Preoperative imaging findings in patients undergoing transcranial magnetic resonance imaging-guided focused ultrasound thalamotomy

Abstract

The prevalence and impact of imaging findings detected during screening procedures in patients undergoing transcranial MR-guided Focused Ultrasound (tcMRgFUS) thalamotomy for functional neurological disorders has not been assessed yet. This study included 90 patients who fully completed clinical and neuroradiological screenings for tcMRgFUS in a single-center. The presence and location of preoperative imaging findings that could impact the treatment were recorded and classified in three different groups according to their relevance for the eligibility and treatment planning. Furthermore, tcMRgFUS treatments were reviewed to evaluate the number of transducer elements turned off after marking as no pass regions the depicted imaging finding. A total of 146 preoperative imaging findings in 79 (87.8%) patients were detected in the screening population, with a significant correlation with patients’ age (rho = 483, p < 0.001). With regard of the group classification, 119 (81.5%), 26 (17.8%) were classified as group 1 or 2, respectively. One patient had group 3 finding and was considered ineligible. No complications related to the preoperative imaging findings occurred in treated patients. Preoperative neuroradiological findings are frequent in candidates to tcMRgFUS and their identification may require the placement of additional no-pass regions to prevent harmful non-targeted heating.

The Role of Treatment-Related Parameters and Brain Morphology in the Lesion Volume of Magnetic-Resonance-Guided Focused Ultrasound Thalamotomy in Patients with Tremor-Dominant Neurological Conditions

“…Indeed, in order to achieve long-lasting clinical effects, an appropriately sized lesion must be achieved [4]. The different amounts of supplied acoustic energy required to produce a lesion in the brain via MRgFUS vary across patients, depending on the acoustic properties and the density of every single intervening tissue (white matter, gray matter, and cerebral spinal fluid), which influences the amount of energy carried by the acoustic wave that is transmitted rather than reflected or absorbed [5][6][7]. The skull bone is the main barrier for ultrasounds traversing the brain, and its inter-subject variability in thickness and density represents one of the main features leading to the heterogeneous magnitude of the applied acoustic power and treatment time.…”

Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study

“…Over recent years, Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy has become an attractive treatment for medically intractable tremor due to Essential Tremor (ET) or Parkinson’s Disease (PD); the technique shows clinical effectiveness with minimal invasiveness compared to other treatments [ 1 , 2 , 3 , 4 , 5 , 6 ]. With accumulating experience and research, many critical aspects of MRgFUS have significantly evolved, namely patient selection criteria, surgical targeting, and technique optimization [ 7 , 8 , 9 , 10 , 11 , 12 ]. In addition, a growing number of studies using long-term follow-up have focused on the possibility of relapse after treatment.…”

“…Some of the experiences published so far have explored the correlation between tremor improvement and certain technical and patient-related factors, trying to weight the impact of these factors on tremor improvement [ 13 , 17 , 18 , 19 ]. An important role is also recognized in MRI imaging, both in terms of treatment planning and potential prognostic value [ 12 , 20 ].…”

Characteristics of Pain During MRI-Guided Focused Ultrasound Thalamotomy

“…Head pain during sonication is common, and in some cases, the treatment has to be aborted because of severe pain. 22-24 Despite the administration of analgesics such as nonsteroidal anti-inflammatory drugs, acetaminophen, or at some institutes, dexamethasone, 22,25,26 pain is not always well controlled. The location and severity of the pain vary across patients, and it is difficult for physicians to imagine the type of pain provoked by high-energy ultrasound sonication.…”

“…1,2,6,9,[12][13][14][15][16][17][18][19][20][21] Head pain during sonication is common, and in some cases, the treatment has to be aborted because of severe pain. [22][23][24] Despite the administration of analgesics such as nonsteroidal anti-inflammatory ABBREVIATIONS: CRST, clinical rating scale for tremor; MRgFUS, magnetic resonance imaging-guided focused ultrasound; NRS, numerical rating scale; SDR, skull density ratio; SF-MPQ2, Short-Form McGill Pain Questionnaire 2; VIM, ventral intermediate. Supplemental digital content is available for this article at neurosurgery-online.…”