Computed tomography-guided navigated transcranial magnetic stimulation for preoperative brain motor mapping in brain lesion resection: A case report

Abstract

Background: Navigated transcranial magnetic stimulation (nTMS) is a well establish a noninvasive method for preoperative brain motor mapping. We commonly use magnetic resonance imaging (MRI) to supply the nTMS system. In some cases, MRI is not possible or available, and the use of computed tomography (CT) is necessary. We present the first report describing the association of CT and nTMS motor mapping for brain lesion resection. Case Description: CT imaging of a 59-year-old man suffering from acquired immune deficiency syndrome for 17 years, presenting with seizure and right hemiparesis, revealed a small single hypodense ring-enhancing lesion in the left central sulci suggesting cerebral toxoplasmosis. After 3 weeks of neurotoxoplasmosis treatment, due to four consecutive tonic-clonic seizures, a new CT scan was performed and showed no lesion changes. MRI was in maintenance at that time. Infectious diseases department suggested a brain lesion biopsy. Due to lesion’s location, we decided to perform a presurgical nTMS motor mapping. After a small craniotomy, we could precisely locate and safely totally remove the lesion. The pathology report revealed a high suspicious toxoplasmosis pattern. The patient was discharged after 2 days and continued toxoplasmosis treatment. After 6 months follow-up, he showed no signs of any procedure-related deficits or radiological recurrence. Conclusion: We report the feasibility and applicability of nTMS motor mapping using CT scan as an image source. It gives neurosurgeons another possibility to perform motor mapping for brain lesion removal, especially when MRI is not available or feasible.

Navigated TMS in the ICU: Introducing Motor Mapping to the Critical Care Setting

“…Therefore, to enable widespread use of nTMS motor mapping in the ICU, we realized that CT must be adapted and validated as the basis for neuronavigation. Using CT for this purpose has previously only been described in a singular recent case which did not address possible navigation discrepancies between CT and MRI [ 31 ]. By preprocessing CT scans with a slice thickness of 2 mm, we were able to generate usable head models suited for patient co-registration ( Figure 1 ).…”

Mapping of Motor Function with Neuronavigated Transcranial Magnetic Stimulation: A Review on Clinical Application in Brain Tumors and Methods for Ensuring Feasible Accuracy

“…In a special environment such as the intensive care unit with critically ill patients, an approach for safe and reliable use of nTMS motor mapping has been described recently, yet preliminarily in patients suffering from other diseases than brain tumors (e.g., central cord syndrome after trauma, ischemic or hemorrhagic stroke) [ 91 ]. In particular, the use of computed tomography (CT) instead of MRI data may help to establish nTMS motor mapping also in special environments with patients who may only be eligible to undergo CT due to specific infrastructural constraints (e.g., non-availability of timely imaging by MRI) or medical conditions (e.g., specific implanted devices as contraindications for MRI) [ 91 , 92 ]. While this underlines the broad applicability of nTMS motor mapping, which requires little patient interaction while creating valuable data on the motor system in a non-invasive way, high accuracy has to be ensured and other imaging sources than MRI have to be regarded as second-line alternatives in selected cases.…”