Volume and densities of chronic subdural haematoma obtained from CT imaging as predictors of postoperative recurrence: a prospective study of 107 operated patients

Abstract

Background: Chronic subdural haematoma (CSDH) is a common entity in neurosurgery with a considerable postoperative recurrence rate. Computerised tomography (CT) scanning remains the most important diagnostic test for this disorder. The aim of this study was to characterise the relationship between the recurrence of CSDH after treatment with burr-hole irrigation and closed-system drainage technique and CT scan features of these lesions to assess whether CT findings can be used to predict recurrence.

Methods: We investigated preoperative and postoperative CT scan features and recurrence rate of 107 consecutive adult surgical cases of CSDH and assessed any relationship with univariate and multivariate regression analyses.

Results: Seventeen patients (15.9 %) experienced recurrence of CSDH. The preoperative haematoma volume, the isodense, hyperdense, laminar and separated CT densities and the residual total haematoma cavity volume on the 1st postoperative day after removal of the drainage were identified as radiological predictors of recurrence. If the preoperative haematoma volume was under 115 ml and the residual total haematoma cavity volume postoperatively was under 80 ml, the probability of no recurrence was very high (94.4 % and 97.4 % respectively).

Conclusions: These findings from CT imaging may help to identify patients at risk for postoperative recurrence.

Fig. 1

The segmentation and annotation of fluid and air volumes in preoperative and postoperative CT scans. Upper row: preoperative images. Lower row: postoperative images. Curves to the far left show typical intensity histograms for important image contrasts: brain/haematoma fluid/residual rinsing fluid (red rectangle); skull/all other tissues (orange rectangle); air/all other tissues (blue rectangle). a Representative preoperative and postoperative image sets; b manual delineation (blue line) and semi-automatic seed-growing of air pockets (red fill); c appearance after region-growing-based fill-in to generate areas with fluid and air, left and right

Fig. 2

Representative CT densities of CSDHs according to the classification described by Nakaguchi et al. [17]. Upper row: densities of haematoma with high recurrence rate: a isodense; b hyperdense; c laminar; d separated. Lower row: densities of haematoma with low recurrence rate: e hypodense; f gradation; g trabecular

Fig. 3

Line plots of the maximum in-plane thickness of CSDH (mean and 95 % CI) assessed by CT scan throughout the study period in non-recurrent and recurrent cases from unilateral (blue lines) and bilateral (green lines) groups. The thickness of haematoma membrane at 3 mm is indicated with a separate black horizontal line

Fig. 4

Line plots of the maximum midline displacement (mean and 95 % CI) assessed by CT scan throughout the study period in non-recurrent and recurrent cases from unilateral (blue lines) and bilateral (green lines) groups

Fig. 5

Prognosis of postoperative no-recurrence of chronic subdural haematoma with respect to the distribution of preoperative and postoperative volumes. Green points non-recurrent cases; red points recurrent cases. Separate black horizontal lines indicate cut-off values. a The probability of no recurrence was estimated to 94.4 % (95 % CI 81.7–98.5) if the preoperative haematoma volume was under 115 ml. b The probability of no-recurrence was estimated to be 97.4 % (95 % CI 86.5–99.5) if the residual total haematoma cavity volume on the 1st postoperative day was under 80 ml