Abstract
Objective
Previous studies using advanced MRI techniques have documented abnormal transmantle bands connecting ectopic nodules to overlying cortex in patients with periventricular nodular heterotopia (PNH). We describe a similar finding using conventional MRI techniques.
Methods
Patients were identified by means of a full-text search of radiological reports. All scanning was performed using conventional sequences at 3T. Scans were reviewed by three neuroradiologists, and we characterized imaging features based on type of PNH and cortical irregularities associated with the transmantle band.
Results
A total 57 PNH patients were reviewed, of whom 41 demonstrated a ‘transmantle band’ connecting the nodule to the overlying cortex. One or more periventricular heterotopic nodule was present in all 41 patients – this was bilateral in 29/41 (71%) and unilateral in the remaining 29%. In many cases there was more than one such band, and in some cases this band was nodular. In 19 of the cases, the cortex which the band connected to was abnormal, showing thinning in 4 cases, thickening in 5 cases, and polymicrogyria in another 10.
Significance
The transmantle band can frequently be seen in both unilateral and bilateral cases of periventricular nodular heterotopia and can be visualized with conventional 3T MRI sequences. It highlights the underlying neuronal migration issues at play in the pathogenesis of this disorder, but it’s underlying role in the complex, patient-specific epileptogenic networks in this cohort has yet to be determined and warrants further investigation.
ABR