High-definition Fiber Tractography differentiates cingulate versus para-cingulate tumors

Introduction: Surgery for tumors involving the cingulum is challenging due to the functional relevance of the surrounding areas. Regular MRI/CT is unable to accurately differentiate tumors originating within the cingulum (limbic/paralimbic) versus adjacent to it (paracingulate/neocortical). High-definition fiber tractography (HDFT) has been proposed as a tool for pre-operative assessment of brain lesions.

Methods: We retrospectively evaluated the HDFT database at our institution. Eleven patients had tumors involving the cingulum. Lesions infiltrating and/or disrupting the cingulum were subclassified as cingulum resecting technique (CgRT), and those displacing it were subclassified as cingulum sparing technique (CgST). This subclassification was performed to identify patients in whom cingulum may be resected (CgRT) versus preserved (CgST).

Results: Eleven patients with tumors involving the cingulum were identified. Mean age was 45 years (24-68). Six (54.5%) tumors were left-sided and five (45.5%) right-sided. Pre-operative HDFT showed 4 (36.4%) tumors displacing (CgST), and 7 (63.6%) infiltrating/disrupting the cingulum (CgRT). Ten patients underwent to surgical resection (2 awake cases) and 1 patient underwent to CT-stereotactic biopsy. All CgST cases had preservation of the cingulum, of these, 3 (75%) had gross total resection (GTR) and 1 (25%) had subtotal resection (STR) due to positive intraoperative stimulation. Five (83.33%) CgRT patient had a GTR, and 1 (16.67%) STR. Nine (90%) patients had an uneventful postoperative period with improvement of their preoperative symptoms. One (10%) patient had postoperative transient aphasia and right-sided hemiparesis.

Conclusion : HDFT may allow maximal tumor resection with preservation of the cingulum bundle in cases where it is purely displaced. Development of new post-operative neurodeficit may be avoided when the surgical trajectory is chosen based on preoperative HDFT findings.