Various magnetic resonance imaging patterns of chronic subdural hematomas: indicators of the pathogenesis?

ARISE I Consensus Statement on the Management of Chronic Subdural Hematoma

ARISE (Aneurysm/AVM/cSDH Roundtable Discussion With Industry and Stroke Experts) organized a one-and-a-half day meeting and workshop and brought together representatives from academia, industry, and government to discuss the most promising approaches to improve outcomes for patients with chronic subdural hematoma (cSDH). The emerging role of middle meningeal artery embolization in clinical practice and the design of current and potential future trials were the primary focuses of discussion. Existing evidence for imaging, indications, agents, and techniques was reviewed, and areas of priority for study and key questions surrounding the development of new and existing treatments for cSDH were identified. Multiple randomized, controlled trials have met their primary efficacy end points, providing high-level evidence that middle meningeal artery embolization is a potent adjunctive therapy to the standard (surgical and nonsurgical) management of neurologically stable cSDH patients in terms of reducing rates of disease recurrence. Pooled data analyses following the formal conclusion and publication of these trials will form a robust foundation upon which guidelines can be strengthened for cSDH treatment modalities and optimal patient selection, as well as delineate future lines of investigation.

MRI appearance of chronic subdural hematoma

Objective

We aimed to describe the magnetic resonance imaging (MRI) characteristics of chronic subdural hematoma (cSDH) and to ascribe MRI patterns.

Methods

A total of 20 patients having 27 subdural hematomas underwent contrast-enhanced (CE) MRI of the brain at our institution between April 2019 and May 2021. The images were independently evaluated by two experienced neuroradiologists with regard to imaging characteristics on T1w, T2w, T2*-GRE, FLAIR, diffusion-weighted magnetic resonance imaging (DWI), and CE images.

Results

The signal characteristics of cSDH on T1- and T2-weighted images were rather heterogeneous. The majority of hematomas (74%) had internal septations. Surprisingly, contrast enhancement along the outer membrane adjacent to the cranium was noticed in all hematomas. There was also contrast enhancement along the inner membrane adjacent to the brain in more than one-third of the hematomas (37%). In approximately two-thirds of the cSDH (62%), there was a mass-like enhancement of the hematoma. Most hematomas (89%) were partially hypointense on T2*-GRE and/or susceptibility-weighted imaging (SWI). Restricted diffusion was detected in approximately one-third of the hematomas (33%).

Conclusion

Consistent contrast enhancement along the outer membrane, triangular-shaped contrast enhancement at the borders of the cSDH, and infrequent enhancement of the inner membrane may help to distinguish cSDH from other entities such as empyema and tumors. Mass-like enhancement may refer to non-solid hematomas and could be an indicator for hematoma growth and a possible surrogate for successful endovascular embolization. Restricted diffusion in a subdural mass is not specific for empyema but may also be found in cSDH.

A Radiological Assessment of Chronic Subdural Hematomas

Chronic subdural hematoma (CSDH), which generally occurs in elderly patients, is a frequently diagnosed condition in neurosurgical departments. Computed tomography (CT) and magnetic resonance imaging (MRI) are the most preferred diagnostic modalities for CSDH assessment. With early diagnosis and adequate management, CSDH may show favorable prognosis in majority of the patients; however, recurrence after surgery can occur in a significant number of patients. The recently increasing number of CSDH studies could reveal the prognostic factors affecting CSDH recurrence. Particularly, radiological characteristics regarding the internal architecture of CSDH are considered closely associated with recurrence in surgically treated CSDH patients. In this literature review, we evaluated the various diagnostic modalities of CSDH and its radiological characteristics on CT and MRI. Furthermore, we summarized the prognostic factors of recurrence for the hematoma type based on the radiological findings.

Comparisons of Radiological and Clinical Characteristics between Traumatic and Non-traumatic Subdural Hematoma Patients

Objective

Subdural hematoma (SDH) primarily occurs in elderly patients. While most patients have good prognosis, some do not. Hematoma recurrence is one of the factors influencing prognosis. Moreover, some characteristic radiological factors may increase the recurrence rate. The aim of this study was to investigate whether the presence of trauma influenced radiological characteristics and hematoma recurrence in SDH patients treated with burr hole trephination.

Methods

From January 2012 to December 2014, we selected 83 patients diagnosed with unilateral SDH using computed tomography and/or magnetic resonance imaging. We divided the patients into 2 groups based on the presence of trauma. We compared the 2 groups with multiple parameters, such as patient factors, radiological characteristics, and recurrence rate.

Results

Patients who had a prolonged international normalized ratio (INR) were significantly more common in the non-traumatic SDH group (22.2%:55.2%, p=0.002). There was no statistical difference in radiological parameters between the 2 groups. The recurrence rate was marginally higher in the non-traumatic SDH group (14.8%:17.2%, p=0.502), but this difference was not statistically significant.

Conclusion

There were no statistically significant differences in the radiological findings, including brain atrophy, hematoma density, thickness of hematoma, and degree of midline shifting between the 2 groups. The associated trauma history may not influence recurrence. Anticoagulants medication influence INR prolongation, and commonly shown in non-traumatic group, but not statistically. INR prolongation was statistically more common in non-traumatic SDH patients than in traumatic SDH patients. INR prolongation is only a different characteristic between 2 groups.

Preoperative MRI characteristics predict chronic subdural haematoma postoperative recurrence: a meta-analysis

PURPOSE

Prior studies have reported that preoperative T1 magnetic resonance imaging (MRI) signal iso- or hypointensity may indicate higher risk of postoperative chronic subdural haematoma recurrence (cSDH). The authors undertook a meta-analysis to determine whether preoperative MRI characteristics may predict recurrence and/or reoperation after initial surgical evacuation of cSDH.

MATERIALS AND METHODS

Embase, PubMed and Cochrane Library were queried to find articles published after 1990 that included data on preoperative brain MRIs obtained prior to burr hole or craniotomy haematoma evacuation of unilateral or bilateral cSDH and data on postoperative recurrence and/or repeat evacuation. The authors specifically investigated the T1 signal characteristics of the haematoma as they related to postoperative recurrence.

RESULTS

Five articles were identified that included preoperative MRI T1 signal characteristics and postoperative recurrence data. One study reported cSDH recurrence requiring reoperation as the primary outcome, whereas four studies reported SDH recurrence alone as the primary outcome. A total of 1081 patients with a total of 1290 cSDHs underwent surgical evacuation. In the combined analysis, there were 62 recurrences in 300 cases (20.7%) in the MRI T1 hypo- and/or iso-intensity groups and 59 recurrences in 885 cases (6.7%) in the MRI T1 other groups (combined odds ratio = 4.385 (95% CI 2.93-6.57)). There was low heterogeneity among studies (i² = 0%).

CONCLUSION

This meta-analysis suggests that preoperative MRI T1 hypo- or isointensity cSDH signal may predict increased postoperative SDH recurrence risk.

A comparative study of irrigation versus no irrigation during burr hole craniostomy to treat chronic subdural hematoma

BACKGROUND

Burr hole craniostomy is a widely used method for the evacuation of CSDH. However it is not clear whether the irrigation during operation improves the prognosis or gives rise to additional complications instead. This retrospective cohort study was conducted to determine this issue.

METHODS

Patients attending two medical centers in China who underwent burr hole drainage with irrigation (BHDI) or burr hole drainage without irrigation (BHD) for unilateral CSDH during January 2013 to December 2016 were included in this study. The patients' clinical information and follow-up data were retrospectively reviewed, and the radiologic findings were processed using the 3D Slicer software. The differences in outcomes were identified using t-test, chi-square test, or Fisher's exact test.

RESULTS

A total of 151 patients comprising 63 patients in the BHD group and 88 patients in the BHDI group were included. Patients in the BHDI group had a higher volume of pneumocrania on the first postoperative day than that of patients in the BHD group (p < 0.05). No significant differences were observed between the two approaches in rates of rebleeding, recurrence and other complications (p > 0.05).

CONCLUSIONS

Irrigation had no improvement in the long-term curative effect on CSDH, but it increased the risk of short-term complication in terms of pneumocrania. Therefore, this study suggests that irrigation is not an obligatory procedure during burr hole drainage.

Factors predicting contralateral hematoma growth after unilateral drainage of bilateral chronic subdural hematoma

OBJECTIVE

Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a recurrence rate of 9.2%–26.5% after bur hole surgery. Occasionally patients with bilateral CSDH undergo unilateral surgery because the contralateral hematoma is deemed to be asymptomatic, and in some of these patients the contralateral hematoma may subsequently enlarge, requiring additional surgery. The authors investigated the factors related to the growth of these hematomas.

METHODS

Ninety-three patients with bilateral CSDH who underwent unilateral bur hole surgery at Aizu Chuo Hospital were included in a retrospective analysis. Findings on preoperative MRI, preoperative thickness of the drained hematoma, and the influence of antiplatelet or anticoagulant drugs were considered and evaluated in univariate and multivariate analyses.

RESULTS

The overall growth rate was 19% (18 of 93 hematomas), and a significantly greater percentage of the hematomas that were iso- or hypointense on preoperative T1-weighted imaging showed growth compared with other hematomas (35.4% vs 2.3%, p < 0.001). Multivariate logistic regression analysis showed that findings on preoperative T1-weighted MRI were the sole significant predictor of hematoma growth, and other factors such as antiplatelet or anticoagulant drug use, patient age, patient sex, thickness of the treated hematoma, and T2-weighted MRI findings were not significantly related to hematoma growth. The adjusted odds ratio for hematoma growth in the T1 isointense/hypointense group relative to the T1 hyperintense group was 25.12 (95% CI 3.89–51.58, p < 0.01).

CONCLUSIONS

The findings of preoperative MRI, namely T1-weighted sequences, may be useful in predicting the growth of hematomas that did not undergo bur hole surgery in patients with bilateral CSDH.

Impact of Time Interval between Trauma Onset and Burr Hole Surgery on Recurrence of Late Subacute or Chronic Subdural Hematoma

Objective

Although subdural hematoma (SDH) is commonly treatable by burr hole surgery in the late subacute or chronic stage, there is no clear consensus regarding appropriate management and exact predictive factors for postoperative recurrence also remain unclear. The aim of this study was to evaluate risk factors associated with recurrence of SDH that requires burr hole surgery in the late subacute or chronic stage. We also identified the appropriate timing of surgery for reducing the recurrence.

Methods

We retrospectively reviewed 274 patients with SDH in the late subacute or chronic stage treated with burr hole surgery in our hospital between January 2007 and December 2014. Excluding patients with acute intracranial complications or unknown time of trauma onset left 216 patients included in the study.

Results

Of 216 patients with SDH in the late subacute or chronic stage, recurrence was observed in 36 patients (16.7%). The timing of the operation in patients with late subacute stage (15–28 days) resulted in a significant decrease in recurrence (RR, 0.33; 95% CI, 0.17–0.65; p=0.001) compared to chronic stage (>28 days). Otherwise, no significant risk factors were associated with recurrences including comorbidities and surgical details.

Conclusion

The results indicated that time from trauma onset to burr hole surgery may be important for decreasing the risk of recurrence. Therefore, unless patients can be treated conservatively without surgery, prompt surgical management is recommended in patients diagnosed as having late subacute or chronic subdural hematoma treatable by burr hole surgery, even when neurological deficits are unclear.

Role of neuroimaging in multidisciplinary approach towards Non-Alzheimer's dementia

Dementia is defined as chronic deterioration of intellectual function and cognitive skills significant enough to interfere with the ability to perform daily activities. Recent advances in the treatment of dementia have renewed interest in the use of various neuroimaging techniques that can assist in the diagnosis and differentiation of various subtypes. Neuroimaging and computational techniques have helped the radiological community to monitor disease progression of various neurodegenerative conditions presenting with dementia, such as Alzheimer disease, frontotemporal lobe dementia (FTLD), progressive supranuclear palsy (PSP) and multisystem atrophy-cerebellar variant (MSA-C), and their response to newer therapies. Prompt identification of treatable or reversible forms of dementia, such as tumours, subdural haemorrhage and intracranial dAVF, is crucial for the effective management of these conditions. It is also prudent to recognize the imaging spectrum of metabolic, infective and autoimmune diseases with rapidly progressing dementia, such as methanol toxicity, central pontine myelinolysis (CPM), delayed post hypoxic leukoencephalopathy (DPHL), HIV, Creutzfeldt-Jakob Disease (CJD), Sjogren's syndrome, multiple sclerosis (MS), radiation necrosis and Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS), which are difficult to treat and often require palliative care. This pictorial review emphasizes various non-Alzheimer’s dementia entities and discusses their imaging highlights.

Teaching Points

• Non Alzheimer’s dementia constitutes a broad spectrum of conditions.

• Neuroimaging plays an important role in differentiating treatable from irreversible dementia.

• Neuroimaging is often non-specific in early stages of neurodegenerative conditions with dementia.

• Neuroimaging plays an important role in the multimodal approach towards management of dementia.

Magnetic resonance imaging findings predict the recurrence of chronic subdural hematoma

The exact predictive factors for postoperative recurrence of chronic subdural hematoma (CSDH) are still unknown. Based on the preoperative magnetic resonance imaging (MRI), low recurrence rate of T1-hyperintensity hematoma was previously reported. We investigated the other types of radiological findings which are related to the recurrence rate of CSDH in large number of patients analyzed by multivariate logistic regression model. Preoperative MRI and postoperative computed tomography (CT) were performed and the influence of the preoperative use of antiplatelet or anticoagulant drugs was also studied. The overall recurrence rate was 9.3% (47 of 505 hematomas). The MRI T1-iso/hypointensity group showed a significantly higher recurrence rate (18.2%, 29 of 159) compared to the other groups (5.2%, 18 of 346; p < 0.001). Multivariate logistic regression analysis showed T1 classification was the solo significant prognostic predictor among various factors such as bilateral hematoma, antiplatelet or anticoagulant drug usage, residual hematoma on postoperative CT, and MRI classification (p < 0.001): adjusted odds ratio for the recurrence in T1-iso/hypointensity group relative to the T1-hyperintensity group was 5.58 [95% confidence interval (CI), 2.09-14.86] (p = 0.001). Postoperative residual hematoma and antiplatelet or anticoagulant drug usage did not increase the recurrence risk. The preoperative MRI findings, especially T1WI findings, have predictive value for postoperative recurrence of CSDH and the T1-iso/hypointensity group can be assumed to be a high recurrence risk group.

Multiple Episodes of Hemorrhage Identified in MRI of Chronic Subdural Hematomas

Objective

Septa within the hematoma cavity are common, especially in the mixed density chronic subdural hematomas (CSHs). Although CT remains the diagnosis of choice, MRI is superior to detect the membranes in CSHs. We could obtain MRIs in 64 patients with CSH. We examined the value of MRI to understand the history of CSH.

Methods

We retrospectively examined the medical records and MRIs of 64 consecutive patients. MRI was selected to find any organic causes of neurologic symptoms. We classified the CSHs into septated or non-septated group, since classification of the septa was frequently obscure.

Results

Septa were identified by MRI in 43 patients (67%). They were more common in the over 70-years-old group. Unknown causes were more common in the septated group, which implies they might suffer from multiple traumas. The signal intensity of the CSH was variable. The methods of treatment were different between two groups. Surgery was more common in the septated group (p=0.021). Surgery was performed in 57 patients (89%). Burr-hole drainage was successful in 55 patients, even in the septated group.

Conclusion

Septa within the hematoma cavity may be related to the multiple episodes of head trauma. Repeated trauma may cause acute bleedings over the CSHs, which is one of the pathogenic mechanisms of hematoma enlargement. MRI could show the history of CSH.

Multiple Densities of the Chronic Subdural Hematoma in CT Scans

Objective

Density of the chronic subdural hematoma (cSDH) is variable. It often appears to be mixed density. Multiple densities of cSDH may result from multiple episodes of trauma. We investigated the frequency of mixed density and the causes of head injuries representing each density.

Methods

We could collect 242 cases of chronic SDH. The cSDHs were classified into four groups; hypodensity, homogeneous isodensity, layered type, and mixed type on the basis of CT scans.

Results

The density of cSDH was isodense in 115 patients, hypodense in 31 patients, mixed in 79 cases, and layered in 17 cases. The cSDH was on the left side in 115 patients, on the right side in 70 patients, and bilateral in 40 patients. The history of trauma was identifiable in 122 patients. The etiology could be identified in 67.7% of the hypodense hematomas, while it was obscure in 59.5% of the mixed hematomas.

Conclusion

Mixed density of cSDH results from multiple episodes of trauma, usually in the aged. It is hard to remember all the trivial traumas for the patients with the mixed density cSDHs. Although there were membranes within the mixed density hematomas, burr-holes were usually enough to drain the hematomas.

Chronic expanding pituitary hematoma without rebleeding after pituitary apoplexy

Background:

Enlargement of intracerebral hematoma without rebleeding in chronic phase is a rare but well-known clinical condition, and is well-described as chronic expanding intracerebral hematoma. However, chronic enlargement of pituitary hematoma without rebleeding after pituitary apoplexy is extremely rare.

Case Description:

We report a case of chronic expanding pituitary hematoma without rebleeding after pituitary apoplexy. A 29-year-old male presented with sudden onset of headache and vomiting. Magnetic resonance imaging (MRI) demonstrated a pituitary mass lesion with hematoma, consistent with pituitary apoplexy. Neuro-ophthalmological examination revealed no visual field defect, and endocrinological evaluations showed an elevated prolactin level. Pituitary apoplexy due to a prolactinoma was the most likely diagnosis. He was conservatively treated because he exhibited no visual disturbance. Three weeks after the onset, he gradually began to complain of blurred vision and neuro-ophthalamological examination revealed bitemporal upper quadrant hemianopsia. MRI showed enlargement of the pituitary hematoma without any finding suggestive of rebleeding. This enlarged mass lesion compressed the chiasm. The patient was operated on via transsphenoidal approach. After dural opening, xanthochromic fluid spouted out, but no fresh clot could be detected within the cyst. After the operation, the visual field disturbance resolved completely. The possible mechanism of hematoma enlargement is considered to be expansion due to the serum exudation from capillaries of the hematoma capsule. This pathogenetic mechanism is common in enlargement of chronic subdural hematoma.

Conclusions:

This case is the first report of chronic expanding pituitary hematoma without rebleeding after pituitary apoplexy.

PlGF and sVEGFR-1 in chronic subdural hematoma: implications for hematoma development

Object

A considerable body of evidence indicates that inflammation and angiogenesis play a significant role in the development and progression of chronic subdural hematoma (CSDH). While various experimental and clinical studies have implicated placental growth factor (PlGF) in the processes that underpin pathological angiogenesis, no study has thus far investigated its expression in CSDH. The actions of PlGF and its related proangiogenic vascular endothelial growth factor (VEGF) are antagonized by a high-affinity soluble receptor, namely soluble VEGF receptor–1 (sVEGFR-1), and thus the ratio between sVEGFR-1 and angiogenic factors provides an index of angiogenic capacity.

Methods

In the present study, using an automated electrochemiluminescence assay, levels of PlGF and sVEGFR-1 were quantified in serum and hematoma fluid obtained in 16 patients with CSDH.

Results

Levels of PlGF and sVEGFR-1 were significantly higher in hematoma fluid than in serum (p < 0.0001). In serum, levels of sVEGFR-1 were higher than those of PlGF (p < 0.0001), whereas in hematoma fluid this difference was not apparent. Furthermore, the ratio of sVEGFR-1 to PlGF was significantly lower in hematoma fluid than in serum (p < 0.0001).

Conclusions

Given previous evidence indicating a role for PlGF in promoting angiogenesis, inflammatory cell chemotaxis, and stimulation, as well as its ability to amplify VEGF-driven signaling under conditions favoring pathological angiogenesis, enhanced expression of PlGF in hematoma fluid suggests the involvement of this factor in the mechanisms of inflammation and angiogenesis in CSDH. Furthermore, a reduced ratio of sVEGFR-1 to PlGF in hematoma fluid is consistent with the proangiogenic capacity of CSDH. Future studies are warranted to clarify the precise role of PlGF and sVEGFR-1 in CSDH.

Developing a model of chronic subdural hematoma

Chronic subdural hematoma (CSDH) is a common neurosurgical condition that has a high incidence in the increasing elderly population of many countries. Pathologically, it is defined as a persistent liquefied hematoma in the subdural space more than 3 weeks old that is generally encased by a membraneous capsule. CSDHs likely originate after minor head trauma, with a key factor in its development being the potential for a subdural cavity to permit its expansion within, which is usually due to craniocerebral disproportion. The pathogenesis of CSDH has been attributed to osmotic or oncotic pressure differences, although measurements of these factors in the CSDH fluid do not support this theory. Current belief is that CSDH arises from recurrent bleeding in the subdural space, caused by a cycle of local angiogenesis, inflammation, coagulation and ongoing fibrinolysis. However, because of a lack of detailed knowledge about the precise mechanisms, treatment is often limited to surgical interventions that are invasive and often prone to recurrence. Thus, it is possible that an easily reproducible and representative animal model of CSDH would facilitate research in the pathogenesis of CSDH and aid with development of treatment options.

Bilateral biconvex frontal chronic subdural hematoma mimicking extradural hematoma

Chronic subdural hematoma (CSDH) is one of the most common clinical entities encountered in daily neurosurgical practice. The advent of computed tomography (CT) has made a major impact on the radiological diagnosis of CSDH. Although unilateral chronic isodense subdural hematomas as a result of indirect signs of a space-occupying lesion are easily recognizable on CT, bilateral CSDH may cause considerable difficulty, particularly when it is biconvex in shape as discussed in the present case. A judicious use of magnetic resonance imaging will help in making the diagnosis and for the management of such lesions.

A giant bilateral calcified chronic subdural hematoma

BACKGROUND

A calcified chronic subdural hematoma is a rare disease and its neuroradiological presentation is variable. The degree of calcification extends from thin calcified inner membranes to dense calcification and even ossification of the hematoma. Previous reports described a maximum of two hematoma cavities with calcified inner hematoma membranes.

METHODS

Neuroimaging report with illustrative computerized tomography images.

RESULTS

A patient with a bilateral symptomatic calcified chronic subdural hematoma, or so-called "armoured brain", was admitted to our intensive care unit with clinical signs of increased intracranial pressure. Computerized cranial tomography demonstrated multiple bilaterally located hematoma cavities with thin calcified inner membranes. After neurosurgical intervention by bilateral burr hole trepanation, clinical symptoms improved.

CONCLUSIONS

Our case of a calcified chronic subdural hematoma presents with an uncommon imaging pattern with more than four hematoma cavities bounded by predominantly convex- and concave-configured thin calcified inner membranes.

Relationship between supratentorial arachnoid cyst and chronic subdural hematoma: neuroradiological evidence and surgical treatment

Object

Arachnoid cysts are relatively common congenital intracranial mass lesions that arise during the development of the meninges. They can be complicated by the formation of an ipsilateral chronic subdural hematoma (CSDH) after minor cranial trauma. Treatment of these coexisting conditions remains controversial. In this study the authors describe the anatomical, clinical, and neuroradiological features and outcome in a series of patients whose CSDH associated with arachnoid cysts were managed surgically by draining the hematoma alone and leaving the cyst intact. The authors based this surgical management on histological and neuroradiological observations concerning these associated medical conditions.

Methods

A series of 8 patients with CSDHs associated with arachnoid cysts underwent surgery to drain the hematoma though a bur hole. The arachnoid cyst was left intact. Postoperative follow-up included CT scanning and T1- and T2-weighted MR imaging.

Results

Clinical, anatomical, and radiological observations suggest that because separate membranes cover arachnoid cysts and the related hematoma, arachnoid cysts remain unaffected by the subdural bleeding. In the present study, these observations received support from the neuroimaging appearances, suggesting that arachnoid cysts related to hematoma contained only blood breakdown products from the hematoma that had filtered through the reciprocal dividing membranes.

Conclusions

Arachnoid cysts associated with SDH are anatomically separate conditions whose neurological symptoms respond to surgical drainage of the CSDH alone.