Radiological Evaluation Criteria for Chronic Subdural Hematomas : Review of the Literature

Correlating Age and Hematoma Volume with Extent of Midline Shift in Acute Subdural Hematoma Patients: Validation of an Artificial Intelligence Tool for Volumetric Analysis

OBJECTIVE

Decision for intervention in acute subdural hematoma patients is based on a combination of clinical and radiographic factors. Age has been suggested as a factor to be strongly considered when interpreting midline shift (MLS) and hematoma volume data for assessing critical clinical severity during operative intervention decisions for acute subdural hematoma patients. The objective of this study was to demonstrate the use of an automated volumetric analysis tool to measure hematoma volume and MLS and quantify their relationship with age.

METHODS

A total of 1789 acute subdural hematoma patients were analyzed using qER-Quant software (Qure.ai, Mumbai, India) for MLS and hematoma volume measurements. Univariable and multivariable regressions analyzed association between MLS, hematoma volume, age, and MLS:hematoma volume ratio.

RESULTS

In comparison to young patients (≤ 70 years), old patients (>70 years) had significantly higher average hematoma volume (old: 62.2 mL vs. young 46.8 mL, P < 0.0001), lower average MLS (old: 6.6 mm vs. young: 7.4 mm, P = 0.025), and lower average MLS:hematoma volume ratio (old: 0.11 mm/mL vs. young 0.15 mm/mL, P < 0.0001). Young patients had an average of 1.5 mm greater MLS for a given hematoma volume in comparison to old patients. With increasing age, the ratio between MLS and hematoma volume significantly decreases (P = 0.0002).

CONCLUSIONS

Commercially available, automated, artificial intelligence (AI)-based tools may be used for obtaining quantitative radiographic measurement data in patients with acute subdural hematoma. Our quantitative results are consistent with the qualitative relationship previously established between age, hematoma volume, and MLS, which supports the validity of using AI-based tools for acute subdural hematoma volume estimation.

Efficacy of intraoperative irrigation with artificial cerebrospinal fluid in chronic subdural hematoma surgery: study protocol for a multicenter randomized controlled trial

BACKGROUND

The surgical techniques for treatment of chronic subdural hematoma (CSDH), a common neurosurgical condition, have been discussed in a lot of clinical literature. However, the recurrence proportion after CSDH surgery remains high, ranging from 10 to 20%. The standard surgical procedure for CSDH involves a craniostomy to evacuate the hematoma, but irrigating the hematoma cavity during the procedure is debatable. The authors hypothesized that the choice of irrigation fluid might be a key factor affecting the outcomes of surgery. This multicenter randomized controlled trial aims to investigate whether intraoperative irrigation using artificial cerebrospinal fluid (ACF) followed by the placement of a subdural drain would yield superior results compared to the placement of a subdural drain alone for CSDH.

METHODS

The study will be conducted across 19 neurosurgical departments in Japan. The 1186 eligible patients will be randomly allocated to two groups: irrigation using ACF or not. In either group, a subdural drain is to be placed for at least 12 h postoperatively. Similar to what was done in previous studies, we set the proportion of patients that meet the criteria for ipsilateral reoperation at 7% in the irrigation group and 12% in the non-irrigation group. The primary endpoint is the proportion of patients who meet the criteria for ipsilateral reoperation within 6 months of surgery (clinical worsening of symptoms and increased hematoma on imaging compared with the postoperative state). The secondary endpoints are the proportion of reoperations within 6 months, the proportion being stratified by preoperative hematoma architecture by computed tomography (CT) scan, neurological symptoms, patient condition, mortality at 6 months, complications associated with surgery, length of hospital stay from surgery to discharge, and time of the surgical procedure.

DISCUSSION

We present the study protocol for a multicenter randomized controlled trial to investigate our hypothesis that intraoperative irrigation with ACF reduces the recurrence proportion after the removal of chronic subdural hematomas compared with no irrigation.

TRIAL REGISTRATION

ClinicalTrials.gov jRCT1041220124. Registered on January 13, 2023.

Predicting the progression of chronic subdural hematoma based on skull density

Objective

The objective of this study was to investigate potential correlations between skull density and the progression of chronic subdural hematoma (CSDH).

Methods

Patients with unilateral CSDH were retrospectively enrolled between January 2018 and December 2022. Demographic and clinical characteristics, as well as hematoma and skull density (Hounsfield unit, Hu), were collected and analyzed.

Results

The study enrolled 830 patients with unilateral CSDH until the resolution of the CDSH or progressed with surgical treatment. Of the total, 488 patients (58.80%) necessitated surgical treatment. The study identified a significant correlation between the progression of CSDH and three variables: minimum skull density (MiSD), maximum skull density (MaSD), and skull density difference (SDD) (p < 0.001). Additionally, in the multivariable regression analysis, MiSD, MaSD, and SDD were independent predictors of CSDH progression. The MiSD + SDD model exhibited an accuracy of 0.88, as determined by the area under the receiver operating characteristic curve, with a sensitivity of 0.77 and specificity of 0.88. The model's accuracy was validated through additional analysis.

Conclusion

The findings suggest a significant correlation between skull density and the CSDH progression.

The interdural hematoma: A subtype of convexity subdural/dural hematoma with specific radioanatomical characteristics

Background

Rare cases of biconvex hematomas splitting the convexity dura mater were reported and denominated interdural hematoma (IDH). Due to their rarity, little is known about their radiological characteristics, and in most cases, their invasive management with craniotomy and dural membrane excision is unnecessary.

Case Description

We report here a case of single burr-hole endoscopic evacuation of an IDH and its complete resolution after the 6-month follow-up imaging. The literature review reveals 11 reported cases of IDH. Most of them are male and the mean age is 65 years (range 51-90). Most of the reported IDHs were misdiagnosed as epidural hematoma or meningioma, and therefore, they have been managed invasively through craniotomy with dural excision. Diagnosis of the interdural nature was confirmed macroscopically during surgery in all cases and histology was reported for 6 cases. Image analysis found a double dural beak sign and biconvex shape on coronal planes, subarachnoid space enlargement at the collection extremities, and irregular thick inner wall as common radiological aspects of the IDH.

Conclusion

IDH is a rarely reported and often misdiagnosed dural hematoma subtype. Its invasive treatment through craniotomy is likely related to its unknown radiological characteristics. We review and raise awareness about potentially unique radiological anatomy that could avoid unnecessary invasive treatment. Moreover, we report the first case of endoscopically evacuated IDH with long-term follow-up imaging showing complete resolution.

Midline Shift in Chronic Subdural Hematoma : Interrater Reliability of Different Measuring Methods and Implications for Standardized Rating in Embolization Trials

OBJECTIVE

Evaluation of chronic subdural hematoma (cSDH) treatment success relies on radiologic measures, in particular hematoma volume, width and midline shift (MLS). Nevertheless, there are no validated standards for MLS measurement in cSDH. Aim of this study was to identify the most reliable measurement location and technique for MLS.

METHODS

Admission CT scans of 57 patients with unilateral cSDH were retrospectively analyzed. Axial slices were evaluated by 4 raters with MLS measurement in 4 locations, foramen of Monro (FM), thalamus (Th), mid-septum pellucidum (SP), maximum overall MLS (max) with 2 different techniques: displacement perpendicular to anatomical (ideal) midline (MLS-M), and displacement relative to the tabula interna in relation to the width of the intracranial space (MLS-T). Intraclass correlation coefficients (ICC) were calculated to assess interrater reliability and agreement of MLS‑M and MLS‑T measurement techniques. Measurements of cSDH volume and width were conducted for further data alignment.

RESULTS

The ICCs between readers were excellent (> 0.9) for all MLS‑M locations and for MLS-T_Th and ML-T_FM. The ICC was higher for MLS‑M than for MLS‑T in all locations. MLS-M_max showed the highest correlation coefficient of 0.78 with cSDH volume. Variance of MLS-M_max was explained in 64% of cases (adj. R squared) by cSDH volume based on a simple linear regression model. An increase of 10 ml cSDH volume resulted in an average increase of 0.8 mm MLS-M_max.

CONCLUSION

The MLS measurement in cSDH patients should be standardized, and due to its high interrater reliability, the MLS‑M technique should be preferred.