Practical one-dimensional measurements of age-related brain atrophy are validated by 3-dimensional values and clinical outcomes: a retrospective study

Abstract

Background: Age-related brain atrophy has been represented by simple 1-dimensional (1-D) measurements on computed tomography (CT) for several decades and, more recently, with 3-dimensional (3-D) analysis, using brain volume (BV) and cerebrospinal fluid volume (CSFV). We aimed to show that simple 1-D measurements would be associated with 3-D values of age-related atrophy and that they would be related to post-traumatic intracranial hemorrhage (ICH).

Methods: Patients ≥60 years with head trauma were classified with central atrophy (lateral ventricular body width >30 mm) and/or cortical atrophy (sulcus width ≥2.5 mm). Composite atrophy was the presence of central or cortical atrophy. BV and CSFV were computed using a Siemens Syngo workstation (VE60A).

Results: Of 177 patients, traits were age 78.3 ± 10, ICH 32.2%, central atrophy 39.5%, cortical atrophy 31.1%, composite atrophy 49.2%, BV 1,156 ± 198 mL, and CSFV 102.5 ± 63 mL. CSFV was greater with central atrophy (134.4 mL), than without (81.7 mL, p < 0.001). BV was lower with cortical atrophy (1,034 mL), than without (1,211 mL; p < 0.001). BV was lower with composite atrophy (1,103 mL), than without (1,208 mL; p < 0.001). CSFV was greater with composite atrophy (129.1 mL), than without (76.8 mL, p < 0.001). CSFV÷BV was greater with composite atrophy (12.3%), than without (6.7%, p < 0.001). Age was greater with composite atrophy (80.4 years), than without (76.3, p = 0.006). Age had an inverse correlation with BV (p < 0.001) and a direct correlation with CSFV (p = 0.0002) and CSFV÷BV (p < 0.001). ICH was greater with composite atrophy (49.4%), than without (15.6%; p < 0.001; odds ratio = 5.3). BV was lower with ICH (1,089 mL), than without (1,188 mL; p = 0.002). CSFV÷BV was greater with ICH (11.1 %), than without (8.7%, p = 0.02). ICH was independently associated with central atrophy (p = 0.001) and cortical atrophy (p = 0.003).

Conclusions: Simple 1-D measurements of age-related brain atrophy are associated with 3-D values. Clinical validity of these methods is also supported by their association with post-injury ICH. Intracranial 3-D software is not available on many CT scanners and can be cumbersome, when available. Simple 1-D measurements, using the study methodology, are a practical method to objectify the presence of age-related brain atrophy.

Keywords: Brain atrophy; CT imaging; Traumatic intracranial hemorrhage.

Fig. 1

1-Dimensional Measurements. Transverse distance “A-to-B” is the maximum lateral ventricle body width; “C” is ≥ 2 cortical sulci, measuring ≥2.5 mm each; and transverse distance “D-to-E” is the intracranial width (at the level of “A-to-B”)

Fig. 2

3-Dimensional Measurements. The 3-dimensional measurements were obtained from the level of the skull vertex and caudal to the level of the foramen magnum

Fig. 3

3-D Threshold Fields. a highlighting of brain parenchyma (Hounsfield range 22-55); b highlighting of CSF (Hounsfield range 0-15)

Fig. 4

3-D Threshold Fields. a highlighting of brain parenchyma (Hounsfield range 22-55); b highlighting of CSF (Hounsfield range 0–15). Brain volume contamination in patient with extra-cranial hematoma (a: white arrow)