TSC1 (P = .004), and the same was observed on conventional MRI (P = .001). On 7T MRI, subjects with TSC1 also had significantly higher tuber counts than those with no identified mutation (P < .001), which was not observed on conventional MRI (P = .07).

The capability of 7T MRI in detecting more tubers than conventional MRI may contribute to the understanding of the complexity of brain involvement in TSC, may help to delineate more precisely possible epileptogenic tubers, and to recognize lesions like tuber C, with a known link to epilepsy severity. Higher tubers count in the active epilepsy group and a significant correlation with TSC2 variants demonstrates the role of tuber load in epileptogenicity.