Does magnetic resonance imaging induce tissue damage due to DBS lead heating?

Abstract

Dear Sir, Deep brain stimulation (DBS) is an effective and approved surgical treatment for advanced Parkinson’s disease (PD). MRI is routinely used in the postoperative period to document correct electrode position and to access for complications, such as haemorrhage. However, with over 75,000 patients treated worldwide, the safety of MRI in patients with DBS devices continuous to be debated [2, 7]. Several reports documented adverse events while performing MRI scans in patients with implanted DBS hardware [1, 3–6, 8, 9]. We present and discuss a case of an asymptomatic patient, who presented abnormal MRI findings alongside the implanted DBS lead. The 67-year-old male patient had right STN DBS for refractory Parkinson’s disease (PD). Tremor and rigidity in the left extremities caused a significant limitation of daily activities. Postoperative brain CT scan and brain MRI showed correct electrode positioning and the absence of surgical complications. One year after the right STN electrode implantation, the patient presented progressive disabling symptoms in his right extremities. We decided to perform a second electrode implantation in the left STN. A preoperative brain MRI was performed for surgical planning. The internal pulse generator (IPG) was switched off before scanning. Lead implantation occurred in the left STN. A routine postoperative brain T2weighted MRI sequences showed the presence of a hyperintense signal, but along the course of the right DBS lead, mostly around the tip of the electrode (Fig. 1). The right electrode was in place. The patient did not present any clinical signs or symptoms. Laboratory examinations were within the normal range. The abnormal MRI signal was assumed to be oedema. No treatment was given. At 3-months follow-up, the patient presented without any neurological deficit in his left limbs. A literature review revealed several recent studies describing a similar phenomenon [1, 4, 5, 8, 9]. Zrinzo et al. [9] from London reported a case of oedema around the implanted leads noted on nonstereotactic MRI made 2 days after surgery. The authors suspected the abnormal MRI signal to be secondary to head movement during the immediate postoperative stereotactic MRI. Lefaucheur et al. [4] from France reported 10 days after bilateral STN DBS hyperintensity on MRI along the implanted leads in an acutely confused patient. Laboratory results were normal. The diagnosis of transient, symptomatic, noninfectious postoperative oedema was made. Oral corticosteroids resolved clinical and imaging findings after 3 weeks. Equally, Englot et al. [1] from California observed, in 15 out of 133 patients, hyperintense alterations surrounding DBS leads. The imaging findings were noted on delayed MRI scans (3 or more days after surgery), interestingly presenting unilaterally in patients usually implanted bilaterally. The authors assumed vasogenic oedema, secondary to an inflammatory response, to be responsible for the altered imaging findings. This article is not under review by any other journal and was not published in any part by another journal.