Abnormal T₂-Weighted MRI Signal Surrounding Leads in a Subset of Deep Brain Stimulation Patients

Abstract

Background: Deep brain stimulation (DBS) surgery is a common treatment option for numerous neurological disorders. However, it is not without potential complications, such as hemorrhage and infection. Interestingly, we have observed several instances of abnormal T₂-weighted signal hyperintensity surrounding DBS leads on postoperative MRI that are not associated with hemorrhage or infection. Methods: To better characterize the incidence and timing associated with this finding, we retrospectively reviewed postoperative imaging for all DBS implants performed over 9 years at one institution. Results and Conclusions: Fifteen instances of T₂ signal hyperintensity surrounding DBS leads on postoperative MRI scans were observed across 239 implants (6.3% incidence) in 133 patients. The signal characteristics were most consistent with vasogenic edema, possibly representing an inflammatory response. The finding was typically unilateral, even in patients with simultaneous bilateral lead implants. Most affected patients were asymptomatic, although 3 were symptomatic and 1 experienced marked gait instability that was treated with steroids. T₂ signal abnormality was seen more commonly in scans obtained 3 or more days after surgery than in those collected immediately postoperatively. No differences in age, anatomical target, diagnosis, or number of microelectrode passes were noted between patients with or without T₂ signal. Further research will be needed to explain this curious neuroimaging finding, and to rule out cause for clinical concern.

Acute and Subacute Presentations of Cerebral Edema following Deep Brain Stimulation Lead Implantation

“…Although there have been multiple case reports and limited series in the literature [1,2,3,4,5] of such postoperative edematous cases, it remains an intriguing complication of which true etiology is unknown and is distinct from other more common complications such as hemorrhage, infection, or hardware-related issues that have been very well reported and characterized [6,7,8,9,10]. As described in the other reports [1,2,3,4,5], presentation is variable and independent of the underlying diagnosis or target. …”

“…Englot et al [2] were able to obtain postoperative MRIs on their patients after implantation and observed 15 of 239 electrodes implanted (6.3% incidence) to have associated T2-weighted hyperintensity; only 4 of all these electrodes (26% of those with edema, 1.6% overall) were associated with symptoms. Viewed differently, such T2-weighted signal abnormalities occurred in 14 of the 133 patients in their series (10.5%), as well as reported in other series without clinical correlation [12], which argues that perilead edema may be more of a common occurrence than reported.…”

“…Noninfectious, self-limiting postoperative cerebral edema around a deep brain stimulation (DBS) electrode is an uncommon complication infrequently reported in the medical literature [1,2,3,4,5]. The etiology of this clinical scenario remains unknown and is distinct from other more common complications such as hemorrhage, infection, or hardware-related issues that have been very well reported and characterized [6,7,8,9,10].…”

“…The etiology of this clinical scenario remains unknown and is distinct from other more common complications such as hemorrhage, infection, or hardware-related issues that have been very well reported and characterized [6,7,8,9,10]. Occurrence and presentation of symptoms vary, from subtle behavioral changes to lethargy and hemiplegia, presenting a few days postoperatively to several months later [1,2,3,4,5]. Imaging description and diagnosis also vary depending on the modality chosen, associated with increased T2 hyperintensity on MRI [2], contrast enhancement [5], or cystic cavitation on CT [4].…”

“…Occurrence and presentation of symptoms vary, from subtle behavioral changes to lethargy and hemiplegia, presenting a few days postoperatively to several months later [1,2,3,4,5]. Imaging description and diagnosis also vary depending on the modality chosen, associated with increased T2 hyperintensity on MRI [2], contrast enhancement [5], or cystic cavitation on CT [4]. …”