Large subdural effusions after angiography mimicking acute subdural hematoma

Pitfalls in the diagnosis of subdural hemorrhage - Mimics and uncommon causes

PURPOSE

Subdural hemorrhage (SDH), the accumulation of blood between the dura and arachnoid mater, is one of the most commonly encountered traumatic findings in emergency radiology setting. The purpose of this essay is to review the pitfalls in the diagnosis of SDH including a) mimics on CT imaging and b) etiology other than accidental trauma. We describe several entities that closely mimic SDH on non-contrast CT scans. A knowledge of these mimics is essential in the emergency setting since overdiagnosis of SDH can lead to unnecessary hospital admissions, potentially invasive procedures, or even delay in necessary treatment. The mimics of SDH on non-contrast head CT include: PATHOLOGIC ENTITIES IATROGENIC MIMICS ANATOMIC/PHYSIOLOGIC MIMICS ARTIFACTUAL MIMICSWe also briefly review non-accidental and non-traumatic causes of SDH. Although, the most common cause of SDH is accidental trauma, other routinely encountered causes of SDH include coagulopathy, non-accidental trauma, cranial surgery, vascular malformations etc. CONCLUSION: Clinicians dealing with SDH in the emergency setting should consider SDH mimics and less common etiologies of SDH in order to facilitate appropriate patient management.

Subdural contrast extravasation after percutaneous coronary intervention mimicking acute subdural hematoma: A case report

RATIONALE

Subdural contrast extravasation (SCE) is a rare and possible complication following the intravascular injection of a contrast agent. We report a case of interhemispheric SCE detected by computed tomography (CT) after percutaneous coronary intervention.

PATIENT CONCERNS

A 71-year-old man suddenly lost consciousness and fainted 2 hours prior with a head trauma history. Percutaneous coronary intervention was performed on the second day.

DIAGNOSES

Head CT findings showed that the anterior longitudinal fissure of the brain was banded with high density and was uneven in thickness. The edge of the falx side of the brain was straight, smooth, and sharp, and the edge of the brain parenchyma was clear, without obvious edema or a space-occupying effect.

INTERVENTIONS

Ticagrelor was given as an antiplatelet therapy; analgesic, antispasmodic symptomatic and supportive treatment was also administered.

OUTCOMES

Two days later, the band-like high density between cerebral hemispheres was completely absorbed, and the patient's condition improved and his headache resolved.

LESSONS

SCE is relatively uncommon during or after the intravascular injection of contrast media. Familiarity with the clinical features and CT findings of SCE may increase clinicians' awareness of this disease, thus avoiding potential misdiagnosis and mistreatment.

Typical subdural contrast effusion secondary to endovascular treatment of a pediatric pial arteriovenous fistula

Subdural contrast effusion secondary to endovascular treatment is exceptionally rare and might be mistaken as subdural hematoma because of similar hyperattenuation on computer tomography. The authors present the case of a 13-month-old girl with a history of increased head circumference and developmental retardation. Cerebral digital subtraction angiography showed a high-flow pial arteriovenous fistula fed by multiple arteries on the right cerebellar surface, with occlusion of the right sigmoid sinus and severe stenosis of the left sigmoid sinus. Staged endovascular treatments were performed to eliminate the fistula. Follow-up head computer tomography scans performed 3 h after both procedures demonstrated typical high-density subdural effusion with computer tomography attenuation value similar to hemorrhage. These effusions did not aggravate the condition and disappeared spontaneously 32 h after the first treatment and 29 h after the second, respectively.

Subdural contrast effusion during endovascular therapy: case report

Accumulation of contrast medium in the subdural space after diagnostic intraarterial contrast administration is a rare observation. The authors report the case of a subdural contrast effusion (SCE) presenting during endovascular treatment of an intracranial dural arteriovenous fistula (DAVF) mimicking an acute subdural hematoma. Differentiation between the two by computed tomography (CT) or intraprocedural Dyna CT and early neurological examination can be crucial for patient management. We believe that repeated large-volume contrast injections via large-bore intermediate catheters into the territory of an (even partly) occluded DAVF may induce leakage of contrast medium into the extravascular subdural space thereby causing a SCE.

A case of post angiography subdural collection contrast enhancement: Time course of attenuation reduction

The leakage of contrast material into the subdural space following intra-arterial or intravenous administration can present as hyperattenuating subdural collections on noncontrast head computed tomography (CT) scan, mimicking subdural hematomas. Such a finding can potentially initiate erroneous intervention or hinder thromboprophylaxis treatment. We report the time course of attenuation changes in enhancing subdural collections of a patient with suspected stroke following percutaneous coronary intervention. The patient had simple fluid attenuation subdural collections (hygromas) on preprocedure head CT scan, which showed gradually increasing attenuation on 2- and 10-hours post angiography CT scans. On delayed follow-up head CT scan, at 24 and 31 hours after the percutaneous coronary intervention, the subdural collection attenuation returned to preprocedural levels. In this patient, findings on an MRI obtained 9 hours after the procedure, were not in favor of a subdural hematoma. This case highlights the likelihood of contrast leakage into subdural space, mimicking extra-axial hemorrhage on head CT scans, and the time needed for normalization of subdural collection attenuation.

Dual-Energy CT in Enhancing Subdural Effusions that Masquerade as Subdural Hematomas: Diagnosis with Virtual High-Monochromatic (190-keV) Images

BACKGROUND AND PURPOSE

Extravasation of iodinated contrast into subdural space following contrast-enhanced radiographic studies results in hyperdense subdural effusions, which can be mistaken as acute subdural hematomas on follow-up noncontrast head CTs. Our aim was to identify the factors associated with contrast-enhancing subdural effusion, characterize diffusion and washout kinetics of iodine in enhancing subdural effusion, and assess the utility of dual-energy CT in differentiating enhancing subdural effusion from subdural hematoma.

MATERIALS AND METHODS

We retrospectively analyzed follow-up head dual-energy CT studies in 423 patients with polytrauma who had undergone contrast-enhanced whole-body CT. Twenty-four patients with enhancing subdural effusion composed the study group, and 24 randomly selected patients with subdural hematoma were enrolled in the comparison group. Postprocessing with syngo.via was performed to determine the diffusion and washout kinetics of iodine. The sensitivity and specificity of dual-energy CT for the diagnosis of enhancing subdural effusion were determined with 120-kV, virtual monochromatic energy (190-keV) and virtual noncontrast images.

RESULTS

Patients with enhancing subdural effusion were significantly older (mean, 69 years; 95% CI, 60-78 years; P < .001) and had a higher incidence of intracranial hemorrhage (P = .001). Peak iodine concentration in enhancing subdural effusions was reached within the first 8 hours of contrast administration with a mean of 0.98 mg/mL (95% CI, 0.81-1.13 mg/mL), and complete washout was achieved at 38 hours. For the presence of a hyperdense subdural collection on 120-kV images with a loss of hyperattenuation on 190-keV and virtual noncontrast images, when considered as a true-positive for enhancing subdural effusion, the sensitivity was 100% (95% CI, 85.75%-100%) and the specificity was 91.67% (95% CI, 73%-99%).

CONCLUSIONS

Dual-energy CT has a high sensitivity and specificity in differentiating enhancing subdural effusion from subdural hematoma. Hence, dual-energy CT has a potential to obviate follow-up studies.

Subdural Hematoma Mimickers: A Systematic Review

BACKGROUND

A variety of subdural pathologies that may mimic hematomas are reported in the literature. We aimed to identify the atypical clinical and radiologic presentations of subdural masses that may mimic subdural hematomas.

METHODS

A systematic review of MEDLINE and Embase was conducted independently by 2 reviewers to identify articles describing subdural hematoma mimickers. We also present a patient from our institution with a subdural pathology mimicking a subdural hematoma. We analyzed patient clinical presentations, underlying pathologies, radiologic findings, and clinical outcomes.

RESULTS

We included 43 articles totaling 48 patients. The mean ± SD patient age was 55.7 ± 16.8 years. Of the 45 cases describing patient history, 13 patients (27%) had a history of trauma. The underlying pathologies of the 48 subdural collections were 10 metastasis (21%), 14 lymphoma (29%), 7 sarcoma (15%), 4 infectious (8%), 4 autoimmune (8%), and 9 miscellaneous (19%). Findings on computed tomography (CT) scan were 18 hyperdense (41%), 11 hypodense (25%), 9 isodense (20%), 3 isodense/hyperdense (7%), and 3 hypodense/isodense (7%). Thirty-four patients (71%) were treated surgically; among these patients, 65% had symptom resolution. Neither the pathology (P = 0.337) nor the management strategy (P = 0.671) was correlated with improved functional outcomes.

CONCLUSIONS

Identification of atypical history and radiologic features should prompt further diagnostic tests, including magnetic resonance imaging (MRI), to elucidate the proper diagnosis, given that certain pathologies may be managed nonsurgically. A subdural collection that is hyperdense on CT scan and hyperintense on T2-weighted MRI, along with a history of progressive headache with no trauma, may raise the suspicion of an atypical subdural pathology.

Enhancing subdural effusions mimicking acute subdural hematomas following angiography and endovascular procedures: report of 2 cases

Hyperdense enhancing subdural effusion due to contrast extravasation has been recently described as a potential mimicker of acute subdural hematoma following a percutaneous coronary procedure. Herein, the authors report on 2 patients who presented with subarachnoid hemorrhage from ruptured cerebral aneurysms and who developed enhancing subdural effusions mimicking acute subdural hematomas after angiography and endovascular coil placement. In 1 case, the subdural effusions completely cleared but recurred after a second angiography. CT attenuation values higher than expected for blood, as well as the evolution of the effusions and density over time, allowed for differentiation of enhancing subdural effusions from acute subdural hematomas.