Cavum Septum Pellucidum in Retired American Pro-Football Players

Abstract

Previous studies report that cavum septum pellucidum (CSP) is frequent among athletes with a history of repeated traumatic brain injury (TBI), such as boxers. Few studies of CSP in athletes, however, have assessed detailed features of the septum pellucidum in a case-control fashion. This is important because prevalence of CSP in the general population varies widely (2% to 85%) between studies. Further, rates of CSP among American pro-football players have not been described previously. We sought to characterize MRI features of the septum pellucidum in a series of retired pro-football players with a history of repeated concussive/subconcussive head traumas compared with controls. We retrospectively assessed retired American pro-football players presenting to our memory clinic with cognitive/behavioral symptoms in whom structural MRI was available with slice thickness ≤2 mm (n=17). Each player was matched to a memory clinic control patient with no history of TBI. Scans were interpreted by raters blinded to clinical information and TBI/football history, who measured CSP grade (0-absent, 1-equivocal, 2-mild, 3-moderate, 4-severe) and length according to a standard protocol. Sixteen of 17 (94%) players had a CSP graded ≥2 compared with 3 of 17 (18%) controls. CSP was significantly higher grade (p<0.001) and longer in players than controls (mean length±standard deviation: 10.6 mm±5.4 vs. 1.1 mm±1.3, p<0.001). Among patients presenting to a memory clinic, long high-grade CSP was more frequent in retired pro-football players compared with patients without a history of TBI.

Keywords: concussion; magnetic resonance imaging; septum pellucidum; traumatic brain injury.

FIG. 1.

Cavum septum pellucidum (CSP) grading diagrams and CSP grade and length for each patient. (A) The initial measurements that were taken in the midsagittal plane. The solid horizontal line depicts the longest intraventricular distance from genu to splenium of the corpus callosum (termed “septal length”). All images were then reformatted such that the coronal axis was perpendicular to this line to optimize coronal measurements along the septum. The dashed vertical line depicts the most anterior aspect of the columns of the fornix. This line was used to distinguish between the pre-fornix septum (where separations of the leaves of the septum pellucidum are termed CSP) and the post-fornix septum (where separations of the leaves of the septum pellucidum are termed “cavum vergae” [CV]). (B) A reformatted coronal MRI image for one patient that shows the greatest evidence of separation of the leaves of the septum pellucidum. This view was used to perform CSP grading for each patient. The dashed box depicts the region that is then enlarged to illustrate “Grade 2” in panel B. (C) Enlarged views of representative T1 coronal images for each CSP grade. Note that the Grade 0 septum appears crisp without any evidence of cyst (CSP absent). Grade 1 septum shows slight interior hypointensity that is not, however, clearly CSF signal intensity (septum unclear/CSP equivocal). Grades 2–4 show clear evidence of CSF signal between the separated leaves of the septum pellucidum. The degree of separation between the leaves of the septum pellucidum is then used to assign a grade of 2–4: Grade 2 CSP is not wider than the septum, Grade 3 CSP is wider than the septum but less than half the intraventricular width, and Grade 4 CSP is greater than half the intraventricular width. (D) CSP grade and length for each patient. Manual horizontal jitter was added to overlapping “grade” values in the graph to improve visibility.