Rapidly progressive brain atrophy in septic ICU patients: a retrospective descriptive study using semiautomatic CT volumetry

Abstract

Background: Sepsis is often associated with multiple organ failure; however, changes in brain volume with sepsis are not well understood. We assessed brain atrophy in the acute phase of sepsis using brain computed tomography (CT) scans, and their findings' relationship to risk factors and outcomes.

Methods: Patients with sepsis admitted to an intensive care unit (ICU) and who underwent at least two head CT scans during hospitalization were included (n = 48). The first brain CT scan was routinely performed on admission, and the second and further brain CT scans were obtained whenever prolonged disturbance of consciousness or abnormal neurological findings were observed. Brain volume was estimated using an automatic segmentation method and any changes in brain volume between the two scans were recorded. Patients with a brain volume change < 0% from the first CT scan to the second CT scan were defined as the "brain atrophy group (n = 42)", and those with ≥ 0% were defined as the "no brain atrophy group (n = 6)." Use and duration of mechanical ventilation, length of ICU stay, length of hospital stay, and mortality were compared between the groups.

Results: Analysis of all 42 cases in the brain atrophy group showed a significant decrease in brain volume (first CT scan: 1.041 ± 0.123 L vs. second CT scan: 1.002 ± 0.121 L, t (41) = 9.436, p < 0.001). The mean percentage change in brain volume between CT scans in the brain atrophy group was -3.7% over a median of 31 days, which is equivalent to a brain volume of 38.5 cm3. The proportion of cases on mechanical ventilation (95.2% vs. 66.7%; p = 0.02) and median time on mechanical ventilation (28 [IQR 15-57] days vs. 15 [IQR 0-25] days, p = 0.04) were significantly higher in the brain atrophy group than in the no brain atrophy group.

Conclusions: Many ICU patients with severe sepsis who developed prolonged mental status changes and neurological sequelae showed signs of brain atrophy. Patients with rapidly progressive brain atrophy were more likely to have required mechanical ventilation.

Keywords: Atrophy; Brain; Critical care outcomes; Mechanical ventilation; Sepsis.

Conflict of interest statement

One author (Geoffrey Warnock) is an employee of PMOD Technologies Ltd. Only non-PMOD employees had control of inclusion of data and information.

© 2021. The Author(s).

Figures

Fig. 1

Flowchart of patients enrolled in the present study. Of 555 patients with sepsis managed from January 2015 to December 2020, 48 patients were enrolled

Fig. 2

Axial view of brain computed tomography (CT) scan of a 63-year-old man who was hospitalized and treated for 107 days for sepsis due to soft tissue infection. A and B are the first CT scan and C and D are the second CT scan of the patient. A and C are original brain CT scans and B and D are brain CT scans with a corresponding segmentation map where gray and white matter are colored red. Compared to the first CT scan (A), atrophy is evident on the second CT scan (C). Although small misclassifications are observed in the cerebellar vermis (arrows on B and D) and the right choroid plexus (white arrowhead on B), automatic segmentation was successful. Subtle beam-hardening artifact is found around the posterior fossa (red arrowheads on C),; it did not affect the classification. A 7.4% decrease in brain volume was calculated by the automatic algorithm

Fig. 3

Change in brain volume in the 42 cases in the brain atrophy group from the first computed tomography (CT) scan to the second CT scan